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106 lines
3 KiB
C++
106 lines
3 KiB
C++
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/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2012.
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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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mbrtowc.cpp
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Convert a multibyte sequence to a wide character.
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*******************************************************************************/
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#include <errno.h>
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#include <stdint.h>
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#include <wchar.h>
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extern "C"
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size_t mbrtowc(wchar_t* restrict pwc, const char* restrict s, size_t n,
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mbstate_t* restrict /*ps*/)
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{
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if ( !s )
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{
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// TODO: Restore ps to initial state if currently valid.
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return 0;
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}
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uint8_t* buf = (uint8_t*) s;
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wchar_t ret = 0;
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size_t numbytes = 0;
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size_t sequence_len = 1;
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while ( numbytes < sequence_len )
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{
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if ( numbytes == n )
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{
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// TODO: Support restore through the mbstate_t!
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return (size_t) -2;
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}
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uint8_t b = buf[numbytes++];
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bool is_continuation = b >> (8-2) == 0b10;
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if ( 1 == numbytes && is_continuation )
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return errno = EILSEQ, (size_t) -1;
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if ( 2 <= numbytes && !is_continuation )
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return errno = EILSEQ, (size_t) -1;
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wchar_t new_bits;
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size_t new_bits_num;
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if ( b >> (8-1) == 0b0 )
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new_bits = b & 0b01111111,
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new_bits_num = 7,
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sequence_len = 1;
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else if ( b >> (8-2) == 0b10 )
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new_bits = b & 0b00111111,
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new_bits_num = 6,
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sequence_len = 2;
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else if ( b >> (8-3) == 0b110 )
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new_bits = b & 0b00011111,
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new_bits_num = 5,
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sequence_len = 3;
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else if ( b >> (8-4) == 0b1110 )
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new_bits = b & 0b00001111,
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new_bits_num = 4,
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sequence_len = 4;
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else if ( b >> (8-5) == 0b11110 )
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new_bits = b & 0b00000111,
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new_bits_num = 3,
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sequence_len = 5;
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else if ( b >> (8-6) == 0b111110 )
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new_bits = b & 0b00000011,
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new_bits_num = 2,
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sequence_len = 6;
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else if ( b >> (8-7) == 0b1111110 )
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new_bits = b & 0b00000001,
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new_bits_num = 1,
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sequence_len = 7;
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else
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return errno = EILSEQ, (size_t) -1;
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ret = ret >> new_bits_num | new_bits;
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}
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if ( !ret )
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{
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// TODO: Reset ps to initial state.
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return 0;
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}
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if ( (numbytes == 2 && ret <= 0x007F) ||
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(numbytes == 3 && ret <= 0x07FF) ||
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(numbytes == 4 && ret <= 0xFFFF) ||
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(numbytes == 5 && ret <= 0x1FFFFF) ||
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(numbytes == 6 && ret <= 0x3FFFFFF) )
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return errno = EILSEQ, (size_t) -1;
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if ( pwc )
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*pwc = ret;
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return numbytes;
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}
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