REMOVED: rmem library from raylib sources

Moved to own repo: https://github.com/raylib-extras/rmem

src/rmem.h

@@ -1,788 +0,0 @@
-/**********************************************************************************************
-*
-*   rmem v1.3 - raylib memory pool and objects pool
-*
-*   A quick, efficient, and minimal free list and arena-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.
-*
-*   DOCUMENTATION:
-*
-*       raylib Wiki: https://github.com/raysan5/raylib/wiki/raylib-memory-pool
-*       Usage example with raylib: https://github.com/raysan5/raylib/issues/1329
-*
-*   CHANGELOG:
-*
-*       v1.0: First version
-*       v1.1: Bug patches for the mempool and addition of object pool
-*       v1.2: Addition of bidirectional arena
-*       v1.3: Several changes:
-*         Pptimizations of allocators
-*         Renamed 'Stack' to 'Arena'
-*         Replaced certain define constants with an anonymous enum
-*         Refactored MemPool to no longer require active or deferred defragging
-*
-*
-*   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
-
-#define RMEM_VERSION    "v1.3"    // changelog at bottom of header.
-
-//----------------------------------------------------------------------------------
-// Types and Structures Definition
-//----------------------------------------------------------------------------------
-
-enum {
-    MEMPOOL_BUCKET_SIZE = 8,
-    MEMPOOL_BUCKET_BITS = (sizeof(uintptr_t) >> 1) + 1,
-    MEM_SPLIT_THRESHOLD = sizeof(uintptr_t) * 4
-};
-
-// Memory pool node
-typedef struct MemNode MemNode;
-struct MemNode {
-    size_t size;
-    MemNode *next, *prev;
-};
-
-// Freelist implementation
-typedef struct AllocList {
-    MemNode *head, *tail;
-    size_t len;
-} AllocList;
-
-// Arena allocator
-typedef struct Arena {
-    uintptr_t mem, offs;
-    size_t size;
-} Arena;
-
-// Memory pool
-typedef struct MemPool {
-    AllocList large, buckets[MEMPOOL_BUCKET_SIZE];
-    Arena arena;
-} MemPool;
-
-// Object pool
-typedef struct ObjPool {
-    uintptr_t mem, offs;
-    size_t objSize, freeBlocks, memSize;
-} ObjPool;
-
-// Double-ended stack (aka Deque)
-typedef struct BiStack {
-    uintptr_t mem, front, back;
-    size_t size;
-} BiStack;
-
-
-#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 void MemPoolReset(MemPool *mempool);
-RMEMAPI size_t GetMemPoolFreeMemory(const 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);
-
-//------------------------------------------------------------------------------------
-// Functions Declaration - Double-Ended Stack
-//------------------------------------------------------------------------------------
-RMEMAPI BiStack CreateBiStack(size_t len);
-RMEMAPI BiStack CreateBiStackFromBuffer(void *buf, size_t len);
-RMEMAPI void DestroyBiStack(BiStack *destack);
-
-RMEMAPI void *BiStackAllocFront(BiStack *destack, size_t len);
-RMEMAPI void *BiStackAllocBack(BiStack *destack, size_t len);
-
-RMEMAPI void BiStackResetFront(BiStack *destack);
-RMEMAPI void BiStackResetBack(BiStack *destack);
-RMEMAPI void BiStackResetAll(BiStack *destack);
-
-RMEMAPI intptr_t BiStackMargins(BiStack destack);
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif // RMEM_H
-
-/***********************************************************************************
-*
-*   RMEM IMPLEMENTATION
-*
-************************************************************************************/
-
-#if defined(RMEM_IMPLEMENTATION)
-
-#include <stdlib.h>         // Required for: malloc(), calloc(), free()
-#include <string.h>         // Required for: memset(), memcpy(), memmove()
-
-//----------------------------------------------------------------------------------
-// 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;
-}
-
-static MemNode *__SplitMemNode(MemNode *const node, const size_t bytes)
-{
-    uintptr_t n = ( uintptr_t )node;
-    MemNode *const r = ( MemNode* )(n + (node->size - bytes));
-    node->size -= bytes;
-    r->size = bytes;
-
-    return r;
-}
-
-static void __InsertMemNodeBefore(AllocList *const list, MemNode *const insert, MemNode *const curr)
-{
-    insert->next = curr;
-
