以UTF-8字符串存储二进制数据 [英] Storing binary data in UTF-8 string

问题描述

我想使用WebSocket传输二进制数据，但您只能使用WebSockets传输UTF-8字符串。

I want to use a WebSocket to transfer binary data, but you can only use WebSockets to transfer UTF-8 strings.

使用base64对其进行编码是一种选择，但我的理解是，当您的文本可能从一种格式转换为另一种格式时，最理想的是base64。在这种情况下，我知道数据将始终是UTF-8，那么有没有更好的方法来编码UTF-8字符串中的二进制数据而不支付base64的33％大小溢价？

Encoding it using base64 is one option, but my understanding is that base64 is most desirable when your text might be converted from one format to another. In this case, I know the data will always be UTF-8, so is there a better way of encoding binary data in a UTF-8 string without paying base64's 33% size premium?

这个问题主要是学术性的，因为二进制支持最终可能会被添加到WebSocket中，而base64在此期间是一个完美的替代方案。

This question is mostly academic, as binary support will probably be added to WebSocket eventually, and base64 is a perfectly cromulent alternative in the meantime.

推荐答案

您可以使用Base-128编码而不是Base-64编码。这只会导致1/3与1/3相反的开销。

You could use a Base-128 encoding instead of a Base-64 encoding. That will only result in an overhead of 1/7 in opposite to 1/3.

这个想法是使用所有可以用单个字节表示的Unicode代码点在UTF-8（0-127）。这意味着所有字节都以 0 开头，因此数据还剩7位：

The idea is to use all Unicode code points that can be represented in a single byte in UTF-8 (0–127). That means all bytes begin with a 0 so there are seven bits left for the data:

0‍xxxxxxx

这导致编码，其中7个输入字节使用8个输出字节进行编码：

That results in an encoding where 7 input bytes are encoded using 8 output bytes:

input:  aaaaaaaa bbbbbbbb cccccccc dddddddd eeeeeeee ffffffff gggggggg
output: 0aaaaaaa 0abbbbbb 0bbccccc 0cccdddd 0ddddeee 0eeeeeff 0ffffffg 0ggggggg

因此输出与输入比率为8/7。

So the output to input ratio is 8/7.

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