Merge pull request #1386 from boostorg/1383

Fix the `quantize()` function

Author: mborland

include/boost/decimal/cmath.hpp

@@ -201,6 +201,11 @@ BOOST_DECIMAL_EXPORT constexpr auto samequantum(decimal64_t lhs, decimal64_t rhs
     return samequantumd64(lhs, rhs);
 }
 
+BOOST_DECIMAL_EXPORT constexpr auto samequantum(decimal_fast64_t lhs, decimal_fast64_t rhs) noexcept -> bool
+{
+    return samequantumd64f(lhs, rhs);
+}
+
 BOOST_DECIMAL_EXPORT constexpr auto samequantum(decimal128_t lhs, decimal128_t rhs) noexcept -> bool
 {
     return samequantumd128(lhs, rhs);
@@ -241,31 +246,6 @@ BOOST_DECIMAL_EXPORT constexpr auto quantexp(decimal_fast128_t x) noexcept -> in
     return quantexpd128f(x);
 }
 
-BOOST_DECIMAL_EXPORT constexpr auto quantize(decimal32_t lhs, decimal32_t rhs) noexcept -> decimal32_t
-{
-    return quantized32(lhs, rhs);
-}
-
-BOOST_DECIMAL_EXPORT constexpr auto quantize(decimal_fast32_t lhs, decimal_fast32_t rhs) noexcept -> decimal_fast32_t
-{
-    return quantized32f(lhs, rhs);
-}
-
-BOOST_DECIMAL_EXPORT constexpr auto quantize(decimal64_t lhs, decimal64_t rhs) noexcept -> decimal64_t
-{
-    return quantized64(lhs, rhs);
-}
-
-BOOST_DECIMAL_EXPORT constexpr auto quantize(decimal128_t lhs, decimal128_t rhs) noexcept -> decimal128_t
-{
-    return quantized128(lhs, rhs);
-}
-
-BOOST_DECIMAL_EXPORT constexpr auto quantize(decimal_fast128_t lhs, decimal_fast128_t rhs) noexcept -> decimal_fast128_t
-{
-    return quantized128f(lhs, rhs);
-}
-
 } // namespace decimal
 } // namespace boost
 

include/boost/decimal/decimal128_t.hpp

@@ -26,6 +26,7 @@
 #include <boost/decimal/detail/to_decimal.hpp>
 #include <boost/decimal/detail/promotion.hpp>
 #include <boost/decimal/detail/check_non_finite.hpp>
+#include <boost/decimal/detail/quantize_impl.hpp>
 #include <boost/decimal/detail/shrink_significand.hpp>
 #include <boost/decimal/detail/cmath/isfinite.hpp>
 #include <boost/decimal/detail/cmath/fpclassify.hpp>
@@ -556,7 +557,8 @@ BOOST_DECIMAL_EXPORT class decimal128_t final
     friend BOOST_DECIMAL_CUDA_CONSTEXPR auto quantexpd128(decimal128_t x) noexcept -> int;
 
     // 3.6.6 Quantize
-    friend BOOST_DECIMAL_CUDA_CONSTEXPR auto quantized128(const decimal128_t& lhs, const decimal128_t& rhs) noexcept -> decimal128_t;
+    template <BOOST_DECIMAL_DECIMAL_FLOATING_TYPE T>
+    friend BOOST_DECIMAL_CUDA_CONSTEXPR auto quantize(T lhs, T rhs) noexcept -> T;
 
     // <cmath> functions that need to be friends
     template <BOOST_DECIMAL_DECIMAL_FLOATING_TYPE T>
@@ -2161,44 +2163,6 @@ BOOST_DECIMAL_CUDA_CONSTEXPR auto quantexpd128(const decimal128_t x) noexcept ->
     return static_cast<int>(x.unbiased_exponent());
 }
 
-// 3.6.6
-// Returns: a number that is equal in value (except for any rounding) and sign to x,
-// and which has an exponent set to be equal to the exponent of y.
-// If the exponent is being increased, the value is correctly rounded according to the current rounding mode;
-// if the result does not have the same value as x, the "inexact" floating-point exception is raised.
-// If the exponent is being decreased and the significand of the result has more digits than the type would allow,
-// the "invalid" floating-point exception is raised and the result is NaN.
-// If one or both operands are NaN the result is NaN.
-// Otherwise, if only one operand is infinity, the "invalid" floating-point exception is raised and the result is NaN.
-// If both operands are infinity, the result is DEC_INFINITY, with the same sign as x, converted to the type of x.
-// The quantize functions do not signal underflow.
-BOOST_DECIMAL_CUDA_CONSTEXPR auto quantized128(const decimal128_t& lhs, const decimal128_t& rhs) noexcept -> decimal128_t
-{
-    #ifndef BOOST_DECIMAL_FAST_MATH
-    // Return the correct type of nan
-    if (isnan(lhs))
-    {
-        return lhs;
-    }
-    else if (isnan(rhs))
-    {
-        return rhs;
-    }
-
-    // If one is infinity then return a signaling NAN
-    if (isinf(lhs) != isinf(rhs))
-    {
-        return boost::decimal::from_bits(boost::decimal::detail::d128_snan_mask);
-    }
-    else if (isinf(lhs) && isinf(rhs))
-    {
-        return lhs;
-    }
-    #endif
-
-    return {lhs.full_significand(), rhs.biased_exponent(), lhs.isneg()};
-}
-
 BOOST_DECIMAL_CUDA_CONSTEXPR auto copysignd128(decimal128_t mag, const decimal128_t sgn) noexcept -> decimal128_t
 {
     mag.edit_sign(sgn.isneg());