-    if (curr->prev==NULL) list->head = insert;
-    else
-    {
-        insert->prev = curr->prev;
-        curr->prev->next = insert;
-    }
-
-    curr->prev = insert;
-}
-
-static void __ReplaceMemNode(MemNode *const old, MemNode *const replace)
-{
-    replace->prev = old->prev;
-    replace->next = old->next;
-
-    if (old->prev != NULL) old->prev->next = replace;
-    if (old->next != NULL) old->next->prev = replace;
-}
-
-
-static MemNode *__RemoveMemNode(AllocList *const list, MemNode *const node)
-{
-    if (node->prev != NULL) node->prev->next = node->next;
-    else
-    {
-        list->head = node->next;
-        if (list->head != NULL) list->head->prev = NULL;
-        else list->tail = NULL;
-    }
-
-    if (node->next != NULL) node->next->prev = node->prev;
-    else
-    {
-        list->tail = node->prev;
-        if (list->tail != NULL) list->tail->next = NULL;
-        else list->head = NULL;
-    }
-
-    list->len--;
-
-    return node;
-}
-
-static MemNode *__FindMemNode(AllocList *const list, const size_t bytes)
-{
-    for (MemNode *node = list->head; node != NULL; node = node->next)
-    {
-        if (node->size < bytes) continue;
-
-        // Close in size - reduce fragmentation by not splitting
-        else if (node->size <= bytes + MEM_SPLIT_THRESHOLD) return __RemoveMemNode(list, node);
-        else return __SplitMemNode(node, bytes);
-    }
-
-    return NULL;
-}
-
-static void __InsertMemNode(MemPool *const mempool, AllocList *const list, MemNode *const node, const bool is_bucket)
-{
-    if (list->head == NULL)
-    {
-        list->head = node;
-        list->len++;
-    }
-    else
-    {
-        for (MemNode *iter = list->head; iter != NULL; iter = iter->next)
-        {
-            if ((uintptr_t)iter == mempool->arena.offs)
-            {
-                mempool->arena.offs += iter->size;
-                __RemoveMemNode(list, iter);
-                iter = list->head;
-
-                if (iter == NULL)
-                {
-                    list->head = node;
-                    return;
-                }
-            }
-
-            const uintptr_t inode = (uintptr_t)node;
-            const uintptr_t iiter = (uintptr_t)iter;
-            const uintptr_t iter_end = iiter + iter->size;
-            const uintptr_t node_end = inode + node->size;
-
-            if (iter == node) return;
-            else if (iter < node)
-            {
-                // node was coalesced prior.
-                if (iter_end > inode) return;
-                else if ((iter_end == inode) && !is_bucket)
-                {
-                    // if we can coalesce, do so.
-                    iter->size += node->size;
-
-                    return;
-                }
-                else if (iter->next == NULL)
-                {
-                    // we reached the end of the free list -> append the node
-                    iter->next = node;
-                    node->prev = iter;
-                    list->len++;
-
-                    return;
-                }
-            }
-            else if (iter > node)
-            {
-                // Address sort, lowest to highest aka ascending order.
-                if (iiter < node_end) return;
-                else if ((iter == list->head) && !is_bucket)
-                {
-                    if (iter_end == inode) iter->size += node->size;
-                    else if (node_end == iiter)
-                    {
-                        node->size += list->head->size;
-                        node->next = list->head->next;
-                        node->prev = NULL;
-                        list->head = node;
-                    }
-                    else
-                    {
-                        node->next = iter;
-                        node->prev = NULL;
-                        iter->prev = node;
-                        list->head = node;
-                        list->len++;
-                    }
-
-                    return;
-                }
-                else if ((iter_end == inode) && !is_bucket)
-                {
-                    // if we can coalesce, do so.
