* Moving wfGetSVGSize() and wfScaleSVGUnit() into a seperate SVGMetadataExtractor.

[lhc/web/wiklou.git] / includes / media / GIFMetadataExtractor.php

diff --git a/includes/media/GIFMetadataExtractor.php b/includes/media/GIFMetadataExtractor.php
index 3f17871..bc1a480 100644 (file)
--- a/includes/media/GIFMetadataExtractor.php
+++ b/includes/media/GIFMetadataExtractor.php
@@ -1,20 +1,27 @@
 <?php
 /**
-  * GIF frame counter.
-  * Originally written in Perl by Steve Sanbeg.
-  * Ported to PHP by Andrew Garrett
-  * Deliberately not using MWExceptions to avoid external dependencies, encouraging
-  * redistribution.
-  */
+ * GIF frame counter.
+ *
+ * Originally written in Perl by Steve Sanbeg.
+ * Ported to PHP by Andrew Garrett
+ * Deliberately not using MWExceptions to avoid external dependencies, encouraging
+ * redistribution.
+ *
+ * @file
+ * @ingroup Media
+ */
 
+/**
+ * GIF frame counter.
+ *
+ * @ingroup Media
+ */
 class GIFMetadataExtractor {
        static $gif_frame_sep;
        static $gif_extension_sep;
        static $gif_term;
 
        static function getMetadata( $filename ) {
-               wfProfileIn( __METHOD__ );
-       
                self::$gif_frame_sep = pack( "C", ord("," ) );
                self::$gif_extension_sep = pack( "C", ord("!" ) );
                self::$gif_term = pack( "C", ord(";" ) );
@@ -59,7 +66,7 @@ class GIFMetadataExtractor {
                                // Found a frame
                                $frameCount++;
                                
-                               ## Skip dimensions (Why is this 8 bytes and not 4?)
+                               ## Skip bounding box
                                fread( $fh, 8 );
                                
                                ## Read BPP
@@ -78,6 +85,7 @@ class GIFMetadataExtractor {
                                if ($extension_code == 0xF9) {
                                        // Graphics Control Extension.
                                        fread( $fh, 1 ); // Block size
+                                       
                                        fread( $fh, 1 ); // Transparency, disposal method, user input
                                        
                                        $buf = fread( $fh, 2 ); // Delay, in hundredths of seconds.
@@ -101,11 +109,16 @@ class GIFMetadataExtractor {
                                        
                                        // NETSCAPE2.0 (application name)
                                        if ($blockLength != 11 || $data != 'NETSCAPE2.0') {
-                                               self::skipBlock();
+                                               fseek( $fh, -($blockLength + 1), SEEK_CUR );
+                                               self::skipBlock( $fh );
                                                continue;
                                        }
                                        
-                                       fread( $fh, 2 ); // Block length and introduction, should be 03 01
+                                       $data = fread( $fh, 2 ); // Block length and introduction, should be 03 01
+                                       
+                                       if ($data != "\x03\x01") {
+                                               throw new Exception( "Expected \x03\x01, got $data" );
+                                       }
                                        
                                        // Unsigned little-endian integer, loop count or zero for "forever"
                                        $loopData = fread( $fh, 2 );
@@ -118,6 +131,8 @@ class GIFMetadataExtractor {
                                        
                                        // Read out terminator byte
                                        fread( $fh, 1 );
+                               } else {
+                                       self::skipBlock( $fh );
                                }
                        } elseif ( $buf == self::$gif_term ) {
                                break;
@@ -128,8 +143,6 @@ class GIFMetadataExtractor {
                        }
                }
                
-               wfProfileOut( __METHOD__ );
-               
                return array(
                        'frameCount' => $frameCount,
                        'looped' => $isLooped,
@@ -168,4 +181,4 @@ class GIFMetadataExtractor {
                }
        }
 
-}
\ No newline at end of file
+}