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Diffstat (limited to 'Source/cm_utf8.c')
-rw-r--r-- | Source/cm_utf8.c | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/Source/cm_utf8.c b/Source/cm_utf8.c new file mode 100644 index 0000000..c9bf259 --- /dev/null +++ b/Source/cm_utf8.c @@ -0,0 +1,84 @@ +/*============================================================================ + 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 = (unsigned char)*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]; + int left; + for(left = ones-1; left && first != last; --left) + { + c = (unsigned char)*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; + } +} |