From e77c7766cd76b579dc12cbceafea25c03b79f446 Mon Sep 17 00:00:00 2001
From: Bill Kendrick <nbs@sonic.net>
Date: Sat, 20 Nov 2021 01:52:43 -0800
Subject: [PATCH] Fill queue is now actually a stack

Size of queue structure (which contains 3 ints, so is 12 bytes on
my Linux laptop) before & after, when filling a few sample images
when running in a 3000x2000 window:

 * a pattern i drew
   queue:   855,040
   stack:   287,744

 * mosaic
   queue:   908,288
   stack:   398,336

 * mosaic 4x via panel magic tool
   queue: 1,451,008
   stack:   734,208
---
 src/fill.c | 20 +++++++++-----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/src/fill.c b/src/fill.c
index d3bb97212..042ee0bcb 100644
--- a/src/fill.c
+++ b/src/fill.c
@@ -69,7 +69,7 @@ typedef struct queue_s {
 } queue_t;
 
 queue_t * queue;
-int queue_size = 0, queue_start = 0, queue_end = 0;
+int queue_size = 0, queue_end = 0;
 
 /* Local function prototypes: */
 
@@ -91,7 +91,6 @@ void cleanup_queue(void);
 
 void init_queue(void) {
   queue_size = 0;
-  queue_start = 0;
   queue_end = 0;
 
   queue = (queue_t *) malloc(sizeof(queue_t) * QUEUE_SIZE_CHUNK);
@@ -139,19 +138,19 @@ void add_to_queue(int x, int y, int y_outside) {
 }
 
 int remove_from_queue(int * x, int * y, int * y_outside) {
-  if (queue_start == queue_end)
+  if (queue_end == 0)
     return 0;
 
-  *x = queue[queue_start].x;
-  *y = queue[queue_start].y;
-  *y_outside = queue[queue_start].y_outside;
+  queue_end--;
 
-  queue_start++;
+  *x = queue[queue_end].x;
+  *y = queue[queue_end].y;
+  *y_outside = queue[queue_end].y_outside;
 
 #ifdef DEBUG
-  if (queue_start % 100 == 0)
+  if (queue_end % 100 == 0)
     {
-      printf("queue_start = %d\n", queue_start);
+      printf("queue_end = %d\n", queue_end);
       fflush(stdout);
     }
 #endif
@@ -164,11 +163,10 @@ void cleanup_queue(void) {
     free(queue);
 
 #ifdef DEBUG
-  printf("queue_size = %d\n\n", queue_size);
+  printf("Final size was %d\n", queue_size);
 #endif
 
   queue_size = 0;
-  queue_start = 0;
   queue_end = 0;
 }