318 lines
8.1 KiB
C
318 lines
8.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/* https://en.wikipedia.org/wiki/IAST */
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#include "compat.h"
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#include "transliteration.h"
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#include "utf8.h"
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#define SCHWA_CHARACTER 'a'
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#define ZERO_WIDTH_JOINER 0x200d
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#define VIRAMA 0x094d
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#define CHUNKSIZE 1024
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static struct translit_letter table[] = {
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/* Special characters */
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{0x0950, SPECIAL, "aum"}, /* aum */
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/* Vowels */
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{0x0910, VOWEL, "ai"}, /* 01 */
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{0x0914, VOWEL, "au"}, /* 02 */
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{0x0905, VOWEL, "a"}, /* 03 */
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{0x0906, VOWEL, "\u0101"}, /* 04 (aa) */
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{0x0907, VOWEL, "i"}, /* 05 */
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{0x0908, VOWEL, "\u012b"}, /* 06 (ii) */
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{0x0909, VOWEL, "u"}, /* 07 */
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{0x090a, VOWEL, "\u016b"}, /* 08 (uu) */
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{0x090b, VOWEL, "\u1e5b"}, /* 09 (.r) */
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{0x0960, VOWEL, "\u1e5d"}, /* 10 (.rr) */
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{0x090c, VOWEL, "\u1e37"}, /* 11 (.l) */
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{0x0961, VOWEL, "\u1e39"}, /* 12 (.ll) */
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{0x090f, VOWEL, "e"}, /* 13 */
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{0x0913, VOWEL, "o"}, /* 14 */
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/* Codas */
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{0x0902, CODA, "\u1e43"}, /* anusvara (.m) */
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{0x0903, CODA, "\u1e25"}, /* visarga (.h) */
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{0x093d, CODA, "'"}, /* avagrada (') */
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{0x0901, CODA, "m\u0310"}, /* candrabindu */
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/* Consonants */
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{0x0916, CONSONANT, "kh"}, /* 01 */
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{0x0918, CONSONANT, "gh"}, /* 02 */
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{0x091b, CONSONANT, "ch"}, /* 03 */
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{0x091d, CONSONANT, "jh"}, /* 04 */
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{0x0920, CONSONANT, "\u1e6dh"}, /* 05 (.th) */
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{0x0922, CONSONANT, "\u1e0dh"}, /* 06 (.dh) */
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{0x0925, CONSONANT, "th"}, /* 07 */
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{0x0927, CONSONANT, "dh"}, /* 08 */
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{0x092b, CONSONANT, "ph"}, /* 09 */
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{0x092d, CONSONANT, "bh"}, /* 10 */
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{0x0915, CONSONANT, "k"}, /* 11 */
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{0x0917, CONSONANT, "g"}, /* 12 */
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{0x0919, CONSONANT, "\u1e45"}, /* 13 ("n) */
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{0x0939, CONSONANT, "h"}, /* 14 */
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{0x091a, CONSONANT, "c"}, /* 15 */
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{0x091c, CONSONANT, "j"}, /* 16 */
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{0x091e, CONSONANT, "\u00f1"}, /* 17 (~n) */
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{0x092f, CONSONANT, "y"}, /* 18 */
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{0x0936, CONSONANT, "\u015b"}, /* 19 ("s) */
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{0x091f, CONSONANT, "\u1e6d"}, /* 20 (.t) */
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{0x0921, CONSONANT, "\u1e0d"}, /* 21 (.d) */
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{0x0923, CONSONANT, "\u1e47"}, /* 22 (.n) */
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{0x0930, CONSONANT, "r"}, /* 23 */
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{0x0937, CONSONANT, "\u1e63"}, /* 24 (.s) */
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{0x0924, CONSONANT, "t"}, /* 25 */
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{0x0926, CONSONANT, "d"}, /* 26 */
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{0x0928, CONSONANT, "n"}, /* 27 */
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{0x0932, CONSONANT, "l"}, /* 28 */
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{0x0938, CONSONANT, "s"}, /* 29 */
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{0x092a, CONSONANT, "p"}, /* 30 */
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{0x092c, CONSONANT, "b"}, /* 31 */
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{0x092e, CONSONANT, "m"}, /* 32 */
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{0x0935, CONSONANT, "v"}, /* 33 */
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{0x0933, CONSONANT, "\u1e37"}, /* (.l) */
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/* Numbers */
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{0x0966, NUMBER, "0"},
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{0x0967, NUMBER, "1"},
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{0x0968, NUMBER, "2"},
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{0x0969, NUMBER, "3"},
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{0x096a, NUMBER, "4"},
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{0x096b, NUMBER, "5"},
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{0x096c, NUMBER, "6"},
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{0x096d, NUMBER, "7"},
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{0x096e, NUMBER, "8"},
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{0x096f, NUMBER, "9"},
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/* Diacritic modifiers */
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{0x0948, VOWEL_SIGN, "ai"},
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{0x094c, VOWEL_SIGN, "au"},
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{0x093e, VOWEL_SIGN, "\u0101"}, /* (aa) */
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{0x093f, VOWEL_SIGN, "i"},
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{0x0940, VOWEL_SIGN, "\u012b"}, /* (ii) */
