[libpng16] Quieted Coverity issues in pngfix.c, png-fix-itxt.c, pngvalid.c,

pngstest.c, and pngimage.c. Most seem harmless, but png-fix-itxt
would only work with iTXt chunks with length 255 or less.

Fixed cexcept.h in which GCC 5 reported that one of the auto
variables in the Try macro needs to be volatile to prevent value
being lost over the setjmp, and fixed g++ build breaks (John Bowler).

ANNOUNCE

@@ -1,5 +1,5 @@
 
-Libpng 1.7.0beta63 - June 3, 2015
+Libpng 1.7.0beta63 - June 4, 2015
 
 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.
@@ -814,10 +814,13 @@ Version 1.7.0beta62 [June 1, 2015]
     far as we can tell, no one uses it. The png_set_filter_heuristics() and
     png_set_filter_heuristics_fixed() APIs are retained but deprecated.
 
-Version 1.7.0beta63 [June 3, 2015]
+Version 1.7.0beta63 [June 4, 2015]
   Quieted Coverity issues in pngfix.c, png-fix-itxt.c, pngvalid.c,
     pngstest.c, and pngimage.c. Most seem harmless, but png-fix-itxt
     would only work with iTXt chunks with length 255 or less.
+  Fixed cexcept.h in which GCC 5 reported that one of the auto
+    variables in the Try macro needs to be volatile to prevent value
+    being lost over the setjmp, and fixed g++ build breaks (John Bowler).
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit

CHANGES

@@ -5109,10 +5109,13 @@ Version 1.7.0beta62 [June 1, 2015]
     far as we can tell, no one uses it. The png_set_filter_heuristics() and
     png_set_filter_heuristics_fixed() APIs are retained but deprecated.
 
-Version 1.7.0beta63 [June 3, 2015]
+Version 1.7.0beta63 [June 4, 2015]
   Quieted Coverity issues in pngfix.c, png-fix-itxt.c, pngvalid.c,
     pngstest.c, and pngimage.c. Most seem harmless, but png-fix-itxt
     would only work with iTXt chunks with length 255 or less.
+  Fixed cexcept.h in which GCC 5 reported that one of the auto
+    variables in the Try macro needs to be volatile to prevent value
+    being lost over the setjmp, and fixed g++ build breaks (John Bowler).
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit

contrib/libtests/pngvalid.c

@@ -4100,7 +4100,7 @@ make_error(png_store* volatile psIn, png_byte PNG_CONST colour_type,
 
    Try
    {
-      png_structp pp;
+      volatile png_structp pp;
       png_infop pi;
 
       pp = set_store_for_write(ps, &pi, name);

contrib/tools/png-fix-itxt.c

@@ -57,10 +57,10 @@ for (;;)
  {
    /* Read the length */
    unsigned long length; /* must be 32 bits! */
-   c=GETBREAK; buf[0] = c; length  = (c % 0xff); length <<= 8;
-   c=GETBREAK; buf[1] = c; length += (c % 0xff); length <<= 8;
-   c=GETBREAK; buf[2] = c; length += (c % 0xff); length <<= 8;
-   c=GETBREAK; buf[3] = c; length += (c % 0xff);
+   c=GETBREAK; buf[0] = c; length  = (c & 0xff); length <<= 8;
+   c=GETBREAK; buf[1] = c; length += (c & 0xff); length <<= 8;
+   c=GETBREAK; buf[2] = c; length += (c & 0xff); length <<= 8;
+   c=GETBREAK; buf[3] = c; length += (c & 0xff);
 
    /* Read the chunkname */
    c=GETBREAK; buf[4] = c;

contrib/visupng/cexcept.h

@@ -1,11 +1,12 @@
 /*===
-cexcept.h 2.0.1 (2008-Jul-19-Sat)
+cexcept.h 2.0.1 (2008-Jul-19-Sat, modified 2015-Jun-03-Mon)
 http://www.nicemice.net/cexcept/
 Adam M. Costello
 http://www.nicemice.net/amc/
 
 An interface for exception-handling in ANSI C (C89 and subsequent ISO
-standards), developed jointly with Cosmin Truta.
+standards), developed jointly with Cosmin Truta.  Revised by John Bowler,
+June 2015, to declare exception_env and exception_prev "volatile".
 
     Copyright (c) 2000-2008 Adam M. Costello and Cosmin Truta.
     This software may be modified only if its author and version
@@ -210,7 +211,7 @@ struct exception_context { \
 
 #define Try \
   { \
-    jmp_buf *exception__prev, exception__env; \
+    jmp_buf * volatile exception__prev, exception__env; \
     exception__prev = the_exception_context->penv; \
     the_exception_context->penv = &exception__env; \
     if (setjmp(exception__env) == 0) { \

png.c

@@ -689,13 +689,13 @@ png_get_copyright(png_const_structrp png_ptr)
 #else
 #  ifdef __STDC__
    return PNG_STRING_NEWLINE \
-     "libpng version 1.7.0beta63 - June 1, 2015" PNG_STRING_NEWLINE \
+     "libpng version 1.7.0beta63 - June 4, 2015" PNG_STRING_NEWLINE \
      "Copyright (c) 1998-2015 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \
      "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
      "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
      PNG_STRING_NEWLINE;
 #  else
-      return "libpng version 1.7.0beta63 - June 1, 2015\
+      return "libpng version 1.7.0beta63 - June 4, 2015\
       Copyright (c) 1998-2015 Glenn Randers-Pehrson\
       Copyright (c) 1996-1997 Andreas Dilger\
       Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
@@ -2795,7 +2795,7 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
           */
 
          {
-            int czero, clead, cdigits;
+            unsigned int czero, clead, cdigits;
             char exponent[10];
 
             /* Allow up to two leading zeros - this will not lengthen
@@ -2825,7 +2825,7 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
                 * of the loop don't break the number into parts so
                 * that the final digit is rounded.
                 */
-               if (cdigits+czero-clead+1 < (int)precision)
+               if (cdigits+czero+1 < precision+clead)
                   fp = modf(fp, &d);
 
                else
@@ -2931,7 +2931,7 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
                   *ascii++ = png_check_char(png_ptr, 48 + (int)d), ++cdigits;
                }
             }
-            while (cdigits+czero-clead < (int)precision && fp > DBL_MIN);
+            while (cdigits+czero < precision+clead && fp > DBL_MIN);
 
             /* The total output count (max) is now 4+precision */
 
@@ -2999,7 +2999,7 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
             /* Need another size check here for the exponent digits, so
              * this need not be considered above.
              */
-            if ((int)size > cdigits)
+            if (size > cdigits)
             {
                while (cdigits > 0) *ascii++ = exponent[--cdigits];
 

pngwutil.c

@@ -2195,7 +2195,7 @@ png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
          {
             png_bytep sp;
             png_bytep dp;
-            int shift;
+            unsigned int shift;
             int d;
             int value;
             png_uint_32 i;
@@ -2233,7 +2233,7 @@ png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
          {
             png_bytep sp;
             png_bytep dp;
-            int shift;
+            unsigned int shift;
             int d;
             int value;
             png_uint_32 i;
@@ -2270,7 +2270,7 @@ png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
          {
             png_bytep sp;
             png_bytep dp;
-            int shift;
+            unsigned int shift;
             int d;
             int value;
             png_uint_32 i;