init

Author: CC11001100

.gitignore

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+.idea

README.md

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+# simple8b的Go实现 
+
+TODO 2022-11-28 02:52:45 测试 
+
+
+

errors.go

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+package simple8b
+
+import "errors"
+
+var ErrFormatNotOk = errors.New("format not ok")

go.mod

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+module github.com/compression-algorithm-research-lab/go-simple8b
+
+go 1.18
+
+require (
+	github.com/compression-algorithm-research-lab/go-varint v0.0.0-20221127141716-08e64be62856 // indirect
+	github.com/compression-algorithm-research-lab/go-zigzag v0.0.0-20221127181654-f3180667f35f // indirect
+	github.com/golang-infrastructure/go-gtypes v0.0.1 // indirect
+)

go.sum

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+github.com/compression-algorithm-research-lab/go-varint v0.0.0-20221127141716-08e64be62856 h1:9JTAw9roxGXImEQFVhmrigg+GzpWK6ASyXuoYnskXgI=
+github.com/compression-algorithm-research-lab/go-varint v0.0.0-20221127141716-08e64be62856/go.mod h1:QzcFfo4K24GHMgyvTF0iQJDFYQG9LiMbRK3dFxCPOP0=
+github.com/compression-algorithm-research-lab/go-zigzag v0.0.0-20221127181654-f3180667f35f h1:tYJkI782TigIodHjv14pxCJwzX75/eFY0V5la+9Dkr4=
+github.com/compression-algorithm-research-lab/go-zigzag v0.0.0-20221127181654-f3180667f35f/go.mod h1:xEIqHDARrh2uoSNToTKjePD67VMdJrLjvBXeydujh3Y=
+github.com/golang-infrastructure/go-gtypes v0.0.1 h1:hnM1OYSwLPLGkZ4C6ecAxgmAUaPTjnhnUtRNmJj4p6c=
+github.com/golang-infrastructure/go-gtypes v0.0.1/go.mod h1:vFMCxFzxdMInvTtgLZRlWI1rS+mui88sMbL5I+zu1hg=

simple8b.go

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+package simple8b
+
+import (
+	"github.com/compression-algorithm-research-lab/go-zigzag"
+	"github.com/golang-infrastructure/go-gtypes"
+)
+
+// CanZipToBits 判断可以压缩到几个bit
+func CanZipToBits[T gtypes.Integer](slice []T) int {
+	var sum T
+	for _, value := range slice {
+		sum |= zigzag.ToZigZag(value)
+	}
+	bitCount := 0
+	for sum > 0 {
+		bitCount++
+		sum >>= 1
+	}
+	return bitCount
+}
+
+// Encode 编码
+func Encode[T gtypes.Integer](slice []T) []byte {
+
+	result := make([]byte, 0)
+
+	// 先计算一下最少可以压缩到几位
+	bits := CanZipToBits(slice)
+	blockSize := (bits + 7) / 8
+	result = append(result, uint8(blockSize))
+
+	// 然后就按照这个来存储了
+	for _, value := range slice {
+		result = append(result, IntToBytes(zigzag.ToZigZag(value), blockSize)...)
+	}
+
+	return result
+}
+
+// DecodeE 解码
+func DecodeE[T gtypes.Integer](bytes []byte) ([]T, error) {
+
+	// 先读取是一个块
+	if len(bytes) == 0 {
+		return nil, ErrFormatNotOk
+	}
+	blockSize := BytesToInt[int]([]byte{bytes[0]})
+	// 进行长度校验，康康块是不是都是合法的
+	if (len(bytes)-1)%blockSize != 0 {
+		return nil, ErrFormatNotOk
+	}
+
+	// 然后就一块一块的读取
+	result := make([]T, 0)
+	count := (len(bytes) - 1) / blockSize
+	for i := 0; i < count; i++ {
+		valueIndex := 1 + i*blockSize
+		valueBytes := bytes[valueIndex : valueIndex+blockSize]
+		result = append(result, zigzag.FromToZigZag(BytesToInt[T](valueBytes)))
+	}
+	return result, nil
+}
+
+// IntToBytes 把给定的整数的低n位转换为字节数组
+func IntToBytes[T gtypes.Integer](value T, blockSize int) []byte {
+	result := make([]byte, blockSize)
+	for index := range result {
+		byteValue := (uint64(0xFF) << index) & uint64(value)
+		result[index] = uint8(byteValue)
+	}
+	return result
+}
+
+// BytesToInt 把字节转为整数
+func BytesToInt[T gtypes.Integer](bytes []byte) T {
+	var r uint64
+	weight := 0
+	for _, x := range bytes {
+		r = r | (uint64(x) << weight)
+		weight += 8
+	}
+	return T(r)
+}

simple8b_test.go

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+package simple8b
+
+import (
+	"testing"
+)
+
+func TestDecodeE(t *testing.T) {
+
+	slice := []int{
+		1, 2, 3, 4, 100, -1, -2, -3, -4,
+	}
+	bytes := Encode(slice)
+	t.Log(bytes)
+
+	decodeSlice, err := DecodeE[int](bytes)
+	t.Log(err)
+	t.Log(decodeSlice)
+
+}