Experiment for TOC on overwriteables: Keep a target_head copy of session #1

libisoburn/isoburn.h

@@ -17,6 +17,18 @@
 /* for uint8_t */
 #include <stdint.h>
 
+/* For emulated TOC of overwriteable media.
+   Provides minimal info for faking a struct burn_toc_entry.
+*/
+struct isoburn_toc_entry {
+ int session;
+ int track_no; /* point */
+ int start_lba;
+ int track_blocks;
+
+ struct isoburn_toc_entry *next;
+};
+
 
 struct isoburn {
 
@@ -36,6 +48,11 @@ struct isoburn {
  struct isoburn *next;
 
 
+ /* The nwa to be used for a first session on the present kind of overwriteable
+    media (usually Libisoburn_overwriteable_starT, but might be forced to 0)
+  */
+ int zero_nwa;
+
  /* Start address as given by image examination (bytes, not blocks) */
  off_t min_start_byte;
 
@@ -51,6 +68,11 @@ struct isoburn {
  */
  enum burn_disc_status fabricated_disc_status;
 
+ /* Eventual emulated table of content read from the chain of ISO headers
+    on overwriteable media.
+ */ 
+ struct isoburn_toc_entry *toc;
+
 #ifndef Libisoburn_no_fifO
  /* The fifo which is installed between track and libisofs burn_source
  */
@@ -328,5 +350,34 @@ struct isoburn_imgen_opts {
     int effective_lba;
 };
 
+
+/* Alignment for session starts on overwriteable media.
+   (Increased from 16 to 32 blocks for aligning to BD-RE clusters.)
+*/
+#define Libisoburn_nwa_alignemenT 32
+
+/* Size of target_iso_head which is to be written during
+   isoburn_activate_session()
+*/
+#define Libisoburn_target_head_sizE (32*2048)
+
+/* >>> Experiment to create a chain of image headers which form a TOC:
+
+   The header of the first session is written after the LBA 0 header.
+   So it persists and can give the end of its session. By help of
+   Libisoburn_nwa_alignemenT it should be possible to predict the start
+   of the next session header.
+   The LBA 0 header is written by isoburn_activate_session() already
+   with the first session. So the media is mountable.
+   A problem arises with DVD-RW in Intermediate State. They cannot be
+   written by random access before they were written sequentially.
+   In this case, no copy of the session  1 header is maintained and no TOC
+   will be possible. Thus writing begins sequentially at LBA 0.
+*/
+#define Libisoburn_overwriteable_starT \
+                                   ((off_t) (Libisoburn_target_head_sizE/2048))
+
+
+
 #endif /* Isoburn_includeD */