Change FcCharSetMerge API

To only work on writable charsets.  Also, return a bool indicating whether
the merge changed the charset.

Also changes the implementation of FcCharSetMerge and FcCharSetIsSubset

doc/fccharset.fncs

@@ -98,17 +98,19 @@ Returns a set including only those chars found in either <parameter>a</parameter
 Returns a set including only those chars found in <parameter>a</parameter> but not <parameter>b</parameter>. 
 @@
 
-@RET@		FcCharSet *
+@RET@		FcBool
 @FUNC@		FcCharSetMerge
-@TYPE1@		const FcCharSet *	@ARG1@		a
+@TYPE1@		FcCharSet *		@ARG1@		a
 @TYPE2@		const FcCharSet *	@ARG2@		b
+@TYPE3@		FcBool *		@ARG3@		changed
 @PURPOSE@	Merge charsets
 @DESC@
-If <parameter>a</parameter> is NULL, returns a newly-created copy of <parameter>b</parameter>.
+Adds all chars in <parameter>b</parameter> to <parameter>a</parameter>.
-If <parameter>a</parameter> is an FcCharSet object owned by fontconfig that
+In other words, this is an in-place version of FcCharSetUnion.
-cannot be modified, it returns the union of <parameter>a</parameter> and
+If <parameter>changed</parameter> is not NULL, then it returns whether any new
-<parameter>b</parameter> in a newly-created FcCharSet object.
+chars from <parameter>b</parameter> were added to <parameter>a</parameter>.
-Otherwise, adds all chars in <parameter>b</parameter> to <parameter>a</parameter> and returns <parameter>a</parameter>.  In other words, this is an in-place versionof FcCharSetUnion.
+Returns FcFalse on failure, either when <parameter>a</parameter> is a constant
+set or from running out of memory.
 @@
 
 @RET@		FcBool 

fontconfig/fontconfig.h

@@ -439,8 +439,8 @@ FcCharSetUnion (const FcCharSet *a, const FcCharSet *b);
 FcPublic FcCharSet*
 FcCharSetSubtract (const FcCharSet *a, const FcCharSet *b);
 
-FcPublic FcCharSet *
+FcPublic FcBool
-FcCharSetMerge (FcCharSet *a, const FcCharSet *b);
+FcCharSetMerge (FcCharSet *a, const FcCharSet *b, FcBool *changed);
 
 FcPublic FcBool
 FcCharSetHasChar (const FcCharSet *fcs, FcChar32 ucs4);

src/fccharset.c

@@ -80,6 +80,39 @@ FcCharSetDestroy (FcCharSet *fcs)
     free (fcs);
 }
 
+/*
+ * Search for the leaf containing with the specified num.
+ * Return its index if it exists, otherwise return negative of
+ * the (position + 1) where it should be inserted
+ */
+
+
+static int
+FcCharSetFindLeafForward (const FcCharSet *fcs, int start, FcChar16 num)
+{
+    FcChar16		*numbers = FcCharSetNumbers(fcs);
+    FcChar16		page;
+    int			low = start;
+    int			high = fcs->num - 1;
+
+    if (!numbers)
+	return -1;
+    while (low <= high)
+    {
+	int mid = (low + high) >> 1;
+	page = numbers[mid];
+	if (page == num)
+	    return mid;
+	if (page < num)
+	    low = mid + 1;
+	else
+	    high = mid - 1;
+    }
+    if (high < 0 || (high < fcs->num && numbers[high] < num))
+	high++;
+    return -(high + 1);
+}
+
 /*
  * Locate the leaf containing the specified char, return
  * its index if it exists, otherwise return negative of
@@ -89,28 +122,7 @@ FcCharSetDestroy (FcCharSet *fcs)
 static int
 FcCharSetFindLeafPos (const FcCharSet *fcs, FcChar32 ucs4)
 {
-    FcChar16		*numbers = FcCharSetNumbers(fcs);
+    return FcCharSetFindLeafForward (fcs, 0, ucs4 >> 8);
-    FcChar16		page;
-    int			low = 0;
-    int			high = fcs->num - 1;
-
-    if (!numbers)
-	return -1;
-    ucs4 >>= 8;
-    while (low <= high)
-    {
-	int mid = (low + high) >> 1;
-	page = numbers[mid];
-	if (page == ucs4)
-	    return mid;
-	if (page < ucs4)
-	    low = mid + 1;
-	else
-	    high = mid - 1;
-    }
-    if (high < 0 || (high < fcs->num && numbers[high] < ucs4))
-	high++;
-    return -(high + 1);
 }
 