include/boost/decimal/decimal32_t.hpp

@@ -26,6 +26,7 @@
 #include <boost/decimal/detail/to_decimal.hpp>
 #include <boost/decimal/detail/promotion.hpp>
 #include <boost/decimal/detail/check_non_finite.hpp>
+#include <boost/decimal/detail/quantize_impl.hpp>
 #include <boost/decimal/detail/shrink_significand.hpp>
 #include <boost/decimal/detail/cmath/isfinite.hpp>
 #include <boost/decimal/detail/cmath/fpclassify.hpp>
@@ -564,7 +565,8 @@ BOOST_DECIMAL_EXPORT class decimal32_t final // NOLINT(cppcoreguidelines-special
     friend constexpr auto quantexpd32(decimal32_t x) noexcept -> int;
 
     // 3.6.6 Quantize
-    friend constexpr auto quantized32(decimal32_t lhs, decimal32_t rhs) noexcept -> decimal32_t;
+    template <BOOST_DECIMAL_DECIMAL_FLOATING_TYPE T>
+    friend BOOST_DECIMAL_CUDA_CONSTEXPR auto quantize(T lhs, T rhs) noexcept -> T;
 
     // <cmath> functions that need to be friends
     friend constexpr auto copysignd32(decimal32_t mag, decimal32_t sgn) noexcept -> decimal32_t;
@@ -2259,44 +2261,6 @@ constexpr auto quantexpd32(const decimal32_t x) noexcept -> int
     return static_cast<int>(x.unbiased_exponent());
 }
 
-// 3.6.6
-// Returns: a number that is equal in value (except for any rounding) and sign to x,
-// and which has an exponent set to be equal to the exponent of y.
-// If the exponent is being increased, the value is correctly rounded according to the current rounding mode;
-// if the result does not have the same value as x, the "inexact" floating-point exception is raised.
-// If the exponent is being decreased and the significand of the result has more digits than the type would allow,
-// the "invalid" floating-point exception is raised and the result is NaN.
-// If one or both operands are NaN the result is NaN.
-// Otherwise, if only one operand is infinity, the "invalid" floating-point exception is raised and the result is NaN.
-// If both operands are infinity, the result is DEC_INFINITY, with the same sign as x, converted to the type of x.
-// The quantize functions do not signal underflow.
-constexpr auto quantized32(const decimal32_t lhs, const decimal32_t rhs) noexcept -> decimal32_t
-{
-    #ifndef BOOST_DECIMAL_FAST_MATH
-    // Return the correct type of nan
-    if (isnan(lhs))
-    {
-        return lhs;
-    }
-    if (isnan(rhs))
-    {
-        return rhs;
-    }
-
-    // If one is infinity then return a signaling NAN
-    if (isinf(lhs) != isinf(rhs))
-    {
-        return from_bits(detail::d32_snan_mask);
-    }
-    if (isinf(lhs) && isinf(rhs))
-    {
-        return lhs;
-    }
-    #endif
-
-    return {lhs.full_significand(), rhs.biased_exponent(), lhs.isneg()};
-}
-
 constexpr auto scalblnd32(decimal32_t num, const long exp) noexcept -> decimal32_t
 {
     #ifndef BOOST_DECIMAL_FAST_MATH

include/boost/decimal/decimal64_t.hpp

@@ -28,6 +28,7 @@
 #include <boost/decimal/detail/comparison.hpp>
 #include <boost/decimal/detail/mixed_decimal_arithmetic.hpp>
 #include <boost/decimal/detail/check_non_finite.hpp>
+#include <boost/decimal/detail/quantize_impl.hpp>
 #include <boost/decimal/detail/shrink_significand.hpp>
 #include <boost/decimal/detail/cmath/isfinite.hpp>
 #include <boost/decimal/detail/cmath/fpclassify.hpp>
@@ -575,7 +576,8 @@ BOOST_DECIMAL_EXPORT class decimal64_t final
     friend BOOST_DECIMAL_CUDA_CONSTEXPR auto quantexpd64(decimal64_t x) noexcept -> int;
 
