1 files changed, 147 insertions, 0 deletions
diff --git a/source/blender/blenlib/intern/hash_mm3.c b/source/blender/blenlib/intern/hash_mm3.c
new file mode 100644
index 00000000000..105c1f46832
--- /dev/null
+++ b/source/blender/blenlib/intern/hash_mm3.c
@@ -0,0 +1,147 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ *
+ * Copyright (C) 2018 Blender Foundation.
+ *
+ */
+
+/** \file blender/blenlib/intern/hash_mm3.c
+ *  \ingroup bli
+ *
+ *  Functions to compute Murmur3 hash key.
+ *
+ * This Code is based on alShaders/Cryptomatte/MurmurHash3.h:
+ *
+ * MurmurHash3 was written by Austin Appleby, and is placed in the public
+ * domain. The author hereby disclaims copyright to this source code.
+ *
+ */
+
+#include "BLI_compiler_compat.h"
+#include "BLI_compiler_attrs.h"
+#include "BLI_hash_mm3.h"  /* own include */
+
+#if defined(_MSC_VER)
+#  include <stdlib.h>
+#  define ROTL32(x,y) _rotl(x,y)
+#  define BIG_CONSTANT(x) (x)
+
+/* Other compilers */
+#else	/* defined(_MSC_VER) */
+static inline uint32_t rotl32(uint32_t x, int8_t r)
+{
+	return (x << r) | (x >> (32 - r));
+}
+#  define ROTL32(x,y) rotl32(x,y)
+#  define BIG_CONSTANT(x) (x##LLU)
+#endif /* !defined(_MSC_VER) */
+
+/* Block read - if your platform needs to do endian-swapping or can only
+ * handle aligned reads, do the conversion here
+ */
+
+BLI_INLINE uint32_t getblock32(const uint32_t * p, int i)
+{
+	return p[i];
+}
+
+BLI_INLINE uint64_t getblock64(const uint64_t * p, int i)
+{
+	return p[i];
+}
+
+/* Finalization mix - force all bits of a hash block to avalanche */
+
+BLI_INLINE uint32_t fmix32(uint32_t h)
+{
+	h ^= h >> 16;
+	h *= 0x85ebca6b;
+	h ^= h >> 13;
+	h *= 0xc2b2ae35;
+	h ^= h >> 16;
+
+	return h;
+}
+
+BLI_INLINE uint64_t fmix64(uint64_t k)
+{
+	k ^= k >> 33;
+	k *= BIG_CONSTANT(0xff51afd7ed558ccd);
+	k ^= k >> 33;
+	k *= BIG_CONSTANT(0xc4ceb9fe1a85ec53);
+	k ^= k >> 33;
+
+	return k;
+}
+
+uint32_t BLI_hash_mm3(const unsigned char *in, size_t len, uint32_t seed)
+{
+	const uint8_t *data = (const uint8_t *)in;
+	const int nblocks = len / 4;
+
+	uint32_t h1 = seed;
+
+	const uint32_t c1 = 0xcc9e2d51;
+	const uint32_t c2 = 0x1b873593;
+
+	/* body */
+
+	const uint32_t *blocks = (const uint32_t *)(data + nblocks * 4);
+
+	for (int i = -nblocks; i; i++) {
+		uint32_t k1 = getblock32(blocks, i);
+
+		k1 *= c1;
+		k1 = ROTL32(k1, 15);
+		k1 *= c2;
+
+		h1 ^= k1;
+		h1 = ROTL32(h1, 13);
+		h1 = h1 * 5 + 0xe6546b64;
+	}
+
+	/* tail */
+
+	const uint8_t *tail = (const uint8_t *)(data + nblocks * 4);
+
+	uint32_t k1 = 0;
+
+	switch (len & 3) {
+		case 3:
+			k1 ^= tail[2] << 16;
+			ATTR_FALLTHROUGH;
+		case 2:
+			k1 ^= tail[1] << 8;
+			ATTR_FALLTHROUGH;
+		case 1:
+			k1 ^= tail[0];
+			k1 *= c1;
+			k1 = ROTL32(k1, 15);
+			k1 *= c2;
+			h1 ^= k1;
+	}
+
+	/* finalization */
+
+	h1 ^= len;
+
+	h1 = fmix32(h1);
+
+	return h1;
+}