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[ASP.net教程]c#,关于Big Endian 和 Little Endian,以及转换类


Big Endian:最高字节在地址最低位,最低字节在地址最高位,依次排列。 
Little Endian:最低字节在最低位,最高字节在最高位,反序排列。

当在本地主机上,无需注意机器用的是Big Endian还是Little Endian。但是网络上都是用的是Big Endian,需要进行一个转换,但是c#提供的BitConverter默认使用的Little Endian,在需与网络通信时,反的字节序大有不便,特此提供一个可选Big Endian和Little Endian类方便转换。

为什么存在Little Endian?因为对于机器来说,Little Endian更有利于机器的运算。内存地址由低位到高位,在两个数相加运算,直接在高位添加进位数,不必移动内存地址

 

第一部分

using System;using System.Runtime.InteropServices;namespace MiscUtil.Conversion{  /// <summary>  /// Equivalent of System.BitConverter, but with either endianness.  /// </summary>  public abstract class EndianBitConverter  {    #region Endianness of this converter    /// <summary>    /// Indicates the byte order ("endianess") in which data is converted using this class.    /// </summary>    /// <remarks>    /// Different computer architectures store data using different byte orders. "Big-endian"    /// means the most significant byte is on the left end of a word. "Little-endian" means the    /// most significant byte is on the right end of a word.    /// </remarks>    /// <returns>true if this converter is little-endian, false otherwise.</returns>    public abstract bool IsLittleEndian();    /// <summary>    /// Indicates the byte order ("endianess") in which data is converted using this class.    /// </summary>    public abstract Endianness Endianness { get; }    #endregion    #region Factory properties    static LittleEndianBitConverter little = new LittleEndianBitConverter();    /// <summary>    /// Returns a little-endian bit converter instance. The same instance is    /// always returned.    /// </summary>    public static LittleEndianBitConverter Little    {      get { return little; }    }    static BigEndianBitConverter big = new BigEndianBitConverter();    /// <summary>    /// Returns a big-endian bit converter instance. The same instance is    /// always returned.    /// </summary>    public static BigEndianBitConverter Big    {      get { return big; }    }    #endregion    #region Double/primitive conversions    /// <summary>    /// Converts the specified double-precision floating point number to a    /// 64-bit signed integer. Note: the endianness of this converter does not    /// affect the returned value.    /// </summary>    /// <param name="value">The number to convert. </param>    /// <returns>A 64-bit signed integer whose value is equivalent to value.</returns>    public long DoubleToInt64Bits(double value)    {      return BitConverter.DoubleToInt64Bits(value);    }    /// <summary>    /// Converts the specified 64-bit signed integer to a double-precision    /// floating point number. Note: the endianness of this converter does not    /// affect the returned value.    /// </summary>    /// <param name="value">The number to convert. </param>    /// <returns>A double-precision floating point number whose value is equivalent to value.</returns>    public double Int64BitsToDouble (long value)    {      return BitConverter.Int64BitsToDouble(value);    }    /// <summary>    /// Converts the specified single-precision floating point number to a    /// 32-bit signed integer. Note: the endianness of this converter does not    /// affect the returned value.    /// </summary>    /// <param name="value">The number to convert. </param>    /// <returns>A 32-bit signed integer whose value is equivalent to value.</returns>    public int SingleToInt32Bits(float value)    {      return new Int32SingleUnion(value).AsInt32;    }    /// <summary>    /// Converts the specified 32-bit signed integer to a single-precision floating point    /// number. Note: the endianness of this converter does not    /// affect the returned value.    /// </summary>    /// <param name="value">The number to convert. </param>    /// <returns>A single-precision floating point number whose value is equivalent to value.</returns>    public float Int32BitsToSingle (int value)    {      return new Int32SingleUnion(value).AsSingle;    }    #endregion    #region To(PrimitiveType) conversions    /// <summary>    /// Returns a Boolean value converted from one byte at a specified position in a byte array.    /// </summary>    /// <param name="value">An array of bytes.</param>    /// <param name="startIndex">The starting position within value.</param>    /// <returns>true if the byte at startIndex in value is nonzero; otherwise, false.