From: Simon McVittie <smcv@debian.org>
Date: Thu, 2 Apr 2015 10:31:53 +0100
Subject: Add support for DP_LINK_PNG=shared (default is dlopen)

Like the existing DP_LINK_TO_JPEG, this can be configured to
link libpng in the normal way instead of dlopening it.

Origin: vendor, Debian
Forwarded: no
---
 image_png.c  | 112 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 makefile     |  15 ++++++++
 makefile.inc |   4 +--
 3 files changed, 124 insertions(+), 7 deletions(-)

diff --git a/image_png.c b/image_png.c
index 6f52914..6e52f49 100644
--- a/image_png.c
+++ b/image_png.c
@@ -26,10 +26,80 @@
 //
 //LordHavoc: rewrote most of this.
 
+#ifdef LINK_TO_PNG
+// This has to come before anything else that includes setjmp.h, because
+// libpng specifically wants non-BSD setjmp semantics.
+// quakedef.h includes setjmp.h, but pngconf.h insists that on Linux,
+// setjmp.h has not already been included.
+//
+// Depending whether _BSD_SOURCE is preferred, glibc will provide one of two
+// implementations of setjmp()/longjmp() (it either does or doesn't save the
+// signal mask), acting on different definitions of the jmp_buf struct.
+# include <png.h>
+
+// libpng calls longjmp() internally, and expects its callers to call the
+// version of setjmp() corresponding to the longjmp() call that libpng would
+// make. Set this up before including any other headers that might
+// change which flavour of setjmp() we get.
+static inline int
+my_setjmp (jmp_buf env)
+{
+	return setjmp (env);
+}
+#endif
+
 #include "quakedef.h"
 #include "image.h"
 #include "image_png.h"
 
+#ifdef LINK_TO_PNG
+
+#define qpng_setjmp(png) my_setjmp (png_jmpbuf (png))
+
+#define qpng_set_sig_bytes png_set_sig_bytes
+#define qpng_sig_cmp png_sig_cmp
+#define qpng_create_read_struct png_create_read_struct
+#define qpng_create_write_struct png_create_write_struct
+#define qpng_create_info_struct png_create_info_struct
+#define qpng_read_info png_read_info
+#define qpng_set_compression_level png_set_compression_level
+#define qpng_set_filter png_set_filter
+#define qpng_set_expand png_set_expand
+#define qpng_set_palette_to_rgb png_set_palette_to_rgb
+#define qpng_set_tRNS_to_alpha png_set_tRNS_to_alpha
+#define qpng_set_gray_to_rgb png_set_gray_to_rgb
+#define qpng_set_filler png_set_filler
+#define qpng_set_IHDR png_set_IHDR
+#define qpng_set_packing png_set_packing
+#define qpng_set_bgr png_set_bgr
+#define qpng_set_interlace_handling png_set_interlace_handling
+#define qpng_read_update_info png_read_update_info
+#define qpng_read_image png_read_image
+#define qpng_read_end png_read_end
+#define qpng_destroy_read_struct png_destroy_read_struct
+#define qpng_destroy_write_struct png_destroy_write_struct
+#define qpng_set_read_fn png_set_read_fn
+#define qpng_set_write_fn png_set_write_fn
+#define qpng_get_valid png_get_valid
+#define qpng_get_rowbytes png_get_rowbytes
+#define qpng_get_channels png_get_channels
+#define qpng_get_bit_depth png_get_bit_depth
+#define qpng_get_IHDR png_get_IHDR
+#define qpng_access_version_number png_access_version_number
+#define qpng_write_info png_write_info
+#define qpng_write_row png_write_row
+#define qpng_write_end png_write_end
+
+#else
+/*
+ * Without LINK_TO_PNG, DarkPlaces assumes libpng 1.2 (in which png_uint_32
+ * is always unsigned long even if that's 64-bit), and then attempts
+ * to correct for it if it's actually 1.4 or 1.5 (where png_uint_32 is
+ * unsigned int if that's at least 32 bits, or unsigned long otherwise).
+ *
+ * With LINK_TO_PNG we use the library API/ABI as intended.
+ */
+typedef unsigned long png_uint_32;
 
