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, 2011  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 #include <unistd.h>
  33
  34 #include "lisp.h"
  35
  36 /* Since we use the macro CHAR_HEAD_P, we have to include this, but
  37    don't have to include others because CHAR_HEAD_P does not contains
  38    another macro.  */
  39 #include "character.h"
  40
  41 #ifndef DBL_MAX_10_EXP
  42 #define DBL_MAX_10_EXP 308 /* IEEE double */
  43 #endif
  44
  45 /* Generate output from a format-spec FORMAT,
  46    terminated at position FORMAT_END.
  47    Output goes in BUFFER, which has room for BUFSIZE chars.
  48    If the output does not fit, truncate it to fit.
  49    Returns the number of bytes stored into BUFFER.
  50    ARGS points to the vector of arguments, and NARGS says how many.
  51    A double counts as two arguments.
  52    String arguments are passed as C strings.
  53    Integers are passed as C integers.  */
  54
  55 EMACS_INT
  56 doprnt (char *buffer, register int bufsize, const char *format,
  57         const char *format_end, va_list ap)
  58 {
  59   const char *fmt = format;     /* Pointer into format string */
  60   register char *bufptr = buffer; /* Pointer into output buffer.. */
  61
  62   /* Use this for sprintf unless we need something really big.  */
  63   char tembuf[DBL_MAX_10_EXP + 100];
  64
  65   /* Size of sprintf_buffer.  */
  66   unsigned size_allocated = sizeof (tembuf);
  67
  68   /* Buffer to use for sprintf.  Either tembuf or same as BIG_BUFFER.  */
  69   char *sprintf_buffer = tembuf;
  70
  71   /* Buffer we have got with malloc.  */
  72   char *big_buffer = 0;
  73
  74   register int tem;
  75   unsigned char *string;
  76   char fixed_buffer[20];        /* Default buffer for small formatting. */
  77   char *fmtcpy;
  78   int minlen;
  79   unsigned char charbuf[MAX_MULTIBYTE_LENGTH + 1];      /* Used for %c.  */
  80
  81   if (format_end == 0)
  82     format_end = format + strlen (format);
  83
  84   if ((format_end - format + 1) < sizeof (fixed_buffer))
  85     fmtcpy = fixed_buffer;
  86   else
  87     fmtcpy = (char *) alloca (format_end - format + 1);
  88
  89   bufsize--;
  90
  91   /* Loop until end of format string or buffer full. */
  92   while (fmt != format_end && bufsize > 0)
  93     {
  94       if (*fmt == '%')  /* Check for a '%' character */
  95         {
  96           unsigned size_bound = 0;
  97           EMACS_INT width;  /* Columns occupied by STRING.  */
  98
  99           fmt++;
 100           /* Copy this one %-spec into fmtcpy.  */
 101           string = (unsigned char *) fmtcpy;
 102           *string++ = '%';
 103           while (1)
 104             {
 105               *string++ = *fmt;
 106               if ('0' <= *fmt && *fmt <= '9')
 107                 {
 108                   /* Get an idea of how much space we might need.
 109                      This might be a field width or a precision; e.g.
 110                      %1.1000f and %1000.1f both might need 1000+ bytes.
 111                      Parse the width or precision, checking for overflow.  */
 112                   unsigned n = *fmt - '0';
 113                   while ('0' <= fmt[1] && fmt[1] <= '9')
 114                     {
 115                       if (n * 10 + fmt[1] - '0' < n)
 116                         error ("Format width or precision too large");
 117                       n = n * 10 + fmt[1] - '0';
 118                       *string++ = *++fmt;
 119                     }
 120
 121                   if (size_bound < n)
 122                     size_bound = n;
 123                 }
 124               else if (*fmt == '-' || *fmt == ' ' || *fmt == '.' || *fmt == '+')
 125                 ;
 126               else
 127                 break;
 128               fmt++;
 129             }
 130           *string = 0;
 131
 132           /* Make the size bound large enough to handle floating point formats
 133              with large numbers.  */
 134           if (size_bound + DBL_MAX_10_EXP + 50 < size_bound)
 135             error ("Format width or precision too large");
 136           size_bound += DBL_MAX_10_EXP + 50;
 137
 138           /* Make sure we have that much.  */
 139           if (size_bound > size_allocated)
 140             {
 141               if (big_buffer)
 142                 big_buffer = (char *) xrealloc (big_buffer, size_bound);
 143               else
 144                 big_buffer = (char *) xmalloc (size_bound);
 145               sprintf_buffer = big_buffer;
 146               size_allocated = size_bound;
 147             }
 148           minlen = 0;
 149           switch (*fmt++)
 150             {
 151             default:
 152               error ("Invalid format operation %%%c", fmt[-1]);
 153
 154 /*          case 'b': */
 155             case 'd':
 156             case 'o':
 157             case 'x':
