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#include <ctype.h>
#include "pdefs.h"
#include "pcvt.h"
#include "precision.h"
/*
* ascii to precision (modeled after atoi)
* leading whitespace skipped
* an optional leading '-' or '+' followed by digits '0'..'9'
* leading 0's Ok
* stops at first unrecognized character
*
* Returns: pUndef if an invalid argument (pUndef or nondigit as 1st digit)
*/
precision atop(chp)
register char *chp;
{
precision res = pUndef;
precision clump = pUndef;
int sign = 0;
register int ch;
register accumulator temp;
accumulator x;
register int i;
if (chp != (char *) 0) {
while (isspace(*chp)) chp++; /* skip whitespace */
if (*chp == '-') {
sign = 1;
++chp;
} else if (*chp == '+') {
++chp;
}
if (isdigit(ch = * (unsigned char *) chp)) {
pset(&res, pzero);
pset(&clump, utop(aDigit));
do {
i = aDigitLog-1;
temp = ch - '0';
do {
if (!isdigit(ch = * (unsigned char *) ++chp)) goto atoplast;
temp = temp * aBase + (ch - '0');
} while (--i > 0);
pset(&res, padd(pmul(res, clump), utop(temp)));
} while (isdigit(ch = * (unsigned char *) ++chp));
goto atopdone;
atoplast:
x = aBase;
while (i++ < aDigitLog-1) {
x *= aBase;
}
pset(&res, padd(pmul(res, utop(x)), utop(temp)));
atopdone:
if (sign) {
pset(&res, pneg(res));
}
}
}
pdestroy(clump);
return presult(res);
}
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