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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-16 19:23:18 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-16 19:23:18 +0000 |
commit | 43a123c1ae6613b3efeed291fa552ecd909d3acf (patch) | |
tree | fd92518b7024bc74031f78a1cf9e454b65e73665 /src/hash/maphash/maphash_test.go | |
parent | Initial commit. (diff) | |
download | golang-1.20-43a123c1ae6613b3efeed291fa552ecd909d3acf.tar.xz golang-1.20-43a123c1ae6613b3efeed291fa552ecd909d3acf.zip |
Adding upstream version 1.20.14.upstream/1.20.14upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/hash/maphash/maphash_test.go')
-rw-r--r-- | src/hash/maphash/maphash_test.go | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/src/hash/maphash/maphash_test.go b/src/hash/maphash/maphash_test.go new file mode 100644 index 0000000..7526989 --- /dev/null +++ b/src/hash/maphash/maphash_test.go @@ -0,0 +1,255 @@ +// Copyright 2019 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package maphash + +import ( + "bytes" + "fmt" + "hash" + "testing" +) + +func TestUnseededHash(t *testing.T) { + m := map[uint64]struct{}{} + for i := 0; i < 1000; i++ { + h := new(Hash) + m[h.Sum64()] = struct{}{} + } + if len(m) < 900 { + t.Errorf("empty hash not sufficiently random: got %d, want 1000", len(m)) + } +} + +func TestSeededHash(t *testing.T) { + s := MakeSeed() + m := map[uint64]struct{}{} + for i := 0; i < 1000; i++ { + h := new(Hash) + h.SetSeed(s) + m[h.Sum64()] = struct{}{} + } + if len(m) != 1 { + t.Errorf("seeded hash is random: got %d, want 1", len(m)) + } +} + +func TestHashGrouping(t *testing.T) { + b := bytes.Repeat([]byte("foo"), 100) + hh := make([]*Hash, 7) + for i := range hh { + hh[i] = new(Hash) + } + for _, h := range hh[1:] { + h.SetSeed(hh[0].Seed()) + } + hh[0].Write(b) + hh[1].WriteString(string(b)) + + writeByte := func(h *Hash, b byte) { + err := h.WriteByte(b) + if err != nil { + t.Fatalf("WriteByte: %v", err) + } + } + writeSingleByte := func(h *Hash, b byte) { + _, err := h.Write([]byte{b}) + if err != nil { + t.Fatalf("Write single byte: %v", err) + } + } + writeStringSingleByte := func(h *Hash, b byte) { + _, err := h.WriteString(string([]byte{b})) + if err != nil { + t.Fatalf("WriteString single byte: %v", err) + } + } + + for i, x := range b { + writeByte(hh[2], x) + writeSingleByte(hh[3], x) + if i == 0 { + writeByte(hh[4], x) + } else { + writeSingleByte(hh[4], x) + } + writeStringSingleByte(hh[5], x) + if i == 0 { + writeByte(hh[6], x) + } else { + writeStringSingleByte(hh[6], x) + } + } + + sum := hh[0].Sum64() + for i, h := range hh { + if sum != h.Sum64() { + t.Errorf("hash %d not identical to a single Write", i) + } + } + + if sum1 := Bytes(hh[0].Seed(), b); sum1 != hh[0].Sum64() { + t.Errorf("hash using Bytes not identical to a single Write") + } + + if sum1 := String(hh[0].Seed(), string(b)); sum1 != hh[0].Sum64() { + t.Errorf("hash using String not identical to a single Write") + } +} + +func TestHashBytesVsString(t *testing.T) { + s := "foo" + b := []byte(s) + h1 := new(Hash) + h2 := new(Hash) + h2.SetSeed(h1.Seed()) + n1, err1 := h1.WriteString(s) + if n1 != len(s) || err1 != nil { + t.Fatalf("WriteString(s) = %d, %v, want %d, nil", n1, err1, len(s)) + } + n2, err2 := h2.Write(b) + if n2 != len(b) || err2 != nil { + t.Fatalf("Write(b) = %d, %v, want %d, nil", n2, err2, len(b)) + } + if h1.Sum64() != h2.Sum64() { + t.Errorf("hash of string and bytes not identical") + } +} + +func TestHashHighBytes(t *testing.T) { + // See issue 34925. + const N = 10 + m := map[uint64]struct{}{} + for i := 0; i < N; i++ { + h := new(Hash) + h.WriteString("foo") + m[h.Sum64()>>32] = struct{}{} + } + if len(m) < N/2 { + t.Errorf("from %d seeds, wanted at least %d different hashes; got %d", N, N/2, len(m)) + } +} + +func TestRepeat(t *testing.T) { + h1 := new(Hash) + h1.WriteString("testing") + sum1 := h1.Sum64() + + h1.Reset() + h1.WriteString("testing") + sum2 := h1.Sum64() + + if sum1 != sum2 { + t.Errorf("different sum after reseting: %#x != %#x", sum1, sum2) + } + + h2 := new(Hash) + h2.SetSeed(h1.Seed()) + h2.WriteString("testing") + sum3 := h2.Sum64() + + if sum1 != sum3 { + t.Errorf("different sum on the same seed: %#x != %#x", sum1, sum3) + } +} + +func TestSeedFromSum64(t *testing.T) { + h1 := new(Hash) + h1.WriteString("foo") + x := h1.Sum64() // seed generated here + h2 := new(Hash) + h2.SetSeed(h1.Seed()) + h2.WriteString("foo") + y := h2.Sum64() + if x != y { + t.Errorf("hashes don't match: want %x, got %x", x, y) + } +} + +func TestSeedFromSeed(t *testing.T) { + h1 := new(Hash) + h1.WriteString("foo") + _ = h1.Seed() // seed generated here + x := h1.Sum64() + h2 := new(Hash) + h2.SetSeed(h1.Seed()) + h2.WriteString("foo") + y := h2.Sum64() + if x != y { + t.Errorf("hashes don't match: want %x, got %x", x, y) + } +} + +func TestSeedFromFlush(t *testing.T) { + b := make([]byte, 65) + h1 := new(Hash) + h1.Write(b) // seed generated here + x := h1.Sum64() + h2 := new(Hash) + h2.SetSeed(h1.Seed()) + h2.Write(b) + y := h2.Sum64() + if x != y { + t.Errorf("hashes don't match: want %x, got %x", x, y) + } +} + +func TestSeedFromReset(t *testing.T) { + h1 := new(Hash) + h1.WriteString("foo") + h1.Reset() // seed generated here + h1.WriteString("foo") + x := h1.Sum64() + h2 := new(Hash) + h2.SetSeed(h1.Seed()) + h2.WriteString("foo") + y := h2.Sum64() + if x != y { + t.Errorf("hashes don't match: want %x, got %x", x, y) + } +} + +// Make sure a Hash implements the hash.Hash and hash.Hash64 interfaces. +var _ hash.Hash = &Hash{} +var _ hash.Hash64 = &Hash{} + +func benchmarkSize(b *testing.B, size int) { + h := &Hash{} + buf := make([]byte, size) + s := string(buf) + + b.Run("Write", func(b *testing.B) { + b.SetBytes(int64(size)) + for i := 0; i < b.N; i++ { + h.Reset() + h.Write(buf) + h.Sum64() + } + }) + + b.Run("Bytes", func(b *testing.B) { + b.SetBytes(int64(size)) + seed := h.Seed() + for i := 0; i < b.N; i++ { + Bytes(seed, buf) + } + }) + + b.Run("String", func(b *testing.B) { + b.SetBytes(int64(size)) + seed := h.Seed() + for i := 0; i < b.N; i++ { + String(seed, s) + } + }) +} + +func BenchmarkHash(b *testing.B) { + sizes := []int{4, 8, 16, 32, 64, 256, 320, 1024, 4096, 16384} + for _, size := range sizes { + b.Run(fmt.Sprint("n=", size), func(b *testing.B) { + benchmarkSize(b, size) + }) + } +} |