Correct UTF-7 to UTF-8 conversion if mbstring is not available

2 files changed, 220 insertions, 356 deletions

diff --git a/program/include/main.inc b/program/include/main.inc
index bbda83aa7..c6e9857b0 100644
--- a/program/include/main.inc
+++ b/program/include/main.inc
@@ -893,7 +893,7 @@ function rcube_charset_convert($str, $from, $to=NULL)
 
   // convert string to UTF-8
   if ($from=='UTF-7')
-    $str = rcube_charset_convert(UTF7DecodeString($str), 'ISO-8859-1');
+    $str = utf7_to_utf8($str);
   else if (($from=='ISO-8859-1') && function_exists('utf8_encode'))
     $str = utf8_encode($str);
   else if ($from!='UTF-8')
@@ -904,7 +904,7 @@ function rcube_charset_convert($str, $from, $to=NULL)
 
   // encode string for output
   if ($to=='UTF-7')
-    return UTF7EncodeString(rcube_charset_convert($str, 'UTF-8', 'ISO-8859-1'));
+    return utf8_to_utf7($str);
   else if ($to=='ISO-8859-1' && function_exists('utf8_decode'))
     return utf8_decode($str);
   else if ($to!='UTF-8')
diff --git a/program/lib/utf7.inc b/program/lib/utf7.inc
index a887958cf..9ea5f6db5 100644
--- a/program/lib/utf7.inc
+++ b/program/lib/utf7.inc
@@ -1,384 +1,248 @@
 <?php
-//
-//
-//      utf7.inc - Routines to encode bytes to UTF7 and decode UTF7 strings
-//
-//      Copyright (C)  1999, 2002  Ziberex and Torben Rybner
-//
-//
-//      Version 1.01    2002-06-08      19:00
-//
-//      - Adapted for use in IlohaMail (modified UTF-7 decoding)
-//      - Converted from C to PHP4
-//
-//
-//      Version 1.00    1999-09-03      19:00
-//
-//      - Encodes bytes to UTF7 strings
-//          *OutString = '\0';
-//          StartBase64Encode();
-//          for (CP = InString;  *CP;  CP++)
-//            strcat(OutString, Base64Encode(*CP));
-//          strcat(OutString, StopBase64Encode());
-//      - Decodes Base64 strings to bytes
-//          StartBase64Decode();
-//          for (CP1 = InString, CP2 = OutString;  *CP1 && (*CP1 != '=');  CP1++)
-//            CP2 += Base64Decode(*CP1, CP2);
-//          StopBase64Decode();
-//
 