</returns>    public bool ToBoolean (byte[] value, int startIndex)    {      CheckByteArgument(value, startIndex, 1);      return BitConverter.ToBoolean(value, startIndex);    }    /// <summary>    /// Returns a Unicode character converted from two bytes at a specified position in a byte array.    /// </summary>    /// <param name="value">An array of bytes.</param>    /// <param name="startIndex">The starting position within value.</param>    /// <returns>A character formed by two bytes beginning at startIndex.</returns>    public char ToChar (byte[] value, int startIndex)    {      return unchecked((char) (CheckedFromBytes(value, startIndex, 2)));    }    /// <summary>    /// Returns a double-precision floating point number converted from eight bytes    /// at a specified position in a byte array.    /// </summary>    /// <param name="value">An array of bytes.</param>    /// <param name="startIndex">The starting position within value.</param>    /// <returns>A double precision floating point number formed by eight bytes beginning at startIndex.</returns>    public double ToDouble (byte[] value, int startIndex)    {      return Int64BitsToDouble(ToInt64(value, startIndex));    }    /// <summary>    /// Returns a single-precision floating point number converted from four bytes    /// at a specified position in a byte array.    /// </summary>    /// <param name="value">An array of bytes.</param>    /// <param name="startIndex">The starting position within value.</param>    /// <returns>A single precision floating point number formed by four bytes beginning at startIndex.</returns>    public float ToSingle (byte[] value, int startIndex)    {      return Int32BitsToSingle(ToInt32(value, startIndex));    }    /// <summary>    /// Returns a 16-bit signed integer converted from two bytes at a specified position in a byte array.    /// </summary>    /// <param name="value">An array of bytes.</param>    /// <param name="startIndex">The starting position within value.</param>    /// <returns>A 16-bit signed integer formed by two bytes beginning at startIndex.</returns>    public short ToInt16 (byte[] value, int startIndex)    {      return unchecked((short) (CheckedFromBytes(value, startIndex, 2)));    }    /// <summary>    /// Returns a 32-bit signed integer converted from four bytes at a specified position in a byte array.    /// </summary>    /// <param name="value">An array of bytes.</param>    /// <param name="startIndex">The starting position within value.</param>    /// <returns>A 32-bit signed integer formed by four bytes beginning at startIndex.</returns>    public int ToInt32 (byte[] value, int startIndex)    {      return unchecked((int) (CheckedFromBytes(value, startIndex, 4)));    }    /// <summary>    /// Returns a 64-bit signed integer converted from eight bytes at a specified position in a byte array.    /// </summary>    /// <param name="value">An array of bytes.</param>    /// <param name="startIndex">The starting position within value.</param>    /// <returns>A 64-bit signed integer formed by eight bytes beginning at startIndex.</returns>    public long ToInt64 (byte[] value, int startIndex)    {      return CheckedFromBytes(value, startIndex, 8);    }    /// <summary>    /// Returns a 16-bit unsigned integer converted from two bytes at a specified position in a byte array.    /// </summary>    /// <param name="value">An array of bytes.</param>    /// <param name="startIndex">The starting position within value.</param>    /// <returns>A 16-bit unsigned integer formed by two bytes beginning at startIndex.</returns>    public ushort ToUInt16 (byte[] value, int startIndex)    {      return unchecked((ushort) (CheckedFromBytes(value, startIndex, 2)));    }    /// <summary>    /// Returns a 32-bit unsigned integer converted from four bytes at a specified position in a byte array.    /// </summary>    /// <param name="value">An array of bytes.</param>    /// <param name="startIndex">The starting position within value.</param>    /// <returns>A 32-bit unsigned integer formed by four bytes beginning at startIndex.</returns>    public uint ToUInt32 (byte[] value, int startIndex)    {      return unchecked((uint) (CheckedFromBytes(value, startIndex, 4)));    }    /// <summary>    /// Returns a 64-bit unsigned integer converted from eight bytes at a specified position in a byte array.    /// </summary>    /// <param name="value">An array of bytes.</param>    /// <param name="startIndex">The starting position within value.</param>    /// <returns>A 64-bit unsigned integer formed by eight bytes beginning at startIndex.