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raylib/src/rmem.h
Kevin Yonan 084fb31186 Removing '__RemoveNode' (#935) 
Replaced '__RemoveNode' as it was causing invalid memory accesses with regular doubly linked list deletion algorithm.
Replaced double pointer iterator in 'MemPoolAlloc' with single pointer iterator.
Fixed undefined variables errors in 'MemPoolFree' for the freelist bucket.
2019-08-08 10:00:23 +02:00

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/**********************************************************************************************
*
* rmem - raylib memory pool and objects pool
*
* A quick, efficient, and minimal free list and stack-based allocator
*
* PURPOSE:
* - A quicker, efficient memory allocator alternative to 'malloc' and friends.
* - Reduce the possibilities of memory leaks for beginner developers using Raylib.
* - Being able to flexibly range check memory if necessary.
*
* CONFIGURATION:
*
* #define RMEM_IMPLEMENTATION
* Generates the implementation of the library into the included file.
* If not defined, the library is in header only mode and can be included in other headers
* or source files without problems. But only ONE file should hold the implementation.
*
*
* LICENSE: zlib/libpng
*
* Copyright (c) 2019 Kevin 'Assyrianic' Yonan (@assyrianic) and reviewed by Ramon Santamaria (@raysan5)
*
* This software is provided "as-is", without any express or implied warranty. In no event
* will the authors be held liable for any damages arising from the use of this software.
*
* Permission is granted to anyone to use this software for any purpose, including commercial
* applications, and to alter it and redistribute it freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not claim that you
* wrote the original software. If you use this software in a product, an acknowledgment
* in the product documentation would be appreciated but is not required.
*
* 2. Altered source versions must be plainly marked as such, and must not be misrepresented
* as being the original software.
*
* 3. This notice may not be removed or altered from any source distribution.
*
**********************************************************************************************/
#ifndef RMEM_H
#define RMEM_H
#include <inttypes.h>
#include <stdbool.h>
//----------------------------------------------------------------------------------
// Defines and Macros
//----------------------------------------------------------------------------------
#if defined(_WIN32) && defined(BUILD_LIBTYPE_SHARED)
#define RMEMAPI __declspec(dllexport) // We are building library as a Win32 shared library (.dll)
#elif defined(_WIN32) && defined(USE_LIBTYPE_SHARED)
#define RMEMAPI __declspec(dllimport) // We are using library as a Win32 shared library (.dll)
#else
#define RMEMAPI // We are building or using library as a static library (or Linux shared library)
#endif
//----------------------------------------------------------------------------------
// Types and Structures Definition
//----------------------------------------------------------------------------------
// Memory Pool
typedef struct MemNode MemNode;
struct MemNode {
size_t size;
MemNode *next, *prev;
};
typedef struct AllocList {
MemNode *head, *tail;
size_t len, maxNodes;
bool autoDefrag : 1;
} AllocList;
typedef struct Stack {
uint8_t *mem, *base;
size_t size;
} Stack;
#define MEMPOOL_BUCKET_SIZE 8
#define MEMPOOL_BUCKET_BITS 3
typedef struct MemPool {
AllocList freeList;
Stack stack;
MemNode *buckets[MEMPOOL_BUCKET_SIZE];
} MemPool;
// Object Pool
typedef struct ObjPool {
Stack stack;
size_t objSize, freeBlocks;
} ObjPool;
#if defined(__cplusplus)
extern "C" { // Prevents name mangling of functions
#endif
//------------------------------------------------------------------------------------
// Functions Declaration - Memory Pool
//------------------------------------------------------------------------------------
RMEMAPI MemPool CreateMemPool(size_t bytes);
