/lib/otp.net/Otp/OtpOutputStream.cs

/*``The contents of this file are subject to the Erlang Public License,
* Version 1.1, (the "License"); you may not use this file except in
* compliance with the License. You should have received a copy of the
* Erlang Public License along with this software. If not, it can be
* retrieved via the world wide web at http://www.erlang.org/.
* 
* Software distributed under the License is distributed on an "AS IS"
* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
* the License for the specific language governing rights and limitations
* under the License.
* 
* The Initial Developer of the Original Code is Ericsson Utvecklings AB.
* Portions created by Ericsson are Copyright 1999, Ericsson Utvecklings
* AB. All Rights Reserved.''
* 
 * Converted from Java to C# by Vlad Dumitrescu (vlad_Dumitrescu@hotmail.com)
*/
namespace Otp
{
	using System;

	/*
	* Provides a stream for encoding Erlang terms to external format, for
	* transmission or storage.
	* 
	* <p> Note that this class is not synchronized, if you need
	* synchronization you must provide it yourself.
	*
	**/
	public class OtpOutputStream
	{
		/*The default initial size of the stream. **/
		public const int defaultInitialSize = 2048;
		
		/*The default increment used when growing the stream. **/
		public const int defaultIncrement = 2048;
		
		private byte[] buf = null;
		private int _size = 0;
		private int _count = 0;

		/*
		* Create a stream with the default initial size.
		**/
		public OtpOutputStream():this(defaultInitialSize)
		{
		}
		
		/*
		* Create a stream with the specified initial size.
		**/
		public OtpOutputStream(int size)
		{
			this._size = size;
			buf = new byte[size];
			_count = 0;
		}
		
		/*
		* Create a stream containing the encoded version of the given
		* Erlang term.
		**/
		public OtpOutputStream(Erlang.Object o):this()
		{
			this.write_any(o);
		}
		
		// package scope
		/*
		* Get the contents of the output stream as an input stream instead.
		* This is used internally in {@link OtpCconnection} for tracing
		* outgoing packages.
		*
		* @param offset where in the output stream to read data from when
		* creating the input stream. The offset is necessary because header
		* contents start 5 bytes into the header buffer, whereas payload
		* contents start at the beginning
		*
		* @return an input stream containing the same raw data.
		**/
		internal virtual OtpInputStream getOtpInputStream(int offset)
		{
			return new OtpInputStream(buf, offset, _count - offset);
		}
		
		/*
		* Reset the stream so that it can be reused.
		**/
		public virtual void  reset()
		{
			_count = 0;
		}
		
		/*
		* Get the current position in the stream.
		*
		* @return the current position in the stream.
		**/
		public virtual int getPos()
		{
			return _count;
		}

		/*
		* Write one byte to the stream.
		*
		* @param b the byte to write.
		*
		**/
		public virtual void  write(byte b)
		{
			if (_count >= _size)
			{
				// System.err.println("Expanding buffer from " + size + " to " + size + defaultIncrement);
				byte[] tmp = new byte[_size + defaultIncrement];
				Array.Copy(buf, 0, tmp, 0, _count);
				_size += defaultIncrement;
				buf = tmp;
			}
			
			buf[_count++] = b;
		}
		
		/*
		* Write an array of bytes to the stream.
		*
		* @param buf the array of bytes to write.
		*
		**/
		public virtual void  write(byte[] buf)
		{
			if (_count + buf.Length > _size)
			{
				// System.err.println("Expanding buffer from " +
				// size + " to " + buf.length + size + defaultIncrement);
				byte[] tmp = new byte[_size + buf.Length + defaultIncrement];
				Array.Copy(this.buf, 0, tmp, 0, _count);
				_size += defaultIncrement + buf.Length;
				this.buf = tmp;
			}
			
			Array.Copy(buf, 0, this.buf, _count, buf.Length);
			_count += (int) (buf.Length);
		}
		
		/*
		* Write the contents of the stream to an OutputStream.
		*
		* @param os the OutputStream to write to.
		*
		* @exception C#.io.IOException if there is an error writing to
		* the OutputStream.
		**/
		public virtual void  writeTo(System.IO.Stream os)
		{
			os.Write(buf, 0, _count);
			os.Flush();
		}
		
		/*
		* Write the low byte of a value to the stream.
		*
		* @param n the value to use.
		*
		**/
		public virtual void  write1(long n)
		{
			write((byte) (n & 0xff));
		}
		
		/*
		* Write an array of bytes to the stream.
		*
		* @param buf the array of bytes to write.
		*
		**/
		public virtual void  writeN(byte[] bytes)
		{
			write(bytes);
		}
		
		/*
		* Get the current capacity of the stream. As bytes are added the
		* capacity of the stream is increased automatically, however this
		* method returns the current size.
		*
		* @return the size of the internal buffer used by the stream.
		**/
		public virtual int size()
		{
			return _size;
		}
		
