LZW算法 golang实现

淩亂°似流年 2022-06-07 07:18 181阅读 0赞

// LZW Data Compression in Golang
    package main
    import "fmt"
    
    
    func compressLZW(testStr string) []int {    
        code := 256
        dictionary := make(map[string]int)
        for i := 0; i < 256; i++ {
            dictionary[string(i)] = i
        }
    
        currChar := ""
        result := make([]int, 0)    
        for _, c := range []byte(testStr) { 
            phrase := currChar + string(c)
            if _, isTrue := dictionary[phrase]; isTrue {        
                currChar = phrase
            } else {
                result = append(result, dictionary[currChar])
                dictionary[phrase] = code
                code++
                currChar = string(c)
            }
        }
        if currChar != "" {
            result = append(result, dictionary[currChar])
        }
        return result
    }
    
    
    func decompressLZW(compressed []int) string {    
        code := 256
        dictionary := make(map[int]string)
        for i := 0; i < 256; i++ {
            dictionary[i] = string(i)
        }
    
        currChar := string(compressed[0])
        result := currChar
        for _, element := range compressed[1:] {
            var word string
            if x, ok := dictionary[element]; ok {
                word = x
            } else if element == code {
                word = currChar + currChar[:1]
            } else {
                panic(fmt.Sprintf("Bad compressed element: %d", element))
            }
    
            result += word
    
            dictionary[code] = currChar + word[:1]
            code++
    
            currChar = word
        }
        return result
    }
    
    func main() {
        fmt.Print("Enter any string :")
        var testStr string
        fmt.Scanln(&testStr)
    
        compressed := compressLZW(testStr)
        fmt.Println("\nAfter Compression :", compressed)
    
        uncompression := decompressLZW(compressed)
        fmt.Println("\nAfter Uncompression :", uncompression)
    }

参考  
[http://www.golangprograms.com/golang-program-for-implementation-lzw-data-compression-and-uncompression.html][http_www.golangprograms.com_golang-program-for-implementation-lzw-data-compression-and-uncompression.html]

[http_www.golangprograms.com_golang-program-for-implementation-lzw-data-compression-and-uncompression.html]: http://www.golangprograms.com/golang-program-for-implementation-lzw-data-compression-and-uncompression.html