C++11 support for numeric_limits<Half>::max_digits10() and lowest()

AcademySoftwareFoundation · Aug 8, 2018 · 2d931ba · 2d931ba
1 parent 7fda69a
commit 2d931ba
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Showing 3 changed files with 25 additions and 1 deletion.
diff --git a/IlmBase/Half/half.h b/IlmBase/Half/half.h
@@ -277,6 +277,10 @@ HALF_EXPORT void        printBits   (char  c[35], float f);
 #define HALF_DIG	2		// Number of base 10 digits that
 					// can be represented without change
 
+#define HALF_DECIMAL_DIG	5	// Number of base-10 digits that are
+					// necessary to uniquely represent all
+					// distinct values
+
 #define HALF_RADIX	2		// Base of the exponent
 
 #define HALF_MIN_EXP	-13		// Minimum negative integer such that

diff --git a/IlmBase/Half/halfLimits.h b/IlmBase/Half/halfLimits.h
@@ -94,6 +94,15 @@ class numeric_limits <half>
     static const bool traps = true;
     static const bool tinyness_before = false;
     static const float_round_style round_style = round_to_nearest;
+
+#if __cplusplus >= 201103L
+
+    // C++11 additions.
+    static constexpr int max_digits10 = HALF_DECIMAL_DIG;
+    static half lowest () {return -HALF_MAX;}
+
+#endif
+
 };
 
 

diff --git a/IlmBase/HalfTest/testLimits.cpp b/IlmBase/HalfTest/testLimits.cpp
@@ -2,7 +2,7 @@
 #include "halfLimits.h"
 #include <iostream>
 #include <assert.h>
-
+#include <cmath>
 
 using namespace std;
 
@@ -89,6 +89,17 @@ testLimits()
 	assert (h.isInfinity());
     }
 
+#if __cplusplus >= 201103L
+
+    cout << "max_digits10\n";
+    assert (numeric_limits<half>::max_digits10
+            == std::ceil(numeric_limits<half>::digits * std::log10(2) + 1));
+
+    cout << "lowest\n";
+    assert (numeric_limits<half>::lowest() == -HALF_MAX);
+
+#endif
+
     cout << "ok\n\n" << flush;
 
 }