[types] Apply Safe::abs() in floatToRationalCast & gcd

Also check for infinity in floatToRationalCast as depending on the
compiler special values of floats are converted to either
LONGMAX/LONGMIN or +/-inf

include/exiv2/types.hpp

@@ -38,6 +38,7 @@
 #include <string>
 #include <vector>
 #include <iosfwd>
+#include <limits>
 #include <utility>
 #include <algorithm>
 #include <sstream>
@@ -555,8 +556,13 @@ namespace Exiv2 {
 #ifdef _MSC_VER
 #pragma warning( disable : 4146 )
 #endif
-        if (n < zero)
-            n = -n;
+        if (n < zero) {
+            if (n == std::numeric_limits<IntType>::min()) {
+                n = std::numeric_limits<IntType>::max();
+            } else {
+                n = -n;
+            }
+        }
         if (m < zero)
             m = -m;
 #ifdef _MSC_VER

src/types.cpp

@@ -29,6 +29,7 @@
 #include "types.hpp"
 #include "i18n.h"                               // for _exvGettext
 #include "unused.h"
+#include "safe_op.hpp"
 
 // + standard includes
 #ifdef EXV_UNICODE_PATH
@@ -46,6 +47,7 @@
 #include <cassert>
 #include <cstring>
 #include <cmath>
+#include <math.h>
 
 // *****************************************************************************
 namespace {
@@ -657,11 +659,15 @@ namespace Exiv2 {
 
     Rational floatToRationalCast(float f)
     {
+        if (isinf(f)) {
+            return Rational(f > 0 ? 1 : -1, 0);
+        }
         // Beware: primitive conversion algorithm
         int32_t den = 1000000;
-        if (std::labs(static_cast<long>(f)) > 2147) den = 10000;
-        if (std::labs(static_cast<long>(f)) > 214748) den = 100;
-        if (std::labs(static_cast<long>(f)) > 21474836) den = 1;
+        const long f_as_long = static_cast<long>(f);
+        if (Safe::abs(f_as_long) > 2147) den = 10000;
+        if (Safe::abs(f_as_long) > 214748) den = 100;
+        if (Safe::abs(f_as_long) > 21474836) den = 1;
         const float rnd = f >= 0 ? 0.5f : -0.5f;
         const int32_t nom = static_cast<int32_t>(f * den + rnd);
         const int32_t g = gcd(nom, den);