// *

// *****************************************************************************

// *

// * Copyright (c) 2025 Deskasoft International

// *

// * Permission is hereby granted, free of charge, to any person obtaining a copy

// * of this software and associated documentation files (the "Software"), to deal

// * in the Software without restriction, including without limitation the rights

// * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

// * copies of the Software, and to permit persons to whom the Software is

// * furnished to do so, subject to the following conditions:

// *

// * The above copyright notice and this permission notice shall be included in all

// * copies or substantial portions of the Software.

// *

// * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

// * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

// * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

// * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

// * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

// * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

// * SOFTWARE.

// *

// *

// * Please refer to LICENSE file.

// *

// ******************************************************************************

// *

using System;

using System.Threading;

using System.Threading.Tasks;

namespace HashifyNet.Core

{

/// <summary>

/// Abstract implementation of an <see cref="IHashFunction{FName}"/>.

/// Provides convenience checks and ensures a default HashSize has been set at construction.

/// </summary>

public abstract class HashFunctionBase<CName>

: IHashFunction<CName> where CName : IHashConfig<CName>

{

/// <summary>

/// <inheritdoc/>

/// </summary>

public abstract CName Config { get; }

IHashConfigBase IHashFunctionBase.Config => Config;

/// <summary>

/// <inheritdoc/>

/// </summary>

/// <param name="data"><inheritdoc/></param>

/// <returns><inheritdoc/></returns>

public IHashValue ComputeHash(byte[] data) =>

ComputeHash(data, CancellationToken.None);

/// <summary>

/// <inheritdoc/>

/// </summary>

/// <param name="data"><inheritdoc/></param>

/// <param name="cancellationToken"><inheritdoc/></param>

/// <returns><inheritdoc/></returns>

/// <exception cref="ArgumentNullException"><inheritdoc/></exception>

public IHashValue ComputeHash(byte[] data, CancellationToken cancellationToken)

{

if (data == null)

{

throw new ArgumentNullException(nameof(data));

}

return ComputeHash(data, 0, data.Length, cancellationToken);

}

/// <summary>

/// <inheritdoc/>

/// </summary>

/// <param name="data"><inheritdoc/></param>

/// <param name="offset"><inheritdoc/></param>

/// <param name="count"><inheritdoc/></param>

/// <returns><inheritdoc/></returns>

public IHashValue ComputeHash(byte[] data, int offset, int count) =>

ComputeHash(data, offset, count, CancellationToken.None);

/// <summary>

/// <inheritdoc/>

/// </summary>

/// <param name="data"><inheritdoc/></param>

/// <param name="offset"><inheritdoc/></param>

/// <param name="count"><inheritdoc/></param>

/// <param name="cancellationToken"><inheritdoc/></param>

/// <returns><inheritdoc/></returns>

/// <exception cref="ArgumentNullException"><inheritdoc/></exception>

/// <exception cref="ArgumentOutOfRangeException"><inheritdoc/></exception>

public IHashValue ComputeHash(byte[] data, int offset, int count, CancellationToken cancellationToken)

{

if (data == null)

{

throw new ArgumentNullException(nameof(data));

}

return ComputeHash(data.AsSpan(offset, count), cancellationToken);

}

/// <summary>

/// <inheritdoc/>

/// </summary>

/// <param name="data"><inheritdoc/></param>

/// <returns><inheritdoc/></returns>

public IHashValue ComputeHash(ReadOnlySpan<byte> data) =>

ComputeHash(data, CancellationToken.None);

/// <summary>

/// <inheritdoc/>

/// </summary>

/// <param name="data"><inheritdoc/></param>

/// <param name="cancellationToken"><inheritdoc/></param>

/// <returns>

/// <inheritdoc/>

/// </returns>

/// <exception cref="TaskCanceledException"><inheritdoc/></exception>

public IHashValue ComputeHash(ReadOnlySpan<byte> data, CancellationToken cancellationToken) =>

ComputeHashInternal(data, cancellationToken);

/// <summary>

/// Computes hash value for given read-only span.

/// </summary>

/// <param name="data">Span of the data to hash.</param>

/// <param name="cancellationToken">A cancellation token to observe while calculating the hash value.</param>

/// <returns>

/// Hash value of the data.

/// </returns>

/// <exception cref="TaskCanceledException">The <paramref name="cancellationToken"/> was canceled.</exception>

protected abstract IHashValue ComputeHashInternal(ReadOnlySpan<byte> data, CancellationToken cancellationToken);

}

}