include/arena.h

@@ -6,11 +6,7 @@
 #include <inttypes.h>
 #include <stdbool.h>
 
-typedef struct {
-    uint8_t *buffer;
-    size_t capacity;
-    size_t offset;
-} Arena;
+typedef struct Arena Arena;
 
 typedef enum {
     ARENA_OK = 0,
@@ -37,7 +33,7 @@ typedef struct {
     bool is_valid;
     union {
         ArenaErr err;
-        Arena arena;
+        Arena *arena;
     };
 } ArenaResult;
 
@@ -49,8 +45,8 @@ typedef struct {
     };
 } ArenaSizeResult;
 
-ArenaResult arena_init(size_t capacity);
-void arena_destroy(Arena *arena);
+ArenaErr arena_init(Arena **arena, size_t capacity);
+ArenaErr arena_destroy(Arena **arena);
 
 ArenaPointer arena_alloc(Arena *arena, size_t size, size_t alignment);
 ArenaPointer arena_push(Arena *arena, void *data, size_t size, size_t alignment);

src/arena.c

@@ -5,32 +5,56 @@
 #include <stdlib.h>
 #include <string.h>
 
+struct Arena {
+    uint8_t *buffer;
+    size_t capacity;
+    size_t offset;
+};
 
 
-ArenaResult arena_init(size_t capacity) {
+ArenaErr arena_init(Arena **arena, size_t capacity) {
+    if (arena == NULL) {
+        return ARENA_NULL_ARG;
+    }
+
     if (capacity < 1) {
-        return (ArenaResult) {.is_valid = false, .err = ARENA_INVALID_SIZE};
+        return ARENA_INVALID_SIZE;
+    }
+
+    Arena *new_arena = malloc(sizeof(Arena));
+    if (new_arena == NULL) {
+        return ARENA_BAD_ALLOC;
     }
 
     void *buffer = malloc(capacity);
     if (buffer == NULL) {
-        return (ArenaResult) {.is_valid = false, .err = ARENA_BAD_ALLOC};
+        return ARENA_BAD_ALLOC;
     }
 
-    Arena new_arena = {
+    *new_arena = (Arena) {
         .buffer = buffer,
         .capacity = capacity,
         .offset = 0,
     };
 
-    return (ArenaResult) {.is_valid = true, .arena = new_arena};
+    *arena = new_arena;
+
+    return ARENA_OK;
 }
 
-void arena_destroy(Arena *arena) {
-    free(arena->buffer);
-    arena->buffer = NULL;
-    arena->offset = 0;
-    arena->capacity = 0;
+ArenaErr arena_destroy(Arena **arena) {
+    if (arena == NULL || *arena == NULL) {
+        return ARENA_NULL_ARG;
+    }
+
+    free((*arena)->buffer);
+    (*arena)->buffer = NULL;
+    (*arena)->offset = 0;
+    (*arena)->capacity = 0;
+    free(*arena);
+    *arena = NULL;
+
+    return ARENA_OK;
 }
 
 ArenaPointer arena_alloc(Arena *arena, size_t size, size_t alignment) {
@@ -51,6 +75,11 @@ ArenaPointer arena_alloc(Arena *arena, size_t size, size_t alignment) {
         return (ArenaPointer) {.is_valid = false, .err = padding.err};
     }
 
+    ArenaErr cap_err = arena_ensure_capacity(arena, size, alignment);
+    if(cap_err != ARENA_OK) {
+        return (ArenaPointer) {.is_valid = false, .err = ARENA_OUT_OF_SPACE};
+    }
+
     if (arena->offset + padding.val + size > arena->capacity) {
         return (ArenaPointer) {.is_valid = false, .err = ARENA_OUT_OF_SPACE};
     }

test/test_arena.c

@@ -14,23 +14,22 @@
 static void test_push_3_ints(void **state) {
     (void) state;
 
-    ArenaResult value = arena_init(sizeof(int) * 3);
-    assert_true(value.is_valid);
-    Arena arena = value.arena;
+    Arena *arena;
+    assert_uint_equal(arena_init(&arena, sizeof(int) * 3), ARENA_OK);
 
     int int_to_push = 20;
-    ArenaPointer result = arena_push(&arena, &int_to_push, sizeof(int), alignof(int));
+    ArenaPointer result = arena_push(arena, &int_to_push, sizeof(int), alignof(int));
     assert_true(result.is_valid);
     assert_int_equal(20, *(int*)arena_unwrap_pointer(result));
     assert_int_equal(20, *(int*)arena_unwrap_pointer(result));
 
     int_to_push = 30;
-    result = arena_push(&arena, &int_to_push, sizeof(int), alignof(int));
+    result = arena_push(arena, &int_to_push, sizeof(int), alignof(int));
     assert_true(result.is_valid);
     assert_int_equal(30, *(int*)arena_unwrap_pointer(result));
 
     int_to_push = 40;
-    result = arena_push(&arena, &int_to_push, sizeof(int), alignof(int));
+    result = arena_push(arena, &int_to_push, sizeof(int), alignof(int));
     assert_true(result.is_valid);
     assert_int_equal(40, *(int*)arena_unwrap_pointer(result));
 
