c161c46d26
I searched for /\$(\S+) = (.+?\(.*?\);)\n.*?\$\1\[/, ignored everything involving isset(), unset() or array assigments, then skimmed through the remaining results and changed things where they made sense. These changes were not automated, so please review them. Change-Id: Ib37b4c66fc57648470f151ad412210b3629c2538
344 lines
9.2 KiB
PHP
344 lines
9.2 KiB
PHP
<?php
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/**
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* GIF frame counter.
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*
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* Originally written in Perl by Steve Sanbeg.
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* Ported to PHP by Andrew Garrett
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* Deliberately not using MWExceptions to avoid external dependencies, encouraging
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* redistribution.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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* http://www.gnu.org/copyleft/gpl.html
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*
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* @file
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* @ingroup Media
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*/
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/**
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* GIF frame counter.
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*
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* @ingroup Media
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*/
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class GIFMetadataExtractor {
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/** @var string */
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private static $gifFrameSep;
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/** @var string */
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private static $gifExtensionSep;
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/** @var string */
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private static $gifTerm;
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const VERSION = 1;
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// Each sub-block is less than or equal to 255 bytes.
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// Most of the time its 255 bytes, except for in XMP
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// blocks, where it's usually between 32-127 bytes each.
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const MAX_SUBBLOCKS = 262144; // 5mb divided by 20.
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/**
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* @throws Exception
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* @param string $filename
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* @return array
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*/
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static function getMetadata( $filename ) {
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self::$gifFrameSep = pack( "C", ord( "," ) );
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self::$gifExtensionSep = pack( "C", ord( "!" ) );
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self::$gifTerm = pack( "C", ord( ";" ) );
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$frameCount = 0;
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$duration = 0.0;
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$isLooped = false;
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$xmp = "";
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$comment = [];
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if ( !$filename ) {
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throw new Exception( "No file name specified" );
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} elseif ( !file_exists( $filename ) || is_dir( $filename ) ) {
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throw new Exception( "File $filename does not exist" );
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}
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$fh = fopen( $filename, 'rb' );
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if ( !$fh ) {
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throw new Exception( "Unable to open file $filename" );
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}
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// Check for the GIF header
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$buf = fread( $fh, 6 );
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if ( !( $buf == 'GIF87a' || $buf == 'GIF89a' ) ) {
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throw new Exception( "Not a valid GIF file; header: $buf" );
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}
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// Skip over width and height.
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fread( $fh, 4 );
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// Read BPP
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$buf = fread( $fh, 1 );
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$bpp = self::decodeBPP( $buf );
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// Skip over background and aspect ratio
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fread( $fh, 2 );
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// Skip over the GCT
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self::readGCT( $fh, $bpp );
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while ( !feof( $fh ) ) {
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$buf = fread( $fh, 1 );
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if ( $buf == self::$gifFrameSep ) {
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// Found a frame
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$frameCount++;
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# # Skip bounding box
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fread( $fh, 8 );
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# # Read BPP
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$buf = fread( $fh, 1 );
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$bpp = self::decodeBPP( $buf );
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# # Read GCT
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self::readGCT( $fh, $bpp );
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fread( $fh, 1 );
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self::skipBlock( $fh );
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} elseif ( $buf == self::$gifExtensionSep ) {
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$buf = fread( $fh, 1 );
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if ( strlen( $buf ) < 1 ) {
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throw new Exception( "Ran out of input" );
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}
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$extension_code = unpack( 'C', $buf )[1];
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if ( $extension_code == 0xF9 ) {
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// Graphics Control Extension.
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fread( $fh, 1 ); // Block size
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fread( $fh, 1 ); // Transparency, disposal method, user input
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$buf = fread( $fh, 2 ); // Delay, in hundredths of seconds.
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if ( strlen( $buf ) < 2 ) {
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throw new Exception( "Ran out of input" );
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}
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$delay = unpack( 'v', $buf )[1];
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$duration += $delay * 0.01;
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fread( $fh, 1 ); // Transparent colour index
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$term = fread( $fh, 1 ); // Should be a terminator
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if ( strlen( $term ) < 1 ) {
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throw new Exception( "Ran out of input" );
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}
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$term = unpack( 'C', $term )[1];
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if ( $term != 0 ) {
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throw new Exception( "Malformed Graphics Control Extension block" );
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}
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} elseif ( $extension_code == 0xFE ) {
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// Comment block(s).
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$data = self::readBlock( $fh );
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if ( $data === "" ) {
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throw new Exception( 'Read error, zero-length comment block' );
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}
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// The standard says this should be ASCII, however its unclear if
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// thats true in practise. Check to see if its valid utf-8, if so
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// assume its that, otherwise assume its windows-1252 (iso-8859-1)
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$dataCopy = $data;
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// quickIsNFCVerify has the side effect of replacing any invalid characters
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UtfNormal\Validator::quickIsNFCVerify( $dataCopy );
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if ( $dataCopy !== $data ) {
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MediaWiki\suppressWarnings();
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$data = iconv( 'windows-1252', 'UTF-8', $data );
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MediaWiki\restoreWarnings();
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}
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$commentCount = count( $comment );
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if ( $commentCount === 0
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|| $comment[$commentCount - 1] !== $data
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) {
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// Some applications repeat the same comment on each
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// frame of an animated GIF image, so if this comment
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// is identical to the last, only extract once.
