bitmap commit

bitmap/README.md

@@ -0,0 +1,12 @@
+# Owner
+lh1814
+
+# Author 
+lh1814
+
+# Reviewer
+
+
+# Description
+    算法和数据结构应用小工具
+    bitmap ---------------> lh1814

bitmap/bitmap.go

@@ -0,0 +1,192 @@
+package bitmap
+
+import (
+	"encoding/base64"
+	"sync"
+)
+
+/*
+@Author: by LH
+@date:  2019-06-12
+@function:位图算法go语言版本类型抽象
+*/
+const byteBitLength = 8 //一个字节的位数，也是一个uint8类型的位数
+
+type BitMap struct {
+	value []uint8
+	//bit   uint64
+	mu    sync.RWMutex
+	count uint64
+}
+
+func NewBitMapFromBase64String(s string) (*BitMap, error) { //不要太长比较好
+	decodeBytes, e := base64.StdEncoding.DecodeString(s)
+	if e != nil {
+		return nil, e
+	}
+
+	return &BitMap{
+		value: decodeBytes,
+		count: count(decodeBytes),
+		mu:    sync.RWMutex{},
+	}, nil
+}
+
+//统计1数量
+func count(m []byte) (r uint64) {
+	for _, v := range m {
+		for i := 0; i < byteBitLength; i++ {
+			if ByteIndexIsOne(v, i) {
+				r++
+			}
+		}
+	}
+	return
+}
+
+//从string加载
+func NewBitMapFromString(s string) *BitMap {
+
+	return &BitMap{
+		value: []byte(s),
+		mu:    sync.RWMutex{},
+		count: count([]byte(s)),
+	}
+}
+
+func (b *BitMap) Reset() {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	b.value = make([]uint8, 0)
+	b.count = 0
+}
+
+func (b *BitMap) Count() uint64 {
+	return b.count
+}
+
+//获取当前位数长度
+func (b *BitMap) Length() int {
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+	return len(b.value) * byteBitLength
+}
+
+//func (b *BitMap) BitLength() uint64 {
+//	return b.bit
+//}
+
+//判断指定位置是否为1
+func (b *BitMap) IsBit(index int) (r bool) {
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+	if index < 0 || index >= len(b.value)*byteBitLength { //边界情况
+		return
+	}
+	x := index / byteBitLength
+	y := index % byteBitLength
+	if ByteIndexIsOne(b.value[x], y) {
+		r = true
+	}
+	return
+}
+
+//value数组增加num个长度
+func (b *BitMap) addLength(n int) {
+	for i := 0; i < n; i++ {
+		b.value = append(b.value, 0)
+	}
+}
+
+//设置指定位置为1
+func (b *BitMap) SetBit(index int) {
+	if index < 0 {
+		return
+	}
+
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	if index >= len(b.value)*byteBitLength { //需要加长度
+		b.addLength(index/byteBitLength + 1 - len(b.value))
+	}
+
+	arrIndex := index / byteBitLength
+	bitIndex := index % byteBitLength
+
+	if !ByteIndexIsOne(b.value[arrIndex], bitIndex) { //不为1时设置为1
+		b.value[arrIndex] ^= 128 >> bitIndex
+		b.count++
+	}
+
+}
+
+//设置指定位置为0
+func (b *BitMap) CancelBit(index int) {
+	if index < 0 || index >= len(b.value)*byteBitLength {
+		return
+	}
+
+	arrIndex := index / byteBitLength
+	bitIndex := index % byteBitLength
+
+	if ByteIndexIsOne(b.value[arrIndex], bitIndex) { //为1时设置为0
+		b.mu.Lock()
+		defer b.mu.Unlock()
+		b.value[arrIndex] ^= 128 >> bitIndex
+		b.count--
+	}
+}
+
+//base64转化为string
+func (b *BitMap) Base64String() string {
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+	return base64.StdEncoding.EncodeToString(b.value)
+}
+
+//转 string
+func (b *BitMap) String() string {
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+	return string(b.value)
+}
+
+//判断一个byte的指定位置是否为1,顺序为从高位到低位下标分别为0->7
+func ByteIndexIsOne(a byte, index int) bool {
+	if index < 0 || index >= byteBitLength {
+		return false
+	}
+
+	//t := a
+	//t ^= 128 >> index //判断t是否和a相等
+	a <<= index
+	a >>= 7
+	if a == 0 {
+		return false
+	}
+	return true
+}
+
+func ByteReverse(b byte) byte {
+	for i := 0; i < 4; i++ {
+		if (b&(128>>i))>>(7-i) != (b&(1<<i))>>i {
+			b ^= 128 >> i
+			b ^= 1 << i
+		}
+	}
+	return b
+}
+
+//>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>以下函数为测试，封装好类型的在上面<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
+//从第0位开始判断
+func GetBit(s []uint8, index int) (r bool) {
+	if index < 0 || index >= len(s)*byteBitLength { //边界情况
+		return
+	}
+	a := index / byteBitLength
+	b := index % byteBitLength
+	if ByteIndexIsOne(s[a], b) {
+		r = true
+	}
+	return
+}

bitmap/bitmap_test.go

@@ -0,0 +1,41 @@
+package bitmap
+
+import (
+	"testing"
+)
+
+/*
+@Author: by LH
+@date:  2020/7/21
+@function:
+*/
+
+func TestBitMap(t *testing.T) {
+	var b BitMap
+
+	b.SetBit(1)
+	b.SetBit(3)
+	b.SetBit(5)
+
+	if !b.IsBit(1) || !b.IsBit(3) || !b.IsBit(5) {
+		t.Fatal("b 1 3 5 should be true")
+	}
+
+	if b.Count() != 3 {
+		t.Fatal("b length should be 3")
+	}
+
+	b.Base64String()
+	c, e := NewBitMapFromBase64String(b.Base64String())
+	if e != nil {
+		t.Fatal(e)
+	}
+	if !c.IsBit(1) || !c.IsBit(3) || !c.IsBit(5) {
+		t.Fatal("c 1 3 5 should be true")
+	}
+
+	if c.Count() != 3 {
+		t.Fatal("c length should be 3")
+	}
+
+}

go.mod

@@ -0,0 +1,3 @@
+module library
+
+go 1.13