Cpp2IL/Cpp2IL.Core/Extensions/MiscExtensions.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Gee.External.Capstone.Arm;
using Gee.External.Capstone.Arm64;
using Iced.Intel;
using Instruction = Iced.Intel.Instruction;

namespace Cpp2IL.Core.Extensions;

public static class MiscExtensions
{
    public static ISIL.Register MakeIndependent(this Register reg) => new ISIL.Register(null, reg.ToString().ToLower());

    public static ulong GetImmediateSafe(this Instruction instruction, int op) => instruction.GetOpKind(op).IsImmediate() ? instruction.GetImmediate(op) : 0;

    public static bool IsJump(this Mnemonic mnemonic) => mnemonic is Mnemonic.Call or >= Mnemonic.Ja and <= Mnemonic.Js;
    public static bool IsConditionalJump(this Mnemonic mnemonic) => mnemonic.IsJump() && mnemonic != Mnemonic.Jmp && mnemonic != Mnemonic.Call;

    //Arm Extensions
    public static ArmRegister? RegisterSafe(this ArmOperand operand) => operand.Type != ArmOperandType.Register ? null : operand.Register;
    public static bool IsImmediate(this ArmOperand operand) => operand.Type is ArmOperandType.CImmediate or ArmOperandType.Immediate or ArmOperandType.PImmediate;
    public static int ImmediateSafe(this ArmOperand operand) => operand.IsImmediate() ? operand.Immediate : 0;
    private static ArmOperand? MemoryOperand(ArmInstruction instruction) => instruction.Details.Operands.FirstOrDefault(a => a.Type == ArmOperandType.Memory);

    public static ArmRegister? MemoryBase(this ArmInstruction instruction) => MemoryOperand(instruction)?.Memory.Base;
    public static ArmRegister? MemoryIndex(this ArmInstruction instruction) => MemoryOperand(instruction)?.Memory.Index;
    public static int MemoryOffset(this ArmInstruction instruction) => MemoryOperand(instruction)?.Memory.Displacement ?? 0;

    //Arm64 Extensions
    public static Arm64Register? RegisterSafe(this Arm64Operand operand) => operand.Type != Arm64OperandType.Register ? null : operand.Register;
    public static bool IsImmediate(this Arm64Operand operand) => operand.Type is Arm64OperandType.CImmediate or Arm64OperandType.Immediate;
    public static long ImmediateSafe(this Arm64Operand operand) => operand.IsImmediate() ? operand.Immediate : 0;
    internal static Arm64Operand? MemoryOperand(this Arm64Instruction instruction) => instruction.Details.Operands.FirstOrDefault(a => a.Type == Arm64OperandType.Memory);

    public static Arm64Register? MemoryBase(this Arm64Instruction instruction) => instruction.MemoryOperand()?.Memory.Base;
    public static Arm64Register? MemoryIndex(this Arm64Instruction instruction) => instruction.MemoryOperand()?.Memory.Index;
    public static int MemoryOffset(this Arm64Instruction instruction) => instruction.MemoryOperand()?.Memory.Displacement ?? 0;

    public static bool IsConditionalMove(this Instruction instruction)
    {
        switch (instruction.Mnemonic)
        {
            case Mnemonic.Cmove:
            case Mnemonic.Cmovne:
            case Mnemonic.Cmovs:
            case Mnemonic.Cmovns:
            case Mnemonic.Cmovg:
            case Mnemonic.Cmovge:
            case Mnemonic.Cmovl:
            case Mnemonic.Cmovle:
            case Mnemonic.Cmova:
            case Mnemonic.Cmovae:
            case Mnemonic.Cmovb:
            case Mnemonic.Cmovbe:
                return true;
            default:
                return false;
        }
    }

    public static Stack<T> Clone<T>(this Stack<T> original)
    {
        var arr = new T[original.Count];
        original.CopyTo(arr, 0);
        Array.Reverse(arr);
        return new Stack<T>(arr);
    }

    public static List<T> Clone<T>(this List<T> original)
    {
        var arr = new T[original.Count];
        original.CopyTo(arr, 0);
        return [.. arr];
    }

    public static Dictionary<T1, T2> Clone<T1, T2>(this Dictionary<T1, T2> original) where T1 : notnull
        => new(original);

    public static T[] SubArray<T>(this T[] data, int index, int length) => data.SubArray(index..(index + length));

    public static T RemoveAndReturn<T>(this List<T> data, int index)
    {
        var result = data[index];
        data.RemoveAt(index);
        return result;
    }

    public static IEnumerable<T> Repeat<T>(this T t, int count)
    {
        for (int i = 0; i < count; i++)
        {
            yield return t;
        }
    }

    public static string Repeat(this string source, int count)
    {
        var res = new StringBuilder();
        for (var i = 0; i < count; i++)
        {
            res.Append(source);
        }

        return res.ToString();
    }

    internal static T[] SubArray<T>(this T[] source, Range range)
    {
        if (!range.Start.IsFromEnd && !range.End.IsFromEnd)
            if (range.Start.Value > range.End.Value)
                throw new Exception($"Range {range} - Start must be less than end, when both are fixed offsets");

        var (offset, len) = range.GetOffsetAndLength(source.Length);
        var dest = new T[len];

        Array.Copy(source, offset, dest, 0, len);

        return dest;
    }

    public static T? GetValueSafely<T>(this T[] arr, int i) where T : class
    {
        if (i >= arr.Length)
            return null;

        return arr[i];
    }

    public static bool IsImmediate(this OpKind opKind) => opKind is >= OpKind.Immediate8 and <= OpKind.Immediate32to64;


    public static void TrimEndWhile<T>(this List<T> instructions, Func<T, bool> predicate)
    {
        var i = instructions.Count - 1;
        for (; i >= 0; i--)
        {
            if (!predicate(instructions[i]))
            {
                break;
            }
        }

        var toRemove = instructions.Count - 1 - i;

        if (toRemove <= 0)
            return;

        instructions.RemoveRange(i, toRemove);
    }

    public static IEnumerable<T> Peek<T>(this IEnumerable<T> enumerable, Action<T> action)
    {
        return enumerable.Select(t =>
        {
            action(t);
            return t;
        });
    }

    public static unsafe uint ReadUInt(this ReadOnlySpan<byte> span, int start)
    {
        if (start >= span.Length)
            throw new ArgumentOutOfRangeException(nameof(start), $"start=[{start}], mem.Length=[{span.Length}]");
        fixed (byte* ptr = &span[start])
            return *(uint*)ptr;
    }

    public static bool BitsAreEqual(this BitArray first, BitArray second)
    {
        if (first.Count != second.Count)
            return false;

        bool areDifferent = false;
        for (int i = 0; i < first.Count && !areDifferent; i++)
            areDifferent = first.Get(i) != second.Get(i);

        return !areDifferent;
    }
}