BinaryReader.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / clr / src / BCL / System / IO / BinaryReader.cs / 1 / BinaryReader.cs
                        

                        
                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 
/*============================================================
** 
** Class: BinaryReader 
**
** 
** Purpose: Wraps a stream and provides convenient read functionality
** for strings and primitive types.
**
** 
============================================================*/
namespace System.IO { 
 
    using System;
    using System.Text; 
    using System.Globalization;

[System.Runtime.InteropServices.ComVisible(true)]
    public class BinaryReader : IDisposable 
    {
        private const int MaxCharBytesSize = 128; 
 
        private Stream   m_stream;
        private byte[]   m_buffer; 
        private Decoder  m_decoder;
        private byte[]   m_charBytes;
        private char[]   m_singleChar;
        private char[]   m_charBuffer; 
        private int      m_maxCharsSize;  // From MaxCharBytesSize & Encoding
 
        // Performance optimization for Read() w/ Unicode.  Speeds us up by ~40% 
        private bool     m_2BytesPerChar;
        private bool     m_isMemoryStream; // "do we sit on MemoryStream?" for Read/ReadInt32 perf 

        public BinaryReader(Stream input) : this(input, new UTF8Encoding()) {
        }
 
        public BinaryReader(Stream input, Encoding encoding) {
            if (input==null) { 
                throw new ArgumentNullException("input"); 
            }
            if (encoding==null) { 
                throw new ArgumentNullException("encoding");
            }
            if (!input.CanRead)
                throw new ArgumentException(Environment.GetResourceString("Argument_StreamNotReadable")); 
            m_stream = input;
            m_decoder = encoding.GetDecoder(); 
            m_maxCharsSize = encoding.GetMaxCharCount(MaxCharBytesSize); 
            int minBufferSize = encoding.GetMaxByteCount(1);  // max bytes per one char
            if (minBufferSize < 16) 
                minBufferSize = 16;
            m_buffer = new byte[minBufferSize];
            m_charBuffer = null;
            m_charBytes  = null; 

            // For Encodings that always use 2 bytes per char (or more), 
            // special case them here to make Read() & Peek() faster. 
            m_2BytesPerChar = encoding is UnicodeEncoding;
            // check if BinaryReader is based on MemoryStream, and keep this for it's life 
            // we cannot use "as" operator, since derived classes are not allowed
            m_isMemoryStream = (m_stream.GetType() == typeof(MemoryStream));

            BCLDebug.Assert(m_decoder!=null, "[BinaryReader.ctor]m_decoder!=null"); 
        }
 
        public virtual Stream BaseStream { 
            get {
                return m_stream; 
            }
        }

        public virtual void Close() { 
            Dispose(true);
        } 
 
        protected virtual void Dispose(bool disposing) {
            if (disposing) { 
                Stream copyOfStream = m_stream;
                m_stream = null;
                if (copyOfStream != null)
                    copyOfStream.Close(); 
            }
            m_stream = null; 
            m_buffer = null; 
            m_decoder = null;
            m_charBytes = null; 
            m_singleChar = null;
            m_charBuffer = null;
        }
 
        /// 
        void IDisposable.Dispose() 
        { 
            Dispose(true);
        } 

        public virtual int PeekChar() {
            if (m_stream==null) __Error.FileNotOpen();
 
            if (!m_stream.CanSeek)
                return -1; 
            long origPos = m_stream.Position; 
            int ch = Read();
            m_stream.Position = origPos; 
            return ch;
        }

        public virtual int Read() { 
            if (m_stream==null) {
                __Error.FileNotOpen(); 
            } 
            return InternalReadOneChar();
        } 

        public virtual bool ReadBoolean(){
            FillBuffer(1);
            return (m_buffer[0]!=0); 
        }
 
        public virtual byte ReadByte() { 
            // Inlined to avoid some method call overhead with FillBuffer.
            if (m_stream==null) __Error.FileNotOpen(); 

            int b = m_stream.ReadByte();
            if (b == -1)
                __Error.EndOfFile(); 
            return (byte) b;
        } 
 
