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libxml2/encoding.c
Daniel Veillard 011b63cb20 Release of libxml-1.1, Daniel.
1999-06-02 17:44:04 +00:00

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/*
* encoding.c : implements the encoding conversion functions needed for XML
*
* Related specs:
* rfc2044 (UTF-8 and UTF-16) F. Yergeau Alis Technologies
* [ISO-10646] UTF-8 and UTF-16 in Annexes
* [ISO-8859-1] ISO Latin-1 characters codes.
* [UNICODE] The Unicode Consortium, "The Unicode Standard --
* Worldwide Character Encoding -- Version 1.0", Addison-
* Wesley, Volume 1, 1991, Volume 2, 1992. UTF-8 is
* described in Unicode Technical Report #4.
* [US-ASCII] Coded Character Set--7-bit American Standard Code for
* Information Interchange, ANSI X3.4-1986.
*
* Original code from "Martin J. Duerst" <duerst@w3.org>
*
* See Copyright for the status of this software.
*
* Daniel.Veillard@w3.org
*/
#include <ctype.h>
#include "encoding.h"
/*
* From rfc2044: encoding of the Unicode values on UTF-8:
*
* UCS-4 range (hex.) UTF-8 octet sequence (binary)
* 0000 0000-0000 007F 0xxxxxxx
* 0000 0080-0000 07FF 110xxxxx 10xxxxxx
* 0000 0800-0000 FFFF 1110xxxx 10xxxxxx 10xxxxxx
*
* I hope we won't use values > 0xFFFF anytime soon !
*/
/**
* isolat1ToUTF8:
* @out: a pointer ot an array of bytes to store the result
* @outlen: the lenght of @out
* @in: a pointer ot an array of ISO Latin 1 chars
* @inlen: the lenght of @in
*
* Take a block of ISO Latin 1 chars in and try to convert it to an UTF-8
* block of chars out.
* Returns the number of byte written, or -1 by lack of space.
*/
int
isolat1ToUTF8(unsigned char* out, int outlen, unsigned char* in, int inlen)
{
unsigned char* outstart= out;
unsigned char* outend= out+outlen;
unsigned char* inend= in+inlen;
unsigned char c;
while (in < inend) {
c= *in++;
if (c < 0x80) {
if (out >= outend) return -1;
*out++ = c;
}
else {
if (out >= outend) return -1;
*out++ = 0xC0 | (c >> 6);
if (out >= outend) return -1;
*out++ = 0x80 | (0x3F & c);
}
}
return out-outstart;
}
/**
* UTF8Toisolat1:
* @out: a pointer ot an array of bytes to store the result
* @outlen: the lenght of @out
* @in: a pointer ot an array of UTF-8 chars
* @inlen: the lenght of @in
*
* Take a block of UTF-8 chars in and try to convert it to an ISO Latin 1
* block of chars out.
* TODO: need a fallback mechanism ...
* Returns the number of byte written, or -1 by lack of space, or -2
* if the transcoding failed.
*/
int
UTF8Toisolat1(unsigned char* out, int outlen, unsigned char* in, int inlen)
{
unsigned char* outstart= out;
unsigned char* outend= out+outlen;
unsigned char* inend= in+inlen;
unsigned char c;
while (in < inend) {
c= *in++;
if (c < 0x80) {
if (out >= outend) return -1;
*out++= c;
}
else if (((c & 0xFE) == 0xC2) && in<inend) {
if (out >= outend) return -1;
*out++= ((c & 0x03) << 6) | (*in++ & 0x3F);
}
else return -2;
}
return out-outstart;
}
/**
* UTF16ToUTF8:
* @out: a pointer ot an array of bytes to store the result
* @outlen: the lenght of @out
* @in: a pointer ot an array of UTF-16 chars (array of unsigned shorts)
* @inlen: the lenght of @in
*
* Take a block of UTF-16 ushorts in and try to convert it to an UTF-8
* block of chars out.
* Returns the number of byte written, or -1 by lack of space.
