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#include <stdlib.h>
/// -------- Basic functions
void *un_memory_alloc(u64 size, Allocator alloc) {
assert(alloc.proc != NULL);
return alloc.proc(NULL, size, UN_DEFAULT_ALIGN, UN_ALLOC_MSG_ALLOCATE, alloc.data);
}
void *un_memory_alloc_align(u64 size, u32 align, Allocator alloc) {
assert(alloc.proc != NULL);
return alloc.proc(NULL, size, align, UN_ALLOC_MSG_ALLOCATE, alloc.data);
}
void un_memory_free(void *ptr, Allocator alloc) {
assert(alloc.proc != NULL);
alloc.proc(ptr, 0, 0, UN_ALLOC_MSG_FREE, alloc.data);
}
/// -------- Std allocator
#if defined(OS_WINDOWS)
# include "un_mem_win_x64.c"
#elif defined(OS_LINUX)
# include "un_mem_linux_x64.c"
#else
# include "un_mem_std.c"
#endif
Allocator un_alloc_std_get(void) {
return CLITERAL(Allocator) { .proc = un_std_alloc_proc };
}
/// Arena allocator
typedef struct Arena {
u8 *buffer;
u64 size, curr_offset, prev_offset;
} Arena;
static Arena __temp_arena;
static Arena arena_create(u64 size) {
Allocator alloc;
Arena arena;
UN_CLEAR(arena);
alloc = un_alloc_std_get();
arena.buffer = un_memory_alloc(size, alloc);
if (arena.buffer == NULL) {
return arena;
}
arena.size = size;
return arena;
}
// special thanks to ginger bill: https://www.gingerbill.org/article/2019/02/08/memory-allocation-strategies-002/
static uintptr_t align_forward(uintptr_t ptr, u32 align) {
uintptr_t p, a, modulo;
assert(UN_POW_OF2(align));
p = ptr;
a = (uintptr_t)align;
modulo = p & (a-1);
if (modulo != 0) {
p += a - modulo;
}
return p;
}
static void* arena_allocate_align(Arena *arena, u32 align, u64 size) {
uintptr_t curr_ptr, offset;
u8 *ptr;
assert(arena != NULL);
curr_ptr = (uintptr_t)arena->buffer + arena->curr_offset;
offset = align_forward(curr_ptr, align);
offset -= (uintptr_t)arena->buffer;
if ((offset + size) <= arena->size) {
ptr = (u8*)(arena->buffer + offset);
arena->prev_offset = offset;
arena->curr_offset = offset + size;
memset(ptr, 0, size);
} else {
ptr = NULL;
}
return ptr;
}
static void arena_free_memory(Arena *arena) {
if (arena == &__temp_arena) return;
assert(arena != NULL);
if (arena->buffer != NULL) {
un_memory_free(arena->buffer, un_alloc_std_get());
}
}
static ALLOCATOR_PROC_SIGNATURE(un_arena_alloc_proc) {
UNUSED(p);
switch (message) {
case UN_ALLOC_MSG_ALLOCATE:
return arena_allocate_align((Arena*)data, align, size);
case UN_ALLOC_MSG_FREE:
break;
case UN_ALLOC_MSG_SELF_DELETE:
arena_free_memory((Arena*)data);
break;
}
return NULL;
}
Allocator un_alloc_arena_create(u64 byte_size) {
Allocator alloc, std;
Arena arena;
UN_CLEAR(alloc);
std = un_alloc_std_get();
alloc.proc = un_arena_alloc_proc;
arena = arena_create(byte_size);
if(arena.buffer == NULL) {
UN_CLEAR(alloc);
}
alloc.data = un_memory_alloc(sizeof(arena), std); // yeah, it allocs 4kb for 32 bytes...
if(alloc.data == NULL) {
arena_free_memory(&arena);
UN_CLEAR(alloc);
return alloc;
}
*((Arena *)alloc.data) = arena;
return alloc;
}
void un_alloc_arena_destroy(Allocator *alloc) {
arena_free_memory((Arena*)alloc->data);
un_memory_free(alloc->data, un_alloc_std_get());
UN_CLEAR(*alloc);
}
void un_alloc_temp_init(u64 byte_size) {
__temp_arena = arena_create(byte_size);
}
void un_alloc_temp_reset(void) {
__temp_arena.curr_offset = 0;
__temp_arena.prev_offset = 0;
}
Allocator un_alloc_temp_get(void) {
assert(__temp_arena.buffer != NULL);
return CLITERAL(Allocator) { un_arena_alloc_proc, &__temp_arena };
}
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