Can you explain you shared Advance function?

[btgvesta]

Hello,

Can you explain your shared Advanced(buffer* Buffer, umw Count) in C?

[bagaffey]

Yeah, what it is doing is advancing a buffer by Count number of bytes (unsigned machine word).

There's two cases:

1. When the Count is the size or smaller than the size of the buffer. The result pointer is pointed at the start of the buffer when it was passed in. The buffer's length is advanced by Count number of 8-bit bytes. This effectively slices a segment, that is Count long, off the start of the buffer.
2. When the Count is larger than the length of the buffer then the buffer is exhausted i.e. its length is set to 0 after advancing the buffer to its end. The result pointer is kept at 0 (pointing at nothing). This is intentional so that the caller knows that the advance could not return a slice of the buffer that was Count long.
   That is also to indicate a failure state. This way the caller does not assume that it was able to successfully pull a slice of the buffer that is Count long when it isn't possible. The Buffer->Count =0 and the invalid pointer indicate to the caller that the advance failed.