        [CLSCompliant(false)]
        public virtual sbyte ReadSByte() { 
            FillBuffer(1);
            return (sbyte)(m_buffer[0]);
        }
 
        public virtual char ReadChar() {
            int value = Read(); 
            if (value==-1) { 
                __Error.EndOfFile();
            } 
            return (char)value;
        }

        public virtual short ReadInt16() { 
            FillBuffer(2);
            return (short)(m_buffer[0] | m_buffer[1] << 8); 
        } 

        [CLSCompliant(false)] 
        public virtual ushort ReadUInt16(){
            FillBuffer(2);
            return (ushort)(m_buffer[0] | m_buffer[1] << 8);
        } 

        public virtual int ReadInt32() { 
            if (m_isMemoryStream) { 
                // read directly from MemoryStream buffer
                MemoryStream mStream = m_stream as MemoryStream; 
                BCLDebug.Assert(mStream != null, "m_stream as MemoryStream != null");

                return mStream.InternalReadInt32();
            } 
            else
            { 
                FillBuffer(4); 
                return (int)(m_buffer[0] | m_buffer[1] << 8 | m_buffer[2] << 16 | m_buffer[3] << 24);
            } 
        }

        [CLSCompliant(false)]
        public virtual uint ReadUInt32() { 
            FillBuffer(4);
            return (uint)(m_buffer[0] | m_buffer[1] << 8 | m_buffer[2] << 16 | m_buffer[3] << 24); 
        } 

        public virtual long ReadInt64() { 
            FillBuffer(8);
            uint lo = (uint)(m_buffer[0] | m_buffer[1] << 8 |
                             m_buffer[2] << 16 | m_buffer[3] << 24);
            uint hi = (uint)(m_buffer[4] | m_buffer[5] << 8 | 
                             m_buffer[6] << 16 | m_buffer[7] << 24);
            return (long) ((ulong)hi) << 32 | lo; 
        } 

        [CLSCompliant(false)] 
        public virtual ulong ReadUInt64() {
            FillBuffer(8);
            uint lo = (uint)(m_buffer[0] | m_buffer[1] << 8 |
                             m_buffer[2] << 16 | m_buffer[3] << 24); 
            uint hi = (uint)(m_buffer[4] | m_buffer[5] << 8 |
                             m_buffer[6] << 16 | m_buffer[7] << 24); 
            return ((ulong)hi) << 32 | lo; 
        }
 
        public virtual unsafe float ReadSingle() {
            FillBuffer(4);
            uint tmpBuffer = (uint)(m_buffer[0] | m_buffer[1] << 8 | m_buffer[2] << 16 | m_buffer[3] << 24);
            return *((float*)&tmpBuffer); 
        }
 
        public virtual unsafe double ReadDouble() { 
            FillBuffer(8);
            uint lo = (uint)(m_buffer[0] | m_buffer[1] << 8 | 
                m_buffer[2] << 16 | m_buffer[3] << 24);
            uint hi = (uint)(m_buffer[4] | m_buffer[5] << 8 |
                m_buffer[6] << 16 | m_buffer[7] << 24);
 
            ulong tmpBuffer = ((ulong)hi) << 32 | lo;
            return *((double*)&tmpBuffer); 
        } 

        public virtual decimal ReadDecimal() { 
            FillBuffer(16);
            return Decimal.ToDecimal(m_buffer);
        }
 
        public virtual String ReadString() {
            int currPos = 0; 
            int n; 
            int stringLength;
            int readLength; 
            int charsRead;

            if (m_stream==null)
                __Error.FileNotOpen(); 

