--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/yms/transcode.php	Fri Jul 31 23:51:08 2009 -0400
@@ -0,0 +1,79 @@
+<?php
+
+define('CHARSET_HEX', '0123456789abcdef');
+define('CHARSET_MODHEX', 'cbdefghijklnrtuv');
+define('CHARSET_BASE64', 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=');
+
+function yms_modhex_encode($str)
+{
+  if ( !preg_match('/^[' . CHARSET_HEX . ']+$/', $str) )
+    $str = yms_hex_encode($str);
+  
+  return strtr($str, '0123456789abcdef', 'cbdefghijklnrtuv');
+}
+
+function yms_modhex_decode($str)
+{
+  if ( !preg_match('/^[' . CHARSET_MODHEX . ']+$/', $str) )
+    return false;
+  
+  return strtr($str, 'cbdefghijklnrtuv', '0123456789abcdef');
+}
+
+function yms_hex_decode($str)
+{
+  if ( !preg_match('/^[' . CHARSET_HEX . ']+$/', $str) )
+    return false;
+  
+  if ( strlen($str) % 2 != 0 )
+    return '';
+  
+  $return = '';
+  for ( $i = 0; $i < strlen($str); $i+=2 )
+  {
+    $chr = substr($str, $i, 2);
+    $return .= chr(intval(hexdec($chr)));
+  }
+  return $return;
+}
+
+function yms_hex_encode($str)
+{
+  $return = '';
+  for ( $i = 0; $i < strlen($str); $i++ )
+  {
+    $chr = dechex(ord($str{$i}));
+    if ( strlen($chr) < 2 )
+      $chr = "0$chr";
+    $return .= $chr;
+  }
+  return $return;
+}
+
+function yms_tobinary($str)
+{
+  if ( preg_match('/^[' . CHARSET_HEX . ']+$/', $str) )
+  {
+    return yms_hex_decode($str);
+  }
+  else if ( preg_match('/^[' . CHARSET_MODHEX . ']+$/', $str) )
+  {
+    return yms_hex_decode(yms_modhex_decode($str));
+  }
+  else if ( preg_match('#^[' . CHARSET_BASE64 . ']+$#', $str) )
+  {
+    return base64_decode($str);
+  }
+  return $str;
+}
+
+function yms_randbin($len)
+{
+  $ret = '';
+  for ( $i = 0; $i < $len; $i++ )
+  {
+    $ret .= chr(mt_rand(0, 255));
+  }
+  return $ret;
+}
+