mirror of
https://github.com/netsurf-browser/netsurf
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282 lines
7.1 KiB
C
282 lines
7.1 KiB
C
/*
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* This file is part of NetSurf, http://netsurf.sourceforge.net/
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* Licensed under the GNU General Public License,
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* http://www.opensource.org/licenses/gpl-license
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* Copyright 2005 John M Bell <jmb202@ecs.soton.ac.uk>
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*/
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/**
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* \file UTF-8 manipulation functions (implementation)
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*/
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#include <assert.h>
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#include <stdlib.h>
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#include <string.h>
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#include <iconv.h>
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#include "netsurf/utils/utf8.h"
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static char *utf8_convert(const char *string, size_t len, const char *from,
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const char *to);
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/**
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* Convert a UTF-8 multibyte sequence into a single UCS4 character
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*
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* Encoding of UCS values outside the UTF-16 plane has been removed from
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* RFC3629. This function conforms to RFC2279, however, as it is possible
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* that the platform specific keyboard input handler will generate a UCS4
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* value outside the UTF-16 plane.
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*
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* \param s The sequence to process
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* \param l Length of sequence
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* \return UCS4 character
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*/
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size_t utf8_to_ucs4(const char *s, size_t l)
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{
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size_t c = 0;
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if (!s)
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assert(0);
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else if (l > 0 && *s < 0x80)
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c = *s;
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else if (l > 1 && (*s & 0xE0) == 0xC0 && (*(s+1) & 0xC0) == 0x80)
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c = ((*s & 0x1F) << 6) | (*(s+1) & 0x3F);
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else if (l > 2 && (*s & 0xF0) == 0xE0 && (*(s+1) & 0xC0) == 0x80 &&
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(*(s+2) & 0xC0) == 0x80)
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c = ((*s & 0x0F) << 12) | ((*(s+1) & 0x3F) << 6) |
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(*(s+2) & 0x3F);
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else if (l > 3 && (*s & 0xF8) == 0xF0 && (*(s+1) & 0xC0) == 0x80 &&
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(*(s+2) & 0xC0) == 0x80 && (*(s+3) & 0xC0) == 0x80)
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c = ((*s & 0x0F) << 18) | ((*(s+1) & 0x3F) << 12) |
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((*(s+2) & 0x3F) << 6) | (*(s+3) & 0x3F);
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else if (l > 4 && (*s & 0xFC) == 0xF8 && (*(s+1) & 0xC0) == 0x80 &&
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(*(s+2) & 0xC0) == 0x80 && (*(s+3) & 0xC0) == 0x80 &&
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(*(s+4) & 0xC0) == 0x80)
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c = ((*s & 0x0F) << 24) | ((*(s+1) & 0x3F) << 18) |
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((*(s+2) & 0x3F) << 12) | ((*(s+3) & 0x3F) << 6) |
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(*(s+4) & 0x3F);
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else if (l > 5 && (*s & 0xFE) == 0xFC && (*(s+1) & 0xC0) == 0x80 &&
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(*(s+2) & 0xC0) == 0x80 && (*(s+3) & 0xC0) == 0x80 &&
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(*(s+4) & 0xC0) == 0x80 && (*(s+5) & 0xC0) == 0x80)
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c = ((*s & 0x0F) << 28) | ((*(s+1) & 0x3F) << 24) |
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((*(s+2) & 0x3F) << 18) | ((*(s+3) & 0x3F) << 12) |
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((*(s+4) & 0x3F) << 6) | (*(s+5) & 0x3F);
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else
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assert(0);
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return c;
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}
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/**
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* Convert a single UCS4 character into a UTF-8 multibyte sequence
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*
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* Encoding of UCS values outside the UTF-16 plane has been removed from
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* RFC3629. This function conforms to RFC2279, however, as it is possible
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* that the platform specific keyboard input handler will generate a UCS4
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* value outside the UTF-16 plane.
