lz77压缩算法c语言实现

以下是一个简单的 C 语言实现 LZ77 压缩算法的示例代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define BUFFER_SIZE 256
#define LOOKAHEAD_SIZE 16
#define MAX_DISTANCE 4095

typedef struct {
    int distance;
    int length;
    char next;
} Match;

int findMatch(char *buffer, int position, int bufferSize) {
    int maxLength = 0;
    int matchPosition = 0;
    for (int i = position - MAX_DISTANCE; i < position; i++) {
        int j = 0;
        while (buffer[i + j] == buffer[position + j] && j < LOOKAHEAD_SIZE) {
            j++;
        }
        if (j > maxLength) {
            maxLength = j;
            matchPosition = i;
        }
    }
    Match match = {position - matchPosition, maxLength, buffer[position + maxLength]};
    printf("<%d,%d,%c>", match.distance, match.length, match.next);
    return maxLength;
}

void compress(char *source) {
    int position = 0;
    int bufferSize = strlen(source);
    while (position < bufferSize) {
        int length = findMatch(source, position, bufferSize);
        if (length == 0) {
            printf("%c", source[position]);
            position++;
        } else {
            position += length;
        }
    }
}

int main() {
    char source[BUFFER_SIZE];
    printf("Enter the source string: ");
    fgets(source, BUFFER_SIZE, stdin);
    printf("Compressed data: ");
    compress(source);
    printf("\n");
    return 0;
}

该实现基于滑动窗口和查找窗口中最长匹配的原理。算法每次读取输入数据中的一个字符，并在滑动窗口中查找最长的匹配。如果找到了匹配，就输出匹配的距离、长度和下一个字符；否则，就输出当前字符。