BinaryWriter.cs source code in C# .NET

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Code:

                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / clr / src / BCL / System / IO / BinaryWriter.cs / 1 / BinaryWriter.cs
                        

                        
                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 
/*============================================================
** 
** Class:  BinaryWriter 
**
** Purpose: Provides a way to write primitives types in 
** binary from a Stream, while also supporting writing Strings
** in a particular encoding.
**
** 
===========================================================*/
using System; 
using System.Text; 

namespace System.IO { 
    // This abstract base class represents a writer that can write
    // primitives to an arbitrary stream. A subclass can override methods to
    // give unique encodings.
    // 
    [Serializable]
[System.Runtime.InteropServices.ComVisible(true)] 
    public class BinaryWriter : IDisposable 
    {
        public static readonly BinaryWriter Null = new BinaryWriter(); 

        protected Stream OutStream;
        private byte[] _buffer;    // temp space for writing primitives to.
        private Encoding _encoding; 
        private Encoder _encoder;
        private char[] _tmpOneCharBuffer = new char[1]; 
 
        // Perf optimization stuff
        private byte[] _largeByteBuffer;  // temp space for writing chars. 
        private int _maxChars;   // max # of chars we can put in _largeByteBuffer
        // Size should be around the max number of chars/string * Encoding's max bytes/char
        private const int LargeByteBufferSize = 256;
 
        // Protected default constructor that sets the output stream
        // to a null stream (a bit bucket). 
        protected BinaryWriter() 
        {
            OutStream = Stream.Null; 
            _buffer = new byte[16];
            _encoding = new UTF8Encoding(false, true);
            _encoder = _encoding.GetEncoder();
        } 

        public BinaryWriter(Stream output) : this(output, new UTF8Encoding(false, true)) 
        { 
        }
 
        public BinaryWriter(Stream output, Encoding encoding)
        {
            if (output==null)
                throw new ArgumentNullException("output"); 
            if (encoding==null)
                throw new ArgumentNullException("encoding"); 
            if (!output.CanWrite) 
                throw new ArgumentException(Environment.GetResourceString("Argument_StreamNotWritable"));
 
            OutStream = output;
            _buffer = new byte[16];
            _encoding = encoding;
            _encoder = _encoding.GetEncoder(); 
        }
 
        // Closes this writer and releases any system resources associated with the 
        // writer. Following a call to Close, any operations on the writer
        // may raise exceptions. 
        public virtual void Close()
        {
            Dispose(true);
        } 

        protected virtual void Dispose(bool disposing) 
        { 
            if (disposing)
                OutStream.Close(); 
        }

        /// 
        void IDisposable.Dispose() 
        {
            Dispose(true); 
        } 

        /* 
         * Returns the stream associate with the writer. It flushes all pending
         * writes before returning. All subclasses should override Flush to
         * ensure that all buffered data is sent to the stream.
         */ 
        public virtual Stream BaseStream {
            get { 
                Flush(); 
                return OutStream;
            } 
        }

        // Clears all buffers for this writer and causes any buffered data to be
        // written to the underlying device. 
        public virtual void Flush()
        { 
            OutStream.Flush(); 
        }
 
        public virtual long Seek(int offset, SeekOrigin origin)
        {
            return OutStream.Seek(offset, origin);
        } 

        // Writes a boolean to this stream. A single byte is written to the stream 
        // with the value 0 representing false or the value 1 representing true. 
        //
        public virtual void Write(bool value) { 
            _buffer[0] = (byte) (value ? 1 : 0);
            OutStream.Write(_buffer, 0, 1);
        }
 
        // Writes a byte to this stream. The current position of the stream is
        // advanced by one. 
        // 
        public virtual void Write(byte value)
        { 
            OutStream.WriteByte(value);
        }

        // Writes a signed byte to this stream. The current position of the stream 
        // is advanced by one.
        // 
        [CLSCompliant(false)] 
        public virtual void Write(sbyte value)
        { 
            OutStream.WriteByte((byte) value);
        }

        // Writes a byte array to this stream. 
        //
        // This default implementation calls the Write(Object, int, int) 
        // method to write the byte array. 
        //
        public virtual void Write(byte[] buffer) { 
            if (buffer == null)
                throw new ArgumentNullException("buffer");
            OutStream.Write(buffer, 0, buffer.Length);
        } 

