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author | Robert de Bath <rdebath@poboxes.com> | 1996-03-24 21:25:23 +0100 |
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committer | Lubomir Rintel <lkundrak@v3.sk> | 2013-10-23 23:29:54 +0200 |
commit | dcc973ea3e31710429858c99d4f040334ac67c06 (patch) | |
tree | 8883b902eb18eba489957b7f03caa491fd7992a7 /libc/misc/strtod.c | |
parent | fe22c37817ce338fbbc90b239320248c270957fa (diff) | |
download | dev86-dcc973ea3e31710429858c99d4f040334ac67c06.tar.gz |
Import Dev86-0.0.5.tar.gzv0.0.5
Diffstat (limited to 'libc/misc/strtod.c')
-rw-r--r-- | libc/misc/strtod.c | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/libc/misc/strtod.c b/libc/misc/strtod.c new file mode 100644 index 0000000..8acb423 --- /dev/null +++ b/libc/misc/strtod.c @@ -0,0 +1,96 @@ +/* + * strtod.c - This file is part of the libc-8086 package for ELKS, + * Copyright (C) 1995, 1996 Nat Friedman <ndf@linux.mit.edu>. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Library General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library 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 + * Library General Public License for more details. + * + * You should have received a copy of the GNU Library General Public + * License along with this library; if not, write to the Free + * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + * + */ +#include <stdlib.h> +#include <ctype.h> + +double +strtod(const char *nptr, char ** endptr) +{ + unsigned short negative; + double number; + double fp_part; + int exponent; + unsigned short exp_negative; + + /* advance beyond any leading whitespace */ + while (isspace(*nptr)) + nptr++; + + /* check for optional '+' or '-' */ + negative=0; + if (*nptr=='-') + { + negative=1; + nptr++; + } + else + if (*nptr=='+') + nptr++; + + number=0; + while (isdigit(*nptr)) + { + number=number*10+(*nptr-'0'); + nptr++; + } + + if (*nptr=='.') + { + nptr++; + fp_part=0; + while (isdigit(*nptr)) + { + fp_part=fp_part/10.0 + (*nptr-'0')/10.0; + nptr++; + } + number+=fp_part; + } + + if (*nptr=='e' || *nptr=='E') + { + nptr++; + exp_negative=0; + if (*nptr=='-') + { + exp_negative=1; + nptr++; + } + else + if (*nptr=='+') + nptr++; + + exponent=0; + while (isdigit(*nptr)) + { + exponent=exponent*10+(*nptr-'0'); + exponent++; + } + } + + while (exponent) + { + if (exp_negative) + number/=10; + else + number*=10; + exponent--; + } + return (negative ? -number:number); +} |