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Simplified the inlined type cast state. Now it's time to try the integer sign part. 

Signed-off-by: Adam Rocska <adam.rocska@adams.solutions>
This commit is contained in:
Adam Rocska 2020-05-04 10:52:44 +02:00
parent bee57f211a
commit a9dd03de70
1 changed files with 17 additions and 23 deletions
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40
Sources/MaxMindDBReader/NumericDecoder.swift
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@ -14,40 +14,34 @@ class NumericDecoder {
init(inputEndianness: Endianness) { self.input = inputEndianness }
private func padded<T>(_ data: Data) -> T where T: FixedWidthInteger {
let byteCount = MemoryLayout<T>.size - data.count
let padBytes = Data(count: byteCount)
let padBytes = Data(count: MemoryLayout<T>.size - data.count)
var wellSizedData: Data = input == .big ? padBytes + data : data + padBytes
return UnsafeRawPointer(&wellSizedData).load(as: T.self)
}
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),
upper: data.endIndex
)
: (
lower: data.startIndex,
upper: data.limitedIndex(data.startIndex, offsetBy: byteCount)
)
let bounds: (lower: Range<Data.Index>.Bound, upper: Range<Data.Index>.Bound)
if input == .big {
bounds = (
lower: data.limitedIndex(data.endIndex, offsetBy: -MemoryLayout<T>.size),
upper: data.endIndex
)
} else {
bounds = (
lower: data.startIndex,
upper: data.limitedIndex(data.startIndex, offsetBy: MemoryLayout<T>.size)
)
}
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
switch strayBytes {
case _ where strayBytes > 0:
return padded(data)
case _ where strayBytes < 0:
return truncated(data)
default:
var wellSizedData: Data = data
return UnsafeRawPointer(&wellSizedData).load(as: T.self)
}
if strayBytes > 0 { return padded(data) }
if strayBytes < 0 { return truncated(data) }
var wellSizedData: Data = data
return UnsafeRawPointer(&wellSizedData).load(as: T.self)
}
func decode<T>(_ data: Data) -> T where T: FixedWidthInteger {