gecko-dev/dom/smil/SMILTimeValue.h

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4.2 KiB
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/* -*- 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 mozilla_SMILTimeValue_h
#define mozilla_SMILTimeValue_h
#include "mozilla/SMILTypes.h"
#include "nsDebug.h"
namespace mozilla {
/*----------------------------------------------------------------------
* SMILTimeValue class
*
* A tri-state time value.
*
* First a quick overview of the SMIL time data types:
*
* SMILTime -- a timestamp in milliseconds.
* SMILTimeValue -- (this class) a timestamp that can take the additional
* states 'indefinite' and 'unresolved'
* SMILInstanceTime -- an SMILTimeValue used for constructing intervals. It
* contains additional fields to govern reset behavior
* and track timing dependencies (e.g. syncbase timing).
* SMILInterval -- a pair of SMILInstanceTimes that defines a begin and
* an end time for animation.
* SMILTimeValueSpec -- 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 SMILTimedElement and its
* SMILInstanceTimes 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 | SMILTimeValue | true | false | true
* -----------+---------------+------------+--------------+------------
* Indefinite | -- | false | true | true
* -----------+---------------+------------+--------------+------------
* Unresolved | -- | false | false | false
*
*/
class SMILTimeValue {
public:
// Creates an unresolved time value
SMILTimeValue()
: mMilliseconds(kUnresolvedMillis), mState(STATE_UNRESOLVED) {}
// Creates a resolved time value
explicit SMILTimeValue(SMILTime aMillis)
: mMilliseconds(aMillis), mState(STATE_DEFINITE) {}
// Named constructor to create an indefinite time value
static SMILTimeValue Indefinite() {
SMILTimeValue 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; }
SMILTime GetMillis() const {
MOZ_ASSERT(mState == STATE_DEFINITE,
"GetMillis() called for unresolved or indefinite time");
return mState == STATE_DEFINITE ? mMilliseconds : kUnresolvedMillis;
}
void SetMillis(SMILTime aMillis) {
mState = STATE_DEFINITE;
mMilliseconds = aMillis;
}
int8_t CompareTo(const SMILTimeValue& aOther) const;
bool operator==(const SMILTimeValue& aOther) const {
return CompareTo(aOther) == 0;
}
bool operator!=(const SMILTimeValue& aOther) const {
return CompareTo(aOther) != 0;
}
bool operator<(const SMILTimeValue& aOther) const {
return CompareTo(aOther) < 0;
}
bool operator>(const SMILTimeValue& aOther) const {
return CompareTo(aOther) > 0;
}
bool operator<=(const SMILTimeValue& aOther) const {
return CompareTo(aOther) <= 0;
}
bool operator>=(const SMILTimeValue& aOther) const {
return CompareTo(aOther) >= 0;
}
private:
static const SMILTime kUnresolvedMillis;
SMILTime mMilliseconds;
enum { STATE_DEFINITE, STATE_INDEFINITE, STATE_UNRESOLVED } mState;
};
} // namespace mozilla
#endif // mozilla_SMILTimeValue_h