ba237a9d91
Files correlati : Ricompilazione Demo : [ ] Commento : Aggiunti i sorgenti per Greenleaf Math Library (gfm.dll) git-svn-id: svn://10.65.10.50/trunk@10079 c028cbd2-c16b-5b4b-a496-9718f37d4682
145 lines
2.7 KiB
C
Executable File
145 lines
2.7 KiB
C
Executable File
/* void AddDaysToDate365( m2, d2, y2, m1, d1, y1, ndays )
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*
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* ARGUMENTS
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* int m1, d1, y1 - Specify a base date.
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* int *m2, *d2, *y2 - Specify a date to be calculated
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* int ndays - Number of days (+ or -) to be added to base
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*
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* DESCRIPTION
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* A signed number of days (ndays) is added to the base date to form a
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* second date which is transferred to the variables m2,d2,y2. If any of
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* the arguments are NULL on input, an error results.
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*
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* Years < 100 are taken to be in 20th century.
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*
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* Years are considered to have 365 days. Leap years are considered here.
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*
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* SIDE EFFECTS
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* Modified d2, m2, y2.
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*
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* RETURNS
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* None.
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*
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* POSSIBLE ERROR CODES
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*
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* GM_ARGVAL
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* GM_NULLPOINTER
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*
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* AUTHOR
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* Don Killen 03-Feb-1988 16:27:32
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* Copyright (C) 1988-1990 Greenleaf Software Inc. All rights reserved.
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*
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* MODIFICATIONS
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*
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*
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*/
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#include <stdio.h>
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#include "gm.h"
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#include "gmsystem.h"
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void AddDaysToDate365(m2,d2,y2,m1,d1,y1,ndays)
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int m1,*m2,d1,*d2,y1,*y2,ndays;
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{
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long n1;
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int np, x, z, mt, dt=1, dp, ny, t1, t2;
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mbool ly;
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_MacStart(GM_ADATE365);
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if (d2==NULL||m2==NULL||y2==NULL) {
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_MacErr(GM_NULLPOINTER);
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_MacRetV;
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}
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if ( m1<1 || m1>12 || d1<1 || d1>31 || y1<1 || y1>9999 ) {
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_MacErr(GM_ARGVAL);
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_MacRetV;
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}
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if (m1<=2) {
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x=0;
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z=y1-1;
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}
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else {
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x=(4*m1 + 23) / 10;
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z=y1;
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}
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/* compute day # */
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n1 = (long) y1 * 365L + (long) (31*(m1-1) + d1 + z/4 - x)
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+(long) ndays;
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/* estimate year */
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*y2 = (int) ((4L * n1) / 1461L);
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np = (int) (n1 - ((long) (*y2) * 365L + (long) (((*y2) - 1) / 4)));
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/* correct year estimate */
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while (np<1) { /* year too large */
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*y2 = (*y2)-1;
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np = (int) (n1 - ((long)(*y2) * 365L +
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(long) (((*y2)-1) / 4)));
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}
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if ( ((*y2) % 4) == 0)
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ny = 366;
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else
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ny = 365;
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while (np > ny ) { /* year too small */
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*y2 = (*y2)+1;
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np = (int) (n1 - ((long)(*y2) * 365L +
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(long) (((*y2)-1) / 4)));
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}
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/* no leap year in 1700, 1800, 1900 */
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if ((y1>=1700 && y1<=1900) || (*y2>=1700 && *y2<=1900)) {
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t1 = (m1<=2) ? y1-1 : y1;
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t2 = (np<60) ? (*y2)-1 : *y2;
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if (np==60 && ndays<0)
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t2--;
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/* if y1 and y2 fall on different centuries, extra leap year counted */
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np+= ((t2/100) - (t1/100));
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if (np<1) {
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*y2 = *y2-1;
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*m2 = 12;
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*d2 = 31;
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_MacRetV;
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}
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if (np>366) {
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*y2 = *y2+1;
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*m2 = 1;
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*d2 = 1;
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_MacRetV;
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}
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}
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/* handle Jan. & Feb. */
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if (np <= 31) {
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*m2 = 1;
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*d2 = np;
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_MacRetV;
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}
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/* check for leap year */
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ly = ((*y2) % 4 == 0);
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if (np <= 59 + (ly)) {
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*m2 = 2;
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*d2 = np - 31;
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_MacRetV;
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}
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/* handle other months */
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if (ly)
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np--;
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mt = 2;
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do {
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mt++;
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dp = dt;
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dt = np - 31 * (mt - 1) + (4 * mt + 23) / 10;
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} while (dt>=1);
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*m2 = mt-1;
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*d2 = dp;
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_MacRetV;
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}
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