102 lines
1.7 KiB
C
102 lines
1.7 KiB
C
#ifndef __MOREUTF8
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#define __MOREUTF8
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#include <stdio.h>
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static inline bool
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IsInsideGlyph(uchar ch)
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{
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return (ch & 0xC0) == 0x80;
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}
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static inline uint32
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UTF8NextCharLenUnsafe(const char *text)
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{
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const char *ptr = text;
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do {
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ptr++;
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} while (IsInsideGlyph(*ptr));
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return ptr - text;
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}
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static inline uint32
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UTF8NextCharLen(const char *text)
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{
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if (text == NULL || *text == 0)
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return 0;
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return UTF8NextCharLenUnsafe(text);
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}
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static inline uint32
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UTF8PreviousCharLen(const char *text, const char *limit)
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{
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const char *ptr = text;
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if (ptr == NULL || limit == NULL)
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return 0;
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do {
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if (ptr == limit)
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break;
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ptr--;
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} while (IsInsideGlyph(*ptr));
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return text - ptr;
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}
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// TODO: use this function in other places of this file...
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static inline uint32
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count_utf8_bytes(uchar ch)
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{
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// the number of high bits set until the first
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// unset bit determine the count of bytes used for
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// this glyph from this byte on
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uchar bit = 1 << 7;
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uint32 count = 1;
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if (ch & bit) {
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bit = bit >> 1;
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while (ch & bit) {
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count++;
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bit = bit >> 1;
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}
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}
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return count;
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}
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static inline uint32
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UTF8CountBytes(const char *text, uint32 numChars)
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{
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if (text) {
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// iterate over numChars glyphs incrementing ptr by the
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// number of bytes for each glyph, which is encoded in
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// the first byte of any glyph.
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const char *ptr = text;
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while (numChars--) {
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ptr += count_utf8_bytes(*ptr);
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}
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return ptr - text;
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}
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return 0;
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}
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static inline uint32
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UTF8CountChars(const char *text, int32 numBytes)
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{
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const char* ptr = text;
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const char* last = ptr + numBytes - 1;
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uint32 count = 0;
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while (ptr <= last) {
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ptr += UTF8NextCharLen(ptr);
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count++;
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}
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return count;
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}
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#endif
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