1 files changed, 66 insertions, 0 deletions
diff --git a/digest.c b/digest.c
new file mode 100644
index 0000000..8658388
--- /dev/null
+++ b/digest.c
@@ -0,0 +1,66 @@
+/* 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
+libsha2_digest(struct libsha2_state *restrict state, const char *restrict message, size_t msglen, char *output)
+{
+	char *appendix;
+	size_t i, j, k, n;
+
+	if (msglen & ~7) {
+		libsha2_update(state, message, msglen & ~7);
+		message += msglen & ~7;
+		msglen &= 7;
+	}
+
+	k = 8 * state->chunk_size;
+	n = state->chunk_size + 8;
+	n = (k + (n % k)) % k;
+	n = n / 8 - 1;
+
+	appendix = state->appendix;
+	if (msglen) {
+		j = 7 - msglen;
+		*appendix = *message;
+		*appendix |= 1 << j;
+		*appendix &= ~((1 << j) - 1);
+	} else {
+		*appendix = (unsigned char)128;
+	}
+
+	k = state->message_size + msglen;
+	i = state->chunk_size / 8;
+	appendix += n + i - 1;
+	for (i = i < sizeof(size_t) ? i : sizeof(size_t); i--;)
+		*(appendix - i) = (unsigned char)((k >> (i * 8)) & 255);
+
+	n += state->chunk_size;
+	libsha2_update(state, state->appendix, n);
+
+	n = libsha2_algorithm_output_size(state->algorithm);
+	switch (state->algorithm) {
+	case LIBSHA2_224:
+	case LIBSHA2_256:
+		for (i = 0; i < 8; i++)
+			for (j = 0; j < (state->chunk_size / 16); j++)
+				if (k = (i + 1) * (state->chunk_size / 16) - j - 1, k < n)
+					output[k] = (char)((state->h.b32[i] >> (8 * j)) & 255);
+		break;
+
+	default:
+		for (i = 0; i < 8; i++)
+			for (j = 0; j < (state->chunk_size / 16); j++)
+				if (k = (i + 1) * (state->chunk_size / 16) - j - 1, k < n)
+					output[k] = (char)((state->h.b64[i] >> (8 * j)) & 255);
+		break;
+	}
+}