[libpng16] Fixed array size calculations to avoid warnings. At various points

in the code the number of elements in an array is calculated using
sizeof.  This generates a compile time constant of type (size_t) which
is then typically assigned to an (unsigned int) or (int). Some versions
of GCC on 64-bit systems warn about the apparent narrowing, even though
the same compiler does apparently generate the correct, in-range,
numeric constant.  This adds appropriate, safe, casts to make the
warnings go away.
This commit is contained in:
John Bowler
2014-11-05 17:19:36 -06:00
committed by Glenn Randers-Pehrson
parent 6f2c50e7fc
commit 03df189954
5 changed files with 35 additions and 5 deletions

View File

@@ -157,6 +157,13 @@ define_exception_type(struct png_store*);
&(ps)->exception_context
#define context(ps,fault) anon_context(ps); png_store *fault
/* This macro returns the number of elements in an array as an (unsigned int),
* it is necessary to avoid the inability of certain versions of GCC to use
* the value of a compile-time constant when performing range checks. It must
* be passed an array name.
*/
#define ARRAY_SIZE(a) ((unsigned int)((sizeof (a))/(sizeof (a)[0])))
/******************************* UTILITIES ************************************/
/* Error handling is particularly problematic in production code - error
* handlers often themselves have bugs which lead to programs that detect
@@ -4106,7 +4113,7 @@ make_errors(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type,
standard_name(name, sizeof name, 0, colour_type, 1<<bdlo, 0,
interlace_type, 0, 0, 0);
for (test=0; test<(sizeof error_test)/(sizeof error_test[0]); ++test)
for (test=0; test<ARRAY_SIZE(error_test); ++test)
{
make_error(&pm->this, colour_type, DEPTH(bdlo), interlace_type,
test, name);
@@ -10098,12 +10105,12 @@ int main(int argc, char **argv)
/* Store the test gammas */
pm.gammas = gammas;
pm.ngammas = (sizeof gammas) / (sizeof gammas[0]);
pm.ngammas = ARRAY_SIZE(gammas);
pm.ngamma_tests = 0; /* default to off */
/* And the test encodings */
pm.encodings = test_encodings;
pm.nencodings = (sizeof test_encodings) / (sizeof test_encodings[0]);
pm.nencodings = ARRAY_SIZE(test_encodings);
pm.sbitlow = 8U; /* because libpng doesn't do sBIT below 8! */