From c91a9601af734b6463429308efa4908280f62cf4 Mon Sep 17 00:00:00 2001
From: Thomas Schmitt <scdbackup@gmx.net>
Date: Thu, 17 Jul 2008 18:29:50 +0000
Subject: [PATCH] Recognizing growisofs follow-up sessions on xorriso
 overwriteables

---
 libisoburn/trunk/libisoburn/burn_wrap.c      | 28 ++++++++++++++++++--
 libisoburn/trunk/xorriso/xorriso_timestamp.h |  2 +-
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/libisoburn/trunk/libisoburn/burn_wrap.c b/libisoburn/trunk/libisoburn/burn_wrap.c
index 7a780596..54832292 100644
--- a/libisoburn/trunk/libisoburn/burn_wrap.c
+++ b/libisoburn/trunk/libisoburn/burn_wrap.c
@@ -1036,7 +1036,7 @@ int isoburn_read_iso_head(struct burn_drive *d, int lba,
 int isoburn_emulate_toc(struct burn_drive *d, int flag)
 {
  int ret, image_size= 0, lba, track_blocks, session_count= 0, read_flag= 0;
- int scan_start= 0, scan_count= 0;
+ int scan_start= 0, scan_count= 0, probe_minus_16= 0, growisofs_nwa;
  struct isoburn *o;
  struct isoburn_toc_entry *item;
  char msg[160], size_text[80], *sev;
@@ -1073,7 +1073,23 @@ int isoburn_emulate_toc(struct burn_drive *d, int flag)
    }
    read_flag= 0;
    if(flag&2)
-     read_flag= (1<<15)|((session_count>0)<<14);
+     read_flag|= (1<<15)|((session_count>0)<<14);
+   else {
+
+     /* MULTI :
+        growisofs aligns to 16 rather than 32. Overwriteable TOC emulation
+        relies on not accidentially seeing inter-session trash data.
+        But one can safely access 16 blocks earlier because a xorriso header
+        would have overwritten with the unused 16 blocks at its start.
+        If libisoburn alignment would increase, then this would not be
+        possible any more.
+     */
+
+     if(probe_minus_16)
+       read_flag|= (1<<14);
+     probe_minus_16= 0;
+   }
+
    ret= isoburn_read_iso_head(d, lba, &track_blocks, NULL, read_flag);
    if(ret<=0) {
      if(session_count>0) {
@@ -1112,9 +1128,17 @@ int isoburn_emulate_toc(struct burn_drive *d, int flag)
    item->start_lba= lba;
    item->track_blocks= track_blocks;
    lba+= track_blocks;
+
+   /* MULTI : growisofs aligns to 16 rather than 32 */;
+
+   growisofs_nwa= lba;
+   if(growisofs_nwa % 16)
+     growisofs_nwa+= 16 - (growisofs_nwa % 16);
    if(lba % Libisoburn_nwa_alignemenT)
      lba+= Libisoburn_nwa_alignemenT - (lba % Libisoburn_nwa_alignemenT);
    scan_start= lba;
+   if(lba - growisofs_nwa == 16)
+     probe_minus_16= 1;
  }
  if(last_pacifier != start_time)
    sev= "UPDATE";
diff --git a/libisoburn/trunk/xorriso/xorriso_timestamp.h b/libisoburn/trunk/xorriso/xorriso_timestamp.h
index 47ddd4bf..38ac11bb 100644
--- a/libisoburn/trunk/xorriso/xorriso_timestamp.h
+++ b/libisoburn/trunk/xorriso/xorriso_timestamp.h
@@ -1 +1 @@
-#define Xorriso_timestamP "2008.07.17.111411"
+#define Xorriso_timestamP "2008.07.17.183024"