Improve const use in zlib-using code

If we define ZLIB_CONST before including zlib.h, zlib augments some
interfaces with const decorations.  By doing that we can keep our own
interfaces cleaner and can remove some unconstify calls.

ZLIB_CONST was introduced in zlib 1.2.5.2 (17 Dec 2011).  When
compiling with older zlib releases, you might now get compiler
warnings about discarding qualifiers.

CentOS 6 has zlib 1.2.3, but in 8e278b6576, we removed support for the
OpenSSL release in CentOS 6, so it seems ok to de-support the zlib
release in CentOS 6 as well.

Reviewed-by: Tristan Partin <tristan@neon.tech>
Discussion: https://www.postgresql.org/message-id/flat/33462926-bb1e-7cc9-8d92-d86318e8ed1d%40eisentraut.org
This commit is contained in:
Peter Eisentraut 2023-08-07 09:06:52 +02:00
parent fdd79d8992
commit 67c0ef9752
4 changed files with 9 additions and 5 deletions

View File

@ -113,7 +113,7 @@ compress_process(PushFilter *next, void *priv, const uint8 *data, int len)
/* /*
* process data * process data
*/ */
st->stream.next_in = unconstify(uint8 *, data); st->stream.next_in = data;
st->stream.avail_in = len; st->stream.avail_in = len;
while (st->stream.avail_in > 0) while (st->stream.avail_in > 0)
{ {

View File

@ -269,7 +269,7 @@ bbstreamer_gzip_decompressor_content(bbstreamer *streamer,
mystreamer = (bbstreamer_gzip_decompressor *) streamer; mystreamer = (bbstreamer_gzip_decompressor *) streamer;
zs = &mystreamer->zstream; zs = &mystreamer->zstream;
zs->next_in = (uint8 *) data; zs->next_in = (const uint8 *) data;
zs->avail_in = len; zs->avail_in = len;
/* Process the current chunk */ /* Process the current chunk */

View File

@ -705,7 +705,7 @@ typedef struct TarMethodData
#ifdef HAVE_LIBZ #ifdef HAVE_LIBZ
static bool static bool
tar_write_compressed_data(TarMethodData *tar_data, void *buf, size_t count, tar_write_compressed_data(TarMethodData *tar_data, const void *buf, size_t count,
bool flush) bool flush)
{ {
tar_data->zp->next_in = buf; tar_data->zp->next_in = buf;
@ -782,8 +782,7 @@ tar_write(Walfile *f, const void *buf, size_t count)
#ifdef HAVE_LIBZ #ifdef HAVE_LIBZ
else if (f->wwmethod->compression_algorithm == PG_COMPRESSION_GZIP) else if (f->wwmethod->compression_algorithm == PG_COMPRESSION_GZIP)
{ {
if (!tar_write_compressed_data(tar_data, unconstify(void *, buf), if (!tar_write_compressed_data(tar_data, buf, count, false))
count, false))
return -1; return -1;
f->currpos += count; f->currpos += count;
return count; return count;

View File

@ -75,6 +75,11 @@
#include <libintl.h> #include <libintl.h>
#endif #endif
/* Define before including zlib.h to add const decorations to zlib API. */
#ifdef HAVE_LIBZ
#define ZLIB_CONST
#endif
/* ---------------------------------------------------------------- /* ----------------------------------------------------------------
* Section 1: compiler characteristics * Section 1: compiler characteristics