<?php

/*
 * This file is part of SwiftMailer.
 * (c) 2004-2009 Chris Corbyn
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

/**
 * Analyzes UTF-8 characters.
 *
 * @author     Chris Corbyn
 * @author     Xavier De Cock <xdecock@gmail.com>
 */
class Swift_CharacterReader_Utf8Reader implements Swift_CharacterReader
{
    /** Pre-computed for optimization */
    private static $length_map=array(
        // N=0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,
        1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x0N
        1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x1N
        1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x2N
        1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x3N
        1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x4N
        1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x5N
        1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x6N
        1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x7N
        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 0x8N
        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 0x9N
        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 0xAN
        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 0xBN
        2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, // 0xCN
        2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, // 0xDN
        3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3, // 0xEN
        4,4,4,4,4,4,4,4,5,5,5,5,6,6,0,0  // 0xFN
    );

    private static $s_length_map=array(
        "\x00"=>1, "\x01"=>1, "\x02"=>1, "\x03"=>1, "\x04"=>1, "\x05"=>1, "\x06"=>1, "\x07"=>1,
        "\x08"=>1, "\x09"=>1, "\x0a"=>1, "\x0b"=>1, "\x0c"=>1, "\x0d"=>1, "\x0e"=>1, "\x0f"=>1,
        "\x10"=>1, "\x11"=>1, "\x12"=>1, "\x13"=>1, "\x14"=>1, "\x15"=>1, "\x16"=>1, "\x17"=>1,
        "\x18"=>1, "\x19"=>1, "\x1a"=>1, "\x1b"=>1, "\x1c"=>1, "\x1d"=>1, "\x1e"=>1, "\x1f"=>1,
        "\x20"=>1, "\x21"=>1, "\x22"=>1, "\x23"=>1, "\x24"=>1, "\x25"=>1, "\x26"=>1, "\x27"=>1,
        "\x28"=>1, "\x29"=>1, "\x2a"=>1, "\x2b"=>1, "\x2c"=>1, "\x2d"=>1, "\x2e"=>1, "\x2f"=>1,
        "\x30"=>1, "\x31"=>1, "\x32"=>1, "\x33"=>1, "\x34"=>1, "\x35"=>1, "\x36"=>1, "\x37"=>1,
        "\x38"=>1, "\x39"=>1, "\x3a"=>1, "\x3b"=>1, "\x3c"=>1, "\x3d"=>1, "\x3e"=>1, "\x3f"=>1,
        "\x40"=>1, "\x41"=>1, "\x42"=>1, "\x43"=>1, "\x44"=>1, "\x45"=>1, "\x46"=>1, "\x47"=>1,
        "\x48"=>1, "\x49"=>1, "\x4a"=>1, "\x4b"=>1, "\x4c"=>1, "\x4d"=>1, "\x4e"=>1, "\x4f"=>1,
        "\x50"=>1, "\x51"=>1, "\x52"=>1, "\x53"=>1, "\x54"=>1, "\x55"=>1, "\x56"=>1, "\x57"=>1,
        "\x58"=>1, "\x59"=>1, "\x5a"=>1, "\x5b"=>1, "\x5c"=>1, "\x5d"=>1, "\x5e"=>1, "\x5f"=>1,
        "\x60"=>1, "\x61"=>1, "\x62"=>1, "\x63"=>1, "\x64"=>1, "\x65"=>1, "\x66"=>1, "\x67"=>1,
        "\x68"=>1, "\x69"=>1, "\x6a"=>1, "\x6b"=>1, "\x6c"=>1, "\x6d"=>1, "\x6e"=>1, "\x6f"=>1,
        "\x70"=>1, "\x71"=>1, "\x72"=>1, "\x73"=>1, "\x74"=>1, "\x75"=>1, "\x76"=>1, "\x77"=>1,
        "\x78"=>1, "\x79"=>1, "\x7a"=>1, "\x7b"=>1, "\x7c"=>1, "\x7d"=>1, "\x7e"=>1, "\x7f"=>1,
        "\x80"=>0, "\x81"=>0, "\x82"=>0, "\x83"=>0, "\x84"=>0, "\x85"=>0, "\x86"=>0, "\x87"=>0,
        "\x88"=>0, "\x89"=>0, "\x8a"=>0, "\x8b"=>0, "\x8c"=>0, "\x8d"=>0, "\x8e"=>0, "\x8f"=>0,
        "\x90"=>0, "\x91"=>0, "\x92"=>0, "\x93"=>0, "\x94"=>0, "\x95"=>0, "\x96"=>0, "\x97"=>0,
        "\x98"=>0, "\x99"=>0, "\x9a"=>0, "\x9b"=>0, "\x9c"=>0, "\x9d"=>0, "\x9e"=>0, "\x9f"=>0,
        "\xa0"=>0, "\xa1"=>0, "\xa2"=>0, "\xa3"=>0, "\xa4"=>0, "\xa5"=>0, "\xa6"=>0, "\xa7"=>0,
        "\xa8"=>0, "\xa9"=>0, "\xaa"=>0, "\xab"=>0, "\xac"=>0, "\xad"=>0, "\xae"=>0, "\xaf"=>0,
        "\xb0"=>0, "\xb1"=>0, "\xb2"=>0, "\xb3"=>0, "\xb4"=>0, "\xb5"=>0, "\xb6"=>0, "\xb7"=>0,
        "\xb8"=>0, "\xb9"=>0, "\xba"=>0, "\xbb"=>0, "\xbc"=>0, "\xbd"=>0, "\xbe"=>0, "\xbf"=>0,
        "\xc0"=>2, "\xc1"=>2, "\xc2"=>2, "\xc3"=>2, "\xc4"=>2, "\xc5"=>2, "\xc6"=>2, "\xc7"=>2,
        "\xc8"=>2, "\xc9"=>2, "\xca"=>2, "\xcb"=>2, "\xcc"=>2, "\xcd"=>2, "\xce"=>2, "\xcf"=>2,
        "\xd0"=>2, "\xd1"=>2, "\xd2"=>2, "\xd3"=>2, "\xd4"=>2, "\xd5"=>2, "\xd6"=>2, "\xd7"=>2,
        "\xd8"=>2, "\xd9"=>2, "\xda"=>2, "\xdb"=>2, "\xdc"=>2, "\xdd"=>2, "\xde"=>2, "\xdf"=>2,
        "\xe0"=>3, "\xe1"=>3, "\xe2"=>3, "\xe3"=>3, "\xe4"=>3, "\xe5"=>3, "\xe6"=>3, "\xe7"=>3,
        "\xe8"=>3, "\xe9"=>3, "\xea"=>3, "\xeb"=>3, "\xec"=>3, "\xed"=>3, "\xee"=>3, "\xef"=>3,
        "\xf0"=>4, "\xf1"=>4, "\xf2"=>4, "\xf3"=>4, "\xf4"=>4, "\xf5"=>4, "\xf6"=>4, "\xf7"=>4,
        "\xf8"=>5, "\xf9"=>5, "\xfa"=>5, "\xfb"=>5, "\xfc"=>6, "\xfd"=>6, "\xfe"=>0, "\xff"=>0,
     );