@@ -40,32 +39,34 @@ static void test_push_3_ints(void **state) {
 static void test_push_3_ints_2_doubles(void **state) {
     (void) state;
 
-    ArenaResult value = arena_init((sizeof(int) * 3) + (sizeof(double) * 2));
-    assert_true(value.is_valid);
-    Arena arena = value.arena;
+    Arena *arena;
+    assert_uint_equal(
+        arena_init(&arena, (sizeof(int) * 3) + (sizeof(double) * 2)),
+        ARENA_OK
+    );
 
     int int_to_push = 20;
-    ArenaPointer result = arena_push(&arena, &int_to_push, sizeof(int), alignof(int));
+    ArenaPointer result = arena_push(arena, &int_to_push, sizeof(int), alignof(int));
     assert_true(result.is_valid);
     assert_int_equal(20, *(int*)arena_unwrap_pointer(result));
 
     double double_to_push = 4.57;
-    result = arena_push(&arena, &double_to_push, sizeof(double), alignof(double));
+    result = arena_push(arena, &double_to_push, sizeof(double), alignof(double));
     assert_true(result.is_valid);
     assert_double_equal(4.57, *(double*)arena_unwrap_pointer(result), 1e-6);
 
     int_to_push = 30;
-    result = arena_push(&arena, &int_to_push, sizeof(int), alignof(int));
+    result = arena_push(arena, &int_to_push, sizeof(int), alignof(int));
     assert_true(result.is_valid);
     assert_int_equal(30, *(int*)arena_unwrap_pointer(result));
 
     int_to_push = 40;
-    result = arena_push(&arena, &int_to_push, sizeof(int), alignof(int));
+    result = arena_push(arena, &int_to_push, sizeof(int), alignof(int));
     assert_true(result.is_valid);
     assert_int_equal(40, *(int*)arena_unwrap_pointer(result));
 
     double_to_push = 267.33;
-    result = arena_push(&arena, &double_to_push, sizeof(double), alignof(double));
+    result = arena_push(arena, &double_to_push, sizeof(double), alignof(double));
     assert_true(result.is_valid);
     assert_double_equal(267.33, *(double*)arena_unwrap_pointer(result), 1e-6);
 
@@ -75,19 +76,17 @@ static void test_push_3_ints_2_doubles(void **state) {
 static void test_init_arena_0_cap(void **state) {
     (void) state;
 
-    ArenaResult arena = arena_init(0);
-    assert_false(arena.is_valid);
-    assert_int_equal(arena.err, ARENA_INVALID_SIZE);
+    Arena *arena;
+    assert_int_equal(arena_init(&arena, 0), ARENA_INVALID_SIZE);
 }
 
 static void test_arena_alloc_size_0(void **state) {
     (void) state;
 
-    ArenaResult value = arena_init(64);
-    assert_true(value.is_valid);
-    Arena arena = value.arena;
+    Arena *arena;
+    assert_uint_equal(arena_init(&arena, 64), ARENA_OK);
 
-    ArenaPointer pointer = arena_alloc(&arena, 0, alignof(int));
+    ArenaPointer pointer = arena_alloc(arena, 0, alignof(int));
     assert_false(pointer.is_valid);
     assert_int_equal(pointer.err, ARENA_INVALID_SIZE);
 
@@ -97,11 +96,10 @@ static void test_arena_alloc_size_0(void **state) {
 static void test_arena_alloc_size_max(void **state) {
     (void) state;
 
-    ArenaResult value = arena_init(64);
-    assert_true(value.is_valid);
-    Arena arena = value.arena;
+    Arena *arena;
+    assert_uint_equal(arena_init(&arena, 64), ARENA_OK);
 
-    ArenaPointer pointer = arena_alloc(&arena, SIZE_MAX, alignof(int));
+    ArenaPointer pointer = arena_alloc(arena, SIZE_MAX, alignof(int));
     assert_false(pointer.is_valid);
     assert_int_equal(pointer.err, ARENA_OUT_OF_SPACE);
 
@@ -111,11 +109,10 @@ static void test_arena_alloc_size_max(void **state) {
 static void test_arena_alloc_align_0(void **state) {
     (void) state;
 