		/*
		* Get the number of bytes in the stream.
		*
		* @return the number of bytes in the stream.
		**/
		public virtual int count()
		{
			return _count;
		}
		
		/*
		* Write the low two bytes of a value to the stream in big endian
		* order.
		*
		* @param n the value to use.
		**/
		public virtual void  write2BE(long n)
		{
			write((byte) ((n & 0xff00) >> 8));
			write((byte) (n & 0xff));
		}
		
		/*
		* Write the low four bytes of a value to the stream in big endian
		* order.
		*
		* @param n the value to use.
		**/
		public virtual void  write4BE(long n)
		{
			write((byte) ((n & 0xff000000) >> 24));
			write((byte) ((n & 0xff0000) >> 16));
			write((byte) ((n & 0xff00) >> 8));
			write((byte) (n & 0xff));
		}
		
		/*
		* Write the low two bytes of a value to the stream in little endian
		* order.
		*
		* @param n the value to use.
		**/
		public virtual void  write2LE(long n)
		{
			write((byte) (n & 0xff));
			write((byte) ((n & 0xff00) >> 8));
		}
		
		/*
		* Write the low four bytes of a value to the stream in little
		* endian order.
		*
		* @param n the value to use.
		**/
		public virtual void  write4LE(long n)
		{
			write((byte) (n & 0xff));
			write((byte) ((n & 0xff00) >> 8));
			write((byte) ((n & 0xff0000) >> 16));
			write((byte) ((n & 0xff000000) >> 24));
		}
		
		/*
		* Write the low four bytes of a value to the stream in bif endian
		* order, at the specified position. If the position specified is
		* beyond the end of the stream, this method will have no effect.
		*
		* Normally this method should be used in conjunction with {@link
		* #getPos() getPos()}, when is is necessary to insert data into the
		* stream before it is known what the actual value should be. For
		* example:
		*
		<pre>
		int pos = s.getPos();
		s.write4BE(0); // make space for length data,
		// but final value is not yet known
		
		[ ...more write statements...]
		
		// later... when we know the length value
		s.poke4BE(pos, length);
		</pre>
		
		*
		* @param offset the position in the stream.
		* @param n the value to use.
		**/
		public virtual void  poke4BE(int offset, long n)
		{
			if (offset < _count)
			{
				buf[offset + 0] = ((byte) ((n & 0xff000000) >> 24));
				buf[offset + 1] = ((byte) ((n & 0xff0000) >> 16));
				buf[offset + 2] = ((byte) ((n & 0xff00) >> 8));
				buf[offset + 3] = ((byte) (n & 0xff));
			}
		}
		
		/*
		* Write a string to the stream as an Erlang atom.
		*
		* @param atom the string to write.
		**/
		public virtual void  write_atom(System.String atom)
		{
			this.write1(OtpExternal.atomTag);
			this.write2BE(atom.Length);
			//UPGRADE_NOTE: This code will be optimized in the future;
			byte[] tmpBytes;
			int i;
			string tmpStr;
			tmpStr = atom;
			tmpBytes = new byte[tmpStr.Length];
			i = 0;
			while (i < tmpStr.Length)
			{
				tmpBytes[i] = (byte) tmpStr[i];
				i++;
			}
			this.writeN(tmpBytes);
		}
		
		/*
		* Write an array of bytes to the stream as an Erlang binary.
		*
		* @param bin the array of bytes to write.
		**/
		public virtual void  write_binary(byte[] bin)
		{
			this.write1(OtpExternal.binTag);
			this.write4BE(bin.Length);
			this.writeN(bin);
		}
		
		/*
		* Write a boolean value to the stream as the Erlang atom 'true' or
		* 'false'.
		*
		* @param b the boolean value to write.
		**/
		public virtual void  write_boolean(bool b)
		{
			this.write_atom(b.ToString());
		}
		
		/*
		* Write a single byte to the stream as an Erlang integer.
		*
		* @param b the byte to use.
		**/
		public virtual void  write_byte(byte b)
		{
			this.write_long(b);
		}
		
		/*
		* Write a character to the stream as an Erlang integer.
		*
		* @param c the character to use.
		**/
		public virtual void  write_char(char c)
		{
			this.write_long(c);
		}
		
		/*
		* Write a double value to the stream. 
		*
		* @param d the double to use.
		**/
		public virtual void  write_double(double d)
		{
			double val;
			int exp = 0;
			int sign = 0;
			System.String str;
			
			// remove sign to simplify decimal shift
			if (d >= 0)
			{
				val = d;
			}
			else
			{
				sign = 1;
				val = - d;
			}
			
