- added libdrawtext

[demo_prior] / libs / drawtext / src / utf8.c

diff --git a/libs/drawtext/src/utf8.c b/libs/drawtext/src/utf8.c
new file mode 100644 (file)
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;
+}