123 lines
2.7 KiB
PHP
123 lines
2.7 KiB
PHP
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<?php
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/**
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* Classes, which help reading streams of data from files.
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* Based on the classes from Danilo Segan <danilo@kvota.net>
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*
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* @version $Id: streams.php 33 2009-02-16 09:33:39Z nbachiyski $
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* @package pomo
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* @subpackage streams
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*/
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/**
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* Provides file-like methods for manipulating a string instead
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* of a physical file.
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*/
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class POMO_StringReader {
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var $_pos;
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var $_str;
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function POMO_StringReader($str = '') {
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$this->_str = $str;
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$this->_pos = 0;
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}
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function read($bytes) {
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$data = substr($this->_str, $this->_pos, $bytes);
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$this->_pos += $bytes;
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if (strlen($this->_str)<$this->_pos)
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$this->_pos = strlen($this->_str);
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return $data;
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}
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function seekto($pos) {
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$this->_pos = $pos;
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if (strlen($this->_str)<$this->_pos)
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$this->_pos = strlen($this->_str);
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return $this->_pos;
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}
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function pos() {
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return $this->_pos;
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}
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function length() {
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return strlen($this->_str);
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}
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}
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/**
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* Reads the contents of the file in the beginning.
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*/
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class POMO_CachedFileReader extends POMO_StringReader {
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function POMO_CachedFileReader($filename) {
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$this->_str = file_get_contents($filename);
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if (false === $this->_str)
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return false;
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$this->pos = 0;
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}
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}
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/**
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* Allows reading integers from a file.
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*/
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class POMO_CachedIntFileReader extends POMO_CachedFileReader {
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var $endian = 'little';
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/**
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* Opens a file and caches it.
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*
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* @param $filename string name of the file to be opened
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* @param $endian string endianness of the words in the file, allowed
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* values are 'little' or 'big'. Default value is 'little'
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*/
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function POMO_CachedIntFileReader($filename, $endian = 'little') {
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$this->endian = $endian;
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parent::POMO_CachedFileReader($filename);
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}
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/**
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* Sets the endianness of the file.
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*
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* @param $endian string 'big' or 'little'
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*/
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function setEndian($endian) {
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$this->endian = $endian;
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}
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/**
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* Reads a 32bit Integer from the Stream
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*
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* @return mixed The integer, corresponding to the next 32 bits from
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* the stream of false if there are not enough bytes or on error
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*/
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function readint32() {
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$bytes = $this->read(4);
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if (4 != strlen($bytes))
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return false;
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$endian_letter = ('big' == $this->endian)? 'N' : 'V';
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$int = unpack($endian_letter, $bytes);
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return array_shift($int);
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}
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/**
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* Reads an array of 32-bit Integers from the Stream
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*
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* @param integer count How many elements should be read
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* @return mixed Array of integers or false if there isn't
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* enough data or on error
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*/
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function readint32array($count) {
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$bytes = $this->read(4 * $count);
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if (4*$count != strlen($bytes))
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return false;
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$endian_letter = ('big' == $this->endian)? 'N' : 'V';
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return unpack($endian_letter.$count, $bytes);
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}
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}
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?>
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