getNaturalTextComparison function

int getNaturalTextComparison(String firstText, String secondText)

Implementation

int getNaturalTextComparison(
    String firstText,
    String secondText
    )
{
    var firstCharacterCount = firstText.length;
    var secondCharacterCount = secondText.length;
    var firstCharacterIndex = 0;
    var secondCharacterIndex = 0;

    while ( firstCharacterIndex < firstCharacterCount
            && secondCharacterIndex < secondCharacterCount )
    {
        var firstCharacter = firstText[ firstCharacterIndex ];
        var secondCharacter = secondText[ secondCharacterIndex ];

        if ( firstCharacter == secondCharacter )
        {
            ++firstCharacterIndex;
            ++secondCharacterIndex;
        }
        else
        {
            var firstCodeUnit = firstCharacter.codeUnitAt( 0 );
            var secondCodeUnit = secondCharacter.codeUnitAt( 0 );

            if ( firstCodeUnit >= 48
                 && firstCodeUnit <= 57
                 && secondCodeUnit >= 48
                 && secondCodeUnit <= 57 )
            {
                var firstNumberText = '';
                var secondNumberText = '';

                while ( firstCharacterIndex < firstCharacterCount
                        && firstText[ firstCharacterIndex ].codeUnitAt( 0 ) >= 48
                        && firstText[ firstCharacterIndex ].codeUnitAt( 0 ) <= 57 )
                {
                    firstNumberText += firstText[ firstCharacterIndex ];

                    ++firstCharacterIndex;
                }

                while ( secondCharacterIndex < secondCharacterCount
                        && secondText[ secondCharacterIndex ].codeUnitAt( 0 ) >= 48
                        && secondText[ secondCharacterIndex ].codeUnitAt( 0 ) <= 57 )
                {
                    secondNumberText += secondText[ secondCharacterIndex ];

                    ++secondCharacterIndex;
                }

                return int.parse( firstNumberText ) - int.parse( secondNumberText );
            }
            else
            {
                return firstCharacter.compareTo( secondCharacter );
            }
        }
    }

    return firstCharacterCount - secondCharacterCount;
}