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