Reorganise the code

src/mem/arena/mem_arena.c

@@ -0,0 +1,233 @@
+#include "mem_arena.h"
+#include "aliases.h"
+#include "mem_utils.h"
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifndef DEFAULT_ALIGNMENT
+// Why 2 * sizeof(void *) instead of sizeof(void *)
+// https://handmade.network/forums/t/6860-alignment_arena_allocator
+#define DEFAULT_ALIGNMENT (2 * sizeof(void *))
+#endif /* ifndef DEFAULT_ALIGNMENT */
+
+#define ARENA_MINIMUM_CAPACITY 1024
+
+typedef struct base_arena BaseArena;
+struct base_arena {
+  u8 *buf;
+  u8 *offset;
+  u64 capacity;
+  BaseArena *prev;
+  BaseArena *next;
+};
+
+struct growing_arena {
+  BaseArena *active_arena;
+  u64 count;
+  u64 initial_capacity;
+};
+
+internal bool base_arena_init(BaseArena *arena, u64 capacity);
+internal void *base_arena_alloc_aligned(BaseArena *arena, u64 size,
+                                        u64 alignment);
+internal void base_arena_clear(BaseArena *arena);
+internal void base_arena_destroy(BaseArena *arena);
+
+// PUBLIC API
+
+bool wapp_mem_arena_init(Arena **arena, u64 base_capacity) {
+  if (!arena || *arena || base_capacity == 0) {
+    return false;
+  }
+
+  *arena = (Arena *)calloc(1, sizeof(Arena));
+  Arena *arena_ptr = *arena;
+  if (!arena_ptr) {
+    return false;
+  }
+
+  arena_ptr->active_arena = (BaseArena *)calloc(1, sizeof(BaseArena));
+  if (!(arena_ptr->active_arena)) {
+    wapp_mem_arena_destroy(arena);
+    return false;
+  }
+
+  if (!base_arena_init(arena_ptr->active_arena, base_capacity)) {
+    wapp_mem_arena_destroy(arena);
+    return false;
+  }
+
+  arena_ptr->count = 1;
+  arena_ptr->initial_capacity = base_capacity;
+
+  return true;
+}
+
+void *wapp_mem_arena_alloc(Arena *arena, u64 size) {
+  return wapp_mem_arena_alloc_aligned(arena, size, DEFAULT_ALIGNMENT);
+}
+
+void *wapp_mem_arena_alloc_aligned(Arena *arena, u64 size, u64 alignment) {
+  if (!arena || !(arena->active_arena)) {
+    return NULL;
+  }
+
+  void *output = base_arena_alloc_aligned(arena->active_arena, size, alignment);
+  if (!output) {
+    if (arena->active_arena->next) {
+      arena->active_arena = arena->active_arena->next;
+    } else {
+      arena->active_arena->next = (BaseArena *)calloc(1, sizeof(BaseArena));
+      if (!(arena->active_arena->next)) {
+        return NULL;
+      }
+
+      if (!base_arena_init(arena->active_arena->next,
+                           arena->initial_capacity)) {
+        free(arena->active_arena->next);
+        return NULL;
+      }
+
+      arena->active_arena->next->prev = arena->active_arena;
+      arena->active_arena = arena->active_arena->next;
+
+      ++(arena->count);
+    }
+
+    output = base_arena_alloc_aligned(arena->active_arena, size, alignment);
+    if (!output) {
+      return NULL;
+    }
+  }
+
+  memset(output, 0, size);
+
+  return output;
+}
+
+void wapp_mem_arena_clear(Arena *arena) {
+  if (!arena) {
+    return;
+  }
+
+  BaseArena *last_active = NULL;
+  while (arena->active_arena) {
+    base_arena_clear(arena->active_arena);
+
+    last_active = arena->active_arena;
+
+    arena->active_arena = arena->active_arena->prev;
+  }
+
+  arena->active_arena = last_active;
+}
+
+void wapp_mem_arena_destroy(Arena **arena) {
+  if (!arena) {
+    return;
+  }
+
+  Arena *arena_ptr = *arena;
+  if (!arena_ptr) {
+    return;
+  }
+
+  BaseArena *current;
+  BaseArena *next;
+  BaseArena *prev;
+
+  current = arena_ptr->active_arena->next;
+  while (current) {
+    next = current->next;
+
+    base_arena_destroy(current);
+    free(current);
+
+    current = next;
+  }
+
+  current = arena_ptr->active_arena->prev;
+  while (current) {
+    prev = current->prev;
+
+    base_arena_destroy(current);
+    free(current);
+
+    current = prev;
+  }
+
+  base_arena_destroy(arena_ptr->active_arena);
+
+  free(arena_ptr->active_arena);
+  arena_ptr->active_arena = NULL;
+
+  arena_ptr->count = 0;
+  arena_ptr->initial_capacity = 0;
+
+  free(*arena);
+  *arena = NULL;
+}
+
+// INTERNAL FUNCTIONS
+
+internal bool base_arena_init(BaseArena *arena, u64 capacity) {
+  if (!arena || arena->buf || capacity == 0) {
+    return false;
+  }
+
+  u64 arena_capacity =
+      capacity >= ARENA_MINIMUM_CAPACITY ? capacity : ARENA_MINIMUM_CAPACITY;
+
+  arena->buf = (u8 *)calloc(arena_capacity, sizeof(u8));
+  if (!(arena->buf)) {
+    return false;
+  }
+
+  arena->capacity = arena_capacity;
+  arena->offset = arena->buf;
+  arena->prev = arena->next = NULL;
+
+  return true;
+}
+
+internal void *base_arena_alloc_aligned(BaseArena *arena, u64 size,
+                                        u64 alignment) {
+  if (!arena) {
+    return NULL;
+  }
+
+  u8 *alloc_start = arena->offset;
+
+  u8 *output = wapp_mem_util_align_forward((void *)alloc_start, alignment);
+  if (output + size >= arena->buf + arena->capacity) {
+    return NULL;
+  }
+
+  arena->offset = output + size;
+
+  return (void *)output;
+}
+
+internal void base_arena_clear(BaseArena *arena) {
+  if (!arena) {
+    return;
+  }
+
+  memset(arena->buf, 0, arena->offset - arena->buf);
+  arena->offset = arena->buf;
+}
+
+internal void base_arena_destroy(BaseArena *arena) {
+  if (!arena) {
+    return;
+  }
+
+  if (arena->buf) {
+    free(arena->buf);
+  }
+
+  arena->buf = arena->offset = NULL;
+  arena->capacity = 0;
+  arena->prev = arena->next = NULL;
+}