src/doprnt.c

   1 /* Output like sprintf to a buffer of specified size.
   2    Also takes args differently: pass one pointer to an array of strings
   3    in addition to the format string which is separate.
   4    Copyright (C) 1985 Free Software Foundation, Inc.
   5
   6 This file is part of GNU Emacs.
   7
   8 GNU Emacs is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 1, or (at your option)
  11 any later version.
  12
  13 GNU Emacs is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GNU Emacs; see the file COPYING.  If not, write to
  20 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  21
  22
  23 #include <config.h>
  24 #include <stdio.h>
  25 #include <ctype.h>
  26
  27 /* Generate output from a format-spec FORMAT,
  28    terminated at position FORMAT_END.
  29    Output goes in BUFFER, which has room for BUFSIZE chars.
  30    If the output does not fit, truncate it to fit.
  31    Returns the number of characters stored into BUFFER.
  32    ARGS points to the vector of arguments, and NARGS says how many.
  33    A double counts as two arguments.  */
  34
  35 doprnt (buffer, bufsize, format, format_end, nargs, args)
  36      char *buffer;
  37      register int bufsize;
  38      char *format;
  39      char *format_end;
  40      int nargs;
  41      char **args;
  42 {
  43   int cnt = 0;                  /* Number of arg to gobble next */
  44   register char *fmt = format;  /* Pointer into format string */
  45   register char *bufptr = buffer; /* Pointer into output buffer.. */
  46
  47   /* Use this for sprintf unless we need something really big.  */
  48   char tembuf[100];
  49
  50   /* Size of sprintf_buffer.  */
  51   int size_allocated = 100;
  52
  53   /* Buffer to use for sprintf.  Either tembuf or same as BIG_BUFFER.  */
  54   char *sprintf_buffer = tembuf;
  55
  56   /* Buffer we have got with malloc.  */
  57   char *big_buffer = 0;
  58
  59   register int tem;
  60   char *string;
  61   char fixed_buffer[20];        /* Default buffer for small formatting. */
  62   char *fmtcpy;
  63   int minlen;
  64   int size;                     /* Field width factor; e.g., %90d */
  65   char charbuf[2];              /* Used for %c.  */
  66
  67   if (format_end == 0)
  68     format_end = format + strlen (format);
  69
  70   if ((format_end - format + 1) < sizeof (fixed_buffer))
  71     fmtcpy = fixed_buffer;
  72   else
  73     fmtcpy = (char *) alloca (format_end - format + 1);
  74
  75   bufsize--;
  76
  77   /* Loop until end of format string or buffer full. */
  78   while (fmt != format_end && bufsize > 0)
  79     {
  80       if (*fmt == '%')  /* Check for a '%' character */
  81         {
  82           int size_bound;
  83
  84           fmt++;
  85           /* Copy this one %-spec into fmtcpy.  */
  86           string = fmtcpy;
  87           *string++ = '%';
  88           while (1)
  89             {
  90               *string++ = *fmt;
  91               if (! (*fmt >= '0' && *fmt <= '9')
  92                   && *fmt != '-' && *fmt != ' '&& *fmt != '.')
  93                 break;
  94               fmt++;
  95             }
  96           *string = 0;
  97           /* Get an idea of how much space we might need.  */
  98           size_bound = atoi (&fmtcpy[1]);
  99
 100           /* Avoid pitfall of negative "size" parameter ("%-200d"). */
 101           if (size_bound < 0)
 102             size_bound = -size_bound;
 103           size_bound += 50;
 104
 105           /* Make sure we have that much.  */
 106           if (size_bound > size_allocated)
 107             {
 108               if (big_buffer)
 109                 big_buffer = (char *) xrealloc (big_buffer, size_bound);
 110               else
 111                 big_buffer = (char *) xmalloc (size_bound);
 112               sprintf_buffer = big_buffer;
 113               size_allocated = size_bound;
 114             }
 115           minlen = 0;
 116           switch (*fmt++)
 117             {
 118             default:
 119               error ("Invalid format operation %%%c", fmt[-1]);
 120
 121 /*          case 'b': */
 122             case 'd':
 123             case 'o':
 124             case 'x':
 125               if (cnt == nargs)
 126                 error ("not enough arguments for format string");
 127               sprintf (sprintf_buffer, fmtcpy, args[cnt++]);
 128               /* Now copy into final output, truncating as nec.  */
 129               string = sprintf_buffer;
 130               goto doit;
 131
 132             case 'f':
 133             case 'e':
 134             case 'g':
 135               {
 136                 union { double d; char *half[2]; } u;
 137                 if (cnt + 1 == nargs)
 138                   error ("not enough arguments for format string");
 139                 u.half[0] = args[cnt++];
 140                 u.half[1] = args[cnt++];
 141                 sprintf (sprintf_buffer, fmtcpy, u.d);
 142                 /* Now copy into final output, truncating as nec.  */
 143                 string = sprintf_buffer;
 144                 goto doit;
 145               }
 146
 147             case 'S':
 148               string[-1] = 's';
 149             case 's':
 150               if (cnt == nargs)
 151                 error ("not enough arguments for format string");
 152               string = args[cnt++];
 153               if (fmtcpy[1] != 's')
 154                 minlen = atoi (&fmtcpy[1]);
 155               /* Copy string into final output, truncating if no room.  */
 156             doit:
 157               tem = strlen (string);
 158             doit1:
 159               if (minlen > 0)
 160                 {
 161                   while (minlen > tem && bufsize > 0)
 162                     {
 163                       *bufptr++ = ' ';
 164                       bufsize--;
 165                       minlen--;
 166                     }
 167                   minlen = 0;
 168                 }
 169               if (tem > bufsize)
 170                 tem = bufsize;
 171               strncpy (bufptr, string, tem);
 172               bufptr += tem;
 173               bufsize -= tem;
 174               if (minlen < 0)
 175                 {
 176                   while (minlen < - tem && bufsize > 0)
 177                     {
 178                       *bufptr++ = ' ';
 179                       bufsize--;
 180                       minlen++;
 181                     }
 182                   minlen = 0;
 183                 }
 184               continue;
 185
 186             case 'c':
 187               if (cnt == nargs)
 188                 error ("not enough arguments for format string");
 189               *charbuf = (int) args[cnt++];
 190               string = charbuf;
 191               tem = 1;
 192               if (fmtcpy[1] != 'c')
 193                 minlen = atoi (&fmtcpy[1]);
 194               goto doit1;
 195
 196             case '%':
 197               fmt--;    /* Drop thru and this % will be treated as normal */
 198             }
 199         }
 200       *bufptr++ = *fmt++;       /* Just some characters; Copy 'em */
 201       bufsize--;
 202     };
 203
 204   /* If we had to malloc something, free it.  */
 205   if (big_buffer)
 206     xfree (big_buffer);
 207
 208   *bufptr = 0;          /* Make sure our string end with a '\0' */
 209   return bufptr - buffer;
 210 }