Scratch

As a general solution to whatever you're solving, you could try Google Protocol Buffers. It's C++, but I think you can use C++ code in Xcode (assuming that's what you're using). Just a thought. 

Otherwise, I think you want to use the bitshift operator; something like this:

int a, b, c, d;
int big = a << 24  +  b << 16  +  c << 8  + d;

(I'm afraid I'm not so good on C types -- maybe it should be unsigned char or long or something somewhere. Hope that helps, anyhow    )

Last edited by blob8108 (2012-01-30 05:58:23)

I think you meant this:

int big = a << 24  |  b << 16  |  c << 8  | d;

Hardmath123 wrote:

So given ints a, b, c, d; how do I construct a 32-bit big-endian? Just give me a formula...

I'm sorry; I'm not sure I understand what you're asking. Are you trying to write that 32-bit int to a file?

Make it of type unsigned int, rather than int. (it basically says big numbers are not negative)

Hardmath123 wrote:

As a digression, I would really appreciate a bunch of notes on byte arrays. Is far as I know, they're arrays of integers constructed from data.

A byte array is just that -- an array of bytes. (I think translates to an array of char in C.) The Scratch file format uses them to store strings (as characters can be translated to 8-bit integers using an encoding such as ASCII or UT8). Their format consists of a 4-byte (32-bit) integer describing the length of the string, followed by that many bytes content.

See the little wiki I made if you need more detail -- it may help.    Image data is stored in Forms, according to nXIII -- see his post (which I copied to the wiki).

Anyhow, I'm glad you solved your immediate problem.