 typedef struct png_struct_def *png_structp;
 typedef struct png_struct_def **png_structpp;
@@ -49,7 +119,7 @@ static void				(*qpng_set_palette_to_rgb)	(void*);
 static void				(*qpng_set_tRNS_to_alpha)	(void*);
 static void				(*qpng_set_gray_to_rgb)		(void*);
 static void				(*qpng_set_filler)			(void*, unsigned int, int);
-static void				(*qpng_set_IHDR)			(void*, void*, unsigned long, unsigned long, int, int, int, int, int);
+static void				(*qpng_set_IHDR)			(void*, void*, png_uint_32, png_uint_32, int, int, int, int, int);
 static void				(*qpng_set_packing)			(void*);
 static void				(*qpng_set_bgr)				(void*);
 static int				(*qpng_set_interlace_handling)	(void*);
@@ -64,7 +134,7 @@ static unsigned int		(*qpng_get_valid)			(void*, void*, unsigned int);
 static unsigned int		(*qpng_get_rowbytes)		(void*, void*);
 static unsigned char	(*qpng_get_channels)		(void*, void*);
 static unsigned char	(*qpng_get_bit_depth)		(void*, void*);
-static unsigned int		(*qpng_get_IHDR)			(void*, void*, unsigned long*, unsigned long*, int *, int *, int *, int *, int *);
+static png_uint_32		(*qpng_get_IHDR)			(void*, void*, png_uint_32 *, png_uint_32 *, int *, int *, int *, int *, int *);
 static unsigned int			(*qpng_access_version_number)		(void); // FIXME is this return type right? It is a png_uint_32 in libpng
 static void				(*qpng_write_info)			(void*, void*);
 static void				(*qpng_write_row)			(void*, unsigned char*);
@@ -82,6 +152,8 @@ static jmp_buf* (*qpng_set_longjmp_fn) (void *, qpng_longjmp_ptr, size_t);
 #define qpng_jmpbuf(png_ptr) \
 	(qpng_set_longjmp_fn ? qpng_jmpbuf_14(png_ptr) : qpng_jmpbuf_12(png_ptr))
 
+#define qpng_setjmp(png_ptr) setjmp(qpng_jmpbuf(png_ptr))
+
 static dllfunction_t pngfuncs[] =
 {
 	{"png_set_sig_bytes",		(void **) &qpng_set_sig_bytes},
@@ -129,6 +201,7 @@ static dllfunction_t png14funcs[] =
 dllhandle_t png_dll = NULL;
 dllhandle_t png14_dll = NULL;
 
+#endif
 
 /*
 =================================================================
@@ -147,6 +220,9 @@ Try to load the PNG DLL
 */
 qboolean PNG_OpenLibrary (void)
 {
+#ifdef LINK_TO_PNG
+	return TRUE;
+#else
 	const char* dllnames [] =
 	{
 #if WIN32
@@ -186,6 +262,7 @@ qboolean PNG_OpenLibrary (void)
 			return false;
 		}
 	return true;
+#endif
 }
 
 
@@ -198,8 +275,10 @@ Unload the PNG DLL
 */
 void PNG_CloseLibrary (void)
 {
+#ifndef LINK_TO_PNG
 	Sys_UnloadLibrary (&png14_dll);
 	Sys_UnloadLibrary (&png_dll);
+#endif
 }
 
 /*
@@ -210,6 +289,8 @@ void PNG_CloseLibrary (void)
 =================================================================
 */
 
+#ifndef LINK_TO_PNG
+
 #define PNG_LIBPNG_VER_STRING_12 "1.2.4"
 #define PNG_LIBPNG_VER_STRING_14 "1.4.0"
 #define PNG_LIBPNG_VER_STRING_15 "1.5.0"
@@ -230,6 +311,8 @@ void PNG_CloseLibrary (void)
 
 #define PNG_INFO_tRNS 0x0010
 
+#endif
+
 // this struct is only used for status information during loading
 static struct
 {
@@ -249,8 +332,8 @@ static struct
 	int		BitDepth;
 	int		BytesPerPixel;
 	int		ColorType;
-	unsigned long	Height; // retarded libpng 1.2 pngconf.h uses long (64bit/32bit depending on arch)
-	unsigned long	Width; // retarded libpng 1.2 pngconf.h uses long (64bit/32bit depending on arch)
+	png_uint_32	Height;
+	png_uint_32	Width;
 	int		Interlace;
 	int		Compression;
 	int		Filter;
@@ -307,18 +390,25 @@ unsigned char *PNG_LoadImage_BGRA (const unsigned char *raw, int filesize, int *
 
 	// FIXME: register an error handler so that abort() won't be called on error
 
+#ifndef LINK_TO_PNG
 	// No DLL = no PNGs
 	if (!png_dll)
 		return NULL;
+#endif
 
