From e0909fedfe465ccb0628d11af442c8e15cd040d0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vladim=C3=ADr=20Vondru=C5=A1?= <mosra@centrum.cz>
Date: Tue, 17 May 2022 15:49:51 +0200
Subject: [PATCH] Math: add castInto() variants for Double<->integer.

Because yes of course dealing with a JSON just isn't possible
without having to make decisions between insufficiently imprecise
integers and unnecessarly overprecise doubles.
---
 doc/changelog.dox                         |   4 +-
 src/Magnum/Math/PackingBatch.cpp          |  48 +++++++++++
 src/Magnum/Math/PackingBatch.h            | 100 ++++++++++++++++++++++
 src/Magnum/Math/Test/PackingBatchTest.cpp |  96 ++++++++++++---------
 4 files changed, 204 insertions(+), 44 deletions(-)

diff --git a/doc/changelog.dox b/doc/changelog.dox
index 2dda148bc..0052d95bf 100644
--- a/doc/changelog.dox
+++ b/doc/changelog.dox
@@ -379,8 +379,8 @@ See also:
 
 -   Added @ref Math::castInto() overloads for casting between @ref UnsignedByte
     and @ref UnsignedShort or @ref Byte and @ref Short, from and to
-    @ref UnsignedLong / @ref Long, and for casting between @ref Float and
-    @ref Double
+    @ref UnsignedLong / @ref Long, between integral types and @ref Double and
+    for casting between @ref Float and @ref Double
 -   @ref Math::RectangularMatrix is now explicitly convertible from matrices of
     different sizes, with a possibility to specify whether to fill the diagonal
     or leave it as zeros. This was originally available only on (square)
diff --git a/src/Magnum/Math/PackingBatch.cpp b/src/Magnum/Math/PackingBatch.cpp
index a72042595..57a59798e 100644
--- a/src/Magnum/Math/PackingBatch.cpp
+++ b/src/Magnum/Math/PackingBatch.cpp
@@ -216,6 +216,30 @@ void castInto(const Corrade::Containers::StridedArrayView2D<const Int>& src, con
     castIntoImplementation(src, dst);
 }
 
+void castInto(const Corrade::Containers::StridedArrayView2D<const UnsignedByte>& src, const Corrade::Containers::StridedArrayView2D<Double>& dst) {
+    castIntoImplementation(src, dst);
+}
+
+void castInto(const Corrade::Containers::StridedArrayView2D<const Byte>& src, const Corrade::Containers::StridedArrayView2D<Double>& dst) {
+    castIntoImplementation(src, dst);
+}
+
+void castInto(const Corrade::Containers::StridedArrayView2D<const UnsignedShort>& src, const Corrade::Containers::StridedArrayView2D<Double>& dst) {
+    castIntoImplementation(src, dst);
+}
+
+void castInto(const Corrade::Containers::StridedArrayView2D<const Short>& src, const Corrade::Containers::StridedArrayView2D<Double>& dst) {
+    castIntoImplementation(src, dst);
+}
+
+void castInto(const Corrade::Containers::StridedArrayView2D<const UnsignedInt>& src, const Corrade::Containers::StridedArrayView2D<Double>& dst) {
+    castIntoImplementation(src, dst);
+}
+
+void castInto(const Corrade::Containers::StridedArrayView2D<const Int>& src, const Corrade::Containers::StridedArrayView2D<Double>& dst) {
+    castIntoImplementation(src, dst);
+}
+
 void castInto(const Corrade::Containers::StridedArrayView2D<const Float>& src, const Corrade::Containers::StridedArrayView2D<UnsignedByte>& dst) {
     castIntoImplementation(src, dst);
 }
@@ -240,6 +264,30 @@ void castInto(const Corrade::Containers::StridedArrayView2D<const Float>& src, c
     castIntoImplementation(src, dst);
 }
 
