/* ieee-utils/read.c

 * 

 * Copyright (C) 1996, 1997, 1998, 1999, 2000, 2007 Brian Gough

 * 

 * This program 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.

 * 

 * This program 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 this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

 */

#include <config.h>

#include <stdlib.h>

#include <string.h>

#include <gsl/gsl_errno.h>

#include <gsl/gsl_ieee_utils.h>

static int 

lookup_string (const char * p, int * precision, int * rounding, 

               int * exception_mask) ;

int

gsl_ieee_read_mode_string (const char * description, 

                           int * precision, 

                           int * rounding, 

                           int * exception_mask)

{

  char * start ;

  char * end;

  char * p;

  int precision_count = 0 ;

  int rounding_count = 0 ;

  int exception_count = 0 ;

  start = (char *) malloc(strlen(description) + 1) ;

  if (start == 0) 

    {

      GSL_ERROR ("no memory to parse mode string", GSL_ENOMEM) ;

    }

  strcpy (start, description) ;

  p = start ;

  *precision = 0 ;

  *rounding = 0 ;

  *exception_mask = 0 ;

  do {

    int status ;

    int new_precision, new_rounding, new_exception ;

    end = strchr (p,',') ;

    if (end) 

      {

        *end = '\0' ;

        do 

          {

            end++ ;  /* skip over trailing whitespace */

          } 

        while (*end == ' ' || *end == ',') ;

      }

    new_precision = 0 ; 

    new_rounding = 0 ; 

    new_exception = 0 ;

    status = lookup_string (p, &new_precision, &new_rounding, &new_exception) ;

    if (status)

      {

        free(start);

        GSL_ERROR ("unrecognized GSL_IEEE_MODE string.\nValid settings are:\n\n" 

                   "  single-precision double-precision extended-precision\n"

                   "  round-to-nearest round-down round-up round-to-zero\n"

                   "  mask-invalid mask-denormalized mask-division-by-zero\n"

                   "  mask-overflow mask-underflow mask-all\n"

                   "  trap-common trap-inexact\n"

                   "\n"

                   "separated by commas. "

                   "(e.g. GSL_IEEE_MODE=\"round-down,mask-underflow\")",

                   GSL_EINVAL) ;

      }

    if (new_precision) 

      {

        *precision = new_precision ;

        precision_count ++ ;

        if (precision_count > 1)

          {

            free(start);

            GSL_ERROR ("attempted to set IEEE precision twice", GSL_EINVAL) ;

          }

      }

    if (new_rounding) 

      {

        *rounding = new_rounding ;

        rounding_count ++ ;

        if (rounding_count > 1)

          {

            free(start);

            GSL_ERROR ("attempted to set IEEE rounding mode twice", GSL_EINVAL) ;

          }

      }

    if (new_exception) 

      {

        *exception_mask |= new_exception ;

        exception_count ++ ;

      }

    p = end ; 

  } while (end && *p != '\0') ;

  free(start) ;

  return GSL_SUCCESS ;

}

static int 

lookup_string (const char * p, int * precision, int * rounding, 

               int * exception_mask)

{

  if (strcmp(p,"single-precision") == 0) 

    {

      *precision = GSL_IEEE_SINGLE_PRECISION ;

    }

  else if (strcmp(p,"double-precision") == 0) 

    {

      *precision = GSL_IEEE_DOUBLE_PRECISION ;

    }

  else if (strcmp(p,"extended-precision") == 0) 

    {

      *precision = GSL_IEEE_EXTENDED_PRECISION ;

    }

  else if (strcmp(p,"round-to-nearest") == 0) 

    {

      *rounding = GSL_IEEE_ROUND_TO_NEAREST ;

    }

  else if (strcmp(p,"round-down") == 0) 

    {

      *rounding = GSL_IEEE_ROUND_DOWN ;

    }

  else if (strcmp(p,"round-up") == 0) 

    {

      *rounding = GSL_IEEE_ROUND_UP ;

    }

  else if (strcmp(p,"round-to-zero") == 0) 

    {

      *rounding = GSL_IEEE_ROUND_TO_ZERO ;

    }

  else if (strcmp(p,"mask-all") == 0) 

    {

      *exception_mask = GSL_IEEE_MASK_ALL ;

    }

  else if (strcmp(p,"mask-invalid") == 0) 

    {

      *exception_mask = GSL_IEEE_MASK_INVALID ;

    }

  else if (strcmp(p,"mask-denormalized") == 0) 

    {

      *exception_mask = GSL_IEEE_MASK_DENORMALIZED ;

    }

  else if (strcmp(p,"mask-division-by-zero") == 0) 

    {

      *exception_mask = GSL_IEEE_MASK_DIVISION_BY_ZERO ;

    }

  else if (strcmp(p,"mask-overflow") == 0) 

    {

      *exception_mask = GSL_IEEE_MASK_OVERFLOW ;

    }

  else if (strcmp(p,"mask-underflow") == 0) 

    {

      *exception_mask = GSL_IEEE_MASK_UNDERFLOW ;

    }

  else if (strcmp(p,"trap-inexact") == 0) 

    {

      *exception_mask = GSL_IEEE_TRAP_INEXACT ;

    }

  else if (strcmp(p,"trap-common") == 0) 

    {

      return 0 ;

    }

  else

    {

      return 1 ;

    }

  return 0 ;

}