feat(arena.c): Added arena init and added ArenaResult

Want to handle errors with results, even if it meas boilerplate

include/arena.h

@@ -17,6 +17,7 @@ typedef enum {
     ARENA_BAD_ALLOC,
     ARENA_OUT_OF_SPACE,
     ARENA_NULL_ARG,
+    ARENA_INVALID_SIZE,
 } ArenaErr;
 
 typedef struct {
@@ -27,11 +28,19 @@ typedef struct {
     };
 } ArenaPointer;
 
-Arena arena_init(void *buffer, size_t size);
+typedef struct {
+    bool is_valid;
+    union {
+        ArenaErr err;
+        Arena arena;
+    };
+} ArenaResult;
+
+ArenaResult arena_init(void *buffer, size_t size);
 void arena_destroy(Arena *arena);
 
 ArenaPointer arena_alloc(Arena *arena, size_t size, size_t alignment);
-ArenaPointer arena_push(Arena *arena, void *data);
+ArenaErr arena_push(Arena *arena, void *data, size_t size);
 ArenaErr arena_realloc(Arena *arena, size_t new_size);
 
 size_t align_arena_offset(Arena *arena, size_t alignment);

src/arena.c

@@ -1 +1,34 @@
 #include "arena.h"
+#include <stdbool.h>
+#include <stdlib.h>
+
+ArenaResult arena_init(void *buffer, size_t size) {
+    if (buffer == NULL) {
+        ArenaResult err = {
+            .is_valid = false,
+            .err = ARENA_NULL_ARG,
+        };
+        return err;
+    }
+
+    if (size < 1) {
+        ArenaResult err = {
+            .is_valid = false,
+            .err = ARENA_INVALID_SIZE,
+        };
+        return err;
+    }
+
+    Arena new_arena = {
+        .data = buffer,
+        .size = size,
+        .offset = 0,
+    };
+
+    ArenaResult val = {
+        .is_valid = true,
+        .arena = new_arena,
+    };
+
+    return val;
+}