-                    iter->size += node->size;
-                    return;
-                }
-                else
-                {
-                    __InsertMemNodeBefore(list, node, iter);
-                    list->len++;
-                    return;
-                }
-            }
-        }
-    }
-}
-
-//----------------------------------------------------------------------------------
-// Module Functions Definition - Memory Pool
-//----------------------------------------------------------------------------------
-
-MemPool CreateMemPool(const size_t size)
-{
-    MemPool mempool = { 0 };
-
-    if (size == 0) return mempool;
-    else
-    {
-        // Align the mempool size to at least the size of an alloc node.
-        uint8_t *const restrict buf = malloc(size*sizeof *buf);
-
-        if (buf==NULL) return mempool;
-        else
-        {
-            mempool.arena.size = size;
-            mempool.arena.mem = (uintptr_t)buf;
-            mempool.arena.offs = mempool.arena.mem + mempool.arena.size;
-
-            return mempool;
-        }
-    }
-}
-
-MemPool CreateMemPoolFromBuffer(void *const restrict buf, const size_t size)
-{
-    MemPool mempool = { 0 };
-
-    if ((size == 0) || (buf == NULL) || (size <= sizeof(MemNode))) return mempool;
-    else
-    {
-        mempool.arena.size = size;
-        mempool.arena.mem = (uintptr_t)buf;
-        mempool.arena.offs = mempool.arena.mem + mempool.arena.size;
-
-        return mempool;
-    }
-}
-
-void DestroyMemPool(MemPool *const restrict mempool)
-{
-    if (mempool->arena.mem == 0) return;
-    else
-    {
-        void *const restrict ptr = (void *)mempool->arena.mem;
-        free(ptr);
-        *mempool = (MemPool){ 0 };
-    }
-}
-
-void *MemPoolAlloc(MemPool *const mempool, const size_t size)
-{
-    if ((size == 0) || (size > mempool->arena.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_SLOT = (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_SLOT < MEMPOOL_BUCKET_SIZE)
-        {
-            new_mem = __FindMemNode(&mempool->buckets[BUCKET_SLOT], ALLOC_SIZE);
-        }
-        else if (mempool->large.head != NULL)
-        {
-            new_mem = __FindMemNode(&mempool->large, ALLOC_SIZE);
-        }
-
-        if (new_mem == NULL)
-        {
-            // not enough memory to support the size!
-            if ((mempool->arena.offs - ALLOC_SIZE) < mempool->arena.mem) return NULL;
-            else
-            {
-                // Couldn't allocate from a freelist, allocate from available mempool.
-                // Subtract allocation size from the mempool.
-                mempool->arena.offs -= ALLOC_SIZE;
-
-                // Use the available mempool space as the new node.
-                new_mem = ( MemNode* )mempool->arena.offs;
-                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 restrict final_mem = (uint8_t *)new_mem + sizeof *new_mem;
-
-        return memset(final_mem, 0, new_mem->size - sizeof *new_mem);
-    }
-}
-
-void *MemPoolRealloc(MemPool *const restrict mempool, void *const ptr, const size_t size)
-{
-    if (size > mempool->arena.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) < mempool->arena.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 *const ptr)
-{
-    const uintptr_t p = (uintptr_t)ptr;
-
-    if ((ptr == NULL) || (p - sizeof(MemNode) < mempool->arena.mem)) return;
-    else
-    {
-        // Behind the actual pointer data is the allocation info.
-        const uintptr_t block = p - sizeof(MemNode);
-        MemNode *const mem_node = ( MemNode* )block;
-        const size_t BUCKET_SLOT = (mem_node->size >> MEMPOOL_BUCKET_BITS) - 1;
-
-        // Make sure the pointer data is valid.
-        if ((block < mempool->arena.offs) ||
-            ((block - mempool->arena.mem) > mempool->arena.size) ||
-            (mem_node->size == 0) ||
-            (mem_node->size > mempool->arena.size)) return;
-        // If the mem_node is right at the arena offs, then merge it back to the arena.
-        else if (block == mempool->arena.offs)
-        {
-            mempool->arena.offs += mem_node->size;
-        }
-        else
-        {
-            // try to place it into bucket or large freelist.
