gecko-dev/dom/smil/nsSMILTimeValue.h

136 lines
4.2 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef NS_SMILTIMEVALUE_H_
#define NS_SMILTIMEVALUE_H_
#include "nsSMILTypes.h"
#include "nsDebug.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'
* nsSMILInstanceTime -- an nsSMILTimeValue used for constructing intervals. It
* contains additional fields to govern reset behavior
* and track timing dependencies (e.g. syncbase timing).
* nsSMILInterval -- a pair of nsSMILInstanceTimes that defines a begin and
* an end time for animation.
* nsSMILTimeValueSpec -- a component of a begin or end attribute, such as the
* '5s' or 'a.end+2m' in begin="5s; a.end+2m". Acts as
* a broker between an nsSMILTimedElement and its
* nsSMILInstanceTimes by generating new instance times
* and handling changes to existing times.
*
* Objects of this class may be in one of three states:
*
* 1) The time is resolved and has a definite millisecond value
* 2) The time is resolved and indefinite
* 3) The time is unresolved
*
* In summary:
*
* State | GetMillis | IsDefinite | IsIndefinite | IsResolved
* -----------+-----------------+------------+--------------+------------
* Definite | nsSMILTimeValue | true | false | true
* -----------+-----------------+------------+--------------+------------
* Indefinite | -- | false | true | true
* -----------+-----------------+------------+--------------+------------
* Unresolved | -- | false | false | false
*
*/
class nsSMILTimeValue
{
public:
// Creates an unresolved time value
nsSMILTimeValue()
: mMilliseconds(kUnresolvedMillis),
mState(STATE_UNRESOLVED)
{ }
// Creates a resolved time value
explicit nsSMILTimeValue(nsSMILTime aMillis)
: mMilliseconds(aMillis),
mState(STATE_DEFINITE)
{ }
// Named constructor to create an indefinite time value
static nsSMILTimeValue Indefinite()
{
nsSMILTimeValue value;
value.SetIndefinite();
return value;
}
bool IsIndefinite() const { return mState == STATE_INDEFINITE; }
void SetIndefinite()
{
mState = STATE_INDEFINITE;
mMilliseconds = kUnresolvedMillis;
}
bool IsResolved() const { return mState != STATE_UNRESOLVED; }
void SetUnresolved()
{
mState = STATE_UNRESOLVED;
mMilliseconds = kUnresolvedMillis;
}
bool IsDefinite() const { return mState == STATE_DEFINITE; }
nsSMILTime GetMillis() const
{
MOZ_ASSERT(mState == STATE_DEFINITE,
"GetMillis() called for unresolved or indefinite time");
return mState == STATE_DEFINITE ? mMilliseconds : kUnresolvedMillis;
}
void SetMillis(nsSMILTime aMillis)
{
mState = STATE_DEFINITE;
mMilliseconds = aMillis;
}
int8_t CompareTo(const nsSMILTimeValue& aOther) const;
bool operator==(const nsSMILTimeValue& aOther) const
{ return CompareTo(aOther) == 0; }
bool operator!=(const nsSMILTimeValue& aOther) const
{ return CompareTo(aOther) != 0; }
bool operator<(const nsSMILTimeValue& aOther) const
{ return CompareTo(aOther) < 0; }
bool operator>(const nsSMILTimeValue& aOther) const
{ return CompareTo(aOther) > 0; }
bool operator<=(const nsSMILTimeValue& aOther) const
{ return CompareTo(aOther) <= 0; }
bool operator>=(const nsSMILTimeValue& aOther) const
{ return CompareTo(aOther) >= 0; }
private:
static const nsSMILTime kUnresolvedMillis;
nsSMILTime mMilliseconds;
enum {
STATE_DEFINITE,
STATE_INDEFINITE,
STATE_UNRESOLVED
} mState;
};
#endif // NS_SMILTIMEVALUE_H_