<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\Mime\Encoder;

use Symfony\Component\Mime\CharacterStream;

/**
 * @author Chris Corbyn
 */
class QpEncoder implements EncoderInterface
{
    /**
     * Pre-computed QP for HUGE optimization.
     */
    private const QP_MAP = [
        0 => '=00', 1 => '=01', 2 => '=02', 3 => '=03', 4 => '=04',
        5 => '=05', 6 => '=06', 7 => '=07', 8 => '=08', 9 => '=09',
        10 => '=0A', 11 => '=0B', 12 => '=0C', 13 => '=0D', 14 => '=0E',
        15 => '=0F', 16 => '=10', 17 => '=11', 18 => '=12', 19 => '=13',
        20 => '=14', 21 => '=15', 22 => '=16', 23 => '=17', 24 => '=18',
        25 => '=19', 26 => '=1A', 27 => '=1B', 28 => '=1C', 29 => '=1D',
        30 => '=1E', 31 => '=1F', 32 => '=20', 33 => '=21', 34 => '=22',
        35 => '=23', 36 => '=24', 37 => '=25', 38 => '=26', 39 => '=27',
        40 => '=28', 41 => '=29', 42 => '=2A', 43 => '=2B', 44 => '=2C',
        45 => '=2D', 46 => '=2E', 47 => '=2F', 48 => '=30', 49 => '=31',
        50 => '=32', 51 => '=33', 52 => '=34', 53 => '=35', 54 => '=36',
        55 => '=37', 56 => '=38', 57 => '=39', 58 => '=3A', 59 => '=3B',
        60 => '=3C', 61 => '=3D', 62 => '=3E', 63 => '=3F', 64 => '=40',
        65 => '=41', 66 => '=42', 67 => '=43', 68 => '=44', 69 => '=45',
        70 => '=46', 71 => '=47', 72 => '=48', 73 => '=49', 74 => '=4A',
        75 => '=4B', 76 => '=4C', 77 => '=4D', 78 => '=4E', 79 => '=4F',
        80 => '=50', 81 => '=51', 82 => '=52', 83 => '=53', 84 => '=54',
        85 => '=55', 86 => '=56', 87 => '=57', 88 => '=58', 89 => '=59',
        90 => '=5A', 91 => '=5B', 92 => '=5C', 93 => '=5D', 94 => '=5E',
        95 => '=5F', 96 => '=60', 97 => '=61', 98 => '=62', 99 => '=63',
        100 => '=64', 101 => '=65', 102 => '=66', 103 => '=67', 104 => '=68',
        105 => '=69', 106 => '=6A', 107 => '=6B', 108 => '=6C', 109 => '=6D',
        110 => '=6E', 111 => '=6F', 112 => '=70', 113 => '=71', 114 => '=72',
        115 => '=73', 116 => '=74', 117 => '=75', 118 => '=76', 119 => '=77',
        120 => '=78', 121 => '=79', 122 => '=7A', 123 => '=7B', 124 => '=7C',
        125 => '=7D', 126 => '=7E', 127 => '=7F', 128 => '=80', 129 => '=81',
        130 => '=82', 131 => '=83', 132 => '=84', 133 => '=85', 134 => '=86',
        135 => '=87', 136 => '=88', 137 => '=89', 138 => '=8A', 139 => '=8B',
        140 => '=8C', 141 => '=8D', 142 => '=8E', 143 => '=8F', 144 => '=90',
        145 => '=91', 146 => '=92', 147 => '=93', 148 => '=94', 149 => '=95',
        150 => '=96', 151 => '=97', 152 => '=98', 153 => '=99', 154 => '=9A',
        155 => '=9B', 156 => '=9C', 157 => '=9D', 158 => '=9E', 159 => '=9F',
        160 => '=A0', 161 => '=A1', 162 => '=A2', 163 => '=A3', 164 => '=A4',
        165 => '=A5', 166 => '=A6', 167 => '=A7', 168 => '=A8', 169 => '=A9',
        170 => '=AA', 171 => '=AB', 172 => '=AC', 173 => '=AD', 174 => '=AE',
        175 => '=AF', 176 => '=B0', 177 => '=B1', 178 => '=B2', 179 => '=B3',
        180 => '=B4', 181 => '=B5', 182 => '=B6', 183 => '=B7', 184 => '=B8',
        185 => '=B9', 186 => '=BA', 187 => '=BB', 188 => '=BC', 189 => '=BD',
        190 => '=BE', 191 => '=BF', 192 => '=C0', 193 => '=C1', 194 => '=C2',
        195 => '=C3', 196 => '=C4', 197 => '=C5', 198 => '=C6', 199 => '=C7',
        200 => '=C8', 201 => '=C9', 202 => '=CA', 203 => '=CB', 204 => '=CC',
        205 => '=CD', 206 => '=CE', 207 => '=CF', 208 => '=D0', 209 => '=D1',
        210 => '=D2', 211 => '=D3', 212 => '=D4', 213 => '=D5', 214 => '=D6',
        215 => '=D7', 216 => '=D8', 217 => '=D9', 218 => '=DA', 219 => '=DB',
        220 => '=DC', 221 => '=DD', 222 => '=DE', 223 => '=DF', 224 => '=E0',
        225 => '=E1', 226 => '=E2', 227 => '=E3', 228 => '=E4', 229 => '=E5',
        230 => '=E6', 231 => '=E7', 232 => '=E8', 233 => '=E9', 234 => '=EA',
        235 => '=EB', 236 => '=EC', 237 => '=ED', 238 => '=EE', 239 => '=EF',
        240 => '=F0', 241 => '=F1', 242 => '=F2', 243 => '=F3', 244 => '=F4',
        245 => '=F5', 246 => '=F6', 247 => '=F7', 248 => '=F8', 249 => '=F9',
        250 => '=FA', 251 => '=FB', 252 => '=FC', 253 => '=FD', 254 => '=FE',
        255 => '=FF',
    ];

