From a607da9373e4cbf8609fac477ef5ecd3323ca234 Mon Sep 17 00:00:00 2001
From: Thomas White <taw@physics.org>
Date: Tue, 11 Feb 2020 11:42:21 +0100
Subject: Don't use gzbuffer if it's not available

Enables compatability with zlib < 1.2.3.5
---
 libcrystfel/CMakeLists.txt    | 5 +++++
 libcrystfel/config.h.cmake.in | 1 +
 libcrystfel/src/image.c       | 2 ++
 3 files changed, 8 insertions(+)

diff --git a/libcrystfel/CMakeLists.txt b/libcrystfel/CMakeLists.txt
index 87b621b0..9f79b0c4 100644
--- a/libcrystfel/CMakeLists.txt
+++ b/libcrystfel/CMakeLists.txt
@@ -16,6 +16,11 @@ set(HAVE_XGANDALF ${XGANDALF_FOUND})
 set(HAVE_PINKINDEXER ${PINKINDEXER_FOUND})
 set(HAVE_FDIP ${FDIP_FOUND})
 
+# Recent enough version of zlib?
+set(CMAKE_REQUIRED_LIBRARIES "-lz")
+check_symbol_exists(gzbuffer "zlib.h" HAVE_GZBUFFER)
+unset(CMAKE_REQUIRED_LIBRARIES)
+
 # Find out where forkpty() is declared
 set(CMAKE_REQUIRED_LIBRARIES "-lutil")
 check_symbol_exists(forkpty "pty.h" HAVE_FORKPTY_PTY_H)
diff --git a/libcrystfel/config.h.cmake.in b/libcrystfel/config.h.cmake.in
index b7ad4c7a..20ae7399 100644
--- a/libcrystfel/config.h.cmake.in
+++ b/libcrystfel/config.h.cmake.in
@@ -8,6 +8,7 @@
 #cmakedefine HAVE_PINKINDEXER
 #cmakedefine HAVE_FDIP
 #cmakedefine HAVE_CURSES
+#cmakedefine HAVE_GZBUFFER
 
 #cmakedefine HAVE_FORKPTY_PTY_H
 #cmakedefine HAVE_FORKPTY_UTIL_H
diff --git a/libcrystfel/src/image.c b/libcrystfel/src/image.c
index 9768e15d..6358a9d0 100644
--- a/libcrystfel/src/image.c
+++ b/libcrystfel/src/image.c
@@ -787,8 +787,10 @@ static float *read_cbf_data(struct imagefile *f, int *w, int *h)
 		gzfh = gzopen(f->filename, "rb");
 		if ( gzfh == NULL ) return NULL;
 
+		#ifdef HAVE_GZBUFFER
 		/* Set larger buffer size for hopefully faster uncompression */
 		gzbuffer(gzfh, 128*1024);
+		#endif
 
 		buf = malloc(bufsz);
 		if ( buf == NULL ) return NULL;
-- 
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