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Last try before dumping & preconditioning: Moved the typed value contruction into the padding & truncating functions. Here the integer signed cases could be handled properly. 

Signed-off-by: Adam Rocska <adam.rocska@adams.solutions>
This commit is contained in:
Adam Rocska 2020-05-04 10:44:41 +02:00
parent 438c0eca44
commit bee57f211a
1 changed files with 15 additions and 11 deletions
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26
Sources/MaxMindDBReader/NumericDecoder.swift
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@ -13,12 +13,16 @@ class NumericDecoder {
init(inputEndianness: Endianness) { self.input = inputEndianness }
private func pad(_ data: Data, byteCount: Int) -> Data {
let padBytes = Data(count: byteCount)
return input == .big ? padBytes + data : data + padBytes
private func padded<T>(_ data: Data) -> T where T: FixedWidthInteger {
let byteCount = MemoryLayout<T>.size - data.count
let padBytes = Data(count: byteCount)
var wellSizedData: Data = input == .big ? padBytes + data : data + padBytes
return UnsafeRawPointer(&wellSizedData).load(as: T.self)
}
private func truncate(_ data: Data, byteCount: Int) -> Data {
private func truncated<T>(_ data: Data) -> T where T: FixedWidthInteger {
let byteCount = MemoryLayout<T>.size
let bounds = input == .big
? (
lower: data.limitedIndex(data.endIndex, offsetBy: -byteCount),
@ -28,22 +32,22 @@ class NumericDecoder {
lower: data.startIndex,
upper: data.limitedIndex(data.startIndex, offsetBy: byteCount)
)
return data.subdata(in: Range(uncheckedBounds: bounds))
var wellSizedData: Data = data.subdata(in: Range(uncheckedBounds: bounds))
return UnsafeRawPointer(&wellSizedData).load(as: T.self)
}
private func unpack<T>(_ data: Data) -> T where T: FixedWidthInteger {
let strayBytes = MemoryLayout<T>.size - data.count
var wellSizedData: Data
/// TODO : Move the unsafe raw pointer based type creation into truncate & pad. That way we can handle the php monkeys' integer signing problem
switch strayBytes {
case _ where strayBytes > 0:
wellSizedData = pad(data, byteCount: strayBytes)
return padded(data)
case _ where strayBytes < 0:
wellSizedData = truncate(data, byteCount: MemoryLayout<T>.size)
return truncated(data)
default:
wellSizedData = data
var wellSizedData: Data = data
return UnsafeRawPointer(&wellSizedData).load(as: T.self)
}
return UnsafeRawPointer(&wellSizedData).load(as: T.self)
}
func decode<T>(_ data: Data) -> T where T: FixedWidthInteger {