-            struct AllocList *const l = (BUCKET_SLOT < MEMPOOL_BUCKET_SIZE) ? &mempool->buckets[BUCKET_SLOT] : &mempool->large;
-            __InsertMemNode(mempool, l, mem_node, (BUCKET_SLOT < MEMPOOL_BUCKET_SIZE));
-        }
-    }
-}
-
-void MemPoolCleanUp(MemPool *const restrict mempool, void **const ptrref)
-{
-    if ((ptrref == NULL) || (*ptrref == NULL)) return;
-    else
-    {
-        MemPoolFree(mempool, *ptrref);
-        *ptrref = NULL;
-    }
-}
-
-size_t GetMemPoolFreeMemory(const MemPool mempool)
-{
-    size_t total_remaining = mempool.arena.offs - mempool.arena.mem;
-
-    for (MemNode *n = mempool.large.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].head; n != NULL; n = n->next) total_remaining += n->size;
-
-    return total_remaining;
-}
-
-void MemPoolReset(MemPool *const mempool)
-{
-    mempool->large.head = mempool->large.tail = NULL;
-    mempool->large.len = 0;
-
-    for (size_t i = 0; i < MEMPOOL_BUCKET_SIZE; i++)
-    {
-        mempool->buckets[i].head = mempool->buckets[i].tail = NULL;
-        mempool->buckets[i].len = 0;
-    }
-
-    mempool->arena.offs = mempool->arena.mem + mempool->arena.size;
-}
-
-//----------------------------------------------------------------------------------
-// Module Functions Definition - Object Pool
-//----------------------------------------------------------------------------------
-
-ObjPool CreateObjPool(const size_t objsize, const size_t len)
-{
-    ObjPool objpool = { 0 };
-
-    if ((len == 0) || (objsize == 0)) return objpool;
-    else
-    {
-        const size_t aligned_size = __AlignSize(objsize, sizeof(size_t));
-        uint8_t *const restrict buf = calloc(len, aligned_size);
-
-        if (buf == NULL) return objpool;
-        objpool.objSize = aligned_size;
-        objpool.memSize = objpool.freeBlocks = len;
-        objpool.mem = (uintptr_t)buf;
-
-        for (size_t i=0; i<objpool.freeBlocks; i++)
-        {
-            size_t *const restrict index = (size_t *)(objpool.mem + (i*aligned_size));
-            *index = i + 1;
-        }
-
-        objpool.offs = objpool.mem;
-        return objpool;
-    }
-}
-
-ObjPool CreateObjPoolFromBuffer(void *const restrict 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
-    const size_t aligned_size = __AlignSize(objsize, sizeof(size_t));
-
-    if ((buf == NULL) || (len == 0) || (objsize < sizeof(size_t)) || (objsize*len != aligned_size*len)) return objpool;
-    else
-    {
-        objpool.objSize = aligned_size;
-        objpool.memSize = objpool.freeBlocks = len;
-        objpool.mem = (uintptr_t)buf;
-
-        for (size_t i=0; i<objpool.freeBlocks; i++)
-        {
-            size_t *const restrict index = (size_t *)(objpool.mem + (i*aligned_size));
-            *index = i + 1;
-        }
-
-        objpool.offs = objpool.mem;
-        return objpool;
-    }
-}
-
-void DestroyObjPool(ObjPool *const restrict objpool)
-{
-    if (objpool->mem == 0) return;
-    else
-    {
-        void *const restrict ptr = (void *)objpool->mem;
-        free(ptr);
-
-        *objpool = (ObjPool){ 0 };
-    }
-}
-
-void *ObjPoolAlloc(ObjPool *const objpool)
-{
-    if (objpool->freeBlocks > 0)
-    {
-        // For first allocation, head points to the very first index.
-        // Head = &pool[0];
-        // ret = Head == ret = &pool[0];
-        size_t *const restrict block = (size_t *)objpool->offs;
-        objpool->freeBlocks--;
-
-        // After allocating, we set head to the address of the index that *Head holds.
