lzw matlab

LZW (Lempel-Ziv-Welch) 是一种常用的无损压缩算法，用于减小数据的存储空间。在 MATLAB 中，可以使用以下代码实现 LZW 压缩和解压缩：

function compressed_data = lzw_compress(data)
    dict = cell(256, 1);
    for i = 1:256
        dict{i} = char(i-1);
    end
    
    compressed_data = [];
    idx = 257;
    current_code = data(1);
    
    for i = 2:length(data)
        next_code = [current_code, data(i)];
        if ismember(next_code, dict)
            current_code = next_code;
        else
            compressed_data = [compressed_data, find(strcmp(dict, current_code))-1];
            dict{idx} = next_code;
            idx = idx + 1;
            current_code = data(i);
        end
    end
    
    compressed_data = [compressed_data, find(strcmp(dict, current_code))-1];
end

function decompressed_data = lzw_decompress(compressed_data)
    dict = cell(256, 1);
    for i = 1:256
        dict{i} = char(i-1);
    end
    
    decompressed_data = dict{compressed_data(1)+1};
    idx = 257;
    
    for i = 2:length(compressed_data)
        if compressed_data(i) >= idx
            entry = [dict{compressed_data(i-1)+1}, dict{compressed_data(i-1)+1}(1)];
        else
            entry = dict{compressed_data(i)+1};
        end
        
        decompressed_data = [decompressed_data, entry];
        
        dict{idx} = [dict{compressed_data(i-1)+1}, entry(1)];
        idx = idx + 1;
    end
end

你可以将要压缩的数据作为输入传递给 `lzw_compress` 函数，它将返回压缩后的数据。同样地，你可以将压缩数据传递给 `lzw_decompress` 函数，它将返回解压缩后的数据。请注意，这个实现仅适用于 ASCII 字符。