<?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 Storage

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

 */

/**

 * @category   Zend

 * @package    Zend_Search_Lucene

 * @subpackage Storage

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

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

 */

abstract class Zend_Search_Lucene_Storage_File

{

    /**

     * Reads $length number of bytes at the current position in the

     * file and advances the file pointer.

     *

     * @param integer $length

     * @return string

     */

    abstract protected function _fread($length=1);

    /**

     * Sets the file position indicator and advances the file pointer.

     * The new position, measured in bytes from the beginning of the file,

     * is obtained by adding offset to the position specified by whence,

     * whose values are defined as follows:

     * SEEK_SET - Set position equal to offset bytes.

     * SEEK_CUR - Set position to current location plus offset.

     * SEEK_END - Set position to end-of-file plus offset. (To move to

     * a position before the end-of-file, you need to pass a negative value

     * in offset.)

     * Upon success, returns 0; otherwise, returns -1

     *

     * @param integer $offset

     * @param integer $whence

     * @return integer

     */

    abstract public function seek($offset, $whence=SEEK_SET);

    /**

     * Get file position.

     *

     * @return integer

     */

    abstract public function tell();

    /**

     * Flush output.

     *

     * Returns true on success or false on failure.

     *

     * @return boolean

     */

    abstract public function flush();

    /**

     * Writes $length number of bytes (all, if $length===null) to the end

     * of the file.

     *

     * @param string $data

     * @param integer $length

     */

    abstract protected function _fwrite($data, $length=null);

    /**

     * Lock file

     *

     * Lock type may be a LOCK_SH (shared lock) or a LOCK_EX (exclusive lock)

     *

     * @param integer $lockType

     * @return boolean

     */

    abstract public function lock($lockType, $nonBlockinLock = false);

    /**

     * Unlock file

     */

    abstract public function unlock();

    /**

     * Reads a byte from the current position in the file

     * and advances the file pointer.

     *

     * @return integer

     */

    public function readByte()

    {

        return ord($this->_fread(1));

    }

    /**

     * Writes a byte to the end of the file.

     *

     * @param integer $byte

     */

    public function writeByte($byte)

    {

        return $this->_fwrite(chr($byte), 1);

    }

    /**

     * Read num bytes from the current position in the file

     * and advances the file pointer.

     *

     * @param integer $num

     * @return string

     */

    public function readBytes($num)

    {

        return $this->_fread($num);

    }

    /**

     * Writes num bytes of data (all, if $num===null) to the end

     * of the string.

     *

     * @param string $data

     * @param integer $num

     */

    public function writeBytes($data, $num=null)

    {

        $this->_fwrite($data, $num);

    }

    /**

     * Reads an integer from the current position in the file

     * and advances the file pointer.

     *

     * @return integer

     */

    public function readInt()

    {

        $str = $this->_fread(4);

        return  ord($str[0]) << 24 |

                ord($str[1]) << 16 |

                ord($str[2]) << 8  |

                ord($str[3]);

    }

    /**

     * Writes an integer to the end of file.

     *

     * @param integer $value

     */

    public function writeInt($value)

    {

        settype($value, 'integer');

        $this->_fwrite( chr($value>>24 & 0xFF) .

                        chr($value>>16 & 0xFF) .

                        chr($value>>8  & 0xFF) .

                        chr($value     & 0xFF),   4  );

    }

    /**

     * Returns a long integer from the current position in the file

     * and advances the file pointer.

     *

     * @return integer|float

     * @throws Zend_Search_Lucene_Exception

     */

    public function readLong()

    {

        /**

         * Check, that we work in 64-bit mode.

         * fseek() uses long for offset. Thus, largest index segment file size in 32bit mode is 2Gb

         */

        if (PHP_INT_SIZE > 4) {

            $str = $this->_fread(8);

            return  ord($str[0]) << 56  |

                    ord($str[1]) << 48  |

                    ord($str[2]) << 40  |

                    ord($str[3]) << 32  |

                    ord($str[4]) << 24  |

                    ord($str[5]) << 16  |

                    ord($str[6]) << 8   |

                    ord($str[7]);

        } else {

            return $this->readLong32Bit();

        }

    }

    /**

     * Writes long integer to the end of file

     *

     * @param integer $value

     * @throws Zend_Search_Lucene_Exception

     */

    public function writeLong($value)

    {

        /**

         * Check, that we work in 64-bit mode.

         * fseek() and ftell() use long for offset. Thus, largest index segment file size in 32bit mode is 2Gb

         */

        if (PHP_INT_SIZE > 4) {

            settype($value, 'integer');

            $this->_fwrite( chr($value>>56 & 0xFF) .

                            chr($value>>48 & 0xFF) .

                            chr($value>>40 & 0xFF) .

                            chr($value>>32 & 0xFF) .

                            chr($value>>24 & 0xFF) .

                            chr($value>>16 & 0xFF) .

                            chr($value>>8  & 0xFF) .

                            chr($value     & 0xFF),   8  );

        } else {

            $this->writeLong32Bit($value);

        }

    }

    /**

     * Returns a long integer from the current position in the file,

     * advances the file pointer and return it as float (for 32-bit platforms).

     *

     * @return integer|float

     * @throws Zend_Search_Lucene_Exception

     */

    public function readLong32Bit()

    {

        $wordHigh = $this->readInt();

        $wordLow  = $this->readInt();

        if ($wordHigh & (int)0x80000000) {

            // It's a negative value since the highest bit is set

            if ($wordHigh == (int)0xFFFFFFFF  &&  ($wordLow & (int)0x80000000)) {

                return $wordLow;

            } else {

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

                throw new Zend_Search_Lucene_Exception('Long integers lower than -2147483648 (0x80000000) are not supported on 32-bit platforms.');

            }

        }

        if ($wordLow < 0) {

            // Value is large than 0x7FFF FFFF. Represent low word as float.

