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@kaja47 kaja47/IntArray.php
Last active Dec 18, 2015

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Unboxed int array in PHP
<?php
// advanced bit-twiddling
abstract class AbstractIntArray {
protected $length;
protected $data;
protected $typeSize;
function __construct($length) {
$this->length = $length;
$this->data = str_repeat("\0", $length * $this->typeSize);
}
protected function checkIndex($idx) {
if (!is_int($idx))
throw new \InvalidArgumentException("index must be integer value");
if ($idx < 0 || $idx >= $this->length)
throw new \OutOfRangeException("index out of range");
}
protected function checkValue($val) {
if (!is_int($val))
throw new \InvalidArgumentException("Value must be integer.");
}
function getData() {
return $this->data;
}
}
/** store unsigned bytes */
final class ByteArray extends AbstractIntArray {
protected $typeSize = 1;
function get($idx) {
$this->checkIndex($idx);
return ord($this->data[$idx]);
}
function put($idx, $val) {
$this->checkIndex($idx);
$this->checkValue($val);
if ($val < 0 || $val > 255)
throw new \OutOfRangeException();
$this->data[$idx] = chr($val);
}
}
final class BitSet extends AbstractIntArray {
protected $length;
private $byteArray;
function __construct($length) {
$this->length = $length;
$this->byteArray = new ByteArray(ceil($length / 8));
}
function get($idx) {
$this->checkIndex($idx);
$byteIdx = (int) ($idx / 8);
$bitIdx = $idx % 8;
$byte = $this->byteArray->get($byteIdx);
return (($byte >> $bitIdx) & 1) === 1;
}
function put($idx, $val) {
$this->checkIndex($idx);
if (!is_bool($val))
throw new \OutOfRangeException();
$byteIdx = (int) ($idx / 8);
$bitIdx = $idx % 8;
$byte = $this->byteArray->get($byteIdx);
if ($val) {
$byte |= (1 << $bitIdx);
} else {
$byte &= (0 << $bitIdx);
}
$this->byteArray->put($byteIdx, $byte);
}
function getData() {
return $this->byteArray->getData();
}
}
final class Int32Array extends AbstractIntArray {
protected $typeSize = 4;
function get($idx) {
$this->checkIndex($idx);
$bytes = substr($this->data, $idx * 4, 4);
$res = unpack('V', $bytes);
return $res[1];
}
function put($idx, $val) {
$this->checkIndex($idx);
$this->checkValue($val);
$bytes = pack('V', $val);
$base = $idx * 4;
for ($i = 0; $i < 4; $i++) {
$this->data[$base + $i] = $bytes[$i];
}
}
}
final class Int64Array extends AbstractIntArray {
protected $typeSize = 8;
function get($idx) {
$this->checkIndex($idx);
$bytes = substr($this->data, $idx * 8, 8);
list(, $a, $b) = unpack('V2', $bytes);
return ($a << 32) + $b;
}
function put($idx, $val) {
$this->checkIndex($idx);
$this->checkValue($val);
$a = $val >> 32;
$b = $val & 0xffffffff;
$bytes = pack('VV', $a, $b);
$base = $idx * 8;
for ($i = 0; $i < 8; $i++) {
$this->data[$base + $i] = $bytes[$i];
}
}
}
@kaja47

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commented Jun 4, 2013

Array with 1000000 integers:

PHP 5.3 array: 129.00MB
PHP 5.5 array:  96.00MB
Int32Array:      4.25MB

Iterating through 1000000 element array:

PHP 5.5 array:  330ms
Int32Array:    2400ms
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