mirror of https://github.com/swaywm/sway.git
102 lines
1.5 KiB
C
102 lines
1.5 KiB
C
#include <stdint.h>
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#include <stddef.h>
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#include "unicode.h"
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size_t utf8_chsize(uint32_t ch) {
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if (ch < 0x80) {
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return 1;
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} else if (ch < 0x800) {
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return 2;
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} else if (ch < 0x10000) {
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return 3;
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}
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return 4;
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}
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static const uint8_t masks[] = {
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0x7F,
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0x1F,
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0x0F,
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0x07,
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0x03,
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0x01
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};
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uint32_t utf8_decode(const char **char_str) {
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uint8_t **s = (uint8_t **)char_str;
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uint32_t cp = 0;
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if (**s < 128) {
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// shortcut
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cp = **s;
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++*s;
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return cp;
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}
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int size = utf8_size((char *)*s);
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if (size == -1) {
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++*s;
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return UTF8_INVALID;
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}
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uint8_t mask = masks[size - 1];
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cp = **s & mask;
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++*s;
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while (--size) {
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cp <<= 6;
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cp |= **s & 0x3f;
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++*s;
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}
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return cp;
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}
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size_t utf8_encode(char *str, uint32_t ch) {
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size_t len = 0;
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uint8_t first;
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if (ch < 0x80) {
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first = 0;
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len = 1;
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} else if (ch < 0x800) {
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first = 0xc0;
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len = 2;
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} else if (ch < 0x10000) {
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first = 0xe0;
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len = 3;
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} else {
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first = 0xf0;
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len = 4;
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}
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for (size_t i = len - 1; i > 0; --i) {
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str[i] = (ch & 0x3f) | 0x80;
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ch >>= 6;
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}
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str[0] = ch | first;
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return len;
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}
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static const struct {
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uint8_t mask;
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uint8_t result;
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int octets;
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} sizes[] = {
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{ 0x80, 0x00, 1 },
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{ 0xE0, 0xC0, 2 },
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{ 0xF0, 0xE0, 3 },
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{ 0xF8, 0xF0, 4 },
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{ 0xFC, 0xF8, 5 },
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{ 0xFE, 0xF8, 6 },
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{ 0x80, 0x80, -1 },
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};
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int utf8_size(const char *s) {
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uint8_t c = (uint8_t)*s;
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for (size_t i = 0; i < sizeof(sizes) / sizeof(*sizes); ++i) {
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if ((c & sizes[i].mask) == sizes[i].result) {
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return sizes[i].octets;
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}
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}
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return -1;
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}
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