path: root/marshal.c

/* See LICENSE file for copyright and license details. */
#include "common.h"


size_t
libsha2_marshal(const struct libsha2_state *restrict state, void *restrict buf_)
{
	char *restrict buf = buf_;
	size_t off = 0;

	if (buf)
		*(int *)buf = 1; /* 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);

	if (state->algorithm <= 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->h.b32, sizeof(state->h.b32));
		off += sizeof(state->h.b32);
	} else {
		if (buf)
			memcpy(&buf[off], state->k.b64, sizeof(state->k.b64));
		off += sizeof(state->k.b64);
		if (buf)
			memcpy(&buf[off], state->h.b64, sizeof(state->h.b64));
		off += sizeof(state->h.b64);
	}

	if (buf)
		*(size_t *)&buf[off] = state->chunk_size;
	off += sizeof(size_t);
	if (buf)
		memcpy(&buf[off], state->chunk, (state->message_size / 8) % state->chunk_size);
	off += (state->message_size / 8) % state->chunk_size;

	return off;
}