-    ArenaResult value = arena_init(64);
-    assert_true(value.is_valid);
-    Arena arena = value.arena;
+    Arena *arena;
+    assert_uint_equal(arena_init(&arena, 64), ARENA_OK);
 
-    ArenaPointer pointer = arena_alloc(&arena, sizeof(int), 0);
+    ArenaPointer pointer = arena_alloc(arena, sizeof(int), 0);
     assert_false(pointer.is_valid);
     assert_int_equal(pointer.err, ARENA_INVALID_ALIGN);
 
@@ -125,11 +122,10 @@ static void test_arena_alloc_align_0(void **state) {
 static void test_arena_alloc_align_max(void **state) {
     (void) state;
 
-    ArenaResult value = arena_init(64);
-    assert_true(value.is_valid);
-    Arena arena = value.arena;
+    Arena *arena;
+    assert_uint_equal(arena_init(&arena, 64), ARENA_OK);
 
-    ArenaPointer pointer = arena_alloc(&arena, sizeof(int), SIZE_MAX);
+    ArenaPointer pointer = arena_alloc(arena, sizeof(int), SIZE_MAX);
     assert_false(pointer.is_valid);
     assert_int_equal(pointer.err, ARENA_INVALID_ALIGN);
 
@@ -139,11 +135,10 @@ static void test_arena_alloc_align_max(void **state) {
 static void test_arena_align_size_0(void **state) {
     (void) state;
 
-    ArenaResult value = arena_init(64);
-    assert_true(value.is_valid);
-    Arena arena = value.arena;
+    Arena *arena;
+    assert_uint_equal(arena_init(&arena, 64), ARENA_OK);
 
-    ArenaPointer pointer = arena_alloc(&arena, sizeof(int), 0);
+    ArenaPointer pointer = arena_alloc(arena, sizeof(int), 0);
     assert_false(pointer.is_valid);
     assert_int_equal(pointer.err, ARENA_INVALID_ALIGN);
 
@@ -153,11 +148,10 @@ static void test_arena_align_size_0(void **state) {
 static void test_arena_ensure_capacity_size_0(void **state) {
     (void) state;
 
-    ArenaResult value = arena_init(64);
-    assert_true(value.is_valid);
-    Arena arena = value.arena;
+    Arena *arena;
+    assert_uint_equal(arena_init(&arena, 64), ARENA_OK);
 
-    ArenaErr err = arena_ensure_capacity(&arena, 0, alignof(int));
+    ArenaErr err = arena_ensure_capacity(arena, 0, alignof(int));
     assert_int_equal(err, ARENA_INVALID_SIZE);
 
     arena_destroy(&arena);
@@ -166,11 +160,10 @@ static void test_arena_ensure_capacity_size_0(void **state) {
 static void test_arena_ensure_capacity_size_max(void **state) {
     (void) state;
 
-    ArenaResult value = arena_init(64);
-    assert_true(value.is_valid);
-    Arena arena = value.arena;
+    Arena *arena;
+    assert_uint_equal(arena_init(&arena, 64), ARENA_OK);
 
-    ArenaErr err = arena_ensure_capacity(&arena, SIZE_MAX, alignof(int));
+    ArenaErr err = arena_ensure_capacity(arena, SIZE_MAX, alignof(int));
     assert_int_equal(err, ARENA_INVALID_SIZE);
 
     arena_destroy(&arena);
@@ -179,11 +172,10 @@ static void test_arena_ensure_capacity_size_max(void **state) {
 static void test_arena_ensure_capacity_align_0(void **state) {
     (void) state;
 
-    ArenaResult value = arena_init(64);
-    assert_true(value.is_valid);
-    Arena arena = value.arena;
+    Arena *arena;
+    assert_uint_equal(arena_init(&arena, 64), ARENA_OK);
 
-    ArenaErr err = arena_ensure_capacity(&arena, sizeof(int), 0);
+    ArenaErr err = arena_ensure_capacity(arena, sizeof(int), 0);
     assert_int_equal(err, ARENA_INVALID_ALIGN);
 
     arena_destroy(&arena);
@@ -192,11 +184,10 @@ static void test_arena_ensure_capacity_align_0(void **state) {
 static void test_arena_ensure_capacity_align_max(void **state) {
     (void) state;
 
-    ArenaResult value = arena_init(64);
-    assert_true(value.is_valid);
-    Arena arena = value.arena;
+    Arena *arena;
+    assert_uint_equal(arena_init(&arena, 64), ARENA_OK);
 
-    ArenaErr err = arena_ensure_capacity(&arena, sizeof(int), SIZE_MAX);
+    ArenaErr err = arena_ensure_capacity(arena, sizeof(int), SIZE_MAX);
     assert_int_equal(err, ARENA_INVALID_ALIGN);
 
     arena_destroy(&arena);