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125 lines
3.5 KiB
C
125 lines
3.5 KiB
C
/* Multibyte to UTF-8 conversion.
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Copyright (C) 2022-2024 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 <assert.h>
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#include <dlfcn.h>
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#include <errno.h>
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#include <gconv.h>
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#include <uchar.h>
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#include <wcsmbsload.h>
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#ifndef EILSEQ
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# define EILSEQ EINVAL
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#endif
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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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mbrtoc8 (char8_t *pc8, const char *s, size_t n, mbstate_t *ps)
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{
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/* This implementation depends on the converter invoked by mbrtowc 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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yet to be written and uses ps->__value to store those code units. */
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if (ps == NULL)
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ps = &state;
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/* If state indicates that trailing code units are yet to be written, write
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those first regardless of whether 's' is a null pointer. */
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if (ps->__count & 0x80000000)
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{
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/* ps->__value.__wchb[3] stores the index of the next code unit to
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write. Code units are stored in reverse order. */
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size_t i = ps->__value.__wchb[3];
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if (pc8 != NULL)
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{
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*pc8 = ps->__value.__wchb[i];
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}
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if (i == 0)
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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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else
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--ps->__value.__wchb[3];
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return -3;
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}
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if (s == NULL)
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{
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/* if 's' is a null pointer, behave as if a null pointer was passed for
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'pc8', an empty string was passed for 's', and 1 passed for 'n'. */
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pc8 = NULL;
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s = "";
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n = 1;
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}
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wchar_t wc;
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size_t result;
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result = mbrtowc (&wc, s, n, ps);
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if (result <= n)
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{
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if (wc <= 0x7F)
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{
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if (pc8 != NULL)
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*pc8 = wc;
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}
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else if (wc <= 0x7FF)
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{
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if (pc8 != NULL)
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*pc8 = 0xC0 + ((wc >> 6) & 0x1F);
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ps->__value.__wchb[0] = 0x80 + (wc & 0x3F);
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ps->__value.__wchb[3] = 0;
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ps->__count |= 0x80000000;
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}
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else if (wc <= 0xFFFF)
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{
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if (pc8 != NULL)
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*pc8 = 0xE0 + ((wc >> 12) & 0x0F);
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ps->__value.__wchb[1] = 0x80 + ((wc >> 6) & 0x3F);
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ps->__value.__wchb[0] = 0x80 + (wc & 0x3F);
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ps->__value.__wchb[3] = 1;
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ps->__count |= 0x80000000;
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}
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else if (wc <= 0x10FFFF)
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{
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if (pc8 != NULL)
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*pc8 = 0xF0 + ((wc >> 18) & 0x07);
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ps->__value.__wchb[2] = 0x80 + ((wc >> 12) & 0x3F);
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ps->__value.__wchb[1] = 0x80 + ((wc >> 6) & 0x3F);
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ps->__value.__wchb[0] = 0x80 + (wc & 0x3F);
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ps->__value.__wchb[3] = 2;
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ps->__count |= 0x80000000;
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}
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}
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if (result == 0 && wc != 0)
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{
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/* mbrtowc() never returns -3. When a MB sequence converts to multiple
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WCs, no input is consumed when writing the subsequent WCs resulting
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in a result of 0 even if a null character wasn't written. */
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result = -3;
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}
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return result;
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}
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