EvilBeaver/OneScript: Исполняющая среда скриптов на языке 1С

src/OneScript.StandardLibrary/Hash/HashImpl.cs
150 строк5 KB
EvilBeaver
Рефакторинг стандартной библиотеки, нейспейсов и глобальных контекстов
29 янв 2020, 12:06
29 янв 2020, 12:06375e9f2
/*----------------------------------------------------------
This Source Code Form is subject to the terms of the 
Mozilla Public License, v.2.0. If a copy of the MPL 
was not distributed with this file, You can obtain one 
at http://mozilla.org/MPL/2.0/.
----------------------------------------------------------*/

using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;
using OneScript.StandardLibrary.Binary;
using ScriptEngine.Machine;
using ScriptEngine.Machine.Contexts;

namespace OneScript.StandardLibrary.Hash
{
    [ContextClass("ХешированиеДанных", "DataHashing")]
    public class HashImpl : AutoContext<HashImpl>, IDisposable
    {
        protected HashAlgorithm _provider;
        protected IValue _enumValue;
        protected CombinedStream _toCalculate=new CombinedStream();
        protected bool _calculated;
        protected byte[] _hash;

        public HashImpl(HashAlgorithm provider, IValue enumValue)
        {
            _provider = provider;
            _enumValue = enumValue;
            _calculated = false;
        }

        public byte[] InternalHash
        {
            get
            {
                if (!_calculated)
                {
                    _hash = _provider.ComputeHash(_toCalculate);
                    _calculated = true;
                }
                return _hash;
            }
        }

        [ContextProperty("ХешФункция", "HashFunction")]
        public IValue Extension
        {
            get
            {
                return _enumValue;
            }
        }

        [ContextProperty("ХешСумма", "HashSum")]
        public IValue Hash
        {
            get
            {
                if (_provider is Crc32)
                {
                    var buffer = new byte[4];
                    Array.Copy(InternalHash, buffer, 4);
                    if (BitConverter.IsLittleEndian)
                        Array.Reverse(buffer);
                    var ret = BitConverter.ToUInt32(buffer, 0);
                    return ValueFactory.Create((decimal)ret);
                }
                return new BinaryDataContext(InternalHash);
            }
        }

        [ContextProperty("ХешСуммаСтрокой", "HashSumOfString")]
        public string HashString
        {
            get
            {
                StringBuilder sb = new StringBuilder();
                for (int i = 0; i < InternalHash.Length; i++)
                    sb.Append(InternalHash[i].ToString("X2"));
                return sb.ToString();
            }
        }


        [ContextMethod("Добавить", "Append")]
        public void Append(IValue toAdd, uint count = 0)
        {
            switch (toAdd.DataType)
            {
                case DataType.String:
                    AddStream(new MemoryStream(Encoding.UTF8.GetBytes(toAdd.AsString())));
                    break;
                case DataType.Object when toAdd is GenericStream stream:
                    var length = Math.Min(count == 0 ? stream.Size() : count, stream.Size() - stream.CurrentPosition());
                    var buffer = (stream.GetUnderlyingStream() as MemoryStream)?.GetBuffer();
                    if (buffer == null)
                        throw RuntimeException.InvalidArgumentValue();
                    AddStream(new MemoryStream(buffer, (int) stream.CurrentPosition(), (int) length));
                    stream.Seek((int) length, StreamPositionEnum.Current);
                    break;
                case DataType.Object when toAdd is BinaryDataContext binaryData:
                    AddStream(new MemoryStream(binaryData.Buffer));
                    break;
                default:
                    throw RuntimeException.InvalidArgumentType();
            }
        }

        [ContextMethod("ДобавитьФайл", "AppendFile")]
        public void AppendFile(string path)
        {
            if (!File.Exists(path))
                throw RuntimeException.InvalidArgumentType();
            AddStream(new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.ReadWrite));
        }

        [ContextMethod("Очистить", "Clear")]
        public void Clear()
        {
            _toCalculate.Close();
            _toCalculate.Dispose();
            _toCalculate = new CombinedStream();
            _calculated = false;
        }


        [ScriptConstructor(Name = "По указанной хеш-функции")]
        public static HashImpl Constructor(IValue providerEnum)
        {
            var objectProvider = HashFunctionEnum.GetProvider(providerEnum);
            return new HashImpl(objectProvider, providerEnum);
        }

        public void Dispose()
        {
            _toCalculate.Close();
            _toCalculate.Dispose();
        }

        private void AddStream(Stream stream)
        {
            _toCalculate.AddStream(stream);
            _toCalculate.Seek(0, SeekOrigin.Begin);
            _calculated = false;
            
        }
    }
}