97 lines
1.9 KiB
C
97 lines
1.9 KiB
C
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/* DEC *RoundCents(pDst,pSrc1,cents)
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*
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* ARGUMENT
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* pDst is a pointer to the destination DEC structure.
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* pSrc1 is a ptr to the source1 DEC structure.
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* cents is the int number of cents to round to
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*
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* DESCRIPTION
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* Rounds pSrc1 to the nearest cents pennies, storing result in pDst.
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* For example, if cents == 5, rounds to the nearest nickle.
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* The result always has two decimal places.
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*
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* SIDE EFFECTS
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* pSrc1 remains unchanged and pDst is undefined on error.
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*
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* RETURNS
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* Returns a pointer to the pDst structure unless error,
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* in which case it returns a NULL(a C false). On error, the error
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* is in wGMError, unless an error was already there.
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*
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* POSSIBLE ERROR CODES
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*
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* GM_NULLPOINTER
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* GM_ARGVAL
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* GM_OVERFLOW
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* GM_UNDERFLOW
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*
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* AUTHOR
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* Jared Levy 10/1/89
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* Copyright (C) 1989-1990 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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#include <stdio.h>
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#include "gm.h"
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#include "gmsystem.h"
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DEC *RoundCents(pDst,pSrc1,cents)
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DEC *pDst, *pSrc1;
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int cents;
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{
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register int r;
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unsigned long i;
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DEC *p, dtmp, *tmp=&dtmp;
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_MacStart(GM_ROUNDCNT);
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if (cents<=0) {
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_MacErr(GM_ARGVAL);
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_MacRet(GM_NULL);
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}
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_MacOutVarD(pDst);
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/* round to two decimals */
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if (cents % 2)
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p = RoundDecimal(tmp, pSrc1, 2);
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else
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p = TruncateDecimal(tmp, pSrc1, 2);
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if (!p) {
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_MacRet(GM_NULL);
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}
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_MacDCopy(pDst, tmp);
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if (_MacIsDecZ(tmp)) {
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_MacRet(pDst);
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}
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/* determine remainder of division */
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r = _DivUnsArrByUns(tmp->dc.sl, cents, 5);
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if (r==0) {
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_MacRet(pDst);
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}
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/* round up or down to nearest multiple */
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if ((unsigned) (2*r) >= (unsigned) cents) { /* round up */
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i = (unsigned long) (cents - r);
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pDst->ls.lsl[0] += i;
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if (pDst->ls.lsl[0] < i)
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pDst->ls.lsl[1]++;
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}
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else { /* round down */
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i = (unsigned long) r;
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if (pDst->ls.lsl[0] < i)
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pDst->ls.lsl[1] --;
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pDst->ls.lsl[0] -= i;
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if (_MacIsDecZ(pDst))
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_MacErr(GM_UNDERFLOW);
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}
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_MacRet(pDst);
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}
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