<?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_Pdf

 * @subpackage Fonts

 * @copyright  Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)

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

 * @version    $Id: SegmentToDelta.php 24593 2012-01-05 20:35:02Z matthew $

 */

/** Zend_Pdf_Cmap */

require_once 'Zend/Pdf/Cmap.php';

/**

 * Implements the "segment mapping to delta values" character map (type 4).

 *

 * This is the Microsoft standard mapping table type for OpenType fonts. It

 * provides the ability to cover multiple contiguous ranges of the Unicode

 * character set, with the exception of Unicode Surrogates (U+D800 - U+DFFF).

 *

 * @package    Zend_Pdf

 * @subpackage Fonts

 * @copyright  Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)

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

 */

class Zend_Pdf_Cmap_SegmentToDelta extends Zend_Pdf_Cmap

{

  /**** Instance Variables ****/

    /**

     * The number of segments in the table.

     * @var integer

     */

    protected $_segmentCount = 0;

    /**

     * The size of the binary search range for segments.

     * @var integer

     */

    protected $_searchRange = 0;

    /**

     * The number of binary search steps required to cover the entire search

     * range.

     * @var integer

     */

    protected $_searchIterations = 0;

    /**

     * Array of ending character codes for each segment.

     * @var array

     */

    protected $_segmentTableEndCodes = array();

    /**

     * The ending character code for the segment at the end of the low search

     * range.

     * @var integer

     */

    protected $_searchRangeEndCode = 0;

    /**

     * Array of starting character codes for each segment.

     * @var array

     */

    protected $_segmentTableStartCodes = array();

    /**

     * Array of character code to glyph delta values for each segment.

     * @var array

     */

    protected $_segmentTableIdDeltas = array();

    /**

     * Array of offsets into the glyph index array for each segment.

     * @var array

     */

    protected $_segmentTableIdRangeOffsets = array();

    /**

     * Glyph index array. Stores glyph numbers, used with range offset.

     * @var array

     */

    protected $_glyphIndexArray = array();

  /**** Public Interface ****/

  /* Concrete Class Implementation */

    /**

     * Returns an array of glyph numbers corresponding to the Unicode characters.

     *

     * If a particular character doesn't exist in this font, the special 'missing

     * character glyph' will be substituted.

     *

     * See also {@link glyphNumberForCharacter()}.

     *

     * @param array $characterCodes Array of Unicode character codes (code points).

     * @return array Array of glyph numbers.

     */

    public function glyphNumbersForCharacters($characterCodes)

    {

        $glyphNumbers = array();

        foreach ($characterCodes as $key => $characterCode) {

            /* These tables only cover the 16-bit character range.

             */

            if ($characterCode > 0xffff) {

                $glyphNumbers[$key] = Zend_Pdf_Cmap::MISSING_CHARACTER_GLYPH;

                continue;

            }

            /* Determine where to start the binary search. The segments are

             * ordered from lowest-to-highest. We are looking for the first

             * segment whose end code is greater than or equal to our character

             * code.

             *

             * If the end code at the top of the search range is larger, then

             * our target is probably below it.

             *

             * If it is smaller, our target is probably above it, so move the

             * search range to the end of the segment list.

             */

            if ($this->_searchRangeEndCode >= $characterCode) {

                $searchIndex = $this->_searchRange;

            } else {

                $searchIndex = $this->_segmentCount;

            }

            /* Now do a binary search to find the first segment whose end code

             * is greater or equal to our character code. No matter the number

             * of segments (there may be hundreds in a large font), we will only

             * need to perform $this->_searchIterations.

             */

            for ($i = 1; $i <= $this->_searchIterations; $i++) {

                if ($this->_segmentTableEndCodes[$searchIndex] >= $characterCode) {

                    $subtableIndex = $searchIndex;

                    $searchIndex -= $this->_searchRange >> $i;

                } else {

                    $searchIndex += $this->_searchRange >> $i;

                }

            }

            /* If the segment's start code is greater than our character code,

             * that character is not represented in this font. Move on.

             */

            if ($this->_segmentTableStartCodes[$subtableIndex] > $characterCode) {

                $glyphNumbers[$key] = Zend_Pdf_Cmap::MISSING_CHARACTER_GLYPH;

                continue;

            }

            if ($this->_segmentTableIdRangeOffsets[$subtableIndex] == 0) {

                /* This segment uses a simple mapping from character code to

                 * glyph number.

