summaryrefslogtreecommitdiff
path: root/Source/cm_utf8.c
diff options
context:
space:
mode:
Diffstat (limited to 'Source/cm_utf8.c')
-rw-r--r--Source/cm_utf8.c84
1 files changed, 84 insertions, 0 deletions
diff --git a/Source/cm_utf8.c b/Source/cm_utf8.c
new file mode 100644
index 000000000..c9bf259ac
--- /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;
+ }
+}