-$BASE64LENGTH              =  60;
-
-$BASE64DECODE_NO_DATA      = -1;
-$BASE64DECODE_EMPTY_DATA   = -2;
-$BASE64DECODE_INVALID_DATA = -3;
-
-
-//
-//
-//      Used for conversion to UTF7
-//
-$_ToUTF7 = array
-(
- 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
- 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
- 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
- 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', ','
-);
-
-//
-//
-//      Used for conversion from UTF7
-//      (0x80 => Illegal, 0x40 => CR/LF)
-//
-$_FromUTF7 = array
-(
-  0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,       // 00 - 07 - Ctrl -
-  0x80, 0x80, 0x40, 0x80, 0x80, 0x40, 0x80, 0x80,       // 08 - 0F - Ctrl -
-  0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,       // 10 - 17 - Ctrl -
-  0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,       // 18 - 1F - Ctrl -
-  0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,       // 20 - 27  !"#$%&'
-  0x80, 0x80, 0x80, 0x3E, 0x3F, 0x80, 0x80, 0x3F,       // 28 - 2F ()*+,-./
-  0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B,       // 30 - 37 01234567
-  0x3C, 0x3D, 0x80, 0x80, 0x80, 0x00, 0x80, 0x80,       // 38 - 3F 89:;<=>?
-  0x80, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,       // 40 - 47 @ABCDEFG
-  0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,       // 48 - 4F HIJKLMNO
-  0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16,       // 50 - 57 PQRSTUVW
-  0x17, 0x18, 0x19, 0x80, 0x80, 0x80, 0x80, 0x80,       // 58 - 5F XYZ[\]^_
-  0x80, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20,       // 60 - 67 `abcdefg
-  0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28,       // 68 - 6F hijklmno
-  0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F, 0x30,       // 70 - 77 pqrstuvw
-  0x31, 0x32, 0x33, 0x80, 0x80, 0x80, 0x80, 0x80,       // 78 - 7F xyz{|}~
-);
-
-
-//
-//
-//      UTF7EncodeInit:
-//
-//      Start the encoding of bytes
-//
-function UTF7EncodeInit(&$Context)
-{
-  $Context[ "Data" ]  = "";
-  $Context[ "Count" ] = 0;
-  $Context[ "Pos" ]   = 0;
-  $Context[ "State" ] = 0;
-} // UTF7EncodeInit
-
-
-//
-//
-//      UTF7EncodeByte:
-//
-//      Encodes one byte to UTF7
-//
-function UTF7EncodeByte(&$Context, $Byte)
-{
-  global $_ToUTF7;
-
-  $Byte = ord($Byte);
-  switch ($Context[ "State" ])
-  {
-    case 0:
-      // Convert into a byte
-      $Context[ "Data" ] = $_ToUTF7[ $Byte >> 2 ];
-      $Context[ "Pos" ]++;
-      // Save residue for next converted byte
-      $Context[ "Residue" ] = ($Byte & 0x03) << 4;
-      // This is the first byte in this line
-      $Context[ "Count" ] = 1;
-      // Next state is 1
-      $Context[ "State" ] = 1;
-      break;
- 
-    case 1:
-      // Convert into a byte
-      $Context[ "Data" ] .= $_ToUTF7[ $Context[ "Residue" ] | ($Byte >> 4) ];
-      $Context[ "Pos" ]++;
-      // Save residue for next converted byte
-      $Context[ "Residue" ] = ($Byte & 0x0F) << 2;
-      // Bumb byte counter
-      $Context[ "Count" ]++;
-      // Next state is 2
-      $Context[ "State" ] = 2;
-      break;
- 
-    case 2:
-      // Convert into a byte
-      $Context[ "Data" ] .= $_ToUTF7[ $Context[ "Residue" ] | ($Byte >> 6) ];
-      $Context[ "Pos" ]++;
-      // Residue fits precisely into the next byte
-      $Context[ "Data" ] .= $_ToUTF7[ $Byte & 0x3F ];
-      $Context[ "Pos" ]++;
-      // Bumb byte counter
-      $Context[ "Count" ]++;
-      // Next state is 3
-      $Context[ "State" ] = 3;
-      break;
-
-    case 3:
-      // Convert into a byte
-      $Context[ "Data" ] .= $_ToUTF7[ $Byte >> 2 ];
-      $Context[ "Pos" ]++;
-      // Save residue for next converted byte
-      $Context[ "Residue" ] = ($Byte & 0x03) << 4;
-      // Bumb byte counter
-      $Context[ "Count" ]++;
-      // Next state is 1
-      $Context[ "State" ] = 1;
-      break;
- 
-    default:
-      // printf("Internal error in UTF7Encode: State is %d\n", $Context[ "State" ]);
-      // exit(1);
-      break;
-  }
-} // UTF7EncodeByte
-
-
-//
-//
-//      UTF7EncodeFinal:
-//
-//      Terminates the encoding of bytes
-//
-function UTF7EncodeFinal(&$Context)
-{
