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, 92 insertions, 0 deletions

diff --git a/src/pickle_encoding.c b/src/pickle_encoding.c
new file mode 100644
index 0000000..5d5f8d7
--- /dev/null
+++ b/src/pickle_encoding.c
@@ -0,0 +1,92 @@
+/* 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.
+ */
+
+#include "olm/pickle_encoding.h"
+
+#include "olm/base64.h"
+#include "olm/cipher.h"
+#include "olm/olm.h"
+
+static const struct _olm_cipher_aes_sha_256 PICKLE_CIPHER =
+    OLM_CIPHER_INIT_AES_SHA_256("Pickle");
+
+size_t _olm_enc_output_length(
+    size_t raw_length
+) {
+    const struct _olm_cipher *cipher = OLM_CIPHER_BASE(&PICKLE_CIPHER);
+    size_t length = cipher->ops->encrypt_ciphertext_length(cipher, raw_length);
+    length += cipher->ops->mac_length(cipher);
+    return _olm_encode_base64_length(length);
+}
+
+uint8_t * _olm_enc_output_pos(
+    uint8_t * output,
+    size_t raw_length
+) {
+    const struct _olm_cipher *cipher = OLM_CIPHER_BASE(&PICKLE_CIPHER);
+    size_t length = cipher->ops->encrypt_ciphertext_length(cipher, raw_length);
+    length += cipher->ops->mac_length(cipher);
+    return output + _olm_encode_base64_length(length) - length;
+}
+
+size_t _olm_enc_output(
+    uint8_t const * key, size_t key_length,
+    uint8_t * output, size_t raw_length
+) {
+    const struct _olm_cipher *cipher = OLM_CIPHER_BASE(&PICKLE_CIPHER);
+    size_t ciphertext_length = cipher->ops->encrypt_ciphertext_length(
+        cipher, raw_length
+    );
+    size_t length = ciphertext_length + cipher->ops->mac_length(cipher);
+    size_t base64_length = _olm_encode_base64_length(length);
+    uint8_t * raw_output = output + base64_length - length;
+    cipher->ops->encrypt(
+        cipher,
+        key, key_length,
+        raw_output, raw_length,
+        raw_output, ciphertext_length,
+        raw_output, length
+    );
+    _olm_encode_base64(raw_output, length, output);
+    return raw_length;
+}
+
+
+size_t _olm_enc_input(uint8_t const * key, size_t key_length,
+                      uint8_t * input, size_t b64_length,
+                      enum OlmErrorCode * last_error
+) {
+    size_t enc_length = _olm_decode_base64_length(b64_length);
+    if (enc_length == (size_t)-1) {
+        if (last_error) {
+            *last_error = OLM_INVALID_BASE64;
+        }
+        return (size_t)-1;
+    }
+    _olm_decode_base64(input, b64_length, input);
+    const struct _olm_cipher *cipher = OLM_CIPHER_BASE(&PICKLE_CIPHER);
+    size_t raw_length = enc_length - cipher->ops->mac_length(cipher);
+    size_t result = cipher->ops->decrypt(
+        cipher,
+        key, key_length,
+        input, enc_length,
+        input, raw_length,
+        input, raw_length
+    );
+    if (result == (size_t)-1 && last_error) {
+        *last_error = OLM_BAD_ACCOUNT_KEY;
+    }
+    return result;
+}