+void castInto(const Corrade::Containers::StridedArrayView2D<const Double>& src, const Corrade::Containers::StridedArrayView2D<UnsignedByte>& dst) {
+    castIntoImplementation(src, dst);
+}
+
+void castInto(const Corrade::Containers::StridedArrayView2D<const Double>& src, const Corrade::Containers::StridedArrayView2D<Byte>& dst) {
+    castIntoImplementation(src, dst);
+}
+
+void castInto(const Corrade::Containers::StridedArrayView2D<const Double>& src, const Corrade::Containers::StridedArrayView2D<UnsignedShort>& dst) {
+    castIntoImplementation(src, dst);
+}
+
+void castInto(const Corrade::Containers::StridedArrayView2D<const Double>& src, const Corrade::Containers::StridedArrayView2D<Short>& dst) {
+    castIntoImplementation(src, dst);
+}
+
+void castInto(const Corrade::Containers::StridedArrayView2D<const Double>& src, const Corrade::Containers::StridedArrayView2D<UnsignedInt>& dst) {
+    castIntoImplementation(src, dst);
+}
+
+void castInto(const Corrade::Containers::StridedArrayView2D<const Double>& src, const Corrade::Containers::StridedArrayView2D<Int>& dst) {
+    castIntoImplementation(src, dst);
+}
+
 void castInto(const Corrade::Containers::StridedArrayView2D<const UnsignedByte>& src, const Corrade::Containers::StridedArrayView2D<UnsignedShort>& dst) {
     castIntoImplementation(src, dst);
 }
diff --git a/src/Magnum/Math/PackingBatch.h b/src/Magnum/Math/PackingBatch.h
index ce5d76021..403c817b4 100644
--- a/src/Magnum/Math/PackingBatch.h
+++ b/src/Magnum/Math/PackingBatch.h
@@ -215,6 +215,56 @@ MAGNUM_EXPORT void castInto(const Corrade::Containers::StridedArrayView2D<const
  */
 MAGNUM_EXPORT void castInto(const Corrade::Containers::StridedArrayView2D<const Int>& src, const Corrade::Containers::StridedArrayView2D<Float>& dst);
 
+/**
+@brief Cast integer values into a 64-bit floating-point representation
+@param[in]  src     Source integral values
+@param[out] dst     Destination float values
+@m_since_latest
+
+Unlike @ref packInto(), this function performs only an equivalent of
+@cpp Double(a) @ce over the range, so e.g. @cpp 135 @ce becomes @cpp 135.0 @ce.
+Second dimension is meant to contain vector/matrix components, or have a size
+of 1 for scalars. Expects that @p src and @p dst have the same size and that
+the second dimension in both is contiguous.
+
+@attention Numbers with more than 52 bits of precision will not be represented
+    accurately when cast into a @relativeref{Magnum,Double}.
+
+@see @ref castInto(const Corrade::Containers::StridedArrayView2D<const Double>&, const Corrade::Containers::StridedArrayView2D<UnsignedByte>&),
+    @ref Corrade::Containers::StridedArrayView::isContiguous()
+*/
+MAGNUM_EXPORT void castInto(const Corrade::Containers::StridedArrayView2D<const UnsignedByte>& src, const Corrade::Containers::StridedArrayView2D<Double>& dst);
+
+/**
+ * @overload
+ * @m_since_latest
+ */
+MAGNUM_EXPORT void castInto(const Corrade::Containers::StridedArrayView2D<const Byte>& src, const Corrade::Containers::StridedArrayView2D<Double>& dst);
+
+/**
+ * @overload
+ * @m_since_latest
+ */
+MAGNUM_EXPORT void castInto(const Corrade::Containers::StridedArrayView2D<const UnsignedShort>& src, const Corrade::Containers::StridedArrayView2D<Double>& dst);
+
+/**
+ * @overload
+ * @m_since_latest
+ */
+MAGNUM_EXPORT void castInto(const Corrade::Containers::StridedArrayView2D<const Short>& src, const Corrade::Containers::StridedArrayView2D<Double>& dst);
+
+/**
+ * @overload
+ * @m_since_latest
+ */
+MAGNUM_EXPORT void castInto(const Corrade::Containers::StridedArrayView2D<const UnsignedInt>& src, const Corrade::Containers::StridedArrayView2D<Double>& dst);
+
+/**
+ * @overload
+ * @m_since_latest
+ */
+MAGNUM_EXPORT void castInto(const Corrade::Containers::StridedArrayView2D<const Int>& src, const Corrade::Containers::StridedArrayView2D<Double>& dst);
+
 /**
 @brief Cast 32-bit floating-point values into an integer representation
 @param[in]  src     Source float values
@@ -265,6 +315,56 @@ MAGNUM_EXPORT void castInto(const Corrade::Containers::StridedArrayView2D<const
  */
 MAGNUM_EXPORT void castInto(const Corrade::Containers::StridedArrayView2D<const Float>& src, const Corrade::Containers::StridedArrayView2D<Int>& dst);
 
