file_seek() used to be a wrapper around fseek() or gzseek(), both of

which could use lseek() and were thus expensive due to system call
overhead.  To avoid making a system call for every packet on a
sequential read, we maintained a data_offset field in the wtap structure
for sequential reads.

It's now a routine that just returns information from the FILE_T data
structure, so it's cheap.  Use it, rather than maintaining the data_offset
field.

Readers for some file formats need to maintain file offset themselves;
have them do so in their private data structures.

svn path=/trunk/; revision=42423

1 files changed, 1 insertions, 4 deletions

diff --git a/wiretap/k12.c b/wiretap/k12.c
index a4cbf0c417..7be553aafb 100644
--- a/wiretap/k12.c
+++ b/wiretap/k12.c
@@ -410,7 +410,7 @@ static gboolean k12_read(wtap *wth, int *err, gchar **err_info, gint64 *data_off
     guint64 ts;
     guint32 extra_len;
 
-    offset = wth->data_offset;
+    offset = file_tell(wth->fh);
 
     /* ignore the record if it isn't a packet */
     do {
@@ -448,8 +448,6 @@ static gboolean k12_read(wtap *wth, int *err, gchar **err_info, gint64 *data_off
 
     } while ( ((type & K12_MASK_PACKET) != K12_REC_PACKET) || !src_id || !src_desc );
 
-    wth->data_offset = offset;
-
     wth->phdr.presence_flags = WTAP_HAS_TS;
 
     ts = pntohll(buffer + K12_PACKET_TIMESTAMP);
@@ -815,7 +813,6 @@ int k12_open(wtap *wth, int *err, gchar **err_info) {
         }
     } while(1);
 
-    wth->data_offset = offset;
     wth->file_type = WTAP_FILE_K12;
     wth->file_encap = WTAP_ENCAP_K12;
     wth->snapshot_length = 0;