little-endian and big-endian-优快云博客

博客介绍了计算机架构中大小端的概念，大端是从左到右编号字节，小端是从右到左编号字节。还给出C#示例，有两个txt文件采用不同编码方式，分别用二进制和StreamReader读取内容，得出UCS - 2 Little Endian编码文件以FFFE开头，UCS - 2 Big Endian编码文件以FEFF开头的结论。

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Some computer architectures number bytes in a binary word from left to right, which is referred to as

big-endian.

Other architectures number the bytes in a binary word from right to left, which is referred to as little-endian.

Using big-endian and little-endian methods, the number 0x12345678 would be stored as shown in the following table.

Byte order

Byte 0

Byte 1

Byte 2

Byte 3

Big-endian

0x12

0x34

0x56

0x78

Little-endian

0x78

0x56

0x34

0x12

例子：
下面C# code中有2个txt文件：LittleEndian.txt和BigEndian.txt，他们包含相同的文本内容:都是aa，但不同的编码方式，分别是UCS-2 Little Endian 和UCS-2 Big Endian.

示例中先分别用二进制的方式读出文件中的内容；再用StreamReader读出文件的内容

 static void Main(string[] args)
        {
            byte[] leBytes = ReadAsBinary(".\\LittleEndian.txt");
            Console.WriteLine("Little Endian:");
            PrintByteArray(leBytes);
            Console.WriteLine();

            byte[] bigBytes = ReadAsBinary(".\\BigEndian.txt");
            Console.WriteLine("Big Endian:");
            PrintByteArray(bigBytes);
            Console.WriteLine();

            byte[] srByes;
            using (StreamReader reader = new StreamReader(".\\LittleEndian.txt", true))
            {
                srByes = Encoding.Unicode.GetBytes(reader.ReadToEnd());
            }
            Console.WriteLine("StreamReader Little Endian:");
            PrintByteArray(srByes);
            Console.WriteLine();
}

        private static byte[] ReadAsBinary(string path)
        {
            FileStream fs = new FileStream(path, FileMode.OpenOrCreate, FileAccess.Read);
            BinaryReader breader = new BinaryReader(fs);
            byte[] bytes = breader.ReadBytes(6);
            return bytes;
        }