Annotation of XML/encoding.c, revision 1.1
1.1 ! daniel 1: /*
! 2: * encoding.c : implements the encoding conversion functions needed for XML
! 3: *
! 4: * Related specs:
! 5: * rfc2044 (UTF-8 and UTF-16) F. Yergeau Alis Technologies
! 6: * [ISO-10646] UTF-8 and UTF-16 in Annexes
! 7: * [ISO-8859-1] ISO Latin-1 characters codes.
! 8: * [UNICODE] The Unicode Consortium, "The Unicode Standard --
! 9: * Worldwide Character Encoding -- Version 1.0", Addison-
! 10: * Wesley, Volume 1, 1991, Volume 2, 1992. UTF-8 is
! 11: * described in Unicode Technical Report #4.
! 12: * [US-ASCII] Coded Character Set--7-bit American Standard Code for
! 13: * Information Interchange, ANSI X3.4-1986.
! 14: *
! 15: * Original code from "Martin J. Duerst" <duerst@w3.org>
! 16: *
! 17: * See Copyright for the status of this software.
! 18: *
! 19: * $Id: encoding.c,v 1.2 1998/10/20 06:14:14 veillard Exp $
! 20: *
! 21: * Daniel.Veillard@w3.org
! 22: */
! 23:
! 24: #include "encoding.h"
! 25:
! 26: /**
! 27: * isolat1ToUTF8:
! 28: * @out: a pointer ot an array of bytes to store the result
! 29: * @outlen: the lenght of @out
! 30: * @in: a pointer ot an array of ISO Latin 1 chars
! 31: * @inlen: the lenght of @in
! 32: *
! 33: * Take a block of ISO Latin 1 chars in and try to convert it to an UTF-8
! 34: * block of chars out.
! 35: * return values: number of byte written, or -1 by lack of space.
! 36: */
! 37: int
! 38: isolat1ToUTF8(unsigned char* out, int outlen, unsigned char* in, int inlen)
! 39: {
! 40: unsigned char* outstart= out;
! 41: unsigned char* outend= out+outlen;
! 42: unsigned char* inend= in+inlen;
! 43: unsigned char c;
! 44:
! 45: while (in < inend) {
! 46: c= *in++;
! 47: if (c < 0x80) {
! 48: if (out >= outend) return -1;
! 49: *out++ = c;
! 50: }
! 51: else {
! 52: if (out >= outend) return -1;
! 53: *out++ = 0xC0 | (c >> 6);
! 54: if (out >= outend) return -1;
! 55: *out++ = 0x80 | (0x3F & c);
! 56: }
! 57: }
! 58: return out-outstart;
! 59: }
! 60:
! 61: /**
! 62: * UTF8Toisolat1:
! 63: * @out: a pointer ot an array of bytes to store the result
! 64: * @outlen: the lenght of @out
! 65: * @in: a pointer ot an array of UTF-8 chars
! 66: * @inlen: the lenght of @in
! 67: *
! 68: * Take a block of UTF-8 chars in and try to convert it to an ISO Latin 1
! 69: * block of chars out.
! 70: * TODO: need a fallback mechanism ...
! 71: * return values: the number of byte written, or -1 by lack of space, or -2
! 72: * if the transcoding failed.
! 73: */
! 74: int
! 75: UTF8Toisolat1(unsigned char* out, int outlen, unsigned char* in, int inlen)
! 76: {
! 77: unsigned char* outstart= out;
! 78: unsigned char* outend= out+outlen;
! 79: unsigned char* inend= in+inlen;
! 80: unsigned char c;
! 81:
! 82: while (in < inend) {
! 83: c= *in++;
! 84: if (c < 0x80) {
! 85: if (out >= outend) return -1;
! 86: *out++= c;
! 87: }
! 88: else if (((c & 0xFE) == 0xC2) && in<inend) {
! 89: if (out >= outend) return -1;
! 90: *out++= ((c & 0x03) << 6) | (*in++ & 0x3F);
! 91: }
! 92: else return -2;
! 93: }
! 94: return out-outstart;
! 95: }
! 96:
! 97: /**
! 98: * UTF16ToUTF8:
! 99: * @out: a pointer ot an array of bytes to store the result
! 100: * @outlen: the lenght of @out
! 101: * @in: a pointer ot an array of UTF-16 chars (array of unsigned shorts)
! 102: * @inlen: the lenght of @in
! 103: *
! 104: * Take a block of UTF-16 ushorts in and try to convert it to an UTF-8
! 105: * block of chars out.
