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Add SpookyHashV2-based hash to StringPiece

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Summary: Since the old one is weak and slow.

Test Plan: Unit tests

Reviewed By: ott@fb.com

Subscribers: trunkagent, maxime, folly-diffs@, yfeldblum, chalfant

FB internal diff: D2052630

Tasks: 6998080

Signature: t1:2052630:1431015271:bc90ccf99941902cd4bd43a0980238c616e66abf
This commit is contained in:
Tom Jackson
2015-05-08 00:43:26 -07:00
committed by Praveen Kumar Ramakrishnan
parent 675a137da2
commit 5cc2f9945c
3 changed files with 47 additions and 0 deletions
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folly/Hash.h
+7
View File
@@ -338,6 +338,13 @@ inline uint32_t hsieh_hash32_str(const std::string& str) {
template<class Key>
struct hasher;
struct Hash {
template <class T>
size_t operator()(const T& v) const {
return hasher<T>()(v);
}
};
template<> struct hasher<int32_t> {
size_t operator()(int32_t key) const {
return hash::jenkins_rev_mix32(uint32_t(key));
folly/Range.h
+12
View File
@@ -22,6 +22,8 @@
#include <folly/Portability.h>
#include <folly/FBString.h>
#include <folly/SpookyHashV2.h>
#include <algorithm>
#include <boost/operators.hpp>
#include <climits>
@@ -1121,6 +1123,16 @@ inline size_t qfind_first_of(const Range<const unsigned char*>& haystack,
return detail::qfind_first_byte_of(StringPiece(haystack),
StringPiece(needles));
}
template<class Key>
struct hasher;
template <class T> struct hasher<folly::Range<T*>> {
size_t operator()(folly::Range<T*> r) const {
return hash::SpookyHashV2::Hash64(r.begin(), r.size() * sizeof(T), 0);
}
};
} // !namespace folly
#pragma GCC diagnostic pop
folly/test/HashTest.cpp
+28
View File
@@ -262,3 +262,31 @@ TEST(Hash, std_tuple_different_hash) {
EXPECT_NE(std::hash<tuple3>()(t1),
std::hash<tuple3>()(t3));
}
TEST(Range, Hash) {
using namespace folly;
StringPiece a1 = "10050517", b1 = "51107032",
a2 = "10050518", b2 = "51107033",
a3 = "10050519", b3 = "51107034",
a4 = "10050525", b4 = "51107040";
Range<const wchar_t*> w1 = range(L"10050517"), w2 = range(L"51107032"),
w3 = range(L"10050518"), w4 = range(L"51107033");
StringPieceHash h1;
Hash h2;
EXPECT_EQ(h1(a1), h1(b1));
EXPECT_EQ(h1(a2), h1(b2));
EXPECT_EQ(h1(a3), h1(b3));
EXPECT_EQ(h1(a4), h1(b4));
EXPECT_NE(h2(a1), h2(b1));
EXPECT_NE(h2(a1), h2(b1));
EXPECT_NE(h2(a2), h2(b2));
EXPECT_NE(h2(a3), h2(b3));
EXPECT_NE(h2(ByteRange(a1)), h2(ByteRange(b1)));
EXPECT_NE(h2(ByteRange(a2)), h2(ByteRange(b2)));
EXPECT_NE(h2(ByteRange(a3)), h2(ByteRange(b3)));
EXPECT_NE(h2(ByteRange(a4)), h2(ByteRange(b4)));
EXPECT_NE(h2(w1), h2(w2));
EXPECT_NE(h2(w1), h2(w3));
EXPECT_NE(h2(w2), h2(w4));
}