Keep track, in Wiretap, of whether the file is compressed, and provide

an API to fetch that.

When doing "Save" on a compressed file, write it out compressed.

In the Statistics -> Summary dialog and in capinfos, report whether the
file is gzip-compressed.

svn path=/trunk/; revision=42818

1 files changed, 5 insertions, 1 deletions

diff --git a/file.c b/file.c
index e04d4a4194..bfbc293ab1 100644
--- a/file.c
+++ b/file.c
@@ -530,6 +530,9 @@ cf_read(capture_file *cf, gboolean reloading)
   else
     cf_callback_invoke(cf_cb_file_read_started, cf);
 
+  /* Record whether the file is compressed. */
+  cf->iscompressed = wtap_iscompressed(cf->wth);
+
   /* Find the size of the file. */
   size = wtap_file_size(cf->wth, NULL);
 
@@ -3818,7 +3821,8 @@ cf_save_packets(capture_file *cf, const char *fname, guint save_format,
 
   cf_callback_invoke(cf_cb_file_save_started, (gpointer)fname);
 
-  if (save_format == cf->cd_t && !cf->unsaved_changes) {
+  if (save_format == cf->cd_t && compressed == cf->iscompressed
+      && !cf->unsaved_changes) {
     /* We're saving in the format it's already in, and there are no
        changes we have in memory that aren't saved to the file, so
        we can just move or copy the raw data. */