c#，關於Big Endian 和 Little Endian，以及轉換類，
Big Endian：最高字節在地址最低位，最低字節在地址最高位，依次排列。
Little Endian：最低字節在最低位，最高字節在最高位，反序排列。
當在本地主機上，無需注意機器用的是Big Endian還是Little Endian。但是網絡上都是用的是Big Endian，需要進行一個轉換，但是c#提供的BitConverter默認使用的Little Endian，在需與網絡通信時，反的字節序大有不便，特此提供一個可選Big Endian和Little Endian類方便轉換。
為什麼存在Little Endian？因為對於機器來說，Little Endian更有利於機器的運算。內存地址由低位到高位，在兩個數相加運算，直接在高位添加進位數，不必移動內存地址
第一部分
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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
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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
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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
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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
