mirror of https://codeberg.org/grunfink/snac2.git
325 lines
7.6 KiB
C
325 lines
7.6 KiB
C
/* copyright (c) 2022 - 2024 grunfink et al. / MIT license */
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#ifndef _XS_UNICODE_H
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#define _XS_UNICODE_H
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int _xs_utf8_enc(char buf[4], unsigned int cpoint);
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int xs_is_utf8_cont_byte(char c);
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unsigned int xs_utf8_dec(char **str);
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int xs_unicode_width(unsigned int cpoint);
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int xs_is_surrogate(unsigned int cpoint);
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unsigned int xs_surrogate_dec(unsigned int p1, unsigned int p2);
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unsigned int xs_surrogate_enc(unsigned int cpoint);
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unsigned int *_xs_unicode_upper_search(unsigned int cpoint);
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unsigned int *_xs_unicode_lower_search(unsigned int cpoint);
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#define xs_unicode_is_upper(cpoint) (!!_xs_unicode_upper_search(cpoint))
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#define xs_unicode_is_lower(cpoint) (!!_xs_unicode_lower_search(cpoint))
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unsigned int xs_unicode_to_upper(unsigned int cpoint);
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unsigned int xs_unicode_to_lower(unsigned int cpoint);
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int xs_unicode_nfd(unsigned int cpoint, unsigned int *base, unsigned int *diac);
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int xs_unicode_nfc(unsigned int base, unsigned int diac, unsigned int *cpoint);
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int xs_unicode_is_alpha(unsigned int cpoint);
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#ifdef _XS_H
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xs_str *xs_utf8_enc(xs_str *str, unsigned int cpoint);
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#endif
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#ifdef XS_IMPLEMENTATION
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#ifndef xs_countof
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#define xs_countof(a) (sizeof((a)) / sizeof((*a)))
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#endif
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int _xs_utf8_enc(char buf[4], unsigned int cpoint)
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/* encodes an Unicode codepoint to utf-8 into buf and returns the size in bytes */
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{
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char *p = buf;
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if (cpoint < 0x80) /* 1 byte char */
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*p++ = cpoint & 0xff;
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else {
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if (cpoint < 0x800) /* 2 byte char */
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*p++ = 0xc0 | (cpoint >> 6);
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else {
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if (cpoint < 0x10000) /* 3 byte char */
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*p++ = 0xe0 | (cpoint >> 12);
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else { /* 4 byte char */
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*p++ = 0xf0 | (cpoint >> 18);
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*p++ = 0x80 | ((cpoint >> 12) & 0x3f);
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}
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*p++ = 0x80 | ((cpoint >> 6) & 0x3f);
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}
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*p++ = 0x80 | (cpoint & 0x3f);
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}
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return p - buf;
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}
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int xs_is_utf8_cont_byte(char c)
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/* returns true if c is an utf8 continuation byte */
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{
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return ((c & 0xc0) == 0x80);
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}
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unsigned int xs_utf8_dec(char **str)
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/* decodes an utf-8 char inside str and updates the pointer */
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{
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char *p = *str;
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unsigned int cpoint = 0;
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unsigned char c = *p++;
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int cb = 0;
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if ((c & 0x80) == 0) { /* 1 byte char */
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cpoint = c;
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}
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else
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if ((c & 0xe0) == 0xc0) { /* 2 byte char */
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cpoint = (c & 0x1f) << 6;
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cb = 1;
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}
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else
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if ((c & 0xf0) == 0xe0) { /* 3 byte char */
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cpoint = (c & 0x0f) << 12;
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cb = 2;
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}
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else
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if ((c & 0xf8) == 0xf0) { /* 4 byte char */
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cpoint = (c & 0x07) << 18;
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cb = 3;
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}
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/* process the continuation bytes */
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while (cb > 0 && *p && xs_is_utf8_cont_byte(*p))
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cpoint |= (*p++ & 0x3f) << (--cb * 6);
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/* incomplete or broken? */
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if (cb)
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cpoint = 0xfffd;
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*str = p;
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return cpoint;
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}
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/** Unicode character width: intentionally dead simple **/
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static unsigned int xs_unicode_width_table[] = {
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0x300, 0x36f, 0, /* diacritics */
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0x1100, 0x11ff, 2, /* Hangul */
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0x2e80, 0xa4cf, 2, /* CJK */
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0xac00, 0xd7a3, 2, /* more Hangul */
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0xe000, 0xf8ff, 0, /* private use */
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0xf900, 0xfaff, 2, /* CJK compatibility */
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0xff00, 0xff60, 2, /* full width things */
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0xffdf, 0xffe6, 2, /* full width things */
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0x1f200, 0x1ffff, 2, /* emojis */
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0x20000, 0x2fffd, 2 /* more CJK */
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};
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int xs_unicode_width(unsigned int cpoint)
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/* returns the width in columns of a Unicode codepoint (somewhat simplified) */
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{
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int b = 0;
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int t = xs_countof(xs_unicode_width_table) / 3 - 1;
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while (t >= b) {
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int n = (b + t) / 2;
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unsigned int *p = &xs_unicode_width_table[n * 3];
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if (cpoint < p[0])
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t = n - 1;
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else
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if (cpoint > p[1])
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b = n + 1;
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else
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return p[2];
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}
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return 1;
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}
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/** surrogate pairs **/
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int xs_is_surrogate(unsigned int cpoint)