        // Writes a section of a byte array to this stream. 
        // 
        // This default implementation calls the Write(Object, int, int)
        // method to write the byte array. 
        //
        public virtual void Write(byte[] buffer, int index, int count) {
            OutStream.Write(buffer, index, count);
        } 

 
        // Writes a character to this stream. The current position of the stream is 
        // advanced by two.
        // Note this method cannot handle surrogates properly in UTF-8. 
        //
        public unsafe virtual void Write(char ch) {
            if (Char.IsSurrogate(ch))
                throw new ArgumentException(Environment.GetResourceString("Arg_SurrogatesNotAllowedAsSingleChar")); 

            BCLDebug.Assert(_encoding.GetMaxByteCount(1) <= 16, "_encoding.GetMaxByteCount(1) <= 16)"); 
            int numBytes = 0; 
            fixed(byte * pBytes = _buffer) {
                numBytes = _encoder.GetBytes(&ch, 1, pBytes, 16, true); 
            }
            OutStream.Write(_buffer, 0, numBytes);
        }
 
        // Writes a character array to this stream.
        // 
        // This default implementation calls the Write(Object, int, int) 
        // method to write the character array.
        // 
        public virtual void Write(char[] chars)
        {
            if (chars == null)
                throw new ArgumentNullException("chars"); 

            byte[] bytes = _encoding.GetBytes(chars, 0, chars.Length); 
            OutStream.Write(bytes, 0, bytes.Length); 
        }
 
        // Writes a section of a character array to this stream.
        //
        // This default implementation calls the Write(Object, int, int)
        // method to write the character array. 
        //
        public virtual void Write(char[] chars, int index, int count) 
        { 
            byte[] bytes = _encoding.GetBytes(chars, index, count);
            OutStream.Write(bytes, 0, bytes.Length); 
        }


        // Writes a double to this stream. The current position of the stream is 
        // advanced by eight.
        // 
        public unsafe virtual void Write(double value) 
        {
            ulong TmpValue = *(ulong *)&value; 
            _buffer[0] = (byte) TmpValue;
            _buffer[1] = (byte) (TmpValue >> 8);
            _buffer[2] = (byte) (TmpValue >> 16);
            _buffer[3] = (byte) (TmpValue >> 24); 
            _buffer[4] = (byte) (TmpValue >> 32);
            _buffer[5] = (byte) (TmpValue >> 40); 
            _buffer[6] = (byte) (TmpValue >> 48); 
            _buffer[7] = (byte) (TmpValue >> 56);
            OutStream.Write(_buffer, 0, 8); 
        }

        public virtual void Write(decimal value)
        { 
            Decimal.GetBytes(value,_buffer);
            OutStream.Write(_buffer, 0, 16); 
        } 

        // Writes a two-byte signed integer to this stream. The current position of 
        // the stream is advanced by two.
        //
        public virtual void Write(short value)
        { 
            _buffer[0] = (byte) value;
            _buffer[1] = (byte) (value >> 8); 
            OutStream.Write(_buffer, 0, 2); 
        }
 
        // Writes a two-byte unsigned integer to this stream. The current position
        // of the stream is advanced by two.
        //
        [CLSCompliant(false)] 
        public virtual void Write(ushort value)
        { 
            _buffer[0] = (byte) value; 
            _buffer[1] = (byte) (value >> 8);
            OutStream.Write(_buffer, 0, 2); 
        }

        // Writes a four-byte signed integer to this stream. The current position
        // of the stream is advanced by four. 
        //
        public virtual void Write(int value) 
        { 
            _buffer[0] = (byte) value;
            _buffer[1] = (byte) (value >> 8); 
            _buffer[2] = (byte) (value >> 16);
            _buffer[3] = (byte) (value >> 24);
            OutStream.Write(_buffer, 0, 4);
        } 

        // Writes a four-byte unsigned integer to this stream. The current position 
        // of the stream is advanced by four. 
        //
        [CLSCompliant(false)] 
        public virtual void Write(uint value)
        {
            _buffer[0] = (byte) value;
            _buffer[1] = (byte) (value >> 8); 
            _buffer[2] = (byte) (value >> 16);
            _buffer[3] = (byte) (value >> 24); 
            OutStream.Write(_buffer, 0, 4); 
        }
 
