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<?php//============================================================+// File name : tcpdf_filters.php// Version : 1.0.000// Begin : 2011-05-23// Last Update : 2013-03-17// Author : Nicola Asuni - Tecnick.com LTD - www.tecnick.com - info@tecnick.com// License : GNU-LGPL v3 (http://www.gnu.org/copyleft/lesser.html)// -------------------------------------------------------------------// Copyright (C) 2011-2013 Nicola Asuni - Tecnick.com LTD//// This file is part of TCPDF software library.//// TCPDF is free software: you can redistribute it and/or modify it// under the terms of the GNU Lesser General Public License as// published by the Free Software Foundation, either version 3 of the// License, or (at your option) any later version.//// TCPDF is distributed in the hope that it will be useful, but// WITHOUT ANY WARRANTY; without even the implied warranty of// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.// See the GNU Lesser General Public License for more details.//// You should have received a copy of the License// along with TCPDF. If not, see// <http://www.tecnick.com/pagefiles/tcpdf/LICENSE.TXT>.//// See LICENSE.TXT file for more information.// -------------------------------------------------------------------//// Description : This is a PHP class for decoding common PDF filters (PDF 32000-2008 - 7.4 Filters).////============================================================+/*** @file* This is a PHP class for decoding common PDF filters (PDF 32000-2008 - 7.4 Filters).<br>* @package com.tecnick.tcpdf* @author Nicola Asuni* @version 1.0.000*//*** @class TCPDF_FILTERS* This is a PHP class for decoding common PDF filters (PDF 32000-2008 - 7.4 Filters).<br>* @package com.tecnick.tcpdf* @brief This is a PHP class for decoding common PDF filters.* @version 1.0.000* @author Nicola Asuni - info@tecnick.com*/class TCPDF_FILTERS {/*** Define a list of available filter decoders.* @private static*/private static $available_filters = array('ASCIIHexDecode', 'ASCII85Decode', 'LZWDecode', 'FlateDecode', 'RunLengthDecode');// -----------------------------------------------------------------------------/*** Get a list of available decoding filters.* @return (array) Array of available filter decoders.* @since 1.0.000 (2011-05-23)* @public static*/public static function getAvailableFilters() {return self::$available_filters;}/*** Decode data using the specified filter type.* @param $filter (string) Filter name.* @param $data (string) Data to decode.* @return Decoded data string.* @since 1.0.000 (2011-05-23)* @public static*/public static function decodeFilter($filter, $data) {switch ($filter) {case 'ASCIIHexDecode': {return self::decodeFilterASCIIHexDecode($data);break;}case 'ASCII85Decode': {return self::decodeFilterASCII85Decode($data);break;}case 'LZWDecode': {return self::decodeFilterLZWDecode($data);break;}case 'FlateDecode': {return self::decodeFilterFlateDecode($data);break;}case 'RunLengthDecode': {return self::decodeFilterRunLengthDecode($data);break;}case 'CCITTFaxDecode': {return self::decodeFilterCCITTFaxDecode($data);break;}case 'JBIG2Decode': {return self::decodeFilterJBIG2Decode($data);break;}case 'DCTDecode': {return self::decodeFilterDCTDecode($data);break;}case 'JPXDecode': {return self::decodeFilterJPXDecode($data);break;}case 'Crypt': {return self::decodeFilterCrypt($data);break;}default: {return self::decodeFilterStandard($data);break;}}}// --- FILTERS (PDF 32000-2008 - 7.4 Filters) ------------------------------/*** Standard* Default decoding filter (leaves data unchanged).* @param $data (string) Data to decode.* @return Decoded data string.* @since 1.0.000 (2011-05-23)* @public static*/public static function decodeFilterStandard($data) {return $data;}/*** ASCIIHexDecode* Decodes data encoded in an ASCII hexadecimal representation, reproducing the original binary data.* @param $data (string) Data to decode.* @return Decoded data string.* @since 1.0.000 (2011-05-23)* @public static*/public static function decodeFilterASCIIHexDecode($data) {// intialize string to return$decoded = '';// all white-space characters shall be ignored$data = preg_replace('/[\s]/', '', $data);// check for EOD character: GREATER-THAN SIGN (3Eh)$eod = strpos($data, '>');if ($eod !