123 lines
3.1 KiB
C
123 lines
3.1 KiB
C
#include "mem_arena.h"
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#include "aliases.h"
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#include "mem_utils.h"
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#include <stdbool.h>
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#include <stdlib.h>
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#include <string.h>
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#ifndef DEFAULT_ALIGNMENT
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// Why 2 * sizeof(void *) instead of sizeof(void *)
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// https://handmade.network/forums/t/6860-alignment_arena_allocator
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#define DEFAULT_ALIGNMENT (2 * sizeof(void *))
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#endif /* ifndef DEFAULT_ALIGNMENT */
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#define ARENA_MINIMUM_CAPACITY 1024
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struct arena {
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u8 *buf;
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u8 *offset;
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u64 capacity;
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bool committed;
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#ifdef WAPP_PLATFORM_WINDOWS
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wapp_misc_utils_padding_size(sizeof(u8 *) * 2 + sizeof(u64) + sizeof(bool));
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#endif // ifdef WAPP_PLATFORM_WINDOWS
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};
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/***************************************************************************/ //
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////////////////////////////////////////////////////////////////////////////////
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////// Arena API definitions
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////////////////////////////////////////////////////////////////////////////////
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/***************************************************************************/ //
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bool wapp_mem_arena_init_custom(Arena **arena, u64 base_capacity,
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MemAllocFlags flags, bool zero_buffer) {
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if (!arena || *arena || base_capacity == 0) {
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return false;
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}
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*arena = (Arena *)calloc(1, sizeof(Arena));
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Arena *arena_ptr = *arena;
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if (!arena_ptr) {
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return false;
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}
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u64 arena_capacity = base_capacity >= ARENA_MINIMUM_CAPACITY
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? base_capacity
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: ARENA_MINIMUM_CAPACITY;
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arena_ptr->buf = (u8 *)wapp_mem_util_alloc(
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NULL, arena_capacity, WAPP_MEM_ACCESS_READ_WRITE, flags,
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zero_buffer ? WAPP_MEM_INIT_INITIALISED : WAPP_MEM_INIT_UNINITIALISED);
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if (!(arena_ptr->buf)) {
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wapp_mem_arena_destroy(arena);
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return false;
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}
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arena_ptr->capacity = arena_capacity;
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arena_ptr->offset = arena_ptr->buf;
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arena_ptr->committed =
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(flags & WAPP_MEM_ALLOC_COMMIT) == WAPP_MEM_ALLOC_COMMIT;
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return true;
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}
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void *wapp_mem_arena_alloc(Arena *arena, u64 size) {
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return wapp_mem_arena_alloc_aligned(arena, size, DEFAULT_ALIGNMENT);
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}
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void *wapp_mem_arena_alloc_aligned(Arena *arena, u64 size, u64 alignment) {
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if (!arena) {
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return NULL;
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}
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u8 *alloc_start = arena->offset;
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u8 *output = wapp_mem_util_align_forward((void *)alloc_start, alignment);
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if (output + size >= arena->buf + arena->capacity) {
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return NULL;
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}
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arena->offset = output + size;
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#ifdef WAPP_PLATFORM_WINDOWS
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if (!(arena->committed)) {
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output = (u8 *)wapp_mem_util_alloc(
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alloc_start, (uptr)(arena->offset) - (uptr)(alloc_start),
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WAPP_MEM_ACCESS_READ_WRITE, WAPP_MEM_ALLOC_COMMIT,
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WAPP_MEM_INIT_INITIALISED);
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}
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#else
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memset(output, 0, size);
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#endif // ifdef WAPP_PLATFORM_WINDOWS
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return (void *)output;
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}
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void wapp_mem_arena_clear(Arena *arena) {
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if (!arena) {
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return;
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}
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memset(arena->buf, 0, arena->offset - arena->buf);
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arena->offset = arena->buf;
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}
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void wapp_mem_arena_destroy(Arena **arena) {
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if (!arena) {
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return;
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}
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Arena *arena_ptr = *arena;
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if (arena_ptr->buf) {
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wapp_mem_util_free(arena_ptr->buf, arena_ptr->capacity);
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}
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arena_ptr->buf = arena_ptr->offset = NULL;
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arena_ptr->capacity = 0;
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free(*arena);
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*arena = NULL;
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}
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