RMEMAPI MemPool CreateMemPoolFromBuffer(void *buf, size_t bytes);
RMEMAPI void DestroyMemPool(MemPool *mempool);
RMEMAPI void *MemPoolAlloc(MemPool *mempool, size_t bytes);
RMEMAPI void *MemPoolRealloc(MemPool *mempool, void *ptr, size_t bytes);
RMEMAPI void MemPoolFree(MemPool *mempool, void *ptr);
RMEMAPI void MemPoolCleanUp(MemPool *mempool, void **ptrref);
RMEMAPI bool MemPoolDefrag(MemPool *mempool);
RMEMAPI size_t GetMemPoolFreeMemory(const MemPool mempool);
RMEMAPI void ToggleMemPoolAutoDefrag(MemPool *mempool);
//------------------------------------------------------------------------------------
// Functions Declaration - Object Pool
//------------------------------------------------------------------------------------
RMEMAPI ObjPool CreateObjPool(size_t objsize, size_t len);
RMEMAPI ObjPool CreateObjPoolFromBuffer(void *buf, size_t objsize, size_t len);
RMEMAPI void DestroyObjPool(ObjPool *objpool);
RMEMAPI void *ObjPoolAlloc(ObjPool *objpool);
RMEMAPI void ObjPoolFree(ObjPool *objpool, void *ptr);
RMEMAPI void ObjPoolCleanUp(ObjPool *objpool, void **ptrref);
#ifdef __cplusplus
}
#endif
#endif // RMEM_H
/***********************************************************************************
*
* RMEM IMPLEMENTATION
*
************************************************************************************/
#if defined(RMEM_IMPLEMENTATION)
#include <stdio.h> // Required for:
#include <stdlib.h> // Required for:
#include <string.h> // Required for:
//----------------------------------------------------------------------------------
// Defines and Macros
//----------------------------------------------------------------------------------
// Make sure restrict type qualifier for pointers is defined
// NOTE: Not supported by C++, it is a C only keyword
#if defined(_WIN32) || defined(_WIN64) || defined(__CYGWIN__) || defined(_MSC_VER)
#ifndef restrict
#define restrict __restrict
#endif
#endif
//----------------------------------------------------------------------------------
// Global Variables Definition
//----------------------------------------------------------------------------------
// ...
//----------------------------------------------------------------------------------
// Module specific Functions Declaration
//----------------------------------------------------------------------------------
static inline size_t __AlignSize(const size_t size, const size_t align)
{
return (size + (align - 1)) & -align;
}
//----------------------------------------------------------------------------------
// Module Functions Definition - Memory Pool
//----------------------------------------------------------------------------------
MemPool CreateMemPool(const size_t size)
{
MemPool mempool = { 0 };
if (size == 0UL) return mempool;
else
{
// Align the mempool size to at least the size of an alloc node.
mempool.stack.size = size;
mempool.stack.mem = malloc(mempool.stack.size*sizeof *mempool.stack.mem);
if (mempool.stack.mem==NULL)
{
mempool.stack.size = 0UL;
return mempool;
}
else
{
mempool.stack.base = mempool.stack.mem + mempool.stack.size;
return mempool;
}
}
}
MemPool CreateMemPoolFromBuffer(void *buf, const size_t size)
{
MemPool mempool = { 0 };
if ((size == 0UL) || (buf == NULL) || (size <= sizeof(MemNode))) return mempool;
else
{
mempool.stack.size = size;
mempool.stack.mem = buf;
mempool.stack.base = mempool.stack.mem + mempool.stack.size;
return mempool;
}
}
void DestroyMemPool(MemPool *const mempool)
{
if ((mempool == NULL) || (mempool->stack.mem == NULL)) return;
else
{
free(mempool->stack.mem);
*mempool = (MemPool){ 0 };
}
}
void *MemPoolAlloc(MemPool *const mempool, const size_t size)
{
if ((mempool == NULL) || (size == 0UL) || (size > mempool->stack.size)) return NULL;
else
{
MemNode *new_mem = NULL;
const size_t ALLOC_SIZE = __AlignSize(size + sizeof *new_mem, sizeof(intptr_t));
const size_t BUCKET_INDEX = (ALLOC_SIZE >> MEMPOOL_BUCKET_BITS) - 1;
// If the size is small enough, let's check if our buckets has a fitting memory block.
