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a31d50ab29
stb/stb_image.c
Sean Barrett a31d50ab29 more warnings, use stdint.h if possible
2014-05-27 12:36:01 -07:00

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/* stbi-1.35 - public domain JPEG/PNG reader - http://nothings.org/stb_image.c
when you control the images you're loading
no warranty implied; use at your own risk
QUICK NOTES:
Primarily of interest to game developers and other people who can
avoid problematic images and only need the trivial interface
JPEG baseline (no JPEG progressive)
PNG 8-bit-per-channel only
TGA (not sure what subset, if a subset)
BMP non-1bpp, non-RLE
PSD (composited view only, no extra channels)
GIF (*comp always reports as 4-channel)
HDR (radiance rgbE format)
PIC (Softimage PIC)
- decode from memory or through FILE (define STBI_NO_STDIO to remove code)
- decode from arbitrary I/O callbacks
- overridable dequantizing-IDCT, YCbCr-to-RGB conversion (define STBI_SIMD)
Latest revisions:
1.35 (2014-05-27) warnings, bugfixes, etc
1.34 (unknown ) warning fix
1.33 (2011-07-14) minor fixes suggested by Dave Moore
1.32 (2011-07-13) info support for all filetypes (SpartanJ)
1.31 (2011-06-19) a few more leak fixes, bug in PNG handling (SpartanJ)
1.30 (2011-06-11) added ability to load files via io callbacks (Ben Wenger)
1.29 (2010-08-16) various warning fixes from Aurelien Pocheville
1.28 (2010-08-01) fix bug in GIF palette transparency (SpartanJ)
See end of file for full revision history.
TODO:
stbi_info support for BMP,PSD,HDR,PIC
============================ Contributors =========================
Image formats Bug fixes & warning fixes
Sean Barrett (jpeg, png, bmp) Marc LeBlanc
Nicolas Schulz (hdr, psd) Christpher Lloyd
Jonathan Dummer (tga) Dave Moore
Jean-Marc Lienher (gif) Won Chun
Tom Seddon (pic) the Horde3D community
Thatcher Ulrich (psd) Janez Zemva
Jonathan Blow
Laurent Gomila
Extensions, features Aruelien Pocheville
Jetro Lauha (stbi_info) Ryamond Barbiero
James "moose2000" Brown (iPhone PNG) David Woo
Ben "Disch" Wenger (io callbacks) Roy Eltham
Martin "SpartanJ" Golini Luke Graham
Thomas Ruf
John Bartholomew
Optimizations & bugfixes Ken Hamada
Fabian "ryg" Giesen Cort Stratton
Blazej Dariusz Roszkowski
Thibault Reuille
If your name should be here but Paul Du Bois
isn't let Sean know. Guillaume George
*/
#ifndef STBI_INCLUDE_STB_IMAGE_H
#define STBI_INCLUDE_STB_IMAGE_H
// To get a header file for this, either cut and paste the header,
// or create stb_image.h, #define STBI_HEADER_FILE_ONLY, and
// then include stb_image.c from it.
//// begin header file ////////////////////////////////////////////////////
//
// Limitations:
// - no jpeg progressive support
// - non-HDR formats support 8-bit samples only (jpeg, png)
// - no delayed line count (jpeg) -- IJG doesn't support either
// - no 1-bit BMP
// - GIF always returns *comp=4
//
// Basic usage (see HDR discussion below):
// int x,y,n;
// unsigned char *data = stbi_load(filename, &x, &y, &n, 0);
// // ... process data if not NULL ...
// // ... x = width, y = height, n = # 8-bit components per pixel ...
// // ... replace '0' with '1'..'4' to force that many components per pixel
// // ... but 'n' will always be the number that it would have been if you said 0
// stbi_image_free(data)
//
// Standard parameters:
// int *x -- outputs image width in pixels
// int *y -- outputs image height in pixels
// int *comp -- outputs # of image components in image file
// int req_comp -- if non-zero, # of image components requested in result
//
// The return value from an image loader is an 'unsigned char *' which points
// to the pixel data. The pixel data consists of *y scanlines of *x pixels,
// with each pixel consisting of N interleaved 8-bit components; the first
// pixel pointed to is top-left-most in the image. There is no padding between
// image scanlines or between pixels, regardless of format. The number of
// components N is 'req_comp' if req_comp is non-zero, or *comp otherwise.
// If req_comp is non-zero, *comp has the number of components that _would_
// have been output otherwise. E.g. if you set req_comp to 4, you will always
// get RGBA output, but you can check *comp to easily see if it's opaque.
//
// An output image with N components has the following components interleaved
// in this order in each pixel:
//
// N=#comp components
// 1 grey
// 2 grey, alpha
// 3 red, green, blue
// 4 red, green, blue, alpha
//
// If image loading fails for any reason, the return value will be NULL,
// and *x, *y, *comp will be unchanged. The function stbi_failure_reason()
// can be queried for an extremely brief, end-user unfriendly explanation
// of why the load failed. Define STBI_NO_FAILURE_STRINGS to avoid
// compiling these strings at all, and STBI_FAILURE_USERMSG to get slightly
// more user-friendly ones.
//
// Paletted PNG, BMP, GIF, and PIC images are automatically depalettized.
//
// ===========================================================================
//
// iPhone PNG support:
//
// By default we convert iphone-formatted PNGs back to RGB; nominally they
// would silently load as BGR, except the existing code should have just
// failed on such iPhone PNGs. But you can disable this conversion by
// by calling stbi_convert_iphone_png_to_rgb(0), in which case
// you will always just get the native iphone "format" through.
//
// Call stbi_set_unpremultiply_on_load(1) as well to force a divide per
// pixel to remove any premultiplied alpha *only* if the image file explicitly
// says there's premultiplied data (currently only happens in iPhone images,
// and only if iPhone convert-to-rgb processing is on).
//
// ===========================================================================
//
// HDR image support (disable by defining STBI_NO_HDR)
//
// stb_image now supports loading HDR images in general, and currently
// the Radiance .HDR file format, although the support is provided
// generically. You can still load any file through the existing interface;
// if you attempt to load an HDR file, it will be automatically remapped to
// LDR, assuming gamma 2.2 and an arbitrary scale factor defaulting to 1;
// both of these constants can be reconfigured through this interface:
//
// stbi_hdr_to_ldr_gamma(2.2f);
// stbi_hdr_to_ldr_scale(1.0f);
//
// (note, do not use _inverse_ constants; stbi_image will invert them
// appropriately).
//
// Additionally, there is a new, parallel interface for loading files as
// (linear) floats to preserve the full dynamic range:
//
// float *data = stbi_loadf(filename, &x, &y, &n, 0);
//
// If you load LDR images through this interface, those images will
// be promoted to floating point values, run through the inverse of
// constants corresponding to the above:
//
// stbi_ldr_to_hdr_scale(1.0f);
// stbi_ldr_to_hdr_gamma(2.2f);
//
// Finally, given a filename (or an open file or memory block--see header
// file for details) containing image data, you can query for the "most
// appropriate" interface to use (that is, whether the image is HDR or
// not), using:
//
// stbi_is_hdr(char *filename);
//
// ===========================================================================
//
// I/O callbacks
//
// I/O callbacks allow you to read from arbitrary sources, like packaged
// files or some other source. Data read from callbacks are processed
// through a small internal buffer (currently 128 bytes) to try to reduce
// overhead.
//
// The three functions you must define are "read" (reads some bytes of data),
// "skip" (skips some bytes of data), "eof" (reports if the stream is at the end).
#ifndef STBI_NO_STDIO
#if defined(_MSC_VER) && _MSC_VER >= 1400
#define _CRT_SECURE_NO_WARNINGS // suppress warnings about fopen()
#pragma warning(push)
#pragma warning(disable:4996) // suppress even more warnings about fopen()
#endif
#include <stdio.h>
#endif // STBI_NO_STDIO
#define STBI_VERSION 1
enum
{
STBI_default = 0, // only used for req_comp
STBI_grey = 1,
STBI_grey_alpha = 2,
STBI_rgb = 3,
STBI_rgb_alpha = 4
};
typedef unsigned char stbi_uc;
#ifdef __cplusplus
extern "C" {
#endif
//////////////////////////////////////////////////////////////////////////////
//
// PRIMARY API - works on images of any type
//
//
// load image by filename, open file, or memory buffer
//
extern stbi_uc *stbi_load_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *comp, int req_comp);
#ifndef STBI_NO_STDIO
extern stbi_uc *stbi_load (char const *filename, int *x, int *y, int *comp, int req_comp);
extern stbi_uc *stbi_load_from_file (FILE *f, int *x, int *y, int *comp, int req_comp);
// for stbi_load_from_file, file pointer is left pointing immediately after image
#endif
typedef struct
{
int (*read) (void *user,char *data,int size); // fill 'data' with 'size' bytes. return number of bytes actually read
void (*skip) (void *user,int n); // skip the next 'n' bytes, or 'unget' the last -n bytes if negative
int (*eof) (void *user); // returns nonzero if we are at end of file/data
} stbi_io_callbacks;
extern stbi_uc *stbi_load_from_callbacks (stbi_io_callbacks const *clbk, void *user, int *x, int *y, int *comp, int req_comp);
#ifndef STBI_NO_HDR
extern float *stbi_loadf_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *comp, int req_comp);
#ifndef STBI_NO_STDIO
extern float *stbi_loadf (char const *filename, int *x, int *y, int *comp, int req_comp);
extern float *stbi_loadf_from_file (FILE *f, int *x, int *y, int *comp, int req_comp);
#endif
extern float *stbi_loadf_from_callbacks (stbi_io_callbacks const *clbk, void *user, int *x, int *y, int *comp, int req_comp);
extern void stbi_hdr_to_ldr_gamma(float gamma);
extern void stbi_hdr_to_ldr_scale(float scale);
extern void stbi_ldr_to_hdr_gamma(float gamma);
extern void stbi_ldr_to_hdr_scale(float scale);
#endif // STBI_NO_HDR
// stbi_is_hdr is always defined
extern int stbi_is_hdr_from_callbacks(stbi_io_callbacks const *clbk, void *user);
extern int stbi_is_hdr_from_memory(stbi_uc const *buffer, int len);
#ifndef STBI_NO_STDIO
extern int stbi_is_hdr (char const *filename);
extern int stbi_is_hdr_from_file(FILE *f);
#endif // STBI_NO_STDIO
// get a VERY brief reason for failure
// NOT THREADSAFE
extern const char *stbi_failure_reason (void);
// free the loaded image -- this is just free()
extern void stbi_image_free (void *retval_from_stbi_load);
// get image dimensions & components without fully decoding
extern int stbi_info_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *comp);
extern int stbi_info_from_callbacks(stbi_io_callbacks const *clbk, void *user, int *x, int *y, int *comp);
#ifndef STBI_NO_STDIO
extern int stbi_info (char const *filename, int *x, int *y, int *comp);
extern int stbi_info_from_file (FILE *f, int *x, int *y, int *comp);
#endif
// for image formats that explicitly notate that they have premultiplied alpha,
// we just return the colors as stored in the file. set this flag to force
// unpremultiplication. results are undefined if the unpremultiply overflow.
extern void stbi_set_unpremultiply_on_load(int flag_true_if_should_unpremultiply);
// indicate whether we should process iphone images back to canonical format,
// or just pass them through "as-is"
extern void stbi_convert_iphone_png_to_rgb(int flag_true_if_should_convert);
// ZLIB client - used by PNG, available for other purposes
extern char *stbi_zlib_decode_malloc_guesssize(const char *buffer, int len, int initial_size, int *outlen);
extern char *stbi_zlib_decode_malloc_guesssize_headerflag(const char *buffer, int len, int initial_size, int *outlen, int parse_header);
extern char *stbi_zlib_decode_malloc(const char *buffer, int len, int *outlen);
extern int stbi_zlib_decode_buffer(char *obuffer, int olen, const char *ibuffer, int ilen);
extern char *stbi_zlib_decode_noheader_malloc(const char *buffer, int len, int *outlen);
extern int stbi_zlib_decode_noheader_buffer(char *obuffer, int olen, const char *ibuffer, int ilen);
// define faster low-level operations (typically SIMD support)
#ifdef STBI_SIMD
typedef void (*stbi_idct_8x8)(stbi_uc *out, int out_stride, short data[64], unsigned short *dequantize);
// compute an integer IDCT on "input"
// input[x] = data[x] * dequantize[x]
// write results to 'out': 64 samples, each run of 8 spaced by 'out_stride'
// CLAMP results to 0..255
typedef void (*stbi_YCbCr_to_RGB_run)(stbi_uc *output, stbi_uc const *y, stbi_uc const *cb, stbi_uc const *cr, int count, int step);
// compute a conversion from YCbCr to RGB
// 'count' pixels
// write pixels to 'output'; each pixel is 'step' bytes (either 3 or 4; if 4, write '255' as 4th), order R,G,B
// y: Y input channel
// cb: Cb input channel; scale/biased to be 0..255
// cr: Cr input channel; scale/biased to be 0..255
extern void stbi_install_idct(stbi_idct_8x8 func);
extern void stbi_install_YCbCr_to_RGB(stbi_YCbCr_to_RGB_run func);
#endif // STBI_SIMD
#ifdef __cplusplus
}
#endif
//
//
//// end header file /////////////////////////////////////////////////////
#endif // STBI_INCLUDE_STB_IMAGE_H
#ifndef STBI_HEADER_FILE_ONLY
#ifndef STBI_NO_HDR
#include <math.h> // ldexp
#include <string.h> // strcmp, strtok
#endif
#ifndef STBI_NO_STDIO
#include <stdio.h>
#endif
#include <stdlib.h>
#include <memory.h>
#include <assert.h>
#include <stdarg.h>
#include <stddef.h> // ptrdiff_t on osx
#ifndef _MSC_VER
#ifdef __cplusplus
#define stbi_inline inline
#else
#define stbi_inline
#endif
#else
#define stbi_inline __forceinline
#endif
#ifdef _MSC_VER
typedef unsigned char stbi__uint8;
typedef unsigned short stbi__uint16;
typedef signed short stbi__int16;
typedef unsigned int stbi__uint32;
typedef signed int stbi__int32;
#else
#include <stdint.h>
typedef uint8_t stbi__uint8;
typedef uint16_t stbi__uint16;
typedef int16_t stbi__int16;
typedef uint32_t stbi__uint32;
typedef int32_t stbi__int32;
#endif
// should produce compiler error if size is wrong
typedef unsigned char validate_uint32[sizeof(stbi__uint32)==4 ? 1 : -1];
#ifdef _MSC_VER
#define STBI_NOTUSED(v) (void)(v)
#else
#define STBI_NOTUSED(v) (void)sizeof(v)
#endif
#ifdef _MSC_VER
#define STBI_HAS_LROTL
#endif
#ifdef STBI_HAS_LROTL
#define stbi_lrot(x,y) _lrotl(x,y)
#else
#define stbi_lrot(x,y) (((x) << (y)) | ((x) >> (32 - (y))))
#endif
///////////////////////////////////////////////
//
// stbi struct and start_xxx functions
// stbi structure is our basic context used by all images, so it
// contains all the IO context, plus some basic image information
typedef struct
{
stbi__uint32 img_x, img_y;
int img_n, img_out_n;
stbi_io_callbacks io;
void *io_user_data;
int read_from_callbacks;
int buflen;
stbi__uint8 buffer_start[128];
stbi__uint8 *img_buffer, *img_buffer_end;
stbi__uint8 *img_buffer_original;
} stbi;
static void refill_buffer(stbi *s);
// initialize a memory-decode context
static void start_mem(stbi *s, stbi__uint8 const *buffer, int len)
{
s->io.read = NULL;
s->read_from_callbacks = 0;
s->img_buffer = s->img_buffer_original = (stbi__uint8 *) buffer;
s->img_buffer_end = (stbi__uint8 *) buffer+len;
}
// initialize a callback-based context
static void start_callbacks(stbi *s, stbi_io_callbacks *c, void *user)
{
s->io = *c;
s->io_user_data = user;
s->buflen = sizeof(s->buffer_start);
s->read_from_callbacks = 1;
s->img_buffer_original = s->buffer_start;
refill_buffer(s);
}
#ifndef STBI_NO_STDIO
static int stdio_read(void *user, char *data, int size)
{
return (int) fread(data,1,size,(FILE*) user);
}
static void stdio_skip(void *user, int n)
{
fseek((FILE*) user, n, SEEK_CUR);
}
static int stdio_eof(void *user)
{
return feof((FILE*) user);
}
static stbi_io_callbacks stbi_stdio_callbacks =
{
stdio_read,
stdio_skip,
stdio_eof,
};
static void start_file(stbi *s, FILE *f)
{
start_callbacks(s, &stbi_stdio_callbacks, (void *) f);
}
//static void stop_file(stbi *s) { }
#endif // !STBI_NO_STDIO
static void stbi_rewind(stbi *s)
{
// conceptually rewind SHOULD rewind to the beginning of the stream,
// but we just rewind to the beginning of the initial buffer, because
// we only use it after doing 'test', which only ever looks at at most 92 bytes
s->img_buffer = s->img_buffer_original;
}
static int stbi_jpeg_test(stbi *s);
static stbi_uc *stbi_jpeg_load(stbi *s, int *x, int *y, int *comp, int req_comp);
static int stbi_jpeg_info(stbi *s, int *x, int *y, int *comp);
static int stbi_png_test(stbi *s);
static stbi_uc *stbi_png_load(stbi *s, int *x, int *y, int *comp, int req_comp);
static int stbi_png_info(stbi *s, int *x, int *y, int *comp);
static int stbi_bmp_test(stbi *s);
static stbi_uc *stbi_bmp_load(stbi *s, int *x, int *y, int *comp, int req_comp);
static int stbi_tga_test(stbi *s);
static stbi_uc *stbi_tga_load(stbi *s, int *x, int *y, int *comp, int req_comp);
static int stbi_tga_info(stbi *s, int *x, int *y, int *comp);
static int stbi_psd_test(stbi *s);
static stbi_uc *stbi_psd_load(stbi *s, int *x, int *y, int *comp, int req_comp);
#ifndef STBI_NO_HDR
static int stbi_hdr_test(stbi *s);
static float *stbi_hdr_load(stbi *s, int *x, int *y, int *comp, int req_comp);
#endif
static int stbi_pic_test(stbi *s);
static stbi_uc *stbi_pic_load(stbi *s, int *x, int *y, int *comp, int req_comp);
static int stbi_gif_test(stbi *s);
static stbi_uc *stbi_gif_load(stbi *s, int *x, int *y, int *comp, int req_comp);
static int stbi_gif_info(stbi *s, int *x, int *y, int *comp);
// this is not threadsafe
static const char *failure_reason;
const char *stbi_failure_reason(void)
{
return failure_reason;
}
static int e(const char *str)
{
failure_reason = str;
return 0;
}
// e - error
// epf - error returning pointer to float
// epuc - error returning pointer to unsigned char
#ifdef STBI_NO_FAILURE_STRINGS
#define e(x,y) 0
#elif defined(STBI_FAILURE_USERMSG)
#define e(x,y) e(y)
#else
#define e(x,y) e(x)
#endif
#define epf(x,y) ((float *) (e(x,y)?NULL:NULL))
#define epuc(x,y) ((unsigned char *) (e(x,y)?NULL:NULL))
void stbi_image_free(void *retval_from_stbi_load)
{
free(retval_from_stbi_load);
}
#ifndef STBI_NO_HDR
static float *ldr_to_hdr(stbi_uc *data, int x, int y, int comp);
static stbi_uc *hdr_to_ldr(float *data, int x, int y, int comp);
#endif
static unsigned char *stbi_load_main(stbi *s, int *x, int *y, int *comp, int req_comp)
{
if (stbi_jpeg_test(s)) return stbi_jpeg_load(s,x,y,comp,req_comp);
if (stbi_png_test(s)) return stbi_png_load(s,x,y,comp,req_comp);
if (stbi_bmp_test(s)) return stbi_bmp_load(s,x,y,comp,req_comp);
if (stbi_gif_test(s)) return stbi_gif_load(s,x,y,comp,req_comp);
if (stbi_psd_test(s)) return stbi_psd_load(s,x,y,comp,req_comp);
if (stbi_pic_test(s)) return stbi_pic_load(s,x,y,comp,req_comp);
#ifndef STBI_NO_HDR
if (stbi_hdr_test(s)) {
float *hdr = stbi_hdr_load(s, x,y,comp,req_comp);
return hdr_to_ldr(hdr, *x, *y, req_comp ? req_comp : *comp);
}
#endif
// test tga last because it's a crappy test!
