gecko/content/smil/nsSMILTimeValue.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (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.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is the Mozilla SMIL module.
*
* The Initial Developer of the Original Code is Brian Birtles.
* Portions created by the Initial Developer are Copyright (C) 2005
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Brian Birtles <birtles@gmail.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#ifndef NS_SMILTIMEVALUE_H_
#define NS_SMILTIMEVALUE_H_
#include "prtypes.h"
#include "prlong.h"
#include "nsSMILTypes.h"
/*----------------------------------------------------------------------
* nsSMILTimeValue class
*
* A tri-state time value.
*
* First a quick overview of the SMIL time data types:
*
* nsSMILTime -- a timestamp in milliseconds.
* nsSMILTimeValue -- (this class) a timestamp that can take the additional
* states 'indefinite' and 'unresolved'
* nsSMILInterval -- a pair of nsSMILTimeValues that defines a begin and an
* end point.
* nsSMILInstanceTime -- an nsSMILTimeValue used for constructing intervals. It
* contains additional fields to govern reset behavior.
* It also forms an anchor for establishing syncbase
* relationships.
* nsSMILTimeValueSpec -- a component of a begin or end attribute, such as the
* '5s' or 'a.end+2m' in begin="5s; a.end+2m". These
* objects produce nsSMILInstanceTimes and are also used
* in managing dependent relationships between
* animations.
*
* Objects of this class may be in one of three states:
*
* 1) The time is resolved and has a millisecond value
* 2) The time is indefinite
* 3) The time in unresolved
*
* There is considerable chance for confusion with regards to the indefinite
* state. Is it resolved? We adopt the convention that it is NOT resolved (but
* nor is it unresolved). This simplifies implementation as you can then write:
*
* if (time.IsResolved())
* x = time.GetMillis()
*
* instead of:
*
* if (time.IsResolved() && !time.IsIndefinite())
* x = time.GetMillis()
*
* Testing if a time is unresolved becomes more complicated but this is tested
* much less often.
*
* In summary:
*
* State | GetMillis | IsResolved | IsIndefinite
* --------------+--------------------+--------------------+-------------------
* Resolved | The millisecond | PR_TRUE | PR_FALSE
* | time | |
* --------------+--------------------+--------------------+-------------------
* Indefinite | LL_MAXINT | PR_FALSE | PR_TRUE
* --------------+--------------------+--------------------+-------------------
* Unresolved | LL_MAXINT | PR_FALSE | PR_FALSE
*
*/
class nsSMILTimeValue
{
public:
// Creates an unresolved time value
nsSMILTimeValue();
PRBool IsIndefinite() const { return mState == STATE_INDEFINITE; }
void SetIndefinite();
PRBool IsResolved() const { return mState == STATE_RESOLVED; }
void SetUnresolved();
nsSMILTime GetMillis() const;
void SetMillis(nsSMILTime aMillis);
PRInt8 CompareTo(const nsSMILTimeValue& aOther) const;
private:
PRInt8 Cmp(PRInt64 aA, PRInt64 aB) const;
static nsSMILTime kUnresolvedSeconds;
nsSMILTime mMilliseconds;
enum {
STATE_RESOLVED,
STATE_INDEFINITE,
STATE_UNRESOLVED
} mState;
};
#endif // NS_SMILTIMEVALUE_H_