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, 2001, 2002, 2003, 2004, 2005,
   5                  2006, 2007, 2008, 2009, 2010  Free Software Foundation, Inc.
   6
   7 This file is part of GNU Emacs.
   8
   9 GNU Emacs is free software: you can redistribute it and/or modify
  10 it under the terms of the GNU General Public License as published by
  11 the Free Software Foundation, either version 3 of the License, or
  12 (at your option) any later version.
  13
  14 GNU Emacs is distributed in the hope that it will be useful,
  15 but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 GNU General Public License for more details.
  18
  19 You should have received a copy of the GNU General Public License
  20 along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
  21
  22
  23 #include <config.h>
  24 #include <stdio.h>
  25 #include <ctype.h>
  26 #include <setjmp.h>
  27
  28 #ifdef STDC_HEADERS
  29 #include <float.h>
  30 #endif
  31
  32 #ifdef HAVE_UNISTD_H
  33 #include <unistd.h>
  34 #endif
  35
  36 #ifdef HAVE_STDLIB_H
  37 #include <stdlib.h>
  38 #endif
  39
  40 #include "lisp.h"
  41
  42 #ifndef DBL_MAX_10_EXP
  43 #define DBL_MAX_10_EXP 308 /* IEEE double */
  44 #endif
  45
  46 /* Since we use the macro CHAR_HEAD_P, we have to include this, but
  47    don't have to include others because CHAR_HEAD_P does not contains
  48    another macro.  */
  49 #include "character.h"
  50
  51 /* Generate output from a format-spec FORMAT,
  52    terminated at position FORMAT_END.
  53    Output goes in BUFFER, which has room for BUFSIZE chars.
  54    If the output does not fit, truncate it to fit.
  55    Returns the number of bytes stored into BUFFER.
  56    ARGS points to the vector of arguments, and NARGS says how many.
  57    A double counts as two arguments.
  58    String arguments are passed as C strings.
  59    Integers are passed as C integers.  */
  60
  61 int
  62 doprnt (char *buffer, register int bufsize, const char *format,
  63         const char *format_end, va_list ap)
  64 {
  65   const char *fmt = format;     /* Pointer into format string */
  66   register char *bufptr = buffer; /* Pointer into output buffer.. */
  67
  68   /* Use this for sprintf unless we need something really big.  */
  69   char tembuf[DBL_MAX_10_EXP + 100];
  70
  71   /* Size of sprintf_buffer.  */
  72   unsigned size_allocated = sizeof (tembuf);
  73
  74   /* Buffer to use for sprintf.  Either tembuf or same as BIG_BUFFER.  */
  75   char *sprintf_buffer = tembuf;
  76
  77   /* Buffer we have got with malloc.  */
  78   char *big_buffer = 0;
  79
  80   register int tem;
  81   unsigned char *string;
  82   char fixed_buffer[20];        /* Default buffer for small formatting. */
  83   char *fmtcpy;
  84   int minlen;
  85   unsigned char charbuf[MAX_MULTIBYTE_LENGTH + 1];      /* Used for %c.  */
  86
  87   if (format_end == 0)
  88     format_end = format + strlen (format);
  89
  90   if ((format_end - format + 1) < sizeof (fixed_buffer))
  91     fmtcpy = fixed_buffer;
  92   else
  93     fmtcpy = (char *) alloca (format_end - format + 1);
  94
  95   bufsize--;
  96
  97   /* Loop until end of format string or buffer full. */
  98   while (fmt != format_end && bufsize > 0)
  99     {
 100       if (*fmt == '%')  /* Check for a '%' character */
 101         {
 102           unsigned size_bound = 0;
 103           int width;            /* Columns occupied by STRING.  */
 104
 105           fmt++;
 106           /* Copy this one %-spec into fmtcpy.  */
 107           string = (unsigned char *) fmtcpy;
 108           *string++ = '%';
 109           while (1)
 110             {
 111               *string++ = *fmt;
 112               if ('0' <= *fmt && *fmt <= '9')
 113                 {
 114                   /* Get an idea of how much space we might need.
 115                      This might be a field width or a precision; e.g.
 116                      %1.1000f and %1000.1f both might need 1000+ bytes.
