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/* Copyright (C) 2022 Wildfire Games.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#ifndef INCLUDED_ALLOCATORS_PAGE_ALIGNED
#define INCLUDED_ALLOCATORS_PAGE_ALIGNED
#include "lib/posix/posix_mman.h" // PROT_*
// very thin wrapper on top of sys/mman.h that makes the intent more obvious
// (its commit/decommit semantics are difficult to tell apart)
Status mem_Reserve(size_t size, u8** pp);
Status mem_Release(u8* p, size_t size);
Status mem_Commit(u8* p, size_t size, int prot);
Status mem_Decommit(u8* p, size_t size);
Status mem_Protect(u8* p, size_t size, int prot);
/**
* allocate memory aligned to the system page size.
*
* this is useful for file_cache_alloc, which uses this allocator to
* get sector-aligned (hopefully; see sys_max_sector_size) IO buffers.
*
* note that this allocator is stateless and very little error checking
* can be performed.
*
* the memory is initially writable and you can use mprotect to set other
* access permissions if desired.
*
* @param unaligned_size minimum size [bytes] to allocate.
* @return page-aligned and -padded memory or 0 on error / out of memory.
**/
void* page_aligned_alloc(size_t unaligned_size);
/**
* free a previously allocated page-aligned region.
*
* @param p Exact value returned from page_aligned_alloc
* @param unaligned_size Exact value passed to page_aligned_alloc
**/
void page_aligned_free(void* p, size_t unaligned_size);
#endif // #ifndef INCLUDED_ALLOCATORS_PAGE_ALIGNED
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