campo-sirio/arch/timedate.cpp

458 lines
11 KiB
C++
Executable File

//
// TIMEDATE.CPP
//
// Source file for ArchiveLib 1.0
//
// Copyright (c) Greenleaf Software, Inc. 1994
// All Rights Reserved
//
// CONTENTS
//
// ALTimeDate::operator new()
// ALTimeDate::ALTimeDate()
// ALTimeDate::~ALTimeDate()
// ALTimeDate::ToJulian()
// ALTimeDate::FromJulian()
// ALTimeDate::GetUnixTime()
// ALTimeDate::SetTimeDate(long)
// ALTimeDate::SetTimeDate(struct tm *)
// ALTimeDate::GetTimeDate()
//
// DESCRIPTION
//
// This file contains all of the member functions of class ALTimeDate.
// This class is used only by ALStorage, but it seemed like a good
// idea to break it out in a separate class. A lot of the code in here
// came straight out of CommLib.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
//
#include "arclib.h"
#pragma hdrstop
#include <time.h>
#include "timedate.h"
//
// void * ALTimeDate::operator new( size_t size )
//
// ARGUMENTS:
//
// size : The number of bytes needed to create a new ALTimeDate object.
//
// RETURNS
//
// A pointer to the newly allocated storage area, or 0 if no storage
// was available.
//
// DESCRIPTION
//
// When using a DLL, it is easy to get into a dangerous situation when
// creating objects whose ctor and dtor are both in the DLL. The problem
// arises because when you create an object using new, the memory for
// the object will be allocated from the EXE. However, when you destroy
// the object using delete, the memory is freed inside the DLL. Since
// the DLL doesn't really own that memory, bad things can happen.
//
// But, you say, won't the space just go back to the Windows heap regardless
// of who tries to free it? Maybe, but maybe not. If the DLL is using
// a subsegment allocation scheme, it might do some sort of local free
// before returning the space to the windows heap. That is the point where
// you could conceivably cook your heap.
//
// By providing our own version of operator new inside this class, we
// ensure that all memory allocation for the class will be done from
// inside the DLL, not the EXE calling the DLL.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
#if defined( AL_BUILDING_DLL )
void AL_DLL_FAR * AL_PROTO ALTimeDate::operator new( size_t size )
{
return ::new char[ size ];
}
#endif
//
// ALTimeDate::ALTimeDate()
//
// ARGUMENTS:
//
// None.
//
// RETURNS
//
// None.
//
// DESCRIPTION
//
// All the constructor does is initialize the data members. By
// setting the year to an invalid value of 0, we can always see
// that the time date stamp for a file hasn't been initialized.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
AL_PROTO ALTimeDate::ALTimeDate()
{
miYear = 0; //This is an illegal year, means it is uninitialized
miMonth = 0;
miDate = 0;
miHour = 0;
miMinute = 0;
miSecond = 0;
}
//
// ALTimeDate::~ALTimeDate()
//
// ARGUMENTS:
//
// None.
//
// RETURNS
//
// None.
//
// DESCRIPTION
//
// The destructor has nothing to do.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
AL_PROTO ALTimeDate::~ALTimeDate()
{
}
//
// long ALTimeDate::ToJulian()
//
// ARGUMENTS:
//
// None.
//
// RETURNS
//
// A Julian day.
//
// DESCRIPTION
//
// This function is used to make a Julian day number from a normal
// month/day/year thing. We need a Julian day in order to make a
// UNIX style time stamp. The UNIX time stamp is used to store
// time stamps in Archive directories.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
long AL_PROTO ALTimeDate::ToJulian()
{
return (long)( miDate - 32076)
+ 1461L * ( miYear + 4800L + ( miMonth - 14) / 12) / 4
+ 367 * ( miMonth - 2 - ( miMonth - 14) / 12 * 12) / 12
- 3 * (( miYear + 4900L + ( miMonth - 14) / 12) / 100) / 4
+ 1;
}
//
// void ALTimeDate::FromJulian( long jdn )
//
// ARGUMENTS:
//
// jdn : A julian date number, ideally one produced by ToJulian().
//
// RETURNS
//
// Nothing.
//
// DESCRIPTION
//
// This function is used to convert a julian date to a normal
// year/month/day. Time/date stamps are stored in Archives in
// UNIX format. This function is needed to convert a UNIX
// time stamp to a normal mm/dd/yy.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
void AL_PROTO ALTimeDate::FromJulian( long jdn )
{
long x;
long z;
long m;
long d;
long y;
const long daysPer400Years = 146097L;
const long fudgedDaysPer4000Years = 1460970L + 31;
x = jdn + 68569L;
z = 4 * x / daysPer400Years;
x = x - (daysPer400Years * z + 3) / 4;
y = 4000 * (x + 1) / fudgedDaysPer4000Years;
x = x - 1461 * y / 4 + 31;
m = 80 * x / 2447;
d = x - 2447 * m / 80;
x = m / 11;
m = m + 2 - 12 * x;
y = 100 * (z - 49) + y + x;
//
// I don't know whether or not we could eliminate these temporary longs
//
miYear = (short int) y;
miMonth = (short int) m;
miDate = (short int) d;
}
//
// long ALTimeDate::GetUnixTime()
//
// ARGUMENTS:
//
// None.
//
// RETURNS
//
// A UNIX time, converted from the internal m/d/y h:m:s data.