			// move the decimal point until we have a single units digit
			if (System.Math.Sign(val) != 0)
			{
				// until greater than or equal to 1.0  -> multiply by 10
				while (val < 1.0)
				{
					val *= 10;
					exp--;
				}
				// until strictly less than 10.0 -> divide by 10
				while (val >= 10.0)
				{
					val /= 10;
					exp++;
				}
			}

			// get 20 decimal digits, put sign back, add new exponent
			//UPGRADE_TODO: The equivalent in .NET for Class C#.math.BigDecimal.ROUND_HALF_EVEN will be considered in a future release.;
			//val = val.setScale(20, BigDecimal.ROUND_HALF_EVEN);
			//UPGRADE_TODO: The equivalent in .NET for Class C#.math.BigDecimal.toString will be considered in a future release.;
			str = (sign == 1?"-":"") + System.Convert.ToString(val) + "e" + System.Convert.ToString(exp);

			// write the value
			this.write1(OtpExternal.floatTag);
			//UPGRADE_NOTE: This code will be optimized in the future;
			byte[] tmpBytes;
			int i;
			string tmpStr;
			tmpStr = str;
			tmpBytes = new byte[tmpStr.Length];
			i = 0;
			while (i < tmpStr.Length)
			{
				tmpBytes[i] = (byte) tmpStr[i];
				i++;
			}
			this.writeN(tmpBytes);
			
			// pad with zeros to 31 bytes
			//UPGRADE_NOTE: This code will be optimized in the future;
			byte[] tmpBytes2;
			int i2;
			string tmpStr2;
			tmpStr2 = str;
			tmpBytes2 = new byte[tmpStr2.Length];
			i2 = 0;
			while (i2 < tmpStr2.Length)
			{
				tmpBytes2[i2] = (byte) tmpStr2[i2];
				i2++;
			}
			int i3 = (int) (tmpBytes2.Length);
			 for (; i3 < 31; i3++)
				this.write1(0);
		}
		
		
		/*
		* Write a float value to the stream. 
		*
		* @param f the float to use.
		**/
		public virtual void  write_float(float f)
		{
			this.write_double(f);
		}
		
		/*
		* Write a long to the stream.
		*
		* @param l the long to use.
		**/
		public virtual void  write_long(long l)
		{
			if ((l & 0xff) == l)
			{
				// will fit in one byte
				this.write1(OtpExternal.smallIntTag);
				this.write1(l);
			}
			else if ((l <= OtpExternal.erlMax) && (l >= OtpExternal.erlMin))
			{
				this.write1(OtpExternal.intTag);
				this.write4BE(l);
			}
			else
			{
				this.write1(OtpExternal.smallBigTag);
				this.write1(4); // length
				
				// obs! little endian here
				if (l < 0)
				{
					this.write1(1); // sign
					this.write4LE(- l); // value
				}
				else
				{
					this.write1(0); // sign
					this.write4LE(l); //value
				}
			}
		}
		
		/*
		* Write a positive long to the stream.
		*
		* @param ul the long to use.
		**/
		public virtual void  write_ulong(long ul)
		{
			this.write_long(ul);
		}
		
		/*
		* Write an integer to the stream.
		*
		* @param i the integer to use.
		**/
		public virtual void  write_int(int i)
		{
			this.write_long(i);
		}
		
		/*
		* Write a positive integer to the stream.
		*
		* @param ui the integer to use.
		**/
		public virtual void  write_uint(int ui)
		{
			this.write_long(ui);
		}
		
		/*
		* Write a short to the stream.
		*
		* @param s the short to use.
		**/
		public virtual void  write_short(short s)
		{
			this.write_long(s);
		}
		
		/*
		* Write a positive short to the stream.
		*
		* @param s the short to use.
		**/
		public virtual void  write_ushort(short us)
		{
			this.write_long(us);
		}
		
		/*
		* Write an Erlang list header to the stream. After calling this
		* method, you must write 'arity' elements to the stream followed by
		* nil, or it will not be possible to decode it later.
		*
		* @param arity the number of elements in the list.
		**/
		public virtual void  write_list_head(int arity)
		{
			if (arity == 0)
			{
				this.write_nil();
			}
			else
			{
				this.write1(OtpExternal.listTag);
				this.write4BE(arity);
			}
		}
		
		/*
		* Write an empty Erlang list to the stream.
		**/
		public virtual void  write_nil()
		{
			this.write1(OtpExternal.nilTag);
		}
		
		/*
		* Write an Erlang tuple header to the stream. After calling this
		* method, you must write 'arity' elements to the stream or it will
		* not be possible to decode it later.
		*
		* @param arity the number of elements in the tuple.
		**/
		public virtual void  write_tuple_head(int arity)
		{
			if (arity < 0xff)
			{
				this.write1(OtpExternal.smallTupleTag);
				this.write1(arity);
			}
			else
			{
				this.write1(OtpExternal.largeTupleTag);
				this.write4BE(arity);
			}
		}
		
