diff options
Diffstat (limited to 'libs/libc/inc/utf8.h')
| -rw-r--r-- | libs/libc/inc/utf8.h | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/libs/libc/inc/utf8.h b/libs/libc/inc/utf8.h new file mode 100644 index 0000000..c805157 --- /dev/null +++ b/libs/libc/inc/utf8.h @@ -0,0 +1,40 @@ +// MIT License, Copyright (c) 2021 Marvin Borner + +#ifndef UTF8_H +#define UTF8_H + +#include <def.h> + +static void *utf8_decode(void *buf, u32 *c, u32 *e) +{ + static const u8 lengths[] = { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 2, 2, 3, 3, 4, 0 }; + static const u8 masks[] = { 0x00, 0x7f, 0x1f, 0x0f, 0x07 }; + static const u32 mins[] = { 4194304, 0, 128, 2048, 65536 }; + static const u8 shiftc[] = { 0, 18, 12, 6, 0 }; + static const u8 shifte[] = { 0, 6, 4, 2, 0 }; + + u8 *s = buf; + u8 len = lengths[s[0] >> 3]; + + u8 *next = s + len + !len; + + *c = (u32)(s[0] & masks[len]) << 18; + *c |= (u32)(s[1] & 0x3f) << 12; + *c |= (u32)(s[2] & 0x3f) << 6; + *c |= (u32)(s[3] & 0x3f) << 0; + *c >>= shiftc[len]; + + *e = (*c < mins[len]) << 6; + *e |= ((*c >> 11) == 0x1b) << 7; + *e |= (*c > 0x10FFFF) << 8; + *e |= (s[1] & 0xc0) >> 2; + *e |= (s[2] & 0xc0) >> 4; + *e |= (s[3]) >> 6; + *e ^= 0x2a; + *e >>= shifte[len]; + + return next; +} + +#endif |