libiberty/argv.c

   1 /* Create and destroy argument vectors (argv's)
   2    Copyright (C) 1992, 2001 Free Software Foundation, Inc.
   3    Written by Fred Fish @ Cygnus Support
   4
   5 This file is part of the libiberty library.
   6 Libiberty is free software; you can redistribute it and/or
   7 modify it under the terms of the GNU Library General Public
   8 License as published by the Free Software Foundation; either
   9 version 2 of the License, or (at your option) any later version.
  10
  11 Libiberty is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 Library General Public License for more details.
  15
  16 You should have received a copy of the GNU Library General Public
  17 License along with libiberty; see the file COPYING.LIB.  If
  18 not, write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
  19 Boston, MA 02110-1301, USA.  */
  20
  21
  22 /*  Create and destroy argument vectors.  An argument vector is simply an
  23     array of string pointers, terminated by a NULL pointer. */
  24
  25 #ifdef HAVE_CONFIG_H
  26 #include "config.h"
  27 #endif
  28 #include "ansidecl.h"
  29 #include "libiberty.h"
  30
  31 #define ISBLANK(ch) ((ch) == ' ' || (ch) == '\t')
  32
  33 /*  Routines imported from standard C runtime libraries. */
  34
  35 #include <stddef.h>
  36 #include <string.h>
  37 #include <stdlib.h>
  38
  39 #ifndef NULL
  40 #define NULL 0
  41 #endif
  42
  43 #ifndef EOS
  44 #define EOS '\0'
  45 #endif
  46
  47 #define INITIAL_MAXARGC 8       /* Number of args + NULL in initial argv */
  48
  49
  50 /*
  51
  52 @deftypefn Extension char** dupargv (char **@var{vector})
  53
  54 Duplicate an argument vector.  Simply scans through @var{vector},
  55 duplicating each argument until the terminating @code{NULL} is found.
  56 Returns a pointer to the argument vector if successful.  Returns
  57 @code{NULL} if there is insufficient memory to complete building the
  58 argument vector.
  59
  60 @end deftypefn
  61
  62 */
  63
  64 char **
  65 dupargv (char **argv)
  66 {
  67   int argc;
  68   char **copy;
  69
  70   if (argv == NULL)
  71     return NULL;
  72
  73   /* the vector */
  74   for (argc = 0; argv[argc] != NULL; argc++);
  75   copy = (char **) malloc ((argc + 1) * sizeof (char *));
  76   if (copy == NULL)
  77     return NULL;
  78
  79   /* the strings */
  80   for (argc = 0; argv[argc] != NULL; argc++)
  81     {
  82       int len = strlen (argv[argc]);
  83       copy[argc] = (char *) malloc (len + 1);
  84       if (copy[argc] == NULL)
  85         {
  86           freeargv (copy);
  87           return NULL;
  88         }
  89       strcpy (copy[argc], argv[argc]);
  90     }
  91   copy[argc] = NULL;
  92   return copy;
  93 }
  94
  95 /*
  96
  97 @deftypefn Extension void freeargv (char **@var{vector})
  98
  99 Free an argument vector that was built using @code{buildargv}.  Simply
 100 scans through @var{vector}, freeing the memory for each argument until
 101 the terminating @code{NULL} is found, and then frees @var{vector}
 102 itself.
 103
 104 @end deftypefn
 105
 106 */
 107
 108 void freeargv (char **vector)
 109 {
 110   register char **scan;
 111
 112   if (vector != NULL)
 113     {
 114       for (scan = vector; *scan != NULL; scan++)
 115         {
 116           free (*scan);
 117         }
 118       free (vector);
 119     }
 120 }
 121
 122 /*
 123
 124 @deftypefn Extension char** buildargv (char *@var{sp})
 125
 126 Given a pointer to a string, parse the string extracting fields
 127 separated by whitespace and optionally enclosed within either single
 128 or double quotes (which are stripped off), and build a vector of
 129 pointers to copies of the string for each field.  The input string
 130 remains unchanged.  The last element of the vector is followed by a
 131 @code{NULL} element.
 132
 133 All of the memory for the pointer array and copies of the string
 134 is obtained from @code{malloc}.  All of the memory can be returned to the
 135 system with the single function call @code{freeargv}, which takes the
 136 returned result of @code{buildargv}, as it's argument.
 137
 138 Returns a pointer to the argument vector if successful.  Returns
 139 @code{NULL} if @var{sp} is @code{NULL} or if there is insufficient
 140 memory to complete building the argument vector.
 141
 142 If the input is a null string (as opposed to a @code{NULL} pointer),
 143 then buildarg returns an argument vector that has one arg, a null
 144 string.
 145
 146 @end deftypefn
 147
 148 The memory for the argv array is dynamically expanded as necessary.
 149
 150 In order to provide a working buffer for extracting arguments into,
 151 with appropriate stripping of quotes and translation of backslash
 152 sequences, we allocate a working buffer at least as long as the input
 153 string.  This ensures that we always have enough space in which to
 154 work, since the extracted arg is never larger than the input string.