if (stbi_tga_test(s))
return stbi_tga_load(s,x,y,comp,req_comp);
return epuc("unknown image type", "Image not of any known type, or corrupt");
}
#ifndef STBI_NO_STDIO
unsigned char *stbi_load(char const *filename, int *x, int *y, int *comp, int req_comp)
{
FILE *f = fopen(filename, "rb");
unsigned char *result;
if (!f) return epuc("can't fopen", "Unable to open file");
result = stbi_load_from_file(f,x,y,comp,req_comp);
fclose(f);
return result;
}
unsigned char *stbi_load_from_file(FILE *f, int *x, int *y, int *comp, int req_comp)
{
unsigned char *result;
stbi s;
start_file(&s,f);
result = stbi_load_main(&s,x,y,comp,req_comp);
if (result) {
// need to 'unget' all the characters in the IO buffer
fseek(f, - (int) (s.img_buffer_end - s.img_buffer), SEEK_CUR);
}
return result;
}
#endif //!STBI_NO_STDIO
unsigned char *stbi_load_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *comp, int req_comp)
{
stbi s;
start_mem(&s,buffer,len);
return stbi_load_main(&s,x,y,comp,req_comp);
}
unsigned char *stbi_load_from_callbacks(stbi_io_callbacks const *clbk, void *user, int *x, int *y, int *comp, int req_comp)
{
stbi s;
start_callbacks(&s, (stbi_io_callbacks *) clbk, user);
return stbi_load_main(&s,x,y,comp,req_comp);
}
#ifndef STBI_NO_HDR
float *stbi_loadf_main(stbi *s, int *x, int *y, int *comp, int req_comp)
{
unsigned char *data;
#ifndef STBI_NO_HDR
if (stbi_hdr_test(s))
return stbi_hdr_load(s,x,y,comp,req_comp);
#endif
data = stbi_load_main(s, x, y, comp, req_comp);
if (data)
return ldr_to_hdr(data, *x, *y, req_comp ? req_comp : *comp);
return epf("unknown image type", "Image not of any known type, or corrupt");
}
float *stbi_loadf_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *comp, int req_comp)
{
stbi s;
start_mem(&s,buffer,len);
return stbi_loadf_main(&s,x,y,comp,req_comp);
}
float *stbi_loadf_from_callbacks(stbi_io_callbacks const *clbk, void *user, int *x, int *y, int *comp, int req_comp)
{
stbi s;
start_callbacks(&s, (stbi_io_callbacks *) clbk, user);
return stbi_loadf_main(&s,x,y,comp,req_comp);
}
#ifndef STBI_NO_STDIO
float *stbi_loadf(char const *filename, int *x, int *y, int *comp, int req_comp)
{
FILE *f = fopen(filename, "rb");
float *result;
if (!f) return epf("can't fopen", "Unable to open file");
result = stbi_loadf_from_file(f,x,y,comp,req_comp);
fclose(f);
return result;
}
float *stbi_loadf_from_file(FILE *f, int *x, int *y, int *comp, int req_comp)
{
stbi s;
start_file(&s,f);
return stbi_loadf_main(&s,x,y,comp,req_comp);
}
#endif // !STBI_NO_STDIO
#endif // !STBI_NO_HDR
// these is-hdr-or-not is defined independent of whether STBI_NO_HDR is
// defined, for API simplicity; if STBI_NO_HDR is defined, it always
// reports false!
int stbi_is_hdr_from_memory(stbi_uc const *buffer, int len)
{
#ifndef STBI_NO_HDR
stbi s;
start_mem(&s,buffer,len);
return stbi_hdr_test(&s);
#else
STBI_NOTUSED(buffer);
STBI_NOTUSED(len);
return 0;
#endif
}
#ifndef STBI_NO_STDIO
extern int stbi_is_hdr (char const *filename)
{
FILE *f = fopen(filename, "rb");
int result=0;
if (f) {
result = stbi_is_hdr_from_file(f);
fclose(f);
}
return result;
}
extern int stbi_is_hdr_from_file(FILE *f)
{
#ifndef STBI_NO_HDR
stbi s;
start_file(&s,f);
return stbi_hdr_test(&s);
#else
return 0;
#endif
}
#endif // !STBI_NO_STDIO
extern int stbi_is_hdr_from_callbacks(stbi_io_callbacks const *clbk, void *user)
{
#ifndef STBI_NO_HDR
stbi s;
start_callbacks(&s, (stbi_io_callbacks *) clbk, user);
return stbi_hdr_test(&s);
#else
return 0;
#endif
}
#ifndef STBI_NO_HDR
static float h2l_gamma_i=1.0f/2.2f, h2l_scale_i=1.0f;
static float l2h_gamma=2.2f, l2h_scale=1.0f;
void stbi_hdr_to_ldr_gamma(float gamma) { h2l_gamma_i = 1/gamma; }
void stbi_hdr_to_ldr_scale(float scale) { h2l_scale_i = 1/scale; }
void stbi_ldr_to_hdr_gamma(float gamma) { l2h_gamma = gamma; }
void stbi_ldr_to_hdr_scale(float scale) { l2h_scale = scale; }
#endif
//////////////////////////////////////////////////////////////////////////////
//
// Common code used by all image loaders
//
enum
{
SCAN_load=0,
SCAN_type,
SCAN_header
};
static void refill_buffer(stbi *s)
{
int n = (s->io.read)(s->io_user_data,(char*)s->buffer_start,s->buflen);
if (n == 0) {
// at end of file, treat same as if from memory, but need to handle case
// where s->img_buffer isn't pointing to safe memory, e.g. 0-byte file
s->read_from_callbacks = 0;
s->img_buffer = s->buffer_start;
s->img_buffer_end = s->buffer_start+1;
*s->img_buffer = 0;
} else {
s->img_buffer = s->buffer_start;
s->img_buffer_end = s->buffer_start + n;
}
}
stbi_inline static int get8(stbi *s)
{
if (s->img_buffer < s->img_buffer_end)
return *s->img_buffer++;
if (s->read_from_callbacks) {
refill_buffer(s);
return *s->img_buffer++;
}
return 0;
}
stbi_inline static int at_eof(stbi *s)
{
if (s->io.read) {
if (!(s->io.eof)(s->io_user_data)) return 0;
// if feof() is true, check if buffer = end
// special case: we've only got the special 0 character at the end
if (s->read_from_callbacks == 0) return 1;
}
return s->img_buffer >= s->img_buffer_end;
}
stbi_inline static stbi__uint8 get8u(stbi *s)
{
return (stbi__uint8) get8(s);
}
static void skip(stbi *s, int n)
{
if (s->io.read) {
int blen = (int) (s->img_buffer_end - s->img_buffer);
if (blen < n) {
s->img_buffer = s->img_buffer_end;
(s->io.skip)(s->io_user_data, n - blen);
return;
}
}
s->img_buffer += n;
}
static int getn(stbi *s, stbi_uc *buffer, int n)
{
if (s->io.read) {
int blen = (int) (s->img_buffer_end - s->img_buffer);
if (blen < n) {
int res, count;
memcpy(buffer, s->img_buffer, blen);
count = (s->io.read)(s->io_user_data, (char*) buffer + blen, n - blen);
res = (count == (n-blen));
s->img_buffer = s->img_buffer_end;
return res;
}
}
if (s->img_buffer+n <= s->img_buffer_end) {
memcpy(buffer, s->img_buffer, n);
s->img_buffer += n;
return 1;
} else
return 0;
}
static int get16(stbi *s)
{
int z = get8(s);
return (z << 8) + get8(s);
}
static stbi__uint32 get32(stbi *s)
{
stbi__uint32 z = get16(s);
return (z << 16) + get16(s);
}
static int get16le(stbi *s)
{
int z = get8(s);
return z + (get8(s) << 8);
}
static stbi__uint32 get32le(stbi *s)
{
stbi__uint32 z = get16le(s);
return z + (get16le(s) << 16);
}
//////////////////////////////////////////////////////////////////////////////
//
// generic converter from built-in img_n to req_comp
// individual types do this automatically as much as possible (e.g. jpeg
// does all cases internally since it needs to colorspace convert anyway,
// and it never has alpha, so very few cases ). png can automatically
// interleave an alpha=255 channel, but falls back to this for other cases
//
// assume data buffer is malloced, so malloc a new one and free that one
// only failure mode is malloc failing
static stbi__uint8 compute_y(int r, int g, int b)
{
return (stbi__uint8) (((r*77) + (g*150) + (29*b)) >> 8);
}
static unsigned char *convert_format(unsigned char *data, int img_n, int req_comp, unsigned int x, unsigned int y)
{
int i,j;
unsigned char *good;
if (req_comp == img_n) return data;
assert(req_comp >= 1 && req_comp <= 4);
good = (unsigned char *) malloc(req_comp * x * y);
if (good == NULL) {
free(data);
return epuc("outofmem", "Out of memory");
}
for (j=0; j < (int) y; ++j) {
unsigned char *src = data + j * x * img_n ;
unsigned char *dest = good + j * x * req_comp;
#define COMBO(a,b) ((a)*8+(b))
#define CASE(a,b) case COMBO(a,b): for(i=x-1; i >= 0; --i, src += a, dest += b)
// convert source image with img_n components to one with req_comp components;
// avoid switch per pixel, so use switch per scanline and massive macros
switch (COMBO(img_n, req_comp)) {
CASE(1,2) dest[0]=src[0], dest[1]=255; break;
CASE(1,3) dest[0]=dest[1]=dest[2]=src[0]; break;
CASE(1,4) dest[0]=dest[1]=dest[2]=src[0], dest[3]=255; break;
CASE(2,1) dest[0]=src[0]; break;
CASE(2,3) dest[0]=dest[1]=dest[2]=src[0]; break;
CASE(2,4) dest[0]=dest[1]=dest[2]=src[0], dest[3]=src[1]; break;
CASE(3,4) dest[0]=src[0],dest[1]=src[1],dest[2]=src[2],dest[3]=255; break;
CASE(3,1) dest[0]=compute_y(src[0],src[1],src[2]); break;
CASE(3,2) dest[0]=compute_y(src[0],src[1],src[2]), dest[1] = 255; break;
CASE(4,1) dest[0]=compute_y(src[0],src[1],src[2]); break;
CASE(4,2) dest[0]=compute_y(src[0],src[1],src[2]), dest[1] = src[3]; break;
CASE(4,3) dest[0]=src[0],dest[1]=src[1],dest[2]=src[2]; break;
default: assert(0);
}
#undef CASE
}
free(data);
return good;
}
#ifndef STBI_NO_HDR
static float *ldr_to_hdr(stbi_uc *data, int x, int y, int comp)
{
int i,k,n;
float *output = (float *) malloc(x * y * comp * sizeof(float));
if (output == NULL) { free(data); return epf("outofmem", "Out of memory"); }
// compute number of non-alpha components
if (comp & 1) n = comp; else n = comp-1;
for (i=0; i < x*y; ++i) {
for (k=0; k < n; ++k) {
output[i*comp + k] = (float) pow(data[i*comp+k]/255.0f, l2h_gamma) * l2h_scale;
}
if (k < comp) output[i*comp + k] = data[i*comp+k]/255.0f;
}
free(data);
return output;
}
#define float2int(x) ((int) (x))
static stbi_uc *hdr_to_ldr(float *data, int x, int y, int comp)
{
int i,k,n;
stbi_uc *output = (stbi_uc *) malloc(x * y * comp);
if (output == NULL) { free(data); return epuc("outofmem", "Out of memory"); }
// compute number of non-alpha components
if (comp & 1) n = comp; else n = comp-1;
for (i=0; i < x*y; ++i) {
for (k=0; k < n; ++k) {
float z = (float) pow(data[i*comp+k]*h2l_scale_i, h2l_gamma_i) * 255 + 0.5f;
if (z < 0) z = 0;
if (z > 255) z = 255;
output[i*comp + k] = (stbi__uint8) float2int(z);
}
if (k < comp) {
float z = data[i*comp+k] * 255 + 0.5f;
if (z < 0) z = 0;
if (z > 255) z = 255;
output[i*comp + k] = (stbi__uint8) float2int(z);
}
}
free(data);
return output;
}
#endif
//////////////////////////////////////////////////////////////////////////////
//
// "baseline" JPEG/JFIF decoder (not actually fully baseline implementation)
//
// simple implementation
// - channel subsampling of at most 2 in each dimension
// - doesn't support delayed output of y-dimension
// - simple interface (only one output format: 8-bit interleaved RGB)
// - doesn't try to recover corrupt jpegs
// - doesn't allow partial loading, loading multiple at once
// - still fast on x86 (copying globals into locals doesn't help x86)
// - allocates lots of intermediate memory (full size of all components)
// - non-interleaved case requires this anyway
// - allows good upsampling (see next)
// high-quality
// - upsampled channels are bilinearly interpolated, even across blocks
// - quality integer IDCT derived from IJG's 'slow'
// performance
// - fast huffman; reasonable integer IDCT
// - uses a lot of intermediate memory, could cache poorly
// - load http://nothings.org/remote/anemones.jpg 3 times on 2.8Ghz P4
// stb_jpeg: 1.34 seconds (MSVC6, default release build)
// stb_jpeg: 1.06 seconds (MSVC6, processor = Pentium Pro)
// IJL11.dll: 1.08 seconds (compiled by intel)
// IJG 1998: 0.98 seconds (MSVC6, makefile provided by IJG)
// IJG 1998: 0.95 seconds (MSVC6, makefile + proc=PPro)
// huffman decoding acceleration
#define FAST_BITS 9 // larger handles more cases; smaller stomps less cache
typedef struct
{
stbi__uint8 fast[1 << FAST_BITS];
// weirdly, repacking this into AoS is a 10% speed loss, instead of a win
stbi__uint16 code[256];
stbi__uint8 values[256];
stbi__uint8 size[257];
unsigned int maxcode[18];
int delta[17]; // old 'firstsymbol' - old 'firstcode'
} huffman;
typedef struct
{
#ifdef STBI_SIMD
unsigned short dequant2[4][64];
#endif
stbi *s;
huffman huff_dc[4];
huffman huff_ac[4];
stbi__uint8 dequant[4][64];
// sizes for components, interleaved MCUs
int img_h_max, img_v_max;
int img_mcu_x, img_mcu_y;
int img_mcu_w, img_mcu_h;
// definition of jpeg image component
struct
{
int id;
int h,v;
int tq;
int hd,ha;
int dc_pred;
int x,y,w2,h2;
stbi__uint8 *data;
void *raw_data;
stbi__uint8 *linebuf;
} img_comp[4];
stbi__uint32 code_buffer; // jpeg entropy-coded buffer
int code_bits; // number of valid bits
unsigned char marker; // marker seen while filling entropy buffer
int nomore; // flag if we saw a marker so must stop
int scan_n, order[4];
int restart_interval, todo;
} jpeg;
static int build_huffman(huffman *h, int *count)
{
int i,j,k=0,code;
// build size list for each symbol (from JPEG spec)
for (i=0; i < 16; ++i)
for (j=0; j < count[i]; ++j)
h->size[k++] = (stbi__uint8) (i+1);
h->size[k] = 0;
// compute actual symbols (from jpeg spec)
code = 0;
k = 0;
for(j=1; j <= 16; ++j) {
// compute delta to add to code to compute symbol id
h->delta[j] = k - code;
if (h->size[k] == j) {
while (h->size[k] == j)
h->code[k++] = (stbi__uint16) (code++);
if (code-1 >= (1 << j)) return e("bad code lengths","Corrupt JPEG");
}
// compute largest code + 1 for this size, preshifted as needed later
h->maxcode[j] = code << (16-j);
code <<= 1;
}
h->maxcode[j] = 0xffffffff;
// build non-spec acceleration table; 255 is flag for not-accelerated
memset(h->fast, 255, 1 << FAST_BITS);
for (i=0; i < k; ++i) {
int s = h->size[i];
if (s <= FAST_BITS) {
int c = h->code[i] << (FAST_BITS-s);
int m = 1 << (FAST_BITS-s);
for (j=0; j < m; ++j) {
h->fast[c+j] = (stbi__uint8) i;
}
}
}
return 1;
}
static void grow_buffer_unsafe(jpeg *j)
{
do {
int b = j->nomore ? 0 : get8(j->s);
if (b == 0xff) {
int c = get8(j->s);
if (c != 0) {
j->marker = (unsigned char) c;
j->nomore = 1;
return;
}
}
j->code_buffer |= b << (24 - j->code_bits);
j->code_bits += 8;
} while (j->code_bits <= 24);
}
// (1 << n) - 1
static stbi__uint32 bmask[17]={0,1,3,7,15,31,63,127,255,511,1023,2047,4095,8191,16383,32767,65535};
// decode a jpeg huffman value from the bitstream
stbi_inline static int decode(jpeg *j, huffman *h)
{
unsigned int temp;
int c,k;
if (j->code_bits < 16) grow_buffer_unsafe(j);
// look at the top FAST_BITS and determine what symbol ID it is,
// if the code is <= FAST_BITS
c = (j->code_buffer >> (32 - FAST_BITS)) & ((1 << FAST_BITS)-1);
k = h->fast[c];
if (k < 255) {
int s = h->size[k];
if (s > j->code_bits)
return -1;
j->code_buffer <<= s;
j->code_bits -= s;
return h->values[k];
}
// naive test is to shift the code_buffer down so k bits are
// valid, then test against maxcode. To speed this up, we've
// preshifted maxcode left so that it has (16-k) 0s at the
// end; in other words, regardless of the number of bits, it
// wants to be compared against something shifted to have 16;
// that way we don't need to shift inside the loop.
temp = j->code_buffer >> 16;
for (k=FAST_BITS+1 ; ; ++k)
if (temp < h->maxcode[k])
break;
if (k == 17) {
// error! code not found
j->code_bits -= 16;
return -1;
}
if (k > j->code_bits)
return -1;
// convert the huffman code to the symbol id
c = ((j->code_buffer >> (32 - k)) & bmask[k]) + h->delta[k];
assert((((j->code_buffer) >> (32 - h->size[c])) & bmask[h->size[c]]) == h->code[c]);
// convert the id to a symbol
j->code_bits -= k;
j->code_buffer <<= k;
return h->values[c];
}
// combined JPEG 'receive' and JPEG 'extend', since baseline
// always extends everything it receives.
stbi_inline static int extend_receive(jpeg *j, int n)
{
unsigned int m = 1 << (n-1);
unsigned int k;
if (j->code_bits < n) grow_buffer_unsafe(j);
#if 1
k = stbi_lrot(j->code_buffer, n);
j->code_buffer = k & ~bmask[n];
k &= bmask[n];
j->code_bits -= n;
#else
k = (j->code_buffer >> (32 - n)) & bmask[n];
j->code_bits -= n;
j->code_buffer <<= n;
#endif
// the following test is probably a random branch that won't
// predict well. I tried to table accelerate it but failed.
