169 lines
5.5 KiB
C
169 lines
5.5 KiB
C
#ifndef NU_UTF8_INTERNAL_H
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#define NU_UTF8_INTERNAL_H
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#include <sys/types.h>
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static inline
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unsigned utf8_char_length(const char c) {
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const unsigned char uc = c;
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if ((uc & 0x80) == 0) return 1;
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if ((uc & 0xE0) == 0xC0) return 2;
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if ((uc & 0xF0) == 0xE0) return 3;
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if ((uc & 0xF8) == 0xF0) return 4;
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return 0; /* undefined */
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}
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static inline
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void utf8_2b(const char *p, uint32_t *codepoint) {
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const unsigned char *up = (const unsigned char *)(p);
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/* UTF-8: 110xxxxx 10xxxxxx
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* |__ 1st unicode octet
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* 110xxx00 << 6 -> 00000xxx 00000000 |
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* --------
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* 110000xx << 6 -> 00000xxx xx000000 |__ 2nd unicode octet
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* 10xxxxxx -> 00000xxx xxxxxxxx |
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* -------- */
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*codepoint = (*(up) & 0x1C) << 6
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| ((*(up) & 0x03) << 6 | (*(up + 1) & 0x3F));
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}
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static inline
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void utf8_3b(const char *p, uint32_t *codepoint) {
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const unsigned char *up = (const unsigned char *)(p);
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/* UTF-8: 1110xxxx 10xxxxxx 10xxxxxx
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*
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* 1110xxxx << 12 -> xxxx0000 0000000 |__ 1st unicode octet
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* 10xxxx00 << 6 -> xxxxxxxx 0000000 |
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* --------
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* 100000xx << 6 -> xxxxxxxx xx00000 |__ 2nd unicode octet
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* 10xxxxxx -> xxxxxxxx xxxxxxx |
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* ------- */
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*codepoint =
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((*(up) & 0x0F) << 12 | (*(up + 1) & 0x3C) << 6)
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| ((*(up + 1) & 0x03) << 6 | (*(up + 2) & 0x3F));
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}
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static inline
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void utf8_4b(const char *p, uint32_t *codepoint) {
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const unsigned char *up = (const unsigned char *)(p);
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/* UTF-8: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
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*
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* 11110xxx << 18 -> 00xxx00 00000000 00000000 |__ 1st unicode octet
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* 10xx0000 << 12 -> 00xxxxx 00000000 00000000 |
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* -------
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* 1000xxxx << 12 -> 00xxxxx xxxx0000 00000000 |__ 2nd unicode octet
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* 10xxxx00 << 6 -> 00xxxxx xxxxxxxx 00000000 |
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* --------
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* 100000xx << 6 -> 00xxxxx xxxxxxxx xx000000 |__ 3rd unicode octet
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* 10xxxxxx -> 00xxxxx xxxxxxxx xxxxxxxx |
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* --------- */
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*codepoint =
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((*(up) & 0x07) << 18 | (*(up + 1) & 0x30) << 12)
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| ((*(up + 1) & 0x0F) << 12 | (*(up + 2) & 0x3C) << 6)
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| ((*(up + 2) & 0x03) << 6 | (*(up + 3) & 0x3F));
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}
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static inline
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unsigned utf8_codepoint_length(uint32_t codepoint) {
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if (codepoint < 128) return 1;
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if (codepoint < 0x0800) return 2;
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if (codepoint < 0x10000) return 3;
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return 4; /* de facto max length in UTF-8 */
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}
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static inline
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void b2_utf8(uint32_t codepoint, char *p) {
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unsigned char *up = (unsigned char *)(p);
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/* UNICODE: 00000xxx xxxxxxxx
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*
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* 00000xxx >> 6 -> 110xxx00 10000000 |__ 1st UTF-8 octet