     // 3.6.6 Quantize
-    friend BOOST_DECIMAL_CUDA_CONSTEXPR auto quantized64(decimal64_t lhs, decimal64_t rhs) noexcept -> decimal64_t;
+    template <BOOST_DECIMAL_DECIMAL_FLOATING_TYPE T>
+    friend BOOST_DECIMAL_CUDA_CONSTEXPR auto quantize(T lhs, T rhs) noexcept -> T;
 
     // <cmath> functions that need to be friends
     template <BOOST_DECIMAL_DECIMAL_FLOATING_TYPE T>
@@ -2167,44 +2169,6 @@ BOOST_DECIMAL_CUDA_CONSTEXPR auto quantexpd64(const decimal64_t x) noexcept -> i
     return static_cast<int>(x.unbiased_exponent());
 }
 
-// 3.6.6
-// Returns: a number that is equal in value (except for any rounding) and sign to x,
-// and which has an exponent set to be equal to the exponent of y.
-// If the exponent is being increased, the value is correctly rounded according to the current rounding mode;
-// if the result does not have the same value as x, the "inexact" floating-point exception is raised.
-// If the exponent is being decreased and the significand of the result has more digits than the type would allow,
-// the "invalid" floating-point exception is raised and the result is NaN.
-// If one or both operands are NaN the result is NaN.
-// Otherwise, if only one operand is infinity, the "invalid" floating-point exception is raised and the result is NaN.
-// If both operands are infinity, the result is DEC_INFINITY, with the same sign as x, converted to the type of x.
-// The quantize functions do not signal underflow.
-BOOST_DECIMAL_CUDA_CONSTEXPR auto quantized64(const decimal64_t lhs, const decimal64_t rhs) noexcept -> decimal64_t
-{
-    #ifndef BOOST_DECIMAL_FAST_MATH
-    // Return the correct type of nan
-    if (isnan(lhs))
-    {
-        return lhs;
-    }
-    if (isnan(rhs))
-    {
-        return rhs;
-    }
-
-    // If one is infinity then return a signaling NAN
-    if (isinf(lhs) != isinf(rhs))
-    {
-        return boost::decimal::from_bits(boost::decimal::detail::d64_snan_mask);
-    }
-    if (isinf(lhs) && isinf(rhs))
-    {
-        return lhs;
-    }
-    #endif
-
-    return {lhs.full_significand(), rhs.biased_exponent(), lhs.isneg()};
-}
-
 BOOST_DECIMAL_CUDA_CONSTEXPR auto scalblnd64(decimal64_t num, const long exp) noexcept -> decimal64_t
 {
     #ifndef BOOST_DECIMAL_FAST_MATH

include/boost/decimal/decimal_fast128_t.hpp

@@ -26,6 +26,7 @@
 #include <boost/decimal/detail/to_decimal.hpp>
 #include <boost/decimal/detail/promotion.hpp>
 #include <boost/decimal/detail/check_non_finite.hpp>
+#include <boost/decimal/detail/quantize_impl.hpp>
 #include <boost/decimal/detail/shrink_significand.hpp>
 #include <boost/decimal/detail/cmath/isfinite.hpp>
 #include <boost/decimal/detail/cmath/fpclassify.hpp>
@@ -499,7 +500,8 @@ BOOST_DECIMAL_EXPORT class alignas(16) decimal_fast128_t final
     friend constexpr auto quantexpd128f(const decimal_fast128_t& x) noexcept -> int;
 
     // 3.6.6 Quantize
-    friend constexpr auto quantized128f(const decimal_fast128_t& lhs, const decimal_fast128_t& rhs) noexcept -> decimal_fast128_t;
+    template <BOOST_DECIMAL_DECIMAL_FLOATING_TYPE T>
+    friend BOOST_DECIMAL_CUDA_CONSTEXPR auto quantize(T lhs, T rhs) noexcept -> T;
 };
 
 #ifdef _MSC_VER
@@ -1696,44 +1698,6 @@ constexpr auto quantexpd128f(const decimal_fast128_t& x) noexcept -> int
     return static_cast<int>(x.unbiased_exponent());
 }
 