// maybe it's compiling as a conditional move?
if (k < m)
return (-1 << n) + k + 1;
else
return k;
}
// given a value that's at position X in the zigzag stream,
// where does it appear in the 8x8 matrix coded as row-major?
static stbi__uint8 dezigzag[64+15] =
{
0, 1, 8, 16, 9, 2, 3, 10,
17, 24, 32, 25, 18, 11, 4, 5,
12, 19, 26, 33, 40, 48, 41, 34,
27, 20, 13, 6, 7, 14, 21, 28,
35, 42, 49, 56, 57, 50, 43, 36,
29, 22, 15, 23, 30, 37, 44, 51,
58, 59, 52, 45, 38, 31, 39, 46,
53, 60, 61, 54, 47, 55, 62, 63,
// let corrupt input sample past end
63, 63, 63, 63, 63, 63, 63, 63,
63, 63, 63, 63, 63, 63, 63
};
// decode one 64-entry block--
static int decode_block(jpeg *j, short data[64], huffman *hdc, huffman *hac, int b)
{
int diff,dc,k;
int t = decode(j, hdc);
if (t < 0) return e("bad huffman code","Corrupt JPEG");
// 0 all the ac values now so we can do it 32-bits at a time
memset(data,0,64*sizeof(data[0]));
diff = t ? extend_receive(j, t) : 0;
dc = j->img_comp[b].dc_pred + diff;
j->img_comp[b].dc_pred = dc;
data[0] = (short) dc;
// decode AC components, see JPEG spec
k = 1;
do {
int r,s;
int rs = decode(j, hac);
if (rs < 0) return e("bad huffman code","Corrupt JPEG");
s = rs & 15;
r = rs >> 4;
if (s == 0) {
if (rs != 0xf0) break; // end block
k += 16;
} else {
k += r;
// decode into unzigzag'd location
data[dezigzag[k++]] = (short) extend_receive(j,s);
}
} while (k < 64);
return 1;
}
// take a -128..127 value and clamp it and convert to 0..255
stbi_inline static stbi__uint8 clamp(int x)
{
// trick to use a single test to catch both cases
if ((unsigned int) x > 255) {
if (x < 0) return 0;
if (x > 255) return 255;
}
return (stbi__uint8) x;
}
#define f2f(x) (int) (((x) * 4096 + 0.5))
#define fsh(x) ((x) << 12)
// derived from jidctint -- DCT_ISLOW
#define IDCT_1D(s0,s1,s2,s3,s4,s5,s6,s7) \
int t0,t1,t2,t3,p1,p2,p3,p4,p5,x0,x1,x2,x3; \
p2 = s2; \
p3 = s6; \
p1 = (p2+p3) * f2f(0.5411961f); \
t2 = p1 + p3*f2f(-1.847759065f); \
t3 = p1 + p2*f2f( 0.765366865f); \
p2 = s0; \
p3 = s4; \
t0 = fsh(p2+p3); \
t1 = fsh(p2-p3); \
x0 = t0+t3; \
x3 = t0-t3; \
x1 = t1+t2; \
x2 = t1-t2; \
t0 = s7; \
t1 = s5; \
t2 = s3; \
t3 = s1; \
p3 = t0+t2; \
p4 = t1+t3; \
p1 = t0+t3; \
p2 = t1+t2; \
p5 = (p3+p4)*f2f( 1.175875602f); \
t0 = t0*f2f( 0.298631336f); \
t1 = t1*f2f( 2.053119869f); \
t2 = t2*f2f( 3.072711026f); \
t3 = t3*f2f( 1.501321110f); \
p1 = p5 + p1*f2f(-0.899976223f); \
p2 = p5 + p2*f2f(-2.562915447f); \
p3 = p3*f2f(-1.961570560f); \
p4 = p4*f2f(-0.390180644f); \
t3 += p1+p4; \
t2 += p2+p3; \
t1 += p2+p4; \
t0 += p1+p3;
#ifdef STBI_SIMD
typedef unsigned short stbi_dequantize_t;
#else
typedef stbi__uint8 stbi_dequantize_t;
#endif
// .344 seconds on 3*anemones.jpg
static void idct_block(stbi__uint8 *out, int out_stride, short data[64], stbi_dequantize_t *dequantize)
{
int i,val[64],*v=val;
stbi_dequantize_t *dq = dequantize;
stbi__uint8 *o;
short *d = data;
// columns
for (i=0; i < 8; ++i,++d,++dq, ++v) {
// if all zeroes, shortcut -- this avoids dequantizing 0s and IDCTing
if (d[ 8]==0 && d[16]==0 && d[24]==0 && d[32]==0
&& d[40]==0 && d[48]==0 && d[56]==0) {
// no shortcut 0 seconds
// (1|2|3|4|5|6|7)==0 0 seconds
// all separate -0.047 seconds
// 1 && 2|3 && 4|5 && 6|7: -0.047 seconds
int dcterm = d[0] * dq[0] << 2;
v[0] = v[8] = v[16] = v[24] = v[32] = v[40] = v[48] = v[56] = dcterm;
} else {
IDCT_1D(d[ 0]*dq[ 0],d[ 8]*dq[ 8],d[16]*dq[16],d[24]*dq[24],
d[32]*dq[32],d[40]*dq[40],d[48]*dq[48],d[56]*dq[56])
// constants scaled things up by 1<<12; let's bring them back
// down, but keep 2 extra bits of precision
x0 += 512; x1 += 512; x2 += 512; x3 += 512;
v[ 0] = (x0+t3) >> 10;
v[56] = (x0-t3) >> 10;
v[ 8] = (x1+t2) >> 10;
v[48] = (x1-t2) >> 10;
v[16] = (x2+t1) >> 10;
v[40] = (x2-t1) >> 10;
v[24] = (x3+t0) >> 10;
v[32] = (x3-t0) >> 10;
}
}
for (i=0, v=val, o=out; i < 8; ++i,v+=8,o+=out_stride) {
// no fast case since the first 1D IDCT spread components out
IDCT_1D(v[0],v[1],v[2],v[3],v[4],v[5],v[6],v[7])
// constants scaled things up by 1<<12, plus we had 1<<2 from first
// loop, plus horizontal and vertical each scale by sqrt(8) so together
// we've got an extra 1<<3, so 1<<17 total we need to remove.
// so we want to round that, which means adding 0.5 * 1<<17,
// aka 65536. Also, we'll end up with -128 to 127 that we want
// to encode as 0..255 by adding 128, so we'll add that before the shift
x0 += 65536 + (128<<17);
x1 += 65536 + (128<<17);
x2 += 65536 + (128<<17);
x3 += 65536 + (128<<17);
// tried computing the shifts into temps, or'ing the temps to see
// if any were out of range, but that was slower
o[0] = clamp((x0+t3) >> 17);
o[7] = clamp((x0-t3) >> 17);
o[1] = clamp((x1+t2) >> 17);
o[6] = clamp((x1-t2) >> 17);
o[2] = clamp((x2+t1) >> 17);
o[5] = clamp((x2-t1) >> 17);
o[3] = clamp((x3+t0) >> 17);
o[4] = clamp((x3-t0) >> 17);
}
}
#ifdef STBI_SIMD
static stbi_idct_8x8 stbi_idct_installed = idct_block;
void stbi_install_idct(stbi_idct_8x8 func)
{
stbi_idct_installed = func;
}
#endif
#define MARKER_none 0xff
// if there's a pending marker from the entropy stream, return that
// otherwise, fetch from the stream and get a marker. if there's no
// marker, return 0xff, which is never a valid marker value
static stbi__uint8 get_marker(jpeg *j)
{
stbi__uint8 x;
if (j->marker != MARKER_none) { x = j->marker; j->marker = MARKER_none; return x; }
x = get8u(j->s);
if (x != 0xff) return MARKER_none;
while (x == 0xff)
x = get8u(j->s);
return x;
}
// in each scan, we'll have scan_n components, and the order
// of the components is specified by order[]
#define RESTART(x) ((x) >= 0xd0 && (x) <= 0xd7)
// after a restart interval, reset the entropy decoder and
// the dc prediction
static void reset(jpeg *j)
{
j->code_bits = 0;
j->code_buffer = 0;
j->nomore = 0;
j->img_comp[0].dc_pred = j->img_comp[1].dc_pred = j->img_comp[2].dc_pred = 0;
j->marker = MARKER_none;
j->todo = j->restart_interval ? j->restart_interval : 0x7fffffff;
// no more than 1<<31 MCUs if no restart_interal? that's plenty safe,
// since we don't even allow 1<<30 pixels
}
static int parse_entropy_coded_data(jpeg *z)
{
reset(z);
if (z->scan_n == 1) {
int i,j;
#ifdef STBI_SIMD
__declspec(align(16))
#endif
short data[64];
int n = z->order[0];
// non-interleaved data, we just need to process one block at a time,
// in trivial scanline order
// number of blocks to do just depends on how many actual "pixels" this
// component has, independent of interleaved MCU blocking and such
int w = (z->img_comp[n].x+7) >> 3;
int h = (z->img_comp[n].y+7) >> 3;
for (j=0; j < h; ++j) {
for (i=0; i < w; ++i) {
if (!decode_block(z, data, z->huff_dc+z->img_comp[n].hd, z->huff_ac+z->img_comp[n].ha, n)) return 0;
#ifdef STBI_SIMD
stbi_idct_installed(z->img_comp[n].data+z->img_comp[n].w2*j*8+i*8, z->img_comp[n].w2, data, z->dequant2[z->img_comp[n].tq]);
#else
idct_block(z->img_comp[n].data+z->img_comp[n].w2*j*8+i*8, z->img_comp[n].w2, data, z->dequant[z->img_comp[n].tq]);
#endif
// every data block is an MCU, so countdown the restart interval
if (--z->todo <= 0) {
if (z->code_bits < 24) grow_buffer_unsafe(z);
// if it's NOT a restart, then just bail, so we get corrupt data
// rather than no data
if (!RESTART(z->marker)) return 1;
reset(z);
}
}
}
} else { // interleaved!
int i,j,k,x,y;
short data[64];
for (j=0; j < z->img_mcu_y; ++j) {
for (i=0; i < z->img_mcu_x; ++i) {
// scan an interleaved mcu... process scan_n components in order
for (k=0; k < z->scan_n; ++k) {
int n = z->order[k];
// scan out an mcu's worth of this component; that's just determined
// by the basic H and V specified for the component
for (y=0; y < z->img_comp[n].v; ++y) {
for (x=0; x < z->img_comp[n].h; ++x) {
int x2 = (i*z->img_comp[n].h + x)*8;
int y2 = (j*z->img_comp[n].v + y)*8;
if (!decode_block(z, data, z->huff_dc+z->img_comp[n].hd, z->huff_ac+z->img_comp[n].ha, n)) return 0;
#ifdef STBI_SIMD
stbi_idct_installed(z->img_comp[n].data+z->img_comp[n].w2*y2+x2, z->img_comp[n].w2, data, z->dequant2[z->img_comp[n].tq]);
#else
idct_block(z->img_comp[n].data+z->img_comp[n].w2*y2+x2, z->img_comp[n].w2, data, z->dequant[z->img_comp[n].tq]);
#endif
}
}
}
// after all interleaved components, that's an interleaved MCU,
// so now count down the restart interval
if (--z->todo <= 0) {
if (z->code_bits < 24) grow_buffer_unsafe(z);
// if it's NOT a restart, then just bail, so we get corrupt data
// rather than no data
if (!RESTART(z->marker)) return 1;
reset(z);
}
}
}
}
return 1;
}
static int process_marker(jpeg *z, int m)
{
int L;
switch (m) {
case MARKER_none: // no marker found
return e("expected marker","Corrupt JPEG");
case 0xC2: // SOF - progressive
return e("progressive jpeg","JPEG format not supported (progressive)");
case 0xDD: // DRI - specify restart interval
if (get16(z->s) != 4) return e("bad DRI len","Corrupt JPEG");
z->restart_interval = get16(z->s);
return 1;
case 0xDB: // DQT - define quantization table
L = get16(z->s)-2;
while (L > 0) {
int q = get8(z->s);
int p = q >> 4;
int t = q & 15,i;
if (p != 0) return e("bad DQT type","Corrupt JPEG");
if (t > 3) return e("bad DQT table","Corrupt JPEG");
for (i=0; i < 64; ++i)
z->dequant[t][dezigzag[i]] = get8u(z->s);
#ifdef STBI_SIMD
for (i=0; i < 64; ++i)
z->dequant2[t][i] = z->dequant[t][i];
#endif
L -= 65;
}
return L==0;
case 0xC4: // DHT - define huffman table
L = get16(z->s)-2;
while (L > 0) {
stbi__uint8 *v;
int sizes[16],i,n=0;
int q = get8(z->s);
int tc = q >> 4;
int th = q & 15;
if (tc > 1 || th > 3) return e("bad DHT header","Corrupt JPEG");
for (i=0; i < 16; ++i) {
sizes[i] = get8(z->s);
n += sizes[i];
}
L -= 17;
if (tc == 0) {
if (!build_huffman(z->huff_dc+th, sizes)) return 0;
v = z->huff_dc[th].values;
} else {
if (!build_huffman(z->huff_ac+th, sizes)) return 0;
v = z->huff_ac[th].values;
}
for (i=0; i < n; ++i)
v[i] = get8u(z->s);
L -= n;
}
return L==0;
}
// check for comment block or APP blocks
if ((m >= 0xE0 && m <= 0xEF) || m == 0xFE) {
skip(z->s, get16(z->s)-2);
return 1;
}
return 0;
}
// after we see SOS
static int process_scan_header(jpeg *z)
{
int i;
int Ls = get16(z->s);
z->scan_n = get8(z->s);
if (z->scan_n < 1 || z->scan_n > 4 || z->scan_n > (int) z->s->img_n) return e("bad SOS component count","Corrupt JPEG");
if (Ls != 6+2*z->scan_n) return e("bad SOS len","Corrupt JPEG");
for (i=0; i < z->scan_n; ++i) {
int id = get8(z->s), which;
int q = get8(z->s);
for (which = 0; which < z->s->img_n; ++which)
if (z->img_comp[which].id == id)
break;
if (which == z->s->img_n) return 0;
z->img_comp[which].hd = q >> 4; if (z->img_comp[which].hd > 3) return e("bad DC huff","Corrupt JPEG");
z->img_comp[which].ha = q & 15; if (z->img_comp[which].ha > 3) return e("bad AC huff","Corrupt JPEG");
z->order[i] = which;
}
if (get8(z->s) != 0) return e("bad SOS","Corrupt JPEG");
get8(z->s); // should be 63, but might be 0
if (get8(z->s) != 0) return e("bad SOS","Corrupt JPEG");
return 1;
}
static int process_frame_header(jpeg *z, int scan)
{
stbi *s = z->s;
int Lf,p,i,q, h_max=1,v_max=1,c;
Lf = get16(s); if (Lf < 11) return e("bad SOF len","Corrupt JPEG"); // JPEG
p = get8(s); if (p != 8) return e("only 8-bit","JPEG format not supported: 8-bit only"); // JPEG baseline
s->img_y = get16(s); if (s->img_y == 0) return e("no header height", "JPEG format not supported: delayed height"); // Legal, but we don't handle it--but neither does IJG
s->img_x = get16(s); if (s->img_x == 0) return e("0 width","Corrupt JPEG"); // JPEG requires
c = get8(s);
if (c != 3 && c != 1) return e("bad component count","Corrupt JPEG"); // JFIF requires
s->img_n = c;
for (i=0; i < c; ++i) {
z->img_comp[i].data = NULL;
z->img_comp[i].linebuf = NULL;
}
if (Lf != 8+3*s->img_n) return e("bad SOF len","Corrupt JPEG");
for (i=0; i < s->img_n; ++i) {
z->img_comp[i].id = get8(s);
if (z->img_comp[i].id != i+1) // JFIF requires
if (z->img_comp[i].id != i) // some version of jpegtran outputs non-JFIF-compliant files!
