Bidi stability work. I _think_ I've now removed all the failures of

[PuTTY_svn.git] / minibidi.c

diff --git a/minibidi.c b/minibidi.c
index d48dbff17d7407a306650a1e30305390fcd4b71f..566f3fd4ee22014251f1ce2cc8d59c2caea4fead 100644 (file)
--- a/minibidi.c
+++ b/minibidi.c
@@ -31,6 +31,8 @@
 
 #include "minibidi.h"
 
+#define lenof(x) ( sizeof((x)) / sizeof(*(x)) )
+
 /*
  * Flips the text buffer, according to max level, and
  * all higher levels
@@ -110,17 +112,25 @@ unsigned char setOverrideBits(unsigned char level, unsigned char override)
     return level;
 }
 
-/* Dont remember what this was used for :-) */
-unsigned char getPreviousLevel(unsigned char* level, int from)
+/*
+ * Find the most recent run of the same value in `level', and
+ * return the value _before_ it. Used to process U+202C POP
+ * DIRECTIONAL FORMATTING.
+ */
+int getPreviousLevel(unsigned char* level, int from)
 {
-    unsigned char current;
-    from--;
-    current = level[from];
-    while(from>0 && level[from] == current)
-    {
-       from--;
-    }
-    return level[++from];
+    if (from > 0) {
+        unsigned char current = level[--from];
+
+        while (from >= 0 && level[from] == current)
+            from--;
+
+        if (from >= 0)
+            return level[from];
+
+        return -1;
+    } else
+        return -1;
 }
 
 /*
@@ -151,19 +161,16 @@ unsigned char leastGreaterEven(unsigned char x)
  */
 unsigned char getRLE(wchar_t ch)
 {
-    int offset, i, freq;
+    int offset, i;
 
-    freq = offset = 0;
-    for(i=0; i<0xFFFF; i++)
+    offset = 0;
+    for(i=0; i<lenof(RLE_table); i++)
     {
-       freq = ((RLENode*)RLE_table)[i].f;
-       offset += freq;
-       if(offset == ch)
-           return ((RLENode*)RLE_table)[i].d;
-       else if(offset > ch)
-           return ((RLENode*)RLE_table)[i-1].d;
+       offset += RLE_table[i].f;
+       if(ch < offset)
+           return RLE_table[i].d;
     }
-    /* this is here to stop compiler nagging */
+    /* anything beyond the end of the table is unknown */
     return ON;
 }
 
@@ -191,7 +198,7 @@ int do_shape(bidi_char *line, bidi_char *to, int count)
            break;
 
          case SR:
-           tempShape = STYPE(line[i+1].wc);
+           tempShape = (i+1 < count ? STYPE(line[i+1].wc) : SU);
            if((tempShape == SL) || (tempShape == SD) || (tempShape == SC))
                to[i].wc = SFINAL((SISOLATED(line[i].wc)));
            else
@@ -201,10 +208,10 @@ int do_shape(bidi_char *line, bidi_char *to, int count)
 
          case SD:
            /* Make Ligatures */
-           tempShape = STYPE(line[i+1].wc);
+           tempShape = (i+1 < count ? STYPE(line[i+1].wc) : SU);
            if(line[i].wc == 0x644)
            {
-               switch(line[i-1].wc)
+               if (i > 0) switch(line[i-1].wc)
                {
                  case 0x622:
                    ligFlag = 1;
@@ -245,7 +252,7 @@ int do_shape(bidi_char *line, bidi_char *to, int count)
 
            if((tempShape == SL) || (tempShape == SD) || (tempShape == SC))
            {
-               tempShape = STYPE(line[i-1].wc);
+                tempShape = (i > 0 ? STYPE(line[i-1].wc) : SU);
                if((tempShape == SR) || (tempShape == SD) || (tempShape == SC))
                    to[i].wc = SMEDIAL( (SISOLATED(line[i].wc)) );
                else
@@ -253,7 +260,7 @@ int do_shape(bidi_char *line, bidi_char *to, int count)
                break;
            }
 
-           tempShape = STYPE(line[i-1].wc);
+            tempShape = (i > 0 ? STYPE(line[i-1].wc) : SU);
            if((tempShape == SR) || (tempShape == SD) || (tempShape == SC))
                to[i].wc = SINITIAL((SISOLATED(line[i].wc)));
            else
@@ -380,9 +387,17 @@ int do_bidi(bidi_char *line, int count)
            break;
 
          case PDF:
-           currentEmbedding = getPreviousLevel(levels, i);
-           currentOverride = currentEmbedding & OMASK;
-           currentEmbedding = currentEmbedding & ~OMASK;
+            {
+                int prevlevel = getPreviousLevel(levels, i);
+
+                if (prevlevel == -1) {
+                    currentEmbedding = paragraphLevel;
+                    currentOverride = ON;
+                } else {
+                    currentOverride = currentEmbedding & OMASK;
+                    currentEmbedding = currentEmbedding & ~OMASK;
+                }
+            }
            levels[i] = currentEmbedding;
            break;
 
@@ -487,7 +502,7 @@ int do_bidi(bidi_char *line, int count)
      * to a European number. A single common separator between two numbers
      * of the same type changes to that type.
      */
-    for( i=0; i<(count-1); i++)
+    for( i=1; i<(count-1); i++)
     {
        if(types[i] == ES)
        {
@@ -512,15 +527,15 @@ int do_bidi(bidi_char *line, int count)
     {
        if(types[i] == ET)
        {
-           if(types[i-1] == EN)
+           if(i > 0 && types[i-1] == EN)
            {
                types[i] = EN;
                continue;
-           }else if(types[i+1] == EN)
+           }else if(i < count-1 && types[i+1] == EN)
                {
                    types[i] = EN;
                    continue;
-               }else if(types[i+1] == ET)
+               }else if(i < count-1 && types[i+1] == ET)
                    {
                        j=i;
                        while(j <count && types[j] == ET)
@@ -579,7 +594,7 @@ int do_bidi(bidi_char *line, int count)
      * strong text if the text on both sides has the same direction. European
      * and Arabic numbers are treated as though they were R.
      */
-    if(types[0] == ON)
+    if(count >= 2 && types[0] == ON)
     {
        if((types[1] == R) || (types[1] == EN) || (types[1] == AN))
            types[0] = R;
@@ -628,7 +643,7 @@ int do_bidi(bidi_char *line, int count)
                }
        }
     }
-    if(types[count-1] == ON)
+    if(count >= 2 && types[count-1] == ON)
     {
        if(types[count-2] == R || types[count-2] == EN || types[count-2] == AN)
            types[count-1] = R;