</returns>    public ulong ToUInt64 (byte[] value, int startIndex)    {      return unchecked((ulong) (CheckedFromBytes(value, startIndex, 8)));    }    /// <summary>    /// Checks the given argument for validity.    /// </summary>    /// <param name="value">The byte array passed in</param>    /// <param name="startIndex">The start index passed in</param>    /// <param name="bytesRequired">The number of bytes required</param>    /// <exception cref="ArgumentNullException">value is a null reference</exception>    /// <exception cref="ArgumentOutOfRangeException">    /// startIndex is less than zero or greater than the length of value minus bytesRequired.    /// </exception>    static void CheckByteArgument(byte[] value, int startIndex, int bytesRequired)    {      if (value==null)      {        throw new ArgumentNullException("value");      }      if (startIndex < 0 || startIndex > value.Length-bytesRequired)      {        throw new ArgumentOutOfRangeException("startIndex");      }    }    /// <summary>    /// Checks the arguments for validity before calling FromBytes    /// (which can therefore assume the arguments are valid).    /// </summary>    /// <param name="value">The bytes to convert after checking</param>    /// <param name="startIndex">The index of the first byte to convert</param>    /// <param name="bytesToConvert">The number of bytes to convert</param>    /// <returns></returns>    long CheckedFromBytes(byte[] value, int startIndex, int bytesToConvert)    {      CheckByteArgument(value, startIndex, bytesToConvert);      return FromBytes(value, startIndex, bytesToConvert);    }    /// <summary>    /// Convert the given number of bytes from the given array, from the given start    /// position, into a long, using the bytes as the least significant part of the long.    /// By the time this is called, the arguments have been checked for validity.    /// </summary>    /// <param name="value">The bytes to convert</param>    /// <param name="startIndex">The index of the first byte to convert</param>    /// <param name="bytesToConvert">The number of bytes to use in the conversion</param>    /// <returns>The converted number</returns>    protected abstract long FromBytes(byte[] value, int startIndex, int bytesToConvert);    #endregion    #region ToString conversions    /// <summary>    /// Returns a String converted from the elements of a byte array.    /// </summary>    /// <param name="value">An array of bytes.</param>    /// <remarks>All the elements of value are converted.</remarks>    /// <returns>    /// A String of hexadecimal pairs separated by hyphens, where each pair    /// represents the corresponding element in value; for example, "7F-2C-4A".    /// </returns>    public static string ToString(byte[] value)    {      return BitConverter.ToString(value);    }    /// <summary>    /// Returns a String converted from the elements of a byte array starting at a specified array position.    /// </summary>    /// <param name="value">An array of bytes.</param>    /// <param name="startIndex">The starting position within value.</param>    /// <remarks>The elements from array position startIndex to the end of the array are converted.</remarks>    /// <returns>    /// A String of hexadecimal pairs separated by hyphens, where each pair    /// represents the corresponding element in value; for example, "7F-2C-4A".    /// </returns>    public static string ToString(byte[] value, int startIndex)    {      return BitConverter.ToString(value, startIndex);    }    /// <summary>    /// Returns a String converted from a specified number of bytes at a specified position in a byte array.    /// </summary>    /// <param name="value">An array of bytes.</param>    /// <param name="startIndex">The starting position within value.</param>    /// <param name="length">The number of bytes to convert.</param>    /// <remarks>The length elements from array position startIndex are converted.</remarks>    /// <returns>    /// A String of hexadecimal pairs separated by hyphens, where each pair    /// represents the corresponding element in value; for example, "7F-2C-4A".    /// </returns>    public static string ToString(byte[] value, int startIndex, int length)    {      return BitConverter.ToString(value, startIndex, length);    }    #endregion    #region  Decimal conversions    /// <summary>    /// Returns a decimal value converted from sixteen bytes    /// at a specified position in a byte array.    /// </summary>    /// <param name="value">An array of bytes.</param>    /// <param name="startIndex">The starting position within value.