-  if ($Context[ "State" ] == 0)
-    return "";
-  if ($Context[ "State" ] != 3)
-    UTF7EncodeByte($Context, "\0");
-  return $Context[ "Data" ];
-} // UTF7EncodeFinal
-
-
-//
-//
-//      UTF7EncodeString
-//
-//      Encodes a string to modified UTF-7 format
-//
-function UTF7EncodeString($String)
+/*
+ *  Copyright (C) 2000 Edmund Grimley Evans <edmundo@rano.org>
+ * 
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ * 
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  Translated from C to PHP by Thomas Bruederli <roundcube@gmail.com>
+ */ 
+
+
+/**
+ * Convert the data ($str) from RFC 2060's UTF-7 to UTF-8.
+ * If input data is invalid, return the original input string.
+ * RFC 2060 obviously intends the encoding to be unique (see
+ * point 5 in section 5.1.3), so we reject any non-canonical
+ * form, such as &ACY- (instead of &-) or &AMA-&AMA- (instead
+ * of &AMAAwA-).
+ */
+function utf7_to_utf8($str)
 {
-  // Not during encoding, yet
-  $Encoding = false;
-  // Go through the string
-  for ($I = 0;  $I < strlen($String);  $I++)
+  $Index_64 = array(
+      -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
+      -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
+      -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,62, 63,-1,-1,-1,
+      52,53,54,55, 56,57,58,59, 60,61,-1,-1, -1,-1,-1,-1,
+      -1, 0, 1, 2,  3, 4, 5, 6,  7, 8, 9,10, 11,12,13,14,
+      15,16,17,18, 19,20,21,22, 23,24,25,-1, -1,-1,-1,-1,
+      -1,26,27,28, 29,30,31,32, 33,34,35,36, 37,38,39,40,
+      41,42,43,44, 45,46,47,48, 49,50,51,-1, -1,-1,-1,-1
+  );
+
+  $u7len = strlen($str);
+  $p = $err = '';
+
+  for ($i=0; $u7len > 0; $i++, $u7len--)
   {
-    $Ch = substr($String, $I, 1);
-    if (ord($Ch) > 0x7F)
+    $u7 = $str{$i};
+    if ($u7 == '&')
     {
-      if (! $Encoding)
+      $i++;
+      $u7len--;
+      $u7 = $str{$i};
+      
+      if ($u7len && $u7 == '-')
       {
-        $RetVal .= "&";
-        $Encoding = true;
-        // Initialise UTF7 context
-        UTF7EncodeInit($Context);
+        $p .= '&';
+        continue;
       }
-      UTF7EncodeByte($Context, "\0");
-      UTF7EncodeByte($Context, $Ch);
-    }
-    elseif ($Ch == "&")
-    {
-      if (! $Encoding)
-      {
-        $RetVal .= "&";
-        $Encoding = true;
-        // Initialise UTF7 context
-        UTF7EncodeInit($Context);
-      }
-      else
+
+      $ch = 0;
+      $k = 10;
+      for (; $u7len > 0; $i++, $u7len--)
       {
-        UTF7EncodeByte($Context, "\0");
-        UTF7EncodeByte($Context, $Ch);
+        $u7 = $str{$i};
+
+        if ((ord($u7) & 0x80) || ($b = $Index_64[ord($u7)]) == -1)
+          break;
+
+        if ($k > 0)
+        {
+          $ch |= $b << $k;
+          $k -= 6;
+        }
+        else
+        {
+          $ch |= $b >> (-$k);
+          if ($ch < 0x80)
+          {
+            /* Printable US-ASCII */
+            if (0x20 <= $ch && $ch < 0x7f)
+              return $err;
+           $p .= chr($ch);
+          }
+          else if ($ch < 0x800)
+          {
+            $p .= chr(0xc0 | ($ch >> 6));
+            $p .= chr(0x80 | ($ch & 0x3f));
+          }
+          else
+          {
+            $p .= chr(0xe0 | ($ch >> 12));
+            $p .= chr(0x80 | (($ch >> 6) & 0x3f));
+            $p .= chr(0x80 | ($ch & 0x3f));
+          }
+
+          $ch = ($b << (16 + $k)) & 0xffff;
+          $k += 10;
+        }
       }
+
+      /* Non-zero or too many extra bits */
+      if ($ch || $k < 6)
+        return $err;
+        
+      /* BASE64 not properly terminated */
+      if (!$u7len || $u7 != '-')
+        return $err;
+        
+      /* Adjacent BASE64 sections */
+      if ($u7len > 2 && $str{$i+1} == '&' && $str{$i+2} != '-')
+        return $err;
     }
+    /* Not printable US-ASCII */
+    else if (ord($u7) < 0x20 || ord($u7) >= 0x7f)
+      return $err;
     else
-    {
-      if ($Encoding)
-      {
-        $RetVal .= UTF7EncodeFinal($Context) . "-$Ch";
-        $Encoding = false;
-      }
-      else
-        $RetVal .= $Ch;
-    }
+      $p .= $u7;
   }
-  if ($Encoding)
-    $RetVal .= UTF7EncodeFinal($Context) . "-";
-  return $RetVal;
-} // UTF7EncodeString
-
 