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/* checks if cpoint is the first element of a Unicode surrogate pair */
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{
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return cpoint >= 0xd800 && cpoint <= 0xdfff;
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}
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unsigned int xs_surrogate_dec(unsigned int p1, unsigned int p2)
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/* "decodes" a surrogate pair into a codepoint */
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{
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return 0x10000 | ((p1 & 0x3ff) << 10) | (p2 & 0x3ff);
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}
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unsigned int xs_surrogate_enc(unsigned int cpoint)
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/* "encodes" a Unicode into a surrogate pair (p1 in the MSB word) */
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{
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unsigned int p1 = 0xd7c0 + (cpoint >> 10);
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unsigned int p2 = 0xdc00 + (cpoint & 0x3ff);
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return (p1 << 16) | p2;
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}
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#ifdef _XS_H
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xs_str *xs_utf8_enc(xs_str *str, unsigned int cpoint)
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/* encodes an Unicode codepoint to utf-8 into str */
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{
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char tmp[4];
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int c = _xs_utf8_enc(tmp, cpoint);
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return xs_append_m(str, tmp, c);
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}
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#endif /* _XS_H */
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#ifdef _XS_UNICODE_TBL_H
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/* include xs_unicode_tbl.h before this one to use these functions */
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unsigned int *_xs_unicode_upper_search(unsigned int cpoint)
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/* searches for an uppercase codepoint in the case fold table */
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{
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int b = 0;
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int t = xs_countof(xs_unicode_case_fold_table) / 2 + 1;
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while (t >= b) {
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int n = (b + t) / 2;
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unsigned int *p = &xs_unicode_case_fold_table[n * 2];
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if (cpoint < p[0])
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t = n - 1;
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else
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if (cpoint > p[0])
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b = n + 1;
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else
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return p;
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}
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return NULL;
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}
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unsigned int *_xs_unicode_lower_search(unsigned int cpoint)
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/* searches for a lowercase codepoint in the case fold table */
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{
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unsigned int *p = xs_unicode_case_fold_table;
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unsigned int *e = p + xs_countof(xs_unicode_case_fold_table);
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while (p < e) {
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if (cpoint == p[1])
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return p;
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p += 2;
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}
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return NULL;
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}
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unsigned int xs_unicode_to_lower(unsigned int cpoint)
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/* returns the cpoint to lowercase */
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{
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unsigned int *p = _xs_unicode_upper_search(cpoint);
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return p == NULL ? cpoint : p[1];
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}
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unsigned int xs_unicode_to_upper(unsigned int cpoint)
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/* returns the cpoint to uppercase */
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{
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unsigned int *p = _xs_unicode_lower_search(cpoint);
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return p == NULL ? cpoint : p[0];
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}
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int xs_unicode_nfd(unsigned int cpoint, unsigned int *base, unsigned int *diac)
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/* applies unicode Normalization Form D */
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{
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int b = 0;
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int t = xs_countof(xs_unicode_nfd_table) / 3 - 1;
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while (t >= b) {
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int n = (b + t) / 2;
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unsigned int *p = &xs_unicode_nfd_table[n * 3];
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int c = cpoint - p[0];
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if (c < 0)
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t = n - 1;
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else
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if (c > 0)
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b = n + 1;
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else {
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*base = p[1];
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*diac = p[2];
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return 1;
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}
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}
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return 0;
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}
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int xs_unicode_nfc(unsigned int base, unsigned int diac, unsigned int *cpoint)
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/* applies unicode Normalization Form C */
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{
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unsigned int *p = xs_unicode_nfd_table;
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unsigned int *e = p + xs_countof(xs_unicode_nfd_table);
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while (p < e) {
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if (p[1] == base && p[2] == diac) {
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*cpoint = p[0];
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return 1;
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}
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p += 3;
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}
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return 0;
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}
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int xs_unicode_is_alpha(unsigned int cpoint)
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/* checks if a codepoint is an alpha (i.e. a letter) */
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{
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int b = 0;
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int t = xs_countof(xs_unicode_alpha_table) / 2 - 1;
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while (t >= b) {
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int n = (b + t) / 2;
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unsigned int *p = &xs_unicode_alpha_table[n * 2];
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if (cpoint < p[0])
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t = n - 1;
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else
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if (cpoint > p[1])
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b = n + 1;
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else
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return 1;
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}
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return 0;
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}
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#endif /* _XS_UNICODE_TBL_H */
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#endif /* XS_IMPLEMENTATION */
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#endif /* _XS_UNICODE_H */
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