		/*
		* Write an Erlang PID to the stream. 
		*
		* @param node the nodename.
		*
		* @param id an arbitrary number. Only the low order 15 bits will
		* be used.
		*
		* @param serial another arbitrary number. Only the low order 3 bits
		* will be used.
		*
		* @param creation yet another arbitrary number. Only the low order
		* 2 bits will be used.
		* 
		**/
		public virtual void  write_pid(System.String node, int id, int serial, int creation)
		{
			this.write1(OtpExternal.pidTag);
			this.write_atom(node);
			this.write4BE(id & 0x7fff); // 15 bits
			this.write4BE(serial & 0x7); // 3 bits
			this.write1(creation & 0x3); // 2 bits
		}
		
		/*
		* Write an Erlang port to the stream. 
		*
		* @param node the nodename.
		*
		* @param id an arbitrary number. Only the low order 18 bits will
		* be used.
		*
		* @param creation another arbitrary number. Only the low order 2
		* bits will be used.
		* 
		**/
		public virtual void  write_port(System.String node, int id, int creation)
		{
			this.write1(OtpExternal.portTag);
			this.write_atom(node);
			this.write4BE(id & 0x3ffff); // 18 bits
			this.write1(creation & 0x3); // 2 bits
		}
		
		/*
		* Write an old style Erlang ref to the stream. 
		*
		* @param node the nodename.
		*
		* @param id an arbitrary number. Only the low order 18 bits will
		* be used.
		*
		* @param creation another arbitrary number. Only the low order 2
		* bits will be used.
		* 
		**/
		public virtual void  write_ref(System.String node, int id, int creation)
		{
			this.write1(OtpExternal.refTag);
			this.write_atom(node);
			this.write4BE(id & 0x3ffff); // 18 bits
			this.write1(creation & 0x3); // 2 bits
		}
		
		/*
		* Write a new style (R6 and later) Erlang ref to the stream.
		*
		* @param node the nodename.
		*
		* @param ids an array of arbitrary numbers. Only the low order 18
		* bits of the first number will be used. If the array contains only
		* one number, an old style ref will be written instead. At most
		* three numbers will be read from the array.
		*
		* @param creation another arbitrary number. Only the low order
		* 2 bits will be used.
		* 
		**/
		public virtual void  write_ref(System.String node, int[] ids, int creation)
		{
			int arity = (int) (ids.Length);
			if (arity > 3)
				arity = 3;
			// max 3 words in ref
			
			if (arity == 1)
			{
				// use old method
				this.write_ref(node, ids[0], creation);
			}
			else
			{
				// r6 ref
				this.write1(OtpExternal.newRefTag);
				
				// how many id values
				this.write2BE(arity);
				
				this.write_atom(node);
				
				// note: creation BEFORE id in r6 ref
				this.write1(creation & 0x3); // 2 bits
				
				// first int gets truncated to 18 bits
				this.write4BE(ids[0] & 0x3ffff);
				
				// remaining ones are left as is
				 for (int i = 1; i < arity; i++)
					this.write4BE(ids[i]);
			}
		}
		
		/*
		* Write a string to the stream.
		*
		* @param s the string to write.
		**/
		public virtual void  write_string(System.String s)
		{
			int len = s.Length;
			
			switch (len)
			{
				case 0: 
					this.write_nil();
					break;
				
				default: 
					//UPGRADE_NOTE: This code will be optimized in the future;
					byte[] tmpBytes;
					int i;
					string tmpStr;
					tmpStr = s;
					tmpBytes = new byte[tmpStr.Length];
					i = 0;
					while (i < tmpStr.Length)
					{
						tmpBytes[i] = (byte) tmpStr[i];
						i++;
					}
					byte[] bytebuf = tmpBytes;
					
					/*switch to se if the length of
					the byte array is equal to the 
					length of the list */
					if (bytebuf.Length == len)
					{
						/*Usual */
						this.write1(OtpExternal.stringTag);
						this.write2BE(len);
						this.writeN(bytebuf);
					}
					else
					{
						/*Unicode */
						char[] charbuf = s.ToCharArray();
						
						this.write_list_head(len);
						
						 for (int i2 = 0; i2 < len; i2++)
							this.write_char(charbuf[i2]);
						
						this.write_nil();
					}
					break;
				
			}
		}
		
		
		/*
		This does not work when char > 1 byte Unicode is used
		
		public void write_string(String s) {
		this.write1(OtpExternal.stringTag);
		this.write2BE(s.length());
		this.writeN(s.getBytes());
		}*/
		
		/*
		* Write an arbitrary Erlang term to the stream.
		*
		* @param o the Erlang term to write.
		*/
		public virtual void write_any(Erlang.Object o)
		{
			// calls one of the above functions, depending on o
			o.encode(this);
		}
	}
}