-//
-//
-//      UTF7DecodeInit:
-//
-//      Start the decoding of bytes
-//
-function UTF7DecodeInit(&$Context)
-{
-  $Context[ "Data" ]  = "";
-  $Context[ "State" ] = 0;
-  $Context[ "Pos" ]   = 0;
-} // UTF7DecodeInit
+  return $p;
+}
 
 
-//
-//
-//      UTF7DecodeByte:
-//
-//      Decodes one character from UTF7
-//
-function UTF7DecodeByte(&$Context, $Byte)
+/**
+ * Convert the data ($str) from UTF-8 to RFC 2060's UTF-7.
+ * Unicode characters above U+FFFF are replaced by U+FFFE.
+ * If input data is invalid, return an empty string.
+ */
+function utf8_to_utf7($str)
 {
-  global $BASE64DECODE_INVALID_DATA;
-  global $_FromUTF7;
-
-  // Restore bits
-  $Byte = $_FromUTF7[ ord($Byte) ];
-  // Ignore carriage returns and linefeeds
-  if ($Byte == 0x40)
-    return "";
-  // Invalid byte - Tell caller!
-  if ($Byte == 0x80)
-    $Context[ "Count" ] = $BASE64DECODE_INVALID_DATA;
-  switch ($Context[ "State" ])
+  $B64Chars = array(
+    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O',
+    'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd',
+    'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's',
+    't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7',
+    '8', '9', '+', ','
+  );
+
+  $u8len = strlen($str);
+  $base64 = $i = 0;
+  $p = $err = '';
+
+  while ($u8len)
   {
-    case 0:
-      // Save residue
-      $Context[ "Residue" ] = $Byte;
-      // Initialise count
-      $Context[ "Count" ] = 0;
-      // Next state
-      $Context[ "State" ] = 1;
-      break;
-
-    case 1:
-      // Store byte
-      $Context[ "Data" ] .= chr(($Context[ "Residue" ] << 2) | ($Byte >> 4));
-      $Context[ "Pos" ]++;
-      // Update count
-      $Context[ "Count" ]++;
-      // Save residue
-      $Context[ "Residue" ] = $Byte;
-      // Next state
-      $Context[ "State" ] = 2;
-      break;
-
-    case 2:
-      // Store byte
-      $Context[ "Data" ] .= chr(($Context[ "Residue" ] << 4) | ($Byte >> 2));
-      $Context[ "Pos" ]++;
-      // Update count
-      $Context[ "Count" ]++;
-      // Save residue
-      $Context[ "Residue" ] = $Byte;
-      // Next state
-      $Context[ "State" ] = 3;
-      break;
-
-    case 3:
-      // Store byte
-      $Context[ "Data" ] .= chr(($Context[ "Residue" ] << 6) | $Byte);
-      $Context[ "Pos" ]++;
-      // Update count
-      $Context[ "Count" ]++;
-      // Next state
-      $Context[ "State" ] = 4;
-      break;
+    $u8 = $str{$i};
+    $c = ord($u8);
+    
+    if ($c < 0x80)
+    {
+      $ch = $c;
+      $n = 0;
+    }
+    else if ($c < 0xc2)
+      return $err;
+    else if ($c < 0xe0)
+    {
+      $ch = $c & 0x1f;
+      $n = 1;
+    }
+    else if ($c < 0xf0)
+    {
+      $ch = $c & 0x0f;
+      $n = 2;
+    }
+    else if ($c < 0xf8)
+    {
+      $ch = $c & 0x07;
+      $n = 3;
+    }
+    else if ($c < 0xfc)
+    {
+      $ch = $c & 0x03;
+      $n = 4;
+    }
+    else if ($c < 0xfe)
+    {
+      $ch = $c & 0x01;
+      $n = 5;
+    }
+    else
+      return $err;
 
