1 files changed, 16 insertions, 3 deletions
diff --git a/src/ipa/libipa/histogram.h b/src/ipa/libipa/histogram.h
index 05bb4b80..a926002c 100644
--- a/src/ipa/libipa/histogram.h
+++ b/src/ipa/libipa/histogram.h
@@ -2,18 +2,18 @@
 /*
  * Copyright (C) 2019, Raspberry Pi Ltd
  *
- * histogram.h - histogram calculation interface
+ * histogram calculation interface
  */
 
 #pragma once
 
-#include <assert.h>
 #include <limits.h>
 #include <stdint.h>
-
+#include <type_traits>
 #include <vector>
 
 #include <libcamera/base/span.h>
+#include <libcamera/base/utils.h>
 
 namespace libcamera {
 
@@ -22,8 +22,21 @@ 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;