First cut at new feature: gzip streams.

* Makefile (OBJS): Conditionally include new gzio.o object file.

* configure: Detect external zlib, setting up new have_zlib
variable in config.make, HAVE_ZLIB in config.h, and also -lz
in conf_ldlibs.

* gzio.[ch]: New files, implementing the stream abstraction
over the gzip file I/O routines in zlib.

* stream.h (struct stdio_mode): New gzip flag and gzlevel
bitfield to hold a value 0 to 9.
(stdio_mode_init_blank, stdio_mode_init_r, stdio_mode_init_rpb):
Update intializers to cover new bitfield members.

* stream.c: Include <zlib.h> and "gzio.h" if HAVE_ZLIB.
(do_parse_mode): Recognize new mode modifier letter "z",
setting the gzip flag in the mode structure. If it's followed
by a digit, set the gziplevel to that value.
(format_mode): Don't output "b" letter for binary mode if
gzip is set, because gzopen interprets "b" differently.
Don't put out "t" if gzip is set. If gzip mode is specified,
do put out the level. If gzip is set, and gziplevel is nonzero
then encode the level: gzopen will understand it.
(open_file): If gzip mode is requested, then open the file
using gzopen mode, a new function in gzio.c. The return a
gzio stream based on the returned gzip file handle. However,
if we are reading, and the gzip stream indicates that it's
not decompressing anything, then we close it and open the
file using an ordinary stream.
(stream_init): Call gzio_init if HAVE_ZLIB is true. This is done
here because the module is integrated with stream.c, and also
so that lib.c doesn't have to know about HAVE_ZLIB and <zlib.h>.

1 files changed, 33 insertions, 0 deletions

diff --git a/gzio.h b/gzio.h
new file mode 100644
index 00000000..bbcd1e1a
--- /dev/null
+++ b/gzio.h
@@ -0,0 +1,33 @@
+/* Copyright 2022
+ * Kaz Kylheku <kaz@kylheku.com>
+ * Vancouver, Canada
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+val gzio_stream_s;
+void gzio_init(void);
+gzFile w_gzopen_mode(const wchar_t *wname, const wchar_t *wmode,
+                     const struct stdio_mode m, val self);
+val make_gzio_stream(gzFile f, int fd, val descr, int is_output);