 static FcCharLeaf *
@@ -452,67 +464,52 @@ FcCharSetUnion (const FcCharSet *a, const FcCharSet *b)
     return FcCharSetOperate (a, b, FcCharSetUnionLeaf, FcTrue, FcTrue);
 }
 
-FcCharSet *
+FcBool
-FcCharSetMerge (FcCharSet *a, const FcCharSet *b)
+FcCharSetMerge (FcCharSet *a, const FcCharSet *b, FcBool *changed)
 {
-    FcCharSet	    *fcs;
+    int		ai = 0, bi = 0;
-    FcCharSetIter    ai, bi;
+    FcChar16	an, bn;
 
-    if (a == NULL) {
+    if (a->ref == FC_REF_CONSTANT)
-	fcs = a = FcCharSetCreate ();
+	return FcFalse;
-    } else if (a->ref == FC_REF_CONSTANT) {
-	fcs = FcCharSetCreate ();
-    } else
-	fcs = a;
 
-    if (fcs == NULL)
+    if (changed) {
-	return NULL;
+	*changed = !FcCharSetIsSubset(b, a);
-
+	if (!*changed)
-    FcCharSetIterStart (a, &ai);
+	    return FcTrue;
-    FcCharSetIterStart (b, &bi);
-    while (ai.leaf || bi.leaf)
-    {
-	if (ai.ucs4 < bi.ucs4)
-	{
-	    if (!FcCharSetAddLeaf (fcs, ai.ucs4, ai.leaf))
-		goto bail;
-
-	    FcCharSetIterNext (a, &ai);
     }
-	else if (bi.ucs4 < ai.ucs4)
-	{
-	    if (!FcCharSetAddLeaf (fcs, bi.ucs4, bi.leaf))
-		goto bail;
 
-	    FcCharSetIterNext (b, &bi);
+    while (bi < b->num)
+    {
+	an = ai < a->num ? FcCharSetNumbers(a)[ai] : ~0;
+	bn = FcCharSetNumbers(b)[bi];
+
+	if (an < bn)
+	{
+	    ai = FcCharSetFindLeafForward (a, ai + 1, bn);
+	    if (ai < 0)
+		ai = -ai - 1;
 	}
 	else
 	{
-	    FcCharLeaf  leaf;
+	    FcCharLeaf *bl = FcCharSetLeaf(b, bi);
-
+	    if (bn < an)
-	    if (FcCharSetUnionLeaf (&leaf, ai.leaf, bi.leaf))
 	    {
-		if (!FcCharSetAddLeaf (fcs, ai.ucs4, &leaf))
+		if (!FcCharSetAddLeaf (a, bn << 8, bl))
-		    goto bail;
+		    return FcFalse;
+	    }
+	    else
+	    {
+		FcCharLeaf *al = FcCharSetLeaf(a, ai);
+		FcCharSetUnionLeaf (al, al, bl);
 	    }
 
-	    FcCharSetIterNext (a, &ai);
+	    ai++;
-	    FcCharSetIterNext (b, &bi);
+	    bi++;
 	}
     }
 
-    if (fcs != a)
+    return FcTrue;
-	FcCharSetDestroy (a);
-
-    return fcs;
-
-bail:
-    FcCharSetDestroy (fcs);
-
-    if (fcs != a)
-	FcCharSetDestroy (a);
-
-    return NULL;
 }
 
