function [uniqueStrings, modified] = makeUniqueStrings(inStr, excludes, maxStringLength)

%MATLAB.LANG.MAKEUNIQUESTRINGS Constructs unique strings from input strings

%   U = MATLAB.LANG.MAKEUNIQUESTRINGS(S) constructs unique elements,

%   U, from S by appending an underscore and a number to duplicates. S

%   is a character vector (i.e. a 1xN character array or ''), a cell array

%   of character vectors, or a string array.

%

%   U = MATLAB.LANG.MAKEUNIQUESTRINGS(S, EXCLUDED) makes the elements

%   in S unique among themselves and unique with respect to EXCLUDED.

%   MAKEUNIQUESTRINGS does not check EXCLUDED for uniqueness.

%

%   U = MATLAB.LANG.MAKEUNIQUESTRINGS(S, WHICHSTRINGS) makes the elements

%   in S(WHICHSTRINGS) unique among themselves and with respect to the

%   remaining elements. WHICHSTRINGS is a logical vector or a vector of

%   indices. MAKEUNIQUESTRINGS does not check the remaining elements for

%   uniqueness, and returns them unmodified in U. Use this syntax when you

%   have a cell or string array and need to check that only some elements

%   of the array are unique.

%

%   U = MATLAB.LANG.MAKEUNIQUESTRINGS(S, ___, MAXSTRINGLENGTH)

%   specifies the maximum strlength, MAXSTRINGLENGTH, of the elements in U.

%   If MAKEUNIQUESTRINGS cannot make elements in S unique without exceeding

%   MAXSTRINGLENGTH, it throws an error.

%

%   [U, MODIFIED] = MATLAB.LANG.MAKEUNIQUESTRINGS(S, ___) also returns a

%   logical array the same size as S to denote modified elements.

%

%   Examples

%   --------

%   Make unique character vectors with respect to workspace variable names

%

%       var3 = 0;

%       varNames = MATLAB.LANG.MAKEUNIQUESTRINGS({'var' 'var2' 'var' 'var3'}, who)

%

%   returns the cell array {'var' 'var2' 'var_1' 'var3_1'}

%

%   Make unique character vectors by checking only some elements of the array

%

%       names = {'Peter' 'Jeremy' 'Campion' 'Nick' 'Nick'};

%       names = MATLAB.LANG.MAKEUNIQUESTRINGS(names, [2 4])

%

%   returns the cell array {'Peter' 'Jeremy' 'Campion' 'Nick_1' 'Nick'}

%

%   See also MATLAB.LANG.MAKEVALIDNAME, NAMELENGTHMAX, WHO.

%   Copyright 2013-2019 The MathWorks, Inc.

% Validate number of inputs.

narginchk(1,3); 

% Validate input string.

inputIsChar = false; 

inputIsCell = false; 

if matlab.internal.datatypes.isCharString(inStr) 

    inputIsChar = true;

elseif matlab.internal.datatypes.isCharStrings(inStr, true) 

    inputIsCell = true; 

elseif ~isstring(inStr)

    error(message('MATLAB:makeUniqueStrings:InvalidInputStrings'))

elseif any(ismissing(inStr(:)))

    error(message('MATLAB:makeUniqueStrings:MissingNames', ...

                  getString(message('MATLAB:string:MissingDisplayText'))));

end 

if isempty(inStr) 

    uniqueStrings = inStr;

    if inputIsChar

        modified = false;

    else

        modified = false(size(inStr));

    end

    return;

end 

inStr = string(inStr); 

% Set/validate EXCLSTRORELEMTOCHK and MAXSTRINGLENGTH.

[~, maxArraySize] = computer; 

if nargin < 3 

    maxStringLength = maxArraySize;

else 

    maxStringLength = validateMaxStringLength(maxStringLength, maxArraySize); 

end 

if nargin < 2 

    exclStrOrElemToChk = string({});

else 

    exclStrOrElemToChk = validateExclStrOrElemToChk(excludes, inStr); 

end 

% Process differently for 2nd option as checkElements or stringsToProtect.

if isnumeric(exclStrOrElemToChk) || islogical(exclStrOrElemToChk) % checkElements 

    % Construct stringsToCheck from STRINGS that need to be made unique.

    stringsToCheck = inStr(exclStrOrElemToChk);

    % Truncate only the stringsToCheck.

    if nargout > 1

        truncated = false(size(inStr));

    end

    if maxStringLength < maxArraySize

        [stringsToCheck, truncated(exclStrOrElemToChk)] = truncateString(stringsToCheck, maxStringLength);

    end

    % Construct stringsToProtect from STRINGS that should not be modified.

    if islogical(exclStrOrElemToChk)

        stringsToProtect = inStr(~exclStrOrElemToChk);

    else % exclStrOrElemToChk is indices

        stringsToProtect = inStr(setdiff(1:numel(inStr),exclStrOrElemToChk));

    end

    % Make stringsToCheck unique against itself and stringsToProtect.

    [stringsChecked, modifiedInStringsChecked] = ...

        makeUnique(stringsToCheck, stringsToProtect, maxStringLength);

    % Combine the protected subset of strings with the checked subset.

    uniqueStrings = inStr;

    uniqueStrings(exclStrOrElemToChk) = stringsChecked;

    % Compute the positions of modified strings in the now completed set.

    if nargout > 1

        uniquified = false(size(inStr));

        uniquified(exclStrOrElemToChk) = modifiedInStringsChecked;

    end

else % stringsToProtect 

    if maxStringLength < maxArraySize 

        [inStr, truncated] = truncateString(inStr, maxStringLength); 

    elseif nargout > 1

        truncated = false(size(inStr));

    end     

    [uniqueStrings, uniquified] = ... 

        makeUnique(inStr, exclStrOrElemToChk, maxStringLength); 

end 

if maxStringLength == 0 && inputIsChar 

    uniqueStrings = char(zeros(1, 0));

    modified = true;

    return;

end 

if inputIsChar 

    uniqueStrings = char(uniqueStrings);

elseif inputIsCell 

    uniqueStrings = cellstr(uniqueStrings); 

end 

if nargout > 1 

    modified = truncated | uniquified; 

end 

end