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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.
*/
/*
* dynamic (expandable) array
*/
#ifndef INCLUDED_ALLOCATORS_DYNARRAY
#define INCLUDED_ALLOCATORS_DYNARRAY
#include "lib/posix/posix_mman.h" // PROT_*
/**
* provides a memory range that can be expanded but doesn't waste
* physical memory or relocate itself.
*
* works by preallocating address space and committing as needed.
* used as a building block for other allocators.
**/
struct DynArray
{
u8* base;
size_t max_size_pa; /// reserved
size_t cur_size; /// committed
size_t cur_size_pa;
size_t pos;
};
/**
* ready the DynArray object for use.
*
* no virtual memory is actually committed until calls to da_set_size.
*
* @param da DynArray.
* @param max_size size [bytes] of address space to reserve (*);
* the DynArray can never expand beyond this.
* (* rounded up to next page size multiple)
* @return Status.
**/
Status da_alloc(DynArray* da, size_t max_size);
/**
* free all memory (address space + physical) that constitutes the
* given array.
*
* use-after-free is impossible because the memory is unmapped.
*
* @param da DynArray* zeroed afterwards.
* @return Status
**/
Status da_free(DynArray* da);
/**
* expand or shrink the array: changes the amount of currently committed
* (i.e. usable) memory pages.
*
* @param da DynArray.
* @param new_size target size (rounded up to next page multiple).
* pages are added/removed until this is met.
* @return Status.
**/
Status da_set_size(DynArray* da, size_t new_size);
/**
* Make sure at least \<size\> bytes starting at da->pos are committed and
* ready for use.
*
* @param da DynArray*
* @param size Minimum amount to guarantee [bytes]
* @return Status
**/
Status da_reserve(DynArray* da, size_t size);
/**
* "write" to array, i.e. copy from the given buffer.
*
* starts at offset DynArray.pos and advances this.
*
* @param da DynArray.
* @param data_src source memory
* @param size [bytes] to copy
* @return Status.
**/
Status da_append(DynArray* da, const void* data_src, size_t size);
#endif // #ifndef INCLUDED_ALLOCATORS_DYNARRAY
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