 	// png_sig_cmp is not fully const-correct
 	if(qpng_sig_cmp((unsigned char *) raw, 0, filesize))
 		return NULL;
+
 	png = (void *)qpng_create_read_struct(
+#ifdef LINK_TO_PNG
+		PNG_LIBPNG_VER_STRING,
+#else
 		(qpng_access_version_number() / 100 == 102) ? PNG_LIBPNG_VER_STRING_12 :
 		(qpng_access_version_number() / 100 == 104) ? PNG_LIBPNG_VER_STRING_14 :
 		(qpng_access_version_number() / 100 == 105) ? PNG_LIBPNG_VER_STRING_15 :
 		PNG_LIBPNG_VER_STRING_16, // nasty hack... whatever
+#endif
 		0, PNG_error_fn, PNG_warning_fn
 	);
 	if(!png)
@@ -330,7 +420,7 @@ unsigned char *PNG_LoadImage_BGRA (const unsigned char *raw, int filesize, int *
 
 	// NOTE: this relies on jmp_buf being the first thing in the png structure
 	// created by libpng! (this is correct for libpng 1.2.x)
-	if (setjmp(qpng_jmpbuf(png)))
+	if (qpng_setjmp(png))
 	{
 		if (my_png.Data)
 			Mem_Free(my_png.Data);
@@ -366,11 +456,16 @@ unsigned char *PNG_LoadImage_BGRA (const unsigned char *raw, int filesize, int *
 	qpng_read_info(png, pnginfo);
 	qpng_get_IHDR(png, pnginfo, &my_png.Width, &my_png.Height,&my_png.BitDepth, &my_png.ColorType, &my_png.Interlace, &my_png.Compression, &my_png.Filter);
 
+#ifndef LINK_TO_PNG
 	// this check guards against pngconf.h with unsigned int *width/height parameters on big endian systems by detecting the strange values and shifting them down 32bits
 	// (if it's little endian the unwritten bytes are the most significant
 	//  ones and we don't worry about that)
 	//
 	// this is only necessary because of retarded 64bit png_uint_32 types in libpng 1.2, which can (conceivably) vary by platform
+	//
+	// If LINK_TO_PNG is defined, we should never need this,
+	// because we get the correct definition of png_uint_32 from the
+	// system libpng header.
 #if LONG_MAX > 4000000000
 	if (my_png.Width > LONG_MAX || my_png.Height > LONG_MAX)
 	{
@@ -378,6 +473,7 @@ unsigned char *PNG_LoadImage_BGRA (const unsigned char *raw, int filesize, int *
 		my_png.Height >>= 32;
 	}
 #endif
+#endif
 
 	if (my_png.ColorType == PNG_COLOR_TYPE_PALETTE)
 		qpng_set_palette_to_rgb(png);
@@ -490,18 +586,24 @@ qboolean PNG_SaveImage_preflipped (const char *filename, int width, int height,
 	unsigned char ioBuffer[8192];
 	int passes, i, j;
 
+#ifndef LINK_TO_PNG
 	// No DLL = no JPEGs
 	if (!png_dll)
 	{
 		Con_Print("You need the libpng library to save PNG images\n");
 		return false;
 	}
+#endif
 
 	png = qpng_create_write_struct(
+#ifdef LINK_TO_PNG
+		PNG_LIBPNG_VER_STRING,
+#else
 		(qpng_access_version_number() / 100 == 102) ? PNG_LIBPNG_VER_STRING_12 :
 		(qpng_access_version_number() / 100 == 104) ? PNG_LIBPNG_VER_STRING_14 :
 		(qpng_access_version_number() / 100 == 105) ? PNG_LIBPNG_VER_STRING_15 :
 		PNG_LIBPNG_VER_STRING_16, // nasty hack... whatever
+#endif
 		0, PNG_error_fn, PNG_warning_fn
 	);
 	if(!png)
diff --git a/makefile b/makefile
index 6a00037..a46097f 100644
--- a/makefile
+++ b/makefile
@@ -114,6 +114,7 @@ ifeq ($(DP_MAKE_TARGET), linux)
 	DP_LINK_CRYPTO_RIJNDAEL?=dlopen
 	DP_LINK_VORBIS?=dlopen
 	DP_LINK_THEORA?=dlopen
+	DP_LINK_PNG?=dlopen
 endif
 
 # Mac OS X configuration
@@ -151,6 +152,7 @@ ifeq ($(DP_MAKE_TARGET), macosx)
 	DP_LINK_CRYPTO_RIJNDAEL?=dlopen
 	DP_LINK_VORBIS?=dlopen
 	DP_LINK_THEORA?=dlopen
+	DP_LINK_PNG?=dlopen
 
 	# on OS X, we don't build the CL by default because it uses deprecated
 	# and not-implemented-in-64bit Carbon
@@ -194,6 +196,7 @@ ifeq ($(DP_MAKE_TARGET), sunos)
 	DP_LINK_CRYPTO_RIJNDAEL?=dlopen
 	DP_LINK_VORBIS?=dlopen
 	DP_LINK_THEORA?=dlopen
+	DP_LINK_PNG?=dlopen
 endif
 
