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