*/
int
UTF16ToUTF8(unsigned char* out, int outlen, unsigned short* in, int inlen)
{
unsigned char* outstart= out;
unsigned char* outend= out+outlen;
unsigned short* inend= in+inlen;
unsigned int c, d;
int bits;
while (in < inend) {
c= *in++;
if ((c & 0xFC00) == 0xD800) { /* surrogates */
if ((in<inend) && (((d=*in++) & 0xFC00) == 0xDC00)) {
c &= 0x03FF;
c <<= 10;
c |= d & 0x03FF;
c += 0x10000;
}
else return -1;
}
/* assertion: c is a single UTF-4 value */
if (out >= outend) return -1;
if (c < 0x80) { *out++= c; bits= -6; }
else if (c < 0x800) { *out++= (c >> 6) | 0xC0; bits= 0; }
else if (c < 0x10000) { *out++= (c >> 12) | 0xE0; bits= 6; }
else { *out++= (c >> 18) | 0xF0; bits= 12; }
for ( ; bits < 0; bits-= 6) {
if (out >= outend) return -1;
*out++= (c >> bits) & 0x3F;
}
}
return out-outstart;
}
/**
* UTF8ToUTF16:
* @out: a pointer ot an array of shorts to store the result
* @outlen: the lenght of @out (number of shorts)
* @in: a pointer ot an array of UTF-8 chars
* @inlen: the lenght of @in
*
* Take a block of UTF-8 chars in and try to convert it to an UTF-16
* block of chars out.
* TODO: need a fallback mechanism ...
* Returns the number of byte written, or -1 by lack of space, or -2
* if the transcoding failed.
*/
int
UTF8ToUTF16(unsigned short* out, int outlen, unsigned char* in, int inlen)
{
unsigned short* outstart= out;
unsigned short* outend= out+outlen;
unsigned char* inend= in+inlen;
unsigned int c, d, trailing;
while (in < inend) {
d= *in++;
if (d < 0x80) { c= d; trailing= 0; }
else if (d < 0xC0) return -2; /* trailing byte in leading position */
else if (d < 0xE0) { c= d & 0x1F; trailing= 1; }
else if (d < 0xF0) { c= d & 0x0F; trailing= 2; }
else if (d < 0xF8) { c= d & 0x07; trailing= 3; }
else return -2; /* no chance for this in UTF-16 */
for ( ; trailing; trailing--) {
if ((in >= inend) || (((d= *in++) & 0xC0) != 0x80)) return -1;
c <<= 6;
c |= d & 0x3F;
}
/* assertion: c is a single UTF-4 value */
if (c < 0x10000) {
if (out >= outend) return -1;
*out++ = c;
}
else if (c < 0x110000) {
if (out+1 >= outend) return -1;
c -= 0x10000;
*out++ = 0xD800 | (c >> 10);
*out++ = 0xDC00 | (c & 0x03FF);
}
else return -1;
}
return out-outstart;
}
/**
* xmlDetectCharEncoding:
* @in: a pointer to the first bytes of the XML entity, must be at least
* 4 bytes long.
*
* Guess the encoding of the entity using the first bytes of the entity content
* accordingly of the non-normative appendix F of the XML-1.0 recommendation.
*
* Returns one of the XML_CHAR_ENCODING_... values.
*/
xmlCharEncoding
xmlDetectCharEncoding(const unsigned char* in)
{
if ((in[0] == 0x00) && (in[1] == 0x00) &&
(in[2] == 0x00) && (in[3] == 0x3C))
return(XML_CHAR_ENCODING_UCS4BE);
if ((in[0] == 0x3C) && (in[1] == 0x00) &&
(in[2] == 0x00) && (in[3] == 0x00))
return(XML_CHAR_ENCODING_UCS4LE);
if ((in[0] == 0x00) && (in[1] == 0x00) &&
(in[2] == 0x3C) && (in[3] == 0x00))
return(XML_CHAR_ENCODING_UCS4_2143);
if ((in[0] == 0x00) && (in[1] == 0x3C) &&
(in[2] == 0x00) && (in[3] == 0x00))
return(XML_CHAR_ENCODING_UCS4_3412);
if ((in[0] == 0xFE) && (in[1] == 0xFF))
return(XML_CHAR_ENCODING_UTF16BE);
if ((in[0] == 0xFF) && (in[1] == 0xFE))
return(XML_CHAR_ENCODING_UTF16LE);
if ((in[0] == 0x4C) && (in[1] == 0x6F) &&
(in[2] == 0xA7) && (in[3] == 0x94))
return(XML_CHAR_ENCODING_EBCDIC);
if ((in[0] == 0x3C) && (in[1] == 0x3F) &&
(in[2] == 0x78) && (in[3] == 0x6D))
return(XML_CHAR_ENCODING_UTF8);
return(XML_CHAR_ENCODING_NONE);
}
/**
* xmlParseCharEncoding:
* @name: the encoding name as parsed, in UTF-8 format (ASCCI actually)
*
* Conpare the string to the known encoding schemes already known. Note
* that the comparison is case insensitive accordingly to the section
* [XML] 4.3.3 Character Encoding in Entities.
