strtof.c File Reference

#include "c.h"
#include <float.h>
#include <math.h>

Include dependency graph for strtof.c:

Go to the source code of this file.

Functions
float	pg_strtof (const char *nptr, char **endptr)

Function Documentation

pg_strtof()

float pg_strtof	(	const char *	nptr,
		char **	endptr
	)

Definition at line 30 of file strtof.c.

{
    int         caller_errno = errno;
    float       fresult;
    char       *myendptr;
 
    errno = 0;
    fresult = (strtof) (nptr, &myendptr);
    if (endptr)
        *endptr = myendptr;
    if (errno)
    {
        /* On error, just return the error to the caller. */
        return fresult;
    }
    else if ((myendptr == nptr) || isnan(fresult) ||
             ((fresult >= FLT_MIN || fresult <= -FLT_MIN) && !isinf(fresult)))
    {
        /*
         * If we got nothing parseable, or if we got a non-0 non-subnormal
         * finite value (or NaN) without error, then return that to the caller
         * without error.
         */
        errno = caller_errno;
        return fresult;
    }
    else
    {
        /*
         * Try again.  errno is already 0 here, and we assume that the endptr
         * won't be any different.
         */
        double      dresult = strtod(nptr, NULL);
 
        if (errno)
        {
            /* On error, just return the error */
            return fresult;
        }
        else if ((dresult == 0.0 && fresult == 0.0) ||
                 (isinf(dresult) && isinf(fresult) && (fresult == dresult)))
        {
            /* both values are 0 or infinities of the same sign */
            errno = caller_errno;
            return fresult;
        }
        else if ((dresult > 0 && dresult <= FLT_MIN && (float) dresult != 0.0) ||
                 (dresult < 0 && dresult >= -FLT_MIN && (float) dresult != 0.0))
        {
            /* subnormal but nonzero value */
            errno = caller_errno;
            return (float) dresult;
        }
        else
        {
            errno = ERANGE;
            return fresult;
        }
    }
}