I have a Swift wrapper for the expat XML parser, and I just went through the update to Swift 3, and I'm thrown a series of errors that mostly appear to be of two types. Here is a representative function of the first type:
func parse() throws {
var done = false
while !done {
let buffer: UnsafeMutablePointer<Void> = XML_GetBuffer(parser, Int32(bufsize))
if buffer == nil {
let errorCode = XML_GetErrorCode(parser)
throw ExpatError(reason: "Error \(errorCode), \(XML_ErrorString(errorCode))")
}
let bytesRead = readData(UnsafeMutablePointer<UInt8>(buffer), bufferLength: bufsize)
done = bytesRead < bufsize
if XML_ParseBuffer(parser, Int32(bytesRead), Int32(done ? 1 : 0)) != XML_STATUS_OK {
let errorCode = XML_GetErrorCode(parser)
throw ExpatError(reason: "Error \(errorCode), \(XML_ErrorString(errorCode))")
}
}
}
Xcode 8's migrator changed the declaration of buffer to UnsafeMutableRawPointer?, but the readData call gives an error:
Cannot invoke initializer for type 'UnsafeMutablePointer<UInt8>' with an argument list of type '(UnsafeMutableRawPointer?)'
Pointer conversion restricted: use '.assumingMemoryBound(to:)' or '.bindMemory(to:capacity:)' to view memory as a type.
Overloads for 'UnsafeMutablePointer<UInt8>' exist with these partially matching parameter lists: (RawPointer), (OpaquePointer), (OpaquePointer?), (UnsafeMutablePointer<Pointee>), (UnsafeMutablePointer<Pointee>?)
Where can I read up on how to make the conversion? My initial effort is:
let bytesRead = readData(buffer!.bindMemory(to: UInt8.self, capacity: bufsize), bufferLength: bufsize)
That's more or less thrashing around with no real understanding.
The second type is turning a closure into the appropriate C function pointer. For example:
XML_SetEndElementHandler(parser) { (userData: UnsafeMutableRawPointer, name: UnsafePointer<XML_Char>) -> Void in
let theParser = unsafeBitCast(userData, to: ExpatSwift.self)
let theName = ExpatSwift.getString(name)
theParser.endElement(theName)
}
This gets an error:
Cannot convert value of type '(UnsafeMutableRawPointer, UnsafePointer<XML_Char>) -> Void' to expected argument type 'XML_EndElementHandler!'
XML_EndElementHandler is defined as:
typedef void (XMLCALL *XML_EndElementHandler) (void *userData,
const XML_Char *name);
Here I have no real clue as to how to fix it.
So, any pointers to either how to fix these problems or to a good source to read to understand them?
John
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John Brownie
In Finland on furlough from SIL Papua New Guinea