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 <stdio.h>
  24 #include <ctype.h>
  25
  26 /* Generate output from a format-spec FORMAT,
  27    terminated at position FORMAT_END.
  28    Output goes in BUFFER, which has room for BUFSIZE chars.
  29    If the output does not fit, truncate it to fit.
  30    Returns the number of characters stored into BUFFER.
  31    ARGS points to the vector of arguments, and NARGS says how many.
  32    A double counts as two arguments.  */
  33
  34 doprnt (buffer, bufsize, format, format_end, nargs, args)
  35      char *buffer;
  36      register int bufsize;
  37      char *format;
  38      char *format_end;
  39      int nargs;
  40      char **args;
  41 {
  42   int cnt = 0;                  /* Number of arg to gobble next */
  43   register char *fmt = format;  /* Pointer into format string */
  44   register char *bufptr = buffer; /* Pointer into output buffer.. */
  45   /* Use this for sprintf unless we need something really big.  */
  46   char tembuf[100];
  47   /* Size of sprintf_buffer.  */
  48   int size_allocated = 100;
  49   /* Buffer to use for sprintf.  Either tembuf or same as BIG_BUFFER.  */
  50   char *sprintf_buffer = tembuf;
  51   /* Buffer we have got with malloc.  */
  52   char *big_buffer = 0;
  53   register int tem;
  54   char *string;
  55   char fmtcpy[20];
  56   int minlen;
  57   int size;                     /* Field width factor; e.g., %90d */
  58
  59   if (format_end == 0)
  60     format_end = format + strlen (format);
  61
  62   bufsize--;
  63   while (fmt != format_end && bufsize > 0)      /* Loop until end of format
  64                                                    string or buffer full */
  65     {
  66       if (*fmt == '%')  /* Check for a '%' character */
  67         {
  68           int size_bound;
  69
  70           fmt++;
  71           /* Copy this one %-spec into fmtcpy.  */
  72           string = fmtcpy;
  73           *string++ = '%';
  74           while (string < fmtcpy + sizeof fmtcpy - 1)
  75             {
  76               *string++ = *fmt;
  77               if (! (*fmt >= '0' && *fmt <= '9') && *fmt != '-' && *fmt != ' ')
  78                 break;
  79               fmt++;
  80             }
  81           *string = 0;
  82           /* Get an idea of how much space we might need.  */
  83           size_bound = atoi (&fmtcpy[1]) + 50;
  84           /* Make sure we have that much.  */
  85           if (size_bound > size_allocated)
  86             {
  87               if (big_buffer)
  88                 big_buffer = (char *) xrealloc (big_buffer, size_bound);
  89               else
  90                 big_buffer = (char *) xmalloc (size_bound);
  91               sprintf_buffer = big_buffer;
  92               size_allocated = size_bound;
  93             }
  94           minlen = 0;
  95           switch (*fmt++)
  96             {
  97             default:
  98               error ("Invalid format operation %%%c", fmt[-1]);
  99
 100 /*          case 'b': */
 101             case 'd':
 102             case 'o':
 103             case 'x':
 104               if (cnt == nargs)
 105                 error ("Format string wants too many arguments");
 106               sprintf (sprintf_buffer, fmtcpy, args[cnt++]);
 107               /* Now copy into final output, truncating as nec.  */
 108               string = sprintf_buffer;
 109               goto doit;
 110
 111             case 'f':
 112             case 'e':
 113             case 'g':
 114               {
 115                 union { double d; char *half[2]; } u;
 116                 if (cnt + 1 == nargs)
 117                   error ("Format string wants too many arguments");
 118                 u.half[0] = args[cnt++];
 119                 u.half[1] = args[cnt++];
 120                 sprintf (sprintf_buffer, fmtcpy, u.d);
 121                 /* Now copy into final output, truncating as nec.  */
 122                 string = sprintf_buffer;
 123                 goto doit;
 124               }
 125
 126             case 'S':
 127               string[-1] = 's';
 128             case 's':
 129               if (cnt == nargs)
 130                 error ("Format string wants too many arguments");
 131               string = args[cnt++];
 132               if (fmtcpy[1] != 's')
 133                 minlen = atoi (&fmtcpy[1]);
 134               /* Copy string into final output, truncating if no room.  */
 135             doit:
 136               tem = strlen (string);
 137               if (minlen > 0)
 138                 {
 139                   while (minlen > tem && bufsize > 0)
 140                     {
 141                       *bufptr++ = ' ';
 142                       bufsize--;
 143                       minlen--;
 144                     }
 145                   minlen = 0;
 146                 }
 147               if (tem > bufsize)
 148                 tem = bufsize;
 149               strncpy (bufptr, string, tem);
 150               bufptr += tem;
 151               bufsize -= tem;
 152               if (minlen < 0)
 153                 {
 154                   while (minlen < - tem && bufsize > 0)
 155                     {
 156                       *bufptr++ = ' ';
 157                       bufsize--;
 158                       minlen++;
 159                     }
 160                   minlen = 0;
 161                 }
 162               continue;
 163
 164             case 'c':
 165               if (cnt == nargs)
 166                 error ("Format string wants too many arguments");
 167               *bufptr++ = (int) args[cnt++];
 168               bufsize--;
 169               continue;
 170
 171             case '%':
 172               fmt--;    /* Drop thru and this % will be treated as normal */
 173             }
 174         }
 175       *bufptr++ = *fmt++;       /* Just some characters; Copy 'em */
 176       bufsize--;
 177     };
 178
 179   /* If we had to malloc something, free it.  */
 180   if (big_buffer)
 181     xfree (big_buffer);
 182
 183   *bufptr = 0;          /* Make sure our string end with a '\0' */
 184   return bufptr - buffer;
 185 }