static $gif_extension_sep;
static $gif_term;
+ const VERSION = 1;
+
+ // Each sub-block is less than or equal to 255 bytes.
+ // Most of the time its 255 bytes, except for in XMP
+ // blocks, where it's usually between 32-127 bytes each.
+ const MAX_SUBBLOCKS = 262144; // 5mb divided by 20.
+
static function getMetadata( $filename ) {
self::$gif_frame_sep = pack( "C", ord("," ) );
self::$gif_extension_sep = pack( "C", ord("!" ) );
$frameCount = 0;
$duration = 0.0;
$isLooped = false;
-
+ $xmp = "";
+ $comment = array();
+
if ( !$filename ) {
throw new Exception( "No file name specified" );
} elseif ( !file_exists( $filename ) || is_dir( $filename ) ) {
if ($term != 0 ) {
throw new Exception( "Malformed Graphics Control Extension block" );
}
+ } elseif ($extension_code == 0xFE) {
+ // Comment block(s).
+ $data = '';
+
+ $data = self::readBlock( $fh );
+ if ( $data === "" ) {
+ throw new Exception( 'Read error, zero-length comment block' );
+ }
+
+ // The standard says this should be ASCII, however its unclear if
+ // thats true in practise. Check to see if its valid utf-8, if so
+ // assume its that, otherwise assume its iso-8859-1
+ $dataCopy = $data;
+ // quickIsNFCVerify has the side effect of replacing any invalid characters
+ UtfNormal::quickIsNFCVerify( $dataCopy );
+
+ if ( $dataCopy !== $data ) {
+ wfSuppressWarnings();
+ $data = iconv( 'ISO-8859-1', 'UTF-8', $data );
+ wfRestoreWarnings();
+ }
+
+ $commentCount = count( $comment );
+ if ( $commentCount === 0
+ || $comment[$commentCount-1] !== $data )
+ {
+ // Some applications repeat the same comment on each
+ // frame of an animated GIF image, so if this comment
+ // is identical to the last, only extract once.
+ $comment[] = $data;
+ }
} elseif ($extension_code == 0xFF) {
// Application extension (Netscape info about the animated gif)
+ // or XMP (or theoretically any other type of extension block)
$blockLength = fread( $fh, 1 );
$blockLength = unpack( 'C', $blockLength );
$blockLength = $blockLength[1];
$data = fread( $fh, $blockLength );
- // NETSCAPE2.0 (application name)
- if ($blockLength != 11 || $data != 'NETSCAPE2.0') {
+ if ($blockLength != 11 ) {
+ wfDebug( __METHOD__ . ' GIF application block with wrong length' );
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;
+ // NETSCAPE2.0 (application name for animated gif)
+ if ( $data == 'NETSCAPE2.0' ) {
+
+ $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 );
+ } elseif ( $data == 'XMP DataXMP' ) {
+ // application name for XMP data.
+ // see pg 18 of XMP spec part 3.
+
+ $xmp = self::readBlock( $fh, true );
+
+ if ( substr( $xmp, -257, 3 ) !== "\x01\xFF\xFE"
+ || substr( $xmp, -4 ) !== "\x03\x02\x01\x00" )
+ {
+ // this is just a sanity check.
+ throw new Exception( "XMP does not have magic trailer!" );
+ }
+
+ // strip out trailer.
+ $xmp = substr( $xmp, 0, -257 );
+
+ } else {
+ // unrecognized extension block
+ fseek( $fh, -($blockLength + 1), SEEK_CUR );
+ self::skipBlock( $fh );
+ continue;
}
-
- // Read out terminator byte
- fread( $fh, 1 );
} else {
self::skipBlock( $fh );
}
return array(
'frameCount' => $frameCount,
'looped' => $isLooped,
- 'duration' => $duration
+ 'duration' => $duration,
+ 'xmp' => $xmp,
+ 'comment' => $comment,
);
}
fread( $fh, $block_len );
}
}
+ /**
+ * Read a block. In the GIF format, a block is made up of
+ * several sub-blocks. Each sub block starts with one byte
+ * saying how long the sub-block is, followed by the sub-block.
+ * The entire block is terminated by a sub-block of length
+ * 0.
+ * @param $fh FileHandle
+ * @param $includeLengths Boolean Include the length bytes of the
+ * sub-blocks in the returned value. Normally this is false,
+ * except XMP is weird and does a hack where you need to keep
+ * these length bytes.
+ * @return The data.
+ */
+ static function readBlock( $fh, $includeLengths = false ) {
+ $data = '';
+ $subLength = fread( $fh, 1 );
+ $blocks = 0;
+
+ while( $subLength !== "\0" ) {
+ $blocks++;
+ if ( $blocks > self::MAX_SUBBLOCKS ) {
+ throw new Exception( "MAX_SUBBLOCKS exceeded (over $blocks sub-blocks)" );
+ }
+ if ( feof( $fh ) ) {
+ throw new Exception( "Read error: Unexpected EOF." );
+ }
+ if ( $includeLengths ) {
+ $data .= $subLength;
+ }
+
+ $data .= fread( $fh, ord( $subLength ) );
+ $subLength = fread( $fh, 1 );
+ }
+ return $data;
+ }
+
}
dépôts / lhc / web / wiklou.git / blobdiff