! 106: * return values: number of byte written, or -1 by lack of space.
! 107: */
! 108: int
! 109: UTF16ToUTF8(unsigned char* out, int outlen, unsigned short* in, int inlen)
! 110: {
! 111: unsigned char* outstart= out;
! 112: unsigned char* outend= out+outlen;
! 113: unsigned short* inend= in+inlen;
! 114: unsigned int c, d;
! 115: int bits;
! 116:
! 117: while (in < inend) {
! 118: c= *in++;
! 119: if ((c & 0xFC00) == 0xD800) { /* surrogates */
! 120: if ((in<inend) && (((d=*in++) & 0xFC00) == 0xDC00)) {
! 121: c &= 0x03FF;
! 122: c <<= 10;
! 123: c |= d & 0x03FF;
! 124: c += 0x10000;
! 125: }
! 126: else return -1;
! 127: }
! 128:
! 129: /* assertion: c is a single UTF-4 value */
! 130:
! 131: if (out >= outend) return -1;
! 132: if (c < 0x80) { *out++= c; bits= -6; }
! 133: else if (c < 0x800) { *out++= (c >> 6) | 0xC0; bits= 0; }
! 134: else if (c < 0x10000) { *out++= (c >> 12) | 0xE0; bits= 6; }
! 135: else { *out++= (c >> 18) | 0xF0; bits= 12; }
! 136:
! 137: for ( ; bits < 0; bits-= 6) {
! 138: if (out >= outend) return -1;
! 139: *out++= (c >> bits) & 0x3F;
! 140: }
! 141: }
! 142: return out-outstart;
! 143: }
! 144:
! 145: /**
! 146: * UTF8ToUTF16:
! 147: * @out: a pointer ot an array of shorts to store the result
! 148: * @outlen: the lenght of @out (number of shorts)
! 149: * @in: a pointer ot an array of UTF-8 chars
! 150: * @inlen: the lenght of @in
! 151: *
! 152: * Take a block of UTF-8 chars in and try to convert it to an UTF-16
! 153: * block of chars out.
! 154: * TODO: need a fallback mechanism ...
! 155: * return values: the number of byte written, or -1 by lack of space, or -2
! 156: * if the transcoding failed.
! 157: */
! 158: int
! 159: UTF8ToUTF16(unsigned short* out, int outlen, unsigned char* in, int inlen)
! 160: {
! 161: unsigned short* outstart= out;
! 162: unsigned short* outend= out+outlen;
! 163: unsigned char* inend= in+inlen;
! 164: unsigned int c, d, trailing;
! 165:
! 166: while (in < inend) {
! 167: d= *in++;
! 168: if (d < 0x80) { c= d; trailing= 0; }
! 169: else if (d < 0xC0) return -2; /* trailing byte in leading position */
! 170: else if (d < 0xE0) { c= d & 0x1F; trailing= 1; }
! 171: else if (d < 0xF0) { c= d & 0x0F; trailing= 2; }
! 172: else if (d < 0xF8) { c= d & 0x07; trailing= 3; }
! 173: else return -2; /* no chance for this in UTF-16 */
! 174:
! 175: for ( ; trailing; trailing--) {
! 176: if ((in >= inend) || (((d= *in++) & 0xC0) != 0x80)) return -1;
! 177: c <<= 6;
! 178: c |= d & 0x3F;
! 179: }
! 180:
! 181: /* assertion: c is a single UTF-4 value */
! 182: if (c < 0x10000) {
! 183: if (out >= outend) return -1;
! 184: *out++ = c;
! 185: }
! 186: else if (c < 0x110000) {
! 187: if (out+1 >= outend) return -1;
! 188: c -= 0x10000;
! 189: *out++ = 0xD800 | (c >> 10);
! 190: *out++ = 0xDC00 | (c & 0x03FF);
! 191: }
! 192: else return -1;
! 193: }
! 194: return out-outstart;
! 195: }
! 196:
! 197:
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