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authorPéter Szilágyi <peterke@gmail.com>2018-11-13 00:47:34 +0800
committerPéter Szilágyi <peterke@gmail.com>2018-11-15 18:22:13 +0800
commit434dd5bc0067cdf604d84426df9086015721dd36 (patch)
tree279d85e32a36b8804d60c5a4b83b444514850782 /vendor/github.com/allegro/bigcache/fnv.go
parent9a000601c6c4e4f8134caedba1957ffe28d2b659 (diff)
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cmd, core, eth, light, trie: add trie read caching layer
Diffstat (limited to 'vendor/github.com/allegro/bigcache/fnv.go')
-rw-r--r--vendor/github.com/allegro/bigcache/fnv.go28
1 files changed, 28 insertions, 0 deletions
diff --git a/vendor/github.com/allegro/bigcache/fnv.go b/vendor/github.com/allegro/bigcache/fnv.go
new file mode 100644
index 000000000..188c9aa6d
--- /dev/null
+++ b/vendor/github.com/allegro/bigcache/fnv.go
@@ -0,0 +1,28 @@
+package bigcache
+
+// newDefaultHasher returns a new 64-bit FNV-1a Hasher which makes no memory allocations.
+// Its Sum64 method will lay the value out in big-endian byte order.
+// See https://en.wikipedia.org/wiki/Fowler–Noll–Vo_hash_function
+func newDefaultHasher() Hasher {
+ return fnv64a{}
+}
+
+type fnv64a struct{}
+
+const (
+ // offset64 FNVa offset basis. See https://en.wikipedia.org/wiki/Fowler–Noll–Vo_hash_function#FNV-1a_hash
+ offset64 = 14695981039346656037
+ // prime64 FNVa prime value. See https://en.wikipedia.org/wiki/Fowler–Noll–Vo_hash_function#FNV-1a_hash
+ prime64 = 1099511628211
+)
+
+// Sum64 gets the string and returns its uint64 hash value.
+func (f fnv64a) Sum64(key string) uint64 {
+ var hash uint64 = offset64
+ for i := 0; i < len(key); i++ {
+ hash ^= uint64(key[i])
+ hash *= prime64
+ }
+
+ return hash
+}