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/* See LICENSE file for copyright and license details. */
#include "common.h"
/**
* Unmarshal a state from a buffer
*
* @param state Output parameter for the unmarshalled state
* @param buf The buffer from which the state shall be unmarshalled
* @param bufsize The maximum number of bytes that can be unmarshalled
* @return The number of read bytes, 0 on failure
*/
size_t
libsha1_unmarshal(struct libsha1_state *restrict state, const void *restrict buf_, size_t bufsize)
{
const char *restrict buf = buf_;
size_t off = 0;
if (bufsize < sizeof(int) + sizeof(enum libsha1_algorithm) + sizeof(size_t)) {
errno = EINVAL;
return 0;
}
if (*(const int *)buf) { /* version */
errno = EINVAL;
return 0;
}
off += sizeof(int);
state->algorithm = *(const enum libsha1_algorithm *)&buf[off];
off += sizeof(enum libsha1_algorithm);
state->message_size = *(const size_t *)&buf[off];
off += sizeof(size_t);
if (bufsize - off < sizeof(state->w) + sizeof(state->h)) {
errno = EINVAL;
return 0;
}
memcpy(state->w, &buf[off], sizeof(state->w));
off += sizeof(state->w);
memcpy(state->h, &buf[off], sizeof(state->h));
off += sizeof(state->h);
if (bufsize - off < (state->message_size / 8) % sizeof(state->chunk)) {
errno = EINVAL;
return 0;
}
memcpy(state->chunk, &buf[off], (state->message_size / 8) % sizeof(state->chunk));
off += (state->message_size / 8) % sizeof(state->chunk);
return off;
}
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