+/**
+@brief Cast 64-bit floating-point values into an integer representation
+@param[in]  src     Source double values
+@param[out] dst     Destination integral values
+@m_since_latest
+
+Unlike @ref packInto(), this function performs only an equivalent of
+@cpp T(a) @ce over the range, so e.g. @cpp 135.0 @ce becomes @cpp 135 @ce.
+Second dimension is meant to contain vector/matrix components, or have a size
+of 1 for scalars. Expects that @p src and @p dst have the same size and that
+the second dimension in both is contiguous.
+
+@attention Fractional part of the @relativeref{Magnum,Double} input will be
+    silently discarded when cast into an integer type.
+
+@see @ref castInto(const Corrade::Containers::StridedArrayView2D<const UnsignedByte>&, const Corrade::Containers::StridedArrayView2D<Double>&),
+    @ref Corrade::Containers::StridedArrayView::isContiguous()
+*/
+MAGNUM_EXPORT void castInto(const Corrade::Containers::StridedArrayView2D<const Double>& src, const Corrade::Containers::StridedArrayView2D<UnsignedByte>& dst);
+
+/**
+ * @overload
+ * @m_since_latest
+ */
+MAGNUM_EXPORT void castInto(const Corrade::Containers::StridedArrayView2D<const Double>& src, const Corrade::Containers::StridedArrayView2D<Byte>& dst);
+
+/**
+ * @overload
+ * @m_since_latest
+ */
+MAGNUM_EXPORT void castInto(const Corrade::Containers::StridedArrayView2D<const Double>& src, const Corrade::Containers::StridedArrayView2D<UnsignedShort>& dst);
+
+/**
+ * @overload
+ * @m_since_latest
+ */
+MAGNUM_EXPORT void castInto(const Corrade::Containers::StridedArrayView2D<const Double>& src, const Corrade::Containers::StridedArrayView2D<Short>& dst);
+
+/**
+ * @overload
+ * @m_since_latest
+ */
+MAGNUM_EXPORT void castInto(const Corrade::Containers::StridedArrayView2D<const Double>& src, const Corrade::Containers::StridedArrayView2D<UnsignedInt>& dst);
+
+/**
+ * @overload
+ * @m_since_latest
+ */
+MAGNUM_EXPORT void castInto(const Corrade::Containers::StridedArrayView2D<const Double>& src, const Corrade::Containers::StridedArrayView2D<Int>& dst);
+
 /**
 @brief Cast integer values into a differently sized type
 @param[in]  src     Source values
diff --git a/src/Magnum/Math/Test/PackingBatchTest.cpp b/src/Magnum/Math/Test/PackingBatchTest.cpp
index d5828f6f8..641efa867 100644
--- a/src/Magnum/Math/Test/PackingBatchTest.cpp
+++ b/src/Magnum/Math/Test/PackingBatchTest.cpp
@@ -51,8 +51,8 @@ struct PackingBatchTest: Corrade::TestSuite::Tester {
     void unpackHalf();
     void packHalf();
 
-    template<class T> void castUnsignedFloat();
-    template<class T> void castSignedFloat();
+    template<class FloatingPoint, class Integral> void castUnsignedFloatingPoint();
+    template<class FloatingPoint, class Integral> void castSignedFloatingPoint();
 
     template<class T, class U> void castUnsignedInteger();
     template<class T, class U> void castSignedInteger();
@@ -77,12 +77,18 @@ PackingBatchTest::PackingBatchTest() {
               &PackingBatchTest::unpackHalf,
               &PackingBatchTest::packHalf,
 
-              &PackingBatchTest::castUnsignedFloat<UnsignedByte>,
-              &PackingBatchTest::castUnsignedFloat<UnsignedShort>,
-              &PackingBatchTest::castUnsignedFloat<UnsignedInt>,
-              &PackingBatchTest::castSignedFloat<Byte>,
-              &PackingBatchTest::castSignedFloat<Short>,
-              &PackingBatchTest::castSignedFloat<Int>,
+              &PackingBatchTest::castUnsignedFloatingPoint<Float, UnsignedByte>,
+              &PackingBatchTest::castUnsignedFloatingPoint<Float, UnsignedShort>,
+              &PackingBatchTest::castUnsignedFloatingPoint<Float, UnsignedInt>,
+              &PackingBatchTest::castUnsignedFloatingPoint<Double, UnsignedByte>,
+              &PackingBatchTest::castUnsignedFloatingPoint<Double, UnsignedShort>,
+              &PackingBatchTest::castUnsignedFloatingPoint<Double, UnsignedInt>,
+              &PackingBatchTest::castSignedFloatingPoint<Float, Byte>,
+              &PackingBatchTest::castSignedFloatingPoint<Float, Short>,
+              &PackingBatchTest::castSignedFloatingPoint<Float, Int>,
+              &PackingBatchTest::castSignedFloatingPoint<Double, Byte>,
+              &PackingBatchTest::castSignedFloatingPoint<Double, Short>,
+              &PackingBatchTest::castSignedFloatingPoint<Double, Int>,
 
