NetBSD/lib/libz/inflate.c
cgd 9118c05a03 RCS ID police: add NetBSD RCS IDs to everything. Since it was imported with
normal RCS IDs apparently unmodified (i.e. they were clobbered), remove
the normal Id tags so they cause fewer conflicts later.
1996-09-13 00:29:49 +00:00

348 lines
8.6 KiB
C

/* $NetBSD: inflate.c,v 1.2 1996/09/13 00:30:34 cgd Exp $ */
/* inflate.c -- zlib interface to inflate modules
* Copyright (C) 1995-1996 Mark Adler
* For conditions of distribution and use, see copyright notice in zlib.h
*/
#include "zutil.h"
#include "infblock.h"
struct inflate_blocks_state {int dummy;}; /* for buggy compilers */
/* inflate private state */
struct internal_state {
/* mode */
enum {
METHOD, /* waiting for method byte */
FLAG, /* waiting for flag byte */
DICT4, /* four dictionary check bytes to go */
DICT3, /* three dictionary check bytes to go */
DICT2, /* two dictionary check bytes to go */
DICT1, /* one dictionary check byte to go */
DICT0, /* waiting for inflateSetDictionary */
BLOCKS, /* decompressing blocks */
CHECK4, /* four check bytes to go */
CHECK3, /* three check bytes to go */
CHECK2, /* two check bytes to go */
CHECK1, /* one check byte to go */
DONE, /* finished check, done */
BAD} /* got an error--stay here */
mode; /* current inflate mode */
/* mode dependent information */
union {
uInt method; /* if FLAGS, method byte */
struct {
uLong was; /* computed check value */
uLong need; /* stream check value */
} check; /* if CHECK, check values to compare */
uInt marker; /* if BAD, inflateSync's marker bytes count */
} sub; /* submode */
/* mode independent information */
int nowrap; /* flag for no wrapper */
uInt wbits; /* log2(window size) (8..15, defaults to 15) */
inflate_blocks_statef
*blocks; /* current inflate_blocks state */
};
int inflateReset(z)
z_streamp z;
{
uLong c;
if (z == Z_NULL || z->state == Z_NULL)
return Z_STREAM_ERROR;
z->total_in = z->total_out = 0;
z->msg = Z_NULL;
z->state->mode = z->state->nowrap ? BLOCKS : METHOD;
inflate_blocks_reset(z->state->blocks, z, &c);
Trace((stderr, "inflate: reset\n"));
return Z_OK;
}
int inflateEnd(z)
z_streamp z;
{
uLong c;
if (z == Z_NULL || z->state == Z_NULL || z->zfree == Z_NULL)
return Z_STREAM_ERROR;
if (z->state->blocks != Z_NULL)
inflate_blocks_free(z->state->blocks, z, &c);
ZFREE(z, z->state);
z->state = Z_NULL;
Trace((stderr, "inflate: end\n"));
return Z_OK;
}
int inflateInit2_(z, w, version, stream_size)
z_streamp z;
int w;
const char *version;
int stream_size;
{
if (version == Z_NULL || version[0] != ZLIB_VERSION[0] ||
stream_size != sizeof(z_stream))
return Z_VERSION_ERROR;
/* initialize state */
if (z == Z_NULL)
return Z_STREAM_ERROR;
z->msg = Z_NULL;
if (z->zalloc == Z_NULL)
{
z->zalloc = zcalloc;
z->opaque = (voidpf)0;
}
if (z->zfree == Z_NULL) z->zfree = zcfree;
if ((z->state = (struct internal_state FAR *)
ZALLOC(z,1,sizeof(struct internal_state))) == Z_NULL)
return Z_MEM_ERROR;
z->state->blocks = Z_NULL;
/* handle undocumented nowrap option (no zlib header or check) */
z->state->nowrap = 0;
if (w < 0)
{
w = - w;
z->state->nowrap = 1;
}
/* set window size */
if (w < 8 || w > 15)
{
inflateEnd(z);
return Z_STREAM_ERROR;
}
z->state->wbits = (uInt)w;
/* create inflate_blocks state */
if ((z->state->blocks =
inflate_blocks_new(z, z->state->nowrap ? Z_NULL : adler32, (uInt)1 << w))
== Z_NULL)
{
inflateEnd(z);
return Z_MEM_ERROR;
}
Trace((stderr, "inflate: allocated\n"));
/* reset state */
inflateReset(z);
return Z_OK;
}
int inflateInit_(z, version, stream_size)
z_streamp z;
const char *version;
int stream_size;
{
return inflateInit2_(z, DEF_WBITS, version, stream_size);
}
#define NEEDBYTE {if(z->avail_in==0)return r;r=Z_OK;}
#define NEXTBYTE (z->avail_in--,z->total_in++,*z->next_in++)
int inflate(z, f)
z_streamp z;
int f;
{
int r;
uInt b;
if (z == Z_NULL || z->state == Z_NULL || z->next_in == Z_NULL || f < 0)
return Z_STREAM_ERROR;
