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PHP.php
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PHP.php
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<?php
/**
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*/
namespace Cdb\Writer;
use Cdb\Exception;
use Cdb\Util;
use Cdb\Writer;
/**
* CDB writer class
*
* This is a port of D.J. Bernstein's CDB to PHP. It's based on the copy that
* appears in PHP 5.3.
*/
class PHP extends Writer {
/**
* @var resource|false|null The file handle
*/
protected $handle;
/** @var int[][] */
protected $hplist = [];
/** @var int */
protected $numentries = 0;
/** @var int */
protected $pos;
/**
* Create the object and open the file.
*
* @param string $fileName
*/
public function __construct( string $fileName ) {
$this->realFileName = $fileName;
$this->tmpFileName = $fileName . '.tmp.' . mt_rand( 0, 0x7fffffff );
$this->handle = fopen( $this->tmpFileName, 'wb' );
if ( !$this->handle ) {
$this->throwException(
'Unable to open CDB file "' . $this->tmpFileName . '" for write.' );
}
$this->pos = 2048; // leaving space for the pointer array, 256 * 8
if ( fseek( $this->handle, $this->pos ) == -1 ) {
$this->throwException( 'fseek failed in file "' . $this->tmpFileName . '".' );
}
}
/**
* @param string $key
* @param string $value
*/
public function set( $key, $value ): void {
$key = (string)$key;
if ( $key === '' ) {
// DBA cross-check hack
return;
}
// Based on cdb_make_addbegin
$keylen = strlen( $key );
$datalen = strlen( $value );
if ( $keylen > 0x7fffffff ) {
$this->throwException( 'Key length too long in file "' . $this->tmpFileName . '".' );
}
if ( $datalen > 0x7fffffff ) {
$this->throwException( 'Data length too long in file "' . $this->tmpFileName . '".' );
}
$begin = pack( 'VV', $keylen, $datalen );
$this->write( $begin . $key . $value );
// Based on cdb_make_addend
$this->hplist[] = [
'h' => Util::hash( $key ),
'p' => $this->pos
];
$this->numentries++;
$this->posplus( 8 + $keylen + $datalen );
}
public function close(): void {
if ( $this->handle ) {
$this->finish();
fclose( $this->handle );
if ( $this->isWindows() && file_exists( $this->realFileName ) ) {
unlink( $this->realFileName );
}
if ( !rename( $this->tmpFileName, $this->realFileName ) ) {
$this->throwException( 'Unable to move the new CDB file into place.' );
}
}
$this->handle = null;
}
/**
* @param string $buf
*/
protected function write( $buf ): void {
$len = fwrite( $this->handle, $buf );
if ( $len !== strlen( $buf ) ) {
$this->throwException( 'Error writing to CDB file "' . $this->tmpFileName . '".' );
}
}
/**
* @param int $len
*/
protected function posplus( $len ) {
$newpos = $this->pos + $len;
if ( $newpos > 0x7fffffff ) {
$this->throwException(
'A value in the CDB file "' . $this->tmpFileName . '" is too large.' );
}
$this->pos = $newpos;
}
protected function finish(): void {
// Hack for DBA cross-check
$this->hplist = array_reverse( $this->hplist );
// Calculate the number of items that will be in each hashtable
$counts = array_fill( 0, 256, 0 );
foreach ( $this->hplist as $item ) {
++$counts[255 & $item['h']];
}
// Fill in $starts with the *end* indexes
$starts = [];
$pos = 0;
for ( $i = 0; $i < 256; ++$i ) {
$pos += $counts[$i];
$starts[$i] = $pos;
}
// Excessively clever and indulgent code to simultaneously fill $packedTables
// with the packed hashtables, and adjust the elements of $starts
// to actually point to the starts instead of the ends.
if ( $this->numentries > 0 ) {
$packedTables = array_fill( 0, $this->numentries, false );
} else {
// array_fill(): Number of elements must be positive
$packedTables = [];
}
foreach ( $this->hplist as $item ) {
$packedTables[--$starts[255 & $item['h']]] = $item;
}
$final = '';
for ( $i = 0; $i < 256; ++$i ) {
$count = $counts[$i];
// The size of the hashtable will be double the item count.
// The rest of the slots will be empty.
$len = $count + $count;
$final .= pack( 'VV', $this->pos, $len );
$hashtable = array_fill( 0, $len, [ 'h' => 0, 'p' => 0 ] );
// Fill the hashtable, using the next empty slot if the hashed slot
// is taken.
for ( $u = 0; $u < $count; ++$u ) {
// @phan-suppress-next-line PhanTypePossiblyInvalidDimOffset
$hp = $packedTables[$starts[$i] + $u];
$where = Util::unsignedMod(
Util::unsignedShiftRight( $hp['h'], 8 ), $len );
while ( $hashtable[$where]['p'] ) {
if ( ++$where == $len ) {
$where = 0;
}
}
$hashtable[$where] = $hp;
}
// Write the hashtable
$buf = '';
for ( $u = 0; $u < $len; ++$u ) {
$buf .= pack( 'vvV',
$hashtable[$u]['h'] & 0xffff,
Util::unsignedShiftRight( $hashtable[$u]['h'], 16 ),
$hashtable[$u]['p'] );
}
$this->write( $buf );
$this->posplus( strlen( $buf ) );
}
// Write the pointer array at the start of the file
rewind( $this->handle );
if ( ftell( $this->handle ) != 0 ) {
$this->throwException( 'Error rewinding to start of file "' . $this->tmpFileName . '".' );
}
$this->write( $final );
}
/**
* Clean up the temp file and throw an exception
*
* @param string $msg
* @return never
* @throws Exception
*/
protected function throwException( $msg ) {
if ( $this->handle ) {
fclose( $this->handle );
unlink( $this->tmpFileName );
}
throw new Exception( $msg );
}
}

File Metadata

Mime Type
text/x-php
Expires
Wed, Aug 19, 10:46 (3 w, 18 h ago)
Storage Engine
local-disk
Storage Format
Raw Data
Storage Handle
7e/07/83beccf253af677f82a1a17d3ec0
Default Alt Text
PHP.php (5 KB)

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