return e("bad component ID","Corrupt JPEG");
q = get8(s);
z->img_comp[i].h = (q >> 4); if (!z->img_comp[i].h || z->img_comp[i].h > 4) return e("bad H","Corrupt JPEG");
z->img_comp[i].v = q & 15; if (!z->img_comp[i].v || z->img_comp[i].v > 4) return e("bad V","Corrupt JPEG");
z->img_comp[i].tq = get8(s); if (z->img_comp[i].tq > 3) return e("bad TQ","Corrupt JPEG");
}
if (scan != SCAN_load) return 1;
if ((1 << 30) / s->img_x / s->img_n < s->img_y) return e("too large", "Image too large to decode");
for (i=0; i < s->img_n; ++i) {
if (z->img_comp[i].h > h_max) h_max = z->img_comp[i].h;
if (z->img_comp[i].v > v_max) v_max = z->img_comp[i].v;
}
// compute interleaved mcu info
z->img_h_max = h_max;
z->img_v_max = v_max;
z->img_mcu_w = h_max * 8;
z->img_mcu_h = v_max * 8;
z->img_mcu_x = (s->img_x + z->img_mcu_w-1) / z->img_mcu_w;
z->img_mcu_y = (s->img_y + z->img_mcu_h-1) / z->img_mcu_h;
for (i=0; i < s->img_n; ++i) {
// number of effective pixels (e.g. for non-interleaved MCU)
z->img_comp[i].x = (s->img_x * z->img_comp[i].h + h_max-1) / h_max;
z->img_comp[i].y = (s->img_y * z->img_comp[i].v + v_max-1) / v_max;
// to simplify generation, we'll allocate enough memory to decode
// the bogus oversized data from using interleaved MCUs and their
// big blocks (e.g. a 16x16 iMCU on an image of width 33); we won't
// discard the extra data until colorspace conversion
z->img_comp[i].w2 = z->img_mcu_x * z->img_comp[i].h * 8;
z->img_comp[i].h2 = z->img_mcu_y * z->img_comp[i].v * 8;
z->img_comp[i].raw_data = malloc(z->img_comp[i].w2 * z->img_comp[i].h2+15);
if (z->img_comp[i].raw_data == NULL) {
for(--i; i >= 0; --i) {
free(z->img_comp[i].raw_data);
z->img_comp[i].data = NULL;
}
return e("outofmem", "Out of memory");
}
// align blocks for installable-idct using mmx/sse
z->img_comp[i].data = (stbi__uint8*) (((size_t) z->img_comp[i].raw_data + 15) & ~15);
z->img_comp[i].linebuf = NULL;
}
return 1;
}
// use comparisons since in some cases we handle more than one case (e.g. SOF)
#define DNL(x) ((x) == 0xdc)
#define SOI(x) ((x) == 0xd8)
#define EOI(x) ((x) == 0xd9)
#define SOF(x) ((x) == 0xc0 || (x) == 0xc1)
#define SOS(x) ((x) == 0xda)
static int decode_jpeg_header(jpeg *z, int scan)
{
int m;
z->marker = MARKER_none; // initialize cached marker to empty
m = get_marker(z);
if (!SOI(m)) return e("no SOI","Corrupt JPEG");
if (scan == SCAN_type) return 1;
m = get_marker(z);
while (!SOF(m)) {
if (!process_marker(z,m)) return 0;
m = get_marker(z);
while (m == MARKER_none) {
// some files have extra padding after their blocks, so ok, we'll scan
if (at_eof(z->s)) return e("no SOF", "Corrupt JPEG");
m = get_marker(z);
}
}
if (!process_frame_header(z, scan)) return 0;
return 1;
}
static int decode_jpeg_image(jpeg *j)
{
int m;
j->restart_interval = 0;
if (!decode_jpeg_header(j, SCAN_load)) return 0;
m = get_marker(j);
while (!EOI(m)) {
if (SOS(m)) {
if (!process_scan_header(j)) return 0;
if (!parse_entropy_coded_data(j)) return 0;
if (j->marker == MARKER_none ) {
// handle 0s at the end of image data from IP Kamera 9060
while (!at_eof(j->s)) {
int x = get8(j->s);
if (x == 255) {
j->marker = get8u(j->s);
break;
} else if (x != 0) {
return 0;
}
}
// if we reach eof without hitting a marker, get_marker() below will fail and we'll eventually return 0
}
} else {
if (!process_marker(j, m)) return 0;
}
m = get_marker(j);
}
return 1;
}
// static jfif-centered resampling (across block boundaries)
typedef stbi__uint8 *(*resample_row_func)(stbi__uint8 *out, stbi__uint8 *in0, stbi__uint8 *in1,
int w, int hs);
#define div4(x) ((stbi__uint8) ((x) >> 2))
static stbi__uint8 *resample_row_1(stbi__uint8 *out, stbi__uint8 *in_near, stbi__uint8 *in_far, int w, int hs)
{
STBI_NOTUSED(out);
STBI_NOTUSED(in_far);
STBI_NOTUSED(w);
STBI_NOTUSED(hs);
return in_near;
}
static stbi__uint8* resample_row_v_2(stbi__uint8 *out, stbi__uint8 *in_near, stbi__uint8 *in_far, int w, int hs)
{
// need to generate two samples vertically for every one in input
int i;
STBI_NOTUSED(hs);
for (i=0; i < w; ++i)
out[i] = div4(3*in_near[i] + in_far[i] + 2);
return out;
}
static stbi__uint8* resample_row_h_2(stbi__uint8 *out, stbi__uint8 *in_near, stbi__uint8 *in_far, int w, int hs)
{
// need to generate two samples horizontally for every one in input
int i;
stbi__uint8 *input = in_near;
if (w == 1) {
// if only one sample, can't do any interpolation
out[0] = out[1] = input[0];
return out;
}
out[0] = input[0];
out[1] = div4(input[0]*3 + input[1] + 2);
for (i=1; i < w-1; ++i) {
int n = 3*input[i]+2;
out[i*2+0] = div4(n+input[i-1]);
out[i*2+1] = div4(n+input[i+1]);
}
out[i*2+0] = div4(input[w-2]*3 + input[w-1] + 2);
out[i*2+1] = input[w-1];
STBI_NOTUSED(in_far);
STBI_NOTUSED(hs);
return out;
}
#define div16(x) ((stbi__uint8) ((x) >> 4))
static stbi__uint8 *resample_row_hv_2(stbi__uint8 *out, stbi__uint8 *in_near, stbi__uint8 *in_far, int w, int hs)
{
// need to generate 2x2 samples for every one in input
int i,t0,t1;
if (w == 1) {
out[0] = out[1] = div4(3*in_near[0] + in_far[0] + 2);
return out;
}
t1 = 3*in_near[0] + in_far[0];
out[0] = div4(t1+2);
for (i=1; i < w; ++i) {
t0 = t1;
t1 = 3*in_near[i]+in_far[i];
out[i*2-1] = div16(3*t0 + t1 + 8);
out[i*2 ] = div16(3*t1 + t0 + 8);
}
out[w*2-1] = div4(t1+2);
STBI_NOTUSED(hs);
return out;
}
static stbi__uint8 *resample_row_generic(stbi__uint8 *out, stbi__uint8 *in_near, stbi__uint8 *in_far, int w, int hs)
{
// resample with nearest-neighbor
int i,j;
STBI_NOTUSED(in_far);
for (i=0; i < w; ++i)
for (j=0; j < hs; ++j)
out[i*hs+j] = in_near[i];
return out;
}
#define float2fixed(x) ((int) ((x) * 65536 + 0.5))
// 0.38 seconds on 3*anemones.jpg (0.25 with processor = Pro)
// VC6 without processor=Pro is generating multiple LEAs per multiply!
static void YCbCr_to_RGB_row(stbi__uint8 *out, const stbi__uint8 *y, const stbi__uint8 *pcb, const stbi__uint8 *pcr, int count, int step)
{
int i;
for (i=0; i < count; ++i) {
int y_fixed = (y[i] << 16) + 32768; // rounding
int r,g,b;
int cr = pcr[i] - 128;
int cb = pcb[i] - 128;
r = y_fixed + cr*float2fixed(1.40200f);
g = y_fixed - cr*float2fixed(0.71414f) - cb*float2fixed(0.34414f);
b = y_fixed + cb*float2fixed(1.77200f);
r >>= 16;
g >>= 16;
b >>= 16;
if ((unsigned) r > 255) { if (r < 0) r = 0; else r = 255; }
if ((unsigned) g > 255) { if (g < 0) g = 0; else g = 255; }
if ((unsigned) b > 255) { if (b < 0) b = 0; else b = 255; }
out[0] = (stbi__uint8)r;
out[1] = (stbi__uint8)g;
out[2] = (stbi__uint8)b;
out[3] = 255;
out += step;
}
}
#ifdef STBI_SIMD
static stbi_YCbCr_to_RGB_run stbi_YCbCr_installed = YCbCr_to_RGB_row;
void stbi_install_YCbCr_to_RGB(stbi_YCbCr_to_RGB_run func)
{
stbi_YCbCr_installed = func;
}
#endif
// clean up the temporary component buffers
static void cleanup_jpeg(jpeg *j)
{
int i;
for (i=0; i < j->s->img_n; ++i) {
if (j->img_comp[i].data) {
free(j->img_comp[i].raw_data);
j->img_comp[i].data = NULL;
}
if (j->img_comp[i].linebuf) {
free(j->img_comp[i].linebuf);
j->img_comp[i].linebuf = NULL;
}
}
}
typedef struct
{
resample_row_func resample;
stbi__uint8 *line0,*line1;
int hs,vs; // expansion factor in each axis
int w_lores; // horizontal pixels pre-expansion
int ystep; // how far through vertical expansion we are
int ypos; // which pre-expansion row we're on
} stbi_resample;
static stbi__uint8 *load_jpeg_image(jpeg *z, int *out_x, int *out_y, int *comp, int req_comp)
{
int n, decode_n;
// validate req_comp
if (req_comp < 0 || req_comp > 4) return epuc("bad req_comp", "Internal error");
z->s->img_n = 0;
// load a jpeg image from whichever source
if (!decode_jpeg_image(z)) { cleanup_jpeg(z); return NULL; }
// determine actual number of components to generate
n = req_comp ? req_comp : z->s->img_n;
if (z->s->img_n == 3 && n < 3)
decode_n = 1;
else
decode_n = z->s->img_n;
// resample and color-convert
{
int k;
unsigned int i,j;
stbi__uint8 *output;
stbi__uint8 *coutput[4];
stbi_resample res_comp[4];
for (k=0; k < decode_n; ++k) {
stbi_resample *r = &res_comp[k];
// allocate line buffer big enough for upsampling off the edges
// with upsample factor of 4
z->img_comp[k].linebuf = (stbi__uint8 *) malloc(z->s->img_x + 3);
if (!z->img_comp[k].linebuf) { cleanup_jpeg(z); return epuc("outofmem", "Out of memory"); }
r->hs = z->img_h_max / z->img_comp[k].h;
r->vs = z->img_v_max / z->img_comp[k].v;
r->ystep = r->vs >> 1;
r->w_lores = (z->s->img_x + r->hs-1) / r->hs;
r->ypos = 0;
r->line0 = r->line1 = z->img_comp[k].data;
if (r->hs == 1 && r->vs == 1) r->resample = resample_row_1;
else if (r->hs == 1 && r->vs == 2) r->resample = resample_row_v_2;
else if (r->hs == 2 && r->vs == 1) r->resample = resample_row_h_2;
else if (r->hs == 2 && r->vs == 2) r->resample = resample_row_hv_2;
else r->resample = resample_row_generic;
}
// can't error after this so, this is safe
output = (stbi__uint8 *) malloc(n * z->s->img_x * z->s->img_y + 1);
if (!output) { cleanup_jpeg(z); return epuc("outofmem", "Out of memory"); }
// now go ahead and resample
for (j=0; j < z->s->img_y; ++j) {
stbi__uint8 *out = output + n * z->s->img_x * j;
for (k=0; k < decode_n; ++k) {
stbi_resample *r = &res_comp[k];
int y_bot = r->ystep >= (r->vs >> 1);
coutput[k] = r->resample(z->img_comp[k].linebuf,
y_bot ? r->line1 : r->line0,
y_bot ? r->line0 : r->line1,
r->w_lores, r->hs);
if (++r->ystep >= r->vs) {
r->ystep = 0;
r->line0 = r->line1;
if (++r->ypos < z->img_comp[k].y)
r->line1 += z->img_comp[k].w2;
}
}
if (n >= 3) {
stbi__uint8 *y = coutput[0];
if (z->s->img_n == 3) {
#ifdef STBI_SIMD
stbi_YCbCr_installed(out, y, coutput[1], coutput[2], z->s->img_x, n);
#else
YCbCr_to_RGB_row(out, y, coutput[1], coutput[2], z->s->img_x, n);
#endif
} else
for (i=0; i < z->s->img_x; ++i) {
out[0] = out[1] = out[2] = y[i];
out[3] = 255; // not used if n==3
out += n;
}
} else {
stbi__uint8 *y = coutput[0];
if (n == 1)
for (i=0; i < z->s->img_x; ++i) out[i] = y[i];
else
for (i=0; i < z->s->img_x; ++i) *out++ = y[i], *out++ = 255;
}
}
cleanup_jpeg(z);
*out_x = z->s->img_x;
*out_y = z->s->img_y;
if (comp) *comp = z->s->img_n; // report original components, not output
return output;
}
}
static unsigned char *stbi_jpeg_load(stbi *s, int *x, int *y, int *comp, int req_comp)
{
jpeg j;
j.s = s;
return load_jpeg_image(&j, x,y,comp,req_comp);
}
static int stbi_jpeg_test(stbi *s)
{
int r;
jpeg j;
j.s = s;
r = decode_jpeg_header(&j, SCAN_type);
stbi_rewind(s);
return r;
}
static int stbi_jpeg_info_raw(jpeg *j, int *x, int *y, int *comp)
{
if (!decode_jpeg_header(j, SCAN_header)) {
stbi_rewind( j->s );
return 0;
}
if (x) *x = j->s->img_x;
if (y) *y = j->s->img_y;
if (comp) *comp = j->s->img_n;
return 1;
}
static int stbi_jpeg_info(stbi *s, int *x, int *y, int *comp)
{
jpeg j;
j.s = s;
return stbi_jpeg_info_raw(&j, x, y, comp);
}
// public domain zlib decode v0.2 Sean Barrett 2006-11-18
// simple implementation
// - all input must be provided in an upfront buffer
// - all output is written to a single output buffer (can malloc/realloc)
// performance
// - fast huffman
// fast-way is faster to check than jpeg huffman, but slow way is slower
#define ZFAST_BITS 9 // accelerate all cases in default tables
#define ZFAST_MASK ((1 << ZFAST_BITS) - 1)
// zlib-style huffman encoding
// (jpegs packs from left, zlib from right, so can't share code)
typedef struct
{
stbi__uint16 fast[1 << ZFAST_BITS];
stbi__uint16 firstcode[16];
int maxcode[17];
stbi__uint16 firstsymbol[16];
stbi__uint8 size[288];
stbi__uint16 value[288];
} zhuffman;
stbi_inline static int bitreverse16(int n)
{
n = ((n & 0xAAAA) >> 1) | ((n & 0x5555) << 1);
n = ((n & 0xCCCC) >> 2) | ((n & 0x3333) << 2);
n = ((n & 0xF0F0) >> 4) | ((n & 0x0F0F) << 4);
n = ((n & 0xFF00) >> 8) | ((n & 0x00FF) << 8);
return n;
}
stbi_inline static int bit_reverse(int v, int bits)
{
assert(bits <= 16);
// to bit reverse n bits, reverse 16 and shift
// e.g. 11 bits, bit reverse and shift away 5
return bitreverse16(v) >> (16-bits);
}
static int zbuild_huffman(zhuffman *z, stbi__uint8 *sizelist, int num)
{
int i,k=0;
int code, next_code[16], sizes[17];
// DEFLATE spec for generating codes
memset(sizes, 0, sizeof(sizes));
memset(z->fast, 255, sizeof(z->fast));
for (i=0; i < num; ++i)
++sizes[sizelist[i]];
sizes[0] = 0;
for (i=1; i < 16; ++i)
assert(sizes[i] <= (1 << i));
code = 0;
for (i=1; i < 16; ++i) {
next_code[i] = code;
z->firstcode[i] = (stbi__uint16) code;
z->firstsymbol[i] = (stbi__uint16) k;
code = (code + sizes[i]);
if (sizes[i])
if (code-1 >= (1 << i)) return e("bad codelengths","Corrupt JPEG");
z->maxcode[i] = code << (16-i); // preshift for inner loop
code <<= 1;
k += sizes[i];
}
z->maxcode[16] = 0x10000; // sentinel
for (i=0; i < num; ++i) {
int s = sizelist[i];
if (s) {
int c = next_code[s] - z->firstcode[s] + z->firstsymbol[s];
z->size[c] = (stbi__uint8)s;
z->value[c] = (stbi__uint16)i;
if (s <= ZFAST_BITS) {
int k = bit_reverse(next_code[s],s);
while (k < (1 << ZFAST_BITS)) {
z->fast[k] = (stbi__uint16) c;
k += (1 << s);
}
}
++next_code[s];
}
}
return 1;
}
// zlib-from-memory implementation for PNG reading
// because PNG allows splitting the zlib stream arbitrarily,
// and it's annoying structurally to have PNG call ZLIB call PNG,
// we require PNG read all the IDATs and combine them into a single
// memory buffer
typedef struct
{
stbi__uint8 *zbuffer, *zbuffer_end;
int num_bits;
stbi__uint32 code_buffer;
char *zout;
char *zout_start;
char *zout_end;
int z_expandable;
zhuffman z_length, z_distance;
} zbuf;
stbi_inline static int zget8(zbuf *z)
{
if (z->zbuffer >= z->zbuffer_end) return 0;
return *z->zbuffer++;
}
static void fill_bits(zbuf *z)
{
do {
assert(z->code_buffer < (1U << z->num_bits));
z->code_buffer |= zget8(z) << z->num_bits;
z->num_bits += 8;
} while (z->num_bits <= 24);
}
stbi_inline static unsigned int zreceive(zbuf *z, int n)
{
unsigned int k;
if (z->num_bits < n) fill_bits(z);
k = z->code_buffer & ((1 << n) - 1);
z->code_buffer >>= n;
z->num_bits -= n;
return k;
}
stbi_inline static int zhuffman_decode(zbuf *a, zhuffman *z)
{
int b,s,k;
if (a->num_bits < 16) fill_bits(a);
b = z->fast[a->code_buffer & ZFAST_MASK];
if (b < 0xffff) {
s = z->size[b];
a->code_buffer >>= s;
a->num_bits -= s;
return z->value[b];
}
// not resolved by fast table, so compute it the slow way
// use jpeg approach, which requires MSbits at top
k = bit_reverse(a->code_buffer, 16);
for (s=ZFAST_BITS+1; ; ++s)
if (k < z->maxcode[s])
break;
if (s == 16) return -1; // invalid code!
// code size is s, so:
b = (k >> (16-s)) - z->firstcode[s] + z->firstsymbol[s];
assert(z->size[b] == s);
a->code_buffer >>= s;
a->num_bits -= s;
return z->value[b];
}
static int expand(zbuf *z, int n) // need to make room for n bytes
{
char *q;
int cur, limit;
if (!z->z_expandable) return e("output buffer limit","Corrupt PNG");
cur = (int) (z->zout - z->zout_start);
limit = (int) (z->zout_end - z->zout_start);
while (cur + n > limit)
limit *= 2;
q = (char *) realloc(z->zout_start, limit);
if (q == NULL) return e("outofmem", "Out of memory");
z->zout_start = q;
z->zout = q + cur;
z->zout_end = q + limit;
return 1;
}
static int length_base[31] = {
3,4,5,6,7,8,9,10,11,13,
15,17,19,23,27,31,35,43,51,59,
67,83,99,115,131,163,195,227,258,0,0 };
static int length_extra[31]=
{ 0,0,0,0,0,0,0,0,1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5,0,0,0 };
static int dist_base[32] = { 1,2,3,4,5,7,9,13,17,25,33,49,65,97,129,193,
257,385,513,769,1025,1537,2049,3073,4097,6145,8193,12289,16385,24577,0,0};
static int dist_extra[32] =
{ 0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13};
static int parse_huffman_block(zbuf *a)
{
for(;;) {
int z = zhuffman_decode(a, &a->z_length);
if (z < 256) {
if (z < 0) return e("bad huffman code","Corrupt PNG"); // error in huffman codes
if (a->zout >= a->zout_end) if (!expand(a, 1)) return 0;
*a->zout++ = (char) z;
} else {
stbi__uint8 *p;
int len,dist;
if (z == 256) return 1;
z -= 257;
len = length_base[z];
if (length_extra[z]) len += zreceive(a, length_extra[z]);
z = zhuffman_decode(a, &a->z_distance);
if (z < 0) return e("bad huffman code","Corrupt PNG");
dist = dist_base[z];
if (dist_extra[z]) dist += zreceive(a, dist_extra[z]);
if (a->zout - a->zout_start < dist) return e("bad dist","Corrupt PNG");
if (a->zout + len > a->zout_end) if (!expand(a, len)) return 0;
p = (stbi__uint8 *) (a->zout - dist);
while (len--)
*a->zout++ = *p++;
}
}
}
static int compute_huffman_codes(zbuf *a)
{
static stbi__uint8 length_dezigzag[19] = { 16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15 };
zhuffman z_codelength;
stbi__uint8 lencodes[286+32+137];//padding for maximum single op
stbi__uint8 codelength_sizes[19];
int i,n;
int hlit = zreceive(a,5) + 257;
int hdist = zreceive(a,5) + 1;
int hclen = zreceive(a,4) + 4;
memset(codelength_sizes, 0, sizeof(codelength_sizes));
for (i=0; i < hclen; ++i) {
int s = zreceive(a,3);
codelength_sizes[length_dezigzag[i]] = (stbi__uint8) s;
}
if (!zbuild_huffman(&z_codelength, codelength_sizes, 19)) return 0;
n = 0;
while (n < hlit + hdist) {
int c = zhuffman_decode(a, &z_codelength);
assert(c >= 0 && c < 19);
if (c < 16)
lencodes[n++] = (stbi__uint8) c;
else if (c == 16) {
c = zreceive(a,2)+3;
memset(lencodes+n, lencodes[n-1], c);
n += c;
} else if (c == 17) {
c = zreceive(a,3)+3;
memset(lencodes+n, 0, c);
n += c;
} else {
assert(c == 18);
c = zreceive(a,7)+11;
memset(lencodes+n, 0, c);
n += c;
}
}
if (n != hlit+hdist) return e("bad codelengths","Corrupt PNG");
if (!zbuild_huffman(&a->z_length, lencodes, hlit)) return 0;
if (!zbuild_huffman(&a->z_distance, lencodes+hlit, hdist)) return 0;
return 1;
}
static int parse_uncompressed_block(zbuf *a)
{
stbi__uint8 header[4];
int len,nlen,k;
if (a->num_bits & 7)
zreceive(a, a->num_bits & 7); // discard
// drain the bit-packed data into header
k = 0;
while (a->num_bits > 0) {
header[k++] = (stbi__uint8) (a->code_buffer & 255); // wtf this warns?