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* xxxxxxxx >> 6 -> 110xxxxx 10000000 |
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* --------
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* |__ 2nd UTF-8 octet
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* xxxxxxxx -> 110xxxxx 10xxxxxx |
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* -------- */
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*(up) = (0xC0 | (codepoint & 0xFF00) >> 6 | (codepoint & 0xFF) >> 6);
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*(up + 1) = (0x80 | (codepoint & 0x3F));
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}
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static inline
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void b3_utf8(uint32_t codepoint, char *p) {
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unsigned char *up = (unsigned char *)(p);
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/* UNICODE: xxxxxxxx xxxxxxxx
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* |__ 1st UTF-8 octet
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* xxxxxxxx >> 12 -> 1110xxxx 10000000 10000000 |
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* --------
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* xxxxxxxx >> 6 -> 1110xxxx 10xxxx00 10000000 |__ 2nd UTF-8 octet
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* xxxxxxxx >> 6 -> 1110xxxx 10xxxxxx 10000000 |
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* --------
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* |__ 3rd UTF-8 octet
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* xxxxxxxx -> 1110xxxx 10xxxxxx 10xxxxxx |
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* -------- */
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*(up) = (0xE0 | (codepoint & 0xF000) >> 12);
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*(up + 1) = (0x80 | (codepoint & 0x0F00) >> 6 | (codepoint & 0xC0) >> 6);
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*(up + 2) = (0x80 | (codepoint & 0x3F));
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}
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static inline
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void b4_utf8(uint32_t codepoint, char *p) {
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unsigned char *up = (unsigned char *)(p);
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/* UNICODE: 000xxxxx xxxxxxxx xxxxxxxx
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* |__ 1st UTF-8 octet
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* 000xxxxx >> 18 -> 11110xxx 1000000 10000000 10000000 |
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* --------
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* 000xxxxx >> 12 -> 11110xxx 10xx000 10000000 10000000 |__ 2nd UTF-8 octet
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* xxxxxxxx >> 12 -> 11110xxx 10xxxxx 10000000 10000000 |
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* -------
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* xxxxxxxx >> 6 -> 11110xxx 10xxxxx 10xxxxx0 10000000 |__ 3rd UTF-8 octet
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* xxxxxxxx >> 6 -> 11110xxx 10xxxxx 10xxxxxx 10000000 |
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* --------
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* |__ 4th UTF-8 octet
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* xxxxxxxx -> 11110xxx 10xxxxx 10xxxxxx 10000000 | */
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*(up) = (0xF0 | ((codepoint & 0x1C0000) >> 18));
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*(up + 1) = (0x80 | (codepoint & 0x030000) >> 12 | (codepoint & 0x00E000) >> 12);
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*(up + 2) = (0x80 | (codepoint & 0x001F00) >> 6 | (codepoint & 0x0000E0) >> 6);
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*(up + 3) = (0x80 | (codepoint & 0x3F));
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}
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static inline
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int utf8_validread_basic(const char *p, size_t max_len) {
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const unsigned char *up = (const unsigned char *)(p);
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/* it should be 0xxxxxxx or 110xxxxx or 1110xxxx or 11110xxx
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* latter should be followed by number of 10xxxxxx */
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unsigned len = utf8_char_length(*p);
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/* codepoints longer than 6 bytes does not currently exist
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* and not currently supported
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* TODO: longer UTF-8 sequences support
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*/
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if (max_len < len) {
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return 0;
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}
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switch (len) {
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case 1: return 1; /* one byte codepoint */
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case 2: return ((*(up + 1) & 0xC0) == 0x80 ? 2 : 0);
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case 3: return ((*(up + 1) & 0xC0) == 0x80
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&& (*(up + 2) & 0xC0) == 0x80 ? 3 : 0);
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case 4: return ((*(up + 1) & 0xC0) == 0x80
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&& (*(up + 2) & 0xC0) == 0x80
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&& (*(up + 3) & 0xC0) == 0x80 ? 4 : 0);
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}
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return 0;
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}
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#endif /* NU_UTF8_INTERNAL_H */
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