Avoided to convert empty PVD components copyright_file_id, abstract_file_id, or

bibliographic_file_id to " " and then "_" during multi-session loading and
writing. New util function iso_util_strcopy_untail().

libisofs/fs_image.c

@@ -2133,9 +2133,12 @@ int read_pvm(_ImageFsData *data, uint32_t block)
     data->data_preparer_id = strcopy((char*)pvm->data_prep_id, 128);
     data->system_id = strcopy((char*)pvm->system_id, 32);
     data->application_id = strcopy((char*)pvm->application_id, 128);
-    data->copyright_file_id = strcopy((char*)pvm->copyright_file_id, 37);
+    data->copyright_file_id =
-    data->abstract_file_id = strcopy((char*)pvm->abstract_file_id, 37);
+               iso_util_strcopy_untail((char*) pvm->copyright_file_id, 37);
-    data->biblio_file_id = strcopy((char*)pvm->bibliographic_file_id, 37);
+    data->abstract_file_id =
+               iso_util_strcopy_untail((char*) pvm->abstract_file_id, 37);
+    data->biblio_file_id =
+               iso_util_strcopy_untail((char*) pvm->bibliographic_file_id, 37);
 
     data->nblocks = iso_read_bb(pvm->vol_space_size, 4, NULL);
 

libisofs/util.c

@@ -1392,13 +1392,36 @@ char *strcopy(const char *buf, size_t len)
     strncpy(str, buf, len);
     str[len] = '\0';
     
-    /* remove trailing spaces */
+    /* remove trailing spaces
+       (This leaves the space at str[0] existing. Bug or feature ?)
+    */
     for (len = len-1; str[len] == ' ' && len > 0; --len)
         str[len] = '\0'; 
     
     return str;
 }
 
+char *iso_util_strcopy_untail(const char *buf, size_t len)
+{
+    char *str;
+    
+    str = malloc((len + 1) * sizeof(char));
+    if (str == NULL) {
+        return NULL;
+    }
+    strncpy(str, buf, len);
+    str[len] = 0;
+    
+    /* remove trailing spaces */
+    for (len = len-1; len >= 0; --len) {
+        if (str[len] != ' ')
+    break;
+        str[len] = 0; 
+    }
+    
+    return str;
+}
+
 /**
  * Copy up to \p max characters from \p src to \p dest. If \p src has less than
  * \p max characters, we pad dest with " " characters.

libisofs/util.h

@@ -249,9 +249,19 @@ int iso_eaccess(const char *path);
 /**
  * Copy up to \p len chars from \p buf and return this newly allocated
  * string. The new string is null-terminated.
+ * Note:
+ * Trailing blanks will be removed. But the first one of an all blank string
+ * persists. It is unclear whether this is a bug or a feature.
  */
 char *strcopy(const char *buf, size_t len);
 
+/**
+ * Copy up to \p len chars from \p buf and return this newly allocated
+ * string. The new string is null-terminated.
+ * Any trailing blanks will be removed.
+ */
+char *iso_util_strcopy_untail(const char *buf, size_t len);
+
 /**
  * Copy up to \p max characters from \p src to \p dest. If \p src has less than
  * \p max characters, we pad dest with " " characters.