未分配要释放的指针[Swift]
未分配要释放的指针[Swift]
提问于 2018-10-09 03:04:19
我正在尝试读取TCP套接字连接中的长字符串。对于读取短长度的字符串，它工作得很好。但当我试图发送长长的base64编码的图像。它正在崩溃，我试图增加到maxReadLength = 10000，但它仍然不工作。
读取传入消息的
private func readAvailableBytes(stream: InputStream) {
let buffer = UnsafeMutablePointer<UInt8>.allocate(capacity: maxReadLength)
while stream.hasBytesAvailable {
let numberOfBytesRead = inputStream.read(buffer, maxLength: maxReadLength)
if numberOfBytesRead < 0 {
if let _ = inputStream.streamError {
break
}
}
❌ Crashing in below line ❌
if let reciviedMsg = String(bytesNoCopy: buffer,
length: numberOfBytesRead,
encoding: .ascii,
freeWhenDone: true)
{
delegate?.scoktDidRecivceNewMessagew(message: reciviedMsg)
}
}
}错误
malloc: *** error for object 0x101890c00: pointer being freed was not allocated
*** set a breakpoint in malloc_error_break to debug回答 1
Stack Overflow用户
回答已采纳
发布于 2018-10-09 03:37:20
问题是，缓冲区只分配一次，但每次都会释放
String(bytesNoCopy: buffer, length: numberOfBytesRead, encoding: .ascii, freeWhenDone: true)是调用的。下面是一个简短的、自包含的示例，演示了这个问题：
let buffer = UnsafeMutablePointer<UInt8>.allocate(capacity: 4)
memcpy(buffer, "abcd", 4)
var s = String(bytesNoCopy: buffer, length: 4, encoding: .ascii, freeWhenDone: true)
// OK
s = String(bytesNoCopy: buffer, length: 4, encoding: .ascii, freeWhenDone: true)
// malloc: *** error for object 0x101d8dc40: pointer being freed was not allocated使用freeWhenDone: false是解决该问题的一种选择，但请注意，您最终必须释放缓冲区。
另一种方法是使用Array (或Data)作为缓冲区，该缓冲区在函数返回时自动释放。示例：
var buffer = [UInt8](repeating: 0, count: maxReadLength)
while inputStream.hasBytesAvailable {
let numberOfBytesRead = inputStream.read(&buffer, maxLength: maxReadLength)
if numberOfBytesRead < 0 {
break
}
if let receivedMsg = String(bytes: buffer[..<numberOfBytesRead], encoding: .ascii) {
// ...
}
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/52708579
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