mirror of https://github.com/python/cpython
77 lines
2.0 KiB
C
77 lines
2.0 KiB
C
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/***********************************************************
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Copyright 1991-1995 by Stichting Mathematisch Centrum, Amsterdam,
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The Netherlands.
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All Rights Reserved
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Permission to use, copy, modify, and distribute this software and its
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documentation for any purpose and without fee is hereby granted,
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provided that the above copyright notice appear in all copies and that
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both that copyright notice and this permission notice appear in
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supporting documentation, and that the names of Stichting Mathematisch
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Centrum or CWI not be used in advertising or publicity pertaining to
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distribution of the software without specific, written prior permission.
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STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO
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THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
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FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE
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FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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******************************************************************/
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/* Just in case you haven't got an atof() around...
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This one doesn't check for bad syntax or overflow,
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and is slow and inaccurate.
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But it's good enough for the occasional string literal... */
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <ctype.h>
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double atof(s)
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char *s;
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{
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double a = 0.0;
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int e = 0;
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int c;
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while ((c = *s++) != '\0' && isdigit(c)) {
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a = a*10.0 + (c - '0');
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}
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if (c == '.') {
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while ((c = *s++) != '\0' && isdigit(c)) {
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a = a*10.0 + (c - '0');
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e = e-1;
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}
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}
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if (c == 'e' || c == 'E') {
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int sign = 1;
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int i = 0;
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c = *s++;
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if (c == '+')
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c = *s++;
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else if (c == '-') {
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c = *s++;
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sign = -1;
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}
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while (isdigit(c)) {
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i = i*10 + (c - '0');
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c = *s++;
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}
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e += i*sign;
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}
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while (e > 0) {
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a *= 10.0;
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e--;
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}
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while (e < 0) {
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a *= 0.1;
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e++;
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}
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return a;
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}
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