               &PackingBatchTest::castUnsignedInteger<UnsignedByte, UnsignedShort>,
               &PackingBatchTest::castUnsignedInteger<UnsignedByte, UnsignedInt>,
@@ -109,6 +115,12 @@ PackingBatchTest::PackingBatchTest() {
               &PackingBatchTest::assertionsCast<Float, Short>,
               &PackingBatchTest::assertionsCast<Float, UnsignedInt>,
               &PackingBatchTest::assertionsCast<Float, Int>,
+              &PackingBatchTest::assertionsCast<Double, UnsignedByte>,
+              &PackingBatchTest::assertionsCast<Double, Byte>,
+              &PackingBatchTest::assertionsCast<Double, UnsignedShort>,
+              &PackingBatchTest::assertionsCast<Double, Short>,
+              &PackingBatchTest::assertionsCast<Double, UnsignedInt>,
+              &PackingBatchTest::assertionsCast<Double, Int>,
               &PackingBatchTest::assertionsCast<UnsignedShort, UnsignedByte>,
               &PackingBatchTest::assertionsCast<UnsignedInt, UnsignedByte>,
               &PackingBatchTest::assertionsCast<UnsignedInt, UnsignedShort>,
@@ -433,12 +445,12 @@ void PackingBatchTest::packHalf() {
         CORRADE_COMPARE(Math::packHalf(data[i].src), data[i].dst);
 }
 
-template<class T> void PackingBatchTest::castUnsignedFloat() {
-    setTestCaseTemplateName(TypeTraits<T>::name());
+template<class FloatingPoint, class Integral> void PackingBatchTest::castUnsignedFloatingPoint() {
+    setTestCaseTemplateName({TypeTraits<FloatingPoint>::name(), TypeTraits<Integral>::name()});
 
     struct Data {
-        Math::Vector2<T> src;
-        Vector2 dst;
+        Math::Vector2<Integral> src;
+        Math::Vector2<FloatingPoint> dst;
     } data[]{
         {{0, 89}, {}},
         {{149, 22}, {}},
@@ -447,38 +459,38 @@ template<class T> void PackingBatchTest::castUnsignedFloat() {
 
     /* GCC 4.8 doesn't like constexpr here (cannot initialize aggregate of type
        ‘const Vector2 [3]’ with a compound literal), wtf */
-    const Vector2 expectedFloat[] {
-        {0.0f, 89.0f},
-        {149.0f, 22.0f},
-        {13.0f, 255.0f}
+    const Math::Vector2<FloatingPoint> expectedFloatingPoint[] {
+        {FloatingPoint(0.0), FloatingPoint(89.0)},
+        {FloatingPoint(149.0), FloatingPoint(22.0)},
+        {FloatingPoint(13.0), FloatingPoint(255.0)}
     };
 
-    constexpr Math::Vector2<T> expectedInteger[] {
+    constexpr Math::Vector2<Integral> expectedIntegral[] {
         {0, 89},
         {149, 22},
         {13, 255}
     };
 
-    Corrade::Containers::StridedArrayView1D<Math::Vector2<T>> src{data, &data[0].src, 3, sizeof(Data)};
-    Corrade::Containers::StridedArrayView1D<Vector2> dst{data, &data[0].dst, 3, sizeof(Data)};
-    castInto(Corrade::Containers::arrayCast<2, T>(src),
-             Corrade::Containers::arrayCast<2, Float>(dst));
-    CORRADE_COMPARE_AS(dst, Corrade::Containers::stridedArrayView(expectedFloat),
+    Corrade::Containers::StridedArrayView1D<Math::Vector2<Integral>> src{data, &data[0].src, 3, sizeof(Data)};
+    Corrade::Containers::StridedArrayView1D<Math::Vector2<FloatingPoint>> dst{data, &data[0].dst, 3, sizeof(Data)};
+    castInto(Corrade::Containers::arrayCast<2, Integral>(src),
+             Corrade::Containers::arrayCast<2, FloatingPoint>(dst));
+    CORRADE_COMPARE_AS(dst, Corrade::Containers::stridedArrayView(expectedFloatingPoint),
         Corrade::TestSuite::Compare::Container);
 
