LLVM API Documentation
00001 //===-- TimeValue.h - Declare OS TimeValue Concept --------------*- C++ -*-===// 00002 // 00003 // The LLVM Compiler Infrastructure 00004 // 00005 // This file was developed by Reid Spencer and is distributed under the 00006 // University of Illinois Open Source License. See LICENSE.TXT for details. 00007 // 00008 //===----------------------------------------------------------------------===// 00009 // 00010 // This header file declares the operating system TimeValue concept. 00011 // 00012 //===----------------------------------------------------------------------===// 00013 00014 #include "llvm/Support/DataTypes.h" 00015 #include <string> 00016 00017 #ifndef LLVM_SYSTEM_TIMEVALUE_H 00018 #define LLVM_SYSTEM_TIMEVALUE_H 00019 00020 namespace llvm { 00021 namespace sys { 00022 /// This class is used where a precise fixed point in time is required. The 00023 /// range of TimeValue spans many hundreds of billions of years both past and 00024 /// present. The precision of TimeValue is to the nanosecond. However, the 00025 /// actual precision of its values will be determined by the resolution of 00026 /// the system clock. The TimeValue class is used in conjunction with several 00027 /// other lib/System interfaces to specify the time at which a call should 00028 /// timeout, etc. 00029 /// @since 1.4 00030 /// @brief Provides an abstraction for a fixed point in time. 00031 class TimeValue { 00032 00033 /// @name Constants 00034 /// @{ 00035 public: 00036 00037 /// A constant TimeValue representing the smallest time 00038 /// value permissable by the class. MinTime is some point 00039 /// in the distant past, about 300 billion years BCE. 00040 /// @brief The smallest possible time value. 00041 static const TimeValue MinTime; 00042 00043 /// A constant TimeValue representing the largest time 00044 /// value permissable by the class. MaxTime is some point 00045 /// in the distant future, about 300 billion years AD. 00046 /// @brief The largest possible time value. 00047 static const TimeValue MaxTime; 00048 00049 /// A constant TimeValue representing the base time, 00050 /// or zero time of 00:00:00 (midnight) January 1st, 2000. 00051 /// @brief 00:00:00 Jan 1, 2000 UTC. 00052 static const TimeValue ZeroTime; 00053 00054 /// A constant TimeValue for the Posix base time which is 00055 /// 00:00:00 (midnight) January 1st, 1970. 00056 /// @brief 00:00:00 Jan 1, 1970 UTC. 00057 static const TimeValue PosixZeroTime; 00058 00059 /// A constant TimeValue for the Win32 base time which is 00060 /// 00:00:00 (midnight) January 1st, 1601. 00061 /// @brief 00:00:00 Jan 1, 1601 UTC. 00062 static const TimeValue Win32ZeroTime; 00063 00064 /// @} 00065 /// @name Types 00066 /// @{ 00067 public: 00068 typedef int64_t SecondsType; ///< Type used for representing seconds. 00069 typedef int32_t NanoSecondsType; ///< Type used for representing nanoseconds. 00070 00071 enum TimeConversions { 00072 NANOSECONDS_PER_SECOND = 1000000000, ///< One Billion 00073 MICROSECONDS_PER_SECOND = 1000000, ///< One Million 00074 MILLISECONDS_PER_SECOND = 1000, ///< One Thousand 00075 NANOSECONDS_PER_MICROSECOND = 1000, ///< One Thousand 00076 NANOSECONDS_PER_MILLISECOND = 1000000,///< One Million 00077 NANOSECONDS_PER_POSIX_TICK = 100, ///< Posix tick is 100 Hz (10ms) 00078 NANOSECONDS_PER_WIN32_TICK = 100, ///< Win32 tick is 100 Hz (10ms) 00079 }; 00080 00081 /// @} 00082 /// @name Constructors 00083 /// @{ 00084 public: 00085 /// Caller provides the exact value in seconds and nanoseconds. The 00086 /// \p nanos argument defaults to zero for convenience. 