Byte swapping help please 962

Looks like it.

In principle, there is no reliable way to tell. If you read a 32-bit unsigned integer from a file and get a value of 0xABCDEF01, how can you know whether it should be 0xABCDEF01 or 0x01EFCDAB? Without more information, you can't. Even with more information, you may not be able to tell.

If you're storing binary data in a file, byte ordering is only one of the problems you can run into. Sizes of types can vary across different implementations; so cah floating-point representations.

The safest approach is to write *only* byte data. For example, if you want to write an integer value 0x01EFCDAB to a file, you can read and write the individual bytes (0x01, 0xEF, 0xCD, 0xAB) in a fixed order. Or you can write a textual representation of the number, which also has the advantage of letting you view the file with a text editor.

Strictly speaking, you might still have problems on systems with byte sizes bigger than 8 bits, or with non-ASCII character sets; the former is unlikely to arise in practice, and the latter can be solved with textual conversion tools. (There are systems, mostly DSPs, with bytes bigger than 8 bits, but they're embedded systems, and you're not likely to need to share files with them.)

If you must write raw binary data to a file, you might add information to the file header indicating how the data is formatted.

-- We must do something. This is something. Therefore, we must do this.