</param>    /// <returns>A decimal formed by sixteen bytes beginning at startIndex.</returns>    public decimal ToDecimal (byte[] value, int startIndex)    {      // HACK: This always assumes four parts, each in their own endianness,      // starting with the first part at the start of the byte array.      // On the other hand, there's no real format specified...      int[] parts = new int[4];      for (int i=0; i < 4; i++)      {        parts[i] = ToInt32(value, startIndex+i*4);      }      return new Decimal(parts);    }    /// <summary>    /// Returns the specified decimal value as an array of bytes.    /// </summary>    /// <param name="value">The number to convert.</param>    /// <returns>An array of bytes with length 16.</returns>    public byte[] GetBytes(decimal value)    {      byte[] bytes = new byte[16];      int[] parts = decimal.GetBits(value);      for (int i=0; i < 4; i++)      {        CopyBytesImpl(parts[i], 4, bytes, i*4);      }      return bytes;    }    /// <summary>    /// Copies the specified decimal value into the specified byte array,    /// beginning at the specified index.    /// </summary>    /// <param name="value">A character to convert.</param>    /// <param name="buffer">The byte array to copy the bytes into</param>    /// <param name="index">The first index into the array to copy the bytes into</param>    public void CopyBytes(decimal value, byte[] buffer, int index)    {      int[] parts = decimal.GetBits(value);      for (int i=0; i < 4; i++)      {        CopyBytesImpl(parts[i], 4, buffer, i*4+index);      }    }    #endregion    #region GetBytes conversions    /// <summary>    /// Returns an array with the given number of bytes formed    /// from the least significant bytes of the specified value.    /// This is used to implement the other GetBytes methods.    /// </summary>    /// <param name="value">The value to get bytes for</param>    /// <param name="bytes">The number of significant bytes to return</param>    byte[] GetBytes(long value, int bytes)    {      byte[] buffer = new byte[bytes];      CopyBytes(value, bytes, buffer, 0);      return buffer;    }    /// <summary>    /// Returns the specified Boolean value as an array of bytes.    /// </summary>    /// <param name="value">A Boolean value.</param>    /// <returns>An array of bytes with length 1.</returns>    public byte[] GetBytes(bool value)    {      return BitConverter.GetBytes(value);    }    /// <summary>    /// Returns the specified Unicode character value as an array of bytes.    /// </summary>    /// <param name="value">A character to convert.</param>    /// <returns>An array of bytes with length 2.</returns>    public byte[] GetBytes(char value)    {      return GetBytes(value, 2);    }    /// <summary>    /// Returns the specified double-precision floating point value as an array of bytes.    /// </summary>    /// <param name="value">The number to convert.</param>    /// <returns>An array of bytes with length 8.</returns>    public byte[] GetBytes(double value)    {      return GetBytes(DoubleToInt64Bits(value), 8);    }    /// <summary>    /// Returns the specified 16-bit signed integer value as an array of bytes.    /// </summary>    /// <param name="value">The number to convert.</param>    /// <returns>An array of bytes with length 2.</returns>    public byte[] GetBytes(short value)    {      return GetBytes(value, 2);    }    /// <summary>    /// Returns the specified 32-bit signed integer value as an array of bytes.    /// </summary>    /// <param name="value">The number to convert.</param>    /// <returns>An array of bytes with length 4.</returns>    public byte[] GetBytes(int value)    {      return GetBytes(value, 4);    }    /// <summary>    /// Returns the specified 64-bit signed integer value as an array of bytes.    /// </summary>    /// <param name="value">The number to convert.</param>    /// <returns>An array of bytes with length 8.</returns>    public byte[] GetBytes(long value)    {      return GetBytes(value, 8);    }    /// <summary>    /// Returns the specified single-precision floating point value as an array of bytes.    /// </summary>    /// <param name="value">The number to convert.</param>    /// <returns>An array of bytes with length 4.</returns>    public byte[] GetBytes(float value)    {      return GetBytes(SingleToInt32Bits(value), 4);    }    /// <summary>    /// Returns the specified 16-bit unsigned integer value as an array of bytes.    /// </summary>    /// <param name="value">The number to convert.