逐行读取文件(不是 utf-8)? [英] read file(not utf-8) line by line?

问题描述

是否可以逐行读取文件，如果它不是使用 std::io::File 和 std::io::BufReader?

Is it possible to read file line by line, if it is not in utf-8 encoding with std::io::File and std::io::BufReader?

我查看 std::io::Lines 并返回 Result，所以我担心，我是否实现了自己的 BufReader 来做同样的事情，但返回 Vec，或者我可以重用 std::io::BufReader 以某种方式?

I look at std::io::Lines and it return Result<String>, so I worry, have I implement my own BufReader that do the same, but return Vec<u8> instead, or I can reuse std::io::BufReader in some way?

推荐答案

您不必重新实现 BufReader 本身，它为您的用例提供了所需的方法 read_until:

You do not have to re-implement BufReader itself, it provides exactly the method you need for your usecase read_until:

fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize>

您提供自己的Vec，文件的内容将被附加，直到遇到byte(0x0A 为LF).

You supply your own Vec<u8> and the content of the file will be appended until byte is encountered (0x0A being LF).

有几个潜在的问题:

• 缓冲区不仅可以以 LF 字节结束，还可以以 CR LF 序列结束，
• 在后续调用之间清除 buf 由您决定.

• the buffer may end not only with a LF byte, but with a CR LF sequence,
• it is up to you to clear buf between subsequent calls.

一个简单的while let Ok(_) = reader.read_until(0x0A as u8, buffer) 应该让你很容易阅读你的文件.

A simple while let Ok(_) = reader.read_until(0x0A as u8, buffer) should let you read your file easily enough.

你可以考虑实现一个 std::io::Lines 等价物，它从编码转换为 UTF-8 以提供一个很好的 API，尽管它会降低性能.

You may consider implement a std::io::Lines equivalent which converts from the encoding to UTF-8 to provide a nice API, though it will have a performance cost.

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