 158               if (sizeof (int) == sizeof (EMACS_INT))
 159                 ;
 160               else if (sizeof (long) == sizeof (EMACS_INT))
 161                 /* Insert an `l' the right place.  */
 162                 string[1] = string[0],
 163                 string[0] = string[-1],
 164                 string[-1] = 'l',
 165                 string++;
 166               else
 167                 abort ();
 168               sprintf (sprintf_buffer, fmtcpy, va_arg(ap, char *));
 169               /* Now copy into final output, truncating as nec.  */
 170               string = (unsigned char *) sprintf_buffer;
 171               goto doit;
 172
 173             case 'f':
 174             case 'e':
 175             case 'g':
 176               {
 177                 double d = va_arg(ap, double);
 178                 sprintf (sprintf_buffer, fmtcpy, d);
 179                 /* Now copy into final output, truncating as nec.  */
 180                 string = (unsigned char *) sprintf_buffer;
 181                 goto doit;
 182               }
 183
 184             case 'S':
 185               string[-1] = 's';
 186             case 's':
 187               if (fmtcpy[1] != 's')
 188                 minlen = atoi (&fmtcpy[1]);
 189               string = va_arg(ap, unsigned char *);
 190               tem = strlen (string);
 191               width = strwidth (string, tem);
 192               goto doit1;
 193
 194               /* Copy string into final output, truncating if no room.  */
 195             doit:
 196               /* Coming here means STRING contains ASCII only.  */
 197               width = tem = strlen (string);
 198             doit1:
 199               /* We have already calculated:
 200                  TEM -- length of STRING,
 201                  WIDTH -- columns occupied by STRING when displayed, and
 202                  MINLEN -- minimum columns of the output.  */
 203               if (minlen > 0)
 204                 {
 205                   while (minlen > width && bufsize > 0)
 206                     {
 207                       *bufptr++ = ' ';
 208                       bufsize--;
 209                       minlen--;
 210                     }
 211                   minlen = 0;
 212                 }
 213               if (tem > bufsize)
 214                 {
 215                   /* Truncate the string at character boundary.  */
 216                   tem = bufsize;
 217                   while (!CHAR_HEAD_P (string[tem - 1])) tem--;
 218                   memcpy (bufptr, string, tem);
 219                   /* We must calculate WIDTH again.  */
 220                   width = strwidth (bufptr, tem);
 221                 }
 222               else
 223                 memcpy (bufptr, string, tem);
 224               bufptr += tem;
 225               bufsize -= tem;
 226               if (minlen < 0)
 227                 {
 228                   while (minlen < - width && bufsize > 0)
 229                     {
 230                       *bufptr++ = ' ';
 231                       bufsize--;
 232                       minlen++;
 233                     }
 234                   minlen = 0;
 235                 }
 236               continue;
 237
 238             case 'c':
 239               {
 240                 /* Sometimes for %c we pass a char, which would widen
 241                    to int.  Sometimes we pass XFASTINT() or XINT()
 242                    values, which would be EMACS_INT.  Let's hope that
 243                    both are passed the same way, otherwise we'll need
 244                    to rewrite callers.  */
 245                 EMACS_INT chr = va_arg(ap, EMACS_INT);
 246                 tem = CHAR_STRING ((int) chr, charbuf);
 247                 string = charbuf;
 248                 string[tem] = 0;
 249                 width = strwidth (string, tem);
 250                 if (fmtcpy[1] != 'c')
 251                   minlen = atoi (&fmtcpy[1]);
 252                 goto doit1;
 253               }
 254
 255             case '%':
 256               fmt--;    /* Drop thru and this % will be treated as normal */
 257             }
 258         }
 259
 260       {
 261         /* Just some character; Copy it if the whole multi-byte form
 262            fit in the buffer.  */
 263         char *save_bufptr = bufptr;
 264
 265         do { *bufptr++ = *fmt++; }
 266         while (--bufsize > 0 && !CHAR_HEAD_P (*fmt));
 267         if (!CHAR_HEAD_P (*fmt))
 268           {
 269             bufptr = save_bufptr;
 270             break;
 271           }
 272       }
 273     };
 274
 275   /* If we had to malloc something, free it.  */
 276   xfree (big_buffer);
 277
 278   *bufptr = 0;          /* Make sure our string end with a '\0' */
 279   return bufptr - buffer;
 280 }
 281
 282 /* arch-tag: aa0ab528-7c5f-4c73-894c-aa2526a1efb3
 283    (do not change this comment) */