Files
harbour-core/harbour/source/rtl/dates.c
2000-03-17 17:02:40 +00:00

374 lines
11 KiB
C

/*
* $Id$
*/
/*
* Harbour Project source code:
* The Date API (C level)
*
* Copyright 1999 Antonio Linares <alinares@fivetech.com>
* www - http://www.harbour-project.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version, with one exception:
*
* The exception is that if you link the Harbour Runtime Library (HRL)
* and/or the Harbour Virtual Machine (HVM) with other files to produce
* an executable, this does not by itself cause the resulting executable
* to be covered by the GNU General Public License. Your use of that
* executable is in no way restricted on account of linking the HRL
* and/or HVM code into it.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA (or visit
* their web site at http://www.gnu.org/).
*
*/
/*
* The following parts are Copyright of the individual authors.
* www - http://www.harbour-project.org
*
* Copyright 1999 Jose Lalin <dezac@corevia.com>
* hb_dow()
*
* Copyright 1999 David G. Holm <dholm@jsd-llc.com>
* hb_dtoc()
*
* Copyright 1999 Victor Szakats <info@szelvesz.hu>
* hb_dateEncStr()
* hb_dateDecStr()
* hb_dateStrPut()
* hb_dateStrGet()
*
* See doc/license.txt for licensing terms.
*
*/
#include <ctype.h>
#include "hbapi.h"
#include "hbdate.h"
long hb_dateEncode( long lDay, long lMonth, long lYear )
{
HB_TRACE(HB_TR_DEBUG, ("hb_dateEncode(%ld, %ld, %ld)", lDay, lMonth, lYear));
/* Perform date validation */
if( lYear >= 1 && lYear <= 2999 &&
lMonth >= 1 && lMonth <= 12 &&
lDay >= 1 )
{
/* Month, year, and lower day limits are simple,
but upper day limit is dependent upon month and leap year */
USHORT auiDayLimit[ 12 ] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
if( ( ( lYear % 4 == 0 && lYear % 100 != 0 ) || lYear % 400 == 0 ) )
auiDayLimit[ 1 ] = 29;
if( lDay <= ( long ) auiDayLimit[ ( int ) lMonth - 1 ] )
{
long lFactor = ( lMonth < 3 ) ? -1 : 0;
return ( 1461 * ( lFactor + 4800 + lYear ) / 4 ) +
( ( lMonth - 2 - ( lFactor * 12 ) ) * 367 ) / 12 -
( 3 * ( ( lFactor + 4900 + lYear ) / 100 ) / 4 ) +
lDay - 32075;
}
}
return 0;
}
void hb_dateDecode( long lJulian, long * plDay, long * plMonth, long * plYear )
{
HB_TRACE(HB_TR_DEBUG, ("hb_dateDecode(%ld, %p, %p, %p)", lJulian, plDay, plMonth, plYear));
if( lJulian > 0 )
{
long U, V, W, X;
lJulian += 68569;
W = ( lJulian * 4 ) / 146097;
lJulian -= ( ( 146097 * W ) + 3 ) / 4;
X = 4000 * ( lJulian + 1 ) / 1461001;
lJulian -= ( ( 1461 * X ) / 4 ) - 31;
V = 80 * lJulian / 2447;
U = V / 11;
*plDay = lJulian - ( 2447 * V / 80 );
*plMonth = V + 2 - ( U * 12 );
*plYear = X + U + ( W - 49 ) * 100;
}
else
{
*plDay =
*plMonth =
*plYear = 0;
}
}
void hb_dateStrPut( char * szDate, long lDay, long lMonth, long lYear )
{
HB_TRACE(HB_TR_DEBUG, ("hb_dateStrPut(%p, %ld, %ld, %ld)", szDate, lDay, lMonth, lYear));
if( lDay && lMonth && lYear )
{
szDate[ 0 ] = ( lYear / 1000 ) + '0';
szDate[ 1 ] = ( ( lYear % 1000 ) / 100 ) + '0';
szDate[ 2 ] = ( ( lYear % 100 ) / 10 ) + '0';
szDate[ 3 ] = ( lYear % 10 ) + '0';
szDate[ 4 ] = ( lMonth / 10 ) + '0';
szDate[ 5 ] = ( lMonth % 10 ) + '0';
szDate[ 6 ] = ( lDay / 10 ) + '0';
szDate[ 7 ] = ( lDay % 10 ) + '0';
}
else
memset( szDate, ' ', 8 );
}
void hb_dateStrGet( const char * szDate, long * plDay, long * plMonth, long * plYear )
{
HB_TRACE(HB_TR_DEBUG, ("hb_dateStrGet(%s, %p, %p, %p)", szDate, plDay, plMonth, plYear));
if( szDate && szDate[ 8 ] == '\0' )
{
/* Date string has correct length, so attempt to convert */
*plDay = ( ( szDate[ 6 ] - '0' ) * 10 ) + ( szDate[ 7 ] - '0' );
*plMonth = ( ( szDate[ 4 ] - '0' ) * 10 ) + ( szDate[ 5 ] - '0' );
*plYear = ( ( szDate[ 0 ] - '0' ) * 1000 ) + ( ( szDate[ 1 ] - '0' ) * 100 ) +
( ( szDate[ 2 ] - '0' ) * 10 ) + ( szDate[ 3 ] - '0' );
}
else
{
/* Date string missing or bad length, so force an empty date */
*plDay =
*plMonth =
*plYear = 0;
}
}
/* This function always closes the date with a zero byte, so it needs a
9 character long buffer. */
char * hb_dateDecStr( char * szDate, long lJulian )
{
long lDay, lMonth, lYear;
HB_TRACE(HB_TR_DEBUG, ("hb_dateDecStr(%p, %ld)", szDate, lJulian));
hb_dateDecode( lJulian, &lDay, &lMonth, &lYear );
hb_dateStrPut( szDate, lDay, lMonth, lYear );
szDate[ 8 ] = '\0';
return szDate;
}
long hb_dateEncStr( char * szDate )
{
long lDay, lMonth, lYear;
HB_TRACE(HB_TR_DEBUG, ("hb_dateEncStr(%s)", szDate));
hb_dateStrGet( szDate, &lDay, &lMonth, &lYear );
return hb_dateEncode( lDay, lMonth, lYear );
}
/* NOTE: szFormattedDate must be an at least 11 chars wide buffer */
char * hb_dtoc( const char * szDate, char * szFormattedDate, const char * szDateFormat )
{
/*
* NOTE: szFormattedDate must point to a buffer of at least 11 bytes.
