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, 2 deletions

diff --git a/wiretap/mpeg.c b/wiretap/mpeg.c
index fc7f126a6e..321f45a69a 100644
--- a/wiretap/mpeg.c
+++ b/wiretap/mpeg.c
@@ -225,13 +225,12 @@ mpeg_read(wtap *wth, int *err, gchar **err_info, gint64 *data_offset)
 				return FALSE;
 		}
 	}
-	*data_offset = wth->data_offset;
+	*data_offset = file_tell(wth->fh);
 
 	buffer_assure_space(wth->frame_buffer, packet_size);
 	if (!mpeg_read_rec_data(wth->fh, buffer_start_ptr(wth->frame_buffer),
 				packet_size, err, err_info))
 		return FALSE;
-	wth->data_offset += packet_size;
 	/* XXX - relative, not absolute, time stamps */
 	wth->phdr.presence_flags = WTAP_HAS_TS;
 	wth->phdr.ts = ts;