// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System;

namespace Microsoft.Diagnostics.DataContractReader.Contracts.StackWalkHelpers.X86;

internal static class CallPattern
{

    /// <summary>
    /// based on <a href="https://github.com/dotnet/runtime/blob/main/src/coreclr/inc/gcdecoder.cpp">src\inc\gcdecoder.cpp</a> DecodeCallPattern
    /// </summary>
    public static void DecodeCallPattern(uint pattern, out uint argCnt, out uint regMask, out uint argMask, out uint codeDelta)
    {
        uint val = CallPatternTable[(int)pattern];
        byte[] fld = BitConverter.GetBytes(val);
        argCnt = fld[0];
        regMask = fld[1];      // EBP,EBX,ESI,EDI
        argMask = fld[2];
        codeDelta = fld[3];
    }

    /// <summary>
    /// based on <a href="https://github.com/dotnet/runtime/blob/main/src/coreclr/inc/gcdecoder.cpp">src\inc\gcdecoder.cpp</a> CallCommonDelta
    /// </summary>
    public static ReadOnlySpan<uint> CallCommonDelta => [6, 8, 10, 12];

    /// <summary>
    /// based on <a href="https://github.com/dotnet/runtime/blob/main/src/coreclr/inc/gcdecoder.cpp">src\inc\gcdecoder.cpp</a> CallPatternTable
    /// </summary>
    private static ReadOnlySpan<uint> CallPatternTable =>
    [
        0x0a000200, //   30109
        0x0c000200, //   22970
        0x0c000201, //   19005
        0x0a000300, //   12193
        0x0c000300, //   10614
        0x0e000200, //   10253
        0x10000200, //    9746
        0x0b000200, //    9698
        0x0d000200, //    9625
        0x08000200, //    8909
        0x0c000301, //    8522
        0x11000200, //    7382
        0x0e000300, //    7357
        0x12000200, //    7139
        0x10000300, //    7062
        0x11000300, //    6970
        0x0a000201, //    6842
        0x0a000100, //    6803
        0x0f000200, //    6795
        0x13000200, //    6559
        0x08000300, //    6079
        0x15000200, //    5874
        0x0d000201, //    5492
        0x0c000100, //    5193
        0x0d000300, //    5165
        0x23000200, //    5143
        0x1b000200, //    5035
        0x14000200, //    4872
        0x0f000300, //    4850
        0x0a000700, //    4781
        0x09000200, //    4560
        0x12000300, //    4496
        0x16000200, //    4180
        0x07000200, //    4021
        0x09000300, //    4012
        0x0c000700, //    3988
        0x0c000600, //    3946
        0x0e000100, //    3823
        0x1a000200, //    3764
        0x18000200, //    3744
        0x17000200, //    3736
        0x1f000200, //    3671
        0x13000300, //    3559
        0x0a000600, //    3214
        0x0e000600, //    3109
        0x08000201, //    2984
        0x0b000300, //    2928
        0x0a000301, //    2859
        0x07000100, //    2826
        0x13000100, //    2782
        0x09000301, //    2644
        0x19000200, //    2638
        0x11000700, //    2618
        0x21000200, //    2518
        0x0d000202, //    2484
        0x10000100, //    2480
        0x0f000600, //    2413
        0x14000300, //    2363
        0x0c000500, //    2362
        0x08000301, //    2285
        0x20000200, //    2245
        0x10000700, //    2240
        0x0f000100, //    2236
        0x1e000200, //    2214
        0x0c000400, //    2193
        0x16000300, //    2171
        0x12000600, //    2132
        0x22000200, //    2011
        0x1d000200, //    2011
        0x0c000f00, //    1996
        0x0e000700, //    1971
        0x0a000400, //    1970
        0x09000201, //    1932
        0x10000600, //    1903
        0x15000300, //    1847
        0x0a000101, //    1814
        0x0a000b00, //    1771
        0x0c000601, //    1737
        0x09000700, //    1737
        0x07000300, //    1684
    ];
}