                 */

                $glyphNumbers[$key] = ($characterCode + $this->_segmentTableIdDeltas[$subtableIndex]) % 65536;

            } else {

                /* This segment relies on the glyph index array to determine the

                 * glyph number. The calculation below determines the correct

                 * index into that array. It's a little odd because the range

                 * offset in the font file is designed to quickly provide an

                 * address of the index in the raw binary data instead of the

                 * index itself. Since we've parsed the data into arrays, we

                 * must process it a bit differently.

                 */

                $glyphIndex = ($characterCode - $this->_segmentTableStartCodes[$subtableIndex] +

                               $this->_segmentTableIdRangeOffsets[$subtableIndex] - $this->_segmentCount +

                               $subtableIndex - 1);

                $glyphNumbers[$key] = $this->_glyphIndexArray[$glyphIndex];

            }

        }

        return $glyphNumbers;

    }

    /**

     * Returns the glyph number corresponding to the Unicode character.

     *

     * If a particular character doesn't exist in this font, the special 'missing

     * character glyph' will be substituted.

     *

     * See also {@link glyphNumbersForCharacters()} which is optimized for bulk

     * operations.

     *

     * @param integer $characterCode Unicode character code (code point).

     * @return integer Glyph number.

     */

    public function glyphNumberForCharacter($characterCode)

    {

        /* This code is pretty much a copy of glyphNumbersForCharacters().

         * See that method for inline documentation.

         */

        if ($characterCode > 0xffff) {

            return Zend_Pdf_Cmap::MISSING_CHARACTER_GLYPH;

        }

        if ($this->_searchRangeEndCode >= $characterCode) {

            $searchIndex = $this->_searchRange;

        } else {

            $searchIndex = $this->_segmentCount;

        }

        for ($i = 1; $i <= $this->_searchIterations; $i++) {

            if ($this->_segmentTableEndCodes[$searchIndex] >= $characterCode) {

                $subtableIndex = $searchIndex;

                $searchIndex -= $this->_searchRange >> $i;

            } else {

                $searchIndex += $this->_searchRange >> $i;

            }

        }

        if ($this->_segmentTableStartCodes[$subtableIndex] > $characterCode) {

            return Zend_Pdf_Cmap::MISSING_CHARACTER_GLYPH;

        }

        if ($this->_segmentTableIdRangeOffsets[$subtableIndex] == 0) {

            $glyphNumber = ($characterCode + $this->_segmentTableIdDeltas[$subtableIndex]) % 65536;

        } else {

            $glyphIndex = ($characterCode - $this->_segmentTableStartCodes[$subtableIndex] +

                           $this->_segmentTableIdRangeOffsets[$subtableIndex] - $this->_segmentCount +

                           $subtableIndex - 1);

            $glyphNumber = $this->_glyphIndexArray[$glyphIndex];

        }

        return $glyphNumber;

    }

    /**

     * Returns an array containing the Unicode characters that have entries in

     * this character map.

     *

     * @return array Unicode character codes.

     */

    public function getCoveredCharacters()

    {

        $characterCodes = array();

        for ($i = 1; $i <= $this->_segmentCount; $i++) {

            for ($code = $this->_segmentTableStartCodes[$i]; $code <= $this->_segmentTableEndCodes[$i]; $code++) {

                $characterCodes[] = $code;

            }

        }

        return $characterCodes;

    }

    /**

     * Returns an array containing the glyphs numbers that have entries in this character map.

     * Keys are Unicode character codes (integers)

     *

     * This functionality is partially covered by glyphNumbersForCharacters(getCoveredCharacters())

     * call, but this method do it in more effective way (prepare complete list instead of searching

     * glyph for each character code).

     *

     * @internal

     * @return array Array representing <Unicode character code> => <glyph number> pairs.

     */

    public function getCoveredCharactersGlyphs()

    {

        $glyphNumbers = array();

        for ($segmentNum = 1; $segmentNum <= $this->_segmentCount; $segmentNum++) {

            if ($this->_segmentTableIdRangeOffsets[$segmentNum] == 0) {

                $delta = $this->_segmentTableIdDeltas[$segmentNum];

                for ($code =  $this->_segmentTableStartCodes[$segmentNum];

                     $code <= $this->_segmentTableEndCodes[$segmentNum];

                     $code++) {

                    $glyphNumbers[$code] = ($code + $delta) % 65536;

                }

            } else {

                $code       = $this->_segmentTableStartCodes[$segmentNum];

                $glyphIndex = $this->_segmentTableIdRangeOffsets[$segmentNum] - ($this->_segmentCount - $segmentNum) - 1;

                while ($code <= $this->_segmentTableEndCodes[$segmentNum]) {

                    $glyphNumbers[$code] = $this->_glyphIndexArray[$glyphIndex];

                    $code++;

                    $glyphIndex++;

                }

            }

        }

        return $glyphNumbers;

    }

  /* Object Lifecycle */

    /**

     * Object constructor

     *

     * Parses the raw binary table data. Throws an exception if the table is

     * malformed.

