139 lines
4.3 KiB
C
139 lines
4.3 KiB
C
/*
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* Copyright (C) 1999-2001, 2007 Free Software Foundation, Inc.
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* This file is part of the GNU LIBICONV Library.
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*
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* The GNU LIBICONV Library is free software; you can redistribute it
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* and/or modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* The GNU LIBICONV Library is distributed in the hope that it will be
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* useful, 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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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with the GNU LIBICONV Library; see the file COPYING.LIB.
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* If not, write to the Free Software Foundation, Inc., 51 Franklin Street,
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* Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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/*
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* JOHAB
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*/
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/*
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Conversion between JOHAB codes (s1,s2) and KSX1001 codes (c1,c2):
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Example. (s1,s2) = 0xD931, (c1,c2) = 0x2121.
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(s1,s2) = 0xDEF1, (c1,c2) = 0x2C71.
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(s1,s2) = 0xE031, (c1,c2) = 0x4A21.
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(s1,s2) = 0xF9FE, (c1,c2) = 0x7D7E.
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0xD9 <= s1 <= 0xDE || 0xE0 <= s1 <= 0xF9,
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0x31 <= s2 <= 0x7E || 0x91 <= s2 <= 0xFE,
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0x21 <= c1 <= 0x2C || 0x4A <= c1 <= 0x7D,
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0x21 <= c2 <= 0x7E.
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Invariant:
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94*(s1 < 0xE0 ? 2*s1-0x1B2 : 2*s1-0x197) + (s2 < 0x91 ? s2-0x31 : s2-0x43)
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= 94*(c1-0x21)+(c2-0x21)
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Conversion (s1,s2) -> (c1,c2):
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t1 := (s1 < 0xE0 ? 2*s1-0x1B2 : 2*s1-0x197)
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t2 := (s2 < 0x91 ? s2-0x31 : s2-0x43)
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c1 := t1 + (t2 < 0x5E ? 0 : 1) + 0x21
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c2 := (t2 < 0x5E ? t2 : t2-0x5E) + 0x21
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Conversion (c1,c2) -> (s1,s2):
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t := (c1 < 0x4A ? (c1-0x21+0x1B2) : (c1-0x21+0x197))
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s1 := t >> 1
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t2 := (t & 1) * 0x5E + (c2 - 0x21)
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s2 := (t2 < 0x4E ? t2+0x31 : t2+0x43)
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*/
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static int
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johab_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, int n)
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{
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unsigned char c = *s;
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if (c < 0x80) {
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if (c == 0x5c)
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*pwc = (ucs4_t) 0x20a9;
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else
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*pwc = (ucs4_t) c;
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return 1;
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} else if (c < 0xd8) {
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return johab_hangul_mbtowc(conv,pwc,s,n);
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} else {
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unsigned char s1, s2;
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s1 = c;
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if ((s1 >= 0xd9 && s1 <= 0xde) || (s1 >= 0xe0 && s1 <= 0xf9)) {
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if (n < 2)
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return RET_TOOFEW(0);
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s2 = s[1];
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if ((s2 >= 0x31 && s2 <= 0x7e) || (s2 >= 0x91 && s2 <= 0xfe)) {
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/* In KSC 5601, now KS X 1001, the region s1 = 0xDA, 0xA1 <= s2 <= 0xD3
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contains the 51 Jamo (Hangul letters). But in the Johab encoding,
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they have been moved to the Hangul section, see
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johab_hangul_page31. */
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if (!(s1 == 0xda && (s2 >= 0xa1 && s2 <= 0xd3))) {
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unsigned char t1 = (s1 < 0xe0 ? 2*(s1-0xd9) : 2*s1-0x197);
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unsigned char t2 = (s2 < 0x91 ? s2-0x31 : s2-0x43);
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unsigned char buf[2];
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buf[0] = t1 + (t2 < 0x5e ? 0 : 1) + 0x21;
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buf[1] = (t2 < 0x5e ? t2 : t2-0x5e) + 0x21;
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return ksc5601_mbtowc(conv,pwc,buf,2);
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}
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}
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}
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return RET_ILSEQ;
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}
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}
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static int
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johab_wctomb (conv_t conv, unsigned char *r, ucs4_t wc, int n)
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{
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unsigned char buf[2];
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int ret;
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/* Try ASCII variation. */
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if (wc < 0x0080 && wc != 0x005c) {
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*r = wc;
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return 1;
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}
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if (wc == 0x20a9) {
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*r = 0x5c;
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return 1;
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}
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/* Try JOHAB Hangul table before KSC5601 table, because the KSC5601 table
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contains some (2350 out of 11172) Hangul syllables (rows 0x30XX..0x48XX),
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and we want the search to return the JOHAB Hangul table entry. */
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/* Try JOHAB Hangul. */
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ret = johab_hangul_wctomb(conv,buf,wc,2);
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if (ret != RET_ILUNI) {
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if (ret != 2) abort();
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if (n < 2)
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return RET_TOOSMALL;
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r[0] = buf[0];
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r[1] = buf[1];
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return 2;
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}
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/* Try KSC5601, now KS X 1001. */
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ret = ksc5601_wctomb(conv,buf,wc,2);
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if (ret != RET_ILUNI) {
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unsigned char c1, c2;
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if (ret != 2) abort();
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if (n < 2)
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return RET_TOOSMALL;
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c1 = buf[0];
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c2 = buf[1];
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if (((c1 >= 0x21 && c1 <= 0x2c) || (c1 >= 0x4a && c1 <= 0x7d))
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&& (c2 >= 0x21 && c2 <= 0x7e)) {
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unsigned int t = (c1 < 0x4A ? (c1-0x21+0x1B2) : (c1-0x21+0x197));
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unsigned char t2 = ((t & 1) ? 0x5e : 0) + (c2 - 0x21);
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r[0] = t >> 1;
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r[1] = (t2 < 0x4e ? t2+0x31 : t2+0x43);
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return 2;
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}
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}
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return RET_ILUNI;
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}
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