-        // Head = &pool[*Head * pool.objsize];
-        objpool->offs = (objpool->freeBlocks != 0)? objpool->mem + (*block*objpool->objSize) : 0;
-
-        return memset(block, 0, objpool->objSize);
-    }
-    else return NULL;
-}
-
-void ObjPoolFree(ObjPool *const restrict objpool, void *const ptr)
-{
-    uintptr_t block = (uintptr_t)ptr;
-
-    if ((ptr == NULL) || (block < objpool->mem) || (block > objpool->mem + objpool->memSize*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;
-        size_t *const restrict index = (size_t *)block;
-        *index = (objpool->offs != 0)? (objpool->offs - objpool->mem)/objpool->objSize : objpool->memSize;
-        objpool->offs = block;
-        objpool->freeBlocks++;
-    }
-}
-
-void ObjPoolCleanUp(ObjPool *const restrict objpool, void **const restrict ptrref)
-{
-    if (ptrref == NULL) return;
-    else
-    {
-        ObjPoolFree(objpool, *ptrref);
-        *ptrref = NULL;
-    }
-}
-
-
-//----------------------------------------------------------------------------------
-// Module Functions Definition - Double-Ended Stack
-//----------------------------------------------------------------------------------
-
-BiStack CreateBiStack(const size_t len)
-{
-    BiStack destack = { 0 };
-
-    if (len == 0) return destack;
-
-    uint8_t *const buf = malloc(len*sizeof *buf);
-    if (buf == NULL) return destack;
-    destack.size = len;
-    destack.mem = (uintptr_t)buf;
-    destack.front = destack.mem;
-    destack.back = destack.mem + len;
-
-    return destack;
-}
-
-BiStack CreateBiStackFromBuffer(void *const buf, const size_t len)
-{
-    BiStack destack = { 0 };
-
-    if ((len == 0) || (buf == NULL)) return destack;
-    else
-    {
-        destack.size = len;
-        destack.mem = destack.front = (uintptr_t)buf;
-        destack.back = destack.mem + len;
-
-        return destack;
-    }
-}
-
-void DestroyBiStack(BiStack *const restrict destack)
-{
-    if (destack->mem == 0) return;
-    else
-    {
-        uint8_t *const restrict buf = (uint8_t *)destack->mem;
-        free(buf);
-        *destack = (BiStack){ 0 };
-    }
-}
-
-void *BiStackAllocFront(BiStack *const restrict destack, const size_t len)
-{
-    if (destack->mem == 0) return NULL;
-    else
-    {
-        const size_t ALIGNED_LEN = __AlignSize(len, sizeof(uintptr_t));
-        // front end arena is too high!
-        if (destack->front + ALIGNED_LEN >= destack->back) return NULL;
-        else
-        {
-            uint8_t *const restrict ptr = (uint8_t *)destack->front;
-            destack->front += ALIGNED_LEN;
-
-            return ptr;
-        }
-    }
-}
-
-void *BiStackAllocBack(BiStack *const restrict destack, const size_t len)
-{
-    if (destack->mem == 0) return NULL;
-    else
-    {
-        const size_t ALIGNED_LEN = __AlignSize(len, sizeof(uintptr_t));
-        // back end arena is too low
-        if (destack->back - ALIGNED_LEN <= destack->front) return NULL;
-        else
-        {
-            destack->back -= ALIGNED_LEN;
-            uint8_t *const restrict ptr = (uint8_t *)destack->back;
-
-            return ptr;
-        }
-    }
-}
-
-void BiStackResetFront(BiStack *const destack)
-{
-    if (destack->mem == 0) return;
-    else destack->front = destack->mem;
-}
-
-void BiStackResetBack(BiStack *const destack)
-{
-    if (destack->mem == 0) return;
-    else destack->back = destack->mem + destack->size;
-}
-
-void BiStackResetAll(BiStack *const destack)
-{
-    BiStackResetBack(destack);
-    BiStackResetFront(destack);
-}
-
-inline intptr_t BiStackMargins(const BiStack destack)
-{
-    return destack.back - destack.front;
-}
-
-#endif  // RMEM_IMPLEMENTATION