Patch #783877 by Gadi Cohen updated by Naftali Goldstein - Bidirectional text support for Hebrew and Arabic

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@7292 a1c6a512-1295-4272-9138-f99709370657

firmware/bidi.c

@@ -0,0 +1,184 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2005 by Gadi Cohen
+ *
+ * Largely based on php_hebrev by Zeev Suraski <zeev@php.net>
+ * Heavily modified by Gadi Cohen aka Kinslayer <dragon@wastelands.net>
+ *
+ * All files in this archive are subject to the GNU General Public License.
+ * See the file COPYING in the source tree root for full license agreement.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+#include "file.h"
+#include "lcd.h"
+
+#define _HEB_BUFFER_LENGTH MAX_PATH + LCD_WIDTH/2 + 3 + 2 + 2
+#define _HEB_BLOCK_TYPE_ENG 1
+#define _HEB_BLOCK_TYPE_HEB 0
+#define _HEB_ORIENTATION_LTR 1
+#define _HEB_ORIENTATION_RTL 0
+
+#define ischar(c) (((((unsigned char) c)>=193) && (((unsigned char) c)<=250)) ? 1 : 0)
+#define _isblank(c) (((((unsigned char) c)==' ' || ((unsigned char) c)=='\t')) ? 1 : 0)
+#define _isnewline(c) (((((unsigned char) c)=='\n' || ((unsigned char) c)=='\r')) ? 1 : 0)
+#define XOR(a,b) ((a||b) && !(a&&b))
+
+bool bidi_support_enabled = false;
+
+unsigned char *bidi_l2v(const unsigned char *str, int orientation)
+{
+    static unsigned char buf_heb_str[_HEB_BUFFER_LENGTH];
+    static unsigned char  buf_broken_str[_HEB_BUFFER_LENGTH];
+    const unsigned char *tmp;
+    unsigned char *heb_str, *target, *opposite_target, *broken_str;
+    int block_start, block_end, block_type, block_length, i;
+    int block_ended;
+    long max_chars=0;
+    int begin, end, char_count, orig_begin;
+
+    if (!str || !*str)
+        return "";
+
+    tmp = str;
+    block_start=block_end=0;
+    block_ended=0;
+
+    heb_str = buf_heb_str;
+    if (orientation) {
+        target = heb_str;
+        opposite_target = heb_str + strlen(str);
+    } else {
+        target = heb_str + strlen(str);
+        opposite_target = heb_str;
+        *target = 0;
+        target--;
+    }
+    
+    block_length=0;
+    if (ischar(*tmp))
+        block_type = _HEB_BLOCK_TYPE_HEB;
+    else
+        block_type = _HEB_BLOCK_TYPE_ENG;
+    
+    do {
+        while((XOR(ischar((int)*(tmp+1)),block_type)
+               || _isblank((int)*(tmp+1)) || ispunct((int)*(tmp+1))
+               || (int)*(tmp+1)=='\n')
+              && block_end<(int)strlen(str)-1) {
+            tmp++;
+            block_end++;
+            block_length++;
+        }
+        
+        if (block_type != orientation) {
+            while ((_isblank((int)*tmp) || ispunct((int)*tmp))
+                   && *tmp!='/' && *tmp!='-' && block_end>block_start) {
+                tmp--;
+                block_end--;
+            }
+        }
+        
+        for (i=block_start; i<=block_end; i++) {
+            *target = (block_type == orientation) ? *(str+i) : *(str+block_end-i+block_start);
+            if (block_type!=orientation) {
+                switch (*target) {
+                case '(':
+                    *target = ')';
+                    break;
+                case ')':
+                    *target = '(';
+                    break;
+                default:
+                    break;
+                }
+            }
+            target += orientation ? 1 : -1;
+        }
+        block_type = !block_type;
+        block_start=block_end+1;
+    } while(block_end<(int)strlen(str)-1);
+    
+    broken_str = buf_broken_str;
+    begin=end=strlen(str)-1;
+    target = broken_str;
+    
+    while (1) {
+        char_count=0;
+        while ((!max_chars || char_count<max_chars) && begin>0) {
+            char_count++;
+            begin--;
+            if (begin<=0 || _isnewline(heb_str[begin])) {
+                while(begin>0 && _isnewline(heb_str[begin-1])) {
+                    begin--;
+                    char_count++;
+                }
+                break;
+            }
+        }
+        if (char_count==max_chars) { /* try to avoid breaking words */
+            int new_char_count = char_count;
+            int new_begin = begin;
+            
+            while (new_char_count>0) {
+                if (_isblank(heb_str[new_begin]) ||
+                    _isnewline(heb_str[new_begin])) {
+                    break;
+                }
+                new_begin++;
+                new_char_count--;
+            }
+            if (new_char_count>0) {
+                char_count=new_char_count;
+                begin=new_begin;
+            }
+        }
+        orig_begin=begin;
+        
+        if (_isblank(heb_str[begin])) {
+            heb_str[begin]='\n';
+        }
+        
+        /* skip leading newlines */
+        while (begin<=end && _isnewline(heb_str[begin])) {
+            begin++;
+        }
+
+        /* copy content */
+        for (i=begin; i<=end; i++) {
+            *target = heb_str[i];
+            target++;
+        }
+
+        for (i=orig_begin; i<=end && _isnewline(heb_str[i]); i++) {
+            *target = heb_str[i];
+            target++;
+        }
+        begin=orig_begin;
+        
+        if (begin<=0) {
+            *target = 0;
+            break;
+        }
+        begin--;
+        end=begin;
+    }
+    return broken_str;
+}
+
+void set_bidi_support(bool setting)
+{
+    bidi_support_enabled = setting;
+}