If linking libpng normally, use its header to get the png_uint_32 type

This avoids needing to work around ABI differences, particularly in
newer versions of libpng: if we know which version we're using, it's
all simpler.

Origin: vendor, Debian

diff --git a/image_png.c b/image_png.c
index 5c9d0571ecb3bd39591f56d6d78fe77787db71f4..65047ef6790f329f0cb76a740264ff728b13950b 100644 (file)
--- a/image_png.c
+++ b/image_png.c
@@ -82,6 +82,16 @@ my_setjmp (jmp_buf env)
 
 #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 void *png_structp;
 typedef void **png_structpp;
 typedef void *png_infop;
@@ -100,7 +110,7 @@ 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*);
@@ -115,7 +125,7 @@ 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*);
@@ -300,8 +310,8 @@ 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;
@@ -419,17 +429,23 @@ 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)
        {
                my_png.Width >>= 32;
                my_png.Height >>= 32;
        }
+#endif
 #endif
 
        if (my_png.ColorType == PNG_COLOR_TYPE_PALETTE)