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<?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 );
}
}
?>