139 lines
4 KiB
C
139 lines
4 KiB
C
/*
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* Indic algorithms for QEmacs.
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*
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* Copyright (c) 2000 Fabrice Bellard.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include "cutils.h"
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#include "unicode_join.h"
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#define VIRAMA 0x94d
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#define RA 0x930
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#define RRA 0x931
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#define ZERO_WIDTH_JOINER 0x200d
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/* private unicode extensions */
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#define DEAD_CONSONANT_OFFSET 0x10000
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#define HALF_OFFSET 0xe000
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#define RA_SUP 0xe97e
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#define RA_SUB 0xe97f
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#define RRA_HALF 0xe97d
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#define RA_DEAD (RA + DEAD_CONSONANT_OFFSET)
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#if 0
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static int devanagari_is_vowel_sign(char32_t i) {
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return (i >= 0x93E && i <= 0x94c) || (i >= 0x962 && i <= 0x963);
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}
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#endif
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static int devanagari_is_consonant(char32_t i) {
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return (i >= 0x915 && i <= 0x939) || (i >= 0x958 && i <= 0x95f);
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}
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static int devanagari_is_vowel(char32_t i) {
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return (i >= 0x905 && i <= 0x914);
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}
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static int devanagari_is_dead_consonant(char32_t i) {
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return (i >= DEAD_CONSONANT_OFFSET && i <= DEAD_CONSONANT_OFFSET + 0x7f);
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}
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/* always returns a smaller buffer */
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int devanagari_log2vis(char32_t *str, unsigned int *ctog, int len) {
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char32_t cc, c;
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int i, len1, j, k;
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/* CG: C99 variable-length arrays may be too large */
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char32_t *q, buf[len];
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/* Rule 1: dead consonant rule */
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q = buf;
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len1 = len - 1;
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for (i = 0; i < len; i++) {
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cc = str[i];
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if (devanagari_is_consonant(cc) && i < len1 && str[i+1] == VIRAMA) {
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*q++ = cc + DEAD_CONSONANT_OFFSET;
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i++;
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} else {
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*q++ = cc;
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}
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}
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/************ RA rules */
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/* XXX: rule 3, 4, 7 should be handled as ligatures */
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for (i = 0; i < len1; i++) {
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/* Rule 2 */
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if (buf[i] == RA_DEAD &&
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(devanagari_is_vowel(buf[i+1]) || devanagari_is_consonant(buf[i+1]))) {
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buf[i] = buf[i+1];
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buf[i+1] = RA_SUP;
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} else
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/* Rule 5 */
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if (buf[i] == RRA &&
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buf[i+1] == VIRAMA) {
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buf[i] = RRA_HALF;
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buf[i+1] = 0;
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} else
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/* Rule 5a */
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if (buf[i] == RA_DEAD &&
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buf[i+1] == ZERO_WIDTH_JOINER) {
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buf[i] = RRA_HALF;
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buf[i+1] = 0;
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} else
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/* Rule 6 */
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if (devanagari_is_dead_consonant(buf[i]) && buf[i+1] == RA) {
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buf[i] -= DEAD_CONSONANT_OFFSET;
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buf[i+1] = RA_SUB;
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} else
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/* Rule 8 */
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if (devanagari_is_dead_consonant(buf[i]) &&
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buf[i+1] == RA_DEAD) {
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buf[i] -= DEAD_CONSONANT_OFFSET;
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buf[i+1] = RA_SUB;
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buf[i+2] = VIRAMA;
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}
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}
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/* convert dead consonant to half consonants */
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for (i = 0; i < len1; i++) {
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if (devanagari_is_dead_consonant(buf[i]) &&
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(i == (len1 - 1) ||
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buf[i+1] == ZERO_WIDTH_JOINER ||
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devanagari_is_consonant(buf[i+1]) ||
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devanagari_is_dead_consonant(buf[i+1]))) {
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buf[i] -= DEAD_CONSONANT_OFFSET + HALF_OFFSET;
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}
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}
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/* output result and update ctog */
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j = 0;
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for (i = 0; i < len; i++) {
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c = buf[i];
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if (c != 0) {
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ctog[i] = j;
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str[j++] = c;
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} else {
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/* zero: associate it to previous char */
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/* XXX: is it always a good guess ? */
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k = j - 1;
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if (k < 0)
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k = 0;
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ctog[i] = k;
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}
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}
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return j;
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}
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