            // Length of the string in bytes, not chars 
            stringLength = Read7BitEncodedInt(); 
            if (stringLength<0) {
                throw new IOException(String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("IO.IO_InvalidStringLen_Len"), stringLength)); 
            }

            if (stringLength==0) {
                return String.Empty; 
            }
 
            if (m_charBytes==null) { 
                m_charBytes  = new byte[MaxCharBytesSize];
            } 

            if (m_charBuffer == null) {
                m_charBuffer = new char[m_maxCharsSize];
            } 

            StringBuilder sb = null; 
            do 
            {
                readLength = ((stringLength - currPos)>MaxCharBytesSize)?MaxCharBytesSize:(stringLength - currPos); 

                n = m_stream.Read(m_charBytes, 0, readLength);
                if (n==0) {
                    __Error.EndOfFile(); 
                }
 
                charsRead = m_decoder.GetChars(m_charBytes, 0, n, m_charBuffer, 0); 

                if (currPos == 0 && n == stringLength) 
                    return new String(m_charBuffer, 0, charsRead);

                if (sb == null)
                    sb = new StringBuilder(stringLength); // Actual string length in chars may be smaller. 
                sb.Append(m_charBuffer, 0, charsRead);
                currPos +=n; 
 
            } while (currPos0) { 
                // We really want to know what the minimum number of bytes per char 
                // is for our encoding.  Otherwise for UnicodeEncoding we'd have to
                // do ~1+log(n) reads to read n characters. 
                numBytes = charsRemaining;
                if (m_2BytesPerChar)
                    numBytes <<= 1;
                if (numBytes > MaxCharBytesSize) 
                    numBytes = MaxCharBytesSize;
 
                if (m_isMemoryStream) 
                {
                    MemoryStream mStream = m_stream as MemoryStream; 
                    BCLDebug.Assert(mStream != null, "m_stream as MemoryStream != null");

                    int position = mStream.InternalGetPosition();
                    numBytes = mStream.InternalEmulateRead(numBytes); 
                    if (numBytes == 0) {
                        return (count - charsRemaining); 
                    } 
                    charsRead = m_decoder.GetChars(mStream.InternalGetBuffer(), position, numBytes, buffer, index);
                } 
                else
                {
                    numBytes = m_stream.Read(m_charBytes, 0, numBytes);
                    if (numBytes==0) { 
                        //  Console.WriteLine("Found no bytes.  We're outta here.");
                        return (count - charsRemaining); 
                    } 
                    charsRead = m_decoder.GetChars(m_charBytes, 0, numBytes, buffer, index);
                } 

                charsRemaining -= charsRead;
                index+=charsRead;
                //                Console.WriteLine("That became: " + charsRead + " characters."); 
            }
            BCLDebug.Assert(charsRemaining == 0, "We didn't read all the chars we thought we would."); 
            return count; 
        }
 
        private int InternalReadOneChar() {
            // I know having a separate InternalReadOneChar method seems a little
            // redundant, but this makes a scenario like the security parser code
            // 20% faster, in addition to the optimizations for UnicodeEncoding I 
            // put in InternalReadChars.
            int charsRead = 0; 
            int numBytes = 0; 
            long posSav = posSav = 0;
 
            if (m_stream.CanSeek)
                posSav = m_stream.Position;

            if (m_charBytes==null) { 
                m_charBytes = new byte[MaxCharBytesSize]; //
            } 
            if (m_singleChar==null) { 
                m_singleChar = new char[1];
            } 

            while (charsRead == 0) {
                // We really want to know what the minimum number of bytes per char
                // is for our encoding.  Otherwise for UnicodeEncoding we'd have to 
                // do ~1+log(n) reads to read n characters.
                // Assume 1 byte can be 1 char unless m_2BytesPerChar is true. 
                numBytes = m_2BytesPerChar ? 2 : 1; 

                int r = m_stream.ReadByte(); 
                m_charBytes[0] = (byte) r;
                if (r == -1)
                    numBytes = 0;
                if (numBytes == 2) { 
                    r = m_stream.ReadByte();
                    m_charBytes[1] = (byte) r; 
                    if (r == -1) 
                        numBytes = 1;
                } 

                if (numBytes==0) {
                    // Console.WriteLine("Found no bytes.  We're outta here.");
                    return -1; 
                }
 
