[libcamera-devel] [PATCH 03/20] libcamera: utils: Add alignUp and alignDown functions

[Jacopo Mondi]

Add to libcamera utils library two functions to round up or down a
value to an alignment and add a test in test/utils.cpp for the two
new functions.

Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
---
 include/libcamera/internal/utils.h |  3 +++
 src/libcamera/utils.cpp            | 22 ++++++++++++++++++++++
 test/utils.cpp                     | 18 ++++++++++++++++++
 3 files changed, 43 insertions(+)

diff --git a/include/libcamera/internal/utils.h b/include/libcamera/internal/utils.h
index 8d026cc6c0fe..25eb24ec2d16 100644
--- a/include/libcamera/internal/utils.h
+++ b/include/libcamera/internal/utils.h
@@ -200,6 +200,9 @@ details::StringSplitter split(const std::string &str, const std::string &delim);
 std::string libcameraBuildPath();
 std::string libcameraSourcePath();
 
+unsigned int alignUp(unsigned int value, unsigned int alignment);
+unsigned int alignDown(unsigned int value, unsigned int alignment);
+
 } /* namespace utils */
 
 } /* namespace libcamera */
diff --git a/src/libcamera/utils.cpp b/src/libcamera/utils.cpp
index 0567328fe31b..52fb0bb171d8 100644
--- a/src/libcamera/utils.cpp
+++ b/src/libcamera/utils.cpp
@@ -444,6 +444,28 @@ std::string libcameraSourcePath()
 	return path + "/";
 }
 
+/**
+ * \brief Align \a value to \a alignment
+ * \param[in] value The value to align
+ * \param[in] alignment The alignment
+ * \return The value rounded up to the nearest multiple of \a alignment
+ */
+unsigned int alignUp(unsigned int value, unsigned int alignment)
+{
+	return (value + alignment - 1) / alignment * alignment;
+}
+
+/**
+ * \brief Align \a value to \a alignment
+ * \param[in] value The value to align
+ * \param[in] alignment The alignment
+ * \return The value rounded down to the nearest multiple of \a alignment
+ */
+unsigned int alignDown(unsigned int value, unsigned int alignment)
+{
+	return value / alignment * alignment;
+}
+
 } /* namespace utils */
 
 } /* namespace libcamera */
diff --git a/test/utils.cpp b/test/utils.cpp
index f482e6a1d829..02054f46b00e 100644
--- a/test/utils.cpp
+++ b/test/utils.cpp
@@ -7,6 +7,7 @@
 
 #include <iostream>
 #include <map>
+#include <random>
 #include <sstream>
 #include <string>
 #include <vector>
@@ -166,6 +167,23 @@ protected:
 			return TestFail;
 		}
 
+		/* utils::alignUp() and utils::alignDown() tests. */
+		random_device random;
+		unsigned int val = random();
+		unsigned int align = random() % (val / 10);
+		unsigned int roundUp = (val + align - 1) / align;
+		unsigned int roundDown = val / align;
+
+		if (utils::alignUp(val, align) != align * roundUp) {
+			cerr << "utils::alignUp test failed" << endl;
+			return TestFail;
+		}
+
+		if (utils::alignDown(val, align) != align * roundDown) {
+			cerr << "utils::alignDown test failed" << endl;
+			return TestFail;
+		}
+
 		return TestPass;
 	}
 };
-- 
2.27.0