7684ddcfd8
This change rewrites and simplifies the copyright headers at the top of all source files: * Remove "Emacs style mode select" line; this line was included in the headers for the originally released source files and appears to be to set the file type for old versions of Emacs. I'm not sure entirely why it was required but I don't think it is any more. * Remove "You should have received a copy of..." text from copyright header. This refers to the old 59 Temple Place address where the FSF headquarters used to be located and is no longer correct. Rather than change to the new address, just remove the paragraph as it is superfluous anyway. This fixes #311. * Remove ---- separator lines so that the file headers are barer and more simplified.
154 lines
3.4 KiB
C
154 lines
3.4 KiB
C
//
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// Copyright(C) 2005-2014 Simon Howard
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//
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// This program is free software; you can redistribute it and/or
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// modify it under the terms of the GNU General Public License
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// 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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// This program 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
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// GNU General Public License for more details.
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//
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "txt_utf8.h"
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// Encode a Unicode character as UTF-8, storing it in the buffer 'p'
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// and returning the new, incremented position.
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char *TXT_EncodeUTF8(char *p, unsigned int c)
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{
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if (c < 0x80) // 1 character (ASCII):
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{
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p[0] = c;
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return p + 1;
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}
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else if (c < 0x800) // 2 character:
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{
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p[0] = 0xc0 | (c >> 6);
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p[1] = 0x80 | (c & 0x3f);
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return p + 2;
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}
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else if (c < 0x10000) // 3 chacater:
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{
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p[0] = 0xe0 | (c >> 12);
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p[1] = 0x80 | ((c >> 6) & 0x3f);
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p[2] = 0x80 | (c & 0x3f);
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return p + 3;
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}
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else if (c < 0x200000) // 4 character:
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{
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p[0] = 0xf0 | (c >> 18);
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p[1] = 0x80 | ((c >> 12) & 0x3f);
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p[2] = 0x80 | ((c >> 6) & 0x3f);
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p[3] = 0x80 | (c & 0x3f);
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return p + 4;
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}
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else
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{
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// Too big!
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return p;
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}
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}
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// Decode UTF-8 character, incrementing *ptr over the decoded bytes.
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unsigned int TXT_DecodeUTF8(const char **ptr)
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{
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const char *p = *ptr;
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unsigned int c;
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// UTF-8 decode.
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if ((*p & 0x80) == 0) // 1 character (ASCII):
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{
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c = *p;
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*ptr += 1;
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}
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else if ((p[0] & 0xe0) == 0xc0 // 2 character:
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&& (p[1] & 0xc0) == 0x80)
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{
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c = ((p[0] & 0x1f) << 6)
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| (p[1] & 0x3f);
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*ptr += 2;
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}
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else if ((p[0] & 0xf0) == 0xe0 // 3 character:
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&& (p[1] & 0xc0) == 0x80
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&& (p[2] & 0xc0) == 0x80)
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{
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c = ((p[0] & 0x0f) << 12)
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| ((p[1] & 0x3f) << 6)
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| (p[2] & 0x3f);
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*ptr += 3;
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}
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else if ((p[0] & 0xf8) == 0xf0 // 4 character:
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&& (p[1] & 0xc0) == 0x80
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&& (p[2] & 0xc0) == 0x80
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&& (p[3] & 0xc0) == 0x80)
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{
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c = ((p[0] & 0x07) << 18)
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| ((p[1] & 0x3f) << 12)
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| ((p[2] & 0x3f) << 6)
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| (p[3] & 0x3f);
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*ptr += 4;
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}
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else
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{
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// Decode failure.
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// Don't bother with 5/6 byte sequences.
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c = 0;
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}
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return c;
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}
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// Count the number of characters in a UTF-8 string.
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unsigned int TXT_UTF8_Strlen(const char *s)
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{
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const char *p;
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unsigned int result = 0;
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unsigned int c;
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for (p = s; *p != '\0';)
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{
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c = TXT_DecodeUTF8(&p);
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if (c == 0)
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{
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break;
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}
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++result;
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}
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return result;
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}
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// Skip past the first n characters in a UTF-8 string.
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char *TXT_UTF8_SkipChars(const char *s, unsigned int n)
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{
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unsigned int i;
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const char *p;
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p = s;
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for (i = 0; i < n; ++i)
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{
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if (TXT_DecodeUTF8(&p) == 0)
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{
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break;
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}
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}
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return (char *) p;
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}
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