Change license to ISC and reorganise

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

1 files changed, 140 insertions, 0 deletions

diff --git a/update.c b/update.c
new file mode 100644
index 0000000..26eceb8
--- /dev/null
+++ b/update.c
@@ -0,0 +1,140 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+/**
+ * Unified implementation (what can unified without performance impact)
+ * of the chunk processing for all SHA-2 functions
+ * 
+ * @param  A       Wordsize-dependent constant, take a look at the code
+ * @param  B       Wordsize-dependent constant, take a look at the code
+ * @param  C       Wordsize-dependent constant, take a look at the code
+ * @param  D       Wordsize-dependent constant, take a look at the code
+ * @param  E       Wordsize-dependent constant, take a look at the code
+ * @param  F       Wordsize-dependent constant, take a look at the code
+ * @param  G       Wordsize-dependent constant, take a look at the code
+ * @param  H       Wordsize-dependent constant, take a look at the code
+ * @param  I       Wordsize-dependent constant, take a look at the code
+ * @param  J       Wordsize-dependent constant, take a look at the code
+ * @param  K       Wordsize-dependent constant, take a look at the code
+ * @param  L       Wordsize-dependent constant, take a look at the code
+ * @param  WORD_T  `__typeof()` on any wordsize-dependent variable, with exact size
+ * @param  k       Round constants
+ * @param  w       Words
+ * @param  h       Hash values
+ * @param  work_h  Space for temporary hash values
+ */
+#define SHA2_IMPLEMENTATION(A, B, C, D, E, F, G, H, I, J, K, L, WORD_T, k, w, h, work_h)\
+	memcpy(work_h, h, sizeof(work_h));\
+	\
+	memset(w, 0, 16 * sizeof(*(w)));\
+	for (i = 0; i < 16; i++)\
+		for (j = 0; j < sizeof(WORD_T); j++)\
+			w[i] |= ((WORD_T)(state->chunk[(i + 1) * sizeof(WORD_T) - j - 1])) << (j << 3);\
+	\
+	for (i = 16; i < sizeof(k) / sizeof(*(k)); i++)	{\
+		w[i] = w[i - 16] + w[i - 7];\
+		w[i] += ROTR(w[i - 15], A) ^ ROTR(w[i - 15], B) ^ (w[i - 15] >> (C));\
+		w[i] += ROTR(w[i - 2], D) ^ ROTR(w[i - 2], E) ^ (w[i - 2] >> (F));\
+	}\
+	\
+	for (i = 0; i < sizeof(k) / sizeof(*(k)); i++) {\
+		s1 = (work_h[4] & work_h[5]) ^ (work_h[6] & ~(work_h[4]));\
+		s1 += work_h[7] + k[i] + w[i];\
+		s0 = (work_h[0] & work_h[1]) ^ (work_h[0] & work_h[2]) ^ (work_h[1] & work_h[2]);\
+		s1 += ROTR(work_h[4], G) ^ ROTR(work_h[4], H) ^ ROTR(work_h[4], I);\
+		s0 += ROTR(work_h[0], J) ^ ROTR(work_h[0], K) ^ ROTR(work_h[0], L);\
+		\
+		memmove(work_h + 1, work_h, 7 * sizeof(*(work_h)));\
+		work_h[4] += s1;\
+		work_h[0] = s1 + s0;\
+	}\
+	\
+	for (i = 0; i < 8; i++)\
+		h[i] += work_h[i]
+
+
+/**
+ * Process a chunk using SHA-256
+ * 
+ * @param  state  The hashing state
+ */
+#if defined(__GNUC__)
+__attribute__((__nonnull__, __nothrow__))
+#endif
+static void
+process256(struct libsha2_state *restrict state)
+{
+	uint32_t s0, s1;
+	size_t i, j;
+#if defined(__GNUC__)
+# pragma GCC diagnostic push
+# pragma GCC diagnostic ignored "-Wmemset-elt-size"
+#endif
+#define ROTR(X, N) (((X) >> (N)) | ((X) << ((sizeof(uint32_t) * 8) - (N))))
+	SHA2_IMPLEMENTATION(7, 18, 3, 17, 19, 10, 6, 11, 25, 2, 13, 22, uint32_t,
+	                    state->k.b32, state->w.b32, state->h.b32, state->work_h.b32);
+#undef ROTR
+#if defined(__GNUC__)
+# pragma GCC diagnostic pop
+#endif
+}
+
+
+/**
+ * Process a chunk using SHA-512
+ * 
+ * @param  state  The hashing state
+ */
+#if defined(__GNUC__)
+__attribute__((__nonnull__, __nothrow__))
+#endif
+static void
+process512(struct libsha2_state *restrict state)
+{
+	uint64_t s0, s1;
+	size_t i, j;
+#define ROTR(X, N) (((X) >> (N)) | ((X) << ((sizeof(uint64_t) * 8) - (N))))
+	SHA2_IMPLEMENTATION(1, 8, 7, 19, 61, 6, 14, 18, 41, 28, 34, 39, uint64_t,
+	                    state->k.b64, state->w.b64, state->h.b64, state->work_h.b64);
+#undef ROTR
+}
+
+
+/**
+ * Absorb more of the message
+ * 
+ * @param  state    The hashing state
+ * @param  message  The message, in bits, must be equivalent to 0 modulus 8
+ * @param  msglen   The length of the message
+ */
+void
+libsha2_update(struct libsha2_state *restrict state, const char *restrict message, size_t msglen)
+{
+	size_t n, off, mlen;
+
+	msglen /= 8;
+	mlen = state->message_size / 8;
+
+	while (msglen) {
+		off = mlen % state->chunk_size;
+		n = state->chunk_size - off;
+		n = n < msglen ? n : msglen;
+		memcpy(state->chunk + off, message, n);
+		if (off + n == state->chunk_size) {
+			switch (state->algorithm) {
+			case LIBSHA2_224:
+			case LIBSHA2_256:
+				process256(state);
+				break;
+
+			default:
+				process512(state);
+				break;
+			}
+		}
+		message += n, mlen += n, msglen -= n;
+	}
+
+	state->message_size = mlen * 8;
+}