<?php
error_reporting(E_ALL | E_STRICT);

define('__STEP_32'  , 3);
define('__FACTOR_32', 16);
define('__FORMAT_READ_32', 'I2');

define('__STEP_64'  , 7);
define('__FACTOR_64', 32);
define('__FORMAT_READ_64', 'N2');

// Default is 32-bit
$__factor = constant('__FACTOR_32');
$__format = constant('__FORMAT_READ_32');
$__step   = constant('__STEP_32');

if (PHP_INT_SIZE === 8) {
	// Use 64-bit
	$__factor = constant('__FACTOR_64');
	$__format = constant('__FORMAT_READ_64');
	$__step   = constant('__STEP_64');
}

$buffer = file_get_contents('test.data.bin' . ($__factor * 2)) or die('Please run write.php first!' . PHP_EOL);

assert(filesize('test.data.bin' . ($__factor * 2)) == strlen($buffer));
assert((strlen($buffer) % 8) == 0);

print 'Hash(' . strlen($buffer) . ')=' . md5($buffer) . PHP_EOL;

$decoded = '';
$i = 0;
for ($pos = 0; $pos < strlen($buffer); $pos += 8) {
	$part = substr($buffer, $pos, 8);
	assert(strlen($part) == 8);
	//print 'part='.md5($part).PHP_EOL;
	$unpacked = unpack($__format, $part);
	//print 'unpacked='.print_r($unpacked,true);
	$unpacked = $unpacked[1] << $__factor | $unpacked[2];

	//print 'unpacked=' . $unpacked . PHP_EOL;
	for ($i = 0; $i < $__step; $i++) {
		$factor = pow(256, ($__step - 1 - $i));
		//print __LINE__.':i=' . $i . ',factor=' . $factor . ',unpacked=' . $unpacked . PHP_EOL;
		$chr = ($unpacked / $factor);
		//print __LINE__.':i=' . $i . ',chr=' . $chr . PHP_EOL;

		if ($chr > 0) {
			$a = explode('.', $chr);
			$chr = $a[0];
			//print __LINE__.':i=' . $i . ',chr=' . $chr . ',unpacked=' . $unpacked . PHP_EOL;
			$unpacked -= ($chr * $factor);
			//print __LINE__.':i=' . $i . ',chr=' . $chr . ',unpacked=' . $unpacked . PHP_EOL;
		} else {
			$chr = $unpacked;
			$unpacked = 0;
		}

		//print 'chr=' . $chr . PHP_EOL;
		$decoded .= chr($chr);
	}
}

$decoded = gzuncompress($decoded);

print 'Writing ' . strlen($decoded) . ' bytes to output ...' . PHP_EOL;
file_put_contents('test.data.out' . ($__factor * 2), $decoded);