     /* Test the other way around as well */
-    castInto(Corrade::Containers::arrayCast<2, Float>(dst),
-             Corrade::Containers::arrayCast<2, T>(src));
-    CORRADE_COMPARE_AS(src, Corrade::Containers::stridedArrayView(expectedInteger),
+    castInto(Corrade::Containers::arrayCast<2, FloatingPoint>(dst),
+             Corrade::Containers::arrayCast<2, Integral>(src));
+    CORRADE_COMPARE_AS(src, Corrade::Containers::stridedArrayView(expectedIntegral),
         Corrade::TestSuite::Compare::Container);
 }
 
-template<class T> void PackingBatchTest::castSignedFloat() {
-    setTestCaseTemplateName(TypeTraits<T>::name());
+template<class FloatingPoint, class Integral> void PackingBatchTest::castSignedFloatingPoint() {
+    setTestCaseTemplateName({TypeTraits<FloatingPoint>::name(), TypeTraits<Integral>::name()});
 
     struct Data {
-        Math::Vector2<T> src;
-        Vector2 dst;
+        Math::Vector2<Integral> src;
+        Math::Vector2<FloatingPoint> dst;
     } data[]{
         {{0, -89}, {}},
         {{-119, 22}, {}},
@@ -487,29 +499,29 @@ template<class T> void PackingBatchTest::castSignedFloat() {
 
     /* GCC 4.8 doesn't like constexpr here (cannot initialize aggregate of type
        ‘const Vector2 [3]’ with a compound literal), wtf */
-    const Vector2 expectedFloat[] {
-        {0.0f, -89.0f},
-        {-119.0f, 22.0f},
-        {13.0f, 127.0f}
+    const Math::Vector2<FloatingPoint> expectedFloatingPoint[] {
+        {FloatingPoint(0.0), FloatingPoint(-89.0)},
+        {FloatingPoint(-119.0), FloatingPoint(22.0)},
+        {FloatingPoint(13.0), FloatingPoint(127.0)}
     };
 
-    constexpr Math::Vector2<T> expectedInteger[] {
+    constexpr Math::Vector2<Integral> expectedIntegral[] {
         {0, -89},
         {-119, 22},
         {13, 127}
     };
 
-    Corrade::Containers::StridedArrayView1D<Math::Vector2<T>> src{data, &data[0].src, 3, sizeof(Data)};
-    Corrade::Containers::StridedArrayView1D<Vector2> dst{data, &data[0].dst, 3, sizeof(Data)};
-    castInto(Corrade::Containers::arrayCast<2, T>(src),
-             Corrade::Containers::arrayCast<2, Float>(dst));
-    CORRADE_COMPARE_AS(dst, Corrade::Containers::stridedArrayView(expectedFloat),
+    Corrade::Containers::StridedArrayView1D<Math::Vector2<Integral>> src{data, &data[0].src, 3, sizeof(Data)};
+    Corrade::Containers::StridedArrayView1D<Math::Vector2<FloatingPoint>> dst{data, &data[0].dst, 3, sizeof(Data)};
+    castInto(Corrade::Containers::arrayCast<2, Integral>(src),
+             Corrade::Containers::arrayCast<2, FloatingPoint>(dst));
+    CORRADE_COMPARE_AS(dst, Corrade::Containers::stridedArrayView(expectedFloatingPoint),
         Corrade::TestSuite::Compare::Container);
 
     /* Test the other way around as well */
-    castInto(Corrade::Containers::arrayCast<2, Float>(dst),
-             Corrade::Containers::arrayCast<2, T>(src));
-    CORRADE_COMPARE_AS(src, Corrade::Containers::stridedArrayView(expectedInteger),
+    castInto(Corrade::Containers::arrayCast<2, FloatingPoint>(dst),
+             Corrade::Containers::arrayCast<2, Integral>(src));
+    CORRADE_COMPARE_AS(src, Corrade::Containers::stridedArrayView(expectedIntegral),
         Corrade::TestSuite::Compare::Container);
 }