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#ifndef UTF8_H_INCLUDED
#define UTF8_H_INCLUDED
/*
// Example:
#include <stc/cstr.h>
#include <stc/csview.h>
int main()
{
c_auto (cstr, s1) {
s1 = cstr_new("hell😀 w😀rld");
printf("%s\n", cstr_str(&s1));
cstr_replace_sv(&s1, utf8_substr(cstr_str(&s1), 7, 1), c_sv("🐨"));
printf("%s\n", cstr_str(&s1));
csview sv = csview_from_s(s1);
c_foreach (i, csview, sv)
printf("%" c_PRIsv ",", c_ARGsv(i.codep));
}
}
// Output:
// hell😀 w😀rld
// hell😀 w🐨rld
// h,e,l,l,😀, ,w,🐨,r,l,d,
*/
#include "ccommon.h"
#include <ctype.h>
/* number of codepoints in the utf8 string s, or SIZE_MAX if invalid utf8: */
enum { UTF8_OK = 0, UTF8_ERROR = 4 };
typedef struct { uint32_t state, codep, size; } utf8_decode_t;
/* decode next utf8 codepoint. */
STC_API size_t utf8_encode(char *out, uint32_t c);
STC_API uint32_t utf8_decode(utf8_decode_t *d, const uint8_t b);
STC_API const uint8_t* utf8_next(utf8_decode_t *d, const uint8_t* u);
STC_API size_t utf8_size(const char *s);
STC_API size_t utf8_size_n(const char *s, size_t n);
STC_API const char* utf8_at(const char *s, size_t index);
STC_INLINE size_t utf8_pos(const char* s, size_t index)
{ return utf8_at(s, index) - s; }
STC_INLINE bool utf8_valid(const char* s)
{ return utf8_size(s) != SIZE_MAX; }
STC_INLINE uint32_t utf8_peek(const char *s) {
utf8_decode_t d = {UTF8_OK, 0};
utf8_next(&d, (const uint8_t*)s);
return d.codep;
}
STC_INLINE size_t utf8_codep_size(const char *s) {
utf8_decode_t d = {UTF8_OK, 0};
utf8_next(&d, (const uint8_t*)s);
return d.size;
}
// --------------------------- IMPLEMENTATION ---------------------------------
#ifdef i_implement
// https://news.ycombinator.com/item?id=15423674
// https://gist.github.com/s4y/344a355f8c1f99c6a4cb2347ec4323cc
STC_DEF uint32_t utf8_decode(utf8_decode_t *d, const uint8_t b)
{
switch (d->state) {
case UTF8_OK:
if (b < 0x80) d->codep = b, d->size = 1;
else if (b < 0xC2) d->state = UTF8_ERROR, d->size = 0;
else if (b < 0xE0) d->state = 1, d->codep = b & 0x1F, d->size = 2;
else if (b < 0xF0) d->state = 2, d->codep = b & 0x0F, d->size = 3;
else if (b < 0xF5) d->state = 3, d->codep = b & 0x07, d->size = 4;
else d->state = UTF8_ERROR, d->size = 0;
break;
case 1: case 2: case 3:
if ((b & 0xC0) == 0x80) {
d->state -= 1;
d->codep = (d->codep << 6) | (b & 0x3F);
} else
d->state = UTF8_ERROR, d->size = 0;
}
return d->state;
}
STC_DEF size_t utf8_encode(char *out, uint32_t c)
{
char* p = out;
if (c < 0x80U) {
*p++ = (char) c;
} else if (c < 0x0800U) {
*p++ = (char) ((c>>6 & 0x1F) | 0xC0);
*p++ = (char) ((c & 0x3F) | 0x80);
} else if (c < 0x010000U) {
if (c < 0xD800U || c >= 0xE000U) {
*p++ = (char) ((c>>12 & 0x0F) | 0xE0);
*p++ = (char) ((c>>6 & 0x3F) | 0x80);
*p++ = (char) ((c & 0x3F) | 0x80);
}
} else if (c < 0x110000U) {
*p++ = (char) ((c>>18 & 0x07) | 0xF0);
*p++ = (char) ((c>>12 & 0x3F) | 0x80);
*p++ = (char) ((c>>6 & 0x3F) | 0x80);
*p++ = (char) ((c & 0x3F) | 0x80);
}
return p - out;
}
STC_DEF const uint8_t* utf8_next(utf8_decode_t *d, const uint8_t* u) {
utf8_decode(d, *u++);
switch (d->size) {
case 4: utf8_decode(d, *u++);
case 3: utf8_decode(d, *u++);
case 2: utf8_decode(d, *u++);
}
return u;
}
STC_DEF size_t utf8_size(const char *s)
{
utf8_decode_t d = {UTF8_OK, 0};
size_t size = 0;
while (*s)
size += !utf8_decode(&d, (uint8_t)*s++);
return d.state ? SIZE_MAX : size;
}
STC_DEF size_t utf8_size_n(const char *s, size_t n)
{
utf8_decode_t d = {UTF8_OK, 0};
size_t size = 0;
while ((n-- != 0) & (*s != 0))
size += !utf8_decode(&d, (uint8_t)*s++);
return !d.state ? size : SIZE_MAX;
}
STC_DEF const char* utf8_at(const char *s, size_t index)
{
utf8_decode_t d = {UTF8_OK, 0};
for (size_t i = 0; (i < index) & (*s != 0); ++s)
i += !utf8_decode(&d, (uint8_t)*s);
return s;
}
#endif
#endif
#undef i_opt
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