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/* --------------------------------------------------------------------------
timeconv.cpp Functions to perform various time conversion operations.
Copyright (C) 1994, Microsoft Corporation. All rights reserved.
Author: Lindsay Harris - lindsayh
-------------------------------------------------------------------------- */
//#include "tigris.hxx"
#include "stdinc.h"
#include <stdlib.h>
/*
* A handcrafted time zone string to GMT offsets table. This is not * a very good way to handle this. */
static struct{ int iTZOffset; // Arithmetic offset from GMT, in seconds.
char rgchTZName[ 4 ]; // String representation of time zone.
} _TZ_NAME[] ={ { 0, { 'G', 'M', 'T', '\0' } }, { 0, { 'U', 'T', 'C', '\0' } }, { 0, { 'U', 'T', '\0', '\0' } }, { -14400, { 'E', 'D', 'T', '\0' } }, { -18000, { 'E', 'S', 'T', '\0' } }, { -18000, { 'C', 'D', 'T', '\0' } }, { -21600, { 'C', 'S', 'T', '\0' } }, { -21600, { 'M', 'D', 'T', '\0' } }, { -25200, { 'M', 'S', 'T', '\0' } }, { -25200, { 'P', 'D', 'T', '\0' } }, { -28800, { 'P', 'S', 'T', '\0' } }, { 43200, { 'N', 'Z', 'S', '\0' } }, // NZ standard time.
{ 46800, { 'N', 'Z', 'D', '\0' } },};
#define NUM_TZ (sizeof( _TZ_NAME ) / sizeof( _TZ_NAME[ 0 ] ))
// The date Jan 1, 1970 00:00:00 in type FILETIME
#define ft1970high 27111902
#define ft1970low 3577643008
static FILETIME ft1970 = {ft1970low, ft1970high};
// The number of FILETIME units (100's of nanoseconds) in a time_t unit (seconds)
#define dFiletimePerDTime_t 10000000
#define BUNCH_FACTOR 6
#define MESSAGE_ID_SPAN 64
char MsgIdSet[MESSAGE_ID_SPAN] = { 'A','B','C','D','E','F','G','H','I','J','K','L','M', 'N','O','P','Q','R','S','T','U','V','W','X','Y','Z', 'a','b','c','d','e','f','g','h','i','j','k','l','m', 'n','o','p','q','r','s','t','u','v','w','x','y','z', '0','1','2','3','4','5','6','7','8','9','#','$'};
/*
* English language month table. */
static char *rgchMonth[ 12 ] ={ "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec",};
/*
* English language weekday table. */
static char *rgchDayOfWeek[ 7 ] ={ "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat",};
/* --------------------------------------------------------------------------
dwConvertAsciiTime Convert a usenet (unix) style date string into a MOS time value. There seem to be some variations on this format. Time returned is GMT/UNC.
Author: Lindsay Harris - lindsayh
History: 13:49 on Thu 31 Mar 1994 -by- Lindsay Harris [lindsayh] First version.
-------------------------------------------------------------------------- */BOOLConvertAsciiTime( char *pchInput, FILETIME &filetime ){ DWORD dwRet; // Return value, 0 on error.
int iTZOffset = 0; // Time zone offset, if it can be decided.
SYSTEMTIME tm; // Result is built in here.
char *pchTemp;
dwRet = 0;
GetSystemTime(&tm);
// if less then 2 char long, skip everything and use system time (so we won't read invalid data)
if( (strlen(pchInput) > 2) && (pchTemp = strchr( pchInput+2, ':' ) ) ) { /*
* Found a colon, which separates hours and minutes. Probably valid. * The other part of the test is if the preceeding character is a * digit which is also preceeded by either a digit or a space char. * That is, we have either <digit><digit>: or <space><digit>: */ // if it's not <space><digit>:<digit><digit> or <digit><digit>:<digit><digit>, skip everything and use system time
if( isdigit( (UCHAR)*(pchTemp - 1) ) && (isdigit( (UCHAR)*(pchTemp - 2) ) || *(pchTemp - 2) == ' ') && isdigit( (UCHAR)*(pchTemp + 1) ) && isdigit( (UCHAR)*(pchTemp + 2) ) ) { tm.wHour = (WORD)atoi( pchTemp - 2 ); tm.wMinute = (WORD)atoi( pchTemp + 1 );
pchTemp += 3; // Skip to char after minutes digit.
if( *pchTemp == ':' ) { tm.wSecond = (WORD)atoi( pchTemp + 1 ); tm.wMilliseconds = 0;
pchTemp += 3; // Skip :ss to first byte past end.
} else { tm.wSecond = 0; tm.wMilliseconds = 0; }
// Time zone information - much guess work here!
while( *pchTemp && *pchTemp == ' ' ) ++pchTemp;
/*
* Sometimes there is a time zone offset encoded. This starts * with either a + or - sign or a digit, having 4 digits in all. * Otherwise, presume it is some sort of time zone string, * of 3 letters and totally ambiguous as to where it is unless * it happens to be GMT. */
if( *pchTemp == '-' || *pchTemp == '+' || isdigit( (UCHAR)*pchTemp ) ) { // Appears to be numeric value.
int iSign;
iSign = *pchTemp == '-' ? -60 : 60;
if( !isdigit( (UCHAR)*pchTemp ) ) ++pchTemp; // Skip the sign.
