initial commit of Gregorian/IFC date conversion tools and unit tests

IFCmonths.m

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+function [nMonths, Days, leaped, yeared] = IFCmonths(Days, Year)
+arguments (Input)
+    Days    (:, 1) uint16
+    Year    (:, 1) uint16
+end
+arguments (Output)
+    nMonths (:, 1) uint8
+    Days    (:, 1) uint8
+    leaped  (:, 1) logical
+    yeared  (:, 1) logical
+end
+
+% intialize output to first month
+nMonths = ones(size(Days));
+
+% initialize output saying a leap day happened to false
+leaped = false(size(Days));
+
+% initialize output saying a year day happened to false
+yeared = false(size(Days));
+
+% check if it's a leap year
+leap = isLeap(Year);
+
+% while more days than 1 month, add months to nMonths
+excess = Days > 28;
+while any(excess)
+    % Subtract 28 days and add one month
+    Days(excess) = Days(excess) - 28;
+    nMonths(excess) = nMonths(excess) + 1;
+
+    % Find dates which are reaching the leap day (if it exists)
+    leaping = (leap & nMonths == 7);
+    % subtract leap day before proceeding to add another month
+    Days(leaping) = Days(leaping) - 1;
+    % Set leap day output to true
+    leaped(leaping) = true;
+    % Set the month to 14 (no month) if there are no days left
+    % meaning the last day is the leap day 
+    % (which is not in any month)
+    noneLeft = ~Days;
+    nMonths(noneLeft) = 14;
+    % continue subtracting days and adding months as needed
+
+    % find excess days remaining for next iteration
+    excess = Days > 28;
+end
+
+% check for if a year day occured
+yearing = (nMonths == 14 & Days == 1);
+yeared(yearing) = true; % Year day achieved, set flag
+Days(yearing) = 0; % decrement Days since year day was taken
+end