Implement ppq_remove() (possibly buggy idk)

2 files changed, 29 insertions, 0 deletions

diff --git a/priority_queue.c b/priority_queue.c
index de6c179..6460a9e 100644
--- a/priority_queue.c
+++ b/priority_queue.c
@@ -67,6 +67,32 @@ Position ppq_pop(PositionPQ **ppq) {
     return pos;
 }
 
+void ppq_remove(PositionPQ **ppq, Position pos) {
+    PositionPQ *temp = *ppq;
+
+    if (temp == NULL) {
+        error("Tried to remove a pos from a NULL PositionPQ\n");
+    }
+
+    PositionPQ *prev = NULL;
+
+    while (temp->next != NULL && (pos.x != temp->pos.x || pos.y != temp->pos.y)) {
+        prev = temp;
+        temp = temp->next;
+    }
+
+    if (pos.x == temp->pos.x && pos.y == temp->pos.y) {
+        if (prev != NULL) {
+            prev->next = temp->next;
+            free(temp);
+        } else {
+            prev = *ppq;
+            *ppq = (*ppq)->next;
+            free(prev);
+        }
+    }
+}
+
 void ppq_reprioritize(PositionPQ *ppq, Position pos, size_t priority) {
     (void)ppq, (void)pos, (void)priority;
     todo();
diff --git a/priority_queue.h b/priority_queue.h
index c121487..241dcc7 100644
--- a/priority_queue.h
+++ b/priority_queue.h
@@ -25,6 +25,9 @@ int ppq_insert(PositionPQ **ppq, Position pos, size_t priority);
 /* Remove and return the position with the lowest priority */
 Position ppq_pop(PositionPQ **ppq);
 
+/* Remove a given pos fron ppq */
+void ppq_remove(PositionPQ **ppq, Position pos);
+
 /* Change the priority of a given pos, moving it to a different place in the
  * linked list ("POTENTIALLY NOT NEEDED" since we don't use different weights */
 void ppq_reprioritize(PositionPQ *ppq, Position pos, size_t priority);