== false) {// remove EOD and extra data (if any)$data = substr($data, 0, $eod);$eod = true;}// get data length$data_length = strlen($data);if (($data_length % 2) != 0) {// odd number of hexadecimal digitsif ($eod) {// EOD shall behave as if a 0 (zero) followed the last digit$data = substr($data, 0, -1).'0'.substr($data, -1);} else {self::Error('decodeASCIIHex: invalid code');}}// check for invalid charactersif (preg_match('/[^a-fA-F\d]/', $data) > 0) {self::Error('decodeASCIIHex: invalid code');}// get one byte of binary data for each pair of ASCII hexadecimal digits$decoded = pack('H*', $data);return $decoded;}/*** ASCII85Decode* Decodes data encoded in an ASCII base-85 representation, reproducing the original binary data.* @param $data (string) Data to decode.* @return Decoded data string.* @since 1.0.000 (2011-05-23)* @public static*/public static function decodeFilterASCII85Decode($data) {// intialize string to return$decoded = '';// all white-space characters shall be ignored$data = preg_replace('/[\s]/', '', $data);// remove start sequence 2-character sequence <~ (3Ch)(7Eh)if (strpos($data, '<~') !== false) {// remove EOD and extra data (if any)$data = substr($data, 2);}// check for EOD: 2-character sequence ~> (7Eh)(3Eh)$eod = strpos($data, '~>');if ($eod !== false) {// remove EOD and extra data (if any)$data = substr($data, 0, $eod);}// data length$data_length = strlen($data);// check for invalid charactersif (preg_match('/[^\x21-\x75,\x74]/', $data) > 0) {self::Error('decodeASCII85: invalid code');}// z sequence$zseq = chr(0).chr(0).chr(0).chr(0);// position inside a group of 4 bytes (0-3)$group_pos = 0;$tuple = 0;$pow85 = array((85*85*85*85), (85*85*85), (85*85), 85, 1);$last_pos = ($data_length - 1);// for each bytefor ($i = 0; $i < $data_length; ++$i) {// get char value$char = ord($data[$i]);if ($char == 122) { // 'z'if ($group_pos == 0) {$decoded .= $zseq;} else {self::Error('decodeASCII85: invalid code');}} else {// the value represented by a group of 5 characters should never be greater than 2^32 - 1$tuple += (($char - 33) * $pow85[$group_pos]);if ($group_pos == 4) {$decoded .= chr($tuple >> 24).chr($tuple >> 16).chr($tuple >> 8).chr($tuple);$tuple = 0;$group_pos = 0;} else {++$group_pos;}}}if ($group_pos > 1) {$tuple += $pow85[($group_pos - 1)];}// last tuple (if any)switch ($group_pos) {case 4: {$decoded .= chr($tuple >> 24).chr($tuple >> 16).chr($tuple >> 8);break;}case 3: {$decoded .= chr($tuple >> 24).chr($tuple >> 16);break;}case 2: {$decoded .= chr($tuple >> 24);break;}case 1: {self::Error('decodeASCII85: invalid code');break;}}return $decoded;}/*** LZWDecode* Decompresses data encoded using the LZW (Lempel-Ziv-Welch) adaptive compression method, reproducing the original text or binary data.* @param $data (string) Data to decode.* @return Decoded data string.* @since 1.0.000 (2011-05-23)* @public static*/public static function decodeFilterLZWDecode($data) {// intialize string to return$decoded = '';// data length$data_length = strlen($data);// convert string to binary string$bitstring = '';for ($i = 0; $i < $data_length; ++$i) {$bitstring .= sprintf('%08b', ord($data{$i}));}// get the number of bits$data_length = strlen($bitstring);// initialize code length in bits$bitlen = 9;// initialize dictionary index$dix = 258;// initialize the dictionary (with the first 256 entries).$dictionary = array();for ($i = 0; $i < 256; ++$i) {$dictionary[$i] = chr($i);}// previous val$prev_index = 0;// while we encounter EOD marker (257), read code_length bitswhile (($data_length > 0) AND (($index = bindec(substr($bitstring, 0, $bitlen))) != 257)) {// remove read bits from string$bitstring = substr($bitstring, $bitlen);// update number of bits$data_length -= $bitlen;if ($index == 256) { // clear-table marker// reset code length in bits$bitlen = 9;// reset dictionary index$dix = 258;$prev_index = 256;// reset the dictionary (with the first 256 entries).$dictionary = array();for ($i = 0; $i < 256; ++$i) {$dictionary[$i] = chr($i);}} elseif ($prev_index == 256) {// first entry$decoded .= $dictionary[$index];$prev_index = $index;} else {// check if index exist in the dictionaryif ($index < $dix) {// index exist on dictionary$decoded .