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, 6 deletions

diff --git a/wiretap/csids.c b/wiretap/csids.c
index 23f97c5749..61722f6dcb 100644
--- a/wiretap/csids.c
+++ b/wiretap/csids.c
@@ -136,7 +136,6 @@ int csids_open(wtap *wth, int *err, gchar **err_info)
   if (file_seek(wth->fh, 0, SEEK_SET, err) == -1)
     return -1;
 
-  wth->data_offset = 0;
   csids = (csids_t *)g_malloc(sizeof(csids_t));
   wth->priv = (void *)csids;
   csids->byteswapped = byteswap;
@@ -159,7 +158,7 @@ static gboolean csids_read(wtap *wth, int *err, gchar **err_info,
   int bytesRead = 0;
   struct csids_header hdr;
 
-  *data_offset = wth->data_offset;
+  *data_offset = file_tell(wth->fh);
 
   bytesRead = file_read( &hdr, sizeof( struct csids_header) , wth->fh );
   if( bytesRead != sizeof( struct csids_header) ) {
@@ -171,8 +170,6 @@ static gboolean csids_read(wtap *wth, int *err, gchar **err_info,
   hdr.seconds = pntohl(&hdr.seconds);
   hdr.caplen = pntohs(&hdr.caplen);
 
-  wth->data_offset += sizeof( struct csids_header );
-
   /* Make sure we have enough room for the packet */
   buffer_assure_space(wth->frame_buffer, hdr.caplen);
   buf = buffer_start_ptr(wth->frame_buffer);
@@ -185,8 +182,6 @@ static gboolean csids_read(wtap *wth, int *err, gchar **err_info,
     return FALSE;
   }
 
-  wth->data_offset += hdr.caplen;
-
   wth->phdr.presence_flags = WTAP_HAS_TS;
   wth->phdr.len = hdr.caplen;
   wth->phdr.caplen = hdr.caplen;