110 lines
3.5 KiB
C
110 lines
3.5 KiB
C
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2012, 2014.
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This file is part of the Sortix C Library.
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The Sortix C Library is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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The Sortix C Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
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wchar/wcrtomb.c
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Convert a wide character to a multibyte sequence.
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*******************************************************************************/
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#include <errno.h>
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#include <stdlib.h>
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#include <wchar.h>
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static
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size_t utf8_wcrtomb(char* restrict s, wchar_t wc, mbstate_t* restrict ps)
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{
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(void) ps;
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// The definition of UTF-8 prohibits encoding character numbers between
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// U+D800 and U+DFFF, which are reserved for use with the UTF-16 encoding
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// form (as surrogate pairs) and do not directly represent characters.
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if ( 0xD800 <= wc && wc <= 0xDFFF )
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return errno = EILSEQ, (size_t) -1;
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// RFC 3629 limits UTF-8 to 0x0 through 0x10FFFF.
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if ( 0x10FFFF <= wc )
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return errno = EILSEQ, (size_t) -1;
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size_t index = 0;
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if ( wc < (1 << (7)) ) /* 0xxxxxxx */
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{
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s[index++] = 0b00000000 | (wc >> 0 & 0b01111111);
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return index;
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}
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if ( wc < (1 << (5 + 1 * 6)) ) /* 110xxxxx 10xxxxxx^1 */
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{
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s[index++] = 0b11000000 | (wc >> 6 & 0b00011111);
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s[index++] = 0b10000000 | (wc >> 0 & 0b00111111);
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return index;
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}
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if ( wc < (1 << (4 + 2 * 6)) ) /* 1110xxxx 10xxxxxx^2 */
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{
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s[index++] = 0b11100000 | (wc >> 2*6 & 0b00001111);
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s[index++] = 0b10000000 | (wc >> 1*6 & 0b00111111);
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s[index++] = 0b10000000 | (wc >> 0*6 & 0b00111111);
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return index;
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}
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if ( wc < (1 << (3 + 3 * 6)) ) /* 11110xxx 10xxxxxx^3 */
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{
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s[index++] = 0b11110000 | (wc >> 3*6 & 0b00000111);
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s[index++] = 0b10000000 | (wc >> 2*6 & 0b00111111);
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s[index++] = 0b10000000 | (wc >> 1*6 & 0b00111111);
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s[index++] = 0b10000000 | (wc >> 0*6 & 0b00111111);
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return index;
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}
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#if 0 /* 5-byte and 6-byte sequences are forbidden by RFC 3629 */
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if ( wc < (1 << (2 + 4 * 6)) ) /* 111110xx 10xxxxxx^4 */
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{
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s[index++] = 0b11111000 | (wc >> 4*6 & 0b00000011);
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s[index++] = 0b10000000 | (wc >> 3*6 & 0b00111111);
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s[index++] = 0b10000000 | (wc >> 2*6 & 0b00111111);
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s[index++] = 0b10000000 | (wc >> 1*6 & 0b00111111);
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s[index++] = 0b10000000 | (wc >> 0*6 & 0b00111111);
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return index;
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}
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if ( wc < (1 << (1 + 5 * 6)) ) /* 111110xx 10xxxxxx^5 */
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{
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s[index++] = 0b11111100 | (wc >> 5*6 & 0b00000001);
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s[index++] = 0b10000000 | (wc >> 4*6 & 0b00111111);
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s[index++] = 0b10000000 | (wc >> 3*6 & 0b00111111);
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s[index++] = 0b10000000 | (wc >> 2*6 & 0b00111111);
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s[index++] = 0b10000000 | (wc >> 1*6 & 0b00111111);
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s[index++] = 0b10000000 | (wc >> 0*6 & 0b00111111);
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return index;
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}
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#endif
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return errno = EILSEQ; return (size_t) -1;
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}
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size_t wcrtomb(char* restrict s, wchar_t wc, mbstate_t* restrict ps)
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{
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char internal_buffer[MB_CUR_MAX];
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if ( !s )
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wc = L'\0', s = internal_buffer;
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// TODO: Verify whether the current locale is UTF-8.
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return utf8_wcrtomb(s, wc, ps);
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}
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