+++ /dev/null
-<?php
-/**
- * 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
- *
- * @file
- */
-
-/**
- * Common functions for readers and writers
- */
-class CdbFunctions {
- /**
- * Take a modulo of a signed integer as if it were an unsigned integer.
- * $b must be less than 0x40000000 and greater than 0
- */
- public static function unsignedMod( $a, $b ) {
- if ( $a & 0x80000000 ) {
- $m = ( $a & 0x7fffffff ) % $b + 2 * ( 0x40000000 % $b );
- return $m % $b;
- } else {
- return $a % $b;
- }
- }
-
- /**
- * Shift a signed integer right as if it were unsigned
- */
- public static function unsignedShiftRight( $a, $b ) {
- if ( $b == 0 ) {
- return $a;
- }
- if ( $a & 0x80000000 ) {
- return ( ( $a & 0x7fffffff ) >> $b ) | ( 0x40000000 >> ( $b - 1 ) );
- } else {
- return $a >> $b;
- }
- }
-
- /**
- * The CDB hash function.
- */
- public static function hash( $s ) {
- $h = 5381;
- for ( $i = 0; $i < strlen( $s ); $i++ ) {
- $h5 = ($h << 5) & 0xffffffff;
- // Do a 32-bit sum
- // Inlined here for speed
- $sum = ($h & 0x3fffffff) + ($h5 & 0x3fffffff);
- $h =
- (
- ( $sum & 0x40000000 ? 1 : 0 )
- + ( $h & 0x80000000 ? 2 : 0 )
- + ( $h & 0x40000000 ? 1 : 0 )
- + ( $h5 & 0x80000000 ? 2 : 0 )
- + ( $h5 & 0x40000000 ? 1 : 0 )
- ) << 30
- | ( $sum & 0x3fffffff );
- $h ^= ord( $s[$i] );
- $h &= 0xffffffff;
- }
- return $h;
- }
-}
-
-/**
- * CDB reader class
- */
-class CdbReader_PHP extends CdbReader {
- /** The file handle */
- var $handle;
-
- /* number of hash slots searched under this key */
- var $loop;
-
- /* initialized if loop is nonzero */
- var $khash;
-
- /* initialized if loop is nonzero */
- var $kpos;
-
- /* initialized if loop is nonzero */
- var $hpos;
-
- /* initialized if loop is nonzero */
- var $hslots;
-
- /* initialized if findNext() returns true */
- var $dpos;
-
- /* initialized if cdb_findnext() returns 1 */
- var $dlen;
-
- function __construct( $fileName ) {
- $this->handle = fopen( $fileName, 'rb' );
- if ( !$this->handle ) {
- throw new MWException( 'Unable to open CDB file "' . $fileName . '"' );
- }
- $this->findStart();
- }
-
- function close() {
- if( isset($this->handle) )
- fclose( $this->handle );
- unset( $this->handle );
- }
-
- public function get( $key ) {
- // strval is required
- if ( $this->find( strval( $key ) ) ) {
- return $this->read( $this->dlen, $this->dpos );
- } else {
- return false;
- }
- }
-
- protected function match( $key, $pos ) {
- $buf = $this->read( strlen( $key ), $pos );
- return $buf === $key;
- }
-
- protected function findStart() {
- $this->loop = 0;
- }
-
- protected function read( $length, $pos ) {
- if ( fseek( $this->handle, $pos ) == -1 ) {
- // This can easily happen if the internal pointers are incorrect
- throw new MWException( __METHOD__.': seek failed, file may be corrupted.' );
- }
-
- if ( $length == 0 ) {
- return '';
- }
-
- $buf = fread( $this->handle, $length );
- if ( $buf === false || strlen( $buf ) !== $length ) {
- throw new MWException( __METHOD__.': read from CDB file failed, file may be corrupted' );
- }
- return $buf;
- }
-
- /**
- * Unpack an unsigned integer and throw an exception if it needs more than 31 bits
- */
- protected function unpack31( $s ) {
- $data = unpack( 'V', $s );
- if ( $data[1] > 0x7fffffff ) {
- throw new MWException( __METHOD__.': error in CDB file, integer too big' );
- }
- return $data[1];
- }
-
- /**
- * Unpack a 32-bit signed integer
- */
- protected function unpackSigned( $s ) {
- $data = unpack( 'va/vb', $s );
- return $data['a'] | ( $data['b'] << 16 );
- }
-
- protected function findNext( $key ) {
- if ( !$this->loop ) {
- $u = CdbFunctions::hash( $key );
