// bbldc_calendardaycountutil.h                                       -*-C++-*-
#ifndef INCLUDED_BBLDC_CALENDARDAYCOUNTUTIL
#define INCLUDED_BBLDC_CALENDARDAYCOUNTUTIL

#include <bsls_ident.h>
BSLS_IDENT("$Id: $")

//@PURPOSE: Support for day-count calculations of 'enum'-specified conventions.
//
//@CLASSES:
//  bbldc::CalendarDayCountUtil: 'enum'-specified day-count calculations
//
//@SEE_ALSO: bbldc_daycountconvention, bbldc_calendarbus252
//
//@DESCRIPTION: This component provides a 'struct',
// 'bbldc::CalendarDayCountUtil', that defines a suite of date-related
// functions used to compute the day count and the year fraction between two
// dates as prescribed by an enumerated day-count convention.  Specifically,
// the 'daysDiff' and 'yearsDiff' methods defined in
// 'bbldc::CalendarDayCountUtil' take a trailing 'DayCountConvention::Enum'
// argument indicating which particular day-count convention to apply.
//
///Usage
///-----
// This section illustrates intended use of this component.
//
///Example 1: Computing Day Count and Year Fraction
/// - - - - - - - - - - - - - - - - - - - - - - - -
// The following snippets of code illustrate how to use
// 'bbldc::CalendarDayCountUtil' methods.  First, create two 'bdlt::Date'
// variables, 'd1' and 'd2':
//..
//  const bdlt::Date d1(2003, 10, 19);
//  const bdlt::Date d2(2003, 12, 31);
//..
// Then, create a 'calendar' with a valid range spanning 2003 and typical
// weekend days:
//..
//  bdlt::Calendar calendar;
//  calendar.setValidRange(bdlt::Date(2003, 1, 1), bdlt::Date(2003, 12, 31));
//  calendar.addWeekendDay(bdlt::DayOfWeek::e_SUN);
//  calendar.addWeekendDay(bdlt::DayOfWeek::e_SAT);
//..
// Now, compute the day count between 'd1' and 'd2' according to the BUS-252
// day-count convention:
//..
//  const int daysDiff = bbldc::CalendarDayCountUtil::daysDiff(
//                              d1,
//                              d2,
//                              calendar,
//                              bbldc::DayCountConvention::e_CALENDAR_BUS_252);
//  assert(52 == daysDiff);
//..
// Finally, compute the year fraction between the two dates according to the
// BUS-252 day-count convention:
//..
//  const double yearsDiff = bbldc::CalendarDayCountUtil::yearsDiff(
//                              d1,
//                              d2,
//                              calendar,
//                              bbldc::DayCountConvention::e_CALENDAR_BUS_252);
//  // Need fuzzy comparison since 'yearsDiff' is a 'double'.
//  assert(0.2063 < yearsDiff && 0.2064 > yearsDiff);
//..

#include <bblscm_version.h>

#include <bbldc_daycountconvention.h>

#include <bdlt_calendar.h>
#include <bdlt_date.h>

namespace BloombergLP {
namespace bbldc {

                       // ===========================
                       // struct CalendarDayCountUtil
                       // ===========================

struct CalendarDayCountUtil {
    // This 'struct' provides a namespace for a suite of pure functions that
    // compute values based on dates according to enumerated day-count
    // conventions.

    // CLASS METHODS
    static int daysDiff(const bdlt::Date&        beginDate,
                        const bdlt::Date&        endDate,
                        const bdlt::Calendar&    calendar,
                        DayCountConvention::Enum convention);
        // Return the (signed) number of days between the specified 'beginDate'
        // and 'endDate' according to the specified day-count 'convention' with
        // the specified 'calendar' providing the definition of business days.
        // If 'beginDate <= endDate' then the result is non-negative.  The
        // behavior is undefined unless 'isSupported(convention)',
        // 'calendar.isInRange(beginDate)', and 'calendar.isInRange(endDate)'.
        // Note that reversing the order of 'beginDate' and 'endDate' negates
        // the result and that the result is 0 when 'beginDate == endDate'.

    static bool isSupported(DayCountConvention::Enum convention);
        // Return 'true' if the specified 'convention' is valid for use in
        // 'daysDiff' and 'yearsDiff', and 'false' otherwise.

    static double yearsDiff(const bdlt::Date&        beginDate,
                            const bdlt::Date&        endDate,
                            const bdlt::Calendar&    calendar,
                            DayCountConvention::Enum convention);
        // Return the (signed fractional) number of years between the specified
        // 'beginDate' and 'endDate' according to the specified day-count
        // 'convention' with the specified 'calendar' providing the definition
        // of business days.  If 'beginDate <= endDate' then the result is
        // non-negative.  The behavior is undefined unless
        // 'isSupported(convention)', 'calendar.isInRange(beginDate)', and
        // 'calendar.isInRange(endDate)'.  Note that reversing the order of
        // 'beginDate' and 'endDate' negates the result; specifically,
        // '|yearsDiff(b, e, cal, c) + yearsDiff(e, b, cal, c)| <= 1.0e-15' for
        // all calendars 'cal', valid dates 'b' and 'e', and day-count
        // conventions 'c'.
};

}  // close package namespace
}  // close enterprise namespace

#endif

// ----------------------------------------------------------------------------
// Copyright 2015 Bloomberg Finance L.P.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ----------------------------- END-OF-FILE ----------------------------------