if (BUCKET_INDEX < MEMPOOL_BUCKET_SIZE && mempool->buckets[BUCKET_INDEX] != NULL && mempool->buckets[BUCKET_INDEX]->size >= ALLOC_SIZE)
{
new_mem = mempool->buckets[BUCKET_INDEX];
mempool->buckets[BUCKET_INDEX] = mempool->buckets[BUCKET_INDEX]->next;
if( mempool->buckets[BUCKET_INDEX] != NULL )
mempool->buckets[BUCKET_INDEX]->prev = NULL;
}
else if (mempool->freeList.head != NULL)
{
const size_t MEM_SPLIT_THRESHOLD = 16;
// If the freelist is valid, let's allocate FROM the freelist then!
for (MemNode *inode = mempool->freeList.head; inode != NULL; inode = inode->next)
{
if (inode->size < ALLOC_SIZE) continue;
else if (inode->size <= (ALLOC_SIZE + MEM_SPLIT_THRESHOLD))
{
// Close in size - reduce fragmentation by not splitting.
new_mem = inode;
(inode->prev != NULL)? (inode->prev->next = inode->next) : (mempool->freeList.head = inode->next);
(inode->next != NULL)? (inode->next->prev = inode->prev) : (mempool->freeList.tail = inode->prev);
if (mempool->freeList.head != NULL) mempool->freeList.head->prev = NULL;
else mempool->freeList.tail = NULL;
if (mempool->freeList.tail != NULL) mempool->freeList.tail->next = NULL;
mempool->freeList.len--;
break;
}
else
{
// Split the memory chunk.
new_mem = (MemNode *)((uint8_t *)inode + (inode->size - ALLOC_SIZE));
inode->size -= ALLOC_SIZE;
new_mem->size = ALLOC_SIZE;
break;
}
}
}
if (new_mem == NULL)
{
// not enough memory to support the size!
if ((mempool->stack.base - ALLOC_SIZE) < mempool->stack.mem) return NULL;
else
{
// Couldn't allocate from a freelist, allocate from available mempool.
// Subtract allocation size from the mempool.
mempool->stack.base -= ALLOC_SIZE;
// Use the available mempool space as the new node.
new_mem = (MemNode *)mempool->stack.base;
new_mem->size = ALLOC_SIZE;
}
}
// Visual of the allocation block.
// --------------
// | mem size | lowest addr of block
// | next node | 12 byte (32-bit) header
// | prev node | 24 byte (64-bit) header
// --------------
// | alloc'd |
// | memory |
// | space | highest addr of block
// --------------
new_mem->next = new_mem->prev = NULL;
uint8_t *const final_mem = (uint8_t *)new_mem + sizeof *new_mem;
memset(final_mem, 0, new_mem->size - sizeof *new_mem);
return final_mem;
}
}
void *MemPoolRealloc(MemPool *const restrict mempool, void *ptr, const size_t size)
{
if ((mempool == NULL) || (size > mempool->stack.size)) return NULL;
// NULL ptr should make this work like regular Allocation.
else if (ptr == NULL) return MemPoolAlloc(mempool, size);
else if ((uintptr_t)ptr - sizeof(MemNode) < (uintptr_t)mempool->stack.mem) return NULL;
else
{
MemNode *const node = (MemNode *)((uint8_t *)ptr - sizeof *node);
const size_t NODE_SIZE = sizeof *node;
uint8_t *const resized_block = MemPoolAlloc(mempool, size);
if (resized_block == NULL) return NULL;
else
{
MemNode *const resized = (MemNode *)(resized_block - sizeof *resized);
memmove(resized_block, ptr, (node->size > resized->size)? (resized->size - NODE_SIZE) : (node->size - NODE_SIZE));
MemPoolFree(mempool, ptr);
return resized_block;
}
}
}
void MemPoolFree(MemPool *const restrict mempool, void *ptr)
{
if ((mempool == NULL) || (ptr == NULL) || ((uintptr_t)ptr - sizeof(MemNode) < (uintptr_t)mempool->stack.mem)) return;
else
{
// Behind the actual pointer data is the allocation info.
