New: Implemented Torrent Download Clients: uTorrent, Transmission and Deluge. And several public and private Torrent Indexers.

src/MonoTorrent/BEncoding/BEncodedNumber.cs

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+using System;
+using System.IO;
+using System.Text;
+using System.Collections.Generic;
+
+namespace MonoTorrent.BEncoding
+{
+    /// <summary>
+    /// Class representing a BEncoded number
+    /// </summary>
+    public class BEncodedNumber : BEncodedValue, IComparable<BEncodedNumber>
+    {
+        #region Member Variables
+        /// <summary>
+        /// The value of the BEncodedNumber
+        /// </summary>
+        public long Number
+        {
+            get { return number; }
+            set { number = value; }
+        }
+        internal long number;
+        #endregion
+
+
+        #region Constructors
+        public BEncodedNumber()
+            : this(0)
+        {
+        }
+
+        /// <summary>
+        /// Create a new BEncoded number with the given value
+        /// </summary>
+        /// <param name="initialValue">The inital value of the BEncodedNumber</param>
+        public BEncodedNumber(long value)
+        {
+            this.number = value;
+        }
+
+        public static implicit operator BEncodedNumber(long value)
+        {
+            return new BEncodedNumber(value);
+        }
+        #endregion
+
+
+        #region Encode/Decode Methods
+
+        /// <summary>
+        /// Encodes this number to the supplied byte[] starting at the supplied offset
+        /// </summary>
+        /// <param name="buffer">The buffer to write the data to</param>
+        /// <param name="offset">The offset to start writing the data at</param>
+        /// <returns></returns>
+        public override int Encode(byte[] buffer, int offset)
+        {
+            long number = this.number;
+
+            int written = offset;
+            buffer[written++] = (byte)'i';
+            
+            if (number < 0)
+            {
+                buffer[written++] = (byte)'-';
+                number = -number;
+            }
+            // Reverse the number '12345' to get '54321'
+            long reversed = 0;
+            for (long i = number; i != 0; i /= 10)
+                reversed = reversed * 10 + i % 10;
+
+            // Write each digit of the reversed number to the array. We write '1'
+            // first, then '2', etc
+            for (long i = reversed; i != 0; i /= 10)
+                buffer[written++] = (byte)(i % 10 + '0');
+
+            if (number == 0)
+                buffer[written++] = (byte)'0';
+
+            // If the original number ends in one or more zeros, they are lost
+            // when we reverse the number. We add them back in here.
+            for (long i = number; i % 10 == 0 && number != 0; i /= 10)
+                buffer[written++] = (byte)'0';
+
+            buffer[written++] = (byte)'e';
+            return written - offset;
+        }
+
+
+        /// <summary>
+        /// Decodes a BEncoded number from the supplied RawReader
+        /// </summary>
+        /// <param name="reader">RawReader containing a BEncoded Number</param>
+        internal override void DecodeInternal(RawReader reader)
+        {
+            int sign = 1;
+            if (reader == null)
+                throw new ArgumentNullException("reader");
+
+            if (reader.ReadByte() != 'i')              // remove the leading 'i'
+                throw new BEncodingException("Invalid data found. Aborting.");
+
+            if (reader.PeekByte() == '-')
+            {
+                sign = -1;
+                reader.ReadByte ();
+            }
+
+            int letter;
+            while (((letter = reader.PeekByte()) != -1) && letter != 'e')
+            {
+                if(letter < '0' || letter > '9')
+                    throw new BEncodingException("Invalid number found.");
+                number = number * 10 + (letter - '0');
+                reader.ReadByte ();
+            }
+            if (reader.ReadByte() != 'e')        //remove the trailing 'e'
+                throw new BEncodingException("Invalid data found. Aborting.");
+
+            number *= sign;
+        }
+        #endregion
+
+
+        #region Helper Methods
+        /// <summary>
+        /// Returns the length of the encoded string in bytes
+        /// </summary>
+        /// <returns></returns>
+        public override int LengthInBytes()
+        {
+            long number = this.number;
+            int count = 2; // account for the 'i' and 'e'
+
+            if (number == 0)
+                return count + 1;
+
+            if (number < 0)
+            {
+                number = -number;
+                count++;
+            }
+            for (long i = number; i != 0; i /= 10)
+                count++;
+
+            return count;
+        }
+
+
+        public int CompareTo(object other)
+        {
+            if (other is BEncodedNumber || other is long || other is int)
+                return CompareTo((BEncodedNumber)other);
+
+            return -1;
+        }
+
+        public int CompareTo(BEncodedNumber other)
+        {
+            if (other == null)
+                throw new ArgumentNullException("other");
+
+            return this.number.CompareTo(other.number);
+        }
+
+
+        public int CompareTo(long other)
+        {
+            return this.number.CompareTo(other);
+        }
+        #endregion
+
+
+        #region Overridden Methods
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="obj"></param>
+        /// <returns></returns>
+        public override bool Equals(object obj)
+        {
+            BEncodedNumber obj2 = obj as BEncodedNumber;
+            if (obj2 == null)
+                return false;
+
+            return (this.number == obj2.number);
+        }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <returns></returns>
+        public override int GetHashCode()
+        {
+            return this.number.GetHashCode();
+        }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <returns></returns>
+        public override string ToString()
+        {
+            return (this.number.ToString());
+        }
+        #endregion
+    }
+}