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$comment[] = $data;
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}
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} elseif ( $extension_code == 0xFF ) {
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// Application extension (Netscape info about the animated gif)
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// or XMP (or theoretically any other type of extension block)
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$blockLength = fread( $fh, 1 );
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if ( strlen( $blockLength ) < 1 ) {
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throw new Exception( "Ran out of input" );
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}
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$blockLength = unpack( 'C', $blockLength )[1];
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$data = fread( $fh, $blockLength );
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if ( $blockLength != 11 ) {
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wfDebug( __METHOD__ . " GIF application block with wrong length\n" );
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fseek( $fh, -( $blockLength + 1 ), SEEK_CUR );
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self::skipBlock( $fh );
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continue;
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}
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// NETSCAPE2.0 (application name for animated gif)
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if ( $data == 'NETSCAPE2.0' ) {
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$data = fread( $fh, 2 ); // Block length and introduction, should be 03 01
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if ( $data != "\x03\x01" ) {
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throw new Exception( "Expected \x03\x01, got $data" );
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}
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// Unsigned little-endian integer, loop count or zero for "forever"
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$loopData = fread( $fh, 2 );
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if ( strlen( $loopData ) < 2 ) {
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throw new Exception( "Ran out of input" );
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}
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$loopCount = unpack( 'v', $loopData )[1];
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if ( $loopCount != 1 ) {
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$isLooped = true;
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}
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// Read out terminator byte
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fread( $fh, 1 );
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} elseif ( $data == 'XMP DataXMP' ) {
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// application name for XMP data.
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// see pg 18 of XMP spec part 3.
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$xmp = self::readBlock( $fh, true );
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if ( substr( $xmp, -257, 3 ) !== "\x01\xFF\xFE"
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|| substr( $xmp, -4 ) !== "\x03\x02\x01\x00"
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) {
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// this is just a sanity check.
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throw new Exception( "XMP does not have magic trailer!" );
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}
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// strip out trailer.
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$xmp = substr( $xmp, 0, -257 );
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} else {
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// unrecognized extension block
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fseek( $fh, -( $blockLength + 1 ), SEEK_CUR );
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self::skipBlock( $fh );
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continue;
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}
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} else {
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self::skipBlock( $fh );
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}
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} elseif ( $buf == self::$gifTerm ) {
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break;
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} else {
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if ( strlen( $buf ) < 1 ) {
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throw new Exception( "Ran out of input" );
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}
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$byte = unpack( 'C', $buf )[1];
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throw new Exception( "At position: " . ftell( $fh ) . ", Unknown byte " . $byte );
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}
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}
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return [
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'frameCount' => $frameCount,
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'looped' => $isLooped,
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'duration' => $duration,
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'xmp' => $xmp,
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'comment' => $comment,
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];
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}
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/**
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* @param resource $fh
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* @param int $bpp
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* @return void
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*/
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static function readGCT( $fh, $bpp ) {
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if ( $bpp > 0 ) {
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$max = pow( 2, $bpp );
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for ( $i = 1; $i <= $max; ++$i ) {
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fread( $fh, 3 );
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}
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}
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}
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/**
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* @param string $data
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* @throws Exception
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* @return int
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*/
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static function decodeBPP( $data ) {
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if ( strlen( $data ) < 1 ) {
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throw new Exception( "Ran out of input" );
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}
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$buf = unpack( 'C', $data )[1];
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$bpp = ( $buf & 7 ) + 1;
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$buf >>= 7;
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$have_map = $buf & 1;
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return $have_map ? $bpp : 0;
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}
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/**
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* @param resource $fh
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* @throws Exception
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*/
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static function skipBlock( $fh ) {
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while ( !feof( $fh ) ) {
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$buf = fread( $fh, 1 );
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if ( strlen( $buf ) < 1 ) {
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throw new Exception( "Ran out of input" );
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}
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$block_len = unpack( 'C', $buf )[1];
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if ( $block_len == 0 ) {
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return;
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}
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fread( $fh, $block_len );
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}
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}
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/**
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* Read a block. In the GIF format, a block is made up of
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* several sub-blocks. Each sub block starts with one byte
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* saying how long the sub-block is, followed by the sub-block.
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* The entire block is terminated by a sub-block of length
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* 0.
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* @param resource $fh File handle
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* @param bool $includeLengths Include the length bytes of the
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* sub-blocks in the returned value. Normally this is false,
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* except XMP is weird and does a hack where you need to keep
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* these length bytes.
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* @throws Exception
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* @return string The data.
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*/
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static function readBlock( $fh, $includeLengths = false ) {
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$data = '';
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$subLength = fread( $fh, 1 );
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$blocks = 0;
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while ( $subLength !== "\0" ) {
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$blocks++;
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if ( $blocks > self::MAX_SUBBLOCKS ) {
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throw new Exception( "MAX_SUBBLOCKS exceeded (over $blocks sub-blocks)" );
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}
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if ( feof( $fh ) ) {
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throw new Exception( "Read error: Unexpected EOF." );
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}
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if ( $includeLengths ) {
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$data .= $subLength;
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}
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$data .= fread( $fh, ord( $subLength ) );
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$subLength = fread( $fh, 1 );
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}
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return $data;
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}
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}
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