X-Git-Url: https://jxself.org/git/?a=blobdiff_plain;f=saveresume.c;h=f77925ab948649df9498957087d10cb217597e80;hb=7e21108e95aa0f745249720270247f7f69472d79;hp=d7fe76e5f3d9c79d69e87d57f9b1d082326d5ec0;hpb=f5ff25f52aaec53581d371c4d019af75c57fb989;p=open-adventure.git

diff --git a/saveresume.c b/saveresume.c
index d7fe76e..f77925a 100644
--- a/saveresume.c
+++ b/saveresume.c
@@ -19,35 +19,22 @@
 #include "dungeon.h"
 
 /*
- * Bump on save format change.
- *
- * Note: Verify that the tests run clean before bumping this, then rebuild the check
- * files afterwards.  Otherwise you will get a spurious failure due to the old version
- * having been generated into a check file.
+ * Use this to detect endianness mismatch.  Can't be unchanged by byte-swapping.
  */
-#define VRSION	29
+#define ENDIAN_MAGIC	2317
 
-/*
- * If you change the first three members, the resume function may not properly
- * reject saves from older versions. Later members can change, but bump the version
- * when you do that.
- */
-struct save_t {
-    int64_t savetime;
-    int32_t mode;		/* not used, must be present for version detection */
-    int32_t version;
-    struct game_t game;
-};
 struct save_t save;
 
 #define IGNORE(r) do{if (r){}}while(0)
 
-int savefile(FILE *fp, int32_t version)
+int savefile(FILE *fp)
 /* Save game to file. No input or output from user. */
 {
-    save.savetime = time(NULL);
-    save.mode = -1;
-    save.version = (version == 0) ? VRSION : version;
+    memcpy(&save.magic, ADVENT_MAGIC, sizeof(ADVENT_MAGIC));
+    if (save.version == 0)
+	save.version = SAVE_VERSION;
+    if (save.canary == 0)
+	save.canary = ENDIAN_MAGIC;
 
     save.game = game;
     IGNORE(fwrite(&save, sizeof(struct save_t), 1, fp));
@@ -105,7 +92,7 @@ int suspend(void)
         free(name);
     }
 
-    savefile(fp, VRSION);
+    savefile(fp);
     fclose(fp);
     rspeak(RESUME_HELP);
     exit(EXIT_SUCCESS);
@@ -156,8 +143,10 @@ int restore(FILE* fp)
 
     IGNORE(fread(&save, sizeof(struct save_t), 1, fp));
     fclose(fp);
-    if (save.version != VRSION) {
-        rspeak(VERSION_SKEW, save.version / 10, MOD(save.version, 10), VRSION / 10, MOD(VRSION, 10));
+    if (memcmp(save.magic, ADVENT_MAGIC, sizeof(ADVENT_MAGIC)) != 0 || save.canary != ENDIAN_MAGIC)
+	rspeak(BAD_SAVE);
+    else if (save.version != SAVE_VERSION) {
+        rspeak(VERSION_SKEW, save.version / 10, MOD(save.version, 10), SAVE_VERSION / 10, MOD(SAVE_VERSION, 10));
     } else if (!is_valid(save.game)) {
 	rspeak(SAVE_TAMPERING);
 	exit(EXIT_SUCCESS);