From 4a546e7b2f471157c6f479df1ef687864fcbd89e Mon Sep 17 00:00:00 2001

From: Eric Haszlakiewicz <erh+git@nimenees.com>

Date: Sun, 24 May 2020 03:53:32 +0000

Subject: [PATCH] In arraylist, use malloc instead of calloc, avoid clearing

 with memeset until we really need to, and micro-optimize array_list_add().

---

 arraylist.c | 29 +++++++++++++++++++++++++----

 1 file changed, 25 insertions(+), 4 deletions(-)

diff --git a/arraylist.c b/arraylist.c

index e5524aca75..3e7bfa8950 100644

--- a/arraylist.c

+++ b/arraylist.c

@@ -40,13 +40,13 @@ struct array_list *array_list_new(array_list_free_fn *free_fn)

 {

 	struct array_list *arr;

-	arr = (struct array_list *)calloc(1, sizeof(struct array_list));

+	arr = (struct array_list *)malloc(sizeof(struct array_list));

 	if (!arr)

 		return NULL;

 	arr->size = ARRAY_LIST_DEFAULT_SIZE;

 	arr->length = 0;

 	arr->free_fn = free_fn;

-	if (!(arr->array = (void **)calloc(arr->size, sizeof(void *))))

+	if (!(arr->array = (void **)malloc(arr->size * sizeof(void *))))

 	{

 		free(arr);

 		return NULL;

@@ -92,11 +92,11 @@ static int array_list_expand_internal(struct array_list *arr, size_t max)

 	if (!(t = realloc(arr->array, new_size * sizeof(void *))))

 		return -1;

 	arr->array = (void **)t;

-	(void)memset(arr->array + arr->size, 0, (new_size - arr->size) * sizeof(void *));

 	arr->size = new_size;

 	return 0;

 }

+//static inline int _array_list_put_idx(struct array_list *arr, size_t idx, void *data)

 int array_list_put_idx(struct array_list *arr, size_t idx, void *data)

 {

 	if (idx > SIZE_T_MAX - 1)

@@ -106,6 +106,17 @@ int array_list_put_idx(struct array_list *arr, size_t idx, void *data)

 	if (idx < arr->length && arr->array[idx])

 		arr->free_fn(arr->array[idx]);

 	arr->array[idx] = data;

+	if (idx > arr->length)

+	{

+		/* Zero out the arraylist slots in between the old length

+		   and the newly added entry so we know those entries are

+		   empty.

+		   e.g. when setting array[7] in an array that used to be 

+		   only 5 elements longs, array[5] and array[6] need to be

+		   set to 0.

+		 */

+		memset(arr->array + arr->length, 0, (idx - arr->length) * sizeof(void *));

+	}

 	if (arr->length <= idx)

 		arr->length = idx + 1;

 	return 0;

@@ -113,7 +124,17 @@ int array_list_put_idx(struct array_list *arr, size_t idx, void *data)

 int array_list_add(struct array_list *arr, void *data)

 {

-	return array_list_put_idx(arr, arr->length, data);

+	/* Repeat some of array_list_put_idx() so we can skip several

+	   checks that we know are unnecessary when appending at the end

+	 */

+	size_t idx = arr->length;

+	if (idx > SIZE_T_MAX - 1)

+		return -1;

+	if (array_list_expand_internal(arr, idx + 1))

+		return -1;

+	arr->array[idx] = data;

+	arr->length++;

+	return 0;

 }

 void array_list_sort(struct array_list *arr, int (*compar)(const void *, const void *))