r = Z_BUF_ERROR;
while (1) switch (z->state->mode)
{
case METHOD:
NEEDBYTE
if (((z->state->sub.method = NEXTBYTE) & 0xf) != Z_DEFLATED)
{
z->state->mode = BAD;
z->msg = (char*)"unknown compression method";
z->state->sub.marker = 5; /* can't try inflateSync */
break;
}
if ((z->state->sub.method >> 4) + 8 > z->state->wbits)
{
z->state->mode = BAD;
z->msg = (char*)"invalid window size";
z->state->sub.marker = 5; /* can't try inflateSync */
break;
}
z->state->mode = FLAG;
case FLAG:
NEEDBYTE
b = NEXTBYTE;
if (((z->state->sub.method << 8) + b) % 31)
{
z->state->mode = BAD;
z->msg = (char*)"incorrect header check";
z->state->sub.marker = 5; /* can't try inflateSync */
break;
}
Trace((stderr, "inflate: zlib header ok\n"));
if (!(b & PRESET_DICT))
{
z->state->mode = BLOCKS;
break;
}
z->state->mode = DICT4;
case DICT4:
NEEDBYTE
z->state->sub.check.need = (uLong)NEXTBYTE << 24;
z->state->mode = DICT3;
case DICT3:
NEEDBYTE
z->state->sub.check.need += (uLong)NEXTBYTE << 16;
z->state->mode = DICT2;
case DICT2:
NEEDBYTE
z->state->sub.check.need += (uLong)NEXTBYTE << 8;
z->state->mode = DICT1;
case DICT1:
NEEDBYTE
z->state->sub.check.need += (uLong)NEXTBYTE;
z->adler = z->state->sub.check.need;
z->state->mode = DICT0;
return Z_NEED_DICT;
case DICT0:
z->state->mode = BAD;
z->msg = (char*)"need dictionary";
z->state->sub.marker = 0; /* can try inflateSync */
return Z_STREAM_ERROR;
case BLOCKS:
r = inflate_blocks(z->state->blocks, z, r);
if (r == Z_DATA_ERROR)
{
z->state->mode = BAD;
z->state->sub.marker = 0; /* can try inflateSync */
break;
}
if (r != Z_STREAM_END)
return r;
r = Z_OK;
inflate_blocks_reset(z->state->blocks, z, &z->state->sub.check.was);
if (z->state->nowrap)
{
z->state->mode = DONE;
break;
}
z->state->mode = CHECK4;
case CHECK4:
NEEDBYTE
z->state->sub.check.need = (uLong)NEXTBYTE << 24;
z->state->mode = CHECK3;
case CHECK3:
NEEDBYTE
z->state->sub.check.need += (uLong)NEXTBYTE << 16;
z->state->mode = CHECK2;
case CHECK2:
NEEDBYTE
z->state->sub.check.need += (uLong)NEXTBYTE << 8;
z->state->mode = CHECK1;
case CHECK1:
NEEDBYTE
z->state->sub.check.need += (uLong)NEXTBYTE;
if (z->state->sub.check.was != z->state->sub.check.need)
{
z->state->mode = BAD;
z->msg = (char*)"incorrect data check";
z->state->sub.marker = 5; /* can't try inflateSync */
break;
}
Trace((stderr, "inflate: zlib check ok\n"));
z->state->mode = DONE;
case DONE:
return Z_STREAM_END;
case BAD:
return Z_DATA_ERROR;
default:
return Z_STREAM_ERROR;
}
}
int inflateSetDictionary(z, dictionary, dictLength)
z_streamp z;
const Bytef *dictionary;
uInt dictLength;
{
uInt length = dictLength;
if (z == Z_NULL || z->state == Z_NULL || z->state->mode != DICT0)
return Z_STREAM_ERROR;
if (adler32(1L, dictionary, dictLength) != z->adler) return Z_DATA_ERROR;
z->adler = 1L;
if (length >= ((uInt)1<<z->state->wbits))
{
length = (1<<z->state->wbits)-1;
dictionary += dictLength - length;
}
inflate_set_dictionary(z->state->blocks, dictionary, length);
z->state->mode = BLOCKS;
return Z_OK;
}
int inflateSync(z)
z_streamp z;
{
uInt n; /* number of bytes to look at */
Bytef *p; /* pointer to bytes */
uInt m; /* number of marker bytes found in a row */
uLong r, w; /* temporaries to save total_in and total_out */
/* set up */
if (z == Z_NULL || z->state == Z_NULL)
return Z_STREAM_ERROR;
if (z->state->mode != BAD)
{
z->state->mode = BAD;
z->state->sub.marker = 0;
}
if ((n = z->avail_in) == 0)
return Z_BUF_ERROR;
p = z->next_in;
m = z->state->sub.marker;
/* search */
while (n && m < 4)
{
if (*p == (Byte)(m < 2 ? 0 : 0xff))
m++;
else if (*p)
m = 0;
else
m = 4 - m;
p++, n--;
}
/* restore */
z->total_in += p - z->next_in;
z->next_in = p;
z->avail_in = n;
z->state->sub.marker = m;
/* return no joy or set up to restart on a new block */
if (m != 4)
return Z_DATA_ERROR;
r = z->total_in; w = z->total_out;
inflateReset(z);
z->total_in = r; z->total_out = w;
z->state->mode = BLOCKS;
return Z_OK;
}