-    case 4:
-      // Save residue
-      $Context[ "Residue" ] = $Byte;
-      // Next state
-      $Context[ "State" ] = 1;
-      break;
-  }
-} // UTF7DecodeByte
+    $i++;
+    $u8len--;
 
+    if ($n > $u8len)
+      return $err;
 
-//
-//
-//      UTF7DecodeFinal:
-//
-//      Decodes one character from UTF7
-//
-function UTF7DecodeFinal(&$Context)
-{
-  // Buffer not empty - Return remainder!
-  if ($Context[ "Count" ])
-  {
-    $Context[ "Pos" ] = 0;
-    $Context[ "State" ] = 0;
-    return $Context[ "Data" ];
-  }
-  return "";
-} // UTF7DecodeFinal
-
-
-//
-//
-//      UTF7DecodeString
-//
-//      Converts a string encoded in modified UTF-7 encoding
-//      to ISO 8859-1.
-//      OBS: Works only for valid ISO 8859-1 characters in the
-//      encoded data
-//
-function UTF7DecodeString($String)
-{
-  $Decoding = false;
-  for ($I = 0;  $I < strlen($String);  $I++)
-  {
-    $Ch = substr($String, $I, 1);
-    if ($Decoding)
+    for ($j=0; $j < $n; $j++)
     {
-      if ($Ch == "-")
-      {
-        $RetVal .= UTF7DecodeFinal($Context);
-        $Decoding = false;
-      }
-      else
-        UTF7DecodeByte($Context, $Ch);
+      $o = ord($str{$i+$j});
+      if (($o & 0xc0) != 0x80)
+        return $err;
+      $ch = ($ch << 6) | ($o & 0x3f);
     }
-    elseif ($Ch == "&")
+    
+    if ($n > 1 && !($ch >> ($n * 5 + 1)))
+      return $err;
+    
+    $i += $n;
+    $u8len -= $n;
+
+    if ($ch < 0x20 || $ch >= 0x7f)
     {
-      if (($I < strlen($String) - 1) && (substr($String, $I + 1, 1) == "-"))
+      if (!$base64)
       {
-        $RetVal .= $Ch;
-        $I++;
+        $p .= '&';
+        $base64 = 1;
+        $b = 0;
+        $k = 10;
       }
-      else
+      if ($ch & ~0xffff)
+        $ch = 0xfffe;
+      
+      $p .= $B64Chars[($b | $ch >> $k)];
+      $k -= 6;
+      for (; $k >= 0; $k -= 6)
+        $p .= $B64Chars[(($ch >> $k) & 0x3f)];
+
+      $b = ($ch << (-$k)) & 0x3f;
+      $k += 16;
+    }
+    else
+    {
+      if ($base64)
       {
-        UTF7DecodeInit($Context);
-        $Decoding = true;
+        if ($k > 10)
+          $p .= $B64Chars[$b];
+        $p .= '-';
+        $base64 = 0;
       }
+      
+      $p .= chr($ch);
+      if (chr($ch) == '&')
+        $p .= '-';
     }
-    else
-      $RetVal .= $Ch;
   }
-  return str_replace("\0", "", $RetVal);
-} // UTF7DecodeString
+
+  if ($base64)
+  {
+    if ($k > 10)
+      $p .= $B64Chars[$b];
+    $p .= '-';
+  }
+
+  return $p;
+}
+
 ?>