// if incorrect formatted, skip the timezone adjustment.
if( isdigit( (UCHAR)*pchTemp ) && isdigit( (UCHAR)*(pchTemp+1) ) && isdigit( (UCHAR)*(pchTemp+2) ) && isdigit( (UCHAR)*(pchTemp+3) ) ) { iTZOffset = (*pchTemp - '0') * 10 + *(pchTemp + 1) - '0'; pchTemp += 2; iTZOffset *= 60; // Into minutes.
iTZOffset += (*pchTemp - '0') * 10 + *(pchTemp + 1) - '0';
iTZOffset *= iSign; // Into seconds.
}
} else { int iIndex;
iTZOffset = 0; // Default to GMT if nothing found.
for( iIndex = 0; iIndex < NUM_TZ; ++iIndex ) { if( !strncmp( pchTemp, _TZ_NAME[ iIndex ].rgchTZName, 3 ) ) { iTZOffset = _TZ_NAME[ iIndex ].iTZOffset; break; } } }
/*
* Now try for the date. The format is day of month, three * letter abbreviation of month, then year, as either 2 or 4 * digits. This is at the start of the string, possibly * preceeded by a 3 letter day of week with following comma. */
pchTemp = pchInput;
// skip over any leading blanks
while( *pchTemp && *pchTemp == ' ' ) ++pchTemp;
// make sure we don't pass the end of string
if( (strlen(pchTemp) > 5) && (*(pchTemp + 3) == ',' ) ) pchTemp += 5; // Skip over day + comma + space.
if( (*pchTemp == ' ' || isdigit( (UCHAR)*pchTemp )) && (*(pchTemp + 1) == ' ' || isdigit( (UCHAR)*(pchTemp + 1) )) ) { // Looks good, so turn into day of month.
int iIndex;
tm.wDay = 0; if( isdigit( (UCHAR)*pchTemp ) ) tm.wDay = *pchTemp - '0';
++pchTemp;
if( isdigit( (UCHAR)*pchTemp ) ) tm.wDay = tm.wDay * 10 + *pchTemp++ - '0';
pchTemp++; // Skip the space before name of month.
// make sure we have month and a space after it
if (strlen(pchTemp) >= 4) { for( iIndex = 0; iIndex < 12; ++iIndex ) { if( strncmp( pchTemp, rgchMonth[ iIndex ], 3 ) == 0 ) { tm.wMonth = iIndex + 1; break; } } pchTemp += 4; iIndex = atoi( pchTemp ); if( iIndex < 50 ) { iIndex += 2000; } else if (iIndex < 100) { iIndex += 1900; }
tm.wYear = (WORD)iIndex; }
}
}
}
return SystemTimeToFileTime( &tm, &filetime ) ;}
/* -----------------------------------------------------------------------
GetArpaDate Returns a pointer to static memory containing the current date in Internet/ARPA standard format.
Author Lindsay Harris - lindasyh
History 13:49 on Wed 20 Apr 1994 -by- Lindsay Harris [lindsayh] First version. Imported to Tigris. Added passed-in buffer, changed year to 4-digit format
----------------------------------------------------------------------- */
char *GetArpaDate( char achReturn[ cMaxArpaDate ] ){
char chSign; // Sign to print.
DWORD dwResult;
int iBias; // Offset relative to GMT.
TIME_ZONE_INFORMATION tzi; // Local time zone data.
SYSTEMTIME stUTC; // The current time in UTC/GMT
dwResult = GetTimeZoneInformation( &tzi ); GetLocalTime( &stUTC );
// Calculate the time zone offset.
iBias = tzi.Bias; if( dwResult == TIME_ZONE_ID_DAYLIGHT ) iBias += tzi.DaylightBias;
/*
* We always want to print the sign for the time zone offset, so * we decide what it is now and remember that when converting. * The convention is that west of the 0 degree meridian has a * negative offset - i.e. add the offset to GMT to get local time. */
if( iBias > 0 ) { chSign = '-'; // Yes, I do mean negative.
