#include "arena.h"

#include <stdlib.h>
#include <string.h>

// arena_new creates a new arena with the specified size.
arena_t* arena_new(size_t size) {
	arena_t *a = malloc(sizeof(arena_t));
	if (!a) return NULL;

	a->buf = malloc(size);
	if (!a->buf) {
		free(a);
		return NULL;
	}

	a->size = size;
	a->used = 0;
	a->next = NULL;
	return a;
}

// arena_free destroys the arena and its buffer.
void arena_free(arena_t *a) {
	if (!a) return;

	// Free chained arenas if any
	arena_t *next;
	while (a) {
		next = a->next;
		free(a->buf);
		free(a);
		a = next;
	}
}

// arena_alloc allocates memory from the arena.
void* arena_alloc(arena_t *a, size_t size) {
	// Align to 8 bytes for proper alignment
	size = (size + 7) & ~7;

	if (a->used + size > a->size) {
		// Could implement arena chaining here
		// For now, just fail
		return NULL;
	}

	void *ptr = a->buf + a->used;
	a->used += size;
	return ptr;
}

// arena_strdup duplicates a string into the arena.
char* arena_strdup(arena_t *a, const char *s, size_t len) {
	char *copy = arena_alloc(a, len + 1);
	if (!copy) return NULL;
	memcpy(copy, s, len);
	copy[len] = '\0';
	return copy;
}

// arena_reset resets the arena for reuse.
void arena_reset(arena_t *a) {
	a->used = 0;
	// Could reset chained arenas here if implemented
}