Clean up scorefile handling.

This was writing time_t to disk. Worse, the time_t member was at an
unaligned offset in the structure in question, so after the time_t
change the structure layout depended on compiler-inserted structure
padding. This gives three legacy formats: one with 32-bit time, one
with 64-bit time, and one with 64-bit time and 4 bytes of structure
padding.

And of course the file didn't have a header or version coding or
anything.

The new code writes a structure of well-defined size that should not
receive unexpected padding, and gives the file a header and version
number. It reads that format and any of the three legacy formats,
figuring out which one it's dealing with by inspecting the file
contents. For good measure, it also now handles opposite-endian files,
doesn't bail out unceremoniously unless necessary, and won't croak if
the file is corrupt and e.g. contains unterminated strings.

(Was it worth going to this length? Maybe not. But it didn't seem
right to just leave it, and it's not clear where to stop halfway.)

1 files changed, 36 insertions, 1 deletions

diff --git a/tetris/scores.h b/tetris/scores.h
index 2a5baa4f..2d72aec8 100644
--- a/tetris/scores.h
+++ b/tetris/scores.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: scores.h,v 1.4 2004/01/27 20:30:30 jsm Exp $	*/
+/*	$NetBSD: scores.h,v 1.5 2009/05/25 08:33:57 dholland Exp $	*/
 
 /*-
  * Copyright (c) 1992, 1993
@@ -37,6 +37,41 @@
 /*
  * Tetris scores.
  */
+
+/* Header for high score file. */
+#define HSH_MAGIC_SIZE 8
+struct highscore_header {
+	char hsh_magic[HSH_MAGIC_SIZE];
+	uint32_t hsh_endiantag;
+	uint32_t hsh_version;
+};
+
+/* Current on-disk high score record. */
+struct highscore_ondisk {
+	char hso_name[20];
+	int32_t hso_score;
+	int32_t hso_level;
+	int32_t hso_pad;
+	int64_t hso_time;
+};
+
+/* 5.99.x after time_t change, on 32-bit machines */
+struct highscore_ondisk_599 {
+	char hso599_name[20];
+	int32_t hso599_score;
+	int32_t hso599_level;
+	int32_t hso599_time[2];
+};
+
+/* 5.0 and earlier on-disk high score record. */
+struct highscore_ondisk_50 {
+	char hso50_name[20];
+	int32_t hso50_score;
+	int32_t hso50_level;
+	int32_t hso50_time;
+};
+
+/* In-memory high score record. */
 struct highscore {
 	char	hs_name[20];	/* login name */
 	int	hs_score;	/* raw score */