133 lines
3.5 KiB
C
133 lines
3.5 KiB
C
/* UTF-8 to multibyte conversion.
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Copyright (C) 2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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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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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <uchar.h>
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#include <wchar.h>
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/* This is the private state used if PS is NULL. */
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static mbstate_t state;
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size_t
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c8rtomb (char *s, char8_t c8, mbstate_t *ps)
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{
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/* This implementation depends on the converter invoked by wcrtomb not
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needing to retain state in either the top most bit of ps->__count or
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in ps->__value between invocations. This implementation uses the
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top most bit of ps->__count to indicate that trailing code units are
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expected and uses ps->__value to store previously seen code units. */
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wchar_t wc;
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if (ps == NULL)
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ps = &state;
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if (s == NULL)
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{
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/* if 's' is a null pointer, behave as if u8'\0' was passed as 'c8'. If
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this occurs for an incomplete code unit sequence, then an error will
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be reported below. */
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c8 = u8""[0];
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}
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if (! (ps->__count & 0x80000000))
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{
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/* Initial state. */
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if ((c8 >= 0x80 && c8 <= 0xC1) || c8 >= 0xF5)
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{
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/* An invalid lead code unit. */
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__set_errno (EILSEQ);
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return -1;
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}
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if (c8 >= 0xC2)
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{
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/* A valid lead code unit. */
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ps->__count |= 0x80000000;
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ps->__value.__wchb[0] = c8;
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ps->__value.__wchb[3] = 1;
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return 0;
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}
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/* A single byte (ASCII) code unit. */
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wc = c8;
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}
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else
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{
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char8_t cu1 = ps->__value.__wchb[0];
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if (ps->__value.__wchb[3] == 1)
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{
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/* A single lead code unit was previously seen. */
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if ((c8 < 0x80 || c8 > 0xBF)
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|| (cu1 == 0xE0 && c8 < 0xA0)
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|| (cu1 == 0xED && c8 > 0x9F)
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|| (cu1 == 0xF0 && c8 < 0x90)
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|| (cu1 == 0xF4 && c8 > 0x8F))
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{
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/* An invalid second code unit. */
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__set_errno (EILSEQ);
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return -1;
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}
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if (cu1 >= 0xE0)
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{
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/* A three or four code unit sequence. */
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ps->__value.__wchb[1] = c8;
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++ps->__value.__wchb[3];
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return 0;
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}
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wc = ((cu1 & 0x1F) << 6)
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+ (c8 & 0x3F);
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}
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else
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{
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char8_t cu2 = ps->__value.__wchb[1];
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/* A three or four byte code unit sequence. */
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if (c8 < 0x80 || c8 > 0xBF)
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{
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/* An invalid third or fourth code unit. */
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__set_errno (EILSEQ);
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return -1;
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}
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if (ps->__value.__wchb[3] == 2 && cu1 >= 0xF0)
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{
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/* A four code unit sequence. */
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ps->__value.__wchb[2] = c8;
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++ps->__value.__wchb[3];
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return 0;
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}
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if (cu1 < 0xF0)
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{
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wc = ((cu1 & 0x0F) << 12)
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+ ((cu2 & 0x3F) << 6)
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+ (c8 & 0x3F);
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}
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else
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{
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char8_t cu3 = ps->__value.__wchb[2];
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wc = ((cu1 & 0x07) << 18)
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+ ((cu2 & 0x3F) << 12)
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+ ((cu3 & 0x3F) << 6)
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+ (c8 & 0x3F);
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}
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}
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ps->__count &= 0x7fffffff;
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ps->__value.__wch = 0;
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}
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return wcrtomb (s, wc, ps);
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}
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