</param>    /// <returns>An array of bytes with length 2.</returns>    public byte[] GetBytes(ushort value)    {      return GetBytes(value, 2);    }    /// <summary>    /// Returns the specified 32-bit unsigned integer value as an array of bytes.    /// </summary>    /// <param name="value">The number to convert.</param>    /// <returns>An array of bytes with length 4.</returns>    public byte[] GetBytes(uint value)    {      return GetBytes(value, 4);    }    /// <summary>    /// Returns the specified 64-bit unsigned integer value as an array of bytes.    /// </summary>    /// <param name="value">The number to convert.</param>    /// <returns>An array of bytes with length 8.</returns>    public byte[] GetBytes(ulong value)    {      return GetBytes(unchecked((long)value), 8);    }    #endregion    #region CopyBytes conversions    /// <summary>    /// Copies the given number of bytes from the least-specific    /// end of the specified value into the specified byte array, beginning    /// at the specified index.    /// This is used to implement the other CopyBytes methods.    /// </summary>    /// <param name="value">The value to copy bytes for</param>    /// <param name="bytes">The number of significant bytes to copy</param>    /// <param name="buffer">The byte array to copy the bytes into</param>    /// <param name="index">The first index into the array to copy the bytes into</param>    void CopyBytes(long value, int bytes, byte[] buffer, int index)    {      if (buffer==null)      {        throw new ArgumentNullException("buffer", "Byte array must not be null");      }      if (buffer.Length < index+bytes)      {        throw new ArgumentOutOfRangeException("Buffer not big enough for value");      }      CopyBytesImpl(value, bytes, buffer, index);    }    /// <summary>    /// Copies the given number of bytes from the least-specific    /// end of the specified value into the specified byte array, beginning    /// at the specified index.    /// This must be implemented in concrete derived classes, but the implementation    /// may assume that the value will fit into the buffer.    /// </summary>    /// <param name="value">The value to copy bytes for</param>    /// <param name="bytes">The number of significant bytes to copy</param>    /// <param name="buffer">The byte array to copy the bytes into</param>    /// <param name="index">The first index into the array to copy the bytes into</param>    protected abstract void CopyBytesImpl(long value, int bytes, byte[] buffer, int index);    /// <summary>    /// Copies the specified Boolean value into the specified byte array,    /// beginning at the specified index.    /// </summary>    /// <param name="value">A Boolean value.</param>    /// <param name="buffer">The byte array to copy the bytes into</param>    /// <param name="index">The first index into the array to copy the bytes into</param>    public void CopyBytes(bool value, byte[] buffer, int index)    {      CopyBytes(value ? 1 : 0, 1, buffer, index);    }    /// <summary>    /// Copies the specified Unicode character value into the specified byte array,    /// beginning at the specified index.    /// </summary>    /// <param name="value">A character to convert.</param>    /// <param name="buffer">The byte array to copy the bytes into</param>    /// <param name="index">The first index into the array to copy the bytes into</param>    public void CopyBytes(char value, byte[] buffer, int index)    {      CopyBytes(value, 2, buffer, index);    }    /// <summary>    /// Copies the specified double-precision floating point value into the specified byte array,    /// beginning at the specified index.    /// </summary>    /// <param name="value">The number to convert.</param>    /// <param name="buffer">The byte array to copy the bytes into</param>    /// <param name="index">The first index into the array to copy the bytes into</param>    public void CopyBytes(double value, byte[] buffer, int index)    {      CopyBytes(DoubleToInt64Bits(value), 8, buffer, index);    }    /// <summary>    /// Copies the specified 16-bit signed integer value into the specified byte array,    /// beginning at the specified index.    /// </summary>    /// <param name="value">The number to convert.</param>    /// <param name="buffer">The byte array to copy the bytes into</param>    /// <param name="index">The first index into the array to copy the bytes into</param>    public void CopyBytes(short value, byte[] buffer, int index)    {      CopyBytes(value, 2, buffer, index);    }    /// <summary>    /// Copies the specified 32-bit signed integer value into the specified byte array,    /// beginning at the specified index.    /// </summary>    /// <param name="value">The number to convert.</param>    /// <param name="buffer">The byte array to copy the bytes into</param>    /// <param name="index">The first index into the array to copy the bytes into</param>    public void CopyBytes(int value, byte[] buffer, int index)    {      CopyBytes(value, 4, buffer, index);    }    /// <summary>    /// Copies the specified 64-bit signed integer value into the specified byte array,    /// beginning at the specified index.    /// </summary>    /// <param name="value">The number to convert.</param>    /// <param name="buffer">The byte array to copy the bytes into</param>    /// <param name="index">The first index into the array to copy the bytes into</param>    public void CopyBytes(long value, byte[] buffer, int index)    {      CopyBytes(value, 8, buffer, index);    }    /// <summary>    /// Copies the specified single-precision floating point value into the specified byte array,    /// beginning at the specified index.    /// </summary>    /// <param name="value">The number to convert.</param>    /// <param name="buffer">The byte array to copy the bytes into</param>    /// <param name="index">The first index into the array to copy the bytes into</param>    public void CopyBytes(float value, byte[] buffer, int index)    {      CopyBytes(SingleToInt32Bits(value), 4, buffer, index);    }    /// <summary>    /// Copies the specified 16-bit unsigned integer value into the specified byte array,    /// beginning at the specified index.    /// </summary>    /// <param name="value">The number to convert.</param>    /// <param name="buffer">The byte array to copy the bytes into</param>    /// <param name="index">The first index into the array to copy the bytes into</param>    public void CopyBytes(ushort value, byte[] buffer, int index)    {      CopyBytes(value, 2, buffer, index);    }    /// <summary>    /// Copies the specified 32-bit unsigned integer value into the specified byte array,    /// beginning at the specified index.    /// </summary>    /// <param name="value">The number to convert.</param>    /// <param name="buffer">The byte array to copy the bytes into</param>    /// <param name="index">The first index into the array to copy the bytes into</param>    public void CopyBytes(uint value, byte[] buffer, int index)    {      CopyBytes(value, 4, buffer, index);    }    /// <summary>    /// Copies the specified 64-bit unsigned integer value into the specified byte array,    /// beginning at the specified index.    /// </summary>    /// <param name="value">The number to convert.</param>    /// <param name="buffer">The byte array to copy the bytes into</param>    /// <param name="index">The first index into the array to copy the bytes into</param>    public void CopyBytes(ulong value, byte[] buffer, int index)    {      CopyBytes(unchecked((long)value), 8, buffer, index);    }    #endregion    #region Private struct used for Single/Int32 conversions    /// <summary>    /// Union used solely for the equivalent of DoubleToInt64Bits and vice versa.    /// </summary>    [StructLayout(LayoutKind.Explicit)]      struct Int32SingleUnion    {      /// <summary>      /// Int32 version of the value.      /// </summary>      [FieldOffset(0)]      int i;      /// <summary>      /// Single version of the value.      /// </summary>      [FieldOffset(0)]      float f;      /// <summary>      /// Creates an instance representing the given integer.      /// </summary>      /// <param name="i">The integer value of the new instance.</param>      internal Int32SingleUnion(int i)      {        this.f = 0; // Just to keep the compiler happy        this.i = i;      }      /// <summary>      /// Creates an instance representing the given floating point number.      /// </summary>      /// <param name="f">The floating point value of the new instance.</param>      internal Int32SingleUnion(float f)      {        this.i = 0; // Just to keep the compiler happy        this.f = f;      }      /// <summary>      /// Returns the value of the instance as an integer.      /// </summary>      internal int AsInt32      {        get { return i; }      }      /// <summary>      /// Returns the value of the instance as a floating point number.      /// </summary>      internal float AsSingle      {        get { return f; }      }    }    #endregion  }}

