85 lines
2.7 KiB
C
85 lines
2.7 KiB
C
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/*============================================================================
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CMake - Cross Platform Makefile Generator
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Copyright 2000-2009 Kitware, Inc., Insight Software Consortium
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Distributed under the OSI-approved BSD License (the "License");
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see accompanying file Copyright.txt for details.
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This software is distributed WITHOUT ANY WARRANTY; without even the
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implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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See the License for more information.
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============================================================================*/
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#include "cm_utf8.h"
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/*
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RFC 3629
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07-bit: 0xxxxxxx
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11-bit: 110xxxxx 10xxxxxx
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16-bit: 1110xxxx 10xxxxxx 10xxxxxx
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21-bit: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
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Pre-RFC Compatibility
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26-bit: 111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
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31-bit: 1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
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*/
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/* Number of leading ones before a zero in the byte. */
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static unsigned char const cm_utf8_ones[256] = {
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
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3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,5,5,5,5,6,6,7,8
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};
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/* Mask away control bits from bytes with n leading ones. */
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static unsigned char const cm_utf8_mask[7] = {
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0xEF, 0x3F, 0x1F, 0x0F, 0x07, 0x03, 0x01
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};
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/* Minimum allowed value when first byte has n leading ones. */
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static unsigned int const cm_utf8_min[7] = {
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0, 0, 1u<<7, 1u<<11, 1u<<16, 1u<<21, 1u<<26 /*, 1u<<31 */
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};
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/*--------------------------------------------------------------------------*/
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const char* cm_utf8_decode_character(const char* first, const char* last,
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unsigned int* pc)
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{
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/* Count leading ones in the first byte. */
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unsigned char c = *first++;
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unsigned char const ones = cm_utf8_ones[c];
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switch(ones)
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{
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case 0: *pc = c; return first; /* One-byte character. */
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case 1: case 7: case 8: return 0; /* Invalid leading byte. */
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default: break;
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}
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/* Extract bits from this multi-byte character. */
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{
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unsigned int uc = c & cm_utf8_mask[ones];
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unsigned char left;
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for(left = ones-1; left && first != last; --left)
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{
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c = *first++;
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if(cm_utf8_ones[c] != 1)
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{
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return 0;
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}
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uc = (uc << 6) | (c & cm_utf8_mask[1]);
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}
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if(left > 0 || uc < cm_utf8_min[ones])
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{
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return 0;
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}
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*pc = uc;
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return first;
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}
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}
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