--- /dev/null
+<?php
+
+namespace Cdb\Writer;
+
+use Cdb\Exception;
+use Cdb\Util;
+use Cdb\Writer;
+
+/**
+ * This is a port of D.J. Bernstein's CDB to PHP. It's based on the copy that
+ * appears in PHP 5.3. Changes are:
+ * * Error returns replaced with exceptions
+ * * Exception thrown if sizes or offsets are between 2GB and 4GB
+ * * Some variables renamed
+ *
+ * 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
+ *
+ * @file
+ */
+
+/**
+ * CDB writer class
+ */
+class PHP extends Writer {
+ protected $hplist;
+
+ protected $numentries;
+
+ protected $pos;
+
+ /**
+ * @param string $fileName
+ */
+ public function __construct( $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->hplist = array();
+ $this->numentries = 0;
+ $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 ) {
+ if ( strval( $key ) === '' ) {
+ // DBA cross-check hack
+ return;
+ }
+ $this->addbegin( strlen( $key ), strlen( $value ) );
+ $this->write( $key );
+ $this->write( $value );
+ $this->addend( strlen( $key ), strlen( $value ), Util::hash( $key ) );
+ }
+
+ /**
+ * @throws Exception
+ */
+ public function close() {
+ $this->finish();
+ if ( isset( $this->handle ) ) {
+ 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.' );
+ }
+ unset( $this->handle );
+ }
+
+ /**
+ * @throws Exception
+ * @param string $buf
+ */
+ protected function write( $buf ) {
+ $len = fwrite( $this->handle, $buf );
+ if ( $len !== strlen( $buf ) ) {
+ $this->throwException( 'Error writing to CDB file "' . $this->tmpFileName . '".' );
+ }
+ }
+
+ /**
+ * @throws Exception
+ * @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;
+ }
+
+ /**
+ * @param int $keylen
+ * @param int $datalen
+ * @param int $h
+ */
+ protected function addend( $keylen, $datalen, $h ) {
+ $this->hplist[] = array(
+ 'h' => $h,
+ 'p' => $this->pos
+ );
+
+ $this->numentries++;
+ $this->posplus( 8 );
+ $this->posplus( $keylen );
+ $this->posplus( $datalen );
+ }
+
+ /**
+ * @throws Exception
+ * @param int $keylen
+ * @param int $datalen
+ */
+ protected function addbegin( $keylen, $datalen ) {
+ 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 . '".' );
+ }
+ $buf = pack( 'VV', $keylen, $datalen );
+ $this->write( $buf );
+ }
+
+ /**
+ * @throws Exception
+ */
+ protected function finish() {
+ // 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 = array();
+ $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.
+ $packedTables = array_fill( 0, $this->numentries, false );
+ 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();
+ for ( $u = 0; $u < $len; ++$u ) {
+ $hashtable[$u] = array( 'h' => 0, 'p' => 0 );
+ }
+
+ // Fill the hashtable, using the next empty slot if the hashed slot
+ // is taken.
+ for ( $u = 0; $u < $count; ++$u ) {
+ $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
+ 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( 8 );
+ }
+ }
+
+ // 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
+ * @throws Exception
+ */
+ protected function throwException( $msg ) {
+ if ( $this->handle ) {
+ fclose( $this->handle );
+ unlink( $this->tmpFileName );
+ }
+ throw new Exception( $msg );
+ }
+}
scripts.mit.edu / autoinstallsdev / mediawiki.git / blobdiff