EndianBitConverter

第二部分

namespace MiscUtil.Conversion{  /// <summary>  /// Implementation of EndianBitConverter which converts to/from big-endian  /// byte arrays.  /// </summary>  public sealed class BigEndianBitConverter : EndianBitConverter  {    /// <summary>    /// Indicates the byte order ("endianess") in which data is converted using this class.    /// </summary>    /// <remarks>    /// Different computer architectures store data using different byte orders. "Big-endian"    /// means the most significant byte is on the left end of a word. "Little-endian" means the    /// most significant byte is on the right end of a word.    /// </remarks>    /// <returns>true if this converter is little-endian, false otherwise.</returns>    public sealed override bool IsLittleEndian()    {      return false;    }    /// <summary>    /// Indicates the byte order ("endianess") in which data is converted using this class.    /// </summary>    public sealed override Endianness Endianness    {      get { return Endianness.BigEndian; }    }    /// <summary>    /// Copies the specified number of bytes from value to buffer, starting at index.    /// </summary>    /// <param name="value">The value to copy</param>    /// <param name="bytes">The number of bytes to copy</param>    /// <param name="buffer">The buffer to copy the bytes into</param>    /// <param name="index">The index to start at</param>    protected override void CopyBytesImpl(long value, int bytes, byte[] buffer, int index)    {      int endOffset = index+bytes-1;      for (int i=0; i < bytes; i++)      {        buffer[endOffset-i] = unchecked((byte)(value&0xff));        value = value >> 8;      }    }    /// <summary>    /// Returns a value built from the specified number of bytes from the given buffer,    /// starting at index.    /// </summary>    /// <param name="buffer">The data in byte array format</param>    /// <param name="startIndex">The first index to use</param>    /// <param name="bytesToConvert">The number of bytes to use</param>    /// <returns>The value built from the given bytes</returns>    protected override long FromBytes(byte[] buffer, int startIndex, int bytesToConvert)    {      long ret = 0;      for (int i=0; i < bytesToConvert; i++)      {        ret = unchecked((ret << 8) | buffer[startIndex+i]);      }      return ret;    }  }}

BigEndianBitConverter

第三部分

namespace MiscUtil.Conversion{  /// <summary>  /// Endianness of a converter  /// </summary>  public enum Endianness  {    /// <summary>    /// Little endian - least significant byte first    /// </summary>    LittleEndian,    /// <summary>    /// Big endian - most significant byte first    /// </summary>    BigEndian  }}

Endianness

第四部分

namespace MiscUtil.Conversion{  /// <summary>  /// Implementation of EndianBitConverter which converts to/from little-endian  /// byte arrays.  /// </summary>  public sealed class LittleEndianBitConverter : EndianBitConverter  {    /// <summary>    /// Indicates the byte order ("endianess") in which data is converted using this class.    /// </summary>    /// <remarks>    /// Different computer architectures store data using different byte orders. "Big-endian"    /// means the most significant byte is on the left end of a word. "Little-endian" means the    /// most significant byte is on the right end of a word.    /// </remarks>    /// <returns>true if this converter is little-endian, false otherwise.</returns>    public sealed override bool IsLittleEndian()    {      return true;    }    /// <summary>    /// Indicates the byte order ("endianess") in which data is converted using this class.    /// </summary>    public sealed override Endianness Endianness    {      get { return Endianness.LittleEndian; }    }    /// <summary>    /// Copies the specified number of bytes from value to buffer, starting at index.    /// </summary>    /// <param name="value">The value to copy</param>    /// <param name="bytes">The number of bytes to copy</param>    /// <param name="buffer">The buffer to copy the bytes into</param>    /// <param name="index">The index to start at</param>    protected override void CopyBytesImpl(long value, int bytes, byte[] buffer, int index)    {      for (int i=0; i < bytes; i++)      {        buffer[i+index] = unchecked((byte)(value&0xff));        value = value >> 8;      }    }    /// <summary>    /// Returns a value built from the specified number of bytes from the given buffer,    /// starting at index.    /// </summary>    /// <param name="buffer">The data in byte array format</param>    /// <param name="startIndex">The first index to use</param>    /// <param name="bytesToConvert">The number of bytes to use</param>    /// <returns>The value built from the given bytes</returns>    protected override long FromBytes(byte[] buffer, int startIndex, int bytesToConvert)    {      long ret = 0;      for (int i=0; i < bytesToConvert; i++)      {        ret = unchecked((ret << 8) | buffer[startIndex+bytesToConvert-1-i]);      }      return ret;    }  }}

LittleEndianBitConverter