MemNode *const mem_node = (MemNode *)((uint8_t *)ptr - sizeof *mem_node);
const size_t BUCKET_INDEX = (mem_node->size >> MEMPOOL_BUCKET_BITS) - 1;
// Make sure the pointer data is valid.
if (((uintptr_t)mem_node < (uintptr_t)mempool->stack.base) ||
(((uintptr_t)mem_node - (uintptr_t)mempool->stack.mem) > mempool->stack.size) ||
(mem_node->size == 0UL) ||
(mem_node->size > mempool->stack.size)) return;
// If the mem_node is right at the stack base ptr, then add it to the stack.
else if ((uintptr_t)mem_node == (uintptr_t)mempool->stack.base)
{
mempool->stack.base += mem_node->size;
}
// attempted stack merge failed, try to place it into the memnode buckets
else if (BUCKET_INDEX < MEMPOOL_BUCKET_SIZE)
{
if (mempool->buckets[BUCKET_INDEX] == NULL) mempool->buckets[BUCKET_INDEX] = mem_node;
else
{
for (MemNode *n = mempool->buckets[BUCKET_INDEX]; n != NULL; n = n->next) if( n==mem_node ) return;
mempool->buckets[BUCKET_INDEX]->prev = mem_node;
mem_node->next = mempool->buckets[BUCKET_INDEX];
mempool->buckets[BUCKET_INDEX] = mem_node;
}
}
// Otherwise, we add it to the free list.
// We also check if the freelist already has the pointer so we can prevent double frees.
else /*if ((mempool->freeList.len == 0UL) || ((uintptr_t)mempool->freeList.head >= (uintptr_t)mempool->stack.mem && (uintptr_t)mempool->freeList.head - (uintptr_t)mempool->stack.mem < mempool->stack.size))*/
{
for (MemNode *n = mempool->freeList.head; n != NULL; n = n->next) if (n == mem_node) return;
// This code insertion sorts where largest size is last.
if (mempool->freeList.head == NULL)
{
mempool->freeList.head = mempool->freeList.tail = mem_node;
mempool->freeList.len++;
}
else if (mempool->freeList.head->size >= mem_node->size)
{
mem_node->next = mempool->freeList.head;
mem_node->next->prev = mem_node;
mempool->freeList.head = mem_node;
mempool->freeList.len++;
}
else //if (mempool->freeList.tail->size <= mem_node->size)
{
mem_node->prev = mempool->freeList.tail;
mempool->freeList.tail->next = mem_node;
mempool->freeList.tail = mem_node;
mempool->freeList.len++;
}
if (mempool->freeList.autoDefrag && (mempool->freeList.maxNodes != 0UL) && (mempool->freeList.len > mempool->freeList.maxNodes)) MemPoolDefrag(mempool);
}
}
}
void MemPoolCleanUp(MemPool *const restrict mempool, void **ptrref)
{
if ((mempool == NULL) || (ptrref == NULL) || (*ptrref == NULL)) return;
else
{
MemPoolFree(mempool, *ptrref);
*ptrref = NULL;
}
}
size_t GetMemPoolFreeMemory(const MemPool mempool)
{
size_t total_remaining = (uintptr_t)mempool.stack.base - (uintptr_t)mempool.stack.mem;
for (MemNode *n=mempool.freeList.head; n != NULL; n = n->next) total_remaining += n->size;
for (size_t i=0; i<MEMPOOL_BUCKET_SIZE; i++) for (MemNode *n = mempool.buckets[i]; n != NULL; n = n->next) total_remaining += n->size;
return total_remaining;
}
bool MemPoolDefrag(MemPool *const mempool)
{
if (mempool == NULL) return false;
else
{
// If the memory pool has been entirely released, fully defrag it.
