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Diffstat (limited to 'vendor/wikimedia/cdb/src/Writer/PHP.php')
-rw-r--r-- | vendor/wikimedia/cdb/src/Writer/PHP.php | 240 |
1 files changed, 240 insertions, 0 deletions
diff --git a/vendor/wikimedia/cdb/src/Writer/PHP.php b/vendor/wikimedia/cdb/src/Writer/PHP.php new file mode 100644 index 00000000..68c6b760 --- /dev/null +++ b/vendor/wikimedia/cdb/src/Writer/PHP.php @@ -0,0 +1,240 @@ +<?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 ); + } +} |