            $wordLow &= 0x7FFFFFFF;

            $wordLow += (float)0x80000000;

        }

        if ($wordHigh == 0) {

            // Return value as integer if possible

            return $wordLow;

        }

        return $wordHigh*(float)0x100000000/* 0x00000001 00000000 */ + $wordLow;

    }

    /**

     * Writes long integer to the end of file (32-bit platforms implementation)

     *

     * @param integer|float $value

     * @throws Zend_Search_Lucene_Exception

     */

    public function writeLong32Bit($value)

    {

        if ($value < (int)0x80000000) {

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

            throw new Zend_Search_Lucene_Exception('Long integers lower than -2147483648 (0x80000000) are not supported on 32-bit platforms.');

        }

        if ($value < 0) {

            $wordHigh = (int)0xFFFFFFFF;

            $wordLow  = (int)$value;

        } else {

            $wordHigh = (int)($value/(float)0x100000000/* 0x00000001 00000000 */);

            $wordLow  = $value - $wordHigh*(float)0x100000000/* 0x00000001 00000000 */;

            if ($wordLow > 0x7FFFFFFF) {

                // Highest bit of low word is set. Translate it to the corresponding negative integer value

                $wordLow -= 0x80000000;

                $wordLow |= 0x80000000;

            }

        }

        $this->writeInt($wordHigh);

        $this->writeInt($wordLow);

    }

    /**

     * Returns a variable-length integer from the current

     * position in the file and advances the file pointer.

     *

     * @return integer

     */

    public function readVInt()

    {

        $nextByte = ord($this->_fread(1));

        $val = $nextByte & 0x7F;

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

            $nextByte = ord($this->_fread(1));

            $val |= ($nextByte & 0x7F) << $shift;

        }

        return $val;

    }

    /**

     * Writes a variable-length integer to the end of file.

     *

     * @param integer $value

     */

    public function writeVInt($value)

    {

        settype($value, 'integer');

        while ($value > 0x7F) {

            $this->_fwrite(chr( ($value & 0x7F)|0x80 ));

            $value >>= 7;

        }

        $this->_fwrite(chr($value));

    }

    /**

     * Reads a string from the current position in the file

     * and advances the file pointer.

     *

     * @return string

     */

    public function readString()

    {

        $strlen = $this->readVInt();

        if ($strlen == 0) {

            return '';

        } else {

            /**

             * This implementation supports only Basic Multilingual Plane

             * (BMP) characters (from 0x0000 to 0xFFFF) and doesn't support

             * "supplementary characters" (characters whose code points are

             * greater than 0xFFFF)

             * Java 2 represents these characters as a pair of char (16-bit)

             * values, the first from the high-surrogates range (0xD800-0xDBFF),

             * the second from the low-surrogates range (0xDC00-0xDFFF). Then

             * they are encoded as usual UTF-8 characters in six bytes.

             * Standard UTF-8 representation uses four bytes for supplementary

             * characters.

             */

            $str_val = $this->_fread($strlen);

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

                if (( ord($str_val[$count]) & 0xC0 ) == 0xC0) {

                    $addBytes = 1;

                    if (ord($str_val[$count]) & 0x20 ) {

                        $addBytes++;

                        // Never used. Java2 doesn't encode strings in four bytes

                        if (ord($str_val[$count]) & 0x10 ) {

                            $addBytes++;

                        }

                    }

                    $str_val .= $this->_fread($addBytes);

                    $strlen += $addBytes;

                    // Check for null character. Java2 encodes null character

                    // in two bytes.

                    if (ord($str_val[$count])   == 0xC0 &&

                        ord($str_val[$count+1]) == 0x80   ) {

                        $str_val[$count] = 0;

                        $str_val = substr($str_val,0,$count+1)

                                 . substr($str_val,$count+2);

                    }

                    $count += $addBytes;

                }

            }

            return $str_val;

        }

    }

    /**

     * Writes a string to the end of file.

     *

     * @param string $str

     * @throws Zend_Search_Lucene_Exception

     */

    public function writeString($str)

    {

        /**

         * This implementation supports only Basic Multilingual Plane

         * (BMP) characters (from 0x0000 to 0xFFFF) and doesn't support

         * "supplementary characters" (characters whose code points are

         * greater than 0xFFFF)

         * Java 2 represents these characters as a pair of char (16-bit)

         * values, the first from the high-surrogates range (0xD800-0xDBFF),

         * the second from the low-surrogates range (0xDC00-0xDFFF). Then

         * they are encoded as usual UTF-8 characters in six bytes.

         * Standard UTF-8 representation uses four bytes for supplementary

         * characters.

         */

        // convert input to a string before iterating string characters

        settype($str, 'string');

        $chars = $strlen = strlen($str);

        $containNullChars = false;

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

            /**

             * String is already in Java 2 representation.

             * We should only calculate actual string length and replace

             * \x00 by \xC0\x80

             */

            if ((ord($str[$count]) & 0xC0) == 0xC0) {

                $addBytes = 1;

                if (ord($str[$count]) & 0x20 ) {

                    $addBytes++;

                    // Never used. Java2 doesn't encode strings in four bytes

                    // and we dont't support non-BMP characters

                    if (ord($str[$count]) & 0x10 ) {

                        $addBytes++;

                    }

                }

                $chars -= $addBytes;

                if (ord($str[$count]) == 0 ) {

                    $containNullChars = true;

                }

                $count += $addBytes;