if (mempool->stack.size == GetMemPoolFreeMemory(*mempool))
{
mempool->freeList.head = mempool->freeList.tail = NULL;
mempool->freeList.len = 0;
for (size_t i = 0; i < MEMPOOL_BUCKET_SIZE; i++) mempool->buckets[i] = NULL;
mempool->stack.base = mempool->stack.mem + mempool->stack.size;
return true;
}
else
{
for (size_t i=0; i<MEMPOOL_BUCKET_SIZE; i++)
{
while (mempool->buckets[i] != NULL)
{
if ((uintptr_t)mempool->buckets[i] == (uintptr_t)mempool->stack.base)
{
mempool->stack.base += mempool->buckets[i]->size;
mempool->buckets[i]->size = 0;
mempool->buckets[i] = mempool->buckets[i]->next;
if (mempool->buckets[i] != NULL) mempool->buckets[i]->prev = NULL;
}
else break;
}
}
const size_t PRE_DEFRAG_LEN = mempool->freeList.len;
MemNode **node = &mempool->freeList.head;
while (*node != NULL)
{
if ((uintptr_t)*node == (uintptr_t)mempool->stack.base)
{
// If node is right at the stack, merge it back into the stack.
mempool->stack.base += (*node)->size;
(*node)->size = 0UL;
((*node)->prev != NULL)? ((*node)->prev->next = (*node)->next) : (mempool->freeList.head = (*node)->next);
((*node)->next != NULL)? ((*node)->next->prev = (*node)->prev) : (mempool->freeList.tail = (*node)->prev);
if (mempool->freeList.head != NULL) mempool->freeList.head->prev = NULL;
else mempool->freeList.tail = NULL;
if (mempool->freeList.tail != NULL) mempool->freeList.tail->next = NULL;
mempool->freeList.len--;
node = &mempool->freeList.head;
}
else if (((uintptr_t)*node + (*node)->size) == (uintptr_t)(*node)->next)
{
// Next node is at a higher address.
(*node)->size += (*node)->next->size;
(*node)->next->size = 0UL;
// <-[P Curr N]-> <-[P Next N]-> <-[P NextNext N]->
//
// |--------------------|
// <-[P Curr N]-> <-[P Next N]-> [P NextNext N]->
if ((*node)->next->next != NULL) (*node)->next->next->prev = *node;
// <-[P Curr N]-> <-[P NextNext N]->
(*node)->next = (*node)->next->next;
mempool->freeList.len--;
node = &mempool->freeList.head;
}
else if ((((uintptr_t)*node + (*node)->size) == (uintptr_t)(*node)->prev) && ((*node)->prev->prev != NULL))
{
// Prev node is at a higher address.
(*node)->size += (*node)->prev->size;
(*node)->prev->size = 0UL;
// <-[P PrevPrev N]-> <-[P Prev N]-> <-[P Curr N]->
//
// |--------------------|
// <-[P PrevPrev N] <-[P Prev N]-> <-[P Curr N]->
(*node)->prev->prev->next = *node;
// <-[P PrevPrev N]-> <-[P Curr N]->
(*node)->prev = (*node)->prev->prev;
mempool->freeList.len--;
node = &mempool->freeList.head;
}
else if ((*node)->prev != NULL && (*node)->next != NULL && (uintptr_t)*node - (*node)->next->size == (uintptr_t)(*node)->next)
{
// Next node is at a lower address.
(*node)->next->size += (*node)->size;
(*node)->size = 0UL;
(*node)->next->prev = (*node)->prev;
(*node)->prev->next = (*node)->next;
*node = (*node)->next;
mempool->freeList.len--;
node = &mempool->freeList.head;
}
else if ((*node)->prev != NULL && (*node)->next != NULL && (uintptr_t)*node - (*node)->prev->size == (uintptr_t)(*node)->prev)
{
// Prev node is at a lower address.
