<?php

/**

 * Zend Framework

 *

 * LICENSE

 *

 * This source file is subject to the new BSD license that is bundled

 * with this package in the file LICENSE.txt.

 * It is also available through the world-wide-web at this URL:

 * http://framework.zend.com/license/new-bsd

 * If you did not receive a copy of the license and are unable to

 * obtain it through the world-wide-web, please send an email

 * to license@zend.com so we can send you a copy immediately.

 *

 * @category   Zend

 * @package    Zend_Search_Lucene

 * @subpackage Index

 * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 * @version    $Id: DictionaryLoader.php 20096 2010-01-06 02:05:09Z bkarwin $

 */

/**

 * Dictionary loader

 *

 * It's a dummy class which is created to encapsulate non-good structured code.

 * Manual "method inlining" is performed to increase dictionary index loading operation

 * which is major bottelneck for search performance.

 *

 *

 * @category   Zend

 * @package    Zend_Search_Lucene

 * @subpackage Index

 * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 */

class Zend_Search_Lucene_Index_DictionaryLoader

{

    /**

     * Dictionary index loader.

     *

     * It takes a string which is actually <segment_name>.tii index file data and

     * returns two arrays - term and tremInfo lists.

     *

     * See Zend_Search_Lucene_Index_SegmintInfo class for details

     *

     * @param string $data

     * @return array

     * @throws Zend_Search_Lucene_Exception

     */

    public static function load($data)

    {

        $termDictionary = array();

        $termInfos      = array();

        $pos = 0;

        // $tiVersion = $tiiFile->readInt();

        $tiVersion = ord($data[0]) << 24 | ord($data[1]) << 16 | ord($data[2]) << 8  | ord($data[3]);

        $pos += 4;

        if ($tiVersion != (int)0xFFFFFFFE /* pre-2.1 format */ &&

            $tiVersion != (int)0xFFFFFFFD /* 2.1+ format    */) {

                require_once 'Zend/Search/Lucene/Exception.php';

                throw new Zend_Search_Lucene_Exception('Wrong TermInfoIndexFile file format');

        }

        // $indexTermCount = $tiiFile->readLong();

        if (PHP_INT_SIZE > 4) {

            $indexTermCount = ord($data[$pos]) << 56  |

                              ord($data[$pos+1]) << 48  |

                              ord($data[$pos+2]) << 40  |

                              ord($data[$pos+3]) << 32  |

                              ord($data[$pos+4]) << 24  |

                              ord($data[$pos+5]) << 16  |

                              ord($data[$pos+6]) << 8   |

                              ord($data[$pos+7]);

        } else {

            if ((ord($data[$pos])            != 0) ||

                (ord($data[$pos+1])          != 0) ||

                (ord($data[$pos+2])          != 0) ||

                (ord($data[$pos+3])          != 0) ||

                ((ord($data[$pos+4]) & 0x80) != 0)) {

                    require_once 'Zend/Search/Lucene/Exception.php';

                    throw new Zend_Search_Lucene_Exception('Largest supported segment size (for 32-bit mode) is 2Gb');

                 }

            $indexTermCount = ord($data[$pos+4]) << 24  |

                              ord($data[$pos+5]) << 16  |

                              ord($data[$pos+6]) << 8   |

                              ord($data[$pos+7]);

        }

        $pos += 8;

        //                  $tiiFile->readInt();  // IndexInterval

        $pos += 4;

        // $skipInterval   = $tiiFile->readInt();

        $skipInterval = ord($data[$pos]) << 24 | ord($data[$pos+1]) << 16 | ord($data[$pos+2]) << 8  | ord($data[$pos+3]);

        $pos += 4;

        if ($indexTermCount < 1) {

            require_once 'Zend/Search/Lucene/Exception.php';

            throw new Zend_Search_Lucene_Exception('Wrong number of terms in a term dictionary index');

        }

        if ($tiVersion == (int)0xFFFFFFFD /* 2.1+ format */) {

            /* Skip MaxSkipLevels value */

            $pos += 4;

        }

        $prevTerm     = '';

        $freqPointer  =  0;

        $proxPointer  =  0;

        $indexPointer =  0;

        for ($count = 0; $count < $indexTermCount; $count++) {

            //$termPrefixLength = $tiiFile->readVInt();

            $nbyte = ord($data[$pos++]);

            $termPrefixLength = $nbyte & 0x7F;

            for ($shift=7; ($nbyte & 0x80) != 0; $shift += 7) {

                $nbyte = ord($data[$pos++]);

                $termPrefixLength |= ($nbyte & 0x7F) << $shift;

            }

            // $termSuffix       = $tiiFile->readString();

            $nbyte = ord($data[$pos++]);

            $len = $nbyte & 0x7F;

            for ($shift=7; ($nbyte & 0x80) != 0; $shift += 7) {

                $nbyte = ord($data[$pos++]);

                $len |= ($nbyte & 0x7F) << $shift;

            }

            if ($len == 0) {

                $termSuffix = '';

            } else {

                $termSuffix = substr($data, $pos, $len);

                $pos += $len;

                for ($count1 = 0; $count1 < $len; $count1++ ) {

                    if (( ord($termSuffix[$count1]) & 0xC0 ) == 0xC0) {

                        $addBytes = 1;

                        if (ord($termSuffix[$count1]) & 0x20 ) {

                            $addBytes++;

                            // Never used for Java Lucene created index.

