snac2/xs_unicode.h
2023-08-03 08:42:38 +02:00

203 lines
4.9 KiB
C

/* copyright (c) 2022 - 2023 grunfink et al. / MIT license */
#ifndef _XS_UNICODE_H
#define _XS_UNICODE_H
xs_str *xs_utf8_enc(xs_str *str, unsigned int cpoint);
unsigned int xs_utf8_dec(char **str);
unsigned int *_xs_unicode_upper_search(unsigned int cpoint);
unsigned int *_xs_unicode_lower_search(unsigned int cpoint);
#define xs_unicode_is_upper(cpoint) (!!_xs_unicode_upper_search(cpoint))
#define xs_unicode_is_lower(cpoint) (!!_xs_unicode_lower_search(cpoint))
unsigned int xs_unicode_to_upper(unsigned int cpoint);
unsigned int xs_unicode_to_lower(unsigned int cpoint);
int xs_unicode_nfd(unsigned int cpoint, unsigned int *base, unsigned int *diac);
int xs_unicode_nfc(unsigned int base, unsigned int diac, unsigned int *cpoint);
#ifdef XS_IMPLEMENTATION
char *_xs_utf8_enc(char buf[4], unsigned int cpoint)
/* encodes an Unicode codepoint to utf-8 into buf and returns the new position */
{
unsigned char *p = (unsigned char *)buf;
if (cpoint < 0x80) /* 1 byte char */
*p++ = cpoint & 0xff;
else {
if (cpoint < 0x800) /* 2 byte char */
*p++ = 0xc0 | (cpoint >> 6);
else {
if (cpoint < 0x10000) /* 3 byte char */
*p++ = 0xe0 | (cpoint >> 12);
else { /* 4 byte char */
*p++ = 0xf0 | (cpoint >> 18);
*p++ = 0x80 | ((cpoint >> 12) & 0x3f);
}
*p++ = 0x80 | ((cpoint >> 6) & 0x3f);
}
*p++ = 0x80 | (cpoint & 0x3f);
}
return (char *)p;
}
xs_str *xs_utf8_enc(xs_str *str, unsigned int cpoint)
/* encodes an Unicode codepoint to utf-8 into str */
{
char tmp[4], *p;
p = _xs_utf8_enc(tmp, cpoint);
return xs_append_m(str, tmp, p - tmp);
}
unsigned int xs_utf8_dec(char **str)
/* decodes an utf-8 char inside str and updates the pointer */
{
unsigned char *p = (unsigned char *)*str;
unsigned int cpoint = 0;
int c = *p++;
int cb = 0;
if ((c & 0x80) == 0) { /* 1 byte char */
cpoint = c;
}
else
if ((c & 0xe0) == 0xc0) { /* 2 byte char */
cpoint = (c & 0x1f) << 6;
cb = 1;
}
else
if ((c & 0xf0) == 0xe0) { /* 3 byte char */
cpoint = (c & 0x0f) << 12;
cb = 2;
}
else
if ((c & 0xf8) == 0xf0) { /* 4 byte char */
cpoint = (c & 0x07) << 18;
cb = 3;
}
/* process the continuation bytes */
while (cb--) {
if ((*p & 0xc0) == 0x80)
cpoint |= (*p++ & 0x3f) << (cb * 6);
else {
cpoint = 0xfffd;
break;
}
}
*str = (char *)p;
return cpoint;
}
#ifdef _XS_UNICODE_TBL_H
/* include xs_unicode_tbl.h before to use these functions */
static int int_cmp(const void *p1, const void *p2)
{
const unsigned int *a = p1;
const unsigned int *b = p2;
return *a < *b ? -1 : *a > *b ? 1 : 0;
}
unsigned int *_xs_unicode_upper_search(unsigned int cpoint)
/* searches for an uppercase codepoint in the case fold table */
{
return bsearch(&cpoint, xs_unicode_case_fold_table,
sizeof(xs_unicode_case_fold_table) / (sizeof(unsigned int) * 2),
sizeof(unsigned int) * 2,
int_cmp);
}
unsigned int *_xs_unicode_lower_search(unsigned int cpoint)
/* searches for a lowercase codepoint in the case fold table */
{
unsigned int *p = xs_unicode_case_fold_table + 1;
unsigned int *e = xs_unicode_case_fold_table +
sizeof(xs_unicode_case_fold_table) / sizeof(unsigned int);
while (p < e) {
if (cpoint == *p)
return p;
p += 2;
}
return NULL;
}
unsigned int xs_unicode_to_upper(unsigned int cpoint)
/* returns the cpoint to uppercase */
{
unsigned int *p = _xs_unicode_lower_search(cpoint);
return p == NULL ? cpoint : p[-1];
}
unsigned int xs_unicode_to_lower(unsigned int cpoint)
/* returns the cpoint to lowercase */
{
unsigned int *p = _xs_unicode_upper_search(cpoint);
return p == NULL ? cpoint : p[1];
}
int xs_unicode_nfd(unsigned int cpoint, unsigned int *base, unsigned int *diac)
/* applies unicode Normalization Form D */
{
unsigned int *r = bsearch(&cpoint, xs_unicode_nfd_table,
sizeof(xs_unicode_nfd_table) / (sizeof(unsigned int) * 3),
sizeof(unsigned int) * 3,
int_cmp);
if (r != NULL) {
*base = r[1];
*diac = r[2];
}
return !!r;
}
int xs_unicode_nfc(unsigned int base, unsigned int diac, unsigned int *cpoint)
/* applies unicode Normalization Form C */
{
unsigned int *p = xs_unicode_nfd_table;
unsigned int *e = xs_unicode_nfd_table +
sizeof(xs_unicode_nfd_table) / sizeof(unsigned int);
while (p < e) {
if (p[1] == base && p[2] == diac) {
*cpoint = p[0];
return 1;
}
p += 3;
}
return 0;
}
#endif /* _XS_UNICODE_TBL_H */
#endif /* XS_IMPLEMENTATION */
#endif /* _XS_UNICODE_H */