a->code_buffer >>= 8;
a->num_bits -= 8;
}
assert(a->num_bits == 0);
// now fill header the normal way
while (k < 4)
header[k++] = (stbi__uint8) zget8(a);
len = header[1] * 256 + header[0];
nlen = header[3] * 256 + header[2];
if (nlen != (len ^ 0xffff)) return e("zlib corrupt","Corrupt PNG");
if (a->zbuffer + len > a->zbuffer_end) return e("read past buffer","Corrupt PNG");
if (a->zout + len > a->zout_end)
if (!expand(a, len)) return 0;
memcpy(a->zout, a->zbuffer, len);
a->zbuffer += len;
a->zout += len;
return 1;
}
static int parse_zlib_header(zbuf *a)
{
int cmf = zget8(a);
int cm = cmf & 15;
/* int cinfo = cmf >> 4; */
int flg = zget8(a);
if ((cmf*256+flg) % 31 != 0) return e("bad zlib header","Corrupt PNG"); // zlib spec
if (flg & 32) return e("no preset dict","Corrupt PNG"); // preset dictionary not allowed in png
if (cm != 8) return e("bad compression","Corrupt PNG"); // DEFLATE required for png
// window = 1 << (8 + cinfo)... but who cares, we fully buffer output
return 1;
}
// @TODO: should statically initialize these for optimal thread safety
static stbi__uint8 default_length[288], default_distance[32];
static void init_defaults(void)
{
int i; // use <= to match clearly with spec
for (i=0; i <= 143; ++i) default_length[i] = 8;
for ( ; i <= 255; ++i) default_length[i] = 9;
for ( ; i <= 279; ++i) default_length[i] = 7;
for ( ; i <= 287; ++i) default_length[i] = 8;
for (i=0; i <= 31; ++i) default_distance[i] = 5;
}
int stbi_png_partial; // a quick hack to only allow decoding some of a PNG... I should implement real streaming support instead
static int parse_zlib(zbuf *a, int parse_header)
{
int final, type;
if (parse_header)
if (!parse_zlib_header(a)) return 0;
a->num_bits = 0;
a->code_buffer = 0;
do {
final = zreceive(a,1);
type = zreceive(a,2);
if (type == 0) {
if (!parse_uncompressed_block(a)) return 0;
} else if (type == 3) {
return 0;
} else {
if (type == 1) {
// use fixed code lengths
if (!default_distance[31]) init_defaults();
if (!zbuild_huffman(&a->z_length , default_length , 288)) return 0;
if (!zbuild_huffman(&a->z_distance, default_distance, 32)) return 0;
} else {
if (!compute_huffman_codes(a)) return 0;
}
if (!parse_huffman_block(a)) return 0;
}
if (stbi_png_partial && a->zout - a->zout_start > 65536)
break;
} while (!final);
return 1;
}
static int do_zlib(zbuf *a, char *obuf, int olen, int exp, int parse_header)
{
a->zout_start = obuf;
a->zout = obuf;
a->zout_end = obuf + olen;
a->z_expandable = exp;
return parse_zlib(a, parse_header);
}
char *stbi_zlib_decode_malloc_guesssize(const char *buffer, int len, int initial_size, int *outlen)
{
zbuf a;
char *p = (char *) malloc(initial_size);
if (p == NULL) return NULL;
a.zbuffer = (stbi__uint8 *) buffer;
a.zbuffer_end = (stbi__uint8 *) buffer + len;
if (do_zlib(&a, p, initial_size, 1, 1)) {
if (outlen) *outlen = (int) (a.zout - a.zout_start);
return a.zout_start;
} else {
free(a.zout_start);
return NULL;
}
}
char *stbi_zlib_decode_malloc(char const *buffer, int len, int *outlen)
{
return stbi_zlib_decode_malloc_guesssize(buffer, len, 16384, outlen);
}
char *stbi_zlib_decode_malloc_guesssize_headerflag(const char *buffer, int len, int initial_size, int *outlen, int parse_header)
{
zbuf a;
char *p = (char *) malloc(initial_size);
if (p == NULL) return NULL;
a.zbuffer = (stbi__uint8 *) buffer;
a.zbuffer_end = (stbi__uint8 *) buffer + len;
if (do_zlib(&a, p, initial_size, 1, parse_header)) {
if (outlen) *outlen = (int) (a.zout - a.zout_start);
return a.zout_start;
} else {
free(a.zout_start);
return NULL;
}
}
int stbi_zlib_decode_buffer(char *obuffer, int olen, char const *ibuffer, int ilen)
{
zbuf a;
a.zbuffer = (stbi__uint8 *) ibuffer;
a.zbuffer_end = (stbi__uint8 *) ibuffer + ilen;
if (do_zlib(&a, obuffer, olen, 0, 1))
return (int) (a.zout - a.zout_start);
else
return -1;
}
char *stbi_zlib_decode_noheader_malloc(char const *buffer, int len, int *outlen)
{
zbuf a;
char *p = (char *) malloc(16384);
if (p == NULL) return NULL;
a.zbuffer = (stbi__uint8 *) buffer;
a.zbuffer_end = (stbi__uint8 *) buffer+len;
if (do_zlib(&a, p, 16384, 1, 0)) {
if (outlen) *outlen = (int) (a.zout - a.zout_start);
return a.zout_start;
} else {
free(a.zout_start);
return NULL;
}
}
int stbi_zlib_decode_noheader_buffer(char *obuffer, int olen, const char *ibuffer, int ilen)
{
zbuf a;
a.zbuffer = (stbi__uint8 *) ibuffer;
a.zbuffer_end = (stbi__uint8 *) ibuffer + ilen;
if (do_zlib(&a, obuffer, olen, 0, 0))
return (int) (a.zout - a.zout_start);
else
return -1;
}
// public domain "baseline" PNG decoder v0.10 Sean Barrett 2006-11-18
// simple implementation
// - only 8-bit samples
// - no CRC checking
// - allocates lots of intermediate memory
// - avoids problem of streaming data between subsystems
// - avoids explicit window management
// performance
// - uses stb_zlib, a PD zlib implementation with fast huffman decoding
typedef struct
{
stbi__uint32 length;
stbi__uint32 type;
} chunk;
#define PNG_TYPE(a,b,c,d) (((a) << 24) + ((b) << 16) + ((c) << 8) + (d))
static chunk get_chunk_header(stbi *s)
{
chunk c;
c.length = get32(s);
c.type = get32(s);
return c;
}
static int check_png_header(stbi *s)
{
static stbi__uint8 png_sig[8] = { 137,80,78,71,13,10,26,10 };
int i;
for (i=0; i < 8; ++i)
if (get8u(s) != png_sig[i]) return e("bad png sig","Not a PNG");
return 1;
}
typedef struct
{
stbi *s;
stbi__uint8 *idata, *expanded, *out;
} png;
enum {
F_none=0, F_sub=1, F_up=2, F_avg=3, F_paeth=4,
F_avg_first, F_paeth_first
};
static stbi__uint8 first_row_filter[5] =
{
F_none, F_sub, F_none, F_avg_first, F_paeth_first
};
static int paeth(int a, int b, int c)
{
int p = a + b - c;
int pa = abs(p-a);
int pb = abs(p-b);
int pc = abs(p-c);
if (pa <= pb && pa <= pc) return a;
if (pb <= pc) return b;
return c;
}
// create the png data from post-deflated data
static int create_png_image_raw(png *a, stbi__uint8 *raw, stbi__uint32 raw_len, int out_n, stbi__uint32 x, stbi__uint32 y)
{
stbi *s = a->s;
stbi__uint32 i,j,stride = x*out_n;
int k;
int img_n = s->img_n; // copy it into a local for later
assert(out_n == s->img_n || out_n == s->img_n+1);
if (stbi_png_partial) y = 1;
a->out = (stbi__uint8 *) malloc(x * y * out_n);
if (!a->out) return e("outofmem", "Out of memory");
if (!stbi_png_partial) {
if (s->img_x == x && s->img_y == y) {
if (raw_len != (img_n * x + 1) * y) return e("not enough pixels","Corrupt PNG");
} else { // interlaced:
if (raw_len < (img_n * x + 1) * y) return e("not enough pixels","Corrupt PNG");
}
}
for (j=0; j < y; ++j) {
stbi__uint8 *cur = a->out + stride*j;
stbi__uint8 *prior = cur - stride;
int filter = *raw++;
if (filter > 4) return e("invalid filter","Corrupt PNG");
// if first row, use special filter that doesn't sample previous row
if (j == 0) filter = first_row_filter[filter];
// handle first pixel explicitly
for (k=0; k < img_n; ++k) {
switch (filter) {
case F_none : cur[k] = raw[k]; break;
case F_sub : cur[k] = raw[k]; break;
case F_up : cur[k] = raw[k] + prior[k]; break;
case F_avg : cur[k] = raw[k] + (prior[k]>>1); break;
case F_paeth : cur[k] = (stbi__uint8) (raw[k] + paeth(0,prior[k],0)); break;
case F_avg_first : cur[k] = raw[k]; break;
case F_paeth_first: cur[k] = raw[k]; break;
}
}
if (img_n != out_n) cur[img_n] = 255;
raw += img_n;
cur += out_n;
prior += out_n;
// this is a little gross, so that we don't switch per-pixel or per-component
if (img_n == out_n) {
#define CASE(f) \
case f: \
for (i=x-1; i >= 1; --i, raw+=img_n,cur+=img_n,prior+=img_n) \
for (k=0; k < img_n; ++k)
switch (filter) {
CASE(F_none) cur[k] = raw[k]; break;
CASE(F_sub) cur[k] = raw[k] + cur[k-img_n]; break;
CASE(F_up) cur[k] = raw[k] + prior[k]; break;
CASE(F_avg) cur[k] = raw[k] + ((prior[k] + cur[k-img_n])>>1); break;
CASE(F_paeth) cur[k] = (stbi__uint8) (raw[k] + paeth(cur[k-img_n],prior[k],prior[k-img_n])); break;
CASE(F_avg_first) cur[k] = raw[k] + (cur[k-img_n] >> 1); break;
CASE(F_paeth_first) cur[k] = (stbi__uint8) (raw[k] + paeth(cur[k-img_n],0,0)); break;
}
#undef CASE
} else {
assert(img_n+1 == out_n);
#define CASE(f) \
case f: \
for (i=x-1; i >= 1; --i, cur[img_n]=255,raw+=img_n,cur+=out_n,prior+=out_n) \
for (k=0; k < img_n; ++k)
switch (filter) {
CASE(F_none) cur[k] = raw[k]; break;
CASE(F_sub) cur[k] = raw[k] + cur[k-out_n]; break;
CASE(F_up) cur[k] = raw[k] + prior[k]; break;
CASE(F_avg) cur[k] = raw[k] + ((prior[k] + cur[k-out_n])>>1); break;
CASE(F_paeth) cur[k] = (stbi__uint8) (raw[k] + paeth(cur[k-out_n],prior[k],prior[k-out_n])); break;
CASE(F_avg_first) cur[k] = raw[k] + (cur[k-out_n] >> 1); break;
CASE(F_paeth_first) cur[k] = (stbi__uint8) (raw[k] + paeth(cur[k-out_n],0,0)); break;
}
#undef CASE
}
}
return 1;
}
static int create_png_image(png *a, stbi__uint8 *raw, stbi__uint32 raw_len, int out_n, int interlaced)
{
stbi__uint8 *final;
int p;
int save;
if (!interlaced)
return create_png_image_raw(a, raw, raw_len, out_n, a->s->img_x, a->s->img_y);
save = stbi_png_partial;
stbi_png_partial = 0;
// de-interlacing
final = (stbi__uint8 *) malloc(a->s->img_x * a->s->img_y * out_n);
for (p=0; p < 7; ++p) {
int xorig[] = { 0,4,0,2,0,1,0 };
int yorig[] = { 0,0,4,0,2,0,1 };
int xspc[] = { 8,8,4,4,2,2,1 };
int yspc[] = { 8,8,8,4,4,2,2 };
int i,j,x,y;
// pass1_x[4] = 0, pass1_x[5] = 1, pass1_x[12] = 1
x = (a->s->img_x - xorig[p] + xspc[p]-1) / xspc[p];
y = (a->s->img_y - yorig[p] + yspc[p]-1) / yspc[p];
if (x && y) {
if (!create_png_image_raw(a, raw, raw_len, out_n, x, y)) {
free(final);
return 0;
}
for (j=0; j < y; ++j)
for (i=0; i < x; ++i)
memcpy(final + (j*yspc[p]+yorig[p])*a->s->img_x*out_n + (i*xspc[p]+xorig[p])*out_n,
a->out + (j*x+i)*out_n, out_n);
free(a->out);
raw += (x*out_n+1)*y;
raw_len -= (x*out_n+1)*y;
}
}
a->out = final;
stbi_png_partial = save;
return 1;
}
static int compute_transparency(png *z, stbi__uint8 tc[3], int out_n)
{
stbi *s = z->s;
stbi__uint32 i, pixel_count = s->img_x * s->img_y;
stbi__uint8 *p = z->out;
// compute color-based transparency, assuming we've
// already got 255 as the alpha value in the output
assert(out_n == 2 || out_n == 4);
if (out_n == 2) {
for (i=0; i < pixel_count; ++i) {
p[1] = (p[0] == tc[0] ? 0 : 255);
p += 2;
}
} else {
for (i=0; i < pixel_count; ++i) {
if (p[0] == tc[0] && p[1] == tc[1] && p[2] == tc[2])
p[3] = 0;
p += 4;
}
}
return 1;
}
static int expand_palette(png *a, stbi__uint8 *palette, int len, int pal_img_n)
{
stbi__uint32 i, pixel_count = a->s->img_x * a->s->img_y;
stbi__uint8 *p, *temp_out, *orig = a->out;
p = (stbi__uint8 *) malloc(pixel_count * pal_img_n);
if (p == NULL) return e("outofmem", "Out of memory");
// between here and free(out) below, exitting would leak
temp_out = p;
if (pal_img_n == 3) {
for (i=0; i < pixel_count; ++i) {
int n = orig[i]*4;
p[0] = palette[n ];
p[1] = palette[n+1];
p[2] = palette[n+2];
p += 3;
}
} else {
for (i=0; i < pixel_count; ++i) {
int n = orig[i]*4;
p[0] = palette[n ];
p[1] = palette[n+1];
p[2] = palette[n+2];
p[3] = palette[n+3];
p += 4;
}
}
free(a->out);
a->out = temp_out;
STBI_NOTUSED(len);
return 1;
}
static int stbi_unpremultiply_on_load = 0;
static int stbi_de_iphone_flag = 0;
void stbi_set_unpremultiply_on_load(int flag_true_if_should_unpremultiply)
{
stbi_unpremultiply_on_load = flag_true_if_should_unpremultiply;
}
void stbi_convert_iphone_png_to_rgb(int flag_true_if_should_convert)
{
stbi_de_iphone_flag = flag_true_if_should_convert;
}
static void stbi_de_iphone(png *z)
{
stbi *s = z->s;
stbi__uint32 i, pixel_count = s->img_x * s->img_y;
stbi__uint8 *p = z->out;
if (s->img_out_n == 3) { // convert bgr to rgb
for (i=0; i < pixel_count; ++i) {
stbi__uint8 t = p[0];
p[0] = p[2];
p[2] = t;
p += 3;
}
} else {
assert(s->img_out_n == 4);
if (stbi_unpremultiply_on_load) {
// convert bgr to rgb and unpremultiply
for (i=0; i < pixel_count; ++i) {
stbi__uint8 a = p[3];
stbi__uint8 t = p[0];
if (a) {
p[0] = p[2] * 255 / a;
p[1] = p[1] * 255 / a;
p[2] = t * 255 / a;
} else {
p[0] = p[2];
p[2] = t;
}
p += 4;
}
} else {
// convert bgr to rgb
for (i=0; i < pixel_count; ++i) {
stbi__uint8 t = p[0];
p[0] = p[2];
p[2] = t;
p += 4;
}
}
}
}
static int parse_png_file(png *z, int scan, int req_comp)
{
stbi__uint8 palette[1024], pal_img_n=0;
stbi__uint8 has_trans=0, tc[3];
stbi__uint32 ioff=0, idata_limit=0, i, pal_len=0;
int first=1,k,interlace=0, iphone=0;
stbi *s = z->s;
z->expanded = NULL;
z->idata = NULL;
z->out = NULL;
if (!check_png_header(s)) return 0;
if (scan == SCAN_type) return 1;
for (;;) {
chunk c = get_chunk_header(s);
switch (c.type) {
case PNG_TYPE('C','g','B','I'):
iphone = stbi_de_iphone_flag;
skip(s, c.length);
break;
case PNG_TYPE('I','H','D','R'): {
int depth,color,comp,filter;
if (!first) return e("multiple IHDR","Corrupt PNG");
first = 0;
if (c.length != 13) return e("bad IHDR len","Corrupt PNG");
s->img_x = get32(s); if (s->img_x > (1 << 24)) return e("too large","Very large image (corrupt?)");
s->img_y = get32(s); if (s->img_y > (1 << 24)) return e("too large","Very large image (corrupt?)");
depth = get8(s); if (depth != 8) return e("8bit only","PNG not supported: 8-bit only");
color = get8(s); if (color > 6) return e("bad ctype","Corrupt PNG");
if (color == 3) pal_img_n = 3; else if (color & 1) return e("bad ctype","Corrupt PNG");
comp = get8(s); if (comp) return e("bad comp method","Corrupt PNG");
filter= get8(s); if (filter) return e("bad filter method","Corrupt PNG");
interlace = get8(s); if (interlace>1) return e("bad interlace method","Corrupt PNG");
if (!s->img_x || !s->img_y) return e("0-pixel image","Corrupt PNG");
if (!pal_img_n) {
s->img_n = (color & 2 ? 3 : 1) + (color & 4 ? 1 : 0);
if ((1 << 30) / s->img_x / s->img_n < s->img_y) return e("too large", "Image too large to decode");
if (scan == SCAN_header) return 1;
} else {
// if paletted, then pal_n is our final components, and
// img_n is # components to decompress/filter.
