div: Make udivrem() a proper template

chfast · Jun 13, 2019 · 9386419 · 9386419
1 parent 232b2c1
commit 9386419
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Showing 3 changed files with 10 additions and 24 deletions.
diff --git a/include/intx/int128.hpp b/include/intx/int128.hpp
@@ -771,7 +771,7 @@ inline std::string to_string(uint<N> x, int base = 10)
     while (x != 0)
     {
         // TODO: Use constexpr udivrem_1?
-        const auto res = udivrem(x, base);
+        const auto res = udivrem(x, uint<N>{base});
         const auto d = int(res.rem);
         const auto c = d < 10 ? '0' + d : 'a' + d - 10;
         s.push_back(char(c));

diff --git a/include/intx/intx.hpp b/include/intx/intx.hpp
@@ -730,8 +730,8 @@ inline typename std::enable_if<sizeof(Word) < sizeof(Int), unsigned>::type count
     return h != 0 ? h + (num_words / 2) : l;
 }
 
-div_result<uint256> udivrem(const uint256& u, const uint256& v) noexcept;
-div_result<uint512> udivrem(const uint512& x, const uint512& y) noexcept;
+template <unsigned N>
+div_result<uint<N>> udivrem(const uint<N>& u, const uint<N>& v) noexcept;
 
 template <unsigned N>
 constexpr div_result<uint<N>> sdivrem(const uint<N>& u, const uint<N>& v) noexcept

diff --git a/lib/intx/div.cpp b/lib/intx/div.cpp
@@ -8,18 +8,6 @@ namespace intx
 {
 namespace
 {
-union uint512_words64
-{
-    using word_type = uint64_t;
-
-    const uint512 number;
-    word_type words[uint512::num_words];
-
-    constexpr explicit uint512_words64(uint512 x = {}) noexcept : number{x} {}
-
-    word_type& operator[](size_t index) { return words[index]; }
-};
-
 /// Divides arbitrary long unsigned integer by 64-bit unsigned integer (1 word).
 /// @param u  The array of a normalized numerator words. It will contain the quotient after
 ///           execution.
@@ -151,13 +139,8 @@ void udivrem_knuth(uint64_t q[], uint64_t un[], int m, const uint64_t vn[], int
 
 }  // namespace
 
-div_result<uint256> udivrem(const uint256& u, const uint256& v) noexcept
-{
-    auto x = udivrem(uint512{u}, uint512{v});
-    return {x.quot.lo, x.rem.lo};
-}
-
-div_result<uint512> udivrem(const uint512& u, const uint512& v) noexcept
+template <unsigned N>
+div_result<uint<N>> udivrem(const uint<N>& u, const uint<N>& v) noexcept
 {
     auto na = normalize(u, v);
 
@@ -183,8 +166,8 @@ div_result<uint512> udivrem(const uint512& u, const uint512& v) noexcept
 
     auto un = as_words(na.numerator);  // Will be modified.
 
-    uint512 q;
-    uint512 r;
+    uint<N> q;
+    uint<N> r;
     auto rw = as_words(r);
 
     udivrem_knuth(as_words(q), &un[0], m, as_words(na.denominator), n);
@@ -195,4 +178,7 @@ div_result<uint512> udivrem(const uint512& u, const uint512& v) noexcept
     return {q, r};
 }
 
+template div_result<uint256> udivrem(const uint256& u, const uint256& v) noexcept;
+template div_result<uint512> udivrem(const uint512& u, const uint512& v) noexcept;
+
 }  // namespace intx