<?php
// File name:	mimeenc.inc.php
// Description:	PHP subroutine to handle MIME encoding/decoding (Base-64 and Quoted-Printable)
// Date:	2004-04-27
// Author:	imacat <imacat@pristine.com.tw>
// Copyright:	Copyright (C) 2004-2007 Pristine Communications

// b64encode_header: Encode a piece of header text with Base-64
// Refer to RFC-1522 4.1
function b64encode_header($text, $charset)
{
    return "=?$charset?B?" . base64_encode($text) . "?=";
}

// qpencode: Encode a piece of text with Quoted-Printable
// Refer to RFC-1521 5.1
function qpencode($source)
{
    // Convert to RFC-822 CRLF (Rule #4)
    $source = str_replace("\r\n", "\n", $source);
    $source = str_replace("\n", "\r\n", $source);
    $result = "";
    // Convert each character
    for ($i = 0, $linelen = 0; $i < strlen($source); $i++) {
        // Rule #4 (Line Breaks)
        if (substr($source, $i, 2) == "\r\n") {
            $result .= "\r\n";
            $linelen = 0;
            $i++;
            continue;
        }
        $c = substr($source, $i, 1);
        $o = ord($c);
        // Rule #2 (Literal representation)
        if (($o >= 33 && $o <= 60) || ($o >= 62 && $o <= 126)) {
            $char = $c;
        // Rule #4 (Line Breaks)
        } elseif ($c == "\r" || $c == "\n") {
            $char = $c;
        // Rule #3 (White Space)
        } elseif ($o == 9 || $o == 32) {
            // At the end of line
            if ($i+1 == strlen($source) || substr($source, $i+1) == "\r") {
                $char = sprintf("=%02X", $o);
            // Not at the end of line
            } else {
                $char = $c;
            }
        // Rule #1 (General 8-bit representation)
        } else {
            $char = sprintf("=%02X", $o);
        }
        // Rule #5 (Soft Line Breaks)
        if ($linelen + strlen($char) > 75) {
            $result .= "=\r\n";
            $linelen = 0;
        }
        $result .= $char;
        $linelen += strlen($char);
    }
    return $result;
}

// qpencode_header: Encode a piece of header text with Quoted-Printable
// Refer to RFC-1522 4.2
function qpencode_header($source, $charset)
{
    $result = "";
    // Convert each character
    for ($i = 0; $i < strlen($source); $i++) {
        $c = substr($source, $i, 1);
        $o = ord($c);
        // 4.2.3
        if ($o >= 33 && $o <= 126 && $c != "=" && $c != "?" && $c != "_" && $o != 32) {
            $char = $c;
        // 4.2.2
        } elseif ($o == 32) {
            $char = "_";
        // 4.2.1
        } else {
            $char = sprintf("=%02X", $o);
        }
        $result .= $char;
    }
    $result = "=?$charset?Q?$result?=";
    return $result;
}

?>