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  • 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
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  • 原文地址:https://www.cnblogs.com/mokeyish/p/5042812.html
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