                BCLDebug.Assert(numBytes == 1 || numBytes == 2, "BinaryReader::InternalReadOneChar assumes it's reading one or 2 bytes only."); 

                try { 

                    charsRead = m_decoder.GetChars(m_charBytes, 0, numBytes, m_singleChar, 0);
                }
                catch 
                {
                    // Handle surrogate char 
 
                    if (m_stream.CanSeek)
                        m_stream.Seek((posSav - m_stream.Position), SeekOrigin.Current); 
                    // else - we can't do much here

                    throw;
                } 

                BCLDebug.Assert(charsRead < 2, "InternalReadOneChar - assuming we only got 0 or 1 char, not 2!"); 
                //                Console.WriteLine("That became: " + charsRead + " characters."); 
            }
            if (charsRead == 0) 
                return -1;
            return m_singleChar[0];
        }
 
        public virtual char[] ReadChars(int count) {
            if (m_stream==null) { 
                __Error.FileNotOpen(); 
            }
            if (count<0) { 
                throw new ArgumentOutOfRangeException("count", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
            }
            char[] chars = new char[count];
            int n = InternalReadChars(chars, 0, count); 
            if (n!=count) {
                char[] copy = new char[n]; 
                Buffer.InternalBlockCopy(chars, 0, copy, 0, 2*n); // sizeof(char) 
                chars = copy;
            } 

            return chars;
        }
 
        public virtual int Read(byte[] buffer, int index, int count) {
            if (buffer==null) 
                throw new ArgumentNullException("buffer", Environment.GetResourceString("ArgumentNull_Buffer")); 
            if (index < 0)
                throw new ArgumentOutOfRangeException("index", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum")); 
            if (count < 0)
                throw new ArgumentOutOfRangeException("count", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
            if (buffer.Length - index < count)
                throw new ArgumentException(Environment.GetResourceString("Argument_InvalidOffLen")); 

            if (m_stream==null) __Error.FileNotOpen(); 
            return m_stream.Read(buffer, index, count); 
        }
 
        public virtual byte[] ReadBytes(int count) {
            if (count < 0) throw new ArgumentOutOfRangeException("count", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
            if (m_stream==null) __Error.FileNotOpen();
 
            byte[] result = new byte[count];
 
            int numRead = 0; 
            do {
                int n = m_stream.Read(result, numRead, count); 
                if (n == 0)
                    break;
                numRead += n;
                count -= n; 
            } while (count > 0);
 
            if (numRead != result.Length) { 
                // Trim array.  This should happen on EOF & possibly net streams.
                byte[] copy = new byte[numRead]; 
                Buffer.InternalBlockCopy(result, 0, copy, 0, numRead);
                result = copy;
            }
 
            return result;
        } 
 
        protected virtual void FillBuffer(int numBytes) {
            BCLDebug.Assert(m_buffer==null || (numBytes>0 && numBytes<=m_buffer.Length), "[FillBuffer]numBytes>0 && numBytes<=m_buffer.Length"); 
            int bytesRead=0;
            int n = 0;

            if (m_stream==null) __Error.FileNotOpen(); 

            // Need to find a good threshold for calling ReadByte() repeatedly 
            // vs. calling Read(byte[], int, int) for both buffered & unbuffered 
            // streams.
            if (numBytes==1) { 
                n = m_stream.ReadByte();
                if (n==-1)
                    __Error.EndOfFile();
                m_buffer[0] = (byte)n; 
                return;
            } 
 
            do {
                n = m_stream.Read(m_buffer, bytesRead, numBytes-bytesRead); 
                if (n==0) {
                    __Error.EndOfFile();
                }
                bytesRead+=n; 
            } while (bytesRead

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