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{0x0941, VOWEL_SIGN, "u"},
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{0x0942, VOWEL_SIGN, "\u016b"}, /* (uu) */
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{0x0943, VOWEL_SIGN, "\u1e5b"}, /* (.r) */
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{0x0944, VOWEL_SIGN, "\u1e5d"}, /* (.rr) */
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{0x0962, VOWEL_SIGN, "\u1e37"}, /* (.l) */
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{0x0963, VOWEL_SIGN, "\u1e39"}, /* (.ll) */
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{0x0947, VOWEL_SIGN, "e"},
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{0x094b, VOWEL_SIGN, "o"},
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{0x094d, VOWEL_SIGN, ""}, /* virama */
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{0x0965, CODA, "||"}, /* double danda */
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{0x0964, CODA, "|"}, /* danda */
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};
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static struct translit_letter *letter_by_code(unsigned int c)
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{
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unsigned int i;
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for (i = 0; i < ARRAY_SIZE(table); i++) {
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if (table[i].code == c) {
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return table + i;
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}
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}
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return NULL;
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}
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static inline int is_vowel_sign(unsigned int c)
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{
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struct translit_letter *letter = letter_by_code(c);
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return letter && letter->type == VOWEL_SIGN;
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}
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int transliterate_devanagari_to_latin(const char *devanagari, char **ret)
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{
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struct translit_letter *letter, *prev = NULL;
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unsigned int c, alloc = 0, done = 0, len;
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const char *src = devanagari;
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char *latin = NULL;
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while (1) {
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if (alloc < done + UNICODE_MAX_LENGTH) {
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latin = realloc(latin, alloc + CHUNKSIZE);
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alloc += CHUNKSIZE;
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}
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c = utf8_unpack_char(src);
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len = utf8_char_length(c);
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src += len;
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letter = letter_by_code(c);
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if (letter) {
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switch (letter->type) {
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case CONSONANT:
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strcpy(latin + done, letter->data);
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done += strlen(letter->data);
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*(latin + done++) = SCHWA_CHARACTER;
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break;
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case VOWEL_SIGN:
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if (done && *(latin + done - 1) == 'a') {
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/* delete the inherent schwa */
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done--;
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}
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default:
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if (letter->type == VOWEL && prev) {
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utf8_pack_char(latin + done, 0x200c);
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done += 3;
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}
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strcpy(latin + done, letter->data);
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done += strlen(letter->data);
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break;
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}
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} else {
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if (c == ZERO_WIDTH_JOINER && done) {
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/* The ZWJ can substitute a virama so we need
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* to remove the inherent schwa. */
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if (is_vowel_sign(utf8_unpack_char(src))) {
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done--;
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}
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}
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utf8_pack_char(latin + done, c);
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done += len;
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}
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if (c == 0)
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break;
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prev = letter;
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}
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*ret = latin;
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return 0;
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}
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static struct translit_letter *letter_by_data(const char *data)
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{
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unsigned int i, len;
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for (i = 0; i < ARRAY_SIZE(table); i++) {
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len = strlen(table[i].data);
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if (len && strncmp(table[i].data, data, len) == 0) {
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return table + i;
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}
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}
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return NULL;
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}
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static struct translit_letter *vowel_sign_by_data(const char *data)
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{
