ftostr.c

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/************************************************************************/
/**

   \file       ftostr.c
   
   \version    V1.4
   \date       07.07.14
   \brief      Convert a REAL to a string
   
   \copyright  (c) UCL / Dr. Andrew C. R. Martin 1991-2014
   EMail:      andrew@bioinf.org.uk

**************************************************************************

   This program is not in the public domain, but it may be copied
   according to the conditions laid out in the accompanying file
   COPYING.DOC

   The code may not be sold commercially or included as part of a 
   commercial product except as described in the file COPYING.DOC.

**************************************************************************

   \par
               Institute of Structural & Molecular Biology,
               University College London,
               Gower Street,
               London.
               WC1E 6BT.
   \par
               andrew@bioinf.org.uk
               andrew.martin@ucl.ac.uk
               
**************************************************************************

   This code is NOT IN THE PUBLIC DOMAIN, but it may be copied
   according to the conditions laid out in the accompanying file
   COPYING.DOC.

   The code may be modified as required, but any modifications must be
   documented so that the person responsible can be identified.

   The code may not be sold commercially or included as part of a 
   commercial product except as described in the file COPYING.DOC.

**************************************************************************

   Description:
   ============

   Convert a REAL to a string

**************************************************************************

   Usage:
   ======

**************************************************************************

   Revision History:
   =================
-  V1.0  22.11.95 Original - Routines from general.c
-  V1.1  09.10.97 Fixed inconsistent handling of %.0f between C libs
-  V1.2  14.11.97 Another fix to same
-  V1.3  03.06.05 Tidied up to stop warnings under GCC 3.2.2
-  V1.4  07.07.14 Use bl prefix for functions By: CTP

*************************************************************************/
/* Doxygen
   -------
   #GROUP    General Programming
   #SUBGROUP String handling
   #FUNCTION  blFtostr()
   Convert a REAL to a string using precision decimal places. If 
   precision is negative, use e-form, otherwise use f-form. This is used
   to generate precisely formatted string versions of numbers for
   applications where the appearance of a numeric value is important.
*/
/************************************************************************/
/* Includes
*/
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#include "MathType.h"
#include "SysDefs.h"
#include "macros.h"

/************************************************************************/
/* Defines and macros
*/

/************************************************************************/
/* Globals
*/

/************************************************************************/
/* Prototypes
*/

/************************************************************************/
/*>char *blFtostr(char *str, int maxlen, REAL x, int precision)
   ------------------------------------------------------------
*//**

   \param[out]    *str       String version of number
   \param[in]     maxlen     Max length for f-form. Switches to e-form
                             if exceeded
   \param[in]     x          Number to convert
   \param[in]     precision  Number of decimal places
                             If negative, use e-form rather than f-form
   \return                     Same as str

   Convert a REAL to a string using precision decimal places. If 
   precision is negative, use e-form, otherwise use f-form. This is used
   to generate precisely formatted string versions of numbers for
   applications where the appearance of a numeric value is important.

-  01.07.92 Original
-  07.07.92 Changed to stop value of -0.0
-  24.07.92 Added maxlen parameter. If the f-form will exceed this number
            of characters we switch to e-form autmatically
-  28.07.92 If precision -ve, is never < maxlen-5
-  27.07.93 Changed to double precision I/O
-  09.10.97 If precision is 0 prints as an integer since C libraries
            handle "%.0f" inconsistently
-  14.11.97 Oops, had forgotten to fix this in the check for e-form
-  03.06.05 Tidied up some loops to stop warnings under GCC 3.2.2
-  07.07.14 Use bl prefix for functions By: CTP
*/
char *blFtostr(char  *str,
               int   maxlen,
               REAL  x,
               int   precision)
{
   char   fmt[8],
          *ptr;
   int    i;
   REAL   val;
   
   /* If usiing e-form, check whether string will fit                   */
   if(precision > 0)
   {
      REAL lgx;
      int  len;
      
      lgx = log10(ABS(x));       /* Number of pre-dp places - 1         */
      if(lgx < 0.0) lgx = 0.1;   /* i.e. If x<1.0, 1 p-dp after rounding*/
      len = (int)ceil(lgx);      /* Round up to number of pre-dp places */
      len += precision + 2;      /* dp and '\0'                         */
      
      if(len > maxlen)           /* String too long                     */
      {
         if(precision == 0)   precision  = -1;  /* Set to -1            */
         else                 precision *= -1;  /* Switch to e-form     */
      }
   }
   
   /* 09.10.97 Added check on 0 precision                               */
   if((precision != 0) && (precision < -1*(maxlen-5))) 
      precision = -1*(maxlen-5);

   if(precision > 0)             /* 09.10.97 Changed from >=            */
   {
      sprintf(fmt,"%%.%dlf",precision);
   }
   else
   {
      precision = ABS(precision);
      sprintf(fmt,"%%.%dle",precision);
   }
   if(precision == 0)            /* Added 09.10.97                      */
   {
      sprintf(str,"%d",(int)(x+0.5));
   }
   else
   {
      sprintf(str,fmt,x);
   }
   

   if(!strchr(str,'e'))                   /* Not e-form                 */
   {
      if(precision == 0)
      {
         /* Terminate string at .                                       */
         ptr = str;
         while(*ptr)
         {
            if(*ptr++ == '.')
            {
               *ptr = '\0';
               break;
            }
         }
      }
      else
      {
         if((ptr = strchr(str,'.'))!=NULL)   /* Contains a decimal point*/
         {
            ptr++;
            for(i=0; *ptr; ptr++, i++);
            if(i<precision)               /* Fewer places than precision*/
            {
               /* Pad with zeros                                        */
               for( ; i<precision; i++) *ptr++ = '0';
               *ptr = '\0';
            }
         }
         else                             /* No decimal point           */
         {
            /* Move to end of string                                    */
            for(ptr = str; *ptr; ptr++);
            /* Put in a dp                                              */
            *ptr++ = '.';
            /* Pad with zeros                                           */
            for(i=0; i<precision; i++) *ptr++ = '0';
            *ptr = '\0';
         }
      }
   }
      
   if(str[strlen(str)-1] == '.') str[strlen(str)-1] = '\0';
   
   /* Strip any leading spaces                                          */
   /* 03.06.05 Tidied loop for gcc 3.2.2                                */
   /* 30.09.05 Fixed the warning: operation on `i' may be undefined     */
   while(str[0] == ' ')
   {
      i=0;
      while(i<strlen(str))
      {
         str[i] = str[i+1];
         i++;
      }
   }
   

   /* Remove any leading minus sign if value is 0.0                     */
   sscanf(str,"%lf",&val);
   if(val == 0.0 && str[0] == '-')
   {
      /* 03.06.05 Tidied loop for gcc 3.2.2                             */
      /* 30.09.05 Fixed the warning: operation on `i' may be undefined  */
      i=0;
      while(i<strlen(str))
      {
         str[i] = str[i+1];
         i++;
      }
   }

   return(str);
}