using System;

using System.Collections.Generic;

using System.Diagnostics.Contracts;

using ReClassNET.MemoryScanner.Comparer;

namespace ReClassNET.MemoryScanner

{

internal class ScannerWorker

{

private readonly ScanSettings settings;

private readonly IScanComparer comparer;

public ScannerWorker(ScanSettings settings, IScanComparer comparer)

{

Contract.Requires(settings != null);

Contract.Requires(comparer != null);

this.settings = settings;

this.comparer = comparer;

}

/// <summary>

/// Uses the <see cref="IScanComparer"/> to scan the byte array for results.

/// </summary>

/// <param name="data">The data to scan.</param>

/// <param name="count">The length of the <paramref name="data"/> parameter.</param>

/// <returns>An enumeration of all <see cref="ScanResult"/>s.</returns>

public IEnumerable<ScanResult> Search(byte[] data, int count)

{

Contract.Requires(data != null);

var endIndex = count - comparer.ValueSize;

for (var i = 0; i < endIndex; i += settings.FastScanAlignment)

{

if (comparer.Compare(data, i, out var result))

{

result.Address = (IntPtr)i;

yield return result;

}

}

}

/// <summary>

/// Uses the <see cref="IScanComparer"/> to scan the byte array for results.

/// The comparer uses the provided previous results to compare to the current value.

/// </summary>

/// <param name="data">The data to scan.</param>

/// <param name="count">The length of the <paramref name="data"/> parameter.</param>

/// <param name="results">The previous results to use.</param>

/// <returns>An enumeration of all <see cref="ScanResult"/>s.</returns>

public IEnumerable<ScanResult> Search(byte[] data, int count, IEnumerable<ScanResult> results)

{

Contract.Requires(data != null);

Contract.Requires(results != null);

var endIndex = count - comparer.ValueSize;

foreach (var previous in results)

{

var offset = previous.Address.ToInt32();

if (offset <= endIndex)

{

if (comparer.Compare(data, offset, previous, out var result))

{

result.Address = previous.Address;

yield return result;

}

}

}

}

}

}