MINIFICPP-1383 fix negative numbers, constexpr

apache · Oct 1, 2020 · fcdecd3 · fcdecd3
1 parent c3205e7
commit fcdecd3
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Showing 2 changed files with 18 additions and 20 deletions.
diff --git a/libminifi/include/utils/GeneralUtils.h b/libminifi/include/utils/GeneralUtils.h
@@ -19,7 +19,6 @@
 #ifndef LIBMINIFI_INCLUDE_UTILS_GENERALUTILS_H_
 #define LIBMINIFI_INCLUDE_UTILS_GENERALUTILS_H_
 
-#include <cmath>
 #include <memory>
 #include <type_traits>
 #include <utility>
@@ -43,10 +42,11 @@ using std::make_unique;
 #endif /* < C++14 */
 
 template<typename T, typename = typename std::enable_if<std::is_integral<T>::value>::type>
-T intdiv_ceil(T numerator, T denominator) {
-  gsl_Expects(numerator >= 0 && denominator > 0);
+constexpr T intdiv_ceil(T numerator, T denominator) {
   // note: division and remainder is 1 instruction on x86
-  return numerator / denominator + (numerator % denominator > 0);
+  return gsl_Expects(denominator != 0), ((numerator >= 0) != (denominator > 0)
+      ? numerator / denominator  // negative result rounds towards zero, i.e. up
+      : numerator / denominator + (numerator % denominator != 0));
 }
 
 using gsl::owner;

diff --git a/libminifi/test/unit/GeneralUtilsTest.cpp b/libminifi/test/unit/GeneralUtilsTest.cpp
@@ -32,22 +32,20 @@ TEST_CASE("GeneralUtils::make_unique", "[make_unique]") {
   REQUIRE("test string" == *pstr);
 }
 
-TEST_CASE("GeneralUtils::intdiv_ceil", "[intdiv_ceil]") {
-  REQUIRE(0 == utils::intdiv_ceil(0, 1));
-  REQUIRE(0 == utils::intdiv_ceil(0, 2));
-  REQUIRE(1 == utils::intdiv_ceil(1, 2));
-  REQUIRE(1 == utils::intdiv_ceil(1, 3));
-  REQUIRE(1 == utils::intdiv_ceil(3, 3));
-  REQUIRE(2 == utils::intdiv_ceil(4, 3));
-  REQUIRE(2 == utils::intdiv_ceil(4, 3));
-  //REQUIRE(0 == utils::intdiv_ceil(-1, 3));
-  //REQUIRE(-1 == utils::intdiv_ceil(-3, 3));
-  //REQUIRE(-1 == utils::intdiv_ceil(-4, 3));
-  //REQUIRE(2 == utils::intdiv_ceil(-4, -3));
-  //REQUIRE(2 == utils::intdiv_ceil(-5, -3));
-  //REQUIRE(0 == utils::intdiv_ceil(1, -3));
-  //REQUIRE(-1 == utils::intdiv_ceil(5, -3));
-}
+static_assert(0 == utils::intdiv_ceil(0, 1), "");
+static_assert(0 == utils::intdiv_ceil(0, 2), "");
+static_assert(1 == utils::intdiv_ceil(1, 2), "");
+static_assert(1 == utils::intdiv_ceil(1, 3), "");
+static_assert(1 == utils::intdiv_ceil(3, 3), "");
+static_assert(2 == utils::intdiv_ceil(4, 3), "");
+static_assert(2 == utils::intdiv_ceil(4, 3), "");
+static_assert(0 == utils::intdiv_ceil(-1, 3), "");
+static_assert(-1 == utils::intdiv_ceil(-3, 3), "");
+static_assert(-1 == utils::intdiv_ceil(-4, 3), "");
+static_assert(2 == utils::intdiv_ceil(-4, -3), "");
+static_assert(2 == utils::intdiv_ceil(-5, -3), "");
+static_assert(0 == utils::intdiv_ceil(1, -3), "");
+static_assert(-1 == utils::intdiv_ceil(5, -3), "");
 
 TEST_CASE("GeneralUtils::exchange", "[exchange]") {
   int a = 1;