diplodocus.org Git - nmh/blob - docs/historical/mh-jun-1982/Extras/libh/inputf.c

   1 #ifdef COMMENT
   2         Proprietary Rand Corporation, 1981.
   3         Further distribution of this software
   4         subject to the terms of the Rand
   5         license agreement.
   6 #endif
   7
   8 #
   9 /* inputf is roughly complementary to printf,
  10 except input comes from getchar (may be
  11 user supplied, must return 0 at eof). in addition
  12 all args must be pointers (addresses). the first arg
  13 is the format string.  '%' is used as the escape char as in
  14 printf.  the general format is %w.dc where w and d are decimal
  15 character counts, and c is one of (d, o, i, f, e, s, c, x).
  16 the args are all assumed to be pointers to the appropriate
  17 typed args -- note all floating point is assumed to be float
  18 unless the %e format is used (extended float). if w is omitted
  19 the field ends with the first field delimeter (typically, space, comma,
  20 and newline -- these can be specified by following the specification
  21 by a list of chars before the next '%'). d represents the default
  22 number of decimal places for 'f' and 'e' if no explicit
  23 decimal point.  for 's' w is the width of the field, and d is
  24 the maximum number of chars after stripping off delimeters
  25 on either end.  s and c are approximately identical, except
  26 that s returns a pointer into a static buffer, and c returns char
  27 by char into the program itself, which means a 'd' specification
  28 for c is essential, and in fact 1 is assumed as a default (as opposed
  29 to infinity for s). if a w field is specified, the input data
  30 is assumed to be in a fixed format, with exactly w columns
  31 devoted to the designated field.  this means that data in this format
  32 does not have to be separated by blanks, etc.  chars in the format
  33 string before the first '%' are output before any requests
  34 to the subroutine for chars.  e.g.:
  35         inputf("-> %i%e%s\n",&integ, &dbl, &charptr);
  36 would read an integer into integ, a double into dbl, and a string
  37 terminated only by a <nl> into a static buffer, returning its start
  38 addr in charptr, after prompting with "-> ". */
  39 #define DFTSEP ",; \t\n\r"      /* default field separators */
  40 #define NEXTCHR getchar()       /* character input routine */
  41 #define SCBLEN 100              /* max. no. of chars in static char buff */
  42 struct { float *fltp; };
  43 struct { double *dblp; };
  44 inputf(format,arg1,arg2,arg3)
  45 char *format;
  46 {
  47         register char *fp, *cp, cc;
  48         int **ap;
  49         int fld, val, wv, dv, radix;
  50         char formc, negflg, negexp, *fsp, *scp;
  51         static char scbuf[SCBLEN], fldsep[10];
  52         double dval;
  53
  54         ap = &arg1;
  55         fp = format;
  56         scp = scbuf;    /* init static string pointer */
  57
  58         while ((cc = *fp++) && cc != '%') putchar(cc);
  59         flush();
  60
  61         fld = 0;        /* used as return value when error found */
  62         while (cc) {
  63                 fld--;
  64                 wv = 0; dv = 0; /* init w.d fields */
  65                 while (numeric(cc = *fp++)) wv = wv*10 + cc - '0';
  66                 if (cc == '.')