     *

     * @param string $cmapData Raw binary cmap table data.

     * @throws Zend_Pdf_Exception

     */

    public function __construct($cmapData)

    {

        /* Sanity check: The table should be at least 23 bytes in size.

         */

        $actualLength = strlen($cmapData);

        if ($actualLength < 23) {

            require_once 'Zend/Pdf/Exception.php';

            throw new Zend_Pdf_Exception('Insufficient table data',

                                         Zend_Pdf_Exception::CMAP_TABLE_DATA_TOO_SMALL);

        }

        /* Sanity check: Make sure this is right data for this table type.

         */

        $type = $this->_extractUInt2($cmapData, 0);

        if ($type != Zend_Pdf_Cmap::TYPE_SEGMENT_TO_DELTA) {

            require_once 'Zend/Pdf/Exception.php';

            throw new Zend_Pdf_Exception('Wrong cmap table type',

                                         Zend_Pdf_Exception::CMAP_WRONG_TABLE_TYPE);

        }

        $length = $this->_extractUInt2($cmapData, 2);

        if ($length != $actualLength) {

            require_once 'Zend/Pdf/Exception.php';

            throw new Zend_Pdf_Exception("Table length ($length) does not match actual length ($actualLength)",

                                         Zend_Pdf_Exception::CMAP_WRONG_TABLE_LENGTH);

        }

        /* Mapping tables should be language-independent. The font may not work

         * as expected if they are not. Unfortunately, many font files in the

         * wild incorrectly record a language ID in this field, so we can't

         * call this a failure.

         */

        $language = $this->_extractUInt2($cmapData, 4);

        if ($language != 0) {

            // Record a warning here somehow?

        }

        /* These two values are stored premultiplied by two which is convienent

         * when using the binary data directly, but we're parsing it out to

         * native PHP data types, so divide by two.

         */

        $this->_segmentCount = $this->_extractUInt2($cmapData, 6) >> 1;

        $this->_searchRange  = $this->_extractUInt2($cmapData, 8) >> 1;

        $this->_searchIterations = $this->_extractUInt2($cmapData, 10) + 1;

        $offset = 14;

        for ($i = 1; $i <= $this->_segmentCount; $i++, $offset += 2) {

            $this->_segmentTableEndCodes[$i] = $this->_extractUInt2($cmapData, $offset);

        }

        $this->_searchRangeEndCode = $this->_segmentTableEndCodes[$this->_searchRange];

        $offset += 2;    // reserved bytes

        for ($i = 1; $i <= $this->_segmentCount; $i++, $offset += 2) {

            $this->_segmentTableStartCodes[$i] = $this->_extractUInt2($cmapData, $offset);

        }

        for ($i = 1; $i <= $this->_segmentCount; $i++, $offset += 2) {

            $this->_segmentTableIdDeltas[$i] = $this->_extractInt2($cmapData, $offset);    // signed

        }

        /* The range offset helps determine the index into the glyph index array.

         * Like the segment count and search range above, it's stored as a byte

         * multiple in the font, so divide by two as we extract the values.

         */

        for ($i = 1; $i <= $this->_segmentCount; $i++, $offset += 2) {

            $this->_segmentTableIdRangeOffsets[$i] = $this->_extractUInt2($cmapData, $offset) >> 1;

        }

        /* The size of the glyph index array varies by font and depends on the

         * extent of the usage of range offsets versus deltas. Some fonts may

         * not have any entries in this array.

         */

        for (; $offset < $length; $offset += 2) {

            $this->_glyphIndexArray[] = $this->_extractUInt2($cmapData, $offset);

        }

        /* Sanity check: After reading all of the data, we should be at the end

         * of the table.

         */

        if ($offset != $length) {

            require_once 'Zend/Pdf/Exception.php';

            throw new Zend_Pdf_Exception("Ending offset ($offset) does not match length ($length)",

                                         Zend_Pdf_Exception::CMAP_FINAL_OFFSET_NOT_LENGTH);

        }

    }

}