*
* Returns one of the XML_CHAR_ENCODING_... values or XML_CHAR_ENCODING_NONE
* if not recognized.
*/
xmlCharEncoding
xmlParseCharEncoding(const char* name)
{
char upper[500];
int i;
for (i = 0;i < 499;i++) {
upper[i] = toupper(name[i]);
if (upper[i] == 0) break;
}
upper[i] = 0;
if (!strcmp(upper, "")) return(XML_CHAR_ENCODING_NONE);
if (!strcmp(upper, "UTF-8")) return(XML_CHAR_ENCODING_UTF8);
if (!strcmp(upper, "UTF8")) return(XML_CHAR_ENCODING_UTF8);
/*
* NOTE: if we were able to parse this, the endianness of UTF16 is
* already found and in use
*/
if (!strcmp(upper, "UTF-16")) return(XML_CHAR_ENCODING_UTF16LE);
if (!strcmp(upper, "UTF16")) return(XML_CHAR_ENCODING_UTF16LE);
if (!strcmp(upper, "ISO-10646-UCS-2")) return(XML_CHAR_ENCODING_UCS2);
if (!strcmp(upper, "UCS-2")) return(XML_CHAR_ENCODING_UCS2);
if (!strcmp(upper, "UCS2")) return(XML_CHAR_ENCODING_UCS2);
/*
* NOTE: if we were able to parse this, the endianness of UCS4 is
* already found and in use
*/
if (!strcmp(upper, "ISO-10646-UCS-4")) return(XML_CHAR_ENCODING_UCS4LE);
if (!strcmp(upper, "UCS-4")) return(XML_CHAR_ENCODING_UCS4LE);
if (!strcmp(upper, "UCS4")) return(XML_CHAR_ENCODING_UCS4LE);
if (!strcmp(upper, "ISO-8859-1")) return(XML_CHAR_ENCODING_8859_1);
if (!strcmp(upper, "ISO-LATIN-1")) return(XML_CHAR_ENCODING_8859_1);
if (!strcmp(upper, "ISO LATIN 1")) return(XML_CHAR_ENCODING_8859_1);
if (!strcmp(upper, "ISO-8859-2")) return(XML_CHAR_ENCODING_8859_2);
if (!strcmp(upper, "ISO-LATIN-2")) return(XML_CHAR_ENCODING_8859_2);
if (!strcmp(upper, "ISO LATIN 2")) return(XML_CHAR_ENCODING_8859_2);
if (!strcmp(upper, "ISO-8859-3")) return(XML_CHAR_ENCODING_8859_3);
if (!strcmp(upper, "ISO-8859-4")) return(XML_CHAR_ENCODING_8859_4);
if (!strcmp(upper, "ISO-8859-5")) return(XML_CHAR_ENCODING_8859_5);
if (!strcmp(upper, "ISO-8859-6")) return(XML_CHAR_ENCODING_8859_6);
if (!strcmp(upper, "ISO-8859-7")) return(XML_CHAR_ENCODING_8859_7);
if (!strcmp(upper, "ISO-8859-8")) return(XML_CHAR_ENCODING_8859_8);
if (!strcmp(upper, "ISO-8859-9")) return(XML_CHAR_ENCODING_8859_9);
if (!strcmp(upper, "ISO-2022-JP")) return(XML_CHAR_ENCODING_2022_JP);
if (!strcmp(upper, "Shift_JIS")) return(XML_CHAR_ENCODING_SHIFT_JIS);
if (!strcmp(upper, "EUC-JP")) return(XML_CHAR_ENCODING_EUC_JP);
return(XML_CHAR_ENCODING_ERROR);
}
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