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//===========================================================================
//
// strtod.cxx
//
// ISO String to double-precision floating point conversion
//
//===========================================================================
// ####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
//
// eCos 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 2 or (at your option) any later
// version.
//
// eCos 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 eCos; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
//
// As a special exception, if other files instantiate templates or use
// macros or inline functions from this file, or you compile this file
// and link it with other works to produce a work based on this file,
// this file does not by itself cause the resulting work to be covered by
// the GNU General Public License. However the source code for this file
// must still be made available in accordance with section (3) of the GNU
// General Public License v2.
//
// This exception does not invalidate any other reasons why a work based
// on this file might be covered by the GNU General Public License.
// -------------------------------------------
// ####ECOSGPLCOPYRIGHTEND####
//===========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s): jlarmour
// Contributors:
// Date: 2000-04-30
// Purpose:
// Description:
// Usage:
//
//####DESCRIPTIONEND####
//
//===========================================================================
// CONFIGURATION
#include <pkgconf/libc_stdlib.h> // Configuration header
// Include strtod()?
#if defined(CYGFUN_LIBC_strtod)
// INCLUDES
#include <cyg/infra/cyg_type.h> // Common type definitions and support
#include <cyg/infra/cyg_trac.h> // Tracing support
#include <cyg/infra/cyg_ass.h> // Assertion support
#include <stddef.h> // NULL, wchar_t and size_t from compiler
#include <stdlib.h> // Main header for stdlib functions
#include <ctype.h> // isspace() and isdigit()
#include <float.h> // DBL_MIN_10_EXP and DBL_MAX_10_EXP
#include <math.h> // HUGE_VAL
#include <errno.h> // errno
// CONSTANTS
#define MAXE (DBL_MAX_10_EXP)
#define MINE (DBL_MIN_10_EXP)
// flags
#define SIGN 0x01
#define ESIGN 0x02
#define DECP 0x04
// MACROS
#define Ise(c) ((c == 'e') || (c == 'E'))
#define Issign(c) ((c == '-') || (c == '+'))
#define Val(c) ((c - '0'))
// FUNCTIONS
/*
* [atw] multiply 64 bit accumulator by 10 and add digit.
* The KA/CA way to do this should be to use
* a 64-bit integer internally and use "adjust" to
* convert it to float at the end of processing.
*/
static int
ten_mul(double *acc, int digit)
{
/* [atw] Crude, but effective (at least on a KB)...
*/
*acc *= 10;
*acc += digit;
return 0; /* no overflow */
} // ten_mul()
/*
* compute 10**x by successive squaring.
*/
static const double
exp10(unsigned x)
{
static double powtab[] = {1.0,
10.0,
100.0,
1000.0,
10000.0};
if (x < (sizeof(powtab)/sizeof(double)))
return powtab[x];
else if (x & 1)
return 10.0 * exp10(x-1);
else
return exp10(x/2) * exp10(x/2);
} // exp10()
/*
* return (*acc) scaled by 10**dexp.
*/
static double
adjust(double *acc, int dexp, int sign)
/* *acc the 64 bit accumulator */
/* dexp decimal exponent */
/* sign sign flag */
{
double r;
if (dexp > MAXE)
{
errno = ERANGE;
return (sign) ? -HUGE_VAL : HUGE_VAL;
}
else if (dexp < MINE)
{
errno = ERANGE;
return 0.0;
}
r = *acc;
if (sign)
r = -r;
if (dexp==0)
return r;
if (dexp < 0)
return r / exp10(abs(dexp));
else
return r * exp10(dexp);
} // adjust()
externC double
strtod( const char *nptr, char **endptr )
{
const char *start=nptr;
double accum = 0.0;
int flags = 0;
int texp = 0;
int e = 0;
int conv_done = 0;
double retval;
CYG_REPORT_FUNCNAMETYPE( "strtod", "returning %f" );
CYG_CHECK_DATA_PTR( nptr, "nptr is an invalid pointer!" );
// endptr is allowed to be NULL, but if it isn't, we check it
if (endptr != NULL)
CYG_CHECK_DATA_PTR( endptr, "endptr is an invalid pointer!" );
while(isspace(*nptr)) nptr++;
if(*nptr == '\0')
{ /* just leading spaces */
if(endptr != NULL) *endptr = (char *)start;
return 0.0;
}
if(Issign(*nptr))
{
if(*nptr == '-') flags = SIGN;
if(*++nptr == '\0')
{ /* "+|-" : should be an error ? */
if(endptr != NULL) *endptr = (char *)start;
return 0.0;
}
}
for(; (isdigit(*nptr) || (*nptr == '.')); nptr++)
{
conv_done = 1;
if(*nptr == '.')
flags |= DECP;
else
{
if( ten_mul(&accum, Val(*nptr)) ) texp++;
if(flags & DECP) texp--;
}
}
if(Ise(*nptr))
{
conv_done = 1;
if(*++nptr != '\0') /* skip e|E */
{ /* ! ([nptr]xxx[.[yyy]]e) */
while(isspace(*nptr)) nptr++; /* Ansi allows spaces after e */
if(*nptr != '\0')
{ /* ! ([nptr]xxx[.[yyy]]e[space]) */
if(Issign(*nptr))
if(*nptr++ == '-') flags |= ESIGN;
if(*nptr != '\0')
{ /* ! ([nptr]xxx[.[yyy]]e[nptr]) -- error?? */
for(; isdigit(*nptr); nptr++)
if (e < MAXE) /* prevent from grossly overflowing */
e = e*10 + Val(*nptr);
/* dont care what comes after this */
if(flags & ESIGN)
texp -= e;
else
texp += e;
}
}
}
}
if(endptr != NULL)
*endptr = (char *)((conv_done) ? nptr : start);
retval = adjust(&accum, (int)texp, (int)(flags & SIGN));
CYG_REPORT_RETVAL( retval );
return retval;
} // strtod()
#endif // if defined(CYGFUN_LIBC_strtod)
// EOF strtod.cxx
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