1//===-- TimeValue.h - Declare OS TimeValue Concept --------------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10//  This header file declares the operating system TimeValue concept.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_SUPPORT_TIMEVALUE_H
15#define LLVM_SUPPORT_TIMEVALUE_H
16
17#include "llvm/Support/DataTypes.h"
18#include <string>
19
20namespace llvm {
21namespace sys {
22  /// This class is used where a precise fixed point in time is required. The
23  /// range of TimeValue spans many hundreds of billions of years both past and
24  /// present.  The precision of TimeValue is to the nanosecond. However, the
25  /// actual precision of its values will be determined by the resolution of
26  /// the system clock. The TimeValue class is used in conjunction with several
27  /// other lib/System interfaces to specify the time at which a call should
28  /// timeout, etc.
29  /// @since 1.4
30  /// @brief Provides an abstraction for a fixed point in time.
31  class TimeValue {
32
33  /// @name Constants
34  /// @{
35  public:
36
37    /// A constant TimeValue representing the smallest time
38    /// value permissible by the class. MinTime is some point
39    /// in the distant past, about 300 billion years BCE.
40    /// @brief The smallest possible time value.
41    static const TimeValue MinTime;
42
43    /// A constant TimeValue representing the largest time
44    /// value permissible by the class. MaxTime is some point
45    /// in the distant future, about 300 billion years AD.
46    /// @brief The largest possible time value.
47    static const TimeValue MaxTime;
48
49    /// A constant TimeValue representing the base time,
50    /// or zero time of 00:00:00 (midnight) January 1st, 2000.
51    /// @brief 00:00:00 Jan 1, 2000 UTC.
52    static const TimeValue ZeroTime;
53
54    /// A constant TimeValue for the Posix base time which is
55    /// 00:00:00 (midnight) January 1st, 1970.
56    /// @brief 00:00:00 Jan 1, 1970 UTC.
57    static const TimeValue PosixZeroTime;
58
59    /// A constant TimeValue for the Win32 base time which is
60    /// 00:00:00 (midnight) January 1st, 1601.
61    /// @brief 00:00:00 Jan 1, 1601 UTC.
62    static const TimeValue Win32ZeroTime;
63
64  /// @}
65  /// @name Types
66  /// @{
67  public:
68    typedef int64_t SecondsType;    ///< Type used for representing seconds.
69    typedef int32_t NanoSecondsType;///< Type used for representing nanoseconds.
70
71    enum TimeConversions {
72      NANOSECONDS_PER_SECOND = 1000000000,  ///< One Billion
73      MICROSECONDS_PER_SECOND = 1000000,    ///< One Million
74      MILLISECONDS_PER_SECOND = 1000,       ///< One Thousand
75      NANOSECONDS_PER_MICROSECOND = 1000,   ///< One Thousand
76      NANOSECONDS_PER_MILLISECOND = 1000000,///< One Million
77      NANOSECONDS_PER_WIN32_TICK = 100      ///< Win32 tick is 10^7 Hz (10ns)
78    };
79
80  /// @}
81  /// @name Constructors
82  /// @{
83  public:
84    /// \brief Default construct a time value, initializing to ZeroTime.
85    TimeValue() : seconds_(0), nanos_(0) {}
86
87    /// Caller provides the exact value in seconds and nanoseconds. The
88    /// \p nanos argument defaults to zero for convenience.
89    /// @brief Explicit constructor
90    explicit TimeValue (SecondsType seconds, NanoSecondsType nanos = 0)
91      : seconds_( seconds ), nanos_( nanos ) { this->normalize(); }
92
93    /// Caller provides the exact value as a double in seconds with the
94    /// fractional part representing nanoseconds.
95    /// @brief Double Constructor.
96    explicit TimeValue( double new_time )
97      : seconds_( 0 ) , nanos_ ( 0 ) {
98      SecondsType integer_part = static_cast<SecondsType>( new_time );
99      seconds_ = integer_part;
100      nanos_ = static_cast<NanoSecondsType>( (new_time -
101               static_cast<double>(integer_part)) * NANOSECONDS_PER_SECOND );
102      this->normalize();
103    }
104
105    /// This is a static constructor that returns a TimeValue that represents
106    /// the current time.
107    /// @brief Creates a TimeValue with the current time (UTC).
108    static TimeValue now();
109
110  /// @}
111  /// @name Operators
112  /// @{
113  public:
114    /// Add \p that to \p this.
115    /// @returns this
116    /// @brief Incrementing assignment operator.
117    TimeValue& operator += (const TimeValue& that ) {
118      this->seconds_ += that.seconds_  ;
119      this->nanos_ += that.nanos_ ;
120      this->normalize();
121      return *this;
122    }
123
124    /// Subtract \p that from \p this.
125    /// @returns this
126    /// @brief Decrementing assignment operator.
127    TimeValue& operator -= (const TimeValue &that ) {
128      this->seconds_ -= that.seconds_ ;
129      this->nanos_ -= that.nanos_ ;
130      this->normalize();
131      return *this;
132    }
133
134    /// Determine if \p this is less than \p that.