 # BSD configuration
@@ -231,6 +234,7 @@ endif
 	DP_LINK_CRYPTO_RIJNDAEL?=dlopen
 	DP_LINK_VORBIS?=dlopen
 	DP_LINK_THEORA?=dlopen
+	DP_LINK_PNG?=dlopen
 endif
 
 # Win32 configuration
@@ -292,6 +296,7 @@ ifeq ($(DP_MAKE_TARGET), mingw)
 	DP_LINK_CRYPTO_RIJNDAEL?=dlopen
 	DP_LINK_VORBIS?=dlopen
 	DP_LINK_THEORA?=dlopen
+	DP_LINK_PNG?=dlopen
 endif
 
 # set these to "" if you want to use dynamic loading instead
@@ -364,6 +369,16 @@ ifeq ($(DP_LINK_THEORA), dlopen)
 	LIB_THEORA=
 endif
 
+# png
+ifeq ($(DP_LINK_PNG), shared)
+	CFLAGS_LIBPNG=-DLINK_TO_PNG `pkg-config --cflags libpng`
+	LIB_PNG=`pkg-config --libs libpng`
+endif
+ifeq ($(DP_LINK_PNG), dlopen)
+	CFLAGS_LIBPNG=
+	LIB_PNG=
+endif
+
 ##### Sound configuration #####
 
 ifndef DP_SOUND_API
diff --git a/makefile.inc b/makefile.inc
index 9d29592..cb40f5a 100644
--- a/makefile.inc
+++ b/makefile.inc
@@ -172,7 +172,7 @@ OBJ_SDL= builddate.c sys_sdl.o vid_sdl.o thread_sdl.o $(OBJ_MENU) $(OBJ_SND_COMM
 
 
 # Compilation
-CFLAGS_COMMON=$(CFLAGS_MAKEDEP) $(CFLAGS_PRELOAD) $(CFLAGS_FS) $(CFLAGS_WARNINGS) $(CFLAGS_LIBZ) $(CFLAGS_LIBJPEG) $(CFLAGS_LIBVORBIS) $(CFLAGS_LIBTHEORA) $(CFLAGS_D3D) -D_FILE_OFFSET_BITS=64 -D__KERNEL_STRICT_NAMES -I../../../
+CFLAGS_COMMON=$(CFLAGS_MAKEDEP) $(CFLAGS_PRELOAD) $(CFLAGS_FS) $(CFLAGS_WARNINGS) $(CFLAGS_LIBZ) $(CFLAGS_LIBJPEG) $(CFLAGS_LIBVORBIS) $(CFLAGS_LIBTHEORA) $(CFLAGS_LIBPNG) $(CFLAGS_D3D) -D_FILE_OFFSET_BITS=64 -D__KERNEL_STRICT_NAMES -I../../../
 CFLAGS_CLIENT=-DCONFIG_MENU -DCONFIG_CD $(CFLAGS_VIDEO_CAPTURE)
 CFLAGS_SERVER=
 CFLAGS_DEBUG=-ggdb
@@ -205,7 +205,7 @@ LDFLAGS_RELEASE=$(OPTIM_RELEASE) -DSVNREVISION=`{ test -d .svn && svnversion; }
 
 OBJ_GLX= builddate.c sys_linux.o vid_glx.o thread_pthread.o keysym2ucs.o $(OBJ_MENU) $(OBJ_SOUND) $(OBJ_CD) $(OBJ_VIDEO_CAPTURE) $(OBJ_COMMON)
 
-LDFLAGS_UNIXCOMMON=-lm $(LIB_ODE) $(LIB_Z) $(LIB_JPEG) $(LIB_CRYPTO) $(LIB_CRYPTO_RIJNDAEL)
+LDFLAGS_UNIXCOMMON=-lm $(LIB_ODE) $(LIB_Z) $(LIB_JPEG) $(LIB_CRYPTO) $(LIB_CRYPTO_RIJNDAEL) $(LIB_PNG)
 LDFLAGS_UNIXCL=-L$(UNIX_X11LIBPATH) -lX11 -lXpm -lXext -lXxf86vm -pthread $(LIB_SOUND) $(LIB_VORBIS) $(LIB_THEORA)
 LDFLAGS_UNIXCL_PRELOAD=-lz -ljpeg -lpng -logg -ltheora -lvorbis -lvorbisenc -lvorbisfile -lcurl
 LDFLAGS_UNIXSV_PRELOAD=-lz -ljpeg -lpng -lcurl