- $buf = $this->read( 8, ( $u << 3 ) & 2047 );
- $this->hslots = $this->unpack31( substr( $buf, 4 ) );
- if ( !$this->hslots ) {
- return false;
- }
- $this->hpos = $this->unpack31( substr( $buf, 0, 4 ) );
- $this->khash = $u;
- $u = CdbFunctions::unsignedShiftRight( $u, 8 );
- $u = CdbFunctions::unsignedMod( $u, $this->hslots );
- $u <<= 3;
- $this->kpos = $this->hpos + $u;
- }
-
- while ( $this->loop < $this->hslots ) {
- $buf = $this->read( 8, $this->kpos );
- $pos = $this->unpack31( substr( $buf, 4 ) );
- if ( !$pos ) {
- return false;
- }
- $this->loop += 1;
- $this->kpos += 8;
- if ( $this->kpos == $this->hpos + ( $this->hslots << 3 ) ) {
- $this->kpos = $this->hpos;
- }
- $u = $this->unpackSigned( substr( $buf, 0, 4 ) );
- if ( $u === $this->khash ) {
- $buf = $this->read( 8, $pos );
- $keyLen = $this->unpack31( substr( $buf, 0, 4 ) );
- if ( $keyLen == strlen( $key ) && $this->match( $key, $pos + 8 ) ) {
- // Found
- $this->dlen = $this->unpack31( substr( $buf, 4 ) );
- $this->dpos = $pos + 8 + $keyLen;
- return true;
- }
- }
- }
- return false;
- }
-
- protected function find( $key ) {
- $this->findStart();
- return $this->findNext( $key );
- }
-}
-
-/**
- * CDB writer class
- */
-class CdbWriter_PHP extends CdbWriter {
- var $handle, $realFileName, $tmpFileName;
-
- var $hplist;
- var $numEntries, $pos;
-
- function __construct( $fileName ) {
- $this->realFileName = $fileName;
- $this->tmpFileName = $fileName . '.tmp.' . mt_rand( 0, 0x7fffffff );
- $this->handle = fopen( $this->tmpFileName, 'wb' );
- if ( !$this->handle ) {
- throw new MWException( 'Unable to open CDB file for write "' . $fileName . '"' );
- }
- $this->hplist = array();
- $this->numentries = 0;
- $this->pos = 2048; // leaving space for the pointer array, 256 * 8
- if ( fseek( $this->handle, $this->pos ) == -1 ) {
- throw new MWException( __METHOD__.': fseek failed' );
- }
- }
-
- function __destruct() {
- if ( isset( $this->handle ) ) {
- $this->close();
- }
- }
-
- 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 ), CdbFunctions::hash( $key ) );
- }
-
- public function close() {
- $this->finish();
- if( isset($this->handle) )
- fclose( $this->handle );
- if ( wfIsWindows() && file_exists($this->realFileName) ) {
- unlink( $this->realFileName );
- }
- if ( !rename( $this->tmpFileName, $this->realFileName ) ) {
- throw new MWException( 'Unable to move the new CDB file into place.' );
- }
- unset( $this->handle );
- }
-
- protected function write( $buf ) {
- $len = fwrite( $this->handle, $buf );
- if ( $len !== strlen( $buf ) ) {
- throw new MWException( 'Error writing to CDB file.' );
- }
- }
-
- protected function posplus( $len ) {
- $newpos = $this->pos + $len;
- if ( $newpos > 0x7fffffff ) {
- throw new MWException( 'A value in the CDB file is too large' );
- }
- $this->pos = $newpos;
- }
-
- 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 );
- }
-
- protected function addbegin( $keylen, $datalen ) {
- if ( $keylen > 0x7fffffff ) {
- throw new MWException( __METHOD__.': key length too long' );
- }
- if ( $datalen > 0x7fffffff ) {
- throw new MWException( __METHOD__.': data length too long' );
- }
- $buf = pack( 'VV', $keylen, $datalen );
- $this->write( $buf );
- }
-
- 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 = CdbFunctions::unsignedMod(
- CdbFunctions::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,
- CdbFunctions::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 ) {
- throw new MWException( __METHOD__.': Error rewinding to start of file' );
- }
- $this->write( $final );
- }
-}
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