FindRightMostHighBit: Add it

AllenInstitute · Oct 19, 2023 · e0fcb1c · e0fcb1c
1 parent 3126726
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diff --git a/Packages/MIES/MIES_Utilities.ipf b/Packages/MIES/MIES_Utilities.ipf
@@ -6710,3 +6710,25 @@ threadsafe Function/S UpperCaseFirstChar(string str)
 
 	return UpperStr(str[0]) + str[1, len - 1]
 End
+
+/// @brief Find the right most high bit
+///
+/// @param value integer value in the range [0, 2^64]
+///
+/// @return right most high bit or NaN in case nothing could be found
+threadsafe Function FindRightMostHighBit(uint64 value)
+
+	variable i
+	uint64 bit
+
+	for(i = 0; i < 64; i += 1)
+
+		bit = value & (1 << i)
+
+		if(bit)
+			return i
+		endif
+	endfor
+
+	return NaN
+End
diff --git a/Packages/tests/Basic/UTF_Utils.ipf b/Packages/tests/Basic/UTF_Utils.ipf
@@ -7253,3 +7253,14 @@ Function TestSearchWordInString()
 	CHECK_EQUAL_STR(prefix, "ab#")
 	CHECK_EQUAL_STR(suffix, "?efgh")
 End
+
+static Function TestFindRightMostHighBit()
+
+	Make/FREE/N=(64) result = FindRightMostHighBit(1 << p) == p
+	CHECK_EQUAL_VAR(sum(result), 64)
+
+	CHECK_EQUAL_VAR(FindRightMostHighBit(0), NaN)
+
+	CHECK_EQUAL_VAR(FindRightMostHighBit(3), 0)
+	CHECK_EQUAL_VAR(FindRightMostHighBit(18), 1)
+End