117 lines
2.8 KiB
C
117 lines
2.8 KiB
C
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//------------------------------------------------------------------------------
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// File: RefTime.h
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//
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// Desc: DirectShow base classes - defines CRefTime, a class that manages
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// reference times.
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//
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// Copyright (c) 1992-2001 Microsoft Corporation. All rights reserved.
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//------------------------------------------------------------------------------
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//
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// CRefTime
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//
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// Manage reference times.
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// Shares same data layout as REFERENCE_TIME, but adds some (nonvirtual)
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// functions providing simple comparison, conversion and arithmetic.
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//
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// A reference time (at the moment) is a unit of seconds represented in
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// 100ns units as is used in the Win32 FILETIME structure. BUT the time
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// a REFERENCE_TIME represents is NOT the time elapsed since 1/1/1601 it
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// will either be stream time or reference time depending upon context
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//
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// This class provides simple arithmetic operations on reference times
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//
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// keep non-virtual otherwise the data layout will not be the same as
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// REFERENCE_TIME
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// -----
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// note that you are safe to cast a CRefTime* to a REFERENCE_TIME*, but
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// you will need to do so explicitly
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// -----
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#ifndef __REFTIME__
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#define __REFTIME__
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const LONGLONG MILLISECONDS = (1000); // 10 ^ 3
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const LONGLONG NANOSECONDS = (1000000000); // 10 ^ 9
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const LONGLONG UNITS = (NANOSECONDS / 100); // 10 ^ 7
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/* Unfortunately an inline function here generates a call to __allmul
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- even for constants!
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*/
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#define MILLISECONDS_TO_100NS_UNITS(lMs) \
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Int32x32To64((lMs), (UNITS / MILLISECONDS))
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class CRefTime
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{
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public:
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// *MUST* be the only data member so that this class is exactly
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// equivalent to a REFERENCE_TIME.
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// Also, must be *no virtual functions*
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REFERENCE_TIME m_time;
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inline CRefTime()
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{
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// default to 0 time
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m_time = 0;
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};
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inline CRefTime(LONG msecs)
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{
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m_time = MILLISECONDS_TO_100NS_UNITS(msecs);
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};
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inline CRefTime(REFERENCE_TIME rt)
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{
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m_time = rt;
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};
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inline operator REFERENCE_TIME() const
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{
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return m_time;
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};
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inline CRefTime& operator=(const CRefTime& rt)
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{
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m_time = rt.m_time;
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return *this;
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};
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inline CRefTime& operator=(const LONGLONG ll)
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{
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m_time = ll;
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return *this;
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};
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inline CRefTime& operator+=(const CRefTime& rt)
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{
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return (*this = *this + rt);
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};
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inline CRefTime& operator-=(const CRefTime& rt)
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{
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return (*this = *this - rt);
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};
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inline LONG Millisecs(void)
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{
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return (LONG)(m_time / (UNITS / MILLISECONDS));
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};
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inline LONGLONG GetUnits(void)
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{
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return m_time;
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};
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};
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const LONGLONG TimeZero = 0;
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#endif /* __REFTIME__ */
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