Enabled multi-session with partition offset

libisoburn/isoburn.h

@@ -36,20 +36,15 @@ int isoburn_toc_entry_new(struct isoburn_toc_entry **objpt,
 int isoburn_toc_entry_destroy(struct isoburn_toc_entry **o, int flag);
 
 
-/* >>> TWINTREE : provisory test of partition offset with emulated TOC.
-                  .target_iso_head must become dynamically allocated
-#define Libisoburn_partition_offseT 16
+/* Minimal size of target_iso_head which is to be written during
+   isoburn_activate_session().
+   TWINTREE:
+   Within this size there is everything that is needed for image access with
+   no partition offset. The actual target_iso_head buffer must be larger by
+   the evential partition offset.
 */
-
-
-/* Size of target_iso_head which is to be written during
-   isoburn_activate_session()
-*/
-#ifdef Libisoburn_partition_offseT
-#define Libisoburn_target_head_sizE (32*2048 +Libisoburn_partition_offseT*2048)
-#else
 #define Libisoburn_target_head_sizE (32*2048)
-#endif
+
 
 struct isoburn {
 
@@ -114,9 +109,14 @@ struct isoburn {
  int wrote_well;
 
  
- /* Buffered ISO head from media (should that become part of
-    ecma119_read_opts ?) */
- uint8_t target_iso_head[Libisoburn_target_head_sizE];
+ /* ISO head buffer to be filled by write run */
+ int target_iso_head_size;
+ uint8_t *target_iso_head;
+
+ /* The 2k offset which was read from a loaded image.
+ */
+ uint32_t loaded_partition_offset;
+ 
 
  /* Libisofs image context */
  IsoImage *image;
@@ -253,6 +253,13 @@ isoburn_data_source_new(struct burn_drive *d);
 int isoburn_data_source_shutdown(IsoDataSource *src, int flag);
 
 
+/** TWINTREE:
+    Check whether size of target_iso_head matches offset.
+    Eventually adjust size.
+*/
+int isoburn_adjust_target_iso_head(struct isoburn *o,
+                                   uint32_t offst, int flag);
+
 /**
  * Options for image reading.
    (Comments here may be outdated. API getter/setter function descriptions
@@ -576,6 +583,10 @@ struct isoburn_imgen_opts {
    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.
+
+   TWINTREE:
+   This macro gives the minimal size of an image header. It has to be
+   enlarged by the eventual partition offset.
 */
 #define Libisoburn_overwriteable_starT \
                                    ((off_t) (Libisoburn_target_head_sizE/2048))