Factor out pickle_encoding from olm.cpp

We don't need to have all of the top-level pickling functions in olm.cpp;
factor out the utilities to support it to pickle_encoding.cpp (and make sure
that they have plain-C bindings).

1 files changed, 76 insertions, 0 deletions

diff --git a/include/olm/pickle_encoding.h b/include/olm/pickle_encoding.h
new file mode 100644
index 0000000..03611df
--- /dev/null
+++ b/include/olm/pickle_encoding.h
@@ -0,0 +1,76 @@
+/* Copyright 2016 OpenMarket Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* functions for encrypting and decrypting pickled representations of objects */
+
+#ifndef OLM_PICKLE_ENCODING_H_
+#define OLM_PICKLE_ENCODING_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include "olm/error.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+/**
+ * Get the number of bytes needed to encode a pickle of the length given
+ */
+size_t _olm_enc_output_length(size_t raw_length);
+
+/**
+ * Get the point in the output buffer that the raw pickle should be written to.
+ *
+ * In order that we can use the same buffer for the raw pickle, and the encoded
+ * pickle, the raw pickle needs to be written at the end of the buffer. (The
+ * base-64 encoding would otherwise overwrite the end of the input before it
+ * was encoded.)
+ */
+ uint8_t *_olm_enc_output_pos(uint8_t * output, size_t raw_length);
+
+/**
+ * Encrypt and encode the given pickle in-situ.
+ *
+ * The raw pickle should have been written to enc_output_pos(pickle,
+ * raw_length).
+ *
+ * Returns the number of bytes in the encoded pickle.
+ */
+size_t _olm_enc_output(
+    uint8_t const * key, size_t key_length,
+    uint8_t *pickle, size_t raw_length
+);
+
+/**
+ * Decode and decrypt the given pickle in-situ.
+ *
+ * Returns the number of bytes in the decoded pickle, or olm_error() on error,
+ * in which case *last_error will be updated, if last_error is non-NULL.
+ */
+size_t _olm_enc_input(
+    uint8_t const * key, size_t key_length,
+    uint8_t * input, size_t b64_length,
+    enum OlmErrorCode * last_error
+);
+
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+#endif /* OLM_PICKLE_ENCODING_H_ */