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Avoid doing unaligned reads/writes via UnsafePointer #146

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merged 1 commit into from
Dec 12, 2015
Merged

Avoid doing unaligned reads/writes via UnsafePointer #146

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46 changes: 34 additions & 12 deletions WebSocket.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -434,6 +434,33 @@ public class WebSocket : NSObject, NSStreamDelegate {
return false
}

///read a 16 bit big endian value from a buffer
private static func readUint16(buffer: UnsafePointer<UInt8>, offset: Int) -> UInt16 {
return (UInt16(buffer[offset + 0]) << 8) | UInt16(buffer[offset + 1])
}

///read a 64 bit big endian value from a buffer
private static func readUint64(buffer: UnsafePointer<UInt8>, offset: Int) -> UInt64 {
var value = UInt64(0)
for i in 0...7 {
value = (value << 8) | UInt64(buffer[offset + i])
}
return value
}

///write a 16 bit big endian value to a buffer
private static func writeUint16(buffer: UnsafeMutablePointer<UInt8>, offset: Int, value: UInt16) {
buffer[offset + 0] = UInt8(value >> 8)
buffer[offset + 1] = UInt8(value & 0xff)
}

///write a 64 bit big endian value to a buffer
private static func writeUint64(buffer: UnsafeMutablePointer<UInt8>, offset: Int, value: UInt64) {
for i in 0...7 {
buffer[offset + i] = UInt8((value >> (8*UInt64(7 - i))) & 0xff)
}
}

///process the websocket data
private func processRawMessage(buffer: UnsafePointer<UInt8>, bufferLen: Int) {
let response = readStack.last
Expand Down Expand Up @@ -487,8 +514,7 @@ public class WebSocket : NSObject, NSStreamDelegate {
if payloadLen == 1 {
code = CloseCode.ProtocolError.rawValue
} else if payloadLen > 1 {
let codeBuffer = UnsafePointer<UInt16>((buffer+offset))
code = codeBuffer[0].bigEndian
code = WebSocket.readUint16(buffer, offset: offset)
if code < 1000 || (code > 1003 && code < 1007) || (code > 1011 && code < 3000) {
code = CloseCode.ProtocolError.rawValue
}
Expand All @@ -514,12 +540,10 @@ public class WebSocket : NSObject, NSStreamDelegate {
}
var dataLength = UInt64(payloadLen)
if dataLength == 127 {
let bytes = UnsafePointer<UInt64>((buffer+offset))
dataLength = bytes[0].bigEndian
dataLength = WebSocket.readUint64(buffer, offset: offset)
offset += sizeof(UInt64)
} else if dataLength == 126 {
let bytes = UnsafePointer<UInt16>((buffer+offset))
dataLength = UInt64(bytes[0].bigEndian)
dataLength = UInt64(WebSocket.readUint16(buffer, offset: offset))
offset += sizeof(UInt16)
}
if bufferLen < offset || UInt64(bufferLen - offset) < dataLength {
Expand Down Expand Up @@ -657,8 +681,8 @@ public class WebSocket : NSObject, NSStreamDelegate {
///write a an error to the socket
private func writeError(code: UInt16) {
let buf = NSMutableData(capacity: sizeof(UInt16))
let buffer = UnsafeMutablePointer<UInt16>(buf!.bytes)
buffer[0] = code.bigEndian
let buffer = UnsafeMutablePointer<UInt8>(buf!.bytes)
WebSocket.writeUint16(buffer, offset: 0, value: code)
dequeueWrite(NSData(bytes: buffer, length: sizeof(UInt16)), code: .ConnectionClose)
}
///used to write things to the stream
Expand All @@ -678,13 +702,11 @@ public class WebSocket : NSObject, NSStreamDelegate {
buffer[1] = CUnsignedChar(dataLength)
} else if dataLength <= Int(UInt16.max) {
buffer[1] = 126
let sizeBuffer = UnsafeMutablePointer<UInt16>((buffer+offset))
sizeBuffer[0] = UInt16(dataLength).bigEndian
WebSocket.writeUint16(buffer, offset: offset, value: UInt16(dataLength))
offset += sizeof(UInt16)
} else {
buffer[1] = 127
let sizeBuffer = UnsafeMutablePointer<UInt64>((buffer+offset))
sizeBuffer[0] = UInt64(dataLength).bigEndian
WebSocket.writeUint64(buffer, offset: offset, value: UInt64(dataLength))
offset += sizeof(UInt64)
}
buffer[1] |= s.MaskMask
Expand Down