Merge pull request #154 from chfast/div_normalize

Introduce intx::internal namespace in preparation for header-only library
chfast · Jun 17, 2020 · cac1c96 · cac1c96
2 parents 8eaadda + d8210d3
commit cac1c96
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Showing 4 changed files with 20 additions and 16 deletions.
diff --git a/lib/intx/div.cpp b/lib/intx/div.cpp
@@ -7,7 +7,7 @@
 
 namespace intx
 {
-namespace
+namespace internal
 {
 /// Divides arbitrary long unsigned integer by 64-bit unsigned integer (1 word).
 /// @param u    The array of a normalized numerator words. It will contain
@@ -88,7 +88,8 @@ inline uint64_t submul(
     return borrow;
 }
 
-void udivrem_knuth(uint64_t q[], uint64_t u[], int ulen, const uint64_t d[], int dlen) noexcept
+inline void udivrem_knuth(
+    uint64_t q[], uint64_t u[], int ulen, const uint64_t d[], int dlen) noexcept
 {
     INTX_REQUIRE(dlen >= 3);
     INTX_REQUIRE(ulen >= dlen);
@@ -129,35 +130,35 @@ void udivrem_knuth(uint64_t q[], uint64_t u[], int ulen, const uint64_t d[], int
     }
 }
 
-}  // namespace
+}  // namespace internal
 
 template <unsigned N>
 div_result<uint<N>> udivrem(const uint<N>& u, const uint<N>& v) noexcept
 {
-    auto na = normalize(u, v);
+    auto na = internal::normalize(u, v);
 
     if (na.num_numerator_words <= na.num_divisor_words)
         return {0, u};
 
     if (na.num_divisor_words == 1)
     {
-        auto r =
-            udivrem_by1(as_words(na.numerator), na.num_numerator_words, as_words(na.divisor)[0]);
+        const auto r = internal::udivrem_by1(
+            as_words(na.numerator), na.num_numerator_words, as_words(na.divisor)[0]);
         return {na.numerator, r >> na.shift};
     }
 
     if (na.num_divisor_words == 2)
     {
-        auto d = as_words(na.divisor);
-        auto r = udivrem_by2(as_words(na.numerator), na.num_numerator_words, {d[1], d[0]});
+        const auto d = as_words(na.divisor);
+        const auto r =
+            internal::udivrem_by2(as_words(na.numerator), na.num_numerator_words, {d[1], d[0]});
         return {na.numerator, r >> na.shift};
     }
 
     auto un = as_words(na.numerator);  // Will be modified.
 
     uint<N> q;
-
-    udivrem_knuth(
+    internal::udivrem_knuth(
         as_words(q), &un[0], na.num_numerator_words, as_words(na.divisor), na.num_divisor_words);
 
     uint<N> r;

diff --git a/lib/intx/div.hpp b/lib/intx/div.hpp
@@ -8,6 +8,8 @@
 
 namespace intx
 {
+namespace internal
+{
 template <unsigned N>
 struct normalized_div_args
 {
@@ -67,4 +69,5 @@ template <typename IntT>
     return na;
 }
 
+}  // namespace internal
 }  // namespace intx
diff --git a/test/benchmarks/bench_div.cpp b/test/benchmarks/bench_div.cpp
@@ -27,7 +27,7 @@ inline uint64_t udiv_by_reciprocal(uint64_t uu, uint64_t du) noexcept
 }
 
 
-template <decltype(normalize<uint512>) NormalizeFn>
+template <decltype(internal::normalize<uint512>) NormalizeFn>
 static void div_normalize(benchmark::State& state)
 {
     auto u = uint512{{48882153453, 100324254353}, {4343242153453, 1324254353}};
@@ -40,7 +40,7 @@ static void div_normalize(benchmark::State& state)
         benchmark::DoNotOptimize(x);
     }
 }
-BENCHMARK_TEMPLATE(div_normalize, normalize);
+BENCHMARK_TEMPLATE(div_normalize, internal::normalize);
 
 constexpr uint64_t neg(uint64_t x) noexcept
 {

diff --git a/test/unittests/test_div.cpp b/test/unittests/test_div.cpp
@@ -13,7 +13,7 @@ TEST(div, normalize)
 {
     uint512 u;
     uint512 v = 1;
-    auto na = normalize(u, v);
+    auto na = internal::normalize(u, v);
     EXPECT_EQ(na.shift, 63u);
     EXPECT_EQ(na.num_divisor_words, 1);
     EXPECT_EQ(na.num_numerator_words, 0);
@@ -23,7 +23,7 @@ TEST(div, normalize)
 
     u = uint512{1414, 1313};
     v = uint512{12, 1212};
-    na = normalize(u, v);
+    na = internal::normalize(u, v);
     EXPECT_EQ(na.shift, 60u);
     EXPECT_EQ(na.num_divisor_words, 5);
     EXPECT_EQ(na.num_numerator_words, 6);
@@ -33,7 +33,7 @@ TEST(div, normalize)
 
     u = uint512{3} << 510;
     v = uint256{0xffffffffffffffff, 1};
-    na = normalize(u, v);
+    na = internal::normalize(u, v);
     EXPECT_EQ(na.shift, 0u);
     EXPECT_EQ(na.num_divisor_words, 3);
     EXPECT_EQ(na.num_numerator_words, 8);
@@ -43,7 +43,7 @@ TEST(div, normalize)
 
     u = uint512{7} << 509;
     v = uint256{0x3fffffffffffffff, 1};
-    na = normalize(u, v);
+    na = internal::normalize(u, v);
     EXPECT_EQ(na.shift, 2u);
     EXPECT_EQ(na.num_divisor_words, 3);
     EXPECT_EQ(na.num_numerator_words, 9);