Interpret patterns where the first byte of the mask is '*' as unanchored.

2005-07-22  Matthias Clasen  <mclasen@redhat.com>

	* gdk-pixbuf-io.c (format_check): Interpret patterns where
	the first byte of the mask is '*' as unanchored.  (#311011)
	(gdk_pixbuf_new_from_file): Use the first 256 bytes for
	sniffing the file format.

docs/reference/ChangeLog

@@ -1,3 +1,8 @@
+2005-07-22  Matthias Clasen  <mclasen@redhat.com>
+
+	* gdk-pixbuf/tmpl/module_interface.sgml: Document unanchored 
+	patterns.
+
 2005-07-21  Federico Mena Quintero  <federico@ximian.com>
 
 	* gtk/tmpl/gtkfilechooserdialog.sgml (dialog): Expand the Save

docs/reference/gdk-pixbuf/tmpl/module_interface.sgml

@@ -204,14 +204,19 @@ operations.
 <!-- ##### STRUCT GdkPixbufModulePattern ##### -->
 <para>
 The signature of a module is a set of prefixes. Prefixes are encoded as
-pairs of ordinary strings, where the second string, if not %NULL, must be
+pairs of ordinary strings, where the second string, called the mask, if 
-of the same length as the first one and may contain ' ', '!', 'x', 'z', 
+not %NULL, must be of the same length as the first one and may contain 
-and 'n' to indicate bytes that must be matched, not matched, 
+' ', '!', 'x', 'z', and 'n' to indicate bytes that must be matched, 
-"don't-care"-bytes, zeros and non-zeros.
+not matched, "don't-care"-bytes, zeros and non-zeros. 
 Each prefix has an associated integer that describes the relevance of 
 the prefix, with 0 meaning a mismatch and 100 a "perfect match".
 </para>
-
+<para>
+Starting with &gdk-pixbuf; 2.8, the first byte of the mask may be '*', 
+indicating an unanchored pattern that matches not only at the beginning, 
+but also in the middle. Versions prior to 2.8 will interpret the '*'
+like an 'x'. 
+</para>
 <para>
 The signature of a module is stored as an array of 
 #GdkPixbufModulePattern<!-- -->s. The array is terminated by a pattern

gdk-pixbuf/ChangeLog

@@ -1,3 +1,10 @@
+2005-07-22  Matthias Clasen  <mclasen@redhat.com>
+
+	* gdk-pixbuf-io.c (format_check): Interpret patterns where
+	the first byte of the mask is '*' as unanchored.  (#311011)
+	(gdk_pixbuf_new_from_file): Use the first 256 bytes for
+	sniffing the file format.
+
 2005-07-15  Matthias Clasen  <mclasen@redhat.com>
 
 	* === Released 2.7.3 ===

gdk-pixbuf/gdk-pixbuf-io.c

@@ -48,33 +48,47 @@
 static gint 
 format_check (GdkPixbufModule *module, guchar *buffer, int size)
 {
-	int j;
+	int i, j;
 	gchar m;
 	GdkPixbufModulePattern *pattern;
+	gboolean unanchored;
+	guchar *prefix, *mask;
 
 	for (pattern = module->info->signature; pattern->prefix; pattern++) {
-		for (j = 0; j < size && pattern->prefix[j] != 0; j++) {
+		if (pattern->mask && pattern->mask[0] == '*') {
-			m = pattern->mask ? pattern->mask[j] : ' ';
+			prefix = pattern->prefix + 1;
+			mask = pattern->mask + 1;
+			unanchored = TRUE;
+		}
+		else {
+			prefix = pattern->prefix;
+			mask = pattern->mask;
+			unanchored = FALSE;
+		}
+		for (i = 0; unanchored && i < size; i++) {
+			for (j = 0; i + j < size && prefix[j] != 0; j++) {
+				m = mask ? mask[j] : ' ';
 				if (m == ' ') {
-				if (buffer[j] != pattern->prefix[j])
+					if (buffer[i + j] != prefix[j])
 						break;
 				}
 				else if (m == '!') {
-				if (buffer[j] == pattern->prefix[j])
+					if (buffer[i + j] == prefix[j])
 						break;
 				}
 				else if (m == 'z') {
-				if (buffer[j] != 0)
+					if (buffer[i + j] != 0)
 						break;
 				}
 				else if (m == 'n') {
-				if (buffer[j] == 0)
+					if (buffer[i + j] == 0)
 						break;
 				}
 			} 
-		if (pattern->prefix[j] == 0) 
+			if (prefix[j] == 0) 
 				return pattern->relevance;
 		}
+	}
 	return 0;
 }
 
@@ -821,7 +835,7 @@ gdk_pixbuf_new_from_file (const char *filename,
 	GdkPixbuf *pixbuf;
 	int size;
 	FILE *f;
-	guchar buffer [128];
+	guchar buffer[256];
 	GdkPixbufModule *image_module;
 	gchar *display_name;