Fix up Cochran dive header decoding offset

[ext/subsurface.git] / cochran.c

diff --git a/cochran.c b/cochran.c
index 84bfcb96a775dff31f831536a990cd1dbb55ec13..ce42c3131276bec8e604e33631a507f0b3130f3f 100644 (file)
--- a/cochran.c
+++ b/cochran.c
@@ -79,7 +79,7 @@ static int figure_out_modulus(const unsigned char *decode, const unsigned char *
 
 #define hexchar(n) ("0123456789abcdef"[(n)&15])
 
-static void show_line(unsigned offset, const unsigned char *data, unsigned size)
+static int show_line(unsigned offset, const unsigned char *data, unsigned size, int show_empty)
 {
        unsigned char bits;
        int i, off;
@@ -105,18 +105,47 @@ static void show_line(unsigned offset, const unsigned char *data, unsigned size)
                asc[1] = 0;
        }
 
-       if (bits)
+       if (bits) {
                puts(buffer);
+               return 1;
+       }
+       if (show_empty)
+               puts("...");
+       return 0;
 }
 
-static void cochran_debug_write(const char *filename, int dive, const unsigned char *data, unsigned size)
+static void cochran_debug_write(const char *filename, const unsigned char *data, unsigned size)
 {
-       int i;
-       printf("\n%s, dive %d\n\n", filename, dive);
+       int i, show = 1;
 
-       for (i = 0; i < size; i += 16) {
-               show_line(i, data + i, size - i);
-       }
+       for (i = 0; i < size; i += 16)
+               show = show_line(i, data + i, size - i, show);
+}
+
+static void parse_cochran_header(const char *filename,
+               const unsigned char *decode, unsigned mod,
+               const unsigned char *in, unsigned size)
+{
+       char *buf = malloc(size);
+
+       /* Do the "null decode" using a one-byte decode array of '\0' */
+       partial_decode(0    , 0x0b14, "", 0, 1, in, size, buf);
+
+       /*
+        * The header scrambling is different form the dive
+        * scrambling. Oh yay!
+        */
+       partial_decode(0x010e, 0x0b14, decode, 0, mod, in, size, buf);
+       partial_decode(0x0b14, 0x1b14, decode, 0, mod, in, size, buf);
+       partial_decode(0x1b14, 0x2b14, decode, 0, mod, in, size, buf);
+       partial_decode(0x2b14, 0x3b14, decode, 0, mod, in, size, buf);
+       partial_decode(0x3b14, 0x5414, decode, 0, mod, in, size, buf);
+       partial_decode(0x5414,   size, decode, 0, mod, in, size, buf);
+
+       printf("\n%s, header\n\n", filename);
+       cochran_debug_write(filename, buf, size);
+
+       free(buf);
 }
 
 static void parse_cochran_dive(const char *filename, int dive,
@@ -146,9 +175,12 @@ 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, size, decode, 0, mod, in, size, buf);
+       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);
 
-       cochran_debug_write(filename, dive, buf, size);
+       printf("\n%s, dive %d\n\n", filename, dive);
+       cochran_debug_write(filename, buf, size);
 
        free(buf);
 }
@@ -170,6 +202,8 @@ int try_to_open_cochran(const char *filename, struct memblock *mem, GError **err
 
        mod = figure_out_modulus(decode, mem->buffer + dive1, dive2 - dive1);
 
+       parse_cochran_header(filename, decode, mod, mem->buffer + 0x40000, dive1 - 0x40000);
+
        for (i = 0; i < 65534; i++) {
                dive1 = offsets[i];
                dive2 = offsets[i+1];
@@ -177,7 +211,7 @@ int try_to_open_cochran(const char *filename, struct memblock *mem, GError **err
                        break;
                if (dive2 > mem->size)
                        break;
-               parse_cochran_dive(filename, i, decode, mod, mem->buffer + dive1, dive2 - dive1);
+               parse_cochran_dive(filename, i+1, decode, mod, mem->buffer + dive1, dive2 - dive1);
        }
 
        exit(0);