00087 /// @brief Explicit constructor 00088 explicit TimeValue (SecondsType seconds, NanoSecondsType nanos = 0) 00089 : seconds_( seconds ), nanos_( nanos ) { this->normalize(); } 00090 00091 /// Caller provides the exact value as a double in seconds with the 00092 /// fractional part representing nanoseconds. 00093 /// @brief Double Constructor. 00094 explicit TimeValue( double new_time ) 00095 : seconds_( 0 ) , nanos_ ( 0 ) { 00096 SecondsType integer_part = static_cast<SecondsType>( new_time ); 00097 seconds_ = integer_part; 00098 nanos_ = static_cast<NanoSecondsType>( (new_time - 00099 static_cast<double>(integer_part)) * NANOSECONDS_PER_SECOND ); 00100 this->normalize(); 00101 } 00102 00103 /// This is a static constructor that returns a TimeValue that represents 00104 /// the current time. 00105 /// @brief Creates a TimeValue with the current time (UTC). 00106 static TimeValue now(); 00107 00108 /// @} 00109 /// @name Operators 00110 /// @{ 00111 public: 00112 /// Add \p that to \p this. 00113 /// @returns this 00114 /// @brief Incrementing assignment operator. 00115 TimeValue& operator += (const TimeValue& that ) { 00116 this->seconds_ += that.seconds_ ; 00117 this->nanos_ += that.nanos_ ; 00118 this->normalize(); 00119 return *this; 00120 } 00121 00122 /// Subtract \p that from \p this. 00123 /// @returns this 00124 /// @brief Decrementing assignment operator. 00125 TimeValue& operator -= (const TimeValue &that ) { 00126 this->seconds_ -= that.seconds_ ; 00127 this->nanos_ -= that.nanos_ ; 00128 this->normalize(); 00129 return *this; 00130 } 00131 00132 /// Determine if \p this is less than \p that. 00133 /// @returns True iff *this < that. 00134 /// @brief True if this < that. 00135 int operator < (const TimeValue &that) const { return that > *this; } 00136 00137 /// Determine if \p this is greather than \p that. 00138 /// @returns True iff *this > that. 00139 /// @brief True if this > that. 00140 int operator > (const TimeValue &that) const { 00141 if ( this->seconds_ > that.seconds_ ) { 00142 return 1; 00143 } else if ( this->seconds_ == that.seconds_ ) { 00144 if ( this->nanos_ > that.nanos_ ) return 1; 00145 } 00146 return 0; 00147 } 00148 00149 /// Determine if \p this is less than or equal to \p that. 00150 /// @returns True iff *this <= that. 00151 /// @brief True if this <= that. 00152 int operator <= (const TimeValue &that) const { return that >= *this; } 00153 00154 /// Determine if \p this is greater than or equal to \p that. 00155 /// @returns True iff *this >= that. 00156 /// @brief True if this >= that. 00157 int operator >= (const TimeValue &that) const { 00158 if ( this->seconds_ > that.seconds_ ) { 00159 return 1; 00160 } else if ( this->seconds_ == that.seconds_ ) { 00161 if ( this->nanos_ >= that.nanos_ ) return 1; 00162 } 00163 return 0; 00164 } 00165 00166 /// Determines if two TimeValue objects represent the same moment in time. 00167 /// @brief True iff *this == that. 00168 /// @brief True if this == that. 00169 int operator == (const TimeValue &that) const { 00170 return (this->seconds_ == that.seconds_) && 00171 (this->nanos_ == that.nanos_); 00172 } 00173 00174 /// Determines if two TimeValue objects represent times that are not the 00175 /// same. 00176 /// @return True iff *this != that. 00177 /// @brief True if this != that. 00178 int operator != (const TimeValue &that) const { return !(*this == that); } 00179 00180 /// Adds two TimeValue objects together. 00181 /// @returns The sum of the two operands as a new TimeValue 00182 /// @brief Addition operator. 00183 friend TimeValue operator + (const TimeValue &tv1, const TimeValue &tv2); 00184 00185 /// Subtracts two TimeValue objects. 00186 /// @returns The difference of the two operands as a new TimeValue 00187 /// @brief Subtraction operator. 