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bindings/py/pypcp/context.py

@@ -0,0 +1,69 @@
+from pypcp.dll import *
+from pypcp.stream import *
+
+class Context(object):
+    def __init__(self):
+        self._ctx = libpcp.ptx_new()
+        self._sk = None
+
+    def __del__(self):
+        libpcp.ptx_clean(self._ctx)
+
+    def throw(self, E=None, msg=None):
+        # forward libpcp generated exceptions
+        pcpmsg = ffi.string(self._ctx.pcp_err)
+        if msg:
+            pcpmsg = "%s: %s" % (msg, pcpmsg)
+        if E:
+            raise E(pcpmsg)
+        else:
+            raise RuntimeError(pcpmsg)
+
+    def addkey(self, Key):
+        self._sk = Key._sk
+
+    def pubkeycount(self):
+        return libpcp.pcphash_countpub(self._ctx)
+
+    def recipients(self, *recipients):
+        for key in recipients:
+            libpcp.pcphash_add(self._ctx, key._pk, key._pk.type)
+
+    def encrypt(self, string=None, file=None, sign=False, passphrase=None):
+        anon = 0
+        instream = None
+        outstream = None
+        
+        if string:
+            instream = Stream(string=string)
+        else:
+            instream = Stream(file)
+
+        outstream = Stream()
+            
+        if self.pubkeycount() > 0:
+            if not self._sk:
+                anon = 1
+                
+            dosign = 0
+            if sign:
+                dosign = 1
+
+            size = libpcp.pcp_encrypt_stream(self._ctx, instream._stream, outstream._stream,
+                                             self._sk, self._ctx.pcppubkey_hash, dosign, anon)
+
+            if size <= 0:
+                self.throw(IOError, "failed to encrypt")
+
+            return ffi.buffer(libpcp.buffer_get_remainder(outstream._stream.b), libpcp.buffer_size(outstream._stream.b))[:]
+            
+        else:
+            # symmetric
+            salt = ffi.new("byte[]", PBP_COMPAT_SALT)
+            symkey = libpcp.pcp_scrypt(self._ctx, passphrase, len(passphrase), salt, 90);
+            size =  libpcp.pcp_encrypt_stream_sym(self._ctx, instream._stream, outstream._stream, symkey, 0, ffi.NULL)
+
+            if size <= 0:
+                self.throw(IOError, "failed to encrypt")
+
+            return ffi.buffer(libpcp.buffer_get_remainder(outstream._stream.b), libpcp.buffer_size(outstream._stream.b))[:]