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, 2001-2011  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 3 of the License, or
  11 (at your option) 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.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21
  22 #include <config.h>
  23 #include <stdio.h>
  24 #include <ctype.h>
  25 #include <setjmp.h>
  26
  27 #ifdef STDC_HEADERS
  28 #include <float.h>
  29 #endif
  30
  31 #include <unistd.h>
  32
  33 #include "lisp.h"
  34
  35 /* Since we use the macro CHAR_HEAD_P, we have to include this, but
  36    don't have to include others because CHAR_HEAD_P does not contains
  37    another macro.  */
  38 #include "character.h"
  39
  40 #ifndef DBL_MAX_10_EXP
  41 #define DBL_MAX_10_EXP 308 /* IEEE double */
  42 #endif
  43
  44 /* Generate output from a format-spec FORMAT,
  45    terminated at position FORMAT_END.
  46    Output goes in BUFFER, which has room for BUFSIZE chars.
  47    If the output does not fit, truncate it to fit.
  48    Returns the number of bytes stored into BUFFER.
  49    ARGS points to the vector of arguments, and NARGS says how many.
  50    A double counts as two arguments.
  51    String arguments are passed as C strings.
  52    Integers are passed as C integers.  */
  53
  54 EMACS_INT
  55 doprnt (char *buffer, register int bufsize, const char *format,
  56         const char *format_end, va_list ap)
  57 {
  58   const char *fmt = format;     /* Pointer into format string */
  59   register char *bufptr = buffer; /* Pointer into output buffer.. */
  60
  61   /* Use this for sprintf unless we need something really big.  */
  62   char tembuf[DBL_MAX_10_EXP + 100];
  63
  64   /* Size of sprintf_buffer.  */
  65   unsigned size_allocated = sizeof (tembuf);
  66
  67   /* Buffer to use for sprintf.  Either tembuf or same as BIG_BUFFER.  */
  68   char *sprintf_buffer = tembuf;
  69
  70   /* Buffer we have got with malloc.  */
  71   char *big_buffer = 0;
  72
  73   register int tem;
  74   char *string;
  75   char fixed_buffer[20];        /* Default buffer for small formatting. */
  76   char *fmtcpy;
  77   int minlen;
  78   char charbuf[MAX_MULTIBYTE_LENGTH + 1];       /* Used for %c.  */
  79
  80   if (format_end == 0)
  81     format_end = format + strlen (format);
  82
  83   if ((format_end - format + 1) < sizeof (fixed_buffer))
  84     fmtcpy = fixed_buffer;
  85   else
  86     fmtcpy = (char *) alloca (format_end - format + 1);
  87
  88   bufsize--;
  89
  90   /* Loop until end of format string or buffer full. */
  91   while (fmt != format_end && bufsize > 0)
  92     {
  93       if (*fmt == '%')  /* Check for a '%' character */
  94         {
  95           unsigned size_bound = 0;
  96           EMACS_INT width;  /* Columns occupied by STRING.  */
  97
  98           fmt++;
  99           /* Copy this one %-spec into fmtcpy.  */
 100           string = fmtcpy;
 101           *string++ = '%';
 102           while (1)
 103             {
 104               *string++ = *fmt;
 105               if ('0' <= *fmt && *fmt <= '9')
 106                 {
 107                   /* Get an idea of how much space we might need.
 108                      This might be a field width or a precision; e.g.
 109                      %1.1000f and %1000.1f both might need 1000+ bytes.
