File size: 7.54Kb
<?php
/*
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
::
:: GIFDecoder Version 2.0 by László Zsidi, http://gifs.hu
::
:: Created at 2007. 02. 01. '07.47.AM'
::
::
::
::
:: Try on-line GIFBuilder Form demo based on GIFDecoder.
::
:: http://phpclasses.gifs.hu/demos/GifBuilder/
::
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
*/
Class GIFDecoder
{
var $GIF_buffer = Array( );
var $GIF_arrays = Array( );
var $GIF_delays = Array( );
var $GIF_offset = Array( );
var $GIF_stream = "";
var $GIF_string = "";
var $GIF_bfseek = 0;
var $GIF_screen = Array( );
var $GIF_global = Array( );
var $GIF_sorted;
var $GIF_colorS;
var $GIF_colorC;
var $GIF_colorF;
/*
:::::::::::::::::::::::::::::::::::::::::::::::::::
::
:: GIFDecoder ( $GIF_pointer )
::
*/
function GIFDecoder( $GIF_pointer )
{
$this->GIF_stream = $GIF_pointer;
GIFDecoder::GIFGetByte( 6 ); // GIF89a
GIFDecoder::GIFGetByte( 7 ); // Logical Screen Descriptor
$this->GIF_screen = $this->GIF_buffer;
$this->GIF_colorF = $this->GIF_buffer[4] & 0x80 ? 1 : 0;
$this->GIF_sorted = $this->GIF_buffer[4] & 0x08 ? 1 : 0;
$this->GIF_colorC = $this->GIF_buffer[4] & 0x07;
$this->GIF_colorS = 2 << $this->GIF_colorC;
if ( $this->GIF_colorF == 1 ) {
GIFDecoder::GIFGetByte( 3 * $this->GIF_colorS );
$this->GIF_global = $this->GIF_buffer;
}
/*
*
* 05.06.2007.
* Made a little modification
*
*
- for ( $cycle = 1; $cycle; ) {
+ if ( GIFDecoder::GIFGetByte ( 1 ) ) {
- switch ( $this->GIF_buffer [ 0 ] ) {
- case 0x21:
- GIFDecoder::GIFReadExtensions ( );
- break;
- case 0x2C:
- GIFDecoder::GIFReadDescriptor ( );
- break;
- case 0x3B:
- $cycle = 0;
- break;
- }
- }
+ else {
+ $cycle = 0;
+ }
- }
*/
for ( $cycle = 1; $cycle; ) {
if ( GIFDecoder::GIFGetByte( 1 ) ) {
switch ( $this->GIF_buffer[0] ) {
case 0x21:
GIFDecoder::GIFReadExtensions();
break;
case 0x2C:
GIFDecoder::GIFReadDescriptor();
break;
case 0x3B:
$cycle = 0;
break;
}
} else {
$cycle = 0;
}
}
}
/*
:::::::::::::::::::::::::::::::::::::::::::::::::::
::
:: GIFReadExtension ( )
::
*/
function GIFReadExtensions( )
{
GIFDecoder::GIFGetByte( 1 );
for ( ;; ) {
GIFDecoder::GIFGetByte( 1 );
if ( ( $u = $this->GIF_buffer[0] ) == 0x00 ) {
break;
}
GIFDecoder::GIFGetByte( $u );
/*
* 07.05.2007.
* Implemented a new line for a new function
* to determine the originaly delays between
* frames.
*
*/
if ( $u == 4 ) {
$this->GIF_delays[] = ( $this->GIF_buffer[1] | $this->GIF_buffer[2] << 8 );
}
}
}
/*
:::::::::::::::::::::::::::::::::::::::::::::::::::
::
:: GIFReadExtension ( )
::
*/
function GIFReadDescriptor( )
{
$GIF_screen = Array( );
GIFDecoder::GIFGetByte( 9 );
$GIF_screen = $this->GIF_buffer;
/*
* 11.19.2007.
* Implemented a new line for a new function
* to determine the originaly XY offsets between
* frames.
