[v3,1/2] libcamera: libipa: Add right-shift operators to Vector
diff mbox series

Message ID 20260511-libipa-vector-rshift-v3-1-a275f6e87ec4@jetm.me
State New
Headers show
Series
  • libcamera: Vector right-shift operators and SwStatsCpu use site
Related show

Commit Message

Javier Tia May 11, 2026, 8:23 p.m. UTC 
Add operator>> and operator>>= for right-shifting all elements by a
scalar shift amount. Both operate element-wise: operator>> returns a
new Vector with each element shifted, operator>>= shifts in place and
returns a reference to *this.

The motivating use case is SwStatsCpu::finishFrame(), which right-shifts
three individual components of the RGB sum by the same sumShift_ value.
With these operators that becomes a single sum_ >>= sumShift_ expression.

The private apply() helpers for non-mutating and mutating scalar
operations are templated on the scalar type so the existing operators
keep working with T while shift can pass an unsigned int. A
static_assert in each shift operator restricts them to integer element
types since right-shift is undefined on floating-point Vectors.

Suggested-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>
Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Javier Tia <floss@jetm.me>
Reviewed-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>
---
 include/libcamera/internal/vector.h | 22 ++++++++++++++++++----
 src/libcamera/vector.cpp            | 14 ++++++++++++++
 test/vector.cpp                     |  5 +++++
 3 files changed, 37 insertions(+), 4 deletions(-)

Patch
diff mbox series 

diff --git a/include/libcamera/internal/vector.h b/include/libcamera/internal/vector.h
index ed7490e1..e3ea723d 100644
--- a/include/libcamera/internal/vector.h
+++ b/include/libcamera/internal/vector.h
@@ -111,6 +111,13 @@  public:
 		return apply(*this, scalar, std::divides<>{});
 	}
 
+	constexpr Vector operator>>(unsigned int shift) const
+	{
+		static_assert(std::is_integral_v<T>,
+			      "Vector::operator>> requires an integer element type");
+		return apply(*this, shift, [](T a, unsigned int b) { return a >> b; });
+	}
+
 	Vector &operator+=(const Vector &other)
 	{
 		return apply(other, [](T a, T b) { return a + b; });
@@ -151,6 +158,13 @@  public:
 		return apply(scalar, [](T a, T b) { return a / b; });
 	}
 
+	Vector &operator>>=(unsigned int shift)
+	{
+		static_assert(std::is_integral_v<T>,
+			      "Vector::operator>>= requires an integer element type");
+		return apply(shift, [](T a, unsigned int b) { return a >> b; });
+	}
+
 	constexpr Vector min(const Vector &other) const
 	{
 		return apply(*this, other, [](T a, T b) { return std::min(a, b); });
@@ -260,8 +274,8 @@  private:
 		return result;
 	}
 
-	template<class BinaryOp>
-	static constexpr Vector apply(const Vector &lhs, T rhs, BinaryOp op)
+	template<class U, class BinaryOp>
+	static constexpr Vector apply(const Vector &lhs, U rhs, BinaryOp op)
 	{
 		Vector result;
 		std::transform(lhs.data_.begin(), lhs.data_.end(),
@@ -281,8 +295,8 @@  private:
 		return *this;
 	}
 
-	template<class BinaryOp>
-	Vector &apply(T scalar, BinaryOp op)
+	template<class U, class BinaryOp>
+	Vector &apply(U scalar, BinaryOp op)
 	{
 		std::for_each(data_.begin(), data_.end(),
 			      [&op, scalar](T &v) { v = op(v, scalar); });
diff --git a/src/libcamera/vector.cpp b/src/libcamera/vector.cpp
index 86b9f9bb..94fbf61e 100644
--- a/src/libcamera/vector.cpp
+++ b/src/libcamera/vector.cpp
@@ -126,6 +126,13 @@  LOG_DEFINE_CATEGORY(Vector)
  * \return The element-wise division of this vector by \a scalar
  */
 
+/**
+ * \fn Vector::operator>>(unsigned int shift) const
+ * \brief Right-shift each element of this vector by \a shift bits
+ * \param[in] shift The shift amount
+ * \return A new vector with each element right-shifted by \a shift
+ */
+
 /**
  * \fn Vector::operator+=(Vector const &other)
  * \brief Add \a other element-wise to this vector
@@ -182,6 +189,13 @@  LOG_DEFINE_CATEGORY(Vector)
  * \return This vector
  */
 
+/**
+ * \fn Vector::operator>>=(unsigned int shift)
+ * \brief Right-shift each element of this vector by \a shift bits in place
+ * \param[in] shift The shift amount
+ * \return This vector
+ */
+
 /**
  * \fn Vector::min(const Vector &other) const
  * \brief Calculate the minimum of this vector and \a other element-wise
diff --git a/test/vector.cpp b/test/vector.cpp
index 4fae960d..4ff908e8 100644
--- a/test/vector.cpp
+++ b/test/vector.cpp
@@ -93,6 +93,11 @@  protected:
 		v2 /= 4.0;
 		ASSERT_EQ(v2, (Vector<double, 3>{{ 1.0, 4.0, 8.0 }}));
 
+		Vector<int, 3> vi{{ 8, 16, 32 }};
+		ASSERT_EQ(vi >> 2, (Vector<int, 3>{{ 2, 4, 8 }}));
+		vi >>= 1;
+		ASSERT_EQ(vi, (Vector<int, 3>{{ 4, 8, 16 }}));
+
 		return TestPass;
 	}
 };