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Annotation of embedaddon/libiconv/lib/utf16.h, revision 1.1.1.1

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: }