fix up free list allocator, add realloc

src/allocators.c

@@ -3,6 +3,7 @@
 FLAlloc FL_ALLOC = {0};
 Allocator ALLOC = {0};
 read_only FLNode FL_NIL_NODE = {0};
+read_only FreeList FL_NIL_LIST = {0};
 
 constexpr usize FL_GLOBAL_SIZE = MB(32);
 static b32 FL_GLOBAL_INIT = false;
@@ -209,30 +210,73 @@ static void GlobalFreeListInit(usize size)
 
 static rawptr FLMemAlloc(usize size)
 {
+	if (!FL_GLOBAL_INIT)
+	{
+		GlobalFreeListInit(FL_GLOBAL_SIZE);
+	}
+
 	return FreeListAlloc(&FL_ALLOC, size);
 }
 
 static rawptr FLMemAllocZeroed(usize size)
 {
-	rawptr ptr = FreeListAlloc(&FL_ALLOC, size);
+	rawptr ptr = FLMemAlloc(size);
 	MemZero(ptr, size);
 	return ptr;
 }
 
+static rawptr FLMemRealloc(rawptr old_ptr, usize size)
+{
+	return FreeListRealloc(&FL_ALLOC, old_ptr, size);
+}
+
 static void FLMemFree(rawptr ptr)
 {
 	FreeListFree(&FL_ALLOC, ptr);
 }
 
+/*
+ * Should be async safe given no other thread frees a pointer in the middle of a realloc
+ */
+static rawptr FreeListRealloc(FLAlloc *alloc, rawptr old_ptr, usize size)
+{
+	rawptr ptr = FreeListAlloc(alloc, size);
+	usize old_size = FreeListPtrSize(alloc, old_ptr);
+
+	MemCpy(ptr, old_ptr, old_size);
+
+	FreeListFree(alloc, old_ptr);
+
+	return ptr;
+}
+
+static usize FreeListPtrSize(FLAlloc *alloc, rawptr ptr)
+{
+	if (ptr == NULL) return 0;
+
+	usize size = 0;
+
+	TicketMutLock(&alloc->mut);
+
+	FreeList *list = _FreeListFindList(alloc, ptr);
+	if (list != NULL)
+	{
+		FLAllocHeader *header = cast(FLAllocHeader *, u8ptr(ptr) - sizeof(FLAllocHeader));
+		size = header->size + header->padding;
+	}
+
+	TicketMutUnlock(&alloc->mut);
+
+	return size;
+}
+
 static void FreeListInit(FLAlloc *alloc, usize size)
 {
-	alloc->lists = pMemAllocZeroed(sizeof(FreeList *) * 16);
+	alloc->list_head = pMemAllocZeroed(sizeof(FreeList));
-	alloc->list_count = 1;
-	alloc->list_capacity = 16;
 	alloc->nil = &FL_NIL_NODE;
 	alloc->grow_size = size;
 
-	_FreeListInit(&alloc->lists[0], size);
+	_FreeListInit(&alloc->list_head, size);
 
 	FreeListFreeAll(alloc);
 }
@@ -243,29 +287,30 @@ static void _FreeListInit(FreeList **alloc, usize size)
 	(*alloc)->data = (rawptr)(((uintptr)*alloc) + ((uintptr)sizeof(FreeList)));
 	(*alloc)->size = size;
 	(*alloc)->used = sizeof(FreeList);
+	(*alloc)->next = &FL_NIL_LIST;
 }
 
 static void FreeListFreeAll(FLAlloc *alloc)
 {
 	TicketMutLock(&alloc->mut);
 
-	if (alloc->list_count > 1)
+	FreeList *current = alloc->list_head->next;
+	FreeList *next = &FL_NIL_LIST;
+	while (current != &FL_NIL_LIST)
 	{
-		for (u32 i = 1; i < alloc->list_count; i++)
+		next = current->next;
-		{
+		pMemFree(current, current->size);
-			pMemFree(alloc->lists[i], alloc->lists[i]->size);
+		current = next;
-			alloc->lists[i] = NULL;
-		}
-
-		alloc->list_count = 1;
 	}
 
