<?php
/**
* Memory-efficient integer storage class.
* Behaves like a normal array.
*
* This one uses: BINARY DATA
* and stores: 16 BIT integer.
*
*
* For example: 32768 entries use
* - 66520 bytes for HexArray
* - but 6817000 bytes for a PHP array()
* So it takes less than 1% of the memory size of a normal array.
*
*
*/
class WordArray IMPLEMENTS ArrayAccess {
var $data = "\0\0";
var $len = 2; // 2 bytes = 16 bit
var $pack = "S";
/**
* Initialize data.
*
* @param integer/string create either a fixed size empty array,
* or use source data (hexstring)
*/
function __construct($from=NULL) {
if (is_string($from)) {
$this->data = $from;
}
elseif (is_int($from)) {
$this->data = str_repeat("\0", $this->len * $from);
}
}
/**
* Compare array index against data size.
*
*/
function offsetExists ( $offset ) {
return (strlen($this->data) / $this->len) - 1 >= $offset;
}
/**
* Retrieve value.
*
*/
function offsetGet ( $offset ) {
return current(unpack($this->pack, substr($this->data, $offset * $this->len, $this->len)));
}
/**
* Update value.
*
*/
function offsetSet ( $offset , $value ) {
$bin = pack($this->pack, $value);# . "\0\0\0\0\0\0\0";
for ($i=0; $i<$this->len; $i++) {
$this->data[$offset * $this->len + $i] = $bin[$i];
}
}
/**
* Unsetting not supported.
*
*/
function offsetUnset ( $offset ) {
assert(false);
}
}
/**
* stores: 32 BIT integer
*
*
*/
class DWordArray extends WordArray {
var $len = 4; // 4 bytes = 32 bit
var $pack = "L";
}
/**
* stores: 64 BIT integer
*
*
*/
class QWordArray extends WordArray {
var $len = 8; // 8 bytes = 64 bit
var $pack = "L"; // Q not supported, workaround:
function offsetGet ( $offset ) {
return parent::offsetGet( $offset ) + parent::offsetGet( $offset + 0.5 ) << 32;
}
function offsetSet ( $offset, $value ) {
parent::offsetSet( $offset, $value & 0xFFFFFFFF );
parent::offsetSet( $offset + 0.5, $value >> 32 );
}
}
?>
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