X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=demo_prior;a=blobdiff_plain;f=libs%2Fdrawtext%2Fsrc%2Futf8.c;fp=libs%2Fdrawtext%2Fsrc%2Futf8.c;h=3ce1b56dca2732baa45fa04ea24b4920a6bf39c8;hp=0000000000000000000000000000000000000000;hb=2f14a35e7d557da12f24056267b911f24774aa18;hpb=5eefe7b94c8d6c6caa2c10e3835ab0831a3c42a1

diff --git a/libs/drawtext/src/utf8.c b/libs/drawtext/src/utf8.c
new file mode 100644
index 0000000..3ce1b56
--- /dev/null
+++ b/libs/drawtext/src/utf8.c
@@ -0,0 +1,174 @@
+/*
+libdrawtext - a simple library for fast text rendering in OpenGL
+Copyright (C) 2011  John Tsiombikas <nuclear@member.fsf.org>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation, either version 3 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 Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+#include "drawtext.h"
+
+#define	U8_IS_FIRST(x)		(((((x) >> 7) & 1) == 0) || ((((x) >> 6) & 3) == 3))
+
+static const char first_mask[] = {
+	0,
+	0x7f,	/* single byte, 7 bits valid */
+	0x1f,	/* two-bytes, 5 bits valid */
+	0xf,	/* three-bytes, 4 bits valid */
+	0x7		/* four-bytes, 3 bits valid */
+};
+static const char first_shift[] = { 0, 7, 5, 4, 3 };	/* see above */
+
+#define CONT_PREFIX	0x80
+#define CONT_MASK	0x3f
+#define CONT_SHIFT	6
+
+/* last charcodes for 1, 2, 3 or 4-byte utf8 chars */
+static const int utf8_lastcode[] = { 0x7f, 0x7ff, 0xfff, 0x1fffff };
+
+#define prefix_mask(x)	(~first_mask[x])
+#define prefix(x)		((prefix_mask(x) << 1) & 0xff)
+
+
+char *dtx_utf8_next_char(char *str)
+{
+	return str + dtx_utf8_nbytes(str);
+}
+
+char *dtx_utf8_prev_char(char *ptr, char *first)
+{
+	do {
+		--ptr;
+	} while(!U8_IS_FIRST(*ptr) && ptr > first);
+	return ptr;
+}
+
+int dtx_utf8_char_code(const char *str)
+{
+	int i, nbytes, shift, code = 0;
+	int mask;
+
+	if(!U8_IS_FIRST(*str)) {
+		return -1;
+	}
+
+	nbytes = dtx_utf8_nbytes(str);
+	mask = first_mask[nbytes];
+	shift = 0;
+
+	for(i=0; i<nbytes; i++) {
+		if(!*str) {
+			break;
+		}
+
+		code = (code << shift) | (*str++ & mask);
+		mask = 0x3f;
+		shift = 6;
+	}
+	return code;
+}
+
+int dtx_utf8_nbytes(const char *str)
+{
+	int i, numset = 0;
+	int c = *str;
+
+	if(!U8_IS_FIRST(c)) {
+		for(i=0; !U8_IS_FIRST(str[i]); i++);
+		return i;
+	}
+
+	/* count the leading 1s */
+	for(i=0; i<4; i++) {
+		if(((c >> (7 - i)) & 1) == 0) {
+			break;
+		}
+		numset++;
+	}
+
+	if(!numset) {
+		return 1;
+	}
+	return numset;
+}
+
+int dtx_utf8_char_count(const char *str)
+{
+	int n = 0;
+
+	while(*str) {
+		++n;
+		str = dtx_utf8_next_char((char*)str);
+	}
+	return n;
+}
+
+int dtx_utf8_char_count_range(const char *str, int nbytes)
+{
+	int n = 0;
+	while(*str && nbytes > 0) {
+		char *next = dtx_utf8_next_char((char*)str);
+		++n;
+		nbytes -= next - str;
+		str = next;
+	}
+	return (nbytes < 0 && n > 0) ? n - 1 : n;
+}
+
+size_t dtx_utf8_from_char_code(int code, char *buf)
+{
+	size_t nbytes = 0;
+	int i;
+
+	for(i=0; i<4; i++) {
+		if(code <= utf8_lastcode[i]) {
+			nbytes = i + 1;
+			break;
+		}
+	}
+
+	if(!nbytes && buf) {
+		for(i=0; i<(int)nbytes; i++) {
+			int idx = nbytes - i - 1;
+			int mask, shift, prefix;
+
+			if(idx > 0) {
+				mask = CONT_MASK;
+				shift = CONT_SHIFT;
+				prefix = CONT_PREFIX;
+			} else {
+				mask = first_mask[nbytes];
+				shift = first_shift[nbytes];
+				prefix = prefix(nbytes);
+			}
+
+			buf[idx] = (code & mask) | (prefix & ~mask);
+			code >>= shift;
+		}
+	}
+	return nbytes;
+}
+
+size_t dtx_utf8_from_string(const wchar_t *str, char *buf)
+{
+	size_t nbytes = 0;
+	char *ptr = buf;
+
+	while(*str) {
+		int cbytes = dtx_utf8_from_char_code(*str++, ptr);
+		if(ptr) {
+			ptr += cbytes;
+		}
+		nbytes += cbytes;
+	}
+	return nbytes;
+}