135    /// @returns True iff *this < that.
136    /// @brief True if this < that.
137    int operator < (const TimeValue &that) const { return that > *this; }
138
139    /// Determine if \p this is greather than \p that.
140    /// @returns True iff *this > that.
141    /// @brief True if this > that.
142    int operator > (const TimeValue &that) const {
143      if ( this->seconds_ > that.seconds_ ) {
144          return 1;
145      } else if ( this->seconds_ == that.seconds_ ) {
146          if ( this->nanos_ > that.nanos_ ) return 1;
147      }
148      return 0;
149    }
150
151    /// Determine if \p this is less than or equal to \p that.
152    /// @returns True iff *this <= that.
153    /// @brief True if this <= that.
154    int operator <= (const TimeValue &that) const { return that >= *this; }
155
156    /// Determine if \p this is greater than or equal to \p that.
157    /// @returns True iff *this >= that.
158    int operator >= (const TimeValue &that) const {
159      if ( this->seconds_ > that.seconds_ ) {
160          return 1;
161      } else if ( this->seconds_ == that.seconds_ ) {
162          if ( this->nanos_ >= that.nanos_ ) return 1;
163      }
164      return 0;
165    }
166
167    /// Determines if two TimeValue objects represent the same moment in time.
168    /// @returns True iff *this == that.
169    int operator == (const TimeValue &that) const {
170      return (this->seconds_ == that.seconds_) &&
171             (this->nanos_ == that.nanos_);
172    }
173
174    /// Determines if two TimeValue objects represent times that are not the
175    /// same.
176    /// @returns True iff *this != that.
177    int operator != (const TimeValue &that) const { return !(*this == that); }
178
179    /// Adds two TimeValue objects together.
180    /// @returns The sum of the two operands as a new TimeValue
181    /// @brief Addition operator.
182    friend TimeValue operator + (const TimeValue &tv1, const TimeValue &tv2);
183
184    /// Subtracts two TimeValue objects.
185    /// @returns The difference of the two operands as a new TimeValue
186    /// @brief Subtraction operator.
187    friend TimeValue operator - (const TimeValue &tv1, const TimeValue &tv2);
188
189  /// @}
190  /// @name Accessors
191  /// @{
192  public:
193
194    /// Returns only the seconds component of the TimeValue. The nanoseconds
195    /// portion is ignored. No rounding is performed.
196    /// @brief Retrieve the seconds component
197    SecondsType seconds() const { return seconds_; }
198
199    /// Returns only the nanoseconds component of the TimeValue. The seconds
200    /// portion is ignored.
201    /// @brief Retrieve the nanoseconds component.
202    NanoSecondsType nanoseconds() const { return nanos_; }
203
204    /// Returns only the fractional portion of the TimeValue rounded down to the
205    /// nearest microsecond (divide by one thousand).
206    /// @brief Retrieve the fractional part as microseconds;
207    uint32_t microseconds() const {
208      return nanos_ / NANOSECONDS_PER_MICROSECOND;
209    }
210
211    /// Returns only the fractional portion of the TimeValue rounded down to the
212    /// nearest millisecond (divide by one million).
213    /// @brief Retrieve the fractional part as milliseconds;
214    uint32_t milliseconds() const {
215      return nanos_ / NANOSECONDS_PER_MILLISECOND;
216    }
217
218    /// Returns the TimeValue as a number of microseconds. Note that the value
219    /// returned can overflow because the range of a uint64_t is smaller than
220    /// the range of a TimeValue. Nevertheless, this is useful on some operating
221    /// systems and is therefore provided.
222    /// @brief Convert to a number of microseconds (can overflow)
223    uint64_t usec() const {
224      return seconds_ * MICROSECONDS_PER_SECOND +
225             ( nanos_ / NANOSECONDS_PER_MICROSECOND );
226    }
227
228    /// Returns the TimeValue as a number of milliseconds. Note that the value
229    /// returned can overflow because the range of a uint64_t is smaller than
230    /// the range of a TimeValue. Nevertheless, this is useful on some operating
231    /// systems and is therefore provided.
232    /// @brief Convert to a number of milliseconds (can overflow)
233    uint64_t msec() const {
234      return seconds_ * MILLISECONDS_PER_SECOND +
235             ( nanos_ / NANOSECONDS_PER_MILLISECOND );
236    }
237
238    /// Converts the TimeValue into the corresponding number of seconds
239    /// since the epoch (00:00:00 Jan 1,1970).
240    uint64_t toEpochTime() const {
241      return seconds_ - PosixZeroTimeSeconds;
242    }
243
244    /// Converts the TimeValue into the corresponding number of "ticks" for
245    /// Win32 platforms, correcting for the difference in Win32 zero time.
246    /// @brief Convert to Win32's FILETIME
247    /// (100ns intervals since 00:00:00 Jan 1, 1601 UTC)
248    uint64_t toWin32Time() const {
249      uint64_t result = (uint64_t)10000000 * (seconds_ - Win32ZeroTimeSeconds);
250      result += nanos_ / NANOSECONDS_PER_WIN32_TICK;
251      return result;
252    }
253
254    /// Provides the seconds and nanoseconds as results in its arguments after
255    /// correction for the Posix zero time.