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*
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* \param c The character to process (0 <= c <= 0x7FFFFFFF)
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* \param s Pointer to 6 byte long output buffer
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* \return Length of multibyte sequence
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*/
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size_t utf8_from_ucs4(size_t c, char *s)
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{
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size_t l = 0;
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if (c > 0x7FFFFFFF)
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assert(0);
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else if (c < 0x80) {
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*s = (char)c;
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l = 1;
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}
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else if (c < 0x800) {
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*s = 0xC0 | ((c >> 6) & 0x1F);
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*(s+1) = 0x80 | (c & 0x3F);
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l = 2;
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}
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else if (c < 0x10000) {
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*s = 0xE0 | ((c >> 12) & 0xF);
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*(s+1) = 0x80 | ((c >> 6) & 0x3F);
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*(s+2) = 0x80 | (c & 0x3F);
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l = 3;
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}
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else if (c < 0x200000) {
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*s = 0xF0 | ((c >> 18) & 0x7);
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*(s+1) = 0x80 | ((c >> 12) & 0x3F);
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*(s+2) = 0x80 | ((c >> 6) & 0x3F);
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*(s+3) = 0x80 | (c & 0x3F);
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l = 4;
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}
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else if (c < 0x4000000) {
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*s = 0xF8 | ((c >> 24) & 0x3);
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*(s+1) = 0x80 | ((c >> 18) & 0x3F);
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*(s+2) = 0x80 | ((c >> 12) & 0x3F);
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*(s+3) = 0x80 | ((c >> 6) & 0x3F);
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*(s+4) = 0x80 | (c & 0x3F);
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l = 5;
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}
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else if (c <= 0x7FFFFFFF) {
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*s = 0xFC | ((c >> 30) & 0x1);
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*(s+1) = 0x80 | ((c >> 24) & 0x3F);
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*(s+2) = 0x80 | ((c >> 18) & 0x3F);
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*(s+3) = 0x80 | ((c >> 12) & 0x3F);
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*(s+4) = 0x80 | ((c >> 6) & 0x3F);
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*(s+5) = 0x80 | (c & 0x3F);
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l = 6;
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}
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return l;
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}
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/**
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* Calculate the length (in characters) of a NULL-terminated UTF-8 string
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*
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* \param s The string
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* \return Length of string
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*/
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size_t utf8_length(const char *s)
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{
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const char *__s = s;
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int l = 0;
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while (*__s != '\0') {
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if ((*__s & 0x80) == 0x00)
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__s += 1;
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else if ((*__s & 0xE0) == 0xC0)
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__s += 2;
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else if ((*__s & 0xF0) == 0xE0)
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__s += 3;
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else if ((*__s & 0xF8) == 0xF0)
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__s += 4;
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else if ((*__s & 0xFC) == 0xF8)
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__s += 5;
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else if ((*__s & 0xFE) == 0xFC)
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__s += 6;
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else
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assert(0);
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l++;
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}
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return l;
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}
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/**
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* Find previous legal UTF-8 char in string
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*
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* \param s The string
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* \param o Offset in the string to start at
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* \return Offset of first byte of previous legal character
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*/
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size_t utf8_prev(const char *s, size_t o)
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{
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while (o != 0 && !(((s[--o] & 0x80) == 0x00) ||
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((s[o] & 0xC0) == 0xC0)))
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/* do nothing */;
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return o;
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}
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/**
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* Find next legal UTF-8 char in string
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*
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* \param s The string
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* \param l Maximum offset in string
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* \param o Offset in the string to start at
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* \return Offset of first byte of next legal character
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*/
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size_t utf8_next(const char *s, size_t l, size_t o)
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{
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while (o != l && !(((s[++o] & 0x80) == 0x00) ||
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((s[o] & 0xC0) == 0xC0)))
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/* do nothing */;
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return o;
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}
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/**
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* Convert a UTF8 string into the named encoding
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*
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* \param string The NULL-terminated string to convert
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* \param encname The encoding name (suitable for passing to iconv)
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* \param len Length of input string to consider (in bytes), or 0
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* \return Pointer to converted string (on heap) or NULL on error
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*/
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char *utf8_to_enc(const char *string, const char *encname, size_t len)
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{
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return utf8_convert(string, len, "UTF-8", encname);
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}
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/**
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* Convert a UTF8 string into the named encoding
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*
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* \param string The NULL-terminated string to convert
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* \param encname The encoding name (suitable for passing to iconv)
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* \param len Length of input string to consider (in bytes), or 0
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* \return Pointer to converted string (on heap) or NULL on error
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*/
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char *utf8_from_enc(const char *string, const char *encname, size_t len)
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{
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return utf8_convert(string, len, encname, "UTF-8");
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}
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/**
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* Convert a string from one encoding to another
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*
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* \param string The NULL-terminated string to convert
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* \param len Length of input string to consider (in bytes)
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* \param from The encoding name to convert from
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* \param to The encoding name to convert to
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* \return Pointer to converted string (on heap) or NULL on error
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*/
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char *utf8_convert(const char *string, size_t len, const char *from,
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const char *to)
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{
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iconv_t cd;
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char *ret, *temp, *out, *in;
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size_t slen, rlen;
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if (!string || !from || !to)
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return NULL;
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in = (char *)string;
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cd = iconv_open(to, from);
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if (cd == (iconv_t)-1)
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return NULL;
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slen = len ? len : strlen(string);
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/* Worst case = ACSII -> UCS4, so allocate an output buffer
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* 4 times larger than the input buffer, and add 4 bytes at
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* the end for the NULL terminator
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*/
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rlen = slen * 4 + 4;
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temp = out = calloc(rlen, sizeof(char));
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if (!out) {
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iconv_close(cd);
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return NULL;
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}
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/* perform conversion */
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if (iconv(cd, &in, &slen, &out, &rlen) == (size_t)-1) {
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free(temp);
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iconv_close(cd);
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return NULL;
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}
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iconv_close(cd);
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if (rlen > 64 /* allow 64bytes wasted space */) {
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/* and allocate a more sensibly sized output buffer */
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ret = calloc(out - temp + 4, sizeof(char));
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memcpy(ret, temp, out - temp);
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free(temp);
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}
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else
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ret = temp;
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return ret;
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}
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