-	FLNode *node = (FLNode *)alloc->lists[0]->data;
+	current = alloc->list_head;
-	node->size = alloc->lists[0]->size;
+
+	FLNode *node = (FLNode *)current->data;
+	node->size = current->size;
 	node->next = &FL_NIL_NODE;
 
-	alloc->lists[0]->head = node;
+	current->head = node;
-	alloc->lists[0]->used = sizeof(FreeList);
+	current->used = sizeof(FreeList);
 
 	TicketMutUnlock(&alloc->mut);
 }
@@ -300,30 +345,35 @@ static FLNode *FreeListSearch(FreeList *alloc, usize size, usize alignment, usiz
 /*
  *	NOT SAFE TO CALL OUTSIDE OF FreeListAlloc
  */
-static void FreeListGrow(FLAlloc *alloc, usize alloc_size)
+static FreeList *FreeListGrow(FLAlloc *alloc, usize alloc_size)
 {
-	alloc->list_count += 1;
-	u32 i = alloc->list_count;
-	if (i >= alloc->list_capacity)
-	{
-		alloc->list_capacity += 16;
-		rawptr new_mem = pMemAlloc(sizeof(FreeList *) * alloc->list_capacity);
-		MemCpy(new_mem, alloc->lists, i);
-		pMemFree(alloc->lists, sizeof(FreeList *) * i);
-		alloc->lists = new_mem;
-	}
-
 	usize grow_size = alloc->grow_size;
 	if (alloc_size > grow_size)
 		grow_size += alloc_size;
 
-	_FreeListInit(&alloc->lists[i], grow_size);
+	FreeList *list = NULL;
 
-	FLNode *node = (FLNode *)alloc->lists[i]->data;
+	_FreeListInit(&list, grow_size);
-	node->size = alloc->lists[i]->size;
+
+	FLNode *node = (FLNode *)list->data;
+	node->size = list->size;
 	node->next = alloc->nil;
 
-	alloc->lists[i]->head = node;
+	list->head = node;
+
+	FreeList *current = alloc->list_head;
+	while (current != &FL_NIL_LIST)
+	{
+		if (current->next == &FL_NIL_LIST)
+		{
+			current->next = list;
+			break;
+		}
+
+		current = current->next;
+	}
+
+	return list;
 }
 
 static rawptr _FreeListAllocAlign(FreeList *alloc, usize size, usize alignment)
@@ -375,28 +425,25 @@ static rawptr FreeListAlloc(FLAlloc *alloc, usize size)
 
 static rawptr FreeListAllocAlign(FLAlloc *alloc, usize size, usize alignment)
 {
-	if (!FL_GLOBAL_INIT)
-	{
-		GlobalFreeListInit(FL_GLOBAL_SIZE);
-	}
-
 	TicketMutLock(&alloc->mut);
 
-	FreeList *fl = NULL;
+	FreeList *fl = &FL_NIL_LIST;
-	for (u32 i = 0; i < alloc->list_count; i++)
+	FreeList *current = alloc->list_head;
+	while (current != &FL_NIL_LIST)
 	{
-		usize remaining = alloc->lists[i]->size - alloc->lists[i]->used;
+		usize remaining = current->size - current->used;
 		if (size < remaining)
 		{
-			fl = alloc->lists[i];
+			fl = current;
 			break;
 		}
+
+		current = current->next;
 	}
 
-	if (fl == NULL)
+	if (fl == &FL_NIL_LIST)
 	{
-		FreeListGrow(alloc, size);
+		fl = FreeListGrow(alloc, size);
-		fl = alloc->lists[alloc->list_count-1];
 	}
 
 	rawptr ptr = _FreeListAllocAlign(fl, size, alignment);
@@ -406,6 +453,25 @@ static rawptr FreeListAllocAlign(FLAlloc *alloc, usize size, usize alignment)
 	return ptr;
 }
 
