1 files changed, 51 insertions, 0 deletions
diff --git a/src/ipa/libipa/histogram.h b/src/ipa/libipa/histogram.h
new file mode 100644
index 00000000..a926002c
--- /dev/null
+++ b/src/ipa/libipa/histogram.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+/*
+ * Copyright (C) 2019, Raspberry Pi Ltd
+ *
+ * histogram calculation interface
+ */
+
+#pragma once
+
+#include <limits.h>
+#include <stdint.h>
+#include <type_traits>
+#include <vector>
+
+#include <libcamera/base/span.h>
+#include <libcamera/base/utils.h>
+
+namespace libcamera {
+
+namespace ipa {
+
+class Histogram
+{
+public:
+	Histogram() { cumulative_.push_back(0); }
+	Histogram(Span<const uint32_t> data);
+
+	template<typename Transform,
+		 std::enable_if_t<std::is_invocable_v<Transform, uint32_t>> * = nullptr>
+	Histogram(Span<const uint32_t> data, Transform transform)
+	{
+		cumulative_.resize(data.size() + 1);
+		cumulative_[0] = 0;
+		for (const auto &[i, value] : utils::enumerate(data))
+			cumulative_[i + 1] = cumulative_[i] + transform(value);
+	}
+
+	size_t bins() const { return cumulative_.size() - 1; }
+	const Span<const uint64_t> data() const { return cumulative_; }
+	uint64_t total() const { return cumulative_[cumulative_.size() - 1]; }
+	uint64_t cumulativeFrequency(double bin) const;
+	double quantile(double q, uint32_t first = 0, uint32_t last = UINT_MAX) const;
+	double interQuantileMean(double lowQuantile, double hiQuantile) const;
+
+private:
+	std::vector<uint64_t> cumulative_;
+};
+
+} /* namespace ipa */
+
+} /* namespace libcamera */