 155
 156 The argument vector is always kept terminated with a @code{NULL} arg
 157 pointer, so it can be passed to @code{freeargv} at any time, or
 158 returned, as appropriate.
 159
 160 */
 161
 162 char **buildargv (const char *input)
 163 {
 164   char *arg;
 165   char *copybuf;
 166   int squote = 0;
 167   int dquote = 0;
 168   int bsquote = 0;
 169   int argc = 0;
 170   int maxargc = 0;
 171   char **argv = NULL;
 172   char **nargv;
 173
 174   if (input != NULL)
 175     {
 176       copybuf = (char *) alloca (strlen (input) + 1);
 177       /* Is a do{}while to always execute the loop once.  Always return an
 178          argv, even for null strings.  See NOTES above, test case below. */
 179       do
 180         {
 181           /* Pick off argv[argc] */
 182           while (ISBLANK (*input))
 183             {
 184               input++;
 185             }
 186           if ((maxargc == 0) || (argc >= (maxargc - 1)))
 187             {
 188               /* argv needs initialization, or expansion */
 189               if (argv == NULL)
 190                 {
 191                   maxargc = INITIAL_MAXARGC;
 192                   nargv = (char **) malloc (maxargc * sizeof (char *));
 193                 }
 194               else
 195                 {
 196                   maxargc *= 2;
 197                   nargv = (char **) realloc (argv, maxargc * sizeof (char *));
 198                 }
 199               if (nargv == NULL)
 200                 {
 201                   if (argv != NULL)
 202                     {
 203                       freeargv (argv);
 204                       argv = NULL;
 205                     }
 206                   break;
 207                 }
 208               argv = nargv;
 209               argv[argc] = NULL;
 210             }
 211           /* Begin scanning arg */
 212           arg = copybuf;
 213           while (*input != EOS)
 214             {
 215               if (ISBLANK (*input) && !squote && !dquote && !bsquote)
 216                 {
 217                   break;
 218                 }
 219               else
 220                 {
 221                   if (bsquote)
 222                     {
 223                       bsquote = 0;
 224                       *arg++ = *input;
 225                     }
 226                   else if (*input == '\\')
 227                     {
 228                       bsquote = 1;
 229                     }
 230                   else if (squote)
 231                     {
 232                       if (*input == '\'')
 233                         {
 234                           squote = 0;
 235                         }
 236                       else
 237                         {
 238                           *arg++ = *input;
 239                         }
 240                     }
 241                   else if (dquote)
 242                     {
 243                       if (*input == '"')
 244                         {
 245                           dquote = 0;
 246                         }
 247                       else
 248                         {
 249                           *arg++ = *input;
 250                         }
 251                     }
 252                   else
 253                     {
 254                       if (*input == '\'')
 255                         {
 256                           squote = 1;
 257                         }
 258                       else if (*input == '"')
 259                         {
 260                           dquote = 1;
 261                         }
 262                       else
 263                         {
 264                           *arg++ = *input;
 265                         }
 266                     }
 267                   input++;
 268                 }
 269             }
 270           *arg = EOS;
 271           argv[argc] = strdup (copybuf);
 272           if (argv[argc] == NULL)
 273             {
 274               freeargv (argv);
 275               argv = NULL;
 276               break;
 277             }
 278           argc++;
 279           argv[argc] = NULL;
 280
 281           while (ISBLANK (*input))
 282             {
 283               input++;
 284             }
 285         }
 286       while (*input != EOS);
 287     }
 288   return (argv);
 289 }
 290
 291 #ifdef MAIN
 292
 293 /* Simple little test driver. */
 294
 295 static const char *const tests[] =
 296 {
 297   "a simple command line",
 298   "arg 'foo' is single quoted",
 299   "arg \"bar\" is double quoted",
 300   "arg \"foo bar\" has embedded whitespace",
 301   "arg 'Jack said \\'hi\\'' has single quotes",
 302   "arg 'Jack said \\\"hi\\\"' has double quotes",
 303   "a b c d e f g h i j k l m n o p q r s t u v w x y z 1 2 3 4 5 6 7 8 9",
 304
 305   /* This should be expanded into only one argument.  */
 306   "trailing-whitespace ",
 307
 308   "",
 309   NULL
 310 };
 311
 312 int
 313 main (void)
 314 {
 315   char **argv;
 316   const char *const *test;
 317   char **targs;
 318
 319   for (test = tests; *test != NULL; test++)
 320     {
 321       printf ("buildargv(\"%s\")\n", *test);
 322       if ((argv = buildargv (*test)) == NULL)
 323         {
 324           printf ("failed!\n\n");
 325         }
 326       else
 327         {
 328           for (targs = argv; *targs != NULL; targs++)
 329             {
 330               printf ("\t\"%s\"\n", *targs);
 331             }
 332           printf ("\n");
 333         }
 334       freeargv (argv);
 335     }
 336
 337   return 0;
 338 }
 339
 340 #endif  /* MAIN */