matlab实现压缩算法代码

由于压缩算法种类繁多，这里提供一个简单的Lempel-Ziv（LZ77）压缩算法的MATLAB代码示例：

% LZ77压缩算法实现

function [compressedData, dictionary] = lz77Compress(inputData, windowSize, lookAheadSize)

% 初始化字典
dictionary = {};

% 初始化窗口和向前视野
windowStart = 1;
windowEnd = windowSize;
lookAheadStart = 1;
lookAheadEnd = lookAheadSize;

% 初始化输出
compressedData = [];

% 迭代压缩
while lookAheadEnd <= length(inputData)

% 在字典中查找匹配
matchLength = 0;
matchIndex = 0;
for i = length(dictionary):-1:1
if lookAheadStart > dictionary{i}.position || ...
lookAheadStart + matchLength > length(inputData)
continue;
end
currentMatchLength = 0;
while inputData(lookAheadStart + currentMatchLength) == ...
inputData(dictionary{i}.position + currentMatchLength)
currentMatchLength = currentMatchLength + 1;
if lookAheadStart + currentMatchLength > length(inputData)
break;
end
end
if currentMatchLength > matchLength
matchLength = currentMatchLength;
matchIndex = i;
end
end

% 将匹配/未匹配的符号添加到输出中
if matchLength > 0
compressedData = [compressedData, matchIndex-1, matchLength];
else
compressedData = [compressedData, 0, inputData(lookAheadStart)];
end

% 将新匹配添加到字典中
if matchLength > 0
dictionary{end+1} = struct('position', lookAheadStart, 'length', matchLength);
end

% 更新窗口和向前视野
windowStart = windowStart + matchLength;
windowEnd = windowEnd + matchLength;
lookAheadStart = lookAheadStart + matchLength + 1;
lookAheadEnd = lookAheadEnd + matchLength + 1;

% 截取窗口和向前视野
windowStart = max(windowStart, 1);
windowEnd = min(windowEnd, length(inputData));
lookAheadStart = max(lookAheadStart, 1);
lookAheadEnd = min(lookAheadEnd, length(inputData));

% 限制字典大小
if length(dictionary) > windowSize
dictionary = dictionary(2:end);
end

end

end

使用示例：

% 原始数据
inputData = 'ABBABBABBAABBAB';

% 压缩
[compressedData, dictionary] = lz77Compress(inputData, 5, 6);

% 输出压缩结果和字典
disp(compressedData);
disp(dictionary);

% 解压
decompressedData = lz77Decompress(compressedData, dictionary);

% 检查是否正确解压
assert(strcmp(decompressedData, inputData));

其中，lz77Decompress()函数是一个实现LZ77解压缩的函数，可以自行编写。