contrib/diffutils-2.8.1/lib/prepargs.c

   1 /* Parse arguments from a string and prepend them to an argv.
   2
   3    Copyright (C) 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 2, or (at your option)
   8    any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software
  17    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  18    02111-1307, USA.  */
  19
  20 /* Written by Paul Eggert <eggert@twinsun.com>.  */
  21
  22 #ifdef HAVE_CONFIG_H
  23 # include <config.h>
  24 #endif
  25 #include "prepargs.h"
  26 #include <string.h>
  27 #include <sys/types.h>
  28 #include <xalloc.h>
  29
  30 #include <ctype.h>
  31
  32 /* IN_CTYPE_DOMAIN (C) is nonzero if the unsigned char C can safely be given
  33    as an argument to <ctype.h> macros like "isspace".  */
  34 #ifdef STDC_HEADERS
  35 # define IN_CTYPE_DOMAIN(c) 1
  36 #else
  37 # define IN_CTYPE_DOMAIN(c) ((c) <= 0177)
  38 #endif
  39
  40 #define ISSPACE(c) (IN_CTYPE_DOMAIN (c) && isspace (c))
  41
  42 /* Find the white-space-separated options specified by OPTIONS, and
  43    using BUF to store copies of these options, set ARGV[0], ARGV[1],
  44    etc. to the option copies.  Return the number N of options found.
  45    Do not set ARGV[N].  If ARGV is zero, do not store ARGV[0] etc.
  46    Backslash can be used to escape whitespace (and backslashes).  */
  47 static int
  48 prepend_args (char const *options, char *buf, char **argv)
  49 {
  50   char const *o = options;
  51   char *b = buf;
  52   int n = 0;
  53
  54   for (;;)
  55     {
  56       while (ISSPACE ((unsigned char) *o))
  57         o++;
  58       if (!*o)
  59         return n;
  60       if (argv)
  61         argv[n] = b;
  62       n++;
  63
  64       do
  65         if ((*b++ = *o++) == '\\' && *o)
  66           b[-1] = *o++;
  67       while (*o && ! ISSPACE ((unsigned char) *o));
  68
  69       *b++ = '\0';
  70     }
  71 }
  72
  73 /* Prepend the whitespace-separated options in OPTIONS to the argument
  74    vector of a main program with argument count *PARGC and argument
  75    vector *PARGV.  */
  76 void
  77 prepend_default_options (char const *options, int *pargc, char ***pargv)
  78 {
  79   if (options)
  80     {
  81       char *buf = xmalloc (strlen (options) + 1);
  82       int prepended = prepend_args (options, buf, (char **) 0);
  83       int argc = *pargc;
  84       char * const *argv = *pargv;
  85       char **pp = (char **) xmalloc ((prepended + argc + 1) * sizeof *pp);
  86       *pargc = prepended + argc;
  87       *pargv = pp;
  88       *pp++ = *argv++;
  89       pp += prepend_args (options, buf, pp);
  90       while ((*pp++ = *argv++))
  91         continue;
  92     }
  93 }