*
*/
$this->GIF_offset[] = Array(
( $this->GIF_buffer[0] | $this->GIF_buffer[1] << 8 ),
( $this->GIF_buffer[2] | $this->GIF_buffer[3] << 8 )
);
$GIF_colorF = $this->GIF_buffer[8] & 0x80 ? 1 : 0;
if ( $GIF_colorF ) {
$GIF_code = $this->GIF_buffer[8] & 0x07;
$GIF_sort = $this->GIF_buffer[8] & 0x20 ? 1 : 0;
} else {
$GIF_code = $this->GIF_colorC;
$GIF_sort = $this->GIF_sorted;
}
$GIF_size = 2 << $GIF_code;
$this->GIF_screen[4] &= 0x70;
$this->GIF_screen[4] |= 0x80;
$this->GIF_screen[4] |= $GIF_code;
if ( $GIF_sort ) {
$this->GIF_screen[4] |= 0x08;
}
$this->GIF_string = "GIF87a";
GIFDecoder::GIFPutByte( $this->GIF_screen );
if ( $GIF_colorF == 1 ) {
GIFDecoder::GIFGetByte( 3 * $GIF_size );
GIFDecoder::GIFPutByte( $this->GIF_buffer );
} else {
GIFDecoder::GIFPutByte( $this->GIF_global );
}
$this->GIF_string .= chr( 0x2C );
$GIF_screen[8] &= 0x40;
GIFDecoder::GIFPutByte( $GIF_screen );
GIFDecoder::GIFGetByte( 1 );
GIFDecoder::GIFPutByte( $this->GIF_buffer );
for ( ;; ) {
GIFDecoder::GIFGetByte( 1 );
GIFDecoder::GIFPutByte( $this->GIF_buffer );
if ( ( $u = $this->GIF_buffer[0] ) == 0x00 ) {
break;
}
GIFDecoder::GIFGetByte( $u );
GIFDecoder::GIFPutByte( $this->GIF_buffer );
}
$this->GIF_string .= chr( 0x3B );
/*
*
* Add frames into $GIF_stream array...
*
*/
$this->GIF_arrays[] = $this->GIF_string;
}
/*
:::::::::::::::::::::::::::::::::::::::::::::::::::
::
:: GIFGetByte ( $len )
::
*/
/*
*
* 05.06.2007.
* Made a little modification
*
*
- function GIFGetByte ( $len ) {
- $this->GIF_buffer = Array ( );
-
- for ( $i = 0; $i < $len; $i++ ) {
+ if ( $this->GIF_bfseek > strlen ( $this->GIF_stream ) ) {
+ return 0;
+ }
- $this->GIF_buffer [ ] = ord ( $this->GIF_stream { $this->GIF_bfseek++ } );
- }
+ return 1;
- }
*/
function GIFGetByte( $len )
{
$this->GIF_buffer = Array( );
for ( $i = 0; $i < $len; $i++ ) {
if ( $this->GIF_bfseek > strlen( $this->GIF_stream ) ) {
return 0;
}
$this->GIF_buffer[] = ord( $this->GIF_stream{$this->GIF_bfseek++} );
}
return 1;
}
/*
:::::::::::::::::::::::::::::::::::::::::::::::::::
::
:: GIFPutByte ( $bytes )
::
*/
function GIFPutByte( $bytes )
{
for ( $i = 0; $i < count( $bytes ); $i++ ) {
$this->GIF_string .= chr( $bytes[$i] );
}
}
/*
:::::::::::::::::::::::::::::::::::::::::::::::::::
::
:: PUBLIC FUNCTIONS
::
::
:: GIFGetFrames ( )
::
*/
function GIFGetFrames( )
{
return ( $this->GIF_arrays );
}
/*
:::::::::::::::::::::::::::::::::::::::::::::::::::
::
:: GIFGetDelays ( )
::
*/
function GIFGetDelays( )
{
return ( $this->GIF_delays );
}
/*
:::::::::::::::::::::::::::::::::::::::::::::::::::
::
:: GIFGetOffset ( )
::
*/
function GIFGetOffset( )
{
return ( $this->GIF_offset );
}
}
?>