s->img_n = 1;
if ((1 << 30) / s->img_x / 4 < s->img_y) return e("too large","Corrupt PNG");
// if SCAN_header, have to scan to see if we have a tRNS
}
break;
}
case PNG_TYPE('P','L','T','E'): {
if (first) return e("first not IHDR", "Corrupt PNG");
if (c.length > 256*3) return e("invalid PLTE","Corrupt PNG");
pal_len = c.length / 3;
if (pal_len * 3 != c.length) return e("invalid PLTE","Corrupt PNG");
for (i=0; i < pal_len; ++i) {
palette[i*4+0] = get8u(s);
palette[i*4+1] = get8u(s);
palette[i*4+2] = get8u(s);
palette[i*4+3] = 255;
}
break;
}
case PNG_TYPE('t','R','N','S'): {
if (first) return e("first not IHDR", "Corrupt PNG");
if (z->idata) return e("tRNS after IDAT","Corrupt PNG");
if (pal_img_n) {
if (scan == SCAN_header) { s->img_n = 4; return 1; }
if (pal_len == 0) return e("tRNS before PLTE","Corrupt PNG");
if (c.length > pal_len) return e("bad tRNS len","Corrupt PNG");
pal_img_n = 4;
for (i=0; i < c.length; ++i)
palette[i*4+3] = get8u(s);
} else {
if (!(s->img_n & 1)) return e("tRNS with alpha","Corrupt PNG");
if (c.length != (stbi__uint32) s->img_n*2) return e("bad tRNS len","Corrupt PNG");
has_trans = 1;
for (k=0; k < s->img_n; ++k)
tc[k] = (stbi__uint8) get16(s); // non 8-bit images will be larger
}
break;
}
case PNG_TYPE('I','D','A','T'): {
if (first) return e("first not IHDR", "Corrupt PNG");
if (pal_img_n && !pal_len) return e("no PLTE","Corrupt PNG");
if (scan == SCAN_header) { s->img_n = pal_img_n; return 1; }
if (ioff + c.length > idata_limit) {
stbi__uint8 *p;
if (idata_limit == 0) idata_limit = c.length > 4096 ? c.length : 4096;
while (ioff + c.length > idata_limit)
idata_limit *= 2;
p = (stbi__uint8 *) realloc(z->idata, idata_limit); if (p == NULL) return e("outofmem", "Out of memory");
z->idata = p;
}
if (!getn(s, z->idata+ioff,c.length)) return e("outofdata","Corrupt PNG");
ioff += c.length;
break;
}
case PNG_TYPE('I','E','N','D'): {
stbi__uint32 raw_len;
if (first) return e("first not IHDR", "Corrupt PNG");
if (scan != SCAN_load) return 1;
if (z->idata == NULL) return e("no IDAT","Corrupt PNG");
z->expanded = (stbi__uint8 *) stbi_zlib_decode_malloc_guesssize_headerflag((char *) z->idata, ioff, 16384, (int *) &raw_len, !iphone);
if (z->expanded == NULL) return 0; // zlib should set error
free(z->idata); z->idata = NULL;
if ((req_comp == s->img_n+1 && req_comp != 3 && !pal_img_n) || has_trans)
s->img_out_n = s->img_n+1;
else
s->img_out_n = s->img_n;
if (!create_png_image(z, z->expanded, raw_len, s->img_out_n, interlace)) return 0;
if (has_trans)
if (!compute_transparency(z, tc, s->img_out_n)) return 0;
if (iphone && s->img_out_n > 2)
stbi_de_iphone(z);
if (pal_img_n) {
// pal_img_n == 3 or 4
s->img_n = pal_img_n; // record the actual colors we had
s->img_out_n = pal_img_n;
if (req_comp >= 3) s->img_out_n = req_comp;
if (!expand_palette(z, palette, pal_len, s->img_out_n))
return 0;
}
free(z->expanded); z->expanded = NULL;
return 1;
}
default:
// if critical, fail
if (first) return e("first not IHDR", "Corrupt PNG");
if ((c.type & (1 << 29)) == 0) {
#ifndef STBI_NO_FAILURE_STRINGS
// not threadsafe
static char invalid_chunk[] = "XXXX chunk not known";
invalid_chunk[0] = (stbi__uint8) (c.type >> 24);
invalid_chunk[1] = (stbi__uint8) (c.type >> 16);
invalid_chunk[2] = (stbi__uint8) (c.type >> 8);
invalid_chunk[3] = (stbi__uint8) (c.type >> 0);
#endif
return e(invalid_chunk, "PNG not supported: unknown chunk type");
}
skip(s, c.length);
break;
}
// end of chunk, read and skip CRC
get32(s);
}
}
static unsigned char *do_png(png *p, int *x, int *y, int *n, int req_comp)
{
unsigned char *result=NULL;
if (req_comp < 0 || req_comp > 4) return epuc("bad req_comp", "Internal error");
if (parse_png_file(p, SCAN_load, req_comp)) {
result = p->out;
p->out = NULL;
if (req_comp && req_comp != p->s->img_out_n) {
result = convert_format(result, p->s->img_out_n, req_comp, p->s->img_x, p->s->img_y);
p->s->img_out_n = req_comp;
if (result == NULL) return result;
}
*x = p->s->img_x;
*y = p->s->img_y;
if (n) *n = p->s->img_n;
}
free(p->out); p->out = NULL;
free(p->expanded); p->expanded = NULL;
free(p->idata); p->idata = NULL;
return result;
}
static unsigned char *stbi_png_load(stbi *s, int *x, int *y, int *comp, int req_comp)
{
png p;
p.s = s;
return do_png(&p, x,y,comp,req_comp);
}
static int stbi_png_test(stbi *s)
{
int r;
r = check_png_header(s);
stbi_rewind(s);
return r;
}
static int stbi_png_info_raw(png *p, int *x, int *y, int *comp)
{
if (!parse_png_file(p, SCAN_header, 0)) {
stbi_rewind( p->s );
return 0;
}
if (x) *x = p->s->img_x;
if (y) *y = p->s->img_y;
if (comp) *comp = p->s->img_n;
return 1;
}
static int stbi_png_info(stbi *s, int *x, int *y, int *comp)
{
png p;
p.s = s;
return stbi_png_info_raw(&p, x, y, comp);
}
// Microsoft/Windows BMP image
static int bmp_test(stbi *s)
{
int sz;
if (get8(s) != 'B') return 0;
if (get8(s) != 'M') return 0;
get32le(s); // discard filesize
get16le(s); // discard reserved
get16le(s); // discard reserved
get32le(s); // discard data offset
sz = get32le(s);
if (sz == 12 || sz == 40 || sz == 56 || sz == 108) return 1;
return 0;
}
static int stbi_bmp_test(stbi *s)
{
int r = bmp_test(s);
stbi_rewind(s);
return r;
}
// returns 0..31 for the highest set bit
static int high_bit(unsigned int z)
{
int n=0;
if (z == 0) return -1;
if (z >= 0x10000) n += 16, z >>= 16;
if (z >= 0x00100) n += 8, z >>= 8;
if (z >= 0x00010) n += 4, z >>= 4;
if (z >= 0x00004) n += 2, z >>= 2;
if (z >= 0x00002) n += 1, z >>= 1;
return n;
}
static int bitcount(unsigned int a)
{
a = (a & 0x55555555) + ((a >> 1) & 0x55555555); // max 2
a = (a & 0x33333333) + ((a >> 2) & 0x33333333); // max 4
a = (a + (a >> 4)) & 0x0f0f0f0f; // max 8 per 4, now 8 bits
a = (a + (a >> 8)); // max 16 per 8 bits
a = (a + (a >> 16)); // max 32 per 8 bits
return a & 0xff;
}
static int shiftsigned(int v, int shift, int bits)
{
int result;
int z=0;
if (shift < 0) v <<= -shift;
else v >>= shift;
result = v;
z = bits;
while (z < 8) {
result += v >> z;
z += bits;
}
return result;
}
static stbi_uc *bmp_load(stbi *s, int *x, int *y, int *comp, int req_comp)
{
stbi__uint8 *out;
unsigned int mr=0,mg=0,mb=0,ma=0, fake_a=0;
stbi_uc pal[256][4];
int psize=0,i,j,compress=0,width;
int bpp, flip_vertically, pad, target, offset, hsz;
if (get8(s) != 'B' || get8(s) != 'M') return epuc("not BMP", "Corrupt BMP");
get32le(s); // discard filesize
get16le(s); // discard reserved
get16le(s); // discard reserved
offset = get32le(s);
hsz = get32le(s);
if (hsz != 12 && hsz != 40 && hsz != 56 && hsz != 108) return epuc("unknown BMP", "BMP type not supported: unknown");
if (hsz == 12) {
s->img_x = get16le(s);
s->img_y = get16le(s);
} else {
s->img_x = get32le(s);
s->img_y = get32le(s);
}
if (get16le(s) != 1) return epuc("bad BMP", "bad BMP");
bpp = get16le(s);
if (bpp == 1) return epuc("monochrome", "BMP type not supported: 1-bit");
flip_vertically = ((int) s->img_y) > 0;
s->img_y = abs((int) s->img_y);
if (hsz == 12) {
if (bpp < 24)
psize = (offset - 14 - 24) / 3;
} else {
compress = get32le(s);
if (compress == 1 || compress == 2) return epuc("BMP RLE", "BMP type not supported: RLE");
get32le(s); // discard sizeof
get32le(s); // discard hres
get32le(s); // discard vres
get32le(s); // discard colorsused
get32le(s); // discard max important
if (hsz == 40 || hsz == 56) {
if (hsz == 56) {
get32le(s);
get32le(s);
get32le(s);
get32le(s);
}
if (bpp == 16 || bpp == 32) {
mr = mg = mb = 0;
if (compress == 0) {
if (bpp == 32) {
mr = 0xffu << 16;
mg = 0xffu << 8;
mb = 0xffu << 0;
ma = 0xffu << 24;
fake_a = 1; // @TODO: check for cases like alpha value is all 0 and switch it to 255
STBI_UNUSED(fake_a);
} else {
mr = 31u << 10;
mg = 31u << 5;
mb = 31u << 0;
}
} else if (compress == 3) {
mr = get32le(s);
mg = get32le(s);
mb = get32le(s);
// not documented, but generated by photoshop and handled by mspaint
if (mr == mg && mg == mb) {
// ?!?!?
return epuc("bad BMP", "bad BMP");
}
} else
return epuc("bad BMP", "bad BMP");
}
} else {
assert(hsz == 108);
mr = get32le(s);
mg = get32le(s);
mb = get32le(s);
ma = get32le(s);
get32le(s); // discard color space
for (i=0; i < 12; ++i)
get32le(s); // discard color space parameters
}
if (bpp < 16)
psize = (offset - 14 - hsz) >> 2;
}
s->img_n = ma ? 4 : 3;
if (req_comp && req_comp >= 3) // we can directly decode 3 or 4
target = req_comp;
else
target = s->img_n; // if they want monochrome, we'll post-convert
out = (stbi_uc *) malloc(target * s->img_x * s->img_y);
if (!out) return epuc("outofmem", "Out of memory");
if (bpp < 16) {
int z=0;
if (psize == 0 || psize > 256) { free(out); return epuc("invalid", "Corrupt BMP"); }
for (i=0; i < psize; ++i) {
pal[i][2] = get8u(s);
pal[i][1] = get8u(s);
pal[i][0] = get8u(s);
if (hsz != 12) get8(s);
pal[i][3] = 255;
}
skip(s, offset - 14 - hsz - psize * (hsz == 12 ? 3 : 4));
if (bpp == 4) width = (s->img_x + 1) >> 1;
else if (bpp == 8) width = s->img_x;
else { free(out); return epuc("bad bpp", "Corrupt BMP"); }
pad = (-width)&3;
for (j=0; j < (int) s->img_y; ++j) {
for (i=0; i < (int) s->img_x; i += 2) {
int v=get8(s),v2=0;
if (bpp == 4) {
v2 = v & 15;
v >>= 4;
}
out[z++] = pal[v][0];
out[z++] = pal[v][1];
out[z++] = pal[v][2];
if (target == 4) out[z++] = 255;
if (i+1 == (int) s->img_x) break;
v = (bpp == 8) ? get8(s) : v2;
out[z++] = pal[v][0];
out[z++] = pal[v][1];
out[z++] = pal[v][2];
if (target == 4) out[z++] = 255;
}
skip(s, pad);
}
} else {
int rshift=0,gshift=0,bshift=0,ashift=0,rcount=0,gcount=0,bcount=0,acount=0;
int z = 0;
int easy=0;
skip(s, offset - 14 - hsz);
if (bpp == 24) width = 3 * s->img_x;
else if (bpp == 16) width = 2*s->img_x;
else /* bpp = 32 and pad = 0 */ width=0;
pad = (-width) & 3;
if (bpp == 24) {
easy = 1;
} else if (bpp == 32) {
if (mb == 0xff && mg == 0xff00 && mr == 0x00ff0000 && ma == 0xff000000)
easy = 2;
}
if (!easy) {
if (!mr || !mg || !mb) { free(out); return epuc("bad masks", "Corrupt BMP"); }
// right shift amt to put high bit in position #7
rshift = high_bit(mr)-7; rcount = bitcount(mr);
gshift = high_bit(mg)-7; gcount = bitcount(mg);
bshift = high_bit(mb)-7; bcount = bitcount(mb);
ashift = high_bit(ma)-7; acount = bitcount(ma);
}
for (j=0; j < (int) s->img_y; ++j) {
if (easy) {
for (i=0; i < (int) s->img_x; ++i) {
int a;
out[z+2] = get8u(s);
out[z+1] = get8u(s);
out[z+0] = get8u(s);
z += 3;
a = (easy == 2 ? get8(s) : 255);
if (target == 4) out[z++] = (stbi__uint8) a;
}
} else {
for (i=0; i < (int) s->img_x; ++i) {
stbi__uint32 v = (stbi_uint32) (bpp == 16 ? get16le(s) : get32le(s));
int a;
out[z++] = (stbi__uint8) shiftsigned(v & mr, rshift, rcount);
out[z++] = (stbi__uint8) shiftsigned(v & mg, gshift, gcount);
out[z++] = (stbi__uint8) shiftsigned(v & mb, bshift, bcount);
a = (ma ? shiftsigned(v & ma, ashift, acount) : 255);
if (target == 4) out[z++] = (stbi__uint8) a;
}
}
skip(s, pad);
}
}
if (flip_vertically) {
stbi_uc t;
for (j=0; j < (int) s->img_y>>1; ++j) {
stbi_uc *p1 = out + j *s->img_x*target;
stbi_uc *p2 = out + (s->img_y-1-j)*s->img_x*target;
for (i=0; i < (int) s->img_x*target; ++i) {
t = p1[i], p1[i] = p2[i], p2[i] = t;
}
}
}
if (req_comp && req_comp != target) {
out = convert_format(out, target, req_comp, s->img_x, s->img_y);
if (out == NULL) return out; // convert_format frees input on failure
}
*x = s->img_x;
*y = s->img_y;
if (comp) *comp = s->img_n;
return out;
}
static stbi_uc *stbi_bmp_load(stbi *s,int *x, int *y, int *comp, int req_comp)
{
return bmp_load(s, x,y,comp,req_comp);
}
// Targa Truevision - TGA
// by Jonathan Dummer
static int tga_info(stbi *s, int *x, int *y, int *comp)
{
int tga_w, tga_h, tga_comp;
int sz;
get8u(s); // discard Offset
sz = get8u(s); // color type
if( sz > 1 ) {
stbi_rewind(s);
return 0; // only RGB or indexed allowed
}
sz = get8u(s); // image type
// only RGB or grey allowed, +/- RLE
if ((sz != 1) && (sz != 2) && (sz != 3) && (sz != 9) && (sz != 10) && (sz != 11)) return 0;
skip(s,9);
tga_w = get16le(s);
if( tga_w < 1 ) {
stbi_rewind(s);
return 0; // test width
}
tga_h = get16le(s);
if( tga_h < 1 ) {
stbi_rewind(s);
return 0; // test height
}
sz = get8(s); // bits per pixel
// only RGB or RGBA or grey allowed
if ((sz != 8) && (sz != 16) && (sz != 24) && (sz != 32)) {
stbi_rewind(s);
return 0;
}
tga_comp = sz;
if (x) *x = tga_w;
if (y) *y = tga_h;
if (comp) *comp = tga_comp / 8;
return 1; // seems to have passed everything
}
int stbi_tga_info(stbi *s, int *x, int *y, int *comp)
{
return tga_info(s, x, y, comp);
}
static int tga_test(stbi *s)
{
int sz;
get8u(s); // discard Offset
sz = get8u(s); // color type
if ( sz > 1 ) return 0; // only RGB or indexed allowed
sz = get8u(s); // image type
if ( (sz != 1) && (sz != 2) && (sz != 3) && (sz != 9) && (sz != 10) && (sz != 11) ) return 0; // only RGB or grey allowed, +/- RLE
get16(s); // discard palette start
get16(s); // discard palette length
get8(s); // discard bits per palette color entry
get16(s); // discard x origin
get16(s); // discard y origin
if ( get16(s) < 1 ) return 0; // test width
if ( get16(s) < 1 ) return 0; // test height
sz = get8(s); // bits per pixel
if ( (sz != 8) && (sz != 16) && (sz != 24) && (sz != 32) ) return 0; // only RGB or RGBA or grey allowed
return 1; // seems to have passed everything
}
static int stbi_tga_test(stbi *s)
{
int res = tga_test(s);
stbi_rewind(s);
return res;
}
static stbi_uc *tga_load(stbi *s, int *x, int *y, int *comp, int req_comp)
{
// read in the TGA header stuff
int tga_offset = get8u(s);
int tga_indexed = get8u(s);
int tga_image_type = get8u(s);
int tga_is_RLE = 0;
int tga_palette_start = get16le(s);
int tga_palette_len = get16le(s);
int tga_palette_bits = get8u(s);
int tga_x_origin = get16le(s);
int tga_y_origin = get16le(s);
int tga_width = get16le(s);
int tga_height = get16le(s);
int tga_bits_per_pixel = get8u(s);
int tga_inverted = get8u(s);
// image data
unsigned char *tga_data;
unsigned char *tga_palette = NULL;
int i, j;
unsigned char raw_data[4];
unsigned char trans_data[4];
int RLE_count = 0;
int RLE_repeating = 0;
int read_next_pixel = 1;
// do a tiny bit of precessing
if ( tga_image_type >= 8 )
{
tga_image_type -= 8;
tga_is_RLE = 1;
}
/* int tga_alpha_bits = tga_inverted & 15; */
tga_inverted = 1 - ((tga_inverted >> 5) & 1);
// error check
if ( //(tga_indexed) ||
(tga_width < 1) || (tga_height < 1) ||
(tga_image_type < 1) || (tga_image_type > 3) ||
((tga_bits_per_pixel != 8) && (tga_bits_per_pixel != 16) &&
(tga_bits_per_pixel != 24) && (tga_bits_per_pixel != 32))
)
{
return NULL; // we don't report this as a bad TGA because we don't even know if it's TGA
}
// If I'm paletted, then I'll use the number of bits from the palette
if ( tga_indexed )
{
tga_bits_per_pixel = tga_palette_bits;
}
// tga info
*x = tga_width;
*y = tga_height;
if ( (req_comp < 1) || (req_comp > 4) )
{
// just use whatever the file was
req_comp = tga_bits_per_pixel / 8;
*comp = req_comp;
} else
{
// force a new number of components
*comp = tga_bits_per_pixel/8;
}
tga_data = (unsigned char*)malloc( tga_width * tga_height * req_comp );
if (!tga_data) return epuc("outofmem", "Out of memory");
// skip to the data's starting position (offset usually = 0)
skip(s, tga_offset );
// do I need to load a palette?
if ( tga_indexed )
{
// any data to skip? (offset usually = 0)
skip(s, tga_palette_start );
// load the palette
tga_palette = (unsigned char*)malloc( tga_palette_len * tga_palette_bits / 8 );
if (!tga_palette) {
free(tga_data);
return epuc("outofmem", "Out of memory");
}
if (!getn(s, tga_palette, tga_palette_len * tga_palette_bits / 8 )) {
free(tga_data);
free(tga_palette);
return epuc("bad palette", "Corrupt TGA");
}
}
// load the data
trans_data[0] = trans_data[1] = trans_data[2] = trans_data[3] = 0;
for (i=0; i < tga_width * tga_height; ++i)
{
// if I'm in RLE mode, do I need to get a RLE chunk?
