mango r187 - in trunk: . lib

[ovitters svn gnome org]

Author: ovitters
Date: Mon Jun  2 18:55:59 2008
New Revision: 187
URL: http://svn.gnome.org/viewvc/mango?rev=187&view=rev

Log:
	* lib/ber.php: Add BER decoder. Mango doesn't need it, but I thought
	it would, so let's just add it anyway.



Added:
   trunk/lib/ber.php
Modified:
   trunk/ChangeLog

Added: trunk/lib/ber.php
==============================================================================
--- (empty file)
+++ trunk/lib/ber.php	Mon Jun  2 18:55:59 2008
@@ -0,0 +1,86 @@
+<?
+
+# Straigth port from the BER class from python-paramiko
+# Note: ignored the encoding stuff
+
+class BER {
+
+    private
+        $idx = 0,
+        $content;
+
+    function __construct($data) {
+        $this->idx = 0;
+        $this->content = $data;
+    }
+
+    public function decode() {
+        return $this->decode_next();
+    }
+
+    public function decode_next() {
+        if ($this->idx > strlen($this->content))
+            return null;
+
+        $ident = ord($this->content{$this->idx});
+        $this->idx += 1;
+        print "ident: $ident\n";
+        if (($ident & 31) == 31) {
+            # identifier > 30
+            $ident = 0;
+            while ($this->idx < strlen($this->content)) {
+                $t = ord($this->content{$this->idx});
+                $this->idx += 1;
+                $ident = ($ident << 7) | ($t & 0x7f);
+                if (!(t & 0x80))
+                    break;
+            }
+        }
+        if ($this->idx >= strlen($this->content))
+            return null;
+        # now fetch length
+        $size = ord($this->content{$this->idx});
+        $this->idx += 1;
+        if ($size & 0x80) {
+            # more complimicated...
+            # FIXME: theoretically should handle indefinite-length (0x80)
+            $t = $size & 0x7f;
+            if ($this->idx + t > strlen($this->content))
+                return null;
+            $size = inflate_long(substr($this->content, $this->idx, $this->idx + t), True);
+            $this->idx += t;
+        }
+        if ($this->idx + $size > strlen($this->content))
+            # can't fit
+            return null;
+        $data = substr($this->content, $this->idx, $this->idx + $size);
+        $this->idx += $size;
+        # now switch on id
+        if ($ident == 0x30)
+            # sequence
+            return BER::decode_sequence($data);
+        elseif ($ident == 2) {
+            # int
+            return inflate_long($data);
+        }
+        else {
+            # 1: boolean (00 false, otherwise true)
+            throw new Exception("Unknown ber encoding type $ident (robey is lazy) idx $this->idx");
+        }
+
+    }
+
+    static function decode_sequence($data) {
+        $out = array();
+        $b = new BER($data);
+        while (true) {
+            $x = $b.decode_next();
+            if (is_null($x))
+                break;
+            $out[] = $x;
+        }
+        return $out;
+    }
+}
+
+?>