00188 friend TimeValue operator - (const TimeValue &tv1, const TimeValue &tv2); 00189 00190 /// @} 00191 /// @name Accessors 00192 /// @{ 00193 public: 00194 00195 /// Returns only the seconds component of the TimeValue. The nanoseconds 00196 /// portion is ignored. No rounding is performed. 00197 /// @brief Retrieve the seconds component 00198 SecondsType seconds() const { return seconds_; } 00199 00200 /// Returns only the nanoseconds component of the TimeValue. The seconds 00201 /// portion is ignored. 00202 /// @brief Retrieve the nanoseconds component. 00203 NanoSecondsType nanoseconds() const { return nanos_; } 00204 00205 /// Returns only the fractional portion of the TimeValue rounded down to the 00206 /// nearest microsecond (divide by one thousand). 00207 /// @brief Retrieve the fractional part as microseconds; 00208 uint32_t microseconds() const { 00209 return nanos_ / NANOSECONDS_PER_MICROSECOND; 00210 } 00211 00212 /// Returns only the fractional portion of the TimeValue rounded down to the 00213 /// nearest millisecond (divide by one million). 00214 /// @brief Retrieve the fractional part as milliseconds; 00215 uint32_t milliseconds() const { 00216 return nanos_ / NANOSECONDS_PER_MILLISECOND; 00217 } 00218 00219 /// Returns the TimeValue as a number of microseconds. Note that the value 00220 /// returned can overflow because the range of a uint64_t is smaller than 00221 /// the range of a TimeValue. Nevertheless, this is useful on some operating 00222 /// systems and is therefore provided. 00223 /// @brief Convert to a number of microseconds (can overflow) 00224 uint64_t usec() const { 00225 return seconds_ * MICROSECONDS_PER_SECOND + 00226 ( nanos_ / NANOSECONDS_PER_MICROSECOND ); 00227 } 00228 00229 /// Returns the TimeValue as a number of milliseconds. Note that the value 00230 /// returned can overflow because the range of a uint64_t is smaller than 00231 /// the range of a TimeValue. Nevertheless, this is useful on some operating 00232 /// systems and is therefore provided. 00233 /// @brief Convert to a number of milliseconds (can overflow) 00234 uint64_t msec() const { 00235 return seconds_ * MILLISECONDS_PER_SECOND + 00236 ( nanos_ / NANOSECONDS_PER_MILLISECOND ); 00237 } 00238 00239 /// Converts the TimeValue into the corresponding number of "ticks" for 00240 /// Posix, correcting for the difference in Posix zero time. 00241 /// @brief Convert to unix time (100 nanoseconds since 12:00:00a Jan 1,1970) 00242 uint64_t toPosixTime() const { 00243 uint64_t result = seconds_ - PosixZeroTime.seconds_; 00244 result += nanos_ / NANOSECONDS_PER_POSIX_TICK; 00245 return result; 00246 } 00247 00248 /// Converts the TimeValue into the corresponding number of seconds 00249 /// since the epoch (00:00:00 Jan 1,1970). 00250 uint64_t toEpochTime() const { 00251 return seconds_ - PosixZeroTime.seconds_; 00252 } 00253 00254 /// Converts the TiemValue into the correspodning number of "ticks" for 00255 /// Win32 platforms, correcting for the difference in Win32 zero time. 00256 /// @brief Convert to windows time (seconds since 12:00:00a Jan 1, 1601) 00257 uint64_t toWin32Time() const { 00258 uint64_t result = seconds_ - Win32ZeroTime.seconds_; 00259 result += nanos_ / NANOSECONDS_PER_WIN32_TICK; 00260 return result; 00261 } 00262 00263 /// Provides the seconds and nanoseconds as results in its arguments after 00264 /// correction for the Posix zero time. 00265 /// @brief Convert to timespec time (ala POSIX.1b) 00266 void getTimespecTime( uint64_t& seconds, uint32_t& nanos ) const { 00267 seconds = seconds_ - PosixZeroTime.seconds_; 00268 nanos = nanos_; 00269 } 00270 00271 /// Provides conversion of the TimeValue into a readable time & date. 00272 /// @returns std::string containing the readable time value 00273 /// @brief Convert time to a string. 