New API call iso_write_opts_set_high_empty_address().

libisofs/ecma119.c

@@ -380,11 +380,14 @@ void write_one_dir_record(Ecma119Image *t, Ecma119Node *node, int file_id,
         multi_extend = (node->info.file->nsections - 1 == extent) ? 0 : 1;
     } else {
         /*
-         * for nodes other than files and dirs, we set both
-         * len and block to 0
+         * for nodes other than files and dirs, we set len to 0, and
+         * the content block address to a dummy value.
          */
         len = 0;
-        block = 0;
+        if (t->high_empty_address)
+            block = t->empty_file_block;
+        else
+            block = 0;
     }
 
     /*
@@ -1577,6 +1580,7 @@ int ecma119_image_new(IsoImage *src, IsoWriteOpts *opts, Ecma119Image **img)
     target->hardlinks = opts->hardlinks;
     target->aaip = opts->aaip;
     target->always_gmt = opts->always_gmt;
+    target->high_empty_address = opts->high_empty_address;
     target->untranslated_name_len = opts->untranslated_name_len;
     target->allow_dir_id_ext = opts->allow_dir_id_ext;
     target->omit_version_numbers = opts->omit_version_numbers
@@ -1922,8 +1926,15 @@ int ecma119_image_new(IsoImage *src, IsoWriteOpts *opts, Ecma119Image **img)
         if (i == el_torito_writer_index)
     continue;
 
-        /* Exposing address of data start to IsoWriteOpts */
+        /* Exposing address of data start to IsoWriteOpts iand memorizing
+           this address for for all files which have no block address: 
+           symbolic links, device files, empty data files.
+           filesrc_writer_compute_data_blocks() and filesrc_writer_write_data()
+           will account resp. write this single block. 
+        */
         if (i == file_src_writer_index) {
+            if (target->high_empty_address)
+                target->empty_file_block = target->curblock;
             opts->data_start_lba = target->curblock;
         }
 
@@ -2368,6 +2379,7 @@ int iso_write_opts_new(IsoWriteOpts **opts, int profile)
     wopts->ascii_disc_label[0] = 0;
     wopts->will_cancel = 0;
     wopts->allow_dir_id_ext = 0;
+    wopts->high_empty_address = 0;
     wopts->untranslated_name_len = 0;
 
     *opts = wopts;
@@ -2457,6 +2469,15 @@ int iso_write_opts_set_aaip(IsoWriteOpts *opts, int enable)
     return ISO_SUCCESS;
 }
 
+int iso_write_opts_set_high_empty_address(IsoWriteOpts *opts, int enable)
+{
+    if (opts == NULL) {
+        return ISO_NULL_POINTER;
+    }
+    opts->high_empty_address = enable ? 1 : 0;
+    return ISO_SUCCESS;
+}
+
 int iso_write_opts_set_untranslated_name_len(IsoWriteOpts *opts, int len)
 {
     if (opts == NULL) {

libisofs/ecma119.h

@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2007 Vreixo Formoso
- * Copyright (c) 2009 Thomas Schmitt
+ * Copyright (c) 2009 - 2011 Thomas Schmitt
  *
  * This file is part of the libisofs project; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License version 2 
@@ -244,6 +244,16 @@ struct iso_write_opts {
     uid_t uid; /** uid to use when replace_uid == 2. */
     gid_t gid; /** gid to use when replace_gid == 2. */
 
+    /**
+     * Let symbolic links, device files, and empty data files point to
+     * a block address after the end of the directory tree, rather than
+     * using LBA 0 for links and devices, and the address of the Volume
+     * Descriptor Set Terminator for empty data files.
+     * Single-pass reader libarchive sorts by ths address and needs to see all
+     * directory info before processing any data files.
+     */ 
+    unsigned int high_empty_address :1;
+
     /**
      * Extra Caution: This option breaks any assumptions about names that
      *                are supported by ECMA-119 specifications. 
@@ -485,6 +495,7 @@ struct ecma119_image
     mode_t dir_mode;
     time_t timestamp;
 
+    unsigned int high_empty_address :1;
     unsigned int untranslated_name_len;
 
     /**

libisofs/filesrc.c

@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2007 Vreixo Formoso
- *               2010 Thomas Schmitt
+ *               2010 - 2011 Thomas Schmitt
  *
  * This file is part of the libisofs project; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License version 2 
@@ -232,6 +232,12 @@ int filesrc_writer_compute_data_blocks(IsoImageWriter *writer)
 
     t = writer->target;
 
+    /* Eventually reserve a single zeroed block for all files which have
+       no block address: symbolic links, device files, empty data files.
+    */
+    if (t->high_empty_address)
+        t->curblock++;
+
     /* on appendable images, ms files shouldn't be included */
     if (t->appendable) {
         inc_item = is_ms_file;
@@ -347,11 +353,22 @@ int filesrc_writer_write_data(IsoImageWriter *writer)
         return ISO_ASSERT_FAILURE;
     }
 
+    memset(buffer, 0, BLOCK_SIZE);
     t = writer->target;
     filelist = writer->data;
 
     iso_msg_debug(t->image->id, "Writing Files...");
 
+    /* Eventually write a single zeroed block as block address target for all
+       files which have no block address:
+       symbolic links, device files, empty data files.
+    */
+    if (t->high_empty_address) {
+        ret = iso_write(t, buffer, BLOCK_SIZE);
+        if (ret < 0)
+            goto ex;
+    }
+
     i = 0;
     while ((file = filelist[i++]) != NULL) {
         was_error = 0;

libisofs/libisofs.h

@@ -1370,6 +1370,24 @@ int iso_write_opts_set_hardlinks(IsoWriteOpts *opts, int enable);
  */
 int iso_write_opts_set_aaip(IsoWriteOpts *opts, int enable);
 
+/**
+ * Let symbolic links, device files, and empty data files point to a
+ * dedicated block of zero bytes after the end of the directory trees, rather
+ * than using address 0 for links and device files, resp. the address of the
+ * Volume Descriptor Set Terminator for empty data files.
+ * (Single-pass reader libarchive sorts by this address and needs to see all
+ *  directory info before processing any data files.)
+ *
+ * @param opts
+ *      The option set to be manipulated.
+ * @param enable
+ *      1 = use the address of a block after the directory tree.
+ *      0 = use the traditional block addresses in the range of 0 to 31.
+ *
+ * @since 1.0.2
+ */
+int iso_write_opts_set_high_empty_address(IsoWriteOpts *opts, int enable);
+
 /**
  * Caution: This option breaks any assumptions about names that
  *          are supported by ECMA-119 specifications. 

libisofs/libisofs.ver

@@ -274,6 +274,7 @@ iso_write_opts_set_dir_rec_mtime;
 iso_write_opts_set_disc_label;
 iso_write_opts_set_fifo_size;
 iso_write_opts_set_hardlinks;
+iso_write_opts_set_high_empty_address;
 iso_write_opts_set_iso1999;
 iso_write_opts_set_iso_level;
 iso_write_opts_set_joliet;