                            // Java2 doesn't encode strings in four bytes

                            if (ord($termSuffix[$count1]) & 0x10 ) {

                                $addBytes++;

                            }

                        }

                        $termSuffix .= substr($data, $pos, $addBytes);

                        $pos += $addBytes;

                        $len += $addBytes;

                        // Check for null character. Java2 encodes null character

                        // in two bytes.

                        if (ord($termSuffix[$count1]) == 0xC0 &&

                            ord($termSuffix[$count1+1]) == 0x80   ) {

                            $termSuffix[$count1] = 0;

                            $termSuffix = substr($termSuffix,0,$count1+1)

                                        . substr($termSuffix,$count1+2);

                        }

                        $count1 += $addBytes;

                    }

                }

            }

            // $termValue        = Zend_Search_Lucene_Index_Term::getPrefix($prevTerm, $termPrefixLength) . $termSuffix;

            $pb = 0; $pc = 0;

            while ($pb < strlen($prevTerm)  &&  $pc < $termPrefixLength) {

                $charBytes = 1;

                if ((ord($prevTerm[$pb]) & 0xC0) == 0xC0) {

                    $charBytes++;

                    if (ord($prevTerm[$pb]) & 0x20 ) {

                        $charBytes++;

                        if (ord($prevTerm[$pb]) & 0x10 ) {

                            $charBytes++;

                        }

                    }

                }

                if ($pb + $charBytes > strlen($data)) {

                    // wrong character

                    break;

                }

                $pc++;

                $pb += $charBytes;

            }

            $termValue = substr($prevTerm, 0, $pb) . $termSuffix;

            // $termFieldNum     = $tiiFile->readVInt();

            $nbyte = ord($data[$pos++]);

            $termFieldNum = $nbyte & 0x7F;

            for ($shift=7; ($nbyte & 0x80) != 0; $shift += 7) {

                $nbyte = ord($data[$pos++]);

                $termFieldNum |= ($nbyte & 0x7F) << $shift;

            }

            // $docFreq          = $tiiFile->readVInt();

            $nbyte = ord($data[$pos++]);

            $docFreq = $nbyte & 0x7F;

            for ($shift=7; ($nbyte & 0x80) != 0; $shift += 7) {

                $nbyte = ord($data[$pos++]);

                $docFreq |= ($nbyte & 0x7F) << $shift;

            }

            // $freqPointer     += $tiiFile->readVInt();

            $nbyte = ord($data[$pos++]);

            $vint = $nbyte & 0x7F;

            for ($shift=7; ($nbyte & 0x80) != 0; $shift += 7) {

                $nbyte = ord($data[$pos++]);

                $vint |= ($nbyte & 0x7F) << $shift;

            }

            $freqPointer += $vint;

            // $proxPointer     += $tiiFile->readVInt();

            $nbyte = ord($data[$pos++]);

            $vint = $nbyte & 0x7F;

            for ($shift=7; ($nbyte & 0x80) != 0; $shift += 7) {

                $nbyte = ord($data[$pos++]);

                $vint |= ($nbyte & 0x7F) << $shift;

            }

            $proxPointer += $vint;

            if( $docFreq >= $skipInterval ) {

                // $skipDelta = $tiiFile->readVInt();

                $nbyte = ord($data[$pos++]);

                $vint = $nbyte & 0x7F;

                for ($shift=7; ($nbyte & 0x80) != 0; $shift += 7) {

                    $nbyte = ord($data[$pos++]);

                    $vint |= ($nbyte & 0x7F) << $shift;

                }

                $skipDelta = $vint;

            } else {

                $skipDelta = 0;

            }

            // $indexPointer += $tiiFile->readVInt();

            $nbyte = ord($data[$pos++]);

            $vint = $nbyte & 0x7F;

            for ($shift=7; ($nbyte & 0x80) != 0; $shift += 7) {

                $nbyte = ord($data[$pos++]);

                $vint |= ($nbyte & 0x7F) << $shift;

            }

            $indexPointer += $vint;

            // $this->_termDictionary[] =  new Zend_Search_Lucene_Index_Term($termValue, $termFieldNum);

            $termDictionary[] = array($termFieldNum, $termValue);

            $termInfos[] =

                 // new Zend_Search_Lucene_Index_TermInfo($docFreq, $freqPointer, $proxPointer, $skipDelta, $indexPointer);

                 array($docFreq, $freqPointer, $proxPointer, $skipDelta, $indexPointer);

            $prevTerm = $termValue;

        }

        // Check special index entry mark

        if ($termDictionary[0][0] != (int)0xFFFFFFFF) {

            require_once 'Zend/Search/Lucene/Exception.php';

            throw new Zend_Search_Lucene_Exception('Wrong TermInfoIndexFile file format');

        }

        if (PHP_INT_SIZE > 4) {

            // Treat 64-bit 0xFFFFFFFF as -1

            $termDictionary[0][0] = -1;

        }

        return array($termDictionary, $termInfos);

    }

}