C++ zip庫對LZ77算法的實現

以下是一個簡單的C++實現LZ77算法的zip庫示例代碼：

#include <iostream>
#include <vector>
#include <string>
#include <algorithm>

using namespace std;

class LZ77 {
public:
    vector<pair<int, int>> compress(const string& input, int windowSize, int bufferSize) {
        vector<pair<int, int>> compressedData;
        int pos = 0;

        while (pos < input.length()) {
            int windowStart = max(0, pos - windowSize);
            int windowEnd = pos - 1;
            int bestMatchPos = -1;
            int bestMatchLen = 0;

            for (int i = windowStart; i < windowEnd; i++) {
                int len = 0;
                while (input[pos + len] == input[i + len] && len < bufferSize) {
                    len++;
                }

                if (len > bestMatchLen) {
                    bestMatchPos = i;
                    bestMatchLen = len;
                }
            }

            if (bestMatchLen > 0) {
                compressedData.push_back({pos - bestMatchPos, bestMatchLen});
                pos += bestMatchLen;
            } else {
                compressedData.push_back({0, input[pos]});
                pos++;
            }
        }

        return compressedData;
    }

    string decompress(const vector<pair<int, int>>& compressedData) {
        string decompressedData;
        
        for (auto& entry : compressedData) {
            if (entry.first == 0) {
                decompressedData += entry.second;
            } else {
                int pos = decompressedData.length() - entry.first;
                for (int i = 0; i < entry.second; i++) {
                    decompressedData += decompressedData[pos + i];
                }
            }
        }

        return decompressedData;
    }
};

int main() {
    LZ77 lz77;

    string input = "abracadabra";
    int windowSize = 4;
    int bufferSize = 4;

    vector<pair<int, int>> compressedData = lz77.compress(input, windowSize, bufferSize);
    string decompressedData = lz77.decompress(compressedData);

    cout << "Original data: " << input << endl;
    cout << "Compressed data: ";
    for (auto& entry : compressedData) {
        cout << "(" << entry.first << ", " << entry.second << ") ";
    }
    cout << endl;
    cout << "Decompressed data: " << decompressedData << endl;

    return 0;
}

在上面的示例中，我們定義了一個LZ77類，其中包含了壓縮和解壓縮函數。在壓縮函數中，我們首先定義了窗口大小和緩沖區大小，然后遍歷輸入字符串，找到最佳匹配位置和長度。最后，將匹配位置和長度或者字面值字符存入壓縮數據中。在解壓縮函數中，我們根據壓縮數據重新構建原始數據。在主函數中，我們使用示例輸入數據調用壓縮和解壓縮函數，并輸出壓縮和解壓縮的結果。