+#include "unaligned.h"
+
+static inline uint64_t rotate_left(uint64_t x, uint8_t b) {
+ assert(b < 64);
+
+ return (x << b) | (x >> (64 - b));
+}
+
+static inline void sipround(struct siphash *state) {
+ assert(state);
+
+ state->v0 += state->v1;
+ state->v1 = rotate_left(state->v1, 13);
+ state->v1 ^= state->v0;
+ state->v0 = rotate_left(state->v0, 32);
+ state->v2 += state->v3;
+ state->v3 = rotate_left(state->v3, 16);
+ state->v3 ^= state->v2;
+ state->v0 += state->v3;
+ state->v3 = rotate_left(state->v3, 21);
+ state->v3 ^= state->v0;
+ state->v2 += state->v1;
+ state->v1 = rotate_left(state->v1, 17);
+ state->v1 ^= state->v2;
+ state->v2 = rotate_left(state->v2, 32);
+}
+
+void siphash24_init(struct siphash *state, const uint8_t k[16]) {
+ uint64_t k0, k1;
+
+ assert(state);
+ assert(k);
+
+ k0 = unaligned_read_le64(k);
+ k1 = unaligned_read_le64(k + 8);
+
+ *state = (struct siphash) {
+ /* "somepseudorandomlygeneratedbytes" */
+ .v0 = 0x736f6d6570736575ULL ^ k0,
+ .v1 = 0x646f72616e646f6dULL ^ k1,
+ .v2 = 0x6c7967656e657261ULL ^ k0,
+ .v3 = 0x7465646279746573ULL ^ k1,
+ .padding = 0,
+ .inlen = 0,
+ };
+}
+
+void siphash24_compress(const void *_in, size_t inlen, struct siphash *state) {
+
+ const uint8_t *in = _in;
+ const uint8_t *end = in + inlen;
+ size_t left = state->inlen & 7;
+ uint64_t m;
+
+ assert(in);
+ assert(state);
+
+ /* Update total length */
+ state->inlen += inlen;
+
+ /* If padding exists, fill it out */
+ if (left > 0) {
+ for ( ; in < end && left < 8; in ++, left ++)
+ state->padding |= ((uint64_t) *in) << (left * 8);
+
+ if (in == end && left < 8)
+ /* We did not have enough input to fill out the padding completely */
+ return;