Add MD5 alternative to directory hash calculation

config/config_local.example.php

@@ -52,6 +52,15 @@
  * (those that are displayed in a different color than other
  * "normal" mailboxes).
  *
+ * $hash_dirs_use_md5 (boolean) If set to TRUE, forces the
+ * hashed preferences directory calculation to use MD5 instead
+ * of CRC32.
+ *
+ * $hash_dirs_strip_domain (boolean) If set to TRUE, and if
+ * usernames are in full email address format, the domain
+ * part (beginning with "@") will be stripped before
+ * calculating the CRC or MD5.
+ *
  * $smtp_stream_options allows more control over the SSL context
  * used when connecting to the SMTP server over SSL/TLS.  See:
  * http://www.php.net/manual/context.php and in particular

doc/ChangeLog

@@ -395,6 +395,7 @@ Version 1.5.2 - SVN
   - Configuration tool now shows the SquirrelMail version
   - Prevent session lock-up caused by filters plugin trying to move
     messages in an account that is over quota.
+  - Added MD5 alternative to directory hash calculation
 
 Version 1.5.1 (branched on 2006-02-12)
 --------------------------------------

functions/prefs.php

@@ -112,25 +112,69 @@ function getHashedDir($username, $dir, $hash_dirs = '') {
 /**
  * Helper function for getHashDir which does the actual hash calculation.
  *
+ * Uses a crc32 algorithm by default, but if you put
+ * the following in config/config_local.php, you can
+ * force md5 instead:
+ *    $hash_dirs_use_md5 = TRUE;
+ *
+ * You may also specify that if usernames are in full
+ * email address format, the domain part (beginning
+ * with "@") be stripped before calculating the crc
+ * or md5.  Do that by putting the following in
+ * config/config_local.php:
+ *    $hash_dirs_strip_domain = TRUE;
+ *
  * @param string username the username to calculate the hash dir for
+ *
  * @return array a list of hash dirs for this username
+ *
  * @since 1.2.0
+ *
  */
 function computeHashDirs($username) {
-    /* Compute the hash for this user and extract the hash directories.  */ 
-    /* Note that the crc32() function result will be different on 32 and */ 
-    /* 64 bit systems, thus the hack below.                              */
-    $crc = crc32($username);
-    if ($crc & 0x80000000) {
-        $crc ^= 0xffffffff;
-        $crc += 1;
+
+    global $hash_dirs_use_md5, $hash_dirs_strip_domain;
+    static $hash_dirs = array();
+
+
+    // strip domain from username
+    if ($hash_dirs_strip_domain)
+        $user = substr($username, 0, strpos($username, '@'));
+    else
+        $user = $username;
+
+
+    // have we already calculated it?
+    if (!empty($hash_dirs[$user]))
+        return $hash_dirs[$user];
+
+
+    if ($hash_dirs_use_md5) {
+
+        $hash = md5($user);
+        //$hash = md5bin($user);
+
+    } else {
+
+        /* Compute the hash for this user and extract the hash directories.  */
+        /* Note that the crc32() function result will be different on 32 and */
+        /* 64 bit systems, thus the hack below.                              */
+        $crc = crc32($user);
+        if ($crc & 0x80000000) {
+            $crc ^= 0xffffffff;
+            $crc += 1;
+        }
+        $hash = base_convert($crc, 10, 16);
     }
-    $hash = base_convert($crc, 10, 16);
-    $hash_dirs = array();
+
+
+    $my_hash_dirs = array();
     for ($h = 0; $h < 4; ++ $h) {
-        $hash_dirs[] = substr($hash, $h, 1);
+        $my_hash_dirs[] = substr($hash, $h, 1);
     }
 
-    /* Return our array of hash directories. */
-    return ($hash_dirs);
+    // Return our array of hash directories
+    $hash_dirs[$user] = $my_hash_dirs;
+    return ($my_hash_dirs);
 }
+