* szDateFormat must point to a buffer holding the date format to use.
*/
int format_count, digit_count, size;
HB_TRACE(HB_TR_DEBUG, ("hb_dtoc(%s, %p, %s)", szDate, szFormattedDate, szDateFormat));
/*
* Determine the maximum size of the formatted date string
*/
size = strlen( szDateFormat );
if( size > 10 ) size = 10;
if( szDate && szFormattedDate && strlen( szDate ) == 8 ) /* A valid date is always 8 characters */
{
const char * szPtr;
int digit;
BOOL used_d, used_m, used_y;
format_count = 0;
used_d = used_m = used_y = FALSE;
szPtr = szDateFormat;
while( format_count < size )
{
digit = toupper( *szPtr );
szPtr++;
digit_count = 1;
while( toupper( *szPtr ) == digit && format_count < size )
{
szPtr++;
if( format_count + digit_count < size ) digit_count++;
}
switch( digit )
{
case 'D':
switch( digit_count )
{
case 4:
if( ! used_d && format_count < size )
{
szFormattedDate[ format_count++ ] = '0';
digit_count--;
}
case 3:
if( ! used_d && format_count < size )
{
szFormattedDate[ format_count++ ] = '0';
digit_count--;
}
case 2:
if( ! used_d && format_count < size )
{
szFormattedDate[ format_count++ ] = szDate[ 6 ];
digit_count--;
}
default:
if( ! used_d && format_count < size )
{
szFormattedDate[ format_count++ ] = szDate[ 7 ];
digit_count--;
}
while( digit_count-- > 0 && format_count < size ) szFormattedDate[ format_count++ ] = digit;
}
used_d = TRUE;
break;
case 'M':
switch ( digit_count )
{
case 4:
if( ! used_m && format_count < size )
{
szFormattedDate[ format_count++ ] = '0';
digit_count--;
}
case 3:
if( ! used_m && format_count < size )
{
szFormattedDate[ format_count++ ] = '0';
digit_count--;
}
case 2:
if( ! used_m && format_count < size )
{
szFormattedDate[ format_count++ ] = szDate[ 4 ];
digit_count--;
}
default:
if( ! used_m && format_count < size )
{
szFormattedDate[ format_count++ ] = szDate[ 5 ];
digit_count--;
}
while( digit_count-- > 0 && format_count < size ) szFormattedDate[ format_count++ ] = digit;
}
used_m = TRUE;
break;
case 'Y':
switch( digit_count )
{
case 4:
if( ! used_y && format_count < size )
{
szFormattedDate[ format_count++ ] = szDate[ 0 ];
digit_count--;
}
case 3:
if( ! used_y && format_count < size )
{
szFormattedDate[ format_count++ ] = szDate[ 1 ];
digit_count--;
}
case 2:
if( ! used_y && format_count < size )
{
szFormattedDate[ format_count++ ] = szDate[ 2 ];
digit_count--;
}
default:
if( ! used_y && format_count < size )
{
szFormattedDate[ format_count++ ] = szDate[ 3 ];
digit_count--;
}
while( digit_count-- > 0 && format_count < size ) szFormattedDate[ format_count++ ] = digit;
}
used_y = TRUE;
break;
default:
while( digit_count-- > 0 && format_count < size ) szFormattedDate[ format_count++ ] = digit;
}
}
}
else
{
/* Not a valid date string, so return a blank date with separators */
format_count = size; /* size is either 8 or 10 */
strncpy( szFormattedDate, szDateFormat, size );
for( digit_count = 0; digit_count < size; digit_count++ )
{
switch( szFormattedDate[ digit_count ] )
{
case 'D':
case 'd':
case 'M':
case 'm':
case 'Y':
case 'y':
szFormattedDate[ digit_count ] = ' ';
}
}
}
szFormattedDate[ format_count ] = '\0';
return szFormattedDate;
}
long hb_dow( long lDay, long lMonth, long lYear )
{
HB_TRACE(HB_TR_DEBUG, ("hb_dow(%ld, %ld, %ld)", lDay, lMonth, lYear));
if( lMonth < 3 )
{
lMonth += 13;
lYear--;
}
else
lMonth++;
return ( lDay + 26 * lMonth / 10 +
lYear + lYear / 4 - lYear / 100 + lYear / 400 + 6 ) % 7 + 1;
}