Annotation of embedaddon/libiconv/lib/utf16.h, revision 1.1

1.1     ! misho       1: /*
        !             2:  * Copyright (C) 1999-2001, 2008 Free Software Foundation, Inc.
        !             3:  * This file is part of the GNU LIBICONV Library.
        !             4:  *
        !             5:  * The GNU LIBICONV Library is free software; you can redistribute it
        !             6:  * and/or modify it under the terms of the GNU Library General Public
        !             7:  * License as published by the Free Software Foundation; either version 2
        !             8:  * of the License, or (at your option) any later version.
        !             9:  *
        !            10:  * The GNU LIBICONV Library is distributed in the hope that it will be
        !            11:  * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
        !            12:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
        !            13:  * Library General Public License for more details.
        !            14:  *
        !            15:  * You should have received a copy of the GNU Library General Public
        !            16:  * License along with the GNU LIBICONV Library; see the file COPYING.LIB.
        !            17:  * If not, write to the Free Software Foundation, Inc., 51 Franklin Street,
        !            18:  * Fifth Floor, Boston, MA 02110-1301, USA.
        !            19:  */
        !            20: 
        !            21: /*
        !            22:  * UTF-16
        !            23:  */
        !            24: 
        !            25: /* Specification: RFC 2781 */
        !            26: 
        !            27: /* Here we accept FFFE/FEFF marks as endianness indicators everywhere
        !            28:    in the stream, not just at the beginning. (This is contrary to what
        !            29:    RFC 2781 section 3.2 specifies, but it allows concatenation of byte
        !            30:    sequences to work flawlessly, while disagreeing with the RFC behaviour
        !            31:    only for strings containing U+FEFF characters, which is quite rare.)
        !            32:    The default is big-endian. */
        !            33: /* The state is 0 if big-endian, 1 if little-endian. */
        !            34: static int
        !            35: utf16_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, int n)
        !            36: {
        !            37:   state_t state = conv->istate;
        !            38:   int count = 0;
        !            39:   for (; n >= 2;) {
        !            40:     ucs4_t wc = (state ? s[0] + (s[1] << 8) : (s[0] << 8) + s[1]);
        !            41:     if (wc == 0xfeff) {
        !            42:     } else if (wc == 0xfffe) {
        !            43:       state ^= 1;
        !            44:     } else if (wc >= 0xd800 && wc < 0xdc00) {
        !            45:       if (n >= 4) {
        !            46:         ucs4_t wc2 = (state ? s[2] + (s[3] << 8) : (s[2] << 8) + s[3]);
        !            47:         if (!(wc2 >= 0xdc00 && wc2 < 0xe000))
        !            48:           goto ilseq;
        !            49:         *pwc = 0x10000 + ((wc - 0xd800) << 10) + (wc2 - 0xdc00);
        !            50:         conv->istate = state;
        !            51:         return count+4;
        !            52:       } else
        !            53:         break;
        !            54:     } else if (wc >= 0xdc00 && wc < 0xe000) {
        !            55:       goto ilseq;
        !            56:     } else {
        !            57:       *pwc = wc;
        !            58:       conv->istate = state;
        !            59:       return count+2;
        !            60:     }
        !            61:     s += 2; n -= 2; count += 2;
        !            62:   }
        !            63:   conv->istate = state;
        !            64:   return RET_TOOFEW(count);
        !            65: 
        !            66: ilseq:
        !            67:   conv->istate = state;
        !            68:   return RET_SHIFT_ILSEQ(count);
        !            69: }
        !            70: 
        !            71: /* We output UTF-16 in big-endian order, with byte-order mark.
        !            72:    See RFC 2781 section 3.3 for a rationale: Some document formats
        !            73:    mandate a BOM; the file concatenation issue is not so severe as
        !            74:    long as the above utf16_mbtowc function is used. */
        !            75: /* The state is 0 at the beginning, 1 after the BOM has been written. */
        !            76: static int
        !            77: utf16_wctomb (conv_t conv, unsigned char *r, ucs4_t wc, int n)
        !            78: {
        !            79:   if (wc != 0xfffe && !(wc >= 0xd800 && wc < 0xe000)) {
        !            80:     int count = 0;
        !            81:     if (!conv->ostate) {
        !            82:       if (n >= 2) {
        !            83:         r[0] = 0xFE;
        !            84:         r[1] = 0xFF;
        !            85:         r += 2; n -= 2; count += 2;
        !            86:       } else
        !            87:         return RET_TOOSMALL;
        !            88:     }
        !            89:     if (wc < 0x10000) {
        !            90:       if (n >= 2) {
        !            91:         r[0] = (unsigned char) (wc >> 8);
        !            92:         r[1] = (unsigned char) wc;
        !            93:         conv->ostate = 1;
        !            94:         return count+2;
        !            95:       } else
        !            96:         return RET_TOOSMALL;
        !            97:     }
        !            98:     else if (wc < 0x110000) {
        !            99:       if (n >= 4) {
        !           100:         ucs4_t wc1 = 0xd800 + ((wc - 0x10000) >> 10);
        !           101:         ucs4_t wc2 = 0xdc00 + ((wc - 0x10000) & 0x3ff);
        !           102:         r[0] = (unsigned char) (wc1 >> 8);
        !           103:         r[1] = (unsigned char) wc1;
        !           104:         r[2] = (unsigned char) (wc2 >> 8);
        !           105:         r[3] = (unsigned char) wc2;
        !           106:         conv->ostate = 1;
        !           107:         return count+4;
        !           108:       } else
        !           109:         return RET_TOOSMALL;
        !           110:     }
        !           111:   }
        !           112:   return RET_ILUNI;
        !           113: }

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