[libpng16] Worked around a false-positive Coverity issue in pngvalid.c.

ANNOUNCE

-Libpng 1.6.21rc02 - January 7, 2016
+Libpng 1.6.21rc03 - January 13, 2016
 
 This is not intended to be a public release.  It will be replaced
 within a few weeks by a public version or by another test version.
@@ -8,20 +8,20 @@ Files available for download:
 Source files with LF line endings (for Unix/Linux) and with a
 "configure" script
 
-   1.6.21rc02.tar.xz (LZMA-compressed, recommended)
-   1.6.21rc02.tar.gz
+   1.6.21rc03.tar.xz (LZMA-compressed, recommended)
+   1.6.21rc03.tar.gz
 
 Source files with CRLF line endings (for Windows), without the
 "configure" script
 
-   /scratch/glennrp/Libpng16/lp1621r02.7z  (LZMA-compressed, recommended)
-   /scratch/glennrp/Libpng16/lp1621r02.zip
+   /scratch/glennrp/Libpng16/lp1621r03.7z  (LZMA-compressed, recommended)
+   /scratch/glennrp/Libpng16/lp1621r03.zip
 
 Other information:
 
-   1.6.21rc02-README.txt
-   1.6.21rc02-LICENSE.txt
-   libpng-1.6.21rc02-*.asc (armored detached GPG signatures)
+   1.6.21rc03-README.txt
+   1.6.21rc03-LICENSE.txt
+   libpng-1.6.21rc03-*.asc (armored detached GPG signatures)
 
 Changes since the last public release (1.6.20):
 
@@ -60,6 +60,9 @@ Version 1.6.21rc02 [January 7, 2016]
   Marked 'limit' UNUSED in transform_range_check().  This only affects
     release builds.
 
+Version 1.6.21rc03 [January 13, 2016]
+  Worked around a false-positive Coverity issue in pngvalid.c.
+
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
 https://lists.sourceforge.net/lists/listinfo/png-mng-implement

CHANGES

@@ -5481,6 +5481,9 @@ Version 1.6.21rc02 [January 7, 2016]
   Marked 'limit' UNUSED in transform_range_check().  This only affects
     release builds.
 
+Version 1.6.21rc03 [January 13, 2016]
+  Worked around a false-positive Coverity issue in pngvalid.c.
+
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
 https://lists.sourceforge.net/lists/listinfo/png-mng-implement

contrib/libtests/pngvalid.c

@@ -309,8 +309,13 @@ static void r16(png_uint_16p p16, size_t count)
    }
 }
 
-#define R16(this)\
+#ifdef __COVERITY__
+#  define R16(this)\
+   r16(&(this), (sizeof (this))/2U/*(sizeof (png_uint_16))*/)
+#else
+#  define R16(this)\
    r16(&(this), (sizeof (this))/(sizeof (png_uint_16)))
+#endif
 
 #if defined PNG_READ_RGB_TO_GRAY_SUPPORTED ||\
     defined PNG_READ_FILLER_SUPPORTED
@@ -326,8 +331,14 @@ static void r32(png_uint_32p p32, size_t count)
    }
 }
 
-#define R32(this)\
+#ifdef __COVERITY__
+#  define R32(this)\
+   r32(&(this), (sizeof (this))/4U/*(sizeof (png_uint_32))*/)
+#else
+#  define R32(this)\
    r32(&(this), (sizeof (this))/(sizeof (png_uint_32)))
+#endif
+
 #endif /* READ_FILLER || READ_RGB_TO_GRAY */
 
 #endif /* READ || WRITE_tRNS || WRITE_FILTER */