<?php // +---------------------------------------------------------------------- // | ThinkPHP [ WE CAN DO IT JUST THINK IT ] // +---------------------------------------------------------------------- // | Copyright (c) 2006-2015 http://thinkphp.cn All rights reserved. // +---------------------------------------------------------------------- // | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 ) // +---------------------------------------------------------------------- // | Author: yunwuxin <448901948@qq.com> // +---------------------------------------------------------------------- namespace think\image\gif; class Decoder { public $GIF_buffer = []; public $GIF_arrays = []; public $GIF_delays = []; public $GIF_stream = ""; public $GIF_string = ""; public $GIF_bfseek = 0; public $GIF_screen = []; public $GIF_global = []; public $GIF_sorted; public $GIF_colorS; public $GIF_colorC; public $GIF_colorF; /* ::::::::::::::::::::::::::::::::::::::::::::::::::: :: :: GIFDecoder ( $GIF_pointer ) :: */ public function __construct($GIF_pointer) { $this->GIF_stream = $GIF_pointer; $this->getByte(6); // GIF89a $this->getByte(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 (1 == $this->GIF_colorF) { $this->getByte(3 * $this->GIF_colorS); $this->GIF_global = $this->GIF_buffer; } for ($cycle = 1; $cycle;) { if ($this->getByte(1)) { switch ($this->GIF_buffer[0]) { case 0x21: $this->readExtensions(); break; case 0x2C: $this->readDescriptor(); break; case 0x3B: $cycle = 0; break; } } else { $cycle = 0; } } } /* ::::::::::::::::::::::::::::::::::::::::::::::::::: :: :: GIFReadExtension ( ) :: */ public function readExtensions() { $this->getByte(1); for (; ;) { $this->getByte(1); if (($u = $this->GIF_buffer[0]) == 0x00) { break; } $this->getByte($u); /* * 07.05.2007. * Implemented a new line for a new function * to determine the originaly delays between * frames. * */ if (4 == $u) { $this->GIF_delays[] = ($this->GIF_buffer[1] | $this->GIF_buffer[2] << 8); } } } /* ::::::::::::::::::::::::::::::::::::::::::::::::::: :: :: GIFReadExtension ( ) :: */ public function readDescriptor() { $this->getByte(9); $GIF_screen = $this->GIF_buffer; $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"; $this->putByte($this->GIF_screen); if (1 == $GIF_colorF) { $this->getByte(3 * $GIF_size); $this->putByte($this->GIF_buffer); } else { $this->putByte($this->GIF_global); } $this->GIF_string .= chr(0x2C); $GIF_screen[8] &= 0x40; $this->putByte($GIF_screen); $this->getByte(1); $this->putByte($this->GIF_buffer); for (; ;) { $this->getByte(1); $this->putByte($this->GIF_buffer); if (($u = $this->GIF_buffer[0]) == 0x00) { break; } $this->getByte($u); $this->putByte($this->GIF_buffer); } $this->GIF_string .= chr(0x3B); /* Add frames into $GIF_stream array... */ $this->GIF_arrays[] = $this->GIF_string; } /* ::::::::::::::::::::::::::::::::::::::::::::::::::: :: :: GIFGetByte ( $len ) :: */ public function getByte($len) { $this->GIF_buffer = []; for ($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 ( $bytes ) :: */ public function putByte($bytes) { for ($i = 0; $i < count($bytes); $i++) { $this->GIF_string .= chr($bytes[$i]); } } /* ::::::::::::::::::::::::::::::::::::::::::::::::::: :: :: PUBLIC FUNCTIONS :: :: :: GIFGetFrames ( ) :: */ public function getFrames() { return ($this->GIF_arrays); } /* ::::::::::::::::::::::::::::::::::::::::::::::::::: :: :: GIFGetDelays ( ) :: */ public function getDelays() { return ($this->GIF_delays); } }