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Diffstat (limited to 'utf8.cc')
| -rw-r--r-- | utf8.cc | 149 |
1 files changed, 149 insertions, 0 deletions
@@ -0,0 +1,149 @@ +// Copyright (C) 2003 Mooffie <mooffie@typo.co.il> +// +// This program is free software; you can redistribute it and/or modify +// it under the terms of the GNU General Public License as published by +// the Free Software Foundation; either version 2 of the License, or +// (at your option) any later version. +// +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License +// along with this program; if not, write to the Free Software +// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA. + +#include <config.h> + +#include "utf8.h" +#include "univalues.h" +#include "dbg.h" + +// utf8_to_unicode() - converts a UTF-8 string to unichars. When an +// incomplete sequence is encountered, *problem will point to its head (it's +// similar to what iconv does). +// +// This function converts UTF-8 to UCS-4 (not to UTF-32) -- that's why it +// recognizes 5- and 6-byte sequences. + +int utf8_to_unicode(unichar *dest, const char *s, int len, const char **problem) +{ + int length = 0; + const char *end = s + len; + + if (problem) + *problem = NULL; + +// constant expressions are evaluated at compile time, of course. +#define FRST(t) ((*s & ((1 << (8-t-1)) - 1)) << (t-1)*6) +#define UC(t,n) (*(s+n-1) & 0x3F) << ((t-n)*6) + while (s < end) { + if (!(*s & 0x80)) { + *dest++ = *s; + s++; + } else if ((*s & 0xE0) == 0xC0) { + if ((end - s) >= 2) { + *dest++ = FRST(2) | UC(2,2); + s += 2; + } else { + if (problem) + *problem = s; + break; + } + } else if ((*s & 0xF0) == 0xE0) { + if ((end - s) >= 3) { + *dest++ = FRST(3) | UC(3,2) | UC(3,3); + s += 3; + } else { + if (problem) + *problem = s; + break; + } + } else if ((*s & 0xF8) == 0xF0) { + if ((end - s) >= 4) { + *dest++ = FRST(4) | UC(4,2) | UC(4,3) | UC(4,4); + s += 4; + } else { + if (problem) + *problem = s; + break; + } + } else if ((*s & 0xFC) == 0xF8) { + if ((end - s) >= 5) { + *dest++ = FRST(5) | UC(5,2) | UC(5,3) | UC(5,4) | UC(5,5); + s += 5; + } else { + if (problem) + *problem = s; + break; + } + } else if ((*s & 0xFE) == 0xFC) { + if ((end - s) >= 6) { + *dest++ = FRST(6) | UC(6,2) | UC(6,3) | UC(6,4) | UC(6,5) | UC(6,6); + s += 6; + } else { + if (problem) + *problem = s; + break; + } + } else { + *dest++ = UNI_REPLACEMENT; + s++; + } + length++; + } + return length; +#undef FRST +#undef UC +} + +// unicode_to_utf8() - converts unichars to UTF-8. + +int unicode_to_utf8(char *dest, const unichar *us, int len) +{ +#define UC(n) ((*us >> 6*n) & 0x3F) +#define CNT(n) (((1 << n) - 1) << (8 - n)) + int nbytes = 0; + while (len--) { + if (*us < 0x80) { + *dest++ = *us; + nbytes += 1; + } else if (*us < 0x800) { + *dest++ = UC(1) | CNT(2); + *dest++ = UC(0) | 0x80; + nbytes += 2; + } else if (*us < 0x10000) { + *dest++ = UC(2) | CNT(3); + *dest++ = UC(1) | 0x80; + *dest++ = UC(0) | 0x80; + nbytes += 3; + } else if (*us < 0x200000) { + *dest++ = UC(3) | CNT(4); + *dest++ = UC(2) | 0x80; + *dest++ = UC(1) | 0x80; + *dest++ = UC(0) | 0x80; + nbytes += 4; + } else if (*us < 0x4000000) { + *dest++ = UC(4) | CNT(5); + *dest++ = UC(3) | 0x80; + *dest++ = UC(2) | 0x80; + *dest++ = UC(1) | 0x80; + *dest++ = UC(0) | 0x80; + nbytes += 5; + } else { + *dest++ = UC(5) | CNT(6); + *dest++ = UC(4) | 0x80; + *dest++ = UC(3) | 0x80; + *dest++ = UC(2) | 0x80; + *dest++ = UC(1) | 0x80; + *dest++ = UC(0) | 0x80; + nbytes += 6; + } + us++; + } + return nbytes; +#undef UC +#undef CNT +} + |