1 /*
   2  * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 /*
  27  * This header file is used to hijack the include of "zlib.h" from libpng on
  28  * Macos. We do that to be able to build on macos 10.13 or later, but still
  29  * keep binary compatibility with older versions (as specified to configure).
  30  *
  31  * The problem is that in 10.13, Macos shipped with a newer version of zlib,
  32  * which exports the function inflateValidate. There is a call to this
  33  * function in pngrutil.c, guarded by a preprocessor check of ZLIB_VERNUM being
  34  * high enough. If we compile this call in and link to the newer version of
  35  * zlib, we will get link errors if the code is executed on an older Mac with
  36  * an older version of zlib.
  37  *
  38  * The zlib.h header in Macos has been annotated with Macos specific macros that
  39  * guard these kinds of version specific APIs, but libpng is not using those
  40  * checks in its conditionals, just ZLIB_VERNUM. To fix this, we check for the
  41  * MAC_OS_X_VERSION_MIN_REQUIRED macro here and adjust the ZLIB_VERNUM to the
  42  # known version bundled with that release. This solution is certainly a hack,
  43  * but it seems the affected versions of zlib.h are compatible enough for this
  44  * to work.
  45  */
  46 
  47 #include <zlib.h>
  48 #include <AvailabilityMacros.h>
  49 
  50 #if MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_12
  51 #  undef ZLIB_VERNUM
  52 #  define ZLIB_VERNUM 0x1250
  53 #elif MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_13
  54 #  undef ZLIB_VERNUM
  55 #  define ZLIB_VERNUM 0x1280
  56 #endif