    private static array $safeMapShare = [];

    /**
     * A map of non-encoded ascii characters.
     *
     * @var string[]
     *
     * @internal
     */
    protected array $safeMap = [];

    public function __construct()
    {
        $id = static::class;
        if (!isset(self::$safeMapShare[$id])) {
            $this->initSafeMap();
            self::$safeMapShare[$id] = $this->safeMap;
        } else {
            $this->safeMap = self::$safeMapShare[$id];
        }
    }

    protected function initSafeMap(): void
    {
        foreach (array_merge([0x09, 0x20], range(0x21, 0x3C), range(0x3E, 0x7E)) as $byte) {
            $this->safeMap[$byte] = \chr($byte);
        }
    }

    /**
     * Takes an unencoded string and produces a QP encoded string from it.
     *
     * QP encoded strings have a maximum line length of 76 characters.
     * If the first line needs to be shorter, indicate the difference with
     * $firstLineOffset.
     */
    public function encodeString(string $string, ?string $charset = 'utf-8', int $firstLineOffset = 0, int $maxLineLength = 0): string
    {
        if ($maxLineLength > 76 || $maxLineLength <= 0) {
            $maxLineLength = 76;
        }

        $thisLineLength = $maxLineLength - $firstLineOffset;

        $lines = [];
        $lNo = 0;
        $lines[$lNo] = '';
        $currentLine = &$lines[$lNo++];
        $size = $lineLen = 0;
        $charStream = new CharacterStream($string, $charset);

        // Fetching more than 4 chars at one is slower, as is fetching fewer bytes
        // Conveniently 4 chars is the UTF-8 safe number since UTF-8 has up to 6
        // bytes per char and (6 * 4 * 3 = 72 chars per line) * =NN is 3 bytes
        while (null !== $bytes = $charStream->readBytes(4)) {
            $enc = $this->encodeByteSequence($bytes, $size);

            $i = strpos($enc, '=0D=0A');
            $newLineLength = $lineLen + (false === $i ? $size : $i);

            if ($currentLine && $newLineLength >= $thisLineLength) {
                $lines[$lNo] = '';
                $currentLine = &$lines[$lNo++];
                $thisLineLength = $maxLineLength;
                $lineLen = 0;
            }

            $currentLine .= $enc;

            if (false === $i) {
                $lineLen += $size;
            } else {
                // 6 is the length of '=0D=0A'.
                $lineLen = $size - strrpos($enc, '=0D=0A') - 6;
            }
        }

        return $this->standardize(implode("=\r\n", $lines));
    }

    /**
     * Encode the given byte array into a verbatim QP form.
     */
    private function encodeByteSequence(array $bytes, int &$size): string
    {
        $ret = '';
        $size = 0;
        foreach ($bytes as $b) {
            if (isset($this->safeMap[$b])) {
                $ret .= $this->safeMap[$b];
                ++$size;
            } else {
                $ret .= self::QP_MAP[$b];
                $size += 3;
            }
        }

        return $ret;
    }

    /**
     * Make sure CRLF is correct and HT/SPACE are in valid places.
     */
    private function standardize(string $string): string
    {
        $string = str_replace(["\t=0D=0A", ' =0D=0A', '=0D=0A'], ["=09\r\n", "=20\r\n", "\r\n"], $string);

        return match ($end = \ord(substr($string, -1))) {
            0x09,
            0x20 => substr_replace($string, self::QP_MAP[$end], -1),
            default => $string,
        };
    }
}

.NET Framework

Project Request

ProjectC

Vehicle Maintenance

Movie Navigator

Customers Exchange

ATM

.NET Core

Mail Daemon

Custom

Buns of code

PHP

Mediabox

Loan Castle

Content Management

Laravel

Phone Check

Frontend

Forex Wall

Business projects

Certification Center

Amerikas Auto

Pet projects

Geolocation Assistant

Web Dynamics

Blackball

Good old times

DOS Clock

BrainOut

Airport Administrator

Atomizer

Mediabox