+static FreeList *_FreeListFindList(FLAlloc *alloc, rawptr ptr)
+{
+	FreeList *list = NULL;
+	FreeList *current = alloc->list_head;
+	while (current != &FL_NIL_LIST)
+	{
+		uintptr ptr_addr = uintptr(ptr);
+		uintptr start = uintptr(current->data);
+		uintptr end = uintptr(current->data) + uintptr(current->size);
+		if (ptr_addr >= start && ptr_addr < end)
+		{
+			list = current;
+			break;
+		}
+	}
+
+	return list;
+}
+
 static void _FreeListFree(FreeList *alloc, rawptr ptr)
 {
 	FLAllocHeader *header = cast(FLAllocHeader *, u8ptr(ptr) - sizeof(FLAllocHeader));
@@ -438,16 +504,10 @@ static void FreeListFree(FLAlloc *alloc, rawptr ptr)
 
 	TicketMutLock(&alloc->mut);
 
-	for (u32 i = 0; i < alloc->list_count; i++)
+	FreeList *list = _FreeListFindList(alloc, ptr);
+	if (list != NULL)
 	{
-		uintptr ptr_addr = uintptr(ptr);
+		_FreeListFree(list, ptr);
-		uintptr start = uintptr(alloc->lists[i]->data);
-		uintptr end = uintptr(alloc->lists[i]->data) + uintptr(alloc->lists[i]->size);
-		if (ptr_addr >= start && ptr_addr < end)
-		{
-			_FreeListFree(alloc->lists[i], ptr);
-			break;
-		}
 	}
 
 	TicketMutUnlock(&alloc->mut);

src/allocators.h

@@ -75,18 +75,17 @@ typedef struct FLNode
 
 typedef struct FreeList
 {
-	rawptr data;
+	rawptr 		data;
-	FLNode *head;
+	FLNode 	 *head;
-	usize  size;
+	usize  		size;
-	usize  used;
+	usize  		used;
+	struct FreeList *next;
 } FreeList;
 
 typedef struct FLAlloc
 {
-	FreeList 	**lists;
+	FreeList 	*list_head;
 	TicketMut mut;
-	u32      	list_count;
-	u32      	list_capacity;
 	FLNode   	*nil;
 	usize    	grow_size;
 } FLAlloc;
@@ -94,18 +93,22 @@ typedef struct FLAlloc
 static void GlobalFreeListInit(usize size);
 static rawptr FLMemAlloc(usize size);
 static rawptr FLMemAllocZeroed(usize size);
+static rawptr FLMemRealloc(rawptr old_ptr, usize size);
 static void FLMemFree(rawptr ptr);
-static void _FreeListInit(FreeList **alloc, usize size);
+static usize FreeListPtrSize(FLAlloc *alloc, rawptr ptr);
 static void FreeListInit(FLAlloc *alloc, usize size);
-static rawptr _FreeListAllocAlign(FreeList *alloc, usize size, usize alignment);
 static rawptr FreeListAllocAlign(FLAlloc *alloc, usize size, usize alignment);
 static rawptr FreeListAlloc(FLAlloc *alloc, usize size);
-static void _FreeListFree(FreeList *alloc, rawptr ptr);
 static void FreeListFree(FLAlloc *alloc, rawptr ptr);
 static void FreeListFreeAll(FLAlloc *alloc);
-static void FreeListGrow(FLAlloc *alloc, usize alloc_size);
+static FreeList *FreeListGrow(FLAlloc *alloc, usize alloc_size);
+static rawptr FreeListRealloc(FLAlloc *alloc, rawptr old_ptr, usize size);
 static FLNode *FreeListSearch(FreeList *alloc, usize size, usize alignment, usize *out_padding, FLNode **prev_node);
 static void FreeListCoalescence(FreeList *alloc, FLNode *prev_node, FLNode *free_node);
 static void FreeListRemove(FLNode **head, FLNode *prev_node, FLNode *del_node);
 static void FreeListInsert(FLNode **head, FLNode *prev_node, FLNode *new_node);
+static FreeList *_FreeListFindList(FLAlloc *alloc, rawptr ptr);
+static void _FreeListInit(FreeList **alloc, usize size);
+static rawptr _FreeListAllocAlign(FreeList *alloc, usize size, usize alignment);
+static void _FreeListFree(FreeList *alloc, rawptr ptr);