1 files changed, 33 insertions, 0 deletions
diff --git a/hmac_digest.c b/hmac_digest.c
new file mode 100644
index 0000000..4acb1a1
--- /dev/null
+++ b/hmac_digest.c
@@ -0,0 +1,33 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+/**
+ * Feed data into the HMAC algorithm and
+ * get the result
+ * 
+ * The state of the algorithm will be reset and
+ * `libsha1_hmac_update` and `libsha1_hmac_update`
+ * can be called again
+ * 
+ * @param  state   The state of the algorithm
+ * @param  data    Data to feed into the algorithm
+ * @param  n       The number of bytes to feed into the algorithm
+ * @param  output  The output buffer for the hash, it will be as
+ *                 large as for the underlaying hash algorithm
+ */
+void
+libsha1_hmac_digest(struct libsha1_hmac_state *restrict state, const void *data, size_t n, void *output)
+{
+	if (!state->inited) {
+		libsha1_init(&state->sha1_state, state->sha1_state.algorithm);
+		libsha1_update(&state->sha1_state, state->ipad, state->sha1_state.chunk_size * 8);
+	}
+
+	libsha1_digest(&state->sha1_state, data, n, output);
+	libsha1_init(&state->sha1_state, state->sha1_state.algorithm);
+
+	libsha1_update(&state->sha1_state, state->opad, state->sha1_state.chunk_size * 8);
+	libsha1_digest(&state->sha1_state, output, state->outsize, output);
+	state->inited = 0;
+}