如何从流中读取特定数量的字节? [英] How to read a specific number of bytes from a stream?

问题描述

我有一个带有 BufStream 的结构，其中 T: Read+Write.BufStream 可以是 TcpStream 并且我想从中读取 n 个字节.预定义缓冲区中的字节数不是固定的，但我有一个字符串/流，指示接下来要读取的字节数.

I have a struct with a BufStream<T> where T: Read+Write. The BufStream can be a TcpStream and I'd like to read n bytes from it. Not a fixed amount of bytes in a predefined buffer, but I have a string/stream which indicates the number of bytes to read next.

有什么好的方法可以做到这一点吗?

Is there a nice way to do that?

推荐答案

从 Rust 1.6 开始，Read::read_exact 可用于执行此操作.如果 bytes_to_read 是您需要读取的字节数，可能在运行时确定，而 reader 是要从中读取的流:

Since Rust 1.6, Read::read_exact can be used to do this. If bytes_to_read is the number of bytes you need to read, possibly determined at runtime, and reader is the stream to read from:

let mut buf = vec![0u8; bytes_to_read];
reader.read_exact(&mut buf)?;

read_exact 文档中我不清楚的部分是目标缓冲区可以是动态分配的 Vec.

The part that wasn't clear to me from the read_exact documentation was that the target buffer can be a dynamically-allocated Vec.

感谢 Rust Gitter 社区为我指出这个解决方案.

Thanks to the Rust Gitter community for pointing me to this solution.

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