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Annotation of embedaddon/libiconv/lib/utf16.h, revision 1.1.1.2

1.1       misho       1: /*
1.1.1.2 ! misho       2:  * Copyright (C) 1999-2001, 2008, 2016 Free Software Foundation, Inc.
1.1       misho       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.
1.1.1.2 ! misho      17:  * If not, see <https://www.gnu.org/licenses/>.
1.1       misho      18:  */
                     19: 
                     20: /*
                     21:  * UTF-16
                     22:  */
                     23: 
                     24: /* Specification: RFC 2781 */
                     25: 
                     26: /* Here we accept FFFE/FEFF marks as endianness indicators everywhere
                     27:    in the stream, not just at the beginning. (This is contrary to what
                     28:    RFC 2781 section 3.2 specifies, but it allows concatenation of byte
                     29:    sequences to work flawlessly, while disagreeing with the RFC behaviour
                     30:    only for strings containing U+FEFF characters, which is quite rare.)
                     31:    The default is big-endian. */
                     32: /* The state is 0 if big-endian, 1 if little-endian. */
                     33: static int
1.1.1.2 ! misho      34: utf16_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, size_t n)
1.1       misho      35: {
                     36:   state_t state = conv->istate;
                     37:   int count = 0;
1.1.1.2 ! misho      38:   for (; n >= 2 && count <= RET_COUNT_MAX && count <= INT_MAX-2;) {
1.1       misho      39:     ucs4_t wc = (state ? s[0] + (s[1] << 8) : (s[0] << 8) + s[1]);
                     40:     if (wc == 0xfeff) {
                     41:     } else if (wc == 0xfffe) {
                     42:       state ^= 1;
                     43:     } else if (wc >= 0xd800 && wc < 0xdc00) {
                     44:       if (n >= 4) {
                     45:         ucs4_t wc2 = (state ? s[2] + (s[3] << 8) : (s[2] << 8) + s[3]);
                     46:         if (!(wc2 >= 0xdc00 && wc2 < 0xe000))
                     47:           goto ilseq;
                     48:         *pwc = 0x10000 + ((wc - 0xd800) << 10) + (wc2 - 0xdc00);
                     49:         conv->istate = state;
                     50:         return count+4;
                     51:       } else
                     52:         break;
                     53:     } else if (wc >= 0xdc00 && wc < 0xe000) {
                     54:       goto ilseq;
                     55:     } else {
                     56:       *pwc = wc;
                     57:       conv->istate = state;
                     58:       return count+2;
                     59:     }
                     60:     s += 2; n -= 2; count += 2;
                     61:   }
                     62:   conv->istate = state;
                     63:   return RET_TOOFEW(count);
                     64: 
                     65: ilseq:
                     66:   conv->istate = state;
                     67:   return RET_SHIFT_ILSEQ(count);
                     68: }
                     69: 
                     70: /* We output UTF-16 in big-endian order, with byte-order mark.
                     71:    See RFC 2781 section 3.3 for a rationale: Some document formats
                     72:    mandate a BOM; the file concatenation issue is not so severe as
                     73:    long as the above utf16_mbtowc function is used. */
                     74: /* The state is 0 at the beginning, 1 after the BOM has been written. */
                     75: static int
1.1.1.2 ! misho      76: utf16_wctomb (conv_t conv, unsigned char *r, ucs4_t wc, size_t n)
1.1       misho      77: {
                     78:   if (wc != 0xfffe && !(wc >= 0xd800 && wc < 0xe000)) {
                     79:     int count = 0;
                     80:     if (!conv->ostate) {
                     81:       if (n >= 2) {
                     82:         r[0] = 0xFE;
                     83:         r[1] = 0xFF;
                     84:         r += 2; n -= 2; count += 2;
                     85:       } else
                     86:         return RET_TOOSMALL;
                     87:     }
                     88:     if (wc < 0x10000) {
                     89:       if (n >= 2) {
                     90:         r[0] = (unsigned char) (wc >> 8);
                     91:         r[1] = (unsigned char) wc;
                     92:         conv->ostate = 1;
                     93:         return count+2;
                     94:       } else
                     95:         return RET_TOOSMALL;
                     96:     }
                     97:     else if (wc < 0x110000) {
                     98:       if (n >= 4) {
                     99:         ucs4_t wc1 = 0xd800 + ((wc - 0x10000) >> 10);
                    100:         ucs4_t wc2 = 0xdc00 + ((wc - 0x10000) & 0x3ff);
                    101:         r[0] = (unsigned char) (wc1 >> 8);
                    102:         r[1] = (unsigned char) wc1;
                    103:         r[2] = (unsigned char) (wc2 >> 8);
                    104:         r[3] = (unsigned char) wc2;
                    105:         conv->ostate = 1;
                    106:         return count+4;
                    107:       } else
                    108:         return RET_TOOSMALL;
                    109:     }
                    110:   }
                    111:   return RET_ILUNI;
                    112: }