Synnefo » Pithos MS Client

using System;

using System.Collections.Generic;

using System.Diagnostics.Contracts;

using System.Linq;

using System.Text;

using System.IO;

using System.Text.RegularExpressions;

using System.Threading.Tasks;

using Pithos.Network;

namespace Pithos.Core.Agents

{

    static class FileInfoExtensions

    {

        public static int Read(this FileInfo fileInfo,byte[] buffer,int offset,int count)

        {            

            //Open the stream only long enough to read a block

            using (var stream = fileInfo.OpenRead())

            {

                stream.Seek(offset, SeekOrigin.Begin);

                return  stream.Read(buffer, 0, count);                

            }

        }

        public static Task<int> ReadAsync(this FileInfo fileInfo, byte[] buffer, int offset, int count)

        {

            //The using statement is not used because we will work asyncronously

            var stream = FileAsync.OpenRead(fileInfo.FullName);

            try

            {

                stream.Seek(offset, SeekOrigin.Begin);

                var read = stream.ReadAsync(buffer, offset, count);

                return read.ContinueWith(t =>

                {

                    //Make sure the stream closes

                    stream.Close();

                    stream = null;

                    t.PropagateExceptions();

                    return t.Result;

                });

            }

            catch (Exception)

            {

                //In case of error make sure we close the stream                

                //The stream may have been 

                if (stream!=null)

                    stream.Close();

                throw;

            }

        }

        public static string CalculateHash(this FileInfo info,int blockSize,string algorithm)

        {

            if (info==null)

                throw new ArgumentNullException("info");

            if (String.IsNullOrWhiteSpace(info.FullName))

                throw new ArgumentException("info");

            if (blockSize<=0)

                throw new ArgumentOutOfRangeException("blockSize",blockSize,"blockSize must be greater than 0");

            if (String.IsNullOrWhiteSpace(algorithm))

                throw new ArgumentNullException("algorithm");

            Contract.EndContractBlock();

            if (info.Length <= blockSize)

                return Signature.CalculateMD5(info.FullName);

            else

                return Signature.CalculateTreeHash(info.FullName, blockSize, algorithm).TopHash.ToHashString();

        }

    }

}