} else { iBias = -iBias; chSign = '+'; }
/*
* No major trickery here. We have all the data, so simply * format it according to the rules on how to do this. */
_snprintf( achReturn, cMaxArpaDate , "%s, %02d %s %04d %02d:%02d:%02d %c%02d%02d", rgchDayOfWeek[stUTC.wDayOfWeek], stUTC.wDay, rgchMonth[ stUTC.wMonth - 1 ], stUTC.wYear, stUTC.wHour, stUTC.wMinute, stUTC.wSecond, chSign, (iBias / 60) % 100, iBias % 60 );
return achReturn;}
/* -----------------------------------------------------------------------
GetMessageIDDate
----------------------------------------------------------------------- */
char *GetMessageIDDate( DWORD GroupId, DWORD ArticleId, char achReturn[ cMaxMessageIDDate ] ){ SYSTEMTIME stUTC; // The current time in UTC/GMT
FILETIME ftUTC; DWORD NumSextets = (sizeof(MsgIdSet) / BUNCH_FACTOR)+1; LARGE_INTEGER liMask; LARGE_INTEGER liSextet; LARGE_INTEGER * pliDate;
#if 0
GetSystemTime( &stUTC );
/*
* No major trickery here. We have all the data, so simply * format it according to the rules on how to do this. */
wsprintf( achReturn, "%d%s%d.%02d%02d%02d%04d", stUTC.wYear, rgchMonth[ stUTC.wMonth - 1 ], stUTC.wDay, stUTC.wHour, stUTC.wMinute, stUTC.wSecond, stUTC.wMilliseconds);#endif
// If articles are created sufficiently close, use the sum of grp and art id to create a difference
// NOTE: Only 24 bits are taken so that the difference is within 1.6 secs
DWORD dwGrpArtSuffix = GroupId + ArticleId; dwGrpArtSuffix &= 0x00ffffff;
GetSystemTime( &stUTC ); SystemTimeToFileTime( &stUTC, &ftUTC );
liMask.QuadPart = 0x3F; // Mask to get sextets
pliDate = (LARGE_INTEGER *) (void *) & ftUTC;
// add a 24-bit offset that is a function of the group id and article id
pliDate->QuadPart += dwGrpArtSuffix;
// For each sextet in the date, lookup a char in the lookup array
for(DWORD i=0; i<NumSextets; i++) { liSextet.QuadPart = ( pliDate->QuadPart ) & liMask.QuadPart; liSextet.QuadPart >>= i*BUNCH_FACTOR; liMask.QuadPart <<= BUNCH_FACTOR;
_ASSERT( 0 <= liSextet.QuadPart && liSextet.QuadPart <= MESSAGE_ID_SPAN-1 );
achReturn [i] = MsgIdSet [liSextet.QuadPart]; }
achReturn [i] = '\0';
return achReturn;}
/* -----------------------------------------------------------------------
SystemTimeToTime_T Coverts SYSTEMTIME to time_t.
Returns 0 if date is before 1970 or -1 if far, far into the future.
Author Carl Kadie - carlk
History Thu, 15 Dec 1994 -by- Carl Kadie [carlk] First version.
----------------------------------------------------------------------- */
time_tSystemTimeToTime_T(SYSTEMTIME & st){ FILETIME ft;
// Convert from SYSTEMTIME to FILETIME
SystemTimeToFileTime(&st, &ft);
// If date is before 1970, return 0
if (filetimeGreaterThan(ft1970, ft)) { return 0; } else { // Convert from FILETIME to time_t
ft = filetimeSubtract(ft, ft1970); return dTime_tFromDFiletime(ft); }}
/* -----------------------------------------------------------------------
dTime_tFromDFiletime Converts changes in filetimes (dFiletime) to changes in time_ts (dTime_t)
Do not use to change absolute FILETIME's to absolute time_t's
Returns -1 if the dFiletime overflows the dTime_t
Author Carl Kadie - carlk
History 24 March 1995 - by - Carl Kadie [carlk]
----------------------------------------------------------------------- */
time_tdTime_tFromDFiletime(const FILETIME & ft){ _ASSERT(sizeof(LARGE_INTEGER) == sizeof(FILETIME)); _ASSERT(sizeof(LARGE_INTEGER) == (2 * sizeof(time_t)));
LARGE_INTEGER * pli = (LARGE_INTEGER *)(void *) &ft; LARGE_INTEGER liHold;
liHold.QuadPart = pli->QuadPart / dFiletimePerDTime_t;
if (0 == liHold.HighPart) return (time_t) liHold.LowPart; else return (time_t) -1;}
/* -----------------------------------------------------------------------
filetimeSubtract Subtract two filetimes (or subtract a filetime by a dFiletime)
Author Carl Kadie - carlk
History 24 March 1995 - by - Carl Kadie [carlk]
----------------------------------------------------------------------- */
FILETIMEfiletimeSubtract(const FILETIME & ft1, const FILETIME & ft2){ LARGE_INTEGER li;
LARGE_INTEGER * pli1 = (LARGE_INTEGER *) (void *) & ft1; LARGE_INTEGER * pli2 = (LARGE_INTEGER *) (void *) & ft2;
_ASSERT(0 <= pli1->HighPart && 0 <= pli2->HighPart); //LargeInteger is signed, FILETIME is not
li.QuadPart = pli1->QuadPart - pli2->QuadPart;
return *((FILETIME *)(void *)(&li));}
/* -----------------------------------------------------------------------
filetimeGreaterThan Compare two filetimes
Author Carl Kadie - carlk
History 24 March 1995 - by - Carl Kadie [carlk]
----------------------------------------------------------------------- */
BOOLfiletimeGreaterThan(const FILETIME & ft1, const FILETIME & ft2){ return ((ft1.dwHighDateTime == ft2.dwHighDateTime) && (ft1.dwLowDateTime > ft2.dwLowDateTime)) || (ft1.dwHighDateTime > ft2.dwHighDateTime);}
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