forked from 0ad/0ad
108 lines
3.1 KiB
C
108 lines
3.1 KiB
C
/* Copyright (c) 2010 Wildfire Games
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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/*
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* dynamic (expandable) array
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*/
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#ifndef INCLUDED_ALLOCATORS_DYNARRAY
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#define INCLUDED_ALLOCATORS_DYNARRAY
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#include "lib/posix/posix_mman.h" // PROT_*
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/**
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* provides a memory range that can be expanded but doesn't waste
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* physical memory or relocate itself.
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*
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* works by preallocating address space and committing as needed.
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* used as a building block for other allocators.
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**/
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struct DynArray
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{
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u8* base;
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size_t max_size_pa; /// reserved
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size_t cur_size; /// committed
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size_t cur_size_pa;
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size_t pos;
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};
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/**
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* ready the DynArray object for use.
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*
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* no virtual memory is actually committed until calls to da_set_size.
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*
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* @param da DynArray.
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* @param max_size size [bytes] of address space to reserve (*);
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* the DynArray can never expand beyond this.
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* (* rounded up to next page size multiple)
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* @return Status.
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**/
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LIB_API Status da_alloc(DynArray* da, size_t max_size);
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/**
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* free all memory (address space + physical) that constitutes the
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* given array.
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*
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* use-after-free is impossible because the memory is unmapped.
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*
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* @param da DynArray* zeroed afterwards.
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* @return Status
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**/
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LIB_API Status da_free(DynArray* da);
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/**
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* expand or shrink the array: changes the amount of currently committed
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* (i.e. usable) memory pages.
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*
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* @param da DynArray.
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* @param new_size target size (rounded up to next page multiple).
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* pages are added/removed until this is met.
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* @return Status.
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**/
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LIB_API Status da_set_size(DynArray* da, size_t new_size);
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/**
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* Make sure at least \<size\> bytes starting at da->pos are committed and
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* ready for use.
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*
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* @param da DynArray*
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* @param size Minimum amount to guarantee [bytes]
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* @return Status
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**/
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LIB_API Status da_reserve(DynArray* da, size_t size);
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/**
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* "write" to array, i.e. copy from the given buffer.
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*
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* starts at offset DynArray.pos and advances this.
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*
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* @param da DynArray.
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* @param data_src source memory
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* @param size [bytes] to copy
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* @return Status.
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**/
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LIB_API Status da_append(DynArray* da, const void* data_src, size_t size);
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#endif // #ifndef INCLUDED_ALLOCATORS_DYNARRAY
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