Added highscore functionality

src/highscore.c

@@ -0,0 +1,75 @@
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include "engine.h"
+
+const char *hs_dir_name  = "2048";
+const char *hs_file_name = "highscore";
+
+static const char* highscore_retrieve_file(void)
+{
+    static char buffer[4096];
+
+    if (getenv("XDG_DATA_HOME") != NULL) {
+        snprintf(buffer, sizeof(buffer), "%s/%s/%s",
+                getenv("XDG_DATA_HOME"), hs_dir_name, hs_file_name);
+    }
+    else if (getenv("HOME")) {
+        snprintf(buffer, sizeof(buffer), "%s/.local/share/%s/%s",
+                getenv("HOME"), hs_dir_name, hs_file_name);
+    }
+    else {
+        return hs_file_name;
+    }
+
+    /* Create file only if it doesn't exist */
+    if (access(buffer, F_OK) != -1)
+        return buffer;
+
+    char *sep = strrchr(buffer, '/');
+    while (sep != NULL) {
+        *sep = '\0';
+        if (strlen(buffer) != 0)
+            mkdir(buffer, 0777);
+        char *tmpsep = sep;
+        sep = strrchr(buffer, '/');
+        *tmpsep = '/';
+    }
+
+    return buffer;
+}
+
+void highscore_reset(void)
+{
+    const char *hsfile = highscore_retrieve_file();
+
+    FILE *fd = fopen(hsfile, "w+");
+    fprintf(fd, "%d", 0);
+    fclose(fd);
+}
+
+void highscore_load(struct gamestate *g)
+{
+    const char *hsfile = highscore_retrieve_file();
+
+    FILE *fd = fopen(hsfile, "r");
+    if (fd == NULL)
+        fd = fopen(hsfile, "w+");
+
+    fscanf(fd, "%ld", &g->score_high);
+    fclose(fd);
+}
+
+void highscore_save(struct gamestate *g)
+{
+    if (g->score < g->score_high || g->opts->grid_width != 4 || g->opts->grid_height != 4)
+        return;
+
+    const char *hsfile = highscore_retrieve_file();
+
+    FILE *fd = fopen(hsfile, "w");
+    fprintf(fd, "%ld", g->score);
+    fclose(fd);
+}