    /**
     * Returns the complete character map.
     *
     * @param string  $string
     * @param int     $startOffset
     * @param array   $currentMap
     * @param mixed   $ignoredChars
     *
     * @return int
     */
    public function getCharPositions($string, $startOffset, &$currentMap, &$ignoredChars)
    {
        if (!isset($currentMap['i']) || ! isset($currentMap['p'])) {
            $currentMap['p'] = $currentMap['i'] = array();
        }

        $strlen=strlen($string);
        $charPos=count($currentMap['p']);
        $foundChars=0;
        $invalid=false;
        for ($i = 0; $i < $strlen; ++$i) {
            $char = $string[$i];
            $size = self::$s_length_map[$char];
            if ($size == 0) {
                /* char is invalid, we must wait for a resync */
                $invalid = true;
                continue;
            } else {
                if ($invalid == true) {
                    /* We mark the chars as invalid and start a new char */
                    $currentMap['p'][$charPos + $foundChars] = $startOffset + $i;
                    $currentMap['i'][$charPos + $foundChars] = true;
                    ++$foundChars;
                    $invalid = false;
                }
                if (($i + $size) > $strlen) {
                    $ignoredChars = substr($string, $i);
                    break;
                }
                for ($j = 1; $j < $size; ++$j) {
                    $char = $string[$i + $j];
                    if ($char > "\x7F" && $char < "\xC0") {
                        // Valid - continue parsing
                    } else {
                        /* char is invalid, we must wait for a resync */
                        $invalid = true;
                        continue 2;
                    }
                }
                /* Ok we got a complete char here */
                $currentMap['p'][$charPos + $foundChars] = $startOffset + $i + $size;
                $i += $j - 1;
                ++$foundChars;
            }
        }

        return $foundChars;
    }

    /**
     * Returns mapType.
     *
     * @return int     mapType
     */
    public function getMapType()
    {
        return self::MAP_TYPE_POSITIONS;
    }

    /**
     * Returns an integer which specifies how many more bytes to read.
     *
     * A positive integer indicates the number of more bytes to fetch before invoking
     * this method again.
     * A value of zero means this is already a valid character.
     * A value of -1 means this cannot possibly be a valid character.
     *
     * @param string  $bytes
     * @param int     $size
     *
     * @return int
     */
    public function validateByteSequence($bytes, $size)
    {
        if ($size<1) {
            return -1;
        }
        $needed = self::$length_map[$bytes[0]] - $size;

        return ($needed > -1)
            ? $needed
            : -1
            ;
    }

    /**
     * Returns the number of bytes which should be read to start each character.
     *
     * @return int
     */
    public function getInitialByteSize()
    {
        return 1;
    }
}