First commit

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

1 files changed, 61 insertions, 0 deletions

diff --git a/digest.c b/digest.c
new file mode 100644
index 0000000..fd40e8f
--- /dev/null
+++ b/digest.c
@@ -0,0 +1,61 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+/**
+ * Absorb the last part of the message and output a hash
+ * 
+ * @param  state    The hashing state
+ * @param  message  The message, in bits
+ * @param  msglen   The length of the message, zero if there is nothing more to absorb
+ * @param  output   The output buffer for the hash
+ */
+void
+libsha1_digest(struct libsha1_state *restrict state, const void *message_, size_t msglen, void *output_)
+{
+	const char *message = message_;
+	unsigned char *output = output_;
+	size_t off, i, n;
+
+	if (msglen & ~(size_t)7) {
+		libsha1_update(state, message, msglen & ~(size_t)7);
+		message += msglen & ~(size_t)7;
+		msglen &= (size_t)7;
+	}
+
+	off = (state->message_size / 8) % state->chunk_size;
+	if (msglen) {
+		state->chunk[off] = (unsigned char)(*message << (8 - (int)msglen));
+		state->chunk[off] |= (unsigned char)(1 << (7 - msglen));
+		state->chunk[off] &= (unsigned char)~((1 << (7 - msglen)) - 1);
+		state->message_size += msglen;
+	} else {
+		state->chunk[off] = 0x80;
+	}
+	off += 1;
+
+	if (off > state->chunk_size - (size_t)8) {
+		memset(state->chunk + off, 0, state->chunk_size - off);
+		off = 0;
+		libsha1_process(state, state->chunk);
+	}
+
+	memset(state->chunk + off, 0, state->chunk_size - 8 - off);
+	state->chunk[state->chunk_size - 8] = (unsigned char)(state->message_size >> 56);
+	state->chunk[state->chunk_size - 7] = (unsigned char)(state->message_size >> 48);
+	state->chunk[state->chunk_size - 6] = (unsigned char)(state->message_size >> 40);
+	state->chunk[state->chunk_size - 5] = (unsigned char)(state->message_size >> 32);
+	state->chunk[state->chunk_size - 4] = (unsigned char)(state->message_size >> 24);
+	state->chunk[state->chunk_size - 3] = (unsigned char)(state->message_size >> 16);
+	state->chunk[state->chunk_size - 2] = (unsigned char)(state->message_size >>  8);
+	state->chunk[state->chunk_size - 1] = (unsigned char)(state->message_size >>  0);
+	libsha1_process(state, state->chunk);
+
+	n = libsha1_algorithm_output_size(state->algorithm);
+	for (i = 0, n /= 4; i < n; i++) {
+		output[4 * i + 0] = (unsigned char)(state->h[i] >> 24);
+		output[4 * i + 1] = (unsigned char)(state->h[i] >> 16);
+		output[4 * i + 2] = (unsigned char)(state->h[i] >>  8);
+		output[4 * i + 3] = (unsigned char)(state->h[i] >>  0);
+	}
+}