我正在尝试读取 TCP 套接字连接中的长字符串。
对于读取短长度字符串,它工作正常。但是当我试图发送长长度的 base64 编码图像时。它正在崩溃,我试图增加到 maxReadLength = 10000
,但它仍然无法正常工作。
阅读收到的消息
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
最佳答案
问题是缓冲区只分配一次,但每次都释放 什么时候
String(bytesNoCopy: buffer, length: numberOfBytesRead, encoding: .ascii, freeWhenDone: true)
被调用。这是一个演示问题的简短的独立示例:
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
是解决问题的一种选择,但请注意
你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,这是自动的
函数返回时释放。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) {
// ...
}
}
关于swift - 未分配正在释放的指针 [Swift],我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/52708579/