= $dictionary[$index];$dic_val = $dictionary[$prev_index].$dictionary[$index]{0};// store current index$prev_index = $index;} else {// index do not exist on dictionary$dic_val = $dictionary[$prev_index].$dictionary[$prev_index]{0};$decoded .= $dic_val;}// update dictionary$dictionary[$dix] = $dic_val;++$dix;// change bit length by caseif ($dix == 2047) {$bitlen = 12;} elseif ($dix == 1023) {$bitlen = 11;} elseif ($dix == 511) {$bitlen = 10;}}}return $decoded;}/*** FlateDecode* Decompresses data encoded using the zlib/deflate compression method, reproducing the original text or binary data.* @param $data (string) Data to decode.* @return Decoded data string.* @since 1.0.000 (2011-05-23)* @public static*/public static function decodeFilterFlateDecode($data) {// intialize string to return$decoded = gzuncompress($data);if ($decoded === false) {self::Error('decodeFlate: invalid code');}return $decoded;}/*** RunLengthDecode* Decompresses data encoded using a byte-oriented run-length encoding algorithm.* @param $data (string) Data to decode.* @since 1.0.000 (2011-05-23)* @public static*/public static function decodeFilterRunLengthDecode($data) {// intialize string to return$decoded = '';// data length$data_length = strlen($data);$i = 0;while($i < $data_length) {// get current byte value$byte = ord($data{$i});if ($byte == 128) {// a length value of 128 denote EODbreak;} elseif ($byte < 128) {// if the length byte is in the range 0 to 127// the following length + 1 (1 to 128) bytes shall be copied literally during decompression$decoded .= substr($data, ($i + 1), ($byte + 1));// move to next block$i += ($byte + 2);} else {// if length is in the range 129 to 255,// the following single byte shall be copied 257 - length (2 to 128) times during decompression$decoded .= str_repeat($data{($i + 1)}, (257 - $byte));// move to next block$i += 2;}}return $decoded;}/*** CCITTFaxDecode (NOT IMPLEMETED)* Decompresses data encoded using the CCITT facsimile standard, reproducing the original data (typically monochrome image data at 1 bit per pixel).* @param $data (string) Data to decode.* @return Decoded data string.* @since 1.0.000 (2011-05-23)* @public static*/public static function decodeFilterCCITTFaxDecode($data) {return $data;}/*** JBIG2Decode (NOT IMPLEMETED)* Decompresses data encoded using the JBIG2 standard, reproducing the original monochrome (1 bit per pixel) image data (or an approximation of that data).* @param $data (string) Data to decode.* @return Decoded data string.* @since 1.0.000 (2011-05-23)* @public static*/public static function decodeFilterJBIG2Decode($data) {return $data;}/*** DCTDecode (NOT IMPLEMETED)* Decompresses data encoded using a DCT (discrete cosine transform) technique based on the JPEG standard, reproducing image sample data that approximates the original data.* @param $data (string) Data to decode.* @return Decoded data string.* @since 1.0.000 (2011-05-23)* @public static*/public static function decodeFilterDCTDecode($data) {return $data;}/*** JPXDecode (NOT IMPLEMETED)* Decompresses data encoded using the wavelet-based JPEG2000 standard, reproducing the original image data.* @param $data (string) Data to decode.* @return Decoded data string.* @since 1.0.000 (2011-05-23)* @public static*/public static function decodeFilterJPXDecode($data) {return $data;}/*** Crypt (NOT IMPLEMETED)* Decrypts data encrypted by a security handler, reproducing the data as it was before encryption.* @param $data (string) Data to decode.* @return Decoded data string.* @since 1.0.000 (2011-05-23)* @public static*/public static function decodeFilterCrypt($data) {return $data;}// --- END FILTERS SECTION -------------------------------------------------/*** This method is automatically called in case of fatal error; it simply outputs the message and halts the execution.* @param $msg (string) The error message* @since 1.0.000 (2011-05-23)* @public static*/public static function Error($msg) {// exit program and print errordie('<strong>TCPDF_FILTERS ERROR: </strong>'.$msg);}} // END OF TCPDF_FILTERS CLASS//============================================================+// END OF FILE//============================================================+