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// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package bitutils_test
import (
"math/bits"
"testing"
"unsafe"
"github.com/apache/arrow-go/v18/arrow/bitutil"
"github.com/apache/arrow-go/v18/arrow/endian"
"github.com/apache/arrow-go/v18/internal/bitutils"
"github.com/stretchr/testify/assert"
)
var toLittleEndian func(uint64) uint64
func init() {
if endian.IsBigEndian {
toLittleEndian = bits.ReverseBytes64
} else {
toLittleEndian = func(in uint64) uint64 { return in }
}
}
func TestBitRunReaderZeroLength(t *testing.T) {
reader := bitutils.NewBitRunReader(nil, 0, 0)
assert.Zero(t, reader.NextRun().Len)
}
func bitmapFromSlice(vals []int, bitOffset int64) []byte {
out := make([]byte, int(bitutil.BytesForBits(int64(len(vals))+bitOffset)))
writer := bitutil.NewBitmapWriter(out, int(bitOffset), len(vals))
for _, val := range vals {
if val == 1 {
writer.Set()
} else {
writer.Clear()
}
writer.Next()
}
writer.Finish()
return out
}
func TestBitRunReader(t *testing.T) {
tests := []struct {
name string
val []int
bmvec []int
offset int64
len int64
expected []bitutils.BitRun
}{
{"normal operation",
[]int{5, 0, 7, 1, 3, 0, 25, 1, 21, 0, 26, 1, 130, 0, 65, 1},
[]int{1, 0, 1},
0, -1,
[]bitutils.BitRun{
{1, true},
{1, false},
{1, true},
{5, false},
{7, true},
{3, false},
{25, true},
{21, false},
{26, true},
{130, false},
{65, true},
},
},
{"truncated at word", []int{7, 1, 58, 0}, []int{}, 1, 63,
[]bitutils.BitRun{{6, true}, {57, false}},
},
{"truncated within word multiple of 8 bits",
[]int{7, 1, 5, 0}, []int{}, 1, 7,
[]bitutils.BitRun{{6, true}, {1, false}},
},
{"truncated within word", []int{37 + 40, 0, 23, 1}, []int{}, 37, 53,
[]bitutils.BitRun{{40, false}, {13, true}},
},
{"truncated multiple words", []int{5, 0, 30, 1, 95, 0}, []int{1, 0, 1},
5, (3 + 5 + 30 + 95) - (5 + 3), []bitutils.BitRun{{3, false}, {30, true}, {92, false}},
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
bmvec := tt.bmvec
for i := 0; i < len(tt.val); i += 2 {
for j := 0; j < tt.val[i]; j++ {
bmvec = append(bmvec, tt.val[i+1])
}
}
bitmap := bitmapFromSlice(bmvec, 0)
length := int64(len(bmvec)) - tt.offset
if tt.len != -1 {
length = tt.len
}
reader := bitutils.NewBitRunReader(bitmap, tt.offset, length)
results := make([]bitutils.BitRun, 0)
for {
results = append(results, reader.NextRun())
if results[len(results)-1].Len == 0 {
break
}
}
assert.Zero(t, results[len(results)-1].Len)
results = results[:len(results)-1]
assert.Equal(t, tt.expected, results)
})
}
}
func TestBitRunReaderAllFirstByteCombos(t *testing.T) {
for offset := int64(0); offset < 8; offset++ {
for x := int64(0); x < (1<<8)-1; x++ {
bits := int64(toLittleEndian(uint64(x)))
reader := bitutils.NewBitRunReader((*(*[8]byte)(unsafe.Pointer(&bits)))[:], offset, 8-offset)
results := make([]bitutils.BitRun, 0)
for {
results = append(results, reader.NextRun())
if results[len(results)-1].Len == 0 {
break
}
}
assert.Zero(t, results[len(results)-1].Len)
results = results[:len(results)-1]
var sum int64
for _, r := range results {
sum += r.Len
}
assert.EqualValues(t, sum, 8-offset)
}
}
}
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