New file |
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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 (($data_length % 2) != 0) { |
// odd number of hexadecimal digits |
if ($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 characters |
if (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 characters |
if (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 byte |
for ($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 |
$prev_index = 0; |
// while we encounter EOD marker (257), read code_length bits |
while (($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 = $index; |
} else { |
// check if index exist in the dictionary |
if ($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 case |
if ($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 EOD |
break; |
} 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 error |
die('<strong>TCPDF_FILTERS ERROR: </strong>'.$msg); |
} |
|
} // END OF TCPDF_FILTERS CLASS |
|
//============================================================+ |
// END OF FILE |
//============================================================+ |