256    /// @brief Convert to timespec time (ala POSIX.1b)
257    void getTimespecTime( uint64_t& seconds, uint32_t& nanos ) const {
258      seconds = seconds_ - PosixZeroTimeSeconds;
259      nanos = nanos_;
260    }
261
262    /// Provides conversion of the TimeValue into a readable time & date.
263    /// @returns std::string containing the readable time value
264    /// @brief Convert time to a string.
265    std::string str() const;
266
267  /// @}
268  /// @name Mutators
269  /// @{
270  public:
271    /// The seconds component of the TimeValue is set to \p sec without
272    /// modifying the nanoseconds part.  This is useful for whole second
273    /// arithmetic.
274    /// @brief Set the seconds component.
275    void seconds (SecondsType sec ) {
276      this->seconds_ = sec;
277      this->normalize();
278    }
279
280    /// The nanoseconds component of the TimeValue is set to \p nanos without
281    /// modifying the seconds part. This is useful for basic computations
282    /// involving just the nanoseconds portion. Note that the TimeValue will be
283    /// normalized after this call so that the fractional (nanoseconds) portion
284    /// will have the smallest equivalent value.
285    /// @brief Set the nanoseconds component using a number of nanoseconds.
286    void nanoseconds ( NanoSecondsType nanos ) {
287      this->nanos_ = nanos;
288      this->normalize();
289    }
290
291    /// The seconds component remains unchanged.
292    /// @brief Set the nanoseconds component using a number of microseconds.
293    void microseconds ( int32_t micros ) {
294      this->nanos_ = micros * NANOSECONDS_PER_MICROSECOND;
295      this->normalize();
296    }
297
298    /// The seconds component remains unchanged.
299    /// @brief Set the nanoseconds component using a number of milliseconds.
300    void milliseconds ( int32_t millis ) {
301      this->nanos_ = millis * NANOSECONDS_PER_MILLISECOND;
302      this->normalize();
303    }
304
305    /// @brief Converts from microsecond format to TimeValue format
306    void usec( int64_t microseconds ) {
307      this->seconds_ = microseconds / MICROSECONDS_PER_SECOND;
308      this->nanos_ = NanoSecondsType(microseconds % MICROSECONDS_PER_SECOND) *
309        NANOSECONDS_PER_MICROSECOND;
310      this->normalize();
311    }
312
313    /// @brief Converts from millisecond format to TimeValue format
314    void msec( int64_t milliseconds ) {
315      this->seconds_ = milliseconds / MILLISECONDS_PER_SECOND;
316      this->nanos_ = NanoSecondsType(milliseconds % MILLISECONDS_PER_SECOND) *
317        NANOSECONDS_PER_MILLISECOND;
318      this->normalize();
319    }
320
321    /// Converts the \p seconds argument from PosixTime to the corresponding
322    /// TimeValue and assigns that value to \p this.
323    /// @brief Convert seconds form PosixTime to TimeValue
324    void fromEpochTime( SecondsType seconds ) {
325      seconds_ = seconds + PosixZeroTimeSeconds;
326      nanos_ = 0;
327      this->normalize();
328    }
329
330    /// Converts the \p win32Time argument from Windows FILETIME to the
331    /// corresponding TimeValue and assigns that value to \p this.
332    /// @brief Convert seconds form Windows FILETIME to TimeValue
333    void fromWin32Time( uint64_t win32Time ) {
334      this->seconds_ = win32Time / 10000000 + Win32ZeroTimeSeconds;
335      this->nanos_ = NanoSecondsType(win32Time  % 10000000) * 100;
336    }
337
338  /// @}
339  /// @name Implementation
340  /// @{
341  private:
342    /// This causes the values to be represented so that the fractional
343    /// part is minimized, possibly incrementing the seconds part.
344    /// @brief Normalize to canonical form.
345    void normalize();
346
347  /// @}
348  /// @name Data
349  /// @{
350  private:
351    /// Store the values as a <timeval>.
352    SecondsType      seconds_;///< Stores the seconds part of the TimeVal
353    NanoSecondsType  nanos_;  ///< Stores the nanoseconds part of the TimeVal
354
355    static const SecondsType PosixZeroTimeSeconds;
356    static const SecondsType Win32ZeroTimeSeconds;
357  /// @}
358
359  };
360
361inline TimeValue operator + (const TimeValue &tv1, const TimeValue &tv2) {
362  TimeValue sum (tv1.seconds_ + tv2.seconds_, tv1.nanos_ + tv2.nanos_);
363  sum.normalize ();
364  return sum;
365}
366
367inline TimeValue operator - (const TimeValue &tv1, const TimeValue &tv2) {
368  TimeValue difference (tv1.seconds_ - tv2.seconds_, tv1.nanos_ - tv2.nanos_ );
369  difference.normalize ();
370  return difference;
371}
372
373}
374}
375
376#endif
377