simon-git: puzzles (main): Ben Harris

[Commits to Tartarus hosted VCS]

TL;DR:
  6db5cda Blackbox: correct FROMDRAW() macro for C division semantics

Repository:     https://git.tartarus.org/simon/puzzles.git
On the web:     https://git.tartarus.org/?p=simon/puzzles.git
Branch updated: main
Committer:      Ben Harris <bjh21 at bjh21.me.uk>
Date:           2023-06-22 23:10:31

commit 6db5cdadd09fad0c8373e32dcfc7ab5b8bcb74e6
web diff https://git.tartarus.org/?p=simon/puzzles.git;a=commitdiff;h=6db5cdadd09fad0c8373e32dcfc7ab5b8bcb74e6;hp=da014d23dad4bcff0215d9ba7758652c85c06a20
Author: Ben Harris <bjh21 at bjh21.me.uk>
Date:   Thu Jun 22 23:08:19 2023 +0100

    Blackbox: correct FROMDRAW() macro for C division semantics
    
    Integer division in C rounds towards zero, so if you want it to
    consistently round down you need to ensure that the arguments are
    positive.  FROMDRAW() didn't do that, so clicks off the top and left
    corners of the grid got treated as being in the top row or left column
    (row and column 0) rather than ignored.
    
    This commit fixes the macro so that it offsets its argument upward
    before the division and compensates afterwards.

 blackbox.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)