Adopted new libisofs filter module gzip.c, builtin filters --gzip, --gunzip

xorriso/xorriso.1

@@ -2,7 +2,7 @@
 .\" First parameter, NAME, should be all caps
 .\" Second parameter, SECTION, should be 1-8, maybe w/ subsection
 .\" other parameters are allowed: see man(7), man(1)
-.TH XORRISO 1 "Apr 13, 2009"
+.TH XORRISO 1 "Apr 14, 2009"
 .\" Please adjust this date whenever revising the manpage.
 .\"
 .\" Some roff macros, for reference:
@@ -1117,13 +1117,13 @@ files which currently have the filter applied.
 .br
 Examples:
 .br
- -external_filter gzip suffix=.gz:if_block_reduction \\
+ -external_filter bzip2 suffix=.bz2:if_block_reduction \\
 .br
-                  /usr/bin/gzip --
+                  /usr/bin/bzip2 --
 .br
- -external_filter gunzip suffix=.gz:remove_suffix:if_nonempty \\
+ -external_filter bunzip2 suffix=.bz2:remove_suffix:if_nonempty \\
 .br
-                  /usr/bin/gunzip --
+                  /usr/bin/bunzip2 --
 .TP
 \fB\-unregister_filter\fR name
 Remove an -external_filter registration. This is only possible if the filter
@@ -1165,6 +1165,10 @@ prevent any suffix renaming.
 Builtin filters are "--zisofs" and "--zisofs-decode". The former is to be
 applied via -set_filter, the latter is automatically applied if zisofs
 compressed content is detected with a file when loading the ISO image.
+.br
+Another builtin filter pair is "--gzip" and "--gunzip" with suffix ".gz".
+They behave about like external gzip and gunzip but avoid forking a process
+for each single file. So they are much faster if there are many small files.
 .TP
 \fB\-set_filter_r\fR name isuffix iso_rr_path [***]
 Like -set_filter but affecting all data files below eventual directories.