 static FcBool
@@ -687,29 +684,9 @@ FcCharSetIsSubset (const FcCharSet *a, const FcCharSet *b)
 	    return FcFalse;
 	else
 	{
-	    int	    low = bi + 1;
+	    bi = FcCharSetFindLeafForward (b, bi + 1, an);
-	    int	    high = b->num - 1;
+	    if (bi < 0)
-
+		bi = -bi - 1;
-	    /*
-	     * Search for page 'an' in 'b'
-	     */
-	    while (low <= high)
-	    {
-		int mid = (low + high) >> 1;
-		bn = FcCharSetNumbers(b)[mid];
-		if (bn == an)
-		{
-		    high = mid;
-		    break;
-		}
-		if (bn < an)
-		    low = mid + 1;
-		else
-		    high = mid - 1;
-	    }
-	    bi = high;
-	    while (bi < b->num && FcCharSetNumbers(b)[bi] < an)
-		bi++;
 	}
     }
     /*

src/fcmatch.c

@@ -606,38 +606,45 @@ FcSortCompare (const void *aa, const void *ab)
 }
 
 static FcBool
-FcSortWalk (FcSortNode **n, int nnode, FcFontSet *fs, FcCharSet **cs, FcBool trim, FcBool build_cs)
+FcSortWalk (FcSortNode **n, int nnode, FcFontSet *fs, FcCharSet **csp, FcBool trim)
 {
-    FcCharSet	*ncs;
+    FcBool ret = FcFalse;
-    FcSortNode	*node;
+    FcCharSet *cs;
+
+    cs = 0;
+    if (trim || csp)
+    {
+	cs = FcCharSetCreate ();
+	if (cs == NULL)
+	    goto bail;
+    }
 
     while (nnode--)
     {
-	node = *n++;
+	FcSortNode	*node = *n++;
+	FcBool		adds_chars = FcFalse;
 
 	/*
 	 * Only fetch node charset if we'd need it
 	 */
-	if (trim || build_cs)
+	if (cs)
 	{
+	    FcCharSet	*ncs;
+
 	    if (FcPatternGetCharSet (node->pattern, FC_CHARSET, 0, &ncs) !=
 		FcResultMatch)
 	        continue;
+
+	    if (!FcCharSetMerge (cs, ncs, &adds_chars))
+		goto bail;
 	}
 
 	/*
 	 * If this font isn't a subset of the previous fonts,
 	 * add it to the list
 	 */
-	if (!trim || !*cs || !FcCharSetIsSubset (ncs, *cs))
+	if (!trim || adds_chars)
 	{
-	    if (trim || build_cs)
-	    {
-		*cs = FcCharSetMerge (*cs, ncs);
-		if (*cs == NULL)
-		    return FcFalse;
-	    }
-
 	    FcPatternReference (node->pattern);
 	    if (FcDebug () & FC_DBG_MATCHV)
 	    {
@@ -647,11 +654,23 @@ FcSortWalk (FcSortNode **n, int nnode, FcFontSet *fs, FcCharSet **cs, FcBool tri
 	    if (!FcFontSetAdd (fs, node->pattern))
 	    {
 		FcPatternDestroy (node->pattern);
-		return FcFalse;
+		goto bail;
 	    }
 	}
     }
-    return FcTrue;
+    if (csp)
+    {
+	*csp = cs;
+	cs = 0;
+    }
+
+    ret = FcTrue;
+
+bail:
+    if (cs)
+	FcCharSetDestroy (cs);
+
+    return ret;
 }
 
 void
@@ -675,7 +694,6 @@ FcFontSetSort (FcConfig	    *config,
     FcSortNode	    **nodeps, **nodep;
     int		    nnodes;
     FcSortNode	    *new;
-    FcCharSet	    *cs;
     int		    set;
     int		    f;
     int		    i;
@@ -803,19 +821,9 @@ FcFontSetSort (FcConfig	    *config,
     if (!ret)
 	goto bail1;
 
-    cs = 0;
+    if (!FcSortWalk (nodeps, nnodes, ret, csp, trim))
-
-    if (!FcSortWalk (nodeps, nnodes, ret, &cs, trim, (csp!=0)))
 	goto bail2;
 
-    if (csp)
-	*csp = cs;
-    else
-    {
-        if (cs)
-            FcCharSetDestroy (cs);
-    }
-
     free (nodes);
 
     if (FcDebug() & FC_DBG_MATCH)
@@ -826,8 +834,6 @@ FcFontSetSort (FcConfig	    *config,
     return ret;
 
 bail2:
-    if (cs)
-	FcCharSetDestroy (cs);
     FcFontSetDestroy (ret);
 bail1:
     free (nodes);