Add wpArrayRemoveSwapEnd

CHANGELOG.md

@@ -25,6 +25,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `wpPrngSplitmix64Init`, `wpPrngSplitmix64InitWithSeed`, `wpPrngSplitmix64`, `wpPrngSplitmix64InRange`, `wpPrngSplitmix64Choice`
 - `wpStr8Clear`
 - `wpArrayZero` to zero all elements in an array without setting the count to 0
+- `wpArrayRemoveSwapEnd` to remove an array element using its index and swap the last element in
 
 ### Changed
 

src/base/array/array.c

@@ -10,6 +10,7 @@
 #define arrayHeader(ARRAY) (WpArrayHeader *)(wpMiscUtilsOffsetPointer(ARRAY, (i64)sizeof(WpArrayHeader) * -1))
 
 wp_persist inline void  arrayValidate(const WpArray array, u64 item_size);
+wp_persist inline void *arrayGetItemWithOffset(const WpArray array, u64 offset);
 
 u64 arrayCount(WpArray array) {
 	wpDebugAssert(array != NULL, "`array` should not be NULL");
@@ -54,7 +55,7 @@ void *arrayGet(WpArray array, u64 index, u64 item_size) {
 	WpArrayHeader *header = arrayHeader(array);
 	wpRuntimeAssert(index < header->count, "`index` is out of bounds");
 
-	return wpMiscUtilsOffsetPointer(array, header->item_size * index);
+	return arrayGetItemWithOffset(array, header->item_size * index);
 }
 
 void arraySet(WpArray array, u64 index, void *value, u64 item_size) {
@@ -195,6 +196,22 @@ RETURN_ARRAY_COPY_ALLOC:
 	return output;
 }
 
+void arrayRemoveSwapEnd(WpArray array, u64 index, u64 item_size) {
+	wpRuntimeAssert(array != NULL, "`array` should not be NULL");
+	arrayValidate(array, item_size);
+
+	WpArrayHeader *header = arrayHeader(array);
+	if (header->count == 0 || index > header->count) { return; }
+
+	u64 last_item_index = header->count - 1;
+	void *cur_item      = arrayGetItemWithOffset(array, header->item_size * index);
+	void *last_item     = arrayGetItemWithOffset(array, header->item_size * last_item_index);
+
+	memcpy(cur_item, last_item, header->item_size);
+	memset(last_item, 0, header->item_size);
+	--(header->count);
+}
+
 void *arrayPop(WpArray array, u64 item_size) {
 	wpRuntimeAssert(array != NULL, "`array` should not be NULL");
 	arrayValidate(array, item_size);
@@ -203,7 +220,7 @@ void *arrayPop(WpArray array, u64 item_size) {
 	if (header->count == 0) { return NULL; }
 
 	u64 index = header->count - 1;
-	void *out = arrayGet(array, index, item_size);
+	void *out = arrayGetItemWithOffset(array, header->item_size * index);
 	--(header->count);
 	return out;
 }
@@ -283,3 +300,7 @@ wp_persist inline void arrayValidate(const WpArray array, u64 item_size) {
 	wpRuntimeAssert(WP_ARRAY_MAGIC == header->magic, "`array` is not a valid wapp array");
 	wpRuntimeAssert(item_size == header->item_size, "Invalid item type provided");
 }
+
+wp_persist inline void *arrayGetItemWithOffset(const WpArray array, u64 offset) {
+	return wpMiscUtilsOffsetPointer(array, offset);
+}

src/base/array/array.h

@@ -168,6 +168,7 @@ typedef enum WpArrayInitFlags {
 	                        (WpArray)SRC_ARRAY,                                                      \
 	                        FLAGS,                                                                   \
 	                        sizeof(TYPE)))
+#define wpArrayRemoveSwapEnd(TYPE, ARRAY, INDEX) arrayRemoveSwapEnd(ARRAY, INDEX, sizeof(TYPE))
 #define wpArrayZero(TYPE, ARRAY) (arrayZero((WpArray)ARRAY, sizeof(TYPE)))
 #define wpArrayClear(TYPE, ARRAY) (arrayClear((WpArray)ARRAY, sizeof(TYPE)))
 #define wpArrayCalcAllocSize(TYPE, CAPACITY) arrayCalcAllocSize(CAPACITY, sizeof(TYPE))
@@ -204,6 +205,7 @@ WpArray arrayExtendAlloc(const WpAllocator *allocator, WpArray dst, const WpArra
                          WpArrayInitFlags flags, u64 item_size);
 WpArray arrayCopyAlloc(const WpAllocator *allocator, WpArray dst, const WpArray src,
                        WpArrayInitFlags flags, u64 item_size);
+void    arrayRemoveSwapEnd(WpArray array, u64 index, u64 item_size);
 void   *arrayPop(WpArray array, u64 item_size);
 void    arrayZero(WpArray array, u64 item_size);
 void    arrayClear(WpArray array, u64 item_size);

tests/array/test_i32_array.c

@@ -245,6 +245,19 @@ WpTestFuncResult test_i32_array_copy_alloc(void) {
 	return wpTesterResult(result);
 }
 
+WpTestFuncResult test_i32_array_remove_swap_end(void) {
+	b8 result;
+
+	WpI32Array array = wpArray(i32, 0, 1, 2, 3, 4, 5, 6, 7, 8);
+	result = wpArrayCount(array) == 9 && array[4] == 4;
+
+	wpArrayRemoveSwapEnd(i32, array, 4);
+
+	result = result && wpArrayCount(array) == 8 && array[4] == 8;
+
+	return wpTesterResult(result);
+}
+
 WpTestFuncResult test_i32_array_pop(void) {
 	b8 result;
 

tests/array/test_i32_array.cc

@@ -261,6 +261,19 @@ WpTestFuncResult test_i32_array_clear(void) {
 	return wpTesterResult(result);
 }
 
+WpTestFuncResult test_i32_array_remove_swap_end(void) {
+	b8 result;
+
+	WpI32Array array = wpArray(i32, 0, 1, 2, 3, 4, 5, 6, 7, 8);
+	result = wpArrayCount(array) == 9 && array[4] == 4;
+
+	wpArrayRemoveSwapEnd(i32, array, 4);
+
+	result = result && wpArrayCount(array) == 8 && array[4] == 8;
+
+	return wpTesterResult(result);
+}
+
 WpTestFuncResult test_i32_array_pop(void) {
 	b8 result;
 

tests/array/test_i32_array.h

@@ -14,6 +14,7 @@ WpTestFuncResult test_i32_array_alloc_capacity(void);
 WpTestFuncResult test_i32_array_append_alloc(void);
 WpTestFuncResult test_i32_array_extend_alloc(void);
 WpTestFuncResult test_i32_array_copy_alloc(void);
+WpTestFuncResult test_i32_array_remove_swap_end(void);
 WpTestFuncResult test_i32_array_pop(void);
 WpTestFuncResult test_i32_array_clear(void);
 

tests/wapptest.c

@@ -44,6 +44,7 @@ int main(void) {
 		test_i32_array_append_alloc,
 		test_i32_array_extend_alloc,
 		test_i32_array_copy_alloc,
+		test_i32_array_remove_swap_end,
 		test_i32_array_pop,
 		test_i32_array_clear,
 		test_queue_push,

tests/wapptest.cc

@@ -44,6 +44,7 @@ int main(void) {
 		test_i32_array_append_alloc,
 		test_i32_array_extend_alloc,
 		test_i32_array_copy_alloc,
+		test_i32_array_remove_swap_end,
 		test_i32_array_pop,
 		test_i32_array_clear,
 		test_queue_push,