Include super basic memory arena

arena.h

@@ -0,0 +1,47 @@
+#ifndef ARENA_H
+#define ARENA_H
+
+typedef enum {
+    ARENA_ZERO     = 1 << 0,
+    ARENA_SOFTFAIL = 1 << 1,
+} arena_flags_t;
+
+// More or less taken from https://nullprogram.com/blog/2023/09/27/
+typedef struct {
+    uint8_t *begin;
+    uint8_t *end;
+} arena_t;
+
+arena_t arena_create(ptrdiff_t capacity)
+{
+    arena_t a = {0};
+    a.begin = malloc(capacity);
+    a.end = a.begin ? a.begin + capacity : 0;
+    return a;
+}
+
+
+void *arena_alloc(arena_t *a, ptrdiff_t size, ptrdiff_t align, ptrdiff_t count, arena_flags_t flags)
+{
+    ptrdiff_t padding = -(uintptr_t)a->begin & (align - 1);
+    ptrdiff_t available = a->end - a->begin - padding;
+    if (available < 0 || count > available/size)
+    {
+        // TODO: Decide what to do on oom
+        if (flags & ARENA_SOFTFAIL)
+            return 0;
+        else
+            abort();
+    }
+    void *p = a->begin + padding;
+    a->begin += padding + count*size;
+    return flags & ARENA_ZERO ? p : memset(p, 0, count*size);
+}
+
+#define arena_reserve(arena, type, count, flags) (type *)arena_alloc(arena, sizeof(type), _Alignof(type), count, flags)
+
+#define KB 1024
+#define MB 1024*KB
+#define GB 1024*MB
+
+#endif

input.h

@@ -45,7 +45,7 @@ typedef enum {
 } mouse_keysym_t;
 
 #define IME_STR_MAX 200 // TODO: check if this limit is sensible
-#define KEYBOARD_KEY_TOTAL
+#define KEYBOARD_KEY_TOTAL 256
 
 typedef struct {
     uint8_t keyboard_state;               // mostly used to check if we are using the IME

wayland.c

@@ -20,6 +20,7 @@
 #include "zwp-text-input-unstable-v3-protocol.h"
 // common headers for platform layer and application layer
 #include "input.h"
+#include "arena.h"
 
 struct wl_compositor *compositor = NULL;
 struct wl_registry *registry = NULL;
@@ -48,6 +49,7 @@ struct xkb_keymap *xkb_keymap = NULL;
 EGLBoolean errcode = 0;
 bool running = true;
 input_t user_input = {};
+arena_t main_arena = {};
 
 char *egl_s(int code)
 {
@@ -192,7 +194,7 @@ void keymap_callback(void *data, struct wl_keyboard *kb, uint format, int fd, ui
     xkb_keymap = xkb_keymap_new_from_string(xkb_context, mem, XKB_KEYMAP_FORMAT_TEXT_V1, XKB_KEYMAP_COMPILE_NO_FLAGS);
     munmap(mem, size);
     close(fd);
-    
+
     if (!(xkb_state = xkb_state_new(xkb_keymap)))
         fprintf(stderr, "Could not initialize XKB state machine\n");
 }
@@ -205,9 +207,9 @@ void enter_callback(void *data, struct wl_keyboard* kb, uint serial, struct wl_s
     // NOTE: wl_array is a dynamic array as specified in wayland-util.h
     int32_t *pos = arr->data;
     // wl_keyboard is giving us all the currenly pressed keys anyways
-    for (int i = 0; i < KEYBOARD_KEY_TOTAL)
+    for (int i = 0; i < KEYBOARD_KEY_TOTAL; ++i)
         user_input.keys[i] = KEY_STATE_UNPRESSED;
-    
+
     wl_array_for_each(pos, arr) {
         xkb_keysym_t sym = xkb_state_key_get_one_sym(xkb_state, (*pos) + 8);
         // TODO: Decide if we should also set KEY_STATE_HELD
@@ -351,6 +353,11 @@ void pointer_axis_relative_direction_callback(void *data, struct wl_pointer *poi
 int main()
 {
     fprintf(stdout, "Starting platform layer...\n");
+    main_arena = arena_create(1*GB);
+    if (!main_arena.begin)
+        fprintf(stderr, "Could not reserve memory for main arena!\n");
+
+
     struct wl_display *display = wl_display_connect(NULL);
     if (!display)
     {
@@ -387,11 +394,11 @@ int main()
       .configure = xdg_toplevel_configure,
       .close = xdg_toplevel_close
     };
-    
+
     const struct xdg_wm_base_listener xdg_wm_base_listener = {
       .ping = wayland_ping
     };
-    
+
     if (xdg_toplevel_add_listener(xdg_toplevel, &xdg_toplevel_listener, NULL))
         fprintf(stderr, "Could not set XDG toplevel listener\n");
     if (xdg_wm_base_add_listener(wm_base, &xdg_wm_base_listener, NULL))
@@ -403,7 +410,7 @@ int main()
     }
     if (!(wl_pointer = wl_seat_get_pointer(wl_seat)))
         fprintf(stderr, "Could not get WL pointer\n");
-    
+
     if (!zwp_text_input_manager_v3)
         fprintf(stderr, "Could not get ZWP text input manager\n");
     else if (!(zwp_text_input_v3 = zwp_text_input_manager_v3_get_text_input(zwp_text_input_manager_v3, wl_seat)))
@@ -417,7 +424,7 @@ int main()
         .delete_surrounding_text = zwp_text_input_v3_delete_surrounding_text_callback,
         .done = zwp_text_input_v3_done_callback
     };
-    
+
     if (zwp_text_input_v3_add_listener(zwp_text_input_v3, &zwp_text_input_v3_listener, NULL))
         fprintf(stderr, "Could not add ZWP text input callback\n");
 
@@ -440,7 +447,7 @@ int main()
     };
     if (wl_keyboard_add_listener(wl_keyboard, &wl_keyboard_listener, NULL))
         fprintf(stderr, "Could not set XKB keyboard listener\n");
-    
+
     /* NOTE: Apparently wl_pointer added 'axis_value120' with v8 and 'axis_relative_direction' events with v9.
              Failing to provide callbacks for them crashes the client in runtime */
     const struct wl_pointer_listener wl_pointer_listener = {
@@ -478,7 +485,8 @@ int main()
     if (errcode != EGL_TRUE)
       fprintf(stderr, "ERR %s: Could not retrieve EGL config number\n", egl_s(errcode));
 
-    EGLConfig *configs = calloc(config_count, sizeof(EGLConfig));
+    //EGLConfig *configs = calloc(config_count, sizeof(EGLConfig));
+    EGLConfig *configs = arena_reserve(&main_arena, EGLConfig, config_count, ARENA_ZERO);
 
     EGLint attr_list[] = {
 	EGL_SURFACE_TYPE, EGL_WINDOW_BIT,