imap_utf7_decode

(PHP 4, PHP 5, PHP 7, PHP 8)

imap_utf7_decodeDecodes a modified UTF-7 encoded string

Description

imap_utf7_decode(string $string): string|false

Decodes modified UTF-7 string into ISO-8859-1 string.

This function is needed to decode mailbox names that contain certain characters which are not in range of printable ASCII characters.

Parameters

string

A modified UTF-7 encoding string, as defined in » RFC 2060, section 5.1.3.

Return Values

Returns a string that is encoded in ISO-8859-1 and consists of the same sequence of characters in string, or false if string contains invalid modified UTF-7 sequence or string contains a character that is not part of ISO-8859-1 character set.

See Also

add a note

User Contributed Notes 3 notes

up
10
Anonymous
9 years ago
I can't find method for converting imap utf7 into utf8.
So I have to write several lines of code to solve this issue. May be this could be usefull. Here is no error handling but it could be added.

Usage:
$imap_utf7 = '[Gmail]/&BBIEMAQ2BD0EPgQ1-';
$utf8 = ImapUtf7::decode($imap_utf7);
$imap_utf7_2 = ImapUtf7::encode($utf8);

[ImapUtf7.php]
<?php
class ImapUtf7 {
static
$imap_base64 =
'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,';
static private function
encode_b64imap($s) {
$a=0; $al=0; $res=''; $n=strlen($s);
for(
$i=0;$i<$n;$i++) {
$a=($a<<8)|ord($s[$i]); $al+=8;
for(;
$al>=6;$al-=6) $res.=self::$imap_base64[($a>>($al-6))&0x3F];
}
if (
$al>0) { $res.=self::$imap_base64[($a<<(6-$al))&0x3F]; }
return
$res;
}
static private function
encode_utf8_char($w) {
if (
$w&0x80000000) return '';
if (
$w&0xFC000000) $n=5; else
if (
$w&0xFFE00000) $n=4; else
if (
$w&0xFFFF0000) $n=3; else
if (
$w&0xFFFFF800) $n=2; else
if (
$w&0xFFFFFF80) $n=1; else return chr($w);
$res=chr(( (255<<(7-$n)) | ($w>>($n*6)) )&255);
while(--
$n>=0) $res.=chr((($w>>($n*6))&0x3F)|0x80);
return
$res;
}
static private function
decode_b64imap($s) {
$a=0; $al=0; $res=''; $n=strlen($s);
for(
$i=0;$i<$n;$i++) {
$k=strpos(self::$imap_base64,$s[$i]); if ($k===FALSE) continue;
$a=($a<<6)|$k; $al+=6;
if (
$al>=8) { $res.=chr(($a>>($al-8))&255);$al-=8; }
}
$r2=''; $n=strlen($res);
for(
$i=0;$i<$n;$i++) {
$c=ord($res[$i]); $i++;
if (
$i<$n) $c=($c<<8) | ord($res[$i]);
$r2.=self::encode_utf8_char($c);
}
return
$r2;
}
static function
encode($s) {
$n=strlen($s);$err=0;$buf='';$res='';
for(
$i=0;$i<$n;) {
$x=ord($s[$i++]);
if ((
$x&0x80)==0x00) { $r=$x;$w=0; }
else if ((
$x&0xE0)==0xC0) { $w=1; $r=$x &0x1F; }
else if ((
$x&0xF0)==0xE0) { $w=2; $r=$x &0x0F; }
else if ((
$x&0xF8)==0xF0) { $w=3; $r=$x &0x07; }
else if ((
$x&0xFC)==0xF8) { $w=4; $r=$x &0x03; }
else if ((
$x&0xFE)==0xFC) { $w=5; $r=$x &0x01; }
else if ((
$x&0xC0)==0x80) { $w=0; $r=-1; $err++; }
else {
$w=0;$r=-2;$err++; }
for(
$k=0;$k<$w && $i<$n; $k++) {
$x=ord($s[$i++]); if ($x&0xE0!=0x80) { $err++; }
$r=($r<<6)|($x&0x3F);
}
if (
$r<0x20 || $r>0x7E ) {
$buf.=chr(($r>>8)&0xFF); $buf.=chr($r&0xFF);
} else {
if (
strlen($buf)) {
$res.='&'.self::encode_b64imap($buf).'-';
$buf='';
}
if (
$r==0x26) { $res.='&-'; } else $res.=chr($r);
}
}
if (
strlen($buf)) $res.='&'.self::encode_b64imap($buf).'-';
return
$res;
}
static function
decode($s) {
$res=''; $n=strlen($s); $h=0;
while(
$h<$n) {
$t=strpos($s,'&',$h); if ($t===false) $t=$n;
$res.=substr($s,$h,$t-$h); $h=$t+1; if ($h>=$n) break;
$t=strpos($s,'-',$h); if ($t===false) $t=$n;
$k=$t-$h;
if (
$k==0) $res.='&';
else
$res.=self::decode_b64imap(substr($s,$h,$k));
$h=$t+1;
}
return
$res;
}
}
up
5
Anonymous
22 years ago
For "Outlook-style" UTF-7, you can also use:

mb_convert_encoding( $str, "ISO_8859-1", "UTF7-IMAP" ); # for decoding
mb_convert_encoding( $str, "UTF7-IMAP", "ISO_8859-1" ); # for encoding
up
3
Min He
14 years ago
For Chinese charset, we can use:

mb_convert_encoding($mailbox, "UTF7-IMAP", "GB2312");

when you want to create a mailbox in Chinese.

OR

mb_convert_encoding($mailbox, "GB2312", "UTF7-IMAP");

when you want to show the listed mailbox with the right charset.
To Top