I’ve looked around the net a bit for more information on this question and there is a quite a range of answers and reasonings to explain why big or little endian ordering may be preferable. I’ll do my best to explain here what I found: Little-endian The obvious advantage to little-endianness is what you mentioned … Read more
This code violates the strict aliasing rules which makes it illegal to access an object through a pointer of a different type, although access through a *char ** is allowed. The compiler is allowed to assume that pointers of different types do not point to the same memory and optimize accordingly. It also means the … Read more
Without a doubt, you are correct. ANSI C standard 6.1.4 specifies that string literals are stored in memory by “concatenating” the characters in the literal. ANSI standard 6.3.6 also specifies the effect of addition on a pointer value: When an expression that has integral type is added to or subtracted from a pointer, the result … Read more
When adding two numbers (on paper or in a machine), you start with the least significant digits and work towards the most significant digits. (Same goes for many other operations). On the Intel 8088, which had 16-bit registers but an 8-bit data bus, being little-endian allowed such instructions to start operation after the first memory … Read more
What the standard says [intro.abstract]/1: The semantic descriptions in this document define a parameterized nondeterministic abstract machine. This document places no requirement on the structure of conforming implementations. In particular, they need not copy or emulate the structure of the abstract machine. Rather, conforming implementations are required to emulate (only) the observable behavior of the … Read more
If you’re looking for performance then you could use Buffer.BlockCopy. Nice and simple, and probably about as fast as you’ll get in managed code. var floatArray1 = new float[] { 123.45f, 123f, 45f, 1.2f, 34.5f }; // create a byte array and copy the floats into it… var byteArray = new byte[floatArray1.Length * 4]; Buffer.BlockCopy(floatArray1, … Read more
Largely, for the same reason you start at the least significant digit (the right end) when you add—because carries propagate toward the more significant digits. Putting the least significant byte first allows the processor to get started on the add after having read only the first byte of an offset. After you’ve done enough assembly … Read more
C# itself doesn’t define the endianness. Whenever you convert to bytes, however, you’re making a choice. The BitConverter class has an IsLittleEndian field to tell you how it will behave, but it doesn’t give the choice. The same goes for BinaryReader/BinaryWriter. My MiscUtil library has an EndianBitConverter class which allows you to define the endianness; … Read more
Very abstractly speaking, endianness is a property of the reinterpretation of a variable as a char-array. Practically, this matters precisely when you read() from and write() to an external byte stream (like a file or a socket). Or, speaking abstractly again, endianness matters when you serialize data (essentially because serialized data has no type system … Read more
Big-Endian (BE) / Little-Endian (LE) are two ways to organize multi-byte words. For example, when using two bytes to represent a character in UTF-16, there are two ways to represent the character 0x1234 as a string of bytes (0x00-0xFF): Byte Index: 0 1 ——————— Big-Endian: 12 34 Little-Endian: 34 12 In order to decide if … Read more