initial code repo

[stor4nfv.git] / src / ceph / src / crush / hash.c

diff --git a/src/ceph/src/crush/hash.c b/src/ceph/src/crush/hash.c
new file mode 100644 (file)
index 0000000..ed123af
--- /dev/null
+++ b/src/ceph/src/crush/hash.c
@@ -0,0 +1,151 @@
+#ifdef __KERNEL__
+# include <linux/crush/hash.h>
+#else
+# include "hash.h"
+#endif
+
+/*
+ * Robert Jenkins' function for mixing 32-bit values
+ * http://burtleburtle.net/bob/hash/evahash.html
+ * a, b = random bits, c = input and output
+ */
+#define crush_hashmix(a, b, c) do {                    \
+               a = a-b;  a = a-c;  a = a^(c>>13);      \
+               b = b-c;  b = b-a;  b = b^(a<<8);       \
+               c = c-a;  c = c-b;  c = c^(b>>13);      \
+               a = a-b;  a = a-c;  a = a^(c>>12);      \
+               b = b-c;  b = b-a;  b = b^(a<<16);      \
+               c = c-a;  c = c-b;  c = c^(b>>5);       \
+               a = a-b;  a = a-c;  a = a^(c>>3);       \
+               b = b-c;  b = b-a;  b = b^(a<<10);      \
+               c = c-a;  c = c-b;  c = c^(b>>15);      \
+       } while (0)
+
+#define crush_hash_seed 1315423911
+
+static __u32 crush_hash32_rjenkins1(__u32 a)
+{
+       __u32 hash = crush_hash_seed ^ a;
+       __u32 b = a;
+       __u32 x = 231232;
+       __u32 y = 1232;
+       crush_hashmix(b, x, hash);
+       crush_hashmix(y, a, hash);
+       return hash;
+}
+
+static __u32 crush_hash32_rjenkins1_2(__u32 a, __u32 b)
+{
+       __u32 hash = crush_hash_seed ^ a ^ b;
+       __u32 x = 231232;
+       __u32 y = 1232;
+       crush_hashmix(a, b, hash);
+       crush_hashmix(x, a, hash);
+       crush_hashmix(b, y, hash);
+       return hash;
+}
+
+static __u32 crush_hash32_rjenkins1_3(__u32 a, __u32 b, __u32 c)
+{
+       __u32 hash = crush_hash_seed ^ a ^ b ^ c;
+       __u32 x = 231232;
+       __u32 y = 1232;
+       crush_hashmix(a, b, hash);
+       crush_hashmix(c, x, hash);
+       crush_hashmix(y, a, hash);
+       crush_hashmix(b, x, hash);
+       crush_hashmix(y, c, hash);
+       return hash;
+}
+
+static __u32 crush_hash32_rjenkins1_4(__u32 a, __u32 b, __u32 c, __u32 d)
+{
+       __u32 hash = crush_hash_seed ^ a ^ b ^ c ^ d;
+       __u32 x = 231232;
+       __u32 y = 1232;
+       crush_hashmix(a, b, hash);
+       crush_hashmix(c, d, hash);
+       crush_hashmix(a, x, hash);
+       crush_hashmix(y, b, hash);
+       crush_hashmix(c, x, hash);
+       crush_hashmix(y, d, hash);
+       return hash;
+}
+
+static __u32 crush_hash32_rjenkins1_5(__u32 a, __u32 b, __u32 c, __u32 d,
+                                     __u32 e)
+{
+       __u32 hash = crush_hash_seed ^ a ^ b ^ c ^ d ^ e;
+       __u32 x = 231232;
+       __u32 y = 1232;
+       crush_hashmix(a, b, hash);
+       crush_hashmix(c, d, hash);
+       crush_hashmix(e, x, hash);
+       crush_hashmix(y, a, hash);
+       crush_hashmix(b, x, hash);
+       crush_hashmix(y, c, hash);
+       crush_hashmix(d, x, hash);
+       crush_hashmix(y, e, hash);
+       return hash;
+}
+
+
+__u32 crush_hash32(int type, __u32 a)
+{
+       switch (type) {
+       case CRUSH_HASH_RJENKINS1:
+               return crush_hash32_rjenkins1(a);
+       default:
+               return 0;
+       }
+}
+
+__u32 crush_hash32_2(int type, __u32 a, __u32 b)
+{
+       switch (type) {
+       case CRUSH_HASH_RJENKINS1:
+               return crush_hash32_rjenkins1_2(a, b);
+       default:
+               return 0;
+       }
+}
+
+__u32 crush_hash32_3(int type, __u32 a, __u32 b, __u32 c)
+{
+       switch (type) {
+       case CRUSH_HASH_RJENKINS1:
+               return crush_hash32_rjenkins1_3(a, b, c);
+       default:
+               return 0;
+       }
+}
+
+__u32 crush_hash32_4(int type, __u32 a, __u32 b, __u32 c, __u32 d)
+{
+       switch (type) {
+       case CRUSH_HASH_RJENKINS1:
+               return crush_hash32_rjenkins1_4(a, b, c, d);
+       default:
+               return 0;
+       }
+}
+
+__u32 crush_hash32_5(int type, __u32 a, __u32 b, __u32 c, __u32 d, __u32 e)
+{
+       switch (type) {
+       case CRUSH_HASH_RJENKINS1:
+               return crush_hash32_rjenkins1_5(a, b, c, d, e);
+       default:
+               return 0;
+       }
+}
+
+const char *crush_hash_name(int type)
+{
+       switch (type) {
+       case CRUSH_HASH_RJENKINS1:
+               return "rjenkins1";
+       default:
+               return "unknown";
+       }
+}