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|
package sortedset
import (
"bytes"
"fmt"
"math/rand"
"testing"
)
var intersectSpecializationSizes = []int{16}
func TestIntersect(t *testing.T) {
for _, test := range []struct {
name string
a []byte
b []byte
size int
expect []byte
}{
{
name: "empty",
size: 1,
},
{
name: "size 1, empty a",
a: nil,
b: []byte{1, 2, 3, 4, 5},
size: 1,
expect: nil,
},
{
name: "size 1, empty b",
a: []byte{1, 2, 3, 4, 5},
b: nil,
size: 1,
expect: nil,
},
{
name: "size 1, a == b",
a: []byte{1, 2, 3, 4, 5},
b: []byte{1, 2, 3, 4, 5},
size: 1,
expect: []byte{1, 2, 3, 4, 5},
},
{
name: "size 1, a < b",
a: []byte{1, 2, 3},
b: []byte{4, 5, 6},
size: 1,
expect: nil,
},
{
name: "size 1, b < a",
a: []byte{4, 5, 6},
b: []byte{1, 2, 3},
size: 1,
expect: nil,
},
{
name: "size 1, a <= b",
a: []byte{1, 2, 3},
b: []byte{3, 4, 5},
size: 1,
expect: []byte{3},
},
{
name: "size 1, b <= a",
a: []byte{3, 4, 5},
b: []byte{1, 2, 3},
size: 1,
expect: []byte{3},
},
{
name: "size 1, interleaved 1",
a: []byte{1, 3, 5},
b: []byte{2, 4, 6},
size: 1,
expect: nil,
},
{
name: "size 1, interleaved 2",
a: []byte{2, 4, 6},
b: []byte{1, 3, 5},
size: 1,
expect: nil,
},
{
name: "size 1, overlapping 1",
a: []byte{1, 2, 3, 4, 5, 6},
b: []byte{2, 4, 6, 8},
size: 1,
expect: []byte{2, 4, 6},
},
{
name: "size 1, overlapping 2",
a: []byte{2, 3, 4, 5},
b: []byte{1, 3, 5, 7},
size: 1,
expect: []byte{3, 5},
},
} {
t.Run(test.name, func(t *testing.T) {
buf := make([]byte, len(test.a)+len(test.b))
actual := Intersect(buf, test.a, test.b, test.size)
assertArraysEqual(t, test.expect, actual, test.size)
})
}
// Test the specializations.
for _, size := range intersectSpecializationSizes {
t.Run(fmt.Sprintf("size %d, random", size), func(t *testing.T) {
const maxCount = 100
const iterations = 1000
prng := rand.New(rand.NewSource(0))
buf := make([]byte, size*maxCount*2)
for i := 0; i < iterations; i++ {
count := prng.Intn(maxCount)
for _, p := range overlapChances {
setA, setB := randomSortedSetPair(prng, size, count, p)
actual := Intersect(buf[:0], setA, setB, size)
// Manual intersection on a sorted array:
combined := combineArrays(setA, setB, size)
expected := buf[:0]
if len(combined) > 0 {
prev := combined[:size]
for i := size; i < len(combined); i += size {
item := combined[i : i+size]
if bytes.Equal(item, prev) {
expected = append(expected, item...)
}
prev = item
}
}
assertArraysEqual(t, expected, actual, size)
}
}
})
}
}
func BenchmarkIntersect(b *testing.B) {
for _, size := range intersectSpecializationSizes {
for _, p := range overlapChances {
b.Run(fmt.Sprintf("size %d, with %d%% chance of overlap", size, int(p*100)), func(b *testing.B) {
const bytes = 64 * 1024
prng := rand.New(rand.NewSource(0))
setA, setB := randomSortedSetPair(prng, size, bytes/size, p)
buf := make([]byte, bytes*2)
b.SetBytes(int64(bytes * 2))
b.ResetTimer()
for i := 0; i < b.N; i++ {
Intersect(buf[:0], setA, setB, size)
}
})
}
}
b.Run("no overlap", func(b *testing.B) {
prng := rand.New(rand.NewSource(0))
array, _ := randomSortedArray(prng, 16, 128, 0.0)
dst := make([]byte, 16*64)
b.ResetTimer()
for i := 0; i < b.N; i++ {
Intersect(dst, array[:64*16], array[64*16:], 16)
}
})
b.Run("empty", func(b *testing.B) {
for i := 0; i < b.N; i++ {
Intersect(nil, nil, nil, 16)
}
})
}
|
