[hitori] Bug 575896 — Improve board generation algorithm

[Philip Withnall <pwithnall src gnome org>]

commit 9f3ec3ad305b266908488fc597ca4a40f9999cf0
Author: Philip Withnall <philip tecnocode co uk>
Date:   Thu Oct 28 10:31:24 2010 +0100

    Bug 575896 â?? Improve board generation algorithm
    
    The algorithm wasn't allowing any painted cells at the edge of the board.
    This fixes that problem, and improves the code documentation a little.
    Closes: bgo#575896

 src/generator.c |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)
---
diff --git a/src/generator.c b/src/generator.c
index c7f12e4..c168dad 100644
--- a/src/generator.c
+++ b/src/generator.c
@@ -65,14 +65,15 @@ hitori_generate_board (Hitori *hitori, guint new_board_size, gint seed)
 	 * cells, and only specifying it for 8x8 grids. This will change in the
 	 * future. */
 	for (i = 0; i < total; i++) {
+		/* Generate pairs of coordinates until we find one which lies between unpainted cells (or at the edge of the board) */
 		do {
 			iter.x = rand () % hitori->board_size;
 			iter.y = rand () % hitori->board_size;
 
-			if (iter.y >= 1 && (hitori->board[iter.x][iter.y-1].status & CELL_PAINTED) == FALSE &&
-			    iter.y + 1 < hitori->board_size && (hitori->board[iter.x][iter.y+1].status & CELL_PAINTED) == FALSE &&
-			    iter.x >= 1 && (hitori->board[iter.x-1][iter.y].status & CELL_PAINTED) == FALSE &&
-			    iter.x + 1 < hitori->board_size && (hitori->board[iter.x+1][iter.y].status & CELL_PAINTED) == FALSE)
+			if ((iter.y < 1 || (hitori->board[iter.x][iter.y-1].status & CELL_PAINTED) == FALSE) &&
+			    (iter.y + 1 >= hitori->board_size || (hitori->board[iter.x][iter.y+1].status & CELL_PAINTED) == FALSE) &&
+			    (iter.x < 1 || (hitori->board[iter.x-1][iter.y].status & CELL_PAINTED) == FALSE) &&
+			    (iter.x + 1 >= hitori->board_size || (hitori->board[iter.x+1][iter.y].status & CELL_PAINTED) == FALSE))
 				break;
 		} while (TRUE);