fix: not adjusting head after realloc

- Big bug
- Tests passing
- Added test for push_ex

Author: tricktux

source/utils/queue.c

@@ -26,6 +26,7 @@ void queue_init_data(struct queue* qu, size_t capacity)
   qu->data = new_data;
   qu->capacity = capacity;
   qu->free_capacity = capacity - qu->size;
+  qu->head = qu->data + qu->size;
 }
 
 void queue_expand_capacity(struct queue* qu, size_t size)
@@ -34,11 +35,11 @@ void queue_expand_capacity(struct queue* qu, size_t size)
   if (size ==0)
     return;
 
-  if (qu->size + size < qu->free_capacity)
+  if (qu->size + size < (qu->free_capacity * QUEUE_FREE_CAP_BUFFER))
     return;
 
   size_t new_cap = qu->capacity * 2, new_free_cap = new_cap - qu->size;
-  while (qu->size + size >= new_free_cap) {
+  while (qu->size + size >= (new_free_cap * QUEUE_FREE_CAP_BUFFER)) {
     new_cap *= 2;
     new_free_cap = new_cap - qu->size;
   }
@@ -71,8 +72,6 @@ void queue_init(struct queue** qu, size_t capacity)
   (*qu)->size = 0;
   (*qu)->data = NULL;
   queue_init_data(*qu, capacity);
-
-  (*qu)->head = (*qu)->data;
 }
 
 /**
@@ -116,7 +115,7 @@ void queue_push(struct queue* qu, char* data, size_t size)
     return;
   }
 
-  if (qu->size + size >= qu->free_capacity) {
+  if (qu->size + size >= (qu->free_capacity * QUEUE_FREE_CAP_BUFFER)) {
     queue_expand_capacity(qu, size);
     log_info("queue_push: expanding current capacity to %d\n", qu->capacity);
   }
@@ -146,7 +145,7 @@ void queue_push_ex(struct queue* qu, size_t size)
     return;
   }
 
-  if (qu->size + size >= qu->free_capacity) {
+  if (qu->size + size >= (qu->free_capacity * QUEUE_FREE_CAP_BUFFER)) {
     queue_expand_capacity(qu, size);
     log_info("queue_push: expanding current capacity to %d\n", qu->capacity);
   }

source/utils/queue.h

@@ -5,6 +5,8 @@
 extern "C" {
 #endif
 
+#define QUEUE_FREE_CAP_BUFFER 0.5  // Percentage
+
 struct queue {
   char* data;
   size_t capacity;

test/queue/queue-test.cpp

@@ -90,7 +90,19 @@ TEST_CASE("Queue Edge Cases")
 
     // As it should over push the capacity, size should remain the same.
     REQUIRE(qu->size == 9);
-    REQUIRE(qu->capacity == 20);
+    REQUIRE(qu->capacity == 40);
+  }
+
+  SECTION("Push Ex Over Capacity")
+  {
+    size_t s = 4;
+    for (size_t k = 0; k < 18; k++) {
+      memcpy(qu->head, const_cast<char*>("world"), 5);
+      queue_push_ex(qu, 5);
+
+      // As it should over push the capacity, size should remain the same.
+      REQUIRE(qu->size == s + ((k + 1) * 5));
+    }
   }
 
   SECTION("Pop Empty Queue")