Subversion Repositories cheapmusic

<?php

//

//  FPDI - Version 1.3.1

//

//    Copyright 2004-2009 Setasign - Jan Slabon

//

//  Licensed under the Apache License, Version 2.0 (the "License");

//  you may not use this file except in compliance with the License.

//  You may obtain a copy of the License at

//

//      http://www.apache.org/licenses/LICENSE-2.0

//

//  Unless required by applicable law or agreed to in writing, software

//  distributed under the License is distributed on an "AS IS" BASIS,

//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

//  See the License for the specific language governing permissions and

//  limitations under the License.

//

class FilterLZW {

    var $sTable = array();

    var $data = null;

    var $dataLength = 0;

    var $tIdx;

    var $bitsToGet = 9;

    var $bytePointer;

    var $bitPointer;

    var $nextData = 0;

    var $nextBits = 0;

    var $andTable = array(511, 1023, 2047, 4095);

    function error($msg) {

        die($msg);

    }

    /**

     * Method to decode LZW compressed data.

     *

     * @param string data    The compressed data.

     */

    function decode($data) {

        if($data[0] == 0x00 && $data[1] == 0x01) {

            $this->error('LZW flavour not supported.');

        }

        $this->initsTable();

        $this->data = $data;

        $this->dataLength = strlen($data);

        // Initialize pointers

        $this->bytePointer = 0;

        $this->bitPointer = 0;

        $this->nextData = 0;

        $this->nextBits = 0;

        $oldCode = 0;

        $string = '';

        $uncompData = '';

        while (($code = $this->getNextCode()) != 257) {

            if ($code == 256) {

                $this->initsTable();

                $code = $this->getNextCode();

                if ($code == 257) {

                    break;

                }

                $uncompData .= $this->sTable[$code];

                $oldCode = $code;

            } else {

                if ($code < $this->tIdx) {

                    $string = $this->sTable[$code];

                    $uncompData .= $string;

                    $this->addStringToTable($this->sTable[$oldCode], $string[0]);

                    $oldCode = $code;

                } else {

                    $string = $this->sTable[$oldCode];

                    $string = $string.$string[0];

                    $uncompData .= $string;

                    $this->addStringToTable($string);

                    $oldCode = $code;

                }

            }

        }

        return $uncompData;

    }

    /**

     * Initialize the string table.

     */

    function initsTable() {

        $this->sTable = array();

        for ($i = 0; $i < 256; $i++)

            $this->sTable[$i] = chr($i);

        $this->tIdx = 258;

        $this->bitsToGet = 9;

    }

    /**

     * Add a new string to the string table.

     */

    function addStringToTable ($oldString, $newString='') {

        $string = $oldString.$newString;

        // Add this new String to the table

        $this->sTable[$this->tIdx++] = $string;

        if ($this->tIdx == 511) {

            $this->bitsToGet = 10;

        } else if ($this->tIdx == 1023) {

            $this->bitsToGet = 11;

        } else if ($this->tIdx == 2047) {

            $this->bitsToGet = 12;

        }

    }

    // Returns the next 9, 10, 11 or 12 bits

    function getNextCode() {

        if ($this->bytePointer == $this->dataLength) {

            return 257;

        }

        $this->nextData = ($this->nextData << 8) | (ord($this->data[$this->bytePointer++]) & 0xff);

        $this->nextBits += 8;

        if ($this->nextBits < $this->bitsToGet) {

            $this->nextData = ($this->nextData << 8) | (ord($this->data[$this->bytePointer++]) & 0xff);

            $this->nextBits += 8;

        }

        $code = ($this->nextData >> ($this->nextBits - $this->bitsToGet)) & $this->andTable[$this->bitsToGet-9];

        $this->nextBits -= $this->bitsToGet;

        return $code;

    }

    function encode($in) {

        $this->error("LZW encoding not implemented.");

    }

}