if ( tga_is_RLE )
{
if ( RLE_count == 0 )
{
// yep, get the next byte as a RLE command
int RLE_cmd = get8u(s);
RLE_count = 1 + (RLE_cmd & 127);
RLE_repeating = RLE_cmd >> 7;
read_next_pixel = 1;
} else if ( !RLE_repeating )
{
read_next_pixel = 1;
}
} else
{
read_next_pixel = 1;
}
// OK, if I need to read a pixel, do it now
if ( read_next_pixel )
{
// load however much data we did have
if ( tga_indexed )
{
// read in 1 byte, then perform the lookup
int pal_idx = get8u(s);
if ( pal_idx >= tga_palette_len )
{
// invalid index
pal_idx = 0;
}
pal_idx *= tga_bits_per_pixel / 8;
for (j = 0; j*8 < tga_bits_per_pixel; ++j)
{
raw_data[j] = tga_palette[pal_idx+j];
}
} else
{
// read in the data raw
for (j = 0; j*8 < tga_bits_per_pixel; ++j)
{
raw_data[j] = get8u(s);
}
}
// convert raw to the intermediate format
switch (tga_bits_per_pixel)
{
case 8:
// Luminous => RGBA
trans_data[0] = raw_data[0];
trans_data[1] = raw_data[0];
trans_data[2] = raw_data[0];
trans_data[3] = 255;
break;
case 16:
// Luminous,Alpha => RGBA
trans_data[0] = raw_data[0];
trans_data[1] = raw_data[0];
trans_data[2] = raw_data[0];
trans_data[3] = raw_data[1];
break;
case 24:
// BGR => RGBA
trans_data[0] = raw_data[2];
trans_data[1] = raw_data[1];
trans_data[2] = raw_data[0];
trans_data[3] = 255;
break;
case 32:
// BGRA => RGBA
trans_data[0] = raw_data[2];
trans_data[1] = raw_data[1];
trans_data[2] = raw_data[0];
trans_data[3] = raw_data[3];
break;
}
// clear the reading flag for the next pixel
read_next_pixel = 0;
} // end of reading a pixel
// convert to final format
switch (req_comp)
{
case 1:
// RGBA => Luminance
tga_data[i*req_comp+0] = compute_y(trans_data[0],trans_data[1],trans_data[2]);
break;
case 2:
// RGBA => Luminance,Alpha
tga_data[i*req_comp+0] = compute_y(trans_data[0],trans_data[1],trans_data[2]);
tga_data[i*req_comp+1] = trans_data[3];
break;
case 3:
// RGBA => RGB
tga_data[i*req_comp+0] = trans_data[0];
tga_data[i*req_comp+1] = trans_data[1];
tga_data[i*req_comp+2] = trans_data[2];
break;
case 4:
// RGBA => RGBA
tga_data[i*req_comp+0] = trans_data[0];
tga_data[i*req_comp+1] = trans_data[1];
tga_data[i*req_comp+2] = trans_data[2];
tga_data[i*req_comp+3] = trans_data[3];
break;
}
// in case we're in RLE mode, keep counting down
--RLE_count;
}
// do I need to invert the image?
if ( tga_inverted )
{
for (j = 0; j*2 < tga_height; ++j)
{
int index1 = j * tga_width * req_comp;
int index2 = (tga_height - 1 - j) * tga_width * req_comp;
for (i = tga_width * req_comp; i > 0; --i)
{
unsigned char temp = tga_data[index1];
tga_data[index1] = tga_data[index2];
tga_data[index2] = temp;
++index1;
++index2;
}
}
}
// clear my palette, if I had one
if ( tga_palette != NULL )
{
free( tga_palette );
}
// the things I do to get rid of an error message, and yet keep
// Microsoft's C compilers happy... [8^(
tga_palette_start = tga_palette_len = tga_palette_bits =
tga_x_origin = tga_y_origin = 0;
// OK, done
return tga_data;
}
static stbi_uc *stbi_tga_load(stbi *s, int *x, int *y, int *comp, int req_comp)
{
return tga_load(s,x,y,comp,req_comp);
}
// *************************************************************************************************
// Photoshop PSD loader -- PD by Thatcher Ulrich, integration by Nicolas Schulz, tweaked by STB
static int psd_test(stbi *s)
{
if (get32(s) != 0x38425053) return 0; // "8BPS"
else return 1;
}
static int stbi_psd_test(stbi *s)
{
int r = psd_test(s);
stbi_rewind(s);
return r;
}
static stbi_uc *psd_load(stbi *s, int *x, int *y, int *comp, int req_comp)
{
int pixelCount;
int channelCount, compression;
int channel, i, count, len;
int w,h;
stbi__uint8 *out;
// Check identifier
if (get32(s) != 0x38425053) // "8BPS"
return epuc("not PSD", "Corrupt PSD image");
// Check file type version.
if (get16(s) != 1)
return epuc("wrong version", "Unsupported version of PSD image");
// Skip 6 reserved bytes.
skip(s, 6 );
// Read the number of channels (R, G, B, A, etc).
channelCount = get16(s);
if (channelCount < 0 || channelCount > 16)
return epuc("wrong channel count", "Unsupported number of channels in PSD image");
// Read the rows and columns of the image.
h = get32(s);
w = get32(s);
// Make sure the depth is 8 bits.
if (get16(s) != 8)
return epuc("unsupported bit depth", "PSD bit depth is not 8 bit");
// Make sure the color mode is RGB.
// Valid options are:
// 0: Bitmap
// 1: Grayscale
// 2: Indexed color
// 3: RGB color
// 4: CMYK color
// 7: Multichannel
// 8: Duotone
// 9: Lab color
if (get16(s) != 3)
return epuc("wrong color format", "PSD is not in RGB color format");
// Skip the Mode Data. (It's the palette for indexed color; other info for other modes.)
skip(s,get32(s) );
// Skip the image resources. (resolution, pen tool paths, etc)
skip(s, get32(s) );
// Skip the reserved data.
skip(s, get32(s) );
// Find out if the data is compressed.
// Known values:
// 0: no compression
// 1: RLE compressed
compression = get16(s);
if (compression > 1)
return epuc("bad compression", "PSD has an unknown compression format");
// Create the destination image.
out = (stbi_uc *) malloc(4 * w*h);
if (!out) return epuc("outofmem", "Out of memory");
pixelCount = w*h;
// Initialize the data to zero.
//memset( out, 0, pixelCount * 4 );
// Finally, the image data.
if (compression) {
// RLE as used by .PSD and .TIFF
// Loop until you get the number of unpacked bytes you are expecting:
// Read the next source byte into n.
// If n is between 0 and 127 inclusive, copy the next n+1 bytes literally.
// Else if n is between -127 and -1 inclusive, copy the next byte -n+1 times.
// Else if n is 128, noop.
// Endloop
// The RLE-compressed data is preceeded by a 2-byte data count for each row in the data,
// which we're going to just skip.
skip(s, h * channelCount * 2 );
// Read the RLE data by channel.
for (channel = 0; channel < 4; channel++) {
stbi__uint8 *p;
p = out+channel;
if (channel >= channelCount) {
// Fill this channel with default data.
for (i = 0; i < pixelCount; i++) *p = (channel == 3 ? 255 : 0), p += 4;
} else {
// Read the RLE data.
count = 0;
while (count < pixelCount) {
len = get8(s);
if (len == 128) {
// No-op.
} else if (len < 128) {
// Copy next len+1 bytes literally.
len++;
count += len;
while (len) {
*p = get8u(s);
p += 4;
len--;
}
} else if (len > 128) {
stbi__uint8 val;
// Next -len+1 bytes in the dest are replicated from next source byte.
// (Interpret len as a negative 8-bit int.)
len ^= 0x0FF;
len += 2;
val = get8u(s);
count += len;
while (len) {
*p = val;
p += 4;
len--;
}
}
}
}
}
} else {
// We're at the raw image data. It's each channel in order (Red, Green, Blue, Alpha, ...)
// where each channel consists of an 8-bit value for each pixel in the image.
// Read the data by channel.
for (channel = 0; channel < 4; channel++) {
stbi__uint8 *p;
p = out + channel;
if (channel > channelCount) {
// Fill this channel with default data.
for (i = 0; i < pixelCount; i++) *p = channel == 3 ? 255 : 0, p += 4;
} else {
// Read the data.
for (i = 0; i < pixelCount; i++)
*p = get8u(s), p += 4;
}
}
}
if (req_comp && req_comp != 4) {
out = convert_format(out, 4, req_comp, w, h);
if (out == NULL) return out; // convert_format frees input on failure
}
if (comp) *comp = channelCount;
*y = h;
*x = w;
return out;
}
static stbi_uc *stbi_psd_load(stbi *s, int *x, int *y, int *comp, int req_comp)
{
return psd_load(s,x,y,comp,req_comp);
}
// *************************************************************************************************
// Softimage PIC loader
// by Tom Seddon
//
// See http://softimage.wiki.softimage.com/index.php/INFO:_PIC_file_format
// See http://ozviz.wasp.uwa.edu.au/~pbourke/dataformats/softimagepic/
static int pic_is4(stbi *s,const char *str)
{
int i;
for (i=0; i<4; ++i)
if (get8(s) != (stbi_uc)str[i])
return 0;
return 1;
}
static int pic_test(stbi *s)
{
int i;
if (!pic_is4(s,"\x53\x80\xF6\x34"))
return 0;
for(i=0;i<84;++i)
get8(s);
if (!pic_is4(s,"PICT"))
return 0;
return 1;
}
typedef struct
{
stbi_uc size,type,channel;
} pic_packet_t;
static stbi_uc *pic_readval(stbi *s, int channel, stbi_uc *dest)
{
int mask=0x80, i;
for (i=0; i<4; ++i, mask>>=1) {
if (channel & mask) {
if (at_eof(s)) return epuc("bad file","PIC file too short");
dest[i]=get8u(s);
}
}
return dest;
}
static void pic_copyval(int channel,stbi_uc *dest,const stbi_uc *src)
{
int mask=0x80,i;
for (i=0;i<4; ++i, mask>>=1)
if (channel&mask)
dest[i]=src[i];
}
static stbi_uc *pic_load2(stbi *s,int width,int height,int *comp, stbi_uc *result)
{
int act_comp=0,num_packets=0,y,chained;
pic_packet_t packets[10];
// this will (should...) cater for even some bizarre stuff like having data
// for the same channel in multiple packets.
do {
pic_packet_t *packet;
if (num_packets==sizeof(packets)/sizeof(packets[0]))
return epuc("bad format","too many packets");
packet = &packets[num_packets++];
chained = get8(s);
packet->size = get8u(s);
packet->type = get8u(s);
packet->channel = get8u(s);
act_comp |= packet->channel;
if (at_eof(s)) return epuc("bad file","file too short (reading packets)");
if (packet->size != 8) return epuc("bad format","packet isn't 8bpp");
} while (chained);
*comp = (act_comp & 0x10 ? 4 : 3); // has alpha channel?
for(y=0; y<height; ++y) {
int packet_idx;
for(packet_idx=0; packet_idx < num_packets; ++packet_idx) {
pic_packet_t *packet = &packets[packet_idx];
stbi_uc *dest = result+y*width*4;
switch (packet->type) {
default:
return epuc("bad format","packet has bad compression type");
case 0: {//uncompressed
int x;
for(x=0;x<width;++x, dest+=4)
if (!pic_readval(s,packet->channel,dest))
return 0;
break;
}
case 1://Pure RLE
{
int left=width, i;
while (left>0) {
stbi_uc count,value[4];
count=get8u(s);
if (at_eof(s)) return epuc("bad file","file too short (pure read count)");
if (count > left)
count = (stbi__uint8) left;
if (!pic_readval(s,packet->channel,value)) return 0;
for(i=0; i<count; ++i,dest+=4)
pic_copyval(packet->channel,dest,value);
left -= count;
}
}
break;
case 2: {//Mixed RLE
int left=width;
while (left>0) {
int count = get8(s), i;
if (at_eof(s)) return epuc("bad file","file too short (mixed read count)");
if (count >= 128) { // Repeated
stbi_uc value[4];
int i;
if (count==128)
count = get16(s);
else
count -= 127;
if (count > left)
return epuc("bad file","scanline overrun");
if (!pic_readval(s,packet->channel,value))
return 0;
for(i=0;i<count;++i, dest += 4)
pic_copyval(packet->channel,dest,value);
} else { // Raw
++count;
if (count>left) return epuc("bad file","scanline overrun");
for(i=0;i<count;++i, dest+=4)
if (!pic_readval(s,packet->channel,dest))
return 0;
}
left-=count;
}
break;
}
}
}
}
return result;
}
static stbi_uc *pic_load(stbi *s,int *px,int *py,int *comp,int req_comp)
{
stbi_uc *result;
int i, x,y;
for (i=0; i<92; ++i)
get8(s);
x = get16(s);
y = get16(s);
if (at_eof(s)) return epuc("bad file","file too short (pic header)");
if ((1 << 28) / x < y) return epuc("too large", "Image too large to decode");
get32(s); //skip `ratio'
get16(s); //skip `fields'
get16(s); //skip `pad'
// intermediate buffer is RGBA
result = (stbi_uc *) malloc(x*y*4);
memset(result, 0xff, x*y*4);
if (!pic_load2(s,x,y,comp, result)) {
free(result);
result=0;
}
*px = x;
*py = y;
if (req_comp == 0) req_comp = *comp;
result=convert_format(result,4,req_comp,x,y);
return result;
}
static int stbi_pic_test(stbi *s)
{
int r = pic_test(s);
stbi_rewind(s);
return r;
}
static stbi_uc *stbi_pic_load(stbi *s, int *x, int *y, int *comp, int req_comp)
{
return pic_load(s,x,y,comp,req_comp);
}
// *************************************************************************************************
// GIF loader -- public domain by Jean-Marc Lienher -- simplified/shrunk by stb
typedef struct stbi_gif_lzw_struct {
stbi__int16 prefix;
stbi__uint8 first;
stbi__uint8 suffix;
} stbi_gif_lzw;
typedef struct stbi_gif_struct
{
int w,h;
stbi_uc *out; // output buffer (always 4 components)
int flags, bgindex, ratio, transparent, eflags;
stbi__uint8 pal[256][4];
stbi__uint8 lpal[256][4];
stbi_gif_lzw codes[4096];
stbi__uint8 *color_table;
int parse, step;
int lflags;
int start_x, start_y;
int max_x, max_y;
int cur_x, cur_y;
int line_size;
} stbi_gif;
static int gif_test(stbi *s)
{
int sz;
if (get8(s) != 'G' || get8(s) != 'I' || get8(s) != 'F' || get8(s) != '8') return 0;
sz = get8(s);
if (sz != '9' && sz != '7') return 0;
if (get8(s) != 'a') return 0;
return 1;
}
static int stbi_gif_test(stbi *s)
{
int r = gif_test(s);
stbi_rewind(s);
return r;
}
static void stbi_gif_parse_colortable(stbi *s, stbi__uint8 pal[256][4], int num_entries, int transp)
{
int i;
for (i=0; i < num_entries; ++i) {
pal[i][2] = get8u(s);
pal[i][1] = get8u(s);
pal[i][0] = get8u(s);
pal[i][3] = transp ? 0 : 255;
}
}
static int stbi_gif_header(stbi *s, stbi_gif *g, int *comp, int is_info)
{
stbi__uint8 version;
if (get8(s) != 'G' || get8(s) != 'I' || get8(s) != 'F' || get8(s) != '8')
return e("not GIF", "Corrupt GIF");
version = get8u(s);
if (version != '7' && version != '9') return e("not GIF", "Corrupt GIF");
if (get8(s) != 'a') return e("not GIF", "Corrupt GIF");
failure_reason = "";
g->w = get16le(s);
g->h = get16le(s);
g->flags = get8(s);
g->bgindex = get8(s);
g->ratio = get8(s);
g->transparent = -1;
if (comp != 0) *comp = 4; // can't actually tell whether it's 3 or 4 until we parse the comments
if (is_info) return 1;
if (g->flags & 0x80)
stbi_gif_parse_colortable(s,g->pal, 2 << (g->flags & 7), -1);
return 1;
}
static int stbi_gif_info_raw(stbi *s, int *x, int *y, int *comp)
{
stbi_gif g;
if (!stbi_gif_header(s, &g, comp, 1)) {
stbi_rewind( s );
return 0;
}
if (x) *x = g.w;
if (y) *y = g.h;
return 1;
}
static void stbi_out_gif_code(stbi_gif *g, stbi__uint16 code)
{
stbi__uint8 *p, *c;
// recurse to decode the prefixes, since the linked-list is backwards,
// and working backwards through an interleaved image would be nasty
if (g->codes[code].prefix >= 0)
stbi_out_gif_code(g, g->codes[code].prefix);
if (g->cur_y >= g->max_y) return;
p = &g->out[g->cur_x + g->cur_y];
c = &g->color_table[g->codes[code].suffix * 4];
if (c[3] >= 128) {
p[0] = c[2];
p[1] = c[1];
p[2] = c[0];
p[3] = c[3];
}
g->cur_x += 4;
if (g->cur_x >= g->max_x) {
g->cur_x = g->start_x;
g->cur_y += g->step;
while (g->cur_y >= g->max_y && g->parse > 0) {
g->step = (1 << g->parse) * g->line_size;
g->cur_y = g->start_y + (g->step >> 1);
--g->parse;
}
}
}
static stbi__uint8 *stbi_process_gif_raster(stbi *s, stbi_gif *g)
{
stbi__uint8 lzw_cs;
stbi__int32 len, code;
stbi__uint32 first;
stbi__int32 codesize, codemask, avail, oldcode, bits, valid_bits, clear;
stbi_gif_lzw *p;
lzw_cs = get8u(s);
clear = 1 << lzw_cs;
first = 1;
codesize = lzw_cs + 1;
codemask = (1 << codesize) - 1;
bits = 0;
valid_bits = 0;
for (code = 0; code < clear; code++) {
g->codes[code].prefix = -1;
g->codes[code].first = (stbi__uint8) code;
g->codes[code].suffix = (stbi__uint8) code;
}
// support no starting clear code
avail = clear+2;
oldcode = -1;
len = 0;
for(;;) {
if (valid_bits < codesize) {
if (len == 0) {
len = get8(s); // start new block
if (len == 0)
return g->out;
}
--len;
bits |= (stbi__int32) get8(s) << valid_bits;
valid_bits += 8;
} else {
stbi__int32 code = bits & codemask;
bits >>= codesize;
valid_bits -= codesize;
// @OPTIMIZE: is there some way we can accelerate the non-clear path?
