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/* str2num.c (convert string to double) */
/***********************************************************************
* This code is part of GLPK (GNU Linear Programming Kit).
* Copyright (C) 2000 Free Software Foundation, Inc.
* Written by Andrew Makhorin <mao@gnu.org>.
*
* GLPK is free software: you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GLPK 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 General Public
* License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GLPK. If not, see <http://www.gnu.org/licenses/>.
***********************************************************************/
#include "misc.h"
#include "stdc.h"
/***********************************************************************
* NAME
*
* str2num - convert character string to value of double type
*
* SYNOPSIS
*
* #include "misc.h"
* int str2num(const char *str, double *val);
*
* DESCRIPTION
*
* The routine str2num converts the character string str to a value of
* double type and stores the value into location, which the parameter
* val points to (in the case of error content of this location is not
* changed).
*
* RETURNS
*
* The routine returns one of the following error codes:
*
* 0 - no error;
* 1 - value out of range;
* 2 - character string is syntactically incorrect. */
int str2num(const char *str, double *val_)
{ int k;
double val;
/* scan optional sign */
k = (str[0] == '+' || str[0] == '-' ? 1 : 0);
/* check for decimal point */
if (str[k] == '.')
{ k++;
/* a digit should follow it */
if (!isdigit((unsigned char)str[k]))
return 2;
k++;
goto frac;
}
/* integer part should start with a digit */
if (!isdigit((unsigned char)str[k]))
return 2;
/* scan integer part */
while (isdigit((unsigned char)str[k]))
k++;
/* check for decimal point */
if (str[k] == '.') k++;
frac: /* scan optional fraction part */
while (isdigit((unsigned char)str[k]))
k++;
/* check for decimal exponent */
if (str[k] == 'E' || str[k] == 'e')
{ k++;
/* scan optional sign */
if (str[k] == '+' || str[k] == '-')
k++;
/* a digit should follow E, E+ or E- */
if (!isdigit((unsigned char)str[k]))
return 2;
}
/* scan optional exponent part */
while (isdigit((unsigned char)str[k]))
k++;
/* check for terminator */
if (str[k] != '\0')
return 2;
/* perform conversion */
{ char *endptr;
val = strtod(str, &endptr);
if (*endptr != '\0')
return 2;
}
/* check for overflow */
if (!(-DBL_MAX <= val && val <= +DBL_MAX))
return 1;
/* check for underflow */
if (-DBL_MIN < val && val < +DBL_MIN)
val = 0.0;
/* conversion has been done */
*val_ = val;
return 0;
}
/* eof */
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