Add marshal and unmarshal functions

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 62 insertions, 0 deletions

diff --git a/marshal.c b/marshal.c
new file mode 100644
index 0000000..21f0f79
--- /dev/null
+++ b/marshal.c
@@ -0,0 +1,62 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+/**
+ * Marshal a state into a buffer
+ * 
+ * @param   state  The state to marshal
+ * @param   buf    Output buffer, `NULL` to only return the required size
+ * @return         The number of bytes marshalled to `buf`
+ */
+size_t
+libsha2_marshal(const struct libsha2_state *restrict state, char *restrict buf)
+{
+	size_t off = 0;
+
+	if (buf)
+		*(int *)buf = 0; /* version */
+	off += sizeof(int);
+	if (buf)
+		*(enum libsha2_algorithm *)&buf[off] = state->algorithm;
+	off += sizeof(enum libsha2_algorithm);
+	if (buf)
+		*(size_t *)&buf[off] = state->message_size;
+	off += sizeof(size_t);
+
+	switch (state->algorithm) {
+	case LIBSHA2_224:
+	case LIBSHA2_256:
+		if (buf)
+			memcpy(&buf[off], state->k.b32, sizeof(state->k.b32));
+		off += sizeof(state->k.b32);
+		if (buf)
+			memcpy(&buf[off], state->w.b32, sizeof(state->w.b32));
+		off += sizeof(state->w.b32);
+		if (buf)
+			memcpy(&buf[off], state->h.b32, sizeof(state->h.b32));
+		off += sizeof(state->h.b32);
+		break;
+
+	default:
+		if (buf)
+			memcpy(&buf[off], state->k.b64, sizeof(state->k.b64));
+		off += sizeof(state->k.b64);
+		if (buf)
+			memcpy(&buf[off], state->w.b64, sizeof(state->w.b64));
+		off += sizeof(state->w.b64);
+		if (buf)
+			memcpy(&buf[off], state->h.b64, sizeof(state->h.b64));
+		off += sizeof(state->h.b64);
+		break;
+	}
+
+	if (buf)
+		memcpy(&buf[off], state->chunk, sizeof(state->chunk));
+	off += sizeof(state->chunk);
+	if (buf)
+		*(size_t *)&buf[off] = state->chunk_size;
+	off += sizeof(size_t);
+
+	return off;
+}