Bzip2 İşlevleri

<?php
/**
 * @return bool
 * @param string $in
 * @param string $out
 * @desc compressing the file with the bzip2-extension
*/
function bzip2 ($in, $out)
{
    if (!file_exists ($in) || !is_readable ($in))
        return false;
    if ((!file_exists ($out) && !is_writeable (dirname ($out)) || (file_exists($out) && !is_writable($out)) ))
        return false;
    
    $in_file = fopen ($in, "rb");
    $out_file = bzopen ($out, "wb");
    
    while (!feof ($in_file)) {
        $buffer = fgets ($in_file, 4096);
         bzwrite ($out_file, $buffer, 4096);
    }

    fclose ($in_file);
    bzclose ($out_file);
    
    return true;
}

/**
 * @return bool
 * @param string $in
 * @param string $out
 * @desc uncompressing the file with the bzip2-extension
*/
function bunzip2 ($in, $out)
{
    if (!file_exists ($in) || !is_readable ($in))
        return false;
    if ((!file_exists ($out) && !is_writeable (dirname ($out)) || (file_exists($out) && !is_writable($out)) ))
        return false;

    $in_file = bzopen ($in, "rb");
    $out_file = fopen ($out, "wb");

    while ($buffer = bzread ($in_file, 4096)) {
        fwrite ($out_file, $buffer, 4096);
    }
 
    bzclose ($in_file);
    fclose ($out_file);
    
    return true;
}
?>

<?php/* * Reading a BZIP2 file can be tricky, and I never seen a complete example of * code that account for any possible failure that may happen accessing a file * in general, and decoding compressed data in this specific case. * The example that follows is my attempt to address this gap. * Some things that worth noting are: * - Encoding/decoding errors must be detected with bzerrno(). * - bzopen() may fail returning FALSE if the file cannot be created or read, *   but succeeds also if the file is not properly encoded. * - bzread() may fail returning FALSE if it fails reading from the source, but *   it returns the empty string on end of file and on encoding error. * - bzread() may still return corrupted data with no error whatsoever until the *   BZIP2 algo encounters the first hash code, so data retrieved cannot be *   trusted until the very end of the file has been reached. */// Safety first:error_reporting(-1);// On error, set $php_errormsg:ini_set("track_errors", "1");/** * Reads and displays on stdout the content of a BZIP2 compressed file with * full error detection. * @param string $fn Filename. * @return void */function displaysBZIP2File($fn){    echo "Reading $fn:\n";    $bz = @bzopen($fn, "r");    if( $bz === FALSE ){        echo "ERROR: bzopen() failed: $php_errormsg\n";        return;    }    $errno = bzerrno($bz);    if( $errno != 0 ){        // May detect "DATA_ERROR_MAGIC" (not a BZIP2 file), or "DATA_ERROR"        // (BZIP2 decoding error) and maybe others BZIP2 errors too.        echo "ERROR: bzopen(): BZIP2 decoding failed: ", bzerrstr($bz), "\n";        @bzclose($bz);        return;    }    while(! feof($bz) ) {        $s = bzread($bz, 100);        if( $s === FALSE ){            echo "ERROR: bzread() failed: $php_errormsg\n";            @bzclose($bz);            return;        }        $errno = bzerrno($bz);        if( $errno != 0 ){            // May detect "DATA_ERROR" (BZIP2 decoding error) and maybe others            // BZIP2 errors too.            echo "ERROR: bzread(): BZIP2 decoding failed: ", bzerrstr($bz), "\n";            @bzclose($bz);            return;        }        echo "read: ", var_export($s, true), "\n";    }    if( ! bzclose($bz) ){        echo "ERROR: bzclose() failed: $php_errormsg\n";    }}// Target file:$fn = "test.bz2";// Test 1: writes and read a good BZIP2 file:file_put_contents($fn, bzcompress("Content of the file."));displaysBZIP2File($fn); // works ok.// Test 2: invalid content, not a BZIP2 file:file_put_contents($fn, "This ia plain text file, no compression at all!");displaysBZIP2File($fn); // ERROR: bzread(): BZIP2 decoding failed: DATA_ERROR_MAGIC// Test 3: creates a corrupted BZIP2 file:$plain = str_repeat("Quite random string. ", 1000);$compressed = bzcompress($plain);$compressed_corrupted = $compressed;$compressed_corrupted[(int)(strlen($compressed)/2)] = 'X'; // put random char in middlefile_put_contents($fn, $compressed_corrupted);displaysBZIP2File($fn);// Only after some Kbytes of garbage, it tells:// ERROR: bzread(): BZIP2 decoding failed: DATA_ERROR// Safe coding against headache, ever.?>