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Viewing changes to tools/sfio/sfstrtod.c

  • Committer: Bazaar Package Importer
  • Author(s): Stephen M Moraco
  • Date: 2002-02-05 18:52:12 UTC
  • Revision ID: james.westby@ubuntu.com-20020205185212-8i04c70te00rc40y
Tags: upstream-1.7.16
Import upstream version 1.7.16

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tools/sfio/sfstrtod.c
 
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#include        "sfhdr.h"
 
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/*      Convert a Sfdouble_t value represented in an ASCII format into
 
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**      the internal Sfdouble_t representation.
 
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**
 
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**      Written by Kiem-Phong Vo.
 
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*/
 
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#define BATCH   (2*sizeof(int)) /* accumulate this many digits at a time */
 
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#define IPART           0       /* doing integer part */
 
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#define FPART           1       /* doing fractional part */
 
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#define EPART           2       /* doing exponent part */
 
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#if __STD_C
 
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static Sfdouble_t sfpow10(reg int n)
 
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#else
 
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static Sfdouble_t sfpow10(n)
 
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reg int n;
 
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#endif
 
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{
 
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        Sfdouble_t      dval;
 
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        switch(n)
 
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        {       case -3:        return .001;
 
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                case -2:        return .01;
 
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                case -1:        return .1;
 
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                case  0:        return 1.;
 
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                case  1:        return 10.;
 
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                case  2:        return 100.;
 
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                case  3:        return 1000.;
 
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        }
 
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        if(n < 0)
 
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        {       dval = .0001;
 
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                for(n += 4; n < 0; n += 1)
 
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                        dval /= 10.;
 
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        }
 
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        else
 
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        {       dval = 10000.;
 
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                for(n -= 4; n > 0; n -= 1)
 
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                        dval *= 10.;
 
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        }
 
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        return dval;
 
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}
 
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#if __STD_C
 
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Sfdouble_t _sfstrtod(reg const char* s, char** retp)
 
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#else
 
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Sfdouble_t _sfstrtod(s,retp)
 
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reg char*       s;      /* string to convert */
 
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char**          retp;   /* to return the remainder of string */
 
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#endif
 
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{
 
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        reg int         n, c, m;
 
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        reg int         mode, fexp, sign, expsign;
 
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        Sfdouble_t      dval;
 
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#if _lib_locale
 
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        int             decpoint = 0;
 
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        SFSETLOCALE(&decpoint,NIL(int*));
 
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#else
 
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#define decpoint        '.'
 
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#endif
 
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        /* skip initial blanks */
 
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        while(isspace(*s))
 
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                ++s;
 
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        /* get the sign */
 
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        if((sign = (*s == '-')) || *s == '+')
 
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                s += 1;
 
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        mode = IPART;
 
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        fexp = expsign = 0;
 
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        dval = 0.;
 
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        while(*s)
 
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        {       /* accumulate a handful of the digits */
 
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                for(m = BATCH, n = 0; m > 0; --m, ++s)
 
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                {       /* get and process a char */
 
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                        c = *s;
 
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                        if(isdigit(c))
 
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                                n = 10*n + (c - '0');
 
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                        else    break;
 
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                }
 
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                /* number of digits accumulated */
 
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                m = BATCH-m;
 
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                if(mode == IPART)
 
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                {       /* doing the integer part */
 
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                        if(dval == 0.)
 
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                                dval = (Sfdouble_t)n;
 
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                        else    dval = dval*sfpow10(m) + (Sfdouble_t)n;
 
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                }
 
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                else if(mode == FPART)
 
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                {       /* doing the fractional part */
 
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                        fexp -= m;
 
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                        if(n > 0)
 
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                                dval += n*sfpow10(fexp);
 
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                }
 
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                else if(n)
 
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                {       /* doing the exponent part */
 
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                        if(expsign)
 
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                                n = -n;
 
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                        dval *= sfpow10(n);
 
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                }
 
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                if(!c)
 
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                        break;
 
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                if(m < BATCH)
 
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                {       /* detected a non-digit */
 
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                        if(c == decpoint)
 
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                        {       /* start the fractional part or no match */
 
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                                if(mode != IPART)
 
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                                        break;
 
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                                mode = FPART;
 
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                                s += 1;
 
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                        }
 
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                        else if(c == 'e' || c == 'E')
 
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                        {       if(mode == EPART)
 
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                                        break;
 
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                                mode = EPART;
 
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                                c = *++s;
 
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                                if((expsign = (c == '-')) || c == '+')
 
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                                        s += 1;
 
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                        }
 
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                        else    break;
 
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                }
 
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        }
 
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        if(retp)
 
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                *retp = (char*)s;
 
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        return sign ? -dval : dval;
 
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}