-// 3.6.6
-// Returns: a number that is equal in value (except for any rounding) and sign to x,
-// and which has an exponent set to be equal to the exponent of y.
-// If the exponent is being increased, the value is correctly rounded according to the current rounding mode;
-// if the result does not have the same value as x, the "inexact" floating-point exception is raised.
-// If the exponent is being decreased and the significand of the result has more digits than the type would allow,
-// the "invalid" floating-point exception is raised and the result is NaN.
-// If one or both operands are NaN the result is NaN.
-// Otherwise, if only one operand is infinity, the "invalid" floating-point exception is raised and the result is NaN.
-// If both operands are infinity, the result is DEC_INFINITY, with the same sign as x, converted to the type of x.
-// The quantize functions do not signal underflow.
-constexpr auto quantized128f(const decimal_fast128_t& lhs, const decimal_fast128_t& rhs) noexcept -> decimal_fast128_t
-{
-    #ifndef BOOST_DECIMAL_FAST_MATH
-    // Return the correct type of nan
-    if (isnan(lhs))
-    {
-        return lhs;
-    }
-    else if (isnan(rhs))
-    {
-        return rhs;
-    }
-
-    // If one is infinity then return a signaling NAN
-    if (isinf(lhs) != isinf(rhs))
-    {
-        return boost::decimal::direct_init_d128(boost::decimal::detail::d128_fast_qnan, 0, false);
-    }
-    else if (isinf(lhs) && isinf(rhs))
-    {
-        return lhs;
-    }
-    #endif
-
-    return {lhs.full_significand(), rhs.biased_exponent(), lhs.isneg()};
-}
-
 #if !defined(BOOST_DECIMAL_DISABLE_CLIB)
 
 constexpr decimal_fast128_t::decimal_fast128_t(const char* str, const std::size_t len)

include/boost/decimal/decimal_fast32_t.hpp

@@ -26,6 +26,7 @@
 #include <boost/decimal/detail/to_decimal.hpp>
 #include <boost/decimal/detail/promotion.hpp>
 #include <boost/decimal/detail/check_non_finite.hpp>
+#include <boost/decimal/detail/quantize_impl.hpp>
 #include <boost/decimal/detail/shrink_significand.hpp>
 #include <boost/decimal/detail/cmath/isfinite.hpp>
 #include <boost/decimal/detail/cmath/fpclassify.hpp>
@@ -497,7 +498,8 @@ BOOST_DECIMAL_EXPORT class alignas(4) decimal_fast32_t final
     // Specific decimal functionality
     friend constexpr auto samequantumd32f(decimal_fast32_t lhs, decimal_fast32_t rhs) noexcept -> bool;
     friend constexpr auto quantexpd32f(decimal_fast32_t x) noexcept -> int;
-    friend constexpr auto quantized32f(decimal_fast32_t lhs, decimal_fast32_t rhs) noexcept -> decimal_fast32_t;
+    template <BOOST_DECIMAL_DECIMAL_FLOATING_TYPE T>
+    friend BOOST_DECIMAL_CUDA_CONSTEXPR auto quantize(T lhs, T rhs) noexcept -> T;
 };
 
 #ifdef _MSC_VER
@@ -1684,43 +1686,6 @@ constexpr auto quantexpd32f(const decimal_fast32_t x) noexcept -> int
     return static_cast<int>(x.unbiased_exponent());
 }
 
-// Returns: a number that is equal in value (except for any rounding) and sign to x,
-// and which has an exponent set to be equal to the exponent of y.
-// If the exponent is being increased, the value is correctly rounded according to the current rounding mode;
-// if the result does not have the same value, as x, the "inexact" floating-point exception is raised.
-// If the exponent is being decreased and the significand of the result has more digits than the type would allow,
-// the "invalid" floating-point exception is raised and the result is NaN.
-// If one or both operands are NaN, the result is NaN.
-// Otherwise, if only one operand is infinity, the "invalid" floating-point exception is raised and the result is NaN.
-// If both operands are infinity, the result is DEC_INFINITY, with the same sign as x, converted to the type of x.
-// The quantize functions do not signal underflow.
-constexpr auto quantized32f(const decimal_fast32_t lhs, const decimal_fast32_t rhs) noexcept -> decimal_fast32_t
-{
-    #ifndef BOOST_DECIMAL_FAST_MATH
-    // Return the correct type of nan
-    if (isnan(lhs))
-    {
-        return lhs;
-    }
-    else if (isnan(rhs))
-    {
-        return rhs;
-    }
-
-    // If one is infinity then return a signaling NAN
-    if (isinf(lhs) != isinf(rhs))
-    {
-        return direct_init(detail::d32_fast_snan, UINT8_C(0));
-    }
-    else if (isinf(lhs) && isinf(rhs))
-    {
-        return lhs;
-    }
-    #endif
-
-    return {lhs.full_significand(), rhs.biased_exponent(), lhs.isneg()};
-}
-
 #if !defined(BOOST_DECIMAL_DISABLE_CLIB)
 
 constexpr decimal_fast32_t::decimal_fast32_t(const char* str, const std::size_t len)