 110                      Parse the width or precision, checking for overflow.  */
 111                   unsigned n = *fmt - '0';
 112                   while ('0' <= fmt[1] && fmt[1] <= '9')
 113                     {
 114                       if (n * 10 + fmt[1] - '0' < n)
 115                         error ("Format width or precision too large");
 116                       n = n * 10 + fmt[1] - '0';
 117                       *string++ = *++fmt;
 118                     }
 119
 120                   if (size_bound < n)
 121                     size_bound = n;
 122                 }
 123               else if (*fmt == '-' || *fmt == ' ' || *fmt == '.' || *fmt == '+')
 124                 ;
 125               else
 126                 break;
 127               fmt++;
 128             }
 129           *string = 0;
 130
 131           /* Make the size bound large enough to handle floating point formats
 132              with large numbers.  */
 133           if (size_bound + DBL_MAX_10_EXP + 50 < size_bound)
 134             error ("Format width or precision too large");
 135           size_bound += DBL_MAX_10_EXP + 50;
 136
 137           /* Make sure we have that much.  */
 138           if (size_bound > size_allocated)
 139             {
 140               if (big_buffer)
 141                 big_buffer = (char *) xrealloc (big_buffer, size_bound);
 142               else
 143                 big_buffer = (char *) xmalloc (size_bound);
 144               sprintf_buffer = big_buffer;
 145               size_allocated = size_bound;
 146             }
 147           minlen = 0;
 148           switch (*fmt++)
 149             {
 150             default:
 151               error ("Invalid format operation %%%c", fmt[-1]);
 152
 153 /*          case 'b': */
 154             case 'd':
 155             case 'o':
 156             case 'x':
 157               if (sizeof (int) == sizeof (EMACS_INT))
 158                 ;
 159               else if (sizeof (long) == sizeof (EMACS_INT))
 160                 /* Insert an `l' the right place.  */
 161                 string[1] = string[0],
 162                 string[0] = string[-1],
 163                 string[-1] = 'l',
 164                 string++;
 165               else
 166                 abort ();
 167               sprintf (sprintf_buffer, fmtcpy, va_arg(ap, char *));
 168               /* Now copy into final output, truncating as nec.  */
 169               string = sprintf_buffer;
 170               goto doit;
 171
 172             case 'f':
 173             case 'e':
 174             case 'g':
 175               {
 176                 double d = va_arg(ap, double);
 177                 sprintf (sprintf_buffer, fmtcpy, d);
 178                 /* Now copy into final output, truncating as nec.  */
 179                 string = sprintf_buffer;
 180                 goto doit;
 181               }
 182
 183             case 'S':
 184               string[-1] = 's';
 185             case 's':
 186               if (fmtcpy[1] != 's')
 187                 minlen = atoi (&fmtcpy[1]);
 188               string = va_arg (ap, char *);
 189               tem = strlen (string);
 190               width = strwidth (string, tem);
 191               goto doit1;
 192
 193               /* Copy string into final output, truncating if no room.  */
 194             doit:
 195               /* Coming here means STRING contains ASCII only.  */
 196               width = tem = strlen (string);
 197             doit1:
 198               /* We have already calculated:
 199                  TEM -- length of STRING,
 200                  WIDTH -- columns occupied by STRING when displayed, and
 201                  MINLEN -- minimum columns of the output.  */
 202               if (minlen > 0)
 203                 {
 204                   while (minlen > width && bufsize > 0)
 205                     {
 206                       *bufptr++ = ' ';
 207                       bufsize--;
 208                       minlen--;
 209                     }
 210                   minlen = 0;
 211                 }
 212               if (tem > bufsize)
 213                 {
 214                   /* Truncate the string at character boundary.  */
 215                   tem = bufsize;
 216                   while (!CHAR_HEAD_P (string[tem - 1])) tem--;
 217                   memcpy (bufptr, string, tem);
 218                   /* We must calculate WIDTH again.  */
 219                   width = strwidth (bufptr, tem);
 220                 }
 221               else
 222                 memcpy (bufptr, string, tem);
 223               bufptr += tem;
 224               bufsize -= tem;
 225               if (minlen < 0)
 226                 {
 227                   while (minlen < - width && bufsize > 0)
 228                     {
 229                       *bufptr++ = ' ';
 230                       bufsize--;
 231                       minlen++;
 232                     }
 233                   minlen = 0;
 234                 }
 235               continue;
 236
 237             case 'c':
 238               {
 239                 /* Sometimes for %c we pass a char, which would widen
 240                    to int.  Sometimes we pass XFASTINT() or XINT()
 241                    values, which would be EMACS_INT.  Let's hope that
 242                    both are passed the same way, otherwise we'll need
 243                    to rewrite callers.  */
 244                 EMACS_INT chr = va_arg(ap, EMACS_INT);
 245                 tem = CHAR_STRING ((int) chr, (unsigned char *) charbuf);
 246                 string = charbuf;
 247                 string[tem] = 0;
 248                 width = strwidth (string, tem);
 249                 if (fmtcpy[1] != 'c')
 250                   minlen = atoi (&fmtcpy[1]);
 251                 goto doit1;
 252               }
 253
 254             case '%':
 255               fmt--;    /* Drop thru and this % will be treated as normal */
 256             }
 257         }
 258
 259       {
 260         /* Just some character; Copy it if the whole multi-byte form
 261            fit in the buffer.  */
 262         char *save_bufptr = bufptr;
 263
 264         do { *bufptr++ = *fmt++; }
 265         while (--bufsize > 0 && !CHAR_HEAD_P (*fmt));
 266         if (!CHAR_HEAD_P (*fmt))
 267           {
 268             bufptr = save_bufptr;
 269             break;
 270           }
 271       }
 272     };
 273
 274   /* If we had to malloc something, free it.  */
 275   xfree (big_buffer);
 276
 277   *bufptr = 0;          /* Make sure our string end with a '\0' */
 278   return bufptr - buffer;
 279 }