  67                         while (numeric(cc = *fp++)) dv = dv*10 + cc - '0';
  68                 if (!wv) wv--; if (!dv) dv--;   /* zero --> minus one */
  69                 formc = cc;     /* save format character */
  70                 fsp = cp = fldsep;  /* collect terminators */
  71                 while (*cp++ = *fp)
  72                         if (*fp++ == '%') {
  73                                 fp--;
  74                                 *--cp = 0;
  75                                 break;
  76                         }
  77                 if (!*fsp) fsp = DFTSEP;
  78                 switch (formc) {
  79                 case 'o':
  80                         radix = 8;
  81                         goto ido;
  82                 case 'd':
  83                 case 'i':
  84                         radix = 10;
  85                 ido:
  86                         val = 0;
  87                         negflg = 0;
  88                         while ((cc = NEXTCHR) && (cc == ' ' || cc == '-') && --wv)
  89                                 if (cc == '-') negflg++;
  90                         if (!cc) return (fld);  /* return error if eof found */
  91                         if (formc == 'i' && cc == '0') radix = 8;
  92                         if (wv) do {
  93                                 if (numeric (cc)) {
  94                                         val = val*radix + cc - '0';
  95                                 } else if (any(cc,fsp))
  96                                         break;
  97                         } while (--wv && (cc = NEXTCHR));
  98                         if (negflg) val = -val;
  99                         **ap++ = val;
 100                         break;
 101                 case 'c':
 102                         if (dv < 0)
 103                                 if (wv < 0) dv = 1;
 104                                 else dv = wv;
 105                         cp = *ap++;
 106                         goto casecs;
 107                 case 's':
 108                         cp = scp;
 109                         val = scbuf + SCBLEN - 1 - cp;  /* calc max. limit on input */
 110                         if (dv<0 || dv>val)
 111                                 if ((dv = val) <= 0) return (fld);
 112                 casecs:
 113                         while ((cc = NEXTCHR) && cc == ' ' && --wv);
 114                         if (!cc) return (fld);  /* return error if eof found */
 115                         if (wv) do {
 116                                 if (any(cc,fsp)) break;
 117                                 if (!dv--) return (fld); /* too big */
 118                                 *cp++ = cc;
 119                         } while (--wv && (cc = NEXTCHR));
 120                         if (dv || formc == 's') *cp++ = 0;
 121                         if (formc == 'c') break;
 122                         **ap++ = scp;
 123                         scp = cp;
 124                         break;
 125                 case 'x':
 126                         while ((cc = NEXTCHR) && cc == ' ' && --wv);
 127                         if (wv)
 128                                 while (!any(cc,fsp) && --wv && (cc = NEXTCHR));
 129                         break;
 130                 case 'f':
 131                 case 'e':
 132                         dval = 0.;
 133                         negflg = 0;
 134                         val = 0;        /* used for explicit exponent */
 135                         radix = 0100000; /* used for decimal place count */
 136                         while ((cc = NEXTCHR) && (cc == ' ' || cc == '-') && --wv)
 137                                 if (cc == '-') negflg++;
 138                         if (!cc) return (fld);  /* return error if eof found */
 139                         if (wv) do {
 140                                 if (numeric(cc)) {
 141                                         dval = dval*10. + (cc-'0');
 142                                         radix++;
 143                                 } else if (cc == '.') {
 144                                         radix = 0;
 145                                         dv = -1;
 146                                 } else if (any(cc,fsp)) break;
 147                                 else if (cc == 'e') {
 148                                         negexp = 0;
 149                                         while ((cc = NEXTCHR) && !numeric(cc) && --wv)
 150                                                 if (cc == '-') negexp++;
 151                                         if (!cc) return (fld);  /* return error if eof found */
 152                                         if (wv) do {
 153                                                 if (numeric(cc))
 154                                                         val = val*10 + cc-'0';
 155                                                 else if (any(cc,fsp)) break;
 156                                         } while (--wv && (cc = NEXTCHR));
 157                                         if (negexp) val = -val;
 158                                         break;
 159                                 }
 160                         } while (--wv && (cc = NEXTCHR));
 161                         if (dv > 0) radix = dv;
 162                         if (radix > 0) val =- radix;
 163                         if (val >= 0)
 164                                 while (--val >= 0) dval = dval*10.;
 165                         else
 166                                 while (++val <= 0) dval = dval/10.;
 167                         if (negflg) dval = -dval;
 168                         if (formc == 'f')
 169                                 *ap->fltp = dval;
 170                         else
 171                                 *ap->dblp = dval;
 172                         ap++;
 173                         break;
 174                 default:
 175                         write(2,"bad format specification",20);
 176                         exit(fld);
 177                 }
 178                 cc = *fp++;
 179         }
 180         return (0);
 181 }
 182 numeric(chr)
 183 {
 184         return (chr >= '0' && chr <=