 117                      Parse the width or precision, checking for overflow.  */
 118                   unsigned n = *fmt - '0';
 119                   while ('0' <= fmt[1] && fmt[1] <= '9')
 120                     {
 121                       if (n * 10 + fmt[1] - '0' < n)
 122                         error ("Format width or precision too large");
 123                       n = n * 10 + fmt[1] - '0';
 124                       *string++ = *++fmt;
 125                     }
 126
 127                   if (size_bound < n)
 128                     size_bound = n;
 129                 }
 130               else if (*fmt == '-' || *fmt == ' ' || *fmt == '.' || *fmt == '+')
 131                 ;
 132               else
 133                 break;
 134               fmt++;
 135             }
 136           *string = 0;
 137
 138           /* Make the size bound large enough to handle floating point formats
 139              with large numbers.  */
 140           if (size_bound + DBL_MAX_10_EXP + 50 < size_bound)
 141             error ("Format width or precision too large");
 142           size_bound += DBL_MAX_10_EXP + 50;
 143
 144           /* Make sure we have that much.  */
 145           if (size_bound > size_allocated)
 146             {
 147               if (big_buffer)
 148                 big_buffer = (char *) xrealloc (big_buffer, size_bound);
 149               else
 150                 big_buffer = (char *) xmalloc (size_bound);
 151               sprintf_buffer = big_buffer;
 152               size_allocated = size_bound;
 153             }
 154           minlen = 0;
 155           switch (*fmt++)
 156             {
 157             default:
 158               error ("Invalid format operation %%%c", fmt[-1]);
 159
 160 /*          case 'b': */
 161             case 'd':
 162             case 'o':
 163             case 'x':
 164               if (sizeof (int) == sizeof (EMACS_INT))
 165                 ;
 166               else if (sizeof (long) == sizeof (EMACS_INT))
 167                 /* Insert an `l' the right place.  */
 168                 string[1] = string[0],
 169                 string[0] = string[-1],
 170                 string[-1] = 'l',
 171                 string++;
 172               else
 173                 abort ();
 174               sprintf (sprintf_buffer, fmtcpy, va_arg(ap, char *));
 175               /* Now copy into final output, truncating as nec.  */
 176               string = (unsigned char *) sprintf_buffer;
 177               goto doit;
 178
 179             case 'f':
 180             case 'e':
 181             case 'g':
 182               {
 183                 double d = va_arg(ap, double);
 184                 sprintf (sprintf_buffer, fmtcpy, d);
 185                 /* Now copy into final output, truncating as nec.  */
 186                 string = (unsigned char *) sprintf_buffer;
 187                 goto doit;
 188               }
 189
 190             case 'S':
 191               string[-1] = 's';
 192             case 's':
 193               if (fmtcpy[1] != 's')
 194                 minlen = atoi (&fmtcpy[1]);
 195               string = va_arg(ap, unsigned char *);
 196               tem = strlen (string);
 197               width = strwidth (string, tem);
 198               goto doit1;
 199
 200               /* Copy string into final output, truncating if no room.  */
 201             doit:
 202               /* Coming here means STRING contains ASCII only.  */
 203               width = tem = strlen (string);
 204             doit1:
 205               /* We have already calculated:
 206                  TEM -- length of STRING,
 207                  WIDTH -- columns occupied by STRING when displayed, and
 208                  MINLEN -- minimum columns of the output.  */
 209               if (minlen > 0)
 210                 {
 211                   while (minlen > width && bufsize > 0)
 212                     {
 213                       *bufptr++ = ' ';
 214                       bufsize--;
 215                       minlen--;
 216                     }
 217                   minlen = 0;
 218                 }
 219               if (tem > bufsize)
 220                 {
 221                   /* Truncate the string at character boundary.  */
 222                   tem = bufsize;
 223                   while (!CHAR_HEAD_P (string[tem - 1])) tem--;
 224                   memcpy (bufptr, string, tem);
 225                   /* We must calculate WIDTH again.  */
 226                   width = strwidth (bufptr, tem);
 227                 }
 228               else
 229                 memcpy (bufptr, string, tem);
 230               bufptr += tem;
 231               bufsize -= tem;
 232               if (minlen < 0)
 233                 {
 234                   while (minlen < - width && bufsize > 0)
 235                     {
 236                       *bufptr++ = ' ';
 237                       bufsize--;
 238                       minlen++;
 239                     }
 240                   minlen = 0;
 241                 }
 242               continue;
 243
 244             case 'c':
 245               {
 246                 /* Sometimes for %c we pass a char, which would widen
 247                    to int.  Sometimes we pass XFASTINT() or XINT()
 248                    values, which would be EMACS_INT.  Let's hope that
 249                    both are passed the same way, otherwise we'll need
 250                    to rewrite callers.  */
 251                 EMACS_INT chr = va_arg(ap, EMACS_INT);
 252                 tem = CHAR_STRING ((int) chr, charbuf);
 253                 string = charbuf;
 254                 string[tem] = 0;
 255                 width = strwidth (string, tem);
 256                 if (fmtcpy[1] != 'c')
 257                   minlen = atoi (&fmtcpy[1]);
 258                 goto doit1;
 259               }
 260
 261             case '%':
 262               fmt--;    /* Drop thru and this % will be treated as normal */
 263             }
 264         }
 265
 266       {
 267         /* Just some character; Copy it if the whole multi-byte form
 268            fit in the buffer.  */
 269         char *save_bufptr = bufptr;
 270
 271         do { *bufptr++ = *fmt++; }
 272         while (--bufsize > 0 && !CHAR_HEAD_P (*fmt));
 273         if (!CHAR_HEAD_P (*fmt))
 274           {
 275             bufptr = save_bufptr;
 276             break;
 277           }
 278       }
 279     };
 280
 281   /* If we had to malloc something, free it.  */
 282   xfree (big_buffer);
 283
 284   *bufptr = 0;          /* Make sure our string end with a '\0' */
 285   return bufptr - buffer;
 286 }
 287
 288 /* arch-tag: aa0ab528-7c5f-4c73-894c-aa2526a1efb3
 289    (do not change this comment) */