//
// DESCRIPTION
//
// This function is used to convert the m/d/y h:m:s time stamp for a file
// into a UNIX time stamp. The UNIX time stamp is a 32 bit long that
// is used to store time stamps in an Archive.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
long AL_PROTO ALTimeDate::GetUnixTime()
{
const long UnixFirstDay = 2440588L;
long result;
result = ToJulian();
result -= UnixFirstDay;
if ( result >= 0L ) {
result *= 3600L * 24;
result += 3600L * miHour;
result += 60L * miMinute;
result += miSecond;
} else
result = 0L;
return result;
}
//
// void ALTimeDate::SetTimeDate( long unix_time )
//
// ARGUMENTS:
//
// unix_time : A long integer in UNIX timestamp format.
//
// RETURNS
//
// Nothing.
//
// DESCRIPTION
//
// This function is called when we are reading a directory in from
// an archive. It is used to set the internal data members of an
// ALTimeDate object, after converting from unix time.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
void AL_PROTO ALTimeDate::SetTimeDate( long unix_time )
{
const long UnixFirstDay = 2440588L;
long jd = unix_time / ( 3600L * 24 );
long hms = unix_time % ( 3600L * 24 );
FromJulian( jd + UnixFirstDay );
miHour = (short int) ( hms / 3600 );
hms -= 3600L * miHour;
miMinute = (short int) ( hms / 60 );
miSecond = (short int) ( hms - ( miMinute * 60 ) );
}
//
// void ALTimeDate::SetTimeDate( struct tm *tblock )
//
// ARGUMENTS:
//
// tblock : A time date stamp as used by the C run time library.
//
// RETURNS
//
// Nothing.
//
// DESCRIPTION
//
// When working with DOS files, time stamps are read in to a structure
// in the struct tm format. This function provides an easy way to convert
// the structure into our internal format. When a DOS file is opened
// using Open(), this function is called.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
void AL_PROTO ALTimeDate::SetTimeDate( struct tm AL_DLL_FAR *tblock )
{
AL_ASSERT( tblock != 0, "SetTimeDate: passing illegal null parameter" );
miYear = (short int) ( tblock->tm_year + 1900 );
miMonth = (short int) ( tblock->tm_mon + 1 );
miDate = (short int) tblock->tm_mday;
miHour = (short int) tblock->tm_hour;
miMinute = (short int) tblock->tm_min;
miSecond = (short int) tblock->tm_sec;
}
//
// void ALTimeDate::GetTimeDate( struct tm *tblock )
//
// ARGUMENTS:
//
// tblock : A structure in the format used by the C runtime library for
// storing time and date stamps.
//
// RETURNS
//
// Nothing.
//
// DESCRIPTION
//
// This function provides the reverse of SetTimeDate(). You would think
// that we could just set the appropriate members of struct tm, but
// there is a problem with that. struct tm has one element that is
// supposed to be the day of the week, and another that is supposed
// to be the number of the day within the year. We could try to
// figure those out using the julian day function, but since gmtime()
// will figure them out for us, we'll use that instead.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
void AL_PROTO ALTimeDate::GetTimeDate( struct tm AL_DLL_FAR *tblock )
{
AL_ASSERT( tblock != 0, "GetTimeDate: passing illegal null parameter" );
long unix_time = GetUnixTime();
struct tm *result = gmtime( (const time_t *) &unix_time );
if ( result ) {
*tblock = *result;
tblock->tm_isdst = 0;
} else { //This should never happen!
tblock->tm_year = miYear - 1900;
tblock->tm_mon = miMonth - 1;
tblock->tm_mday = miDate;
tblock->tm_hour = miHour;
tblock->tm_min = miMinute;
tblock->tm_sec = miSecond;
tblock->tm_wday = 0;
tblock->tm_yday = 0;
tblock->tm_isdst = 0;
}
}
//
// unsigned short int ALTimeDate::GetDosTime()
//
// ARGUMENTS:
//
// None.
//
// RETURNS
//
// This function returns the time stored in this. The bits of the
// time are packed into the form that is needed by the _dos_setftime()
// format.
//
// DESCRIPTION
//
// When we close a file that needs to have its time and date stamp
// set, we normally use the _dos_setftime() function to do the
// work. It expects to see the time packed into a particular
// sequence of bits in an unsigned short. That is what this
// function does. It packs the bits just the way you want them.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
#if !defined( AL_WIN32S )
unsigned short int AL_PROTO ALTimeDate::GetDosTime()
{
int result;
result = miSecond / 2;
result |= miMinute << 5;
result |= miHour << 11;
return (unsigned short int) result;
}
#endif //#if !defined( AL_WIN32S )
//
// unsigned short int ALTimeDate::GetDosDate()
//
// ARGUMENTS:
//
// None.
//
// RETURNS
//
// This function returns the date stored in this object. The bits of the
// date are packed into the form that is needed by the _dos_setftime()
// format.
//
// DESCRIPTION
//
// When we close a file that needs to have its time and date stamp
// set, we normally use the _dos_setftime() function to do the
// work. It expects to see the date packed into a particular
// sequence of bits in an unsigned short. That is what this
// function does. It packs the bits just the way you want them.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
#if !defined( AL_WIN32S )
unsigned short int AL_PROTO ALTimeDate::GetDosDate()
{
int result;
result = miDate;
result |= miMonth << 5;
result |= (miYear-1980) << 9;
return (unsigned short int ) result;
}
#endif //#if !defined( AL_WIN32S )