From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Sat, 28 Jan 2012 02:27:30 +0000 (-0800)
Subject: Cochran: fix up dive data descrambling
X-Git-Url: http://git.tdb.fi/?a=commitdiff_plain;h=2d88353b5965853c01a9d394f96a5d0545d86b21;p=ext%2Fsubsurface.git

Cochran: fix up dive data descrambling

This seems to do the dive data descrambling right for both files I have
access to.  Except it uses a hardcoded (different) offset for the two.
I have yet to figure out how to automatically detect the offset itself
properly, so you have to compile for the right file.

I'll figure it out, but I'm committing this as a reasonable point in the
process.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/cochran.c b/cochran.c
index ce42c31..360f2eb 100644
--- a/cochran.c
+++ b/cochran.c
@@ -8,6 +8,8 @@
 #include "dive.h"
 #include "file.h"
 
+#define DON
+
 /*
  * The Cochran file format is designed to be annoying to read. It's roughly:
  *
@@ -153,6 +155,11 @@ static void parse_cochran_dive(const char *filename, int dive,
 		const unsigned char *in, unsigned size)
 {
 	char *buf = malloc(size);
+#ifdef DON
+	unsigned int offset = 0x4a14;
+#else
+	unsigned int offset = 0x4b14;
+#endif
 
 	/*
 	 * The scrambling has odd boundaries. I think the boundaries
@@ -175,9 +182,8 @@ static void parse_cochran_dive(const char *filename, int dive,
 	 * scrambled, but there seems to be size differences in the data,
 	 * so this just descrambles part of it:
 	 */
-	partial_decode(0x48ff, 0x4a14, decode, 0, mod, in, size, buf);
-	partial_decode(0x4a14, 0xc9bd, decode, 0, mod, in, size, buf);
-	partial_decode(0xc9bd,   size, decode, 0, mod, in, size, buf);
+	partial_decode(0x48ff, offset, decode, 0, mod, in, size, buf);
+	partial_decode(offset,   size, decode, 0, mod, in, size, buf);
 
 	printf("\n%s, dive %d\n\n", filename, dive);
 	cochran_debug_write(filename, buf, size);