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112 lines
3.6 KiB
112 lines
3.6 KiB
/* |
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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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