用matlab写一个64解码器代码
时间: 2024-04-09 18:30:06 浏览: 25
抱歉,我给出的前一个答案有误。以下是使用 MATLAB 编写的 Base64 解码器代码:
```matlab
function decodedStr = base64decode(encodedStr)
% 构建 Base64 字符映射表
Base64Chars = ['A':'Z', 'a':'z', '0':'9', '+', '/'];
Base64Values = [0:25 26:51 52:61 62 63];
Base64Map = containers.Map(Base64Chars, Base64Values);
% 删除编码字符串中的非 Base64 字符
encodedStr = regexprep(encodedStr, '[^A-Za-z0-9+/]', '');
% 解码
numChars = length(encodedStr);
numGroups = floor(numChars / 4);
decodedStr = blanks(numGroups * 3);
for i = 0:numGroups-1
groupStartIndex = i*4 + 1;
groupEndIndex = groupStartIndex + 3;
groupChars = encodedStr(groupStartIndex:groupEndIndex);
groupValues = zeros(1, 4);
for j = 1:4
groupValues(j) = Base64Map(groupChars(j));
end
decodedValues = base64decodeGroup(groupValues);
for j = 1:3
decodedStr(i*3 + j) = char(decodedValues(j));
end
end
end
function decodedValues = base64decodeGroup(groupValues)
decodedValues = zeros(1, 3);
decodedValues(1) = bitshift(groupValues(1), 2) + bitshift(groupValues(2), -4);
decodedValues(2) = bitshift(groupValues(2), 4) + bitshift(groupValues(3), -2);
decodedValues(3) = bitshift(groupValues(3), 6) + groupValues(4);
end
```
使用示例:
```matlab
encodedStr = 'aHR0cHM6Ly9keS54Zmx0ZC5jYy9hcGkvdjEvY2xpZW50L3N1YnNjcmliZT90b2tlbj1iZTE0YTNhNWRkZDZlMDUwN2JjNWIwZjkwZTllZjgwYQ==';
decodedStr = base64decode(encodedStr);
disp(decodedStr);
```
请将 `encodedStr` 替换为您想要解码的 Base64 字符串。运行代码后,将会输出解码后的字符串。