First iteration of the skap tool for creating Asset Packs (#31)

tools/skap/src/skap.c

@@ -0,0 +1,68 @@
+/*
+ * GNU Sparky --- A 5v5 character-based libre tactical shooter
+ * Copyright (C) 2024 Wasym A. Alonso
+ *
+ * This file is part of Sparky.
+ *
+ * Sparky 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.
+ *
+ * Sparky 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 Sparky.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+#include <time.h>
+#include <stdio.h>
+#include <stdint.h>
+
+typedef uint8_t u8;
+typedef uint64_t u64;
+
+typedef struct {
+  char signature[4];
+  u8 fmt_ver;
+  u64 build_ver;
+} skap_header;
+
+static u64 concat_num(u64 x, u64 y) {
+  u64 n = 10;
+  while (y >= n) n *= 10;
+  return n * x + y;
+}
+
+static u64 compute_build_ver(void) {
+  time_t t = time(0);
+  struct tm *t_spec = localtime(&t);
+  u64 t_spec_arr[] = {
+    t_spec->tm_mon + 1,
+    t_spec->tm_mday,
+    t_spec->tm_hour,
+    t_spec->tm_min
+  };
+  u64 build_ver = t_spec->tm_year + 1900;
+  for (size_t i = 0; i < 4; ++i) {
+    if (t_spec_arr[i] < 10) build_ver *= 10;
+    build_ver = concat_num(build_ver, t_spec_arr[i]);
+  }
+  return build_ver;
+}
+
+int main(void) {
+  skap_header header = {
+    .signature = { 'S', 'K', 'A', 'P' },
+    .fmt_ver = 1,
+    .build_ver = compute_build_ver()
+  };
+  printf("header.signature => %s\n", header.signature);
+  printf("header.fmt_ver => %hhu\n", header.fmt_ver);
+  printf("header.build_ver => %ld\n", header.build_ver);
+  return 0;
+}