arena -> prick_arena
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@@ -1,30 +1,30 @@
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/* Copyright (C) 2024 Aryadev Chavali
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the Unlicense
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* for details.
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* You may distribute and modify this code under the terms of the
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* Unlicense, which you should have received a copy of along with this
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* program. If not, please go to <https://unlicense.org/>.
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/* prick_arena.h: An arena implementation.
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* Created: 2024-11-01
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* Author: Aryadev Chavali
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* Description: Arena allocator.
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* License: see end of file
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* Commentary:
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To utilise this library, please put:
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#define PRICK_ARENA_IMPL
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#include "prick_arena.h"
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in one of your code units.
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This library defines both:
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- A simple bump allocator for regions, with the ability to attach more regions
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via a linked list in case the current region when the current region is full.
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- A simple arena memory allocator, using the bump allocator for its regions.
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The regions of the arena are arranged in a linked list for simplicity. As
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regions aren't reallocated (instead, a new region is generated), they are
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stable pointers, and may be used throughout a program as long as the underlying
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arena isn't deleted.
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*/
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#ifndef ARENA_H
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#define ARENA_H
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#ifndef PRICK_ARENA_H
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#define PRICK_ARENA_H
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#include <stdint.h>
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/**
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@brief A single block of memory to be used by an arena.
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@details Blocks of memory arranged in a singly linked list.
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Each individual node is a bump allocator.
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*/
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typedef struct Region
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{
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struct Region *next;
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@@ -32,38 +32,9 @@ typedef struct Region
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uint8_t bytes[];
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} region_t;
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/**
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@brief Allocate a new region on the heap with requested size and a pointer to
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the next region.
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@details If capacity is less than REGION_DEFAULT_SIZE, capacity is set to
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REGION_DEFAULT_SIZE.
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*/
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region_t *region_make(uint32_t capacity, region_t *next);
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/**
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@brief Allocate memory of requested size on the region.
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@details If the region cannot fit the requested size, then return NULL.
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Otherwise return a pointer to the start of the allocated memory, incrementing
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the region size appropriately.
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*/
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uint8_t *region_alloc_flat(region_t *region, uint32_t size);
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/**
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@brief Allocate memory of requested size on the region.
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@details Iterates through the linked list of regions to find an appropriately
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sized region for the requested size, allocating a new region if one cannot be
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found. This new region will have capacity at least size *
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REGION_CAPACITY_MULT.
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Returns a pointer to the start of the allocated memory, incrementing the
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appropriate region's size.
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*/
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uint8_t *region_alloc_rec(region_t *region, uint32_t size);
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/**
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@brief Delete a region, freeing its memory.
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@details Will free all regions following it in the linked list.
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*/
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void region_delete_rec(region_t *region);
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typedef struct
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@@ -71,46 +42,13 @@ typedef struct
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region_t *beg, *end;
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} arena_t;
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/**
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@brief Allocate memory of requested size in the arena, returning a pointer to
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the start of it.
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@details Uses region_alloc_rec internally to allocate the memory required.
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arena->beg and arena->end are set appropriately for this task.
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*/
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uint8_t *arena_alloc(arena_t *arena, uint32_t size);
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/**
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@brief Reallocate buffer of old_size to a buffer of new_size in the
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arena, returning a pointer to the start of the new buffer.
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@details If the pointer is not allocated in the arena, return NULL. If the
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pointer and old_size cover a complete region reallocate the region itself to
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fit the newly requested size, relinking it in the linked list. Otherwise,
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allocate as per usual.
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The contents of the old memory are copied into the new buffer. If old_size >
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new_size, only new_size bytes will be copied from the old buffer into the new
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one.
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*/
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uint8_t *arena_realloc(arena_t *arena, uint8_t *pointer, uint32_t old_size,
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uint32_t new_size);
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/**
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@brief Reset the arena for reuse.
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@details Sets all regions to default values, setting size to 0. No memory is
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deleted in this operation.
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*/
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void arena_reset(arena_t *arena);
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/**
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@brief Free the memory associated with the arena.
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@details Deletes all regions of memory associated in the arena.
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*/
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void arena_free(arena_t *arena);
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#ifdef ARENA_IMPL
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#ifdef PRICK_ARENA_IMPL
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#include <malloc.h>
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#include <string.h>
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@@ -239,3 +177,15 @@ void arena_free(arena_t *arena)
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#endif
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#endif
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/* Copyright (C) 2024 Aryadev Chavali
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the Unlicense
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* for details.
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* You may distribute and modify this code under the terms of the
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* Unlicense, which you should have received a copy of along with this
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* program. If not, please go to <https://unlicense.org/>.
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*/
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