将 InputStream 读入 Data 对象 [英] Reading an InputStream into a Data object

问题描述

在 Swift 3.x 中，我们通常使用 Data 处理二进制数据；从中你可以生成大多数其他重要的类型，并且上面有一些有用的函数.

In Swift 3.x, we usually handle binary data using Data; from it you can generate most other important types, and there are useful functions on it.

但是我如何从 InputStream 创建一个 Data ?有什么好的办法吗?

But how do I create a Data from an InputStream? Is there a nice way?

推荐答案

我找不到好的方法.我们可以为不安全的东西创建一个漂亮的包装器:

I could not find a nice way. We can create a nice-ish wrapper around the unsafe stuff:

extension Data {
    init(reading input: InputStream) throws {
        self.init()
        input.open()
        defer {
            input.close()
        }

        let bufferSize = 1024
        let buffer = UnsafeMutablePointer<UInt8>.allocate(capacity: bufferSize)
        defer {
            buffer.deallocate()
        }
        while input.hasBytesAvailable {
            let read = input.read(buffer, maxLength: bufferSize)
            if read < 0 {
                //Stream error occured
                throw input.streamError!
            } else if read == 0 {
                //EOF
                break
            }
            self.append(buffer, count: read)
        }
    }
}

这是针对 Swift 5 的.查找带有测试的完整代码(以及仅读取部分流的变体)这里.

This is for Swift 5. Find full code with test (and a variant that reads only some of the stream) here.

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