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113 lines
3.6 KiB
C
113 lines
3.6 KiB
C
/*
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* Copyright (C) 1999-2001, 2008, 2016 Free Software Foundation, Inc.
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* This file is part of the GNU LIBICONV Library.
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*
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* The GNU LIBICONV Library is free software; you can redistribute it
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* and/or modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* The GNU LIBICONV Library is distributed in the hope that it will be
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* useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with the GNU LIBICONV Library; see the file COPYING.LIB.
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* If not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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* UTF-16
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*/
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/* Specification: RFC 2781 */
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/* Here we accept FFFE/FEFF marks as endianness indicators everywhere
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in the stream, not just at the beginning. (This is contrary to what
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RFC 2781 section 3.2 specifies, but it allows concatenation of byte
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sequences to work flawlessly, while disagreeing with the RFC behaviour
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only for strings containing U+FEFF characters, which is quite rare.)
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The default is big-endian. */
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/* The state is 0 if big-endian, 1 if little-endian. */
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static int
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utf16_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, size_t n)
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{
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state_t state = conv->istate;
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int count = 0;
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for (; n >= 2 && count <= RET_COUNT_MAX && count <= INT_MAX-2;) {
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ucs4_t wc = (state ? s[0] + (s[1] << 8) : (s[0] << 8) + s[1]);
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if (wc == 0xfeff) {
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} else if (wc == 0xfffe) {
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state ^= 1;
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} else if (wc >= 0xd800 && wc < 0xdc00) {
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if (n >= 4) {
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ucs4_t wc2 = (state ? s[2] + (s[3] << 8) : (s[2] << 8) + s[3]);
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if (!(wc2 >= 0xdc00 && wc2 < 0xe000))
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goto ilseq;
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*pwc = 0x10000 + ((wc - 0xd800) << 10) + (wc2 - 0xdc00);
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conv->istate = state;
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return count+4;
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} else
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break;
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} else if (wc >= 0xdc00 && wc < 0xe000) {
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goto ilseq;
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} else {
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*pwc = wc;
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conv->istate = state;
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return count+2;
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}
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s += 2; n -= 2; count += 2;
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}
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conv->istate = state;
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return RET_TOOFEW(count);
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ilseq:
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conv->istate = state;
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return RET_SHIFT_ILSEQ(count);
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}
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/* We output UTF-16 in big-endian order, with byte-order mark.
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See RFC 2781 section 3.3 for a rationale: Some document formats
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mandate a BOM; the file concatenation issue is not so severe as
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long as the above utf16_mbtowc function is used. */
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/* The state is 0 at the beginning, 1 after the BOM has been written. */
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static int
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utf16_wctomb (conv_t conv, unsigned char *r, ucs4_t wc, size_t n)
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{
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if (wc != 0xfffe && !(wc >= 0xd800 && wc < 0xe000)) {
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int count = 0;
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if (!conv->ostate) {
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if (n >= 2) {
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r[0] = 0xFE;
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r[1] = 0xFF;
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r += 2; n -= 2; count += 2;
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} else
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return RET_TOOSMALL;
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}
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if (wc < 0x10000) {
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if (n >= 2) {
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r[0] = (unsigned char) (wc >> 8);
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r[1] = (unsigned char) wc;
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conv->ostate = 1;
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return count+2;
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} else
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return RET_TOOSMALL;
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}
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else if (wc < 0x110000) {
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if (n >= 4) {
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ucs4_t wc1 = 0xd800 + ((wc - 0x10000) >> 10);
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ucs4_t wc2 = 0xdc00 + ((wc - 0x10000) & 0x3ff);
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r[0] = (unsigned char) (wc1 >> 8);
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r[1] = (unsigned char) wc1;
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r[2] = (unsigned char) (wc2 >> 8);
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r[3] = (unsigned char) wc2;
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conv->ostate = 1;
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return count+4;
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} else
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return RET_TOOSMALL;
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}
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}
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return RET_ILUNI;
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}
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