        // Writes an eight-byte signed integer to this stream. The current position
        // of the stream is advanced by eight.
        //
        public virtual void Write(long value) 
        {
            _buffer[0] = (byte) value; 
            _buffer[1] = (byte) (value >> 8); 
            _buffer[2] = (byte) (value >> 16);
            _buffer[3] = (byte) (value >> 24); 
            _buffer[4] = (byte) (value >> 32);
            _buffer[5] = (byte) (value >> 40);
            _buffer[6] = (byte) (value >> 48);
            _buffer[7] = (byte) (value >> 56); 
            OutStream.Write(_buffer, 0, 8);
        } 
 
        // Writes an eight-byte unsigned integer to this stream. The current
        // position of the stream is advanced by eight. 
        //
        [CLSCompliant(false)]
        public virtual void Write(ulong value)
        { 
            _buffer[0] = (byte) value;
            _buffer[1] = (byte) (value >> 8); 
            _buffer[2] = (byte) (value >> 16); 
            _buffer[3] = (byte) (value >> 24);
            _buffer[4] = (byte) (value >> 32); 
            _buffer[5] = (byte) (value >> 40);
            _buffer[6] = (byte) (value >> 48);
            _buffer[7] = (byte) (value >> 56);
            OutStream.Write(_buffer, 0, 8); 
        }
 
        // Writes a float to this stream. The current position of the stream is 
        // advanced by four.
        // 
        public unsafe virtual void Write(float value)
        {
            uint TmpValue = *(uint *)&value;
            _buffer[0] = (byte) TmpValue; 
            _buffer[1] = (byte) (TmpValue >> 8);
            _buffer[2] = (byte) (TmpValue >> 16); 
            _buffer[3] = (byte) (TmpValue >> 24); 
            OutStream.Write(_buffer, 0, 4);
        } 


        // Writes a length-prefixed string to this stream in the BinaryWriter's
        // current Encoding. This method first writes the length of the string as 
        // a four-byte unsigned integer, and then writes that many characters
        // to the stream. 
        // 
        public unsafe virtual void Write(String value)
        { 
            if (value==null)
                throw new ArgumentNullException("value");

            int len = _encoding.GetByteCount(value); 
            Write7BitEncodedInt(len);
 
            if (_largeByteBuffer == null) { 
                _largeByteBuffer = new byte[LargeByteBufferSize];
                _maxChars = LargeByteBufferSize / _encoding.GetMaxByteCount(1); 
            }

            if (len <= LargeByteBufferSize) {
                //BCLDebug.Assert(len == _encoding.GetBytes(chars, 0, chars.Length, _largeByteBuffer, 0), "encoding's GetByteCount & GetBytes gave different answers!  encoding type: "+_encoding.GetType().Name); 
                _encoding.GetBytes(value, 0, value.Length, _largeByteBuffer, 0);
                OutStream.Write(_largeByteBuffer, 0, len); 
            } 
            else {
                // Aggressively try to not allocate memory in this loop for 
                // runtime performance reasons.  Use an Encoder to write out
                // the string correctly (handling surrogates crossing buffer
                // boundaries properly).
                int charStart = 0; 
                int numLeft = value.Length;
#if _DEBUG 
                int totalBytes = 0; 
#endif
                while (numLeft > 0) { 
                    // Figure out how many chars to process this round.
                    int charCount = (numLeft > _maxChars) ? _maxChars : numLeft;
                    int byteLen;
                    fixed(char* pChars = value) { 
                        fixed(byte* pBytes = _largeByteBuffer) {
                            byteLen = _encoder.GetBytes(pChars + charStart, charCount, pBytes, LargeByteBufferSize, charCount == numLeft); 
                        } 
                    }
#if _DEBUG 
                    totalBytes += byteLen;
                    BCLDebug.Assert (totalBytes <= len && byteLen <= LargeByteBufferSize, "BinaryWriter::Write(String) - More bytes encoded than expected!");
#endif
                    OutStream.Write(_largeByteBuffer, 0, byteLen); 
                    charStart += charCount;
                    numLeft -= charCount; 
                } 
#if _DEBUG
                BCLDebug.Assert(totalBytes == len, "BinaryWriter::Write(String) - Didn't write out all the bytes!"); 
#endif
            }
        }
 
        protected void Write7BitEncodedInt(int value) {
            // Write out an int 7 bits at a time.  The high bit of the byte, 
            // when on, tells reader to continue reading more bytes. 
            uint v = (uint) value;   // support negative numbers
            while (v >= 0x80) { 
                Write((byte) (v | 0x80));
                v >>= 7;
            }
            Write((byte)v); 
        }
    } 
}

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