PKHeX/PKHeX.Core/Saves/Substructures/Gen4/SAV4BlockDetection.cs
Kurt fc754b346b
File scoped namespaces (#3529)
[Language Reference](https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/proposals/csharp-10.0/file-scoped-namespaces)

Updates all the files, one less level of indentation.

Some small changes were made to API surfaces, renaming `PKM pkm` -> `PKM pk`, and `LegalityAnalysis.pkm` -> `LegalityAnalysis.Entity`
2022-06-18 11:04:24 -07:00

51 lines
1.7 KiB
C#

using System;
using static System.Buffers.Binary.BinaryPrimitives;
namespace PKHeX.Core;
/// <summary>
/// Finds the index of the most recent save block for <see cref="SAV4"/> blocks.
/// </summary>
public static class SAV4BlockDetection
{
private const int First = 0;
private const int Second = 1;
private const int Same = 2;
/// <summary>
/// Compares the footers of the two blocks to determine which is newest.
/// </summary>
/// <returns>0=Primary, 1=Secondary.</returns>
public static int CompareFooters(ReadOnlySpan<byte> data, int offset1, int offset2)
{
// Major Counters
var major1 = ReadUInt32LittleEndian(data[offset1..]);
var major2 = ReadUInt32LittleEndian(data[offset2..]);
var result1 = CompareCounters(major1, major2);
if (result1 != Same)
return result1;
// Minor Counters
var minor1 = ReadUInt32LittleEndian(data[(offset1 + 4)..]);
var minor2 = ReadUInt32LittleEndian(data[(offset2 + 4)..]);
var result2 = CompareCounters(minor1, minor2);
return result2 == Second ? Second : First; // Same -> First, shouldn't happen for valid saves.
}
private static int CompareCounters(uint counter1, uint counter2)
{
// Uninitialized -- only continue if a rollover case (humanly impossible)
if (counter1 == uint.MaxValue && counter2 != uint.MaxValue - 1)
return Second;
if (counter2 == uint.MaxValue && counter1 != uint.MaxValue - 1)
return First;
// Different
if (counter1 > counter2)
return First;
if (counter1 < counter2)
return Second;
return Same;
}
}