Define a display interface

2 files changed, 100 insertions, 0 deletions

diff --git a/src/disp.c b/src/disp.c
new file mode 100644
index 0000000..f3448ae
--- /dev/null
+++ b/src/disp.c
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2024  Tristan Riehs
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include "config.h"
+
+#include <dlfcn.h>
+#include <string.h>
+#include <stdlib.h>
+#include <assert.h>
+
+#include "disp.h"
+
+#define dlsym_and_check(dest, name)		\
+	dest->name = dlsym(dest->dl_handle, #name);	\
+	if (!dest->name) {				\
+		dlclose(dest->dl_handle);		\
+		free(dest);				\
+		return NULL;				\
+	}
+
+struct disp *
+get_disp(char *disp_name)
+{
+#ifndef NDEBUG
+	/* displays are shared libraries */
+	char so_path[16] = {0};
+	strcpy(so_path, "./");
+	strcat(so_path, disp_name);
+	strcat(so_path, ".la");
+	void *handle = dlopen(so_path, RTLD_LAZY);
+
+	if (!handle)
+		return NULL;
+
+	struct disp *disp = malloc(sizeof(*disp));
+	disp->dl_handle = handle;
+	dlsym_and_check(disp, display_calc);
+	dlsym_and_check(disp, read_input);
+	dlsym_and_check(disp, display_res);
+	dlsym_and_check(disp, destroy);
+
+	return disp;
+#else
+#  error "not available yet"
+#endif
+	return NULL;
+}
diff --git a/src/disp.h b/src/disp.h
new file mode 100644
index 0000000..e011884
--- /dev/null
+++ b/src/disp.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2024  Tristan Riehs
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef DISP_H
+#define DISP_H
+
+#include <stdbool.h>
+
+/* Available display types. */
+#define DISP_CLI "cli"
+#define DISP_RAY "ray"
+
+struct disp {
+	void *dl_handle;
+	void (*init)(void);
+	void (*display_calc)(int, int);
+	int  (*read_input)(void);
+	void (*display_res)(bool, int);
+	void (*destroy)(void);
+};
+
+/* Get a display handler for the given display type. */
+struct disp *get_disp(char *disp_name);
+
+void destroy_disp(void);
+
+#endif