if (code == clear) { // clear code
codesize = lzw_cs + 1;
codemask = (1 << codesize) - 1;
avail = clear + 2;
oldcode = -1;
first = 0;
} else if (code == clear + 1) { // end of stream code
skip(s, len);
while ((len = get8(s)) > 0)
skip(s,len);
return g->out;
} else if (code <= avail) {
if (first) return epuc("no clear code", "Corrupt GIF");
if (oldcode >= 0) {
p = &g->codes[avail++];
if (avail > 4096) return epuc("too many codes", "Corrupt GIF");
p->prefix = (stbi__int16) oldcode;
p->first = g->codes[oldcode].first;
p->suffix = (code == avail) ? p->first : g->codes[code].first;
} else if (code == avail)
return epuc("illegal code in raster", "Corrupt GIF");
stbi_out_gif_code(g, (stbi__uint16) code);
if ((avail & codemask) == 0 && avail <= 0x0FFF) {
codesize++;
codemask = (1 << codesize) - 1;
}
oldcode = code;
} else {
return epuc("illegal code in raster", "Corrupt GIF");
}
}
}
}
static void stbi_fill_gif_background(stbi_gif *g)
{
int i;
stbi__uint8 *c = g->pal[g->bgindex];
// @OPTIMIZE: write a dword at a time
for (i = 0; i < g->w * g->h * 4; i += 4) {
stbi__uint8 *p = &g->out[i];
p[0] = c[2];
p[1] = c[1];
p[2] = c[0];
p[3] = c[3];
}
}
// this function is designed to support animated gifs, although stb_image doesn't support it
static stbi__uint8 *stbi_gif_load_next(stbi *s, stbi_gif *g, int *comp, int req_comp)
{
int i;
stbi__uint8 *old_out = 0;
if (g->out == 0) {
if (!stbi_gif_header(s, g, comp,0)) return 0; // failure_reason set by stbi_gif_header
g->out = (stbi__uint8 *) malloc(4 * g->w * g->h);
if (g->out == 0) return epuc("outofmem", "Out of memory");
stbi_fill_gif_background(g);
} else {
// animated-gif-only path
if (((g->eflags & 0x1C) >> 2) == 3) {
old_out = g->out;
g->out = (stbi__uint8 *) malloc(4 * g->w * g->h);
if (g->out == 0) return epuc("outofmem", "Out of memory");
memcpy(g->out, old_out, g->w*g->h*4);
}
}
for (;;) {
switch (get8(s)) {
case 0x2C: /* Image Descriptor */
{
stbi__int32 x, y, w, h;
stbi__uint8 *o;
x = get16le(s);
y = get16le(s);
w = get16le(s);
h = get16le(s);
if (((x + w) > (g->w)) || ((y + h) > (g->h)))
return epuc("bad Image Descriptor", "Corrupt GIF");
g->line_size = g->w * 4;
g->start_x = x * 4;
g->start_y = y * g->line_size;
g->max_x = g->start_x + w * 4;
g->max_y = g->start_y + h * g->line_size;
g->cur_x = g->start_x;
g->cur_y = g->start_y;
g->lflags = get8(s);
if (g->lflags & 0x40) {
g->step = 8 * g->line_size; // first interlaced spacing
g->parse = 3;
} else {
g->step = g->line_size;
g->parse = 0;
}
if (g->lflags & 0x80) {
stbi_gif_parse_colortable(s,g->lpal, 2 << (g->lflags & 7), g->eflags & 0x01 ? g->transparent : -1);
g->color_table = (stbi__uint8 *) g->lpal;
} else if (g->flags & 0x80) {
for (i=0; i < 256; ++i) // @OPTIMIZE: reset only the previous transparent
g->pal[i][3] = 255;
if (g->transparent >= 0 && (g->eflags & 0x01))
g->pal[g->transparent][3] = 0;
g->color_table = (stbi__uint8 *) g->pal;
} else
return epuc("missing color table", "Corrupt GIF");
o = stbi_process_gif_raster(s, g);
if (o == NULL) return NULL;
if (req_comp && req_comp != 4)
o = convert_format(o, 4, req_comp, g->w, g->h);
return o;
}
case 0x21: // Comment Extension.
{
int len;
if (get8(s) == 0xF9) { // Graphic Control Extension.
len = get8(s);
if (len == 4) {
g->eflags = get8(s);
get16le(s); // delay
g->transparent = get8(s);
} else {
skip(s, len);
break;
}
}
while ((len = get8(s)) != 0)
skip(s, len);
break;
}
case 0x3B: // gif stream termination code
return (stbi__uint8 *) 1;
default:
return epuc("unknown code", "Corrupt GIF");
}
}
}
static stbi_uc *stbi_gif_load(stbi *s, int *x, int *y, int *comp, int req_comp)
{
stbi__uint8 *u = 0;
stbi_gif g={0};
u = stbi_gif_load_next(s, &g, comp, req_comp);
if (u == (void *) 1) u = 0; // end of animated gif marker
if (u) {
*x = g.w;
*y = g.h;
}
return u;
}
static int stbi_gif_info(stbi *s, int *x, int *y, int *comp)
{
return stbi_gif_info_raw(s,x,y,comp);
}
// *************************************************************************************************
// Radiance RGBE HDR loader
// originally by Nicolas Schulz
#ifndef STBI_NO_HDR
static int hdr_test(stbi *s)
{
const char *signature = "#?RADIANCE\n";
int i;
for (i=0; signature[i]; ++i)
if (get8(s) != signature[i])
return 0;
return 1;
}
static int stbi_hdr_test(stbi* s)
{
int r = hdr_test(s);
stbi_rewind(s);
return r;
}
#define HDR_BUFLEN 1024
static char *hdr_gettoken(stbi *z, char *buffer)
{
int len=0;
char c = '\0';
c = (char) get8(z);
while (!at_eof(z) && c != '\n') {
buffer[len++] = c;
if (len == HDR_BUFLEN-1) {
// flush to end of line
while (!at_eof(z) && get8(z) != '\n')
;
break;
}
c = (char) get8(z);
}
buffer[len] = 0;
return buffer;
}
static void hdr_convert(float *output, stbi_uc *input, int req_comp)
{
if ( input[3] != 0 ) {
float f1;
// Exponent
f1 = (float) ldexp(1.0f, input[3] - (int)(128 + 8));
if (req_comp <= 2)
output[0] = (input[0] + input[1] + input[2]) * f1 / 3;
else {
output[0] = input[0] * f1;
output[1] = input[1] * f1;
output[2] = input[2] * f1;
}
if (req_comp == 2) output[1] = 1;
if (req_comp == 4) output[3] = 1;
} else {
switch (req_comp) {
case 4: output[3] = 1; /* fallthrough */
case 3: output[0] = output[1] = output[2] = 0;
break;
case 2: output[1] = 1; /* fallthrough */
case 1: output[0] = 0;
break;
}
}
}
static float *hdr_load(stbi *s, int *x, int *y, int *comp, int req_comp)
{
char buffer[HDR_BUFLEN];
char *token;
int valid = 0;
int width, height;
stbi_uc *scanline;
float *hdr_data;
int len;
unsigned char count, value;
int i, j, k, c1,c2, z;
// Check identifier
if (strcmp(hdr_gettoken(s,buffer), "#?RADIANCE") != 0)
return epf("not HDR", "Corrupt HDR image");
// Parse header
for(;;) {
token = hdr_gettoken(s,buffer);
if (token[0] == 0) break;
if (strcmp(token, "FORMAT=32-bit_rle_rgbe") == 0) valid = 1;
}
if (!valid) return epf("unsupported format", "Unsupported HDR format");
// Parse width and height
// can't use sscanf() if we're not using stdio!
token = hdr_gettoken(s,buffer);
if (strncmp(token, "-Y ", 3)) return epf("unsupported data layout", "Unsupported HDR format");
token += 3;
height = (int) strtol(token, &token, 10);
while (*token == ' ') ++token;
if (strncmp(token, "+X ", 3)) return epf("unsupported data layout", "Unsupported HDR format");
token += 3;
width = (int) strtol(token, NULL, 10);
*x = width;
*y = height;
*comp = 3;
if (req_comp == 0) req_comp = 3;
// Read data
hdr_data = (float *) malloc(height * width * req_comp * sizeof(float));
// Load image data
// image data is stored as some number of sca
if ( width < 8 || width >= 32768) {
// Read flat data
for (j=0; j < height; ++j) {
for (i=0; i < width; ++i) {
stbi_uc rgbe[4];
main_decode_loop:
getn(s, rgbe, 4);
hdr_convert(hdr_data + j * width * req_comp + i * req_comp, rgbe, req_comp);
}
}
} else {
// Read RLE-encoded data
scanline = NULL;
for (j = 0; j < height; ++j) {
c1 = get8(s);
c2 = get8(s);
len = get8(s);
if (c1 != 2 || c2 != 2 || (len & 0x80)) {
// not run-length encoded, so we have to actually use THIS data as a decoded
// pixel (note this can't be a valid pixel--one of RGB must be >= 128)
stbi__uint8 rgbe[4];
rgbe[0] = (stbi__uint8) c1;
rgbe[1] = (stbi__uint8) c2;
rgbe[2] = (stbi__uint8) len;
rgbe[3] = (stbi__uint8) get8u(s);
hdr_convert(hdr_data, rgbe, req_comp);
i = 1;
j = 0;
free(scanline);
goto main_decode_loop; // yes, this makes no sense
}
len <<= 8;
len |= get8(s);
if (len != width) { free(hdr_data); free(scanline); return epf("invalid decoded scanline length", "corrupt HDR"); }
if (scanline == NULL) scanline = (stbi_uc *) malloc(width * 4);
for (k = 0; k < 4; ++k) {
i = 0;
while (i < width) {
count = get8u(s);
if (count > 128) {
// Run
value = get8u(s);
count -= 128;
for (z = 0; z < count; ++z)
scanline[i++ * 4 + k] = value;
} else {
// Dump
for (z = 0; z < count; ++z)
scanline[i++ * 4 + k] = get8u(s);
}
}
}
for (i=0; i < width; ++i)
hdr_convert(hdr_data+(j*width + i)*req_comp, scanline + i*4, req_comp);
}
free(scanline);
}
return hdr_data;
}
static float *stbi_hdr_load(stbi *s, int *x, int *y, int *comp, int req_comp)
{
return hdr_load(s,x,y,comp,req_comp);
}
static int stbi_hdr_info(stbi *s, int *x, int *y, int *comp)
{
char buffer[HDR_BUFLEN];
char *token;
int valid = 0;
if (strcmp(hdr_gettoken(s,buffer), "#?RADIANCE") != 0) {
stbi_rewind( s );
return 0;
}
for(;;) {
token = hdr_gettoken(s,buffer);
if (token[0] == 0) break;
if (strcmp(token, "FORMAT=32-bit_rle_rgbe") == 0) valid = 1;
}
if (!valid) {
stbi_rewind( s );
return 0;
}
token = hdr_gettoken(s,buffer);
if (strncmp(token, "-Y ", 3)) {
stbi_rewind( s );
return 0;
}
token += 3;
*y = (int) strtol(token, &token, 10);
while (*token == ' ') ++token;
if (strncmp(token, "+X ", 3)) {
stbi_rewind( s );
return 0;
}
token += 3;
*x = (int) strtol(token, NULL, 10);
*comp = 3;
return 1;
}
#endif // STBI_NO_HDR
static int stbi_bmp_info(stbi *s, int *x, int *y, int *comp)
{
int hsz;
if (get8(s) != 'B' || get8(s) != 'M') {
stbi_rewind( s );
return 0;
}
skip(s,12);
hsz = get32le(s);
if (hsz != 12 && hsz != 40 && hsz != 56 && hsz != 108) {
stbi_rewind( s );
return 0;
}
if (hsz == 12) {
*x = get16le(s);
*y = get16le(s);
} else {
*x = get32le(s);
*y = get32le(s);
}
if (get16le(s) != 1) {
stbi_rewind( s );
return 0;
}
*comp = get16le(s) / 8;
return 1;
}
static int stbi_psd_info(stbi *s, int *x, int *y, int *comp)
{
int channelCount;
if (get32(s) != 0x38425053) {
stbi_rewind( s );
return 0;
}
if (get16(s) != 1) {
stbi_rewind( s );
return 0;
}
skip(s, 6);
channelCount = get16(s);
if (channelCount < 0 || channelCount > 16) {
stbi_rewind( s );
return 0;
}
*y = get32(s);
*x = get32(s);
if (get16(s) != 8) {
stbi_rewind( s );
return 0;
}
if (get16(s) != 3) {
stbi_rewind( s );
return 0;
}
*comp = 4;
return 1;
}
static int stbi_pic_info(stbi *s, int *x, int *y, int *comp)
{
int act_comp=0,num_packets=0,chained;
pic_packet_t packets[10];
skip(s, 92);
*x = get16(s);
*y = get16(s);
if (at_eof(s)) return 0;
if ( (*x) != 0 && (1 << 28) / (*x) < (*y)) {
stbi_rewind( s );
return 0;
}
skip(s, 8);
do {
pic_packet_t *packet;
if (num_packets==sizeof(packets)/sizeof(packets[0]))
return 0;
packet = &packets[num_packets++];
chained = get8(s);
packet->size = get8u(s);
packet->type = get8u(s);
packet->channel = get8u(s);
act_comp |= packet->channel;
if (at_eof(s)) {
stbi_rewind( s );
return 0;
}
if (packet->size != 8) {
stbi_rewind( s );
return 0;
}
} while (chained);
*comp = (act_comp & 0x10 ? 4 : 3);
return 1;
}
static int stbi_info_main(stbi *s, int *x, int *y, int *comp)
{
if (stbi_jpeg_info(s, x, y, comp))
return 1;
if (stbi_png_info(s, x, y, comp))
return 1;
if (stbi_gif_info(s, x, y, comp))
return 1;
if (stbi_bmp_info(s, x, y, comp))
return 1;
if (stbi_psd_info(s, x, y, comp))
return 1;
if (stbi_pic_info(s, x, y, comp))
return 1;
#ifndef STBI_NO_HDR
if (stbi_hdr_info(s, x, y, comp))
return 1;
#endif
// test tga last because it's a crappy test!
if (stbi_tga_info(s, x, y, comp))
return 1;
return e("unknown image type", "Image not of any known type, or corrupt");
}
#ifndef STBI_NO_STDIO
int stbi_info(char const *filename, int *x, int *y, int *comp)
{
FILE *f = fopen(filename, "rb");
int result;
if (!f) return e("can't fopen", "Unable to open file");
result = stbi_info_from_file(f, x, y, comp);
fclose(f);
return result;
}
int stbi_info_from_file(FILE *f, int *x, int *y, int *comp)
{
int r;
stbi s;
long pos = ftell(f);
start_file(&s, f);
r = stbi_info_main(&s,x,y,comp);
fseek(f,pos,SEEK_SET);
return r;
}
#endif // !STBI_NO_STDIO
int stbi_info_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *comp)
{
stbi s;
start_mem(&s,buffer,len);
return stbi_info_main(&s,x,y,comp);
}
int stbi_info_from_callbacks(stbi_io_callbacks const *c, void *user, int *x, int *y, int *comp)
{
stbi s;
start_callbacks(&s, (stbi_io_callbacks *) c, user);
return stbi_info_main(&s,x,y,comp);
}
#endif // STBI_HEADER_FILE_ONLY
#if !defined(STBI_NO_STDIO) && defined(_MSC_VER) && _MSC_VER >= 1400
#pragma warning(pop)
#endif
/*
revision history:
1.35 (2014-05-27)
various warnings
fix broken STBI_SIMD path
fix bug where stbi_load_from_file no longer left file pointer in correct place
fix broken non-easy path for 32-bit BMP (possibly never used)
1.34 (unknown)
use STBI_NOTUSED in resample_row_generic(), fix one more leak in tga failure case
1.33 (2011-07-14)
make stbi_is_hdr work in STBI_NO_HDR (as specified), minor compiler-friendly improvements
1.32 (2011-07-13)
support for "info" function for all supported filetypes (SpartanJ)
1.31 (2011-06-20)
a few more leak fixes, bug in PNG handling (SpartanJ)
1.30 (2011-06-11)
added ability to load files via callbacks to accomidate custom input streams (Ben Wenger)
removed deprecated format-specific test/load functions
removed support for installable file formats (stbi_loader) -- would have been broken for IO callbacks anyway
error cases in bmp and tga give messages and don't leak (Raymond Barbiero, grisha)
fix inefficiency in decoding 32-bit BMP (David Woo)
1.29 (2010-08-16)
various warning fixes from Aurelien Pocheville
1.28 (2010-08-01)
fix bug in GIF palette transparency (SpartanJ)
1.27 (2010-08-01)
cast-to-stbi__uint8 to fix warnings
1.26 (2010-07-24)
fix bug in file buffering for PNG reported by SpartanJ
1.25 (2010-07-17)
refix trans_data warning (Won Chun)
1.24 (2010-07-12)
perf improvements reading from files on platforms with lock-heavy fgetc()
minor perf improvements for jpeg
deprecated type-specific functions so we'll get feedback if they're needed
attempt to fix trans_data warning (Won Chun)
1.23 fixed bug in iPhone support
1.22 (2010-07-10)
removed image *writing* support
stbi_info support from Jetro Lauha
GIF support from Jean-Marc Lienher
iPhone PNG-extensions from James Brown
warning-fixes from Nicolas Schulz and Janez Zemva (i.e. Janez (U+017D)emva)
1.21 fix use of 'stbi__uint8' in header (reported by jon blow)
1.20 added support for Softimage PIC, by Tom Seddon
1.19 bug in interlaced PNG corruption check (found by ryg)
1.18 2008-08-02
fix a threading bug (local mutable static)
1.17 support interlaced PNG
1.16 major bugfix - convert_format converted one too many pixels
1.15 initialize some fields for thread safety
1.14 fix threadsafe conversion bug
header-file-only version (#define STBI_HEADER_FILE_ONLY before including)
1.13 threadsafe
1.12 const qualifiers in the API
1.11 Support installable IDCT, colorspace conversion routines
1.10 Fixes for 64-bit (don't use "unsigned long")
optimized upsampling by Fabian "ryg" Giesen
1.09 Fix format-conversion for PSD code (bad global variables!)
1.08 Thatcher Ulrich's PSD code integrated by Nicolas Schulz
1.07 attempt to fix C++ warning/errors again
1.06 attempt to fix C++ warning/errors again
1.05 fix TGA loading to return correct *comp and use good luminance calc
1.04 default float alpha is 1, not 255; use 'void *' for stbi_image_free
1.03 bugfixes to STBI_NO_STDIO, STBI_NO_HDR
1.02 support for (subset of) HDR files, float interface for preferred access to them
1.01 fix bug: possible bug in handling right-side up bmps... not sure
fix bug: the stbi_bmp_load() and stbi_tga_load() functions didn't work at all
1.00 interface to zlib that skips zlib header
0.99 correct handling of alpha in palette
0.98 TGA loader by lonesock; dynamically add loaders (untested)
0.97 jpeg errors on too large a file; also catch another malloc failure
0.96 fix detection of invalid v value - particleman@mollyrocket forum
0.95 during header scan, seek to markers in case of padding
0.94 STBI_NO_STDIO to disable stdio usage; rename all #defines the same
0.93 handle jpegtran output; verbose errors
0.92 read 4,8,16,24,32-bit BMP files of several formats
0.91 output 24-bit Windows 3.0 BMP files
0.90 fix a few more warnings; bump version number to approach 1.0
0.61 bugfixes due to Marc LeBlanc, Christopher Lloyd
0.60 fix compiling as c++
0.59 fix warnings: merge Dave Moore's -Wall fixes
0.58 fix bug: zlib uncompressed mode len/nlen was wrong endian
0.57 fix bug: jpg last huffman symbol before marker was >9 bits but less than 16 available
0.56 fix bug: zlib uncompressed mode len vs. nlen
0.55 fix bug: restart_interval not initialized to 0
0.54 allow NULL for 'int *comp'
0.53 fix bug in png 3->4; speedup png decoding
0.52 png handles req_comp=3,4 directly; minor cleanup; jpeg comments
0.51 obey req_comp requests, 1-component jpegs return as 1-component,
on 'test' only check type, not whether we support this variant
0.50 first released version
*/
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