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unsigned int i, len;
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for (i = 0; i < ARRAY_SIZE(table); i++) {
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len = strlen(table[i].data);
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if (len && strncmp(table[i].data, data, len) == 0 &&
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table[i].type == VOWEL_SIGN) {
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return table + i;
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}
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}
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return NULL;
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}
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#define PACK_LETTER(d, c) { \
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utf8_pack_char(d, c); \
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done += utf8_char_length(c); \
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}
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int transliterate_latin_to_devanagari(const char *latin, char **ret)
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{
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struct translit_letter *letter = NULL, *next, *last = NULL;
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unsigned int alloc = 0, done = 0, c = 0;
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const char *src = latin;
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char *devanagari = NULL;
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while (*src) {
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if (alloc < done + UNICODE_MAX_LENGTH) {
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devanagari = realloc(devanagari, alloc + CHUNKSIZE);
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alloc += CHUNKSIZE;
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}
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/* zero-width non-joiner */
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if (strncmp(src, "\u200c", 3) == 0) {
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if (last) {
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/* not at the beginning of a word */
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next = letter_by_data(src + 3);
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if (next && next->type == CONSONANT) {
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PACK_LETTER(devanagari + done, 0x200c);
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}
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}
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src += 3;
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continue;
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}
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letter = letter_by_data(src);
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if (letter) {
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if (letter->code == 0x090c) { /* independent ‘.l’ vowel */
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next = letter_by_data(src + 3);
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if (last || (next && next->type == VOWEL && next->code != 0x090c)) {
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letter = letter_by_code(0x0933); /* .la */
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}
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}
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encode_consonant:
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/* A consonant or an initial vowel */
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utf8_pack_char(devanagari + done, letter->code);
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PACK_LETTER(devanagari + done, letter->code);
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src += strlen(letter->data);
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c = utf8_unpack_char(src);
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if (c == ZERO_WIDTH_JOINER)
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src += 3;
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last = letter;
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if (letter->type == VOWEL || letter->type == CODA)
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continue;
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/* A vowel modifier (if any) */
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letter = vowel_sign_by_data(src);
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if (letter) {
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if (letter->code == 0x0962) {
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next = letter_by_data(src + 3);
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if (next && next->type == VOWEL) {
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/* consonant ‘.la’ */
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letter = letter_by_code(0x0933);
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if (last && last->type == CONSONANT)
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PACK_LETTER(devanagari + done, VIRAMA);
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goto encode_consonant;
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}
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}
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if (c == ZERO_WIDTH_JOINER)
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PACK_LETTER(devanagari + done, c);
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PACK_LETTER(devanagari + done, letter->code);
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src += strlen(letter->data);
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} else if (*src == SCHWA_CHARACTER) {
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src++;
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} else {
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if (last->type == CONSONANT) {
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PACK_LETTER(devanagari + done, VIRAMA);
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}
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}
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} else {
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c = utf8_unpack_char(src);
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PACK_LETTER(devanagari + done, c);
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src += utf8_char_length(c);
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last = NULL;
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}
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}
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if (devanagari)
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devanagari[done] = '\0';
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*ret = devanagari;
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return 0;
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}
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