00274 std::string toString() const; 00275 00276 /// @} 00277 /// @name Mutators 00278 /// @{ 00279 public: 00280 /// The seconds component of the TimeValue is set to \p sec without 00281 /// modifying the nanoseconds part. This is useful for whole second 00282 /// arithmetic. 00283 /// @brief Set the seconds component. 00284 void seconds (SecondsType sec ) { 00285 this->seconds_ = sec; 00286 this->normalize(); 00287 } 00288 00289 /// The nanoseconds component of the TimeValue is set to \p nanos without 00290 /// modifying the seconds part. This is useful for basic computations 00291 /// involving just the nanoseconds portion. Note that the TimeValue will be 00292 /// normalized after this call so that the fractional (nanoseconds) portion 00293 /// will have the smallest equivalent value. 00294 /// @brief Set the nanoseconds component using a number of nanoseconds. 00295 void nanoseconds ( NanoSecondsType nanos ) { 00296 this->nanos_ = nanos; 00297 this->normalize(); 00298 } 00299 00300 /// The seconds component remains unchanged. 00301 /// @brief Set the nanoseconds component using a number of microseconds. 00302 void microseconds ( int32_t micros ) { 00303 this->nanos_ = micros * NANOSECONDS_PER_MICROSECOND; 00304 this->normalize(); 00305 }; 00306 00307 /// The seconds component remains unchanged. 00308 /// @brief Set the nanoseconds component using a number of milliseconds. 00309 void milliseconds ( int32_t millis ) { 00310 this->nanos_ = millis * NANOSECONDS_PER_MILLISECOND; 00311 this->normalize(); 00312 }; 00313 00314 /// @brief Converts from microsecond format to TimeValue format 00315 void usec( int64_t microseconds ) { 00316 this->seconds_ = microseconds / MICROSECONDS_PER_SECOND; 00317 this->nanos_ = (microseconds % MICROSECONDS_PER_SECOND) * 00318 NANOSECONDS_PER_MICROSECOND; 00319 this->normalize(); 00320 } 00321 00322 /// @brief Converts from millisecond format to TimeValue format 00323 void msec( int64_t milliseconds ) { 00324 this->seconds_ = milliseconds / MILLISECONDS_PER_SECOND; 00325 this->nanos_ = (milliseconds % MILLISECONDS_PER_SECOND) * 00326 NANOSECONDS_PER_MILLISECOND; 00327 this->normalize(); 00328 } 00329 00330 /// Converts the \p seconds argument from PosixTime to the corresponding 00331 /// TimeValue and assigns that value to \p this. 00332 /// @brief Convert seconds form PosixTime to TimeValue 00333 void fromEpochTime( SecondsType seconds ) { 00334 seconds_ = seconds + PosixZeroTime.seconds_; 00335 nanos_ = 0; 00336 this->normalize(); 00337 } 00338 00339 /// @} 00340 /// @name Implementation 00341 /// @{ 00342 private: 00343 /// This causes the values to be represented so that the fractional 00344 /// part is minimized, possibly incrementing the seconds part. 00345 /// @brief Normalize to canonical form. 00346 void normalize(); 00347 00348 /// @} 00349 /// @name Data 00350 /// @{ 00351 private: 00352 /// Store the values as a <timeval>. 00353 SecondsType seconds_;///< Stores the seconds part of the TimeVal 00354 NanoSecondsType nanos_; ///< Stores the nanoseconds part of the TimeVal 00355 00356 /// @} 00357 00358 }; 00359 00360 inline TimeValue operator + (const TimeValue &tv1, const TimeValue &tv2) { 00361 TimeValue sum (tv1.seconds_ + tv2.seconds_, tv1.nanos_ + tv2.nanos_); 00362 sum.normalize (); 00363 return sum; 00364 } 00365 00366 inline TimeValue operator - (const TimeValue &tv1, const TimeValue &tv2) { 00367 TimeValue difference (tv1.seconds_ - tv2.seconds_, tv1.nanos_ - tv2.nanos_ ); 00368 difference.normalize (); 00369 return difference; 00370 } 00371 00372 } 00373 } 00374 00375 // vim: sw=2 smartindent smarttab tw=80 autoindent expandtab 00376 #endif