(*node)->prev->size += (*node)->size;
(*node)->size = 0UL;
(*node)->next->prev = (*node)->prev;
(*node)->prev->next = (*node)->next;
*node = (*node)->prev;
mempool->freeList.len--;
node = &mempool->freeList.head;
}
else
{
node = &(*node)->next;
}
}
return PRE_DEFRAG_LEN > mempool->freeList.len;
}
}
}
void ToggleMemPoolAutoDefrag(MemPool *const mempool)
{
if (mempool == NULL) return;
else mempool->freeList.autoDefrag ^= true;
}
//----------------------------------------------------------------------------------
// Module Functions Definition - Object Pool
//----------------------------------------------------------------------------------
union ObjInfo {
uint8_t *const byte;
size_t *const index;
};
ObjPool CreateObjPool(const size_t objsize, const size_t len)
{
ObjPool objpool = { 0 };
if ((len == 0UL) || (objsize == 0UL)) return objpool;
else
{
objpool.objSize = __AlignSize(objsize, sizeof(size_t));
objpool.stack.size = objpool.freeBlocks = len;
objpool.stack.mem = calloc(objpool.stack.size, objpool.objSize);
if (objpool.stack.mem == NULL)
{
objpool.stack.size = 0UL;
return objpool;
}
else
{
for (size_t i=0; i<objpool.freeBlocks; i++)
{
union ObjInfo block = { .byte = &objpool.stack.mem[i*objpool.objSize] };
*block.index = i + 1;
}
objpool.stack.base = objpool.stack.mem;
return objpool;
}
}
}
ObjPool CreateObjPoolFromBuffer(void *const buf, const size_t objsize, const size_t len)
{
ObjPool objpool = { 0 };
// If the object size isn't large enough to align to a size_t, then we can't use it.
if ((buf == NULL) || (len == 0UL) || (objsize < sizeof(size_t)) || (objsize*len != __AlignSize(objsize, sizeof(size_t))*len)) return objpool;
else
{
objpool.objSize = __AlignSize(objsize, sizeof(size_t));
objpool.stack.size = objpool.freeBlocks = len;
objpool.stack.mem = buf;
for (size_t i=0; i<objpool.freeBlocks; i++)
{
union ObjInfo block = { .byte = &objpool.stack.mem[i*objpool.objSize] };
*block.index = i + 1;
}
objpool.stack.base = objpool.stack.mem;
return objpool;
}
}
void DestroyObjPool(ObjPool *const objpool)
{
if ((objpool == NULL) || (objpool->stack.mem == NULL)) return;
else
{
free(objpool->stack.mem);
*objpool = (ObjPool){0};
}
}
void *ObjPoolAlloc(ObjPool *const objpool)
{
if (objpool == NULL) return NULL;
else
{
if (objpool->freeBlocks > 0UL)
{
// For first allocation, head points to the very first index.
// Head = &pool[0];
// ret = Head == ret = &pool[0];
union ObjInfo ret = { .byte = objpool->stack.base };
objpool->freeBlocks--;
// after allocating, we set head to the address of the index that *Head holds.
// Head = &pool[*Head * pool.objsize];
objpool->stack.base = (objpool->freeBlocks != 0UL)? objpool->stack.mem + (*ret.index*objpool->objSize) : NULL;
memset(ret.byte, 0, objpool->objSize);
return ret.byte;
}
else return NULL;
}
}
void ObjPoolFree(ObjPool *const restrict objpool, void *ptr)
{
union ObjInfo p = { .byte = ptr };
if ((objpool == NULL) || (ptr == NULL) || (p.byte < objpool->stack.mem) || (p.byte > objpool->stack.mem + objpool->stack.size*objpool->objSize)) return;
else
{
// When we free our pointer, we recycle the pointer space to store the previous index and then we push it as our new head.
// *p = index of Head in relation to the buffer;
// Head = p;
*p.index = (objpool->stack.base != NULL)? (objpool->stack.base - objpool->stack.mem)/objpool->objSize : objpool->stack.size;
objpool->stack.base = p.byte;
objpool->freeBlocks++;
}
}
void ObjPoolCleanUp(ObjPool *const restrict objpool, void **ptrref)
{
if ((objpool == NULL) || (ptrref == NULL) || (*ptrref == NULL)) return;
else
{
ObjPoolFree(objpool, *ptrref);
*ptrref = NULL;
}
}
#endif // RMEM_IMPLEMENTATION
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