From 222b01f5169f1c7e69762e0e8904c24f78f71882 Mon Sep 17 00:00:00 2001
From: Pierre Schmitz <pierre@archlinux.de>
Date: Wed, 28 Jul 2010 11:52:48 +0200
Subject: update to MediaWiki 1.16.0

---
 includes/media/GIFMetadataExtractor.php | 175 ++++++++++++++++++++++++++++++++
 1 file changed, 175 insertions(+)
 create mode 100644 includes/media/GIFMetadataExtractor.php

(limited to 'includes/media/GIFMetadataExtractor.php')

diff --git a/includes/media/GIFMetadataExtractor.php b/includes/media/GIFMetadataExtractor.php
new file mode 100644
index 00000000..fac9012b
--- /dev/null
+++ b/includes/media/GIFMetadataExtractor.php
@@ -0,0 +1,175 @@
+<?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.
+  */
+
+class GIFMetadataExtractor {
+	static $gif_frame_sep;
+	static $gif_extension_sep;
+	static $gif_term;
+
+	static function getMetadata( $filename ) {
+		self::$gif_frame_sep = pack( "C", ord("," ) );
+		self::$gif_extension_sep = pack( "C", ord("!" ) );
+		self::$gif_term = pack( "C", ord(";" ) );
+		
+		$frameCount = 0;
+		$duration = 0.0;
+		$isLooped = false;
+		
+		if (!$filename)
+			throw new Exception( "No file name specified" );
+		elseif ( !file_exists($filename) || is_dir($filename) )
+			throw new Exception( "File $filename does not exist" );
+		
+		$fh = fopen( $filename, 'r' );
+		
+		if (!$fh)
+			throw new Exception( "Unable to open file $filename" );
+		
+		// Check for the GIF header
+		$buf = fread( $fh, 6 );
+		if ( !($buf == 'GIF87a' || $buf == 'GIF89a') ) {
+			throw new Exception( "Not a valid GIF file; header: $buf" );
+		}
+		
+		// Skip over width and height.
+		fread( $fh, 4 );
+		
+		// Read BPP
+		$buf = fread( $fh, 1 );
+		$bpp = self::decodeBPP( $buf );
+		
+		// Skip over background and aspect ratio
+		fread( $fh, 2 );
+		
+		// Skip over the GCT
+		self::readGCT( $fh, $bpp );
+		
+		while( !feof( $fh ) ) {
+			$buf = fread( $fh, 1 );
+			
+			if ($buf == self::$gif_frame_sep) {
+				// Found a frame
+				$frameCount++;
+				
+				## Skip bounding box
+				fread( $fh, 8 );
+				
+				## Read BPP
+				$buf = fread( $fh, 1 );
+				$bpp = self::decodeBPP( $buf );
+				
+				## Read GCT
+				self::readGCT( $fh, $bpp );
+				fread( $fh, 1 );
+				self::skipBlock( $fh );	
+			} elseif ( $buf == self::$gif_extension_sep ) {
+				$buf = fread( $fh, 1 );
+				$extension_code = unpack( 'C', $buf );
+				$extension_code = $extension_code[1];
+				
+				if ($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.
+					$delay = unpack( 'v', $buf );
+					$delay = $delay[1];
+					$duration += $delay * 0.01;
+					
+					fread( $fh, 1 ); // Transparent colour index
+					
+					$term = fread( $fh, 1 ); // Should be a terminator
+					$term = unpack( 'C', $term );
+					$term = $term[1];
+					if ($term != 0 )
+						throw new Exception( "Malformed Graphics Control Extension block" );
+				} elseif ($extension_code == 0xFF) {
+					// Application extension (Netscape info about the animated gif)
+					$blockLength = fread( $fh, 1 );
+					$blockLength = unpack( 'C', $blockLength );
+					$blockLength = $blockLength[1];
+					$data = fread( $fh, $blockLength );
+					
+					// NETSCAPE2.0 (application name)
+					if ($blockLength != 11 || $data != 'NETSCAPE2.0') {
+						fseek( $fh, -($blockLength + 1), SEEK_CUR );
+						self::skipBlock( $fh );
+						continue;
+					}
+					
+					$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 );
+					$loopData = unpack( 'v', $loopData );
+					$loopCount = $loopData[1];
+					
+					if ($loopCount != 1) {
+						$isLooped = true;
+					}
+					
+					// Read out terminator byte
+					fread( $fh, 1 );
+				} else {
+					self::skipBlock( $fh );
+				}
+			} elseif ( $buf == self::$gif_term ) {
+				break;
+			} else {
+				$byte = unpack( 'C', $buf );
+				$byte = $byte[1];
+				throw new Exception( "At position: ".ftell($fh). ", Unknown byte ".$byte );
+			}
+		}
+		
+		return array(
+			'frameCount' => $frameCount,
+			'looped' => $isLooped,
+			'duration' => $duration
+		);
+		
+	}
+	
+	static function readGCT( $fh, $bpp ) {
+		if ($bpp > 0) {
+			for( $i=1; $i<=pow(2,$bpp); ++$i ) {
+				fread( $fh, 3 );
+			}
+		}
+	}
+	
+	static function decodeBPP( $data ) {
+		$buf = unpack( 'C', $data );
+		$buf = $buf[1];
+		$bpp = ( $buf & 7 ) + 1;
+		$buf >>= 7;
+		
+		$have_map = $buf & 1;
+		
+		return $have_map ? $bpp : 0;
+	}
+	
+	static function skipBlock( $fh ) {
+		while ( !feof( $fh ) ) {
+			$buf = fread( $fh, 1 );
+			$block_len = unpack( 'C', $buf );
+			$block_len = $block_len[1];
+			if ($block_len == 0)
+				return;
+			fread( $fh, $block_len );
+		}
+	}
+
+}
-- 
cgit v1.2.2