getopt.c

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/*************************************************************************/
/*************************************************************************/


#include <GKlib.h>

/*************************************************************************/
/* Local function prototypes */
/*************************************************************************/
static void exchange (char **);
static char *gk_getopt_initialize (int, char **, char *);
static int gk_getopt_internal(int argc, char **argv, char *optstring, 
        struct gk_option *longopts, int *longind, int long_only);



/*************************************************************************/
/*************************************************************************/
char *gk_optarg;


/*************************************************************************/
/*************************************************************************/
int gk_optind = 1; 


/*************************************************************************/
/*************************************************************************/
int gk_opterr = 1;


/*************************************************************************/
/*************************************************************************/
int gk_optopt = '?';


/*************************************************************************/
/*
Records that the getopt facility has been initialized.
*/
/*************************************************************************/
int gk_getopt_initialized;


/*************************************************************************/
/*
The next char to be scanned in the option-element in which the last option 
character we returned was found.  This allows us to pick up the scan where 
we left off.

If this is zero, or a null string, it means resume the scan by advancing 
to the next ARGV-element.  
*/
/*************************************************************************/
static char *nextchar;


/*************************************************************************/
/*
Value of POSIXLY_CORRECT environment variable.  
*/
/*************************************************************************/
static char *posixly_correct;


/*************************************************************************/
/*
Describe how to deal with options that follow non-option ARGV-elements.

If the caller did not specify anything, the default is REQUIRE_ORDER if 
the environment variable POSIXLY_CORRECT is defined, PERMUTE otherwise.

REQUIRE_ORDER means don't recognize them as options; stop option processing 
when the first non-option is seen.  This is what Unix does.  This mode of 
operation is selected by either setting the environment variable 
POSIXLY_CORRECT, or using `+' as the first character of the list of 
option characters.

PERMUTE is the default.  We permute the contents of ARGV as we scan, so 
that eventually all the non-options are at the end.  This allows options
to be given in any order, even with programs that were not written to
expect this.

RETURN_IN_ORDER is an option available to programs that were written
to expect options and other ARGV-elements in any order and that care 
about the ordering of the two.  We describe each non-option ARGV-element
as if it were the argument of an option with character code 1.
Using `-' as the first character of the list of option characters
selects this mode of operation.

The special argument `--' forces an end of option-scanning regardless
of the value of `ordering'.  In the case of RETURN_IN_ORDER, only
`--' can cause `getopt' to return -1 with `gk_optind' != ARGC.  
*/
/*************************************************************************/
static enum
{
  REQUIRE_ORDER, PERMUTE, RETURN_IN_ORDER
} ordering;



/*************************************************************************/
/* 
Describe the part of ARGV that contains non-options that have
been skipped.  `first_nonopt' is the index in ARGV of the first of them;
`last_nonopt' is the index after the last of them.  
*/
/*************************************************************************/
static int first_nonopt;
static int last_nonopt;





/*************************************************************************/
/*
Handle permutation of arguments.  

Exchange two adjacent subsequences of ARGV. 
One subsequence is elements [first_nonopt,last_nonopt)
which contains all the non-options that have been skipped so far.
The other is elements [last_nonopt,gk_optind), which contains all
the options processed since those non-options were skipped.

`first_nonopt' and `last_nonopt' are relocated so that they describe
the new indices of the non-options in ARGV after they are moved.  
*/
/*************************************************************************/
static void exchange (char **argv)
{
  int bottom = first_nonopt;
  int middle = last_nonopt;
  int top = gk_optind;
  char *tem;

  /* Exchange the shorter segment with the far end of the longer segment.
     That puts the shorter segment into the right place.
     It leaves the longer segment in the right place overall,
     but it consists of two parts that need to be swapped next.  */

  while (top > middle && middle > bottom) {
    if (top - middle > middle - bottom) {
      /* Bottom segment is the short one.  */
      int len = middle - bottom;
      register int i;

      /* Swap it with the top part of the top segment.  */
      for (i = 0; i < len; i++) {
        tem = argv[bottom + i];
        argv[bottom + i] = argv[top - (middle - bottom) + i];
        argv[top - (middle - bottom) + i] = tem;
      }
      /* Exclude the moved bottom segment from further swapping.  */
      top -= len;
    }
    else {
      /* Top segment is the short one.  */
      int len = top - middle;
      register int i;

      /* Swap it with the bottom part of the bottom segment.  */
      for (i = 0; i < len; i++) {
        tem = argv[bottom + i];
        argv[bottom + i] = argv[middle + i];
        argv[middle + i] = tem;
      }
      /* Exclude the moved top segment from further swapping.  */
      bottom += len;
    }
  }

  /* Update records for the slots the non-options now occupy.  */

  first_nonopt += (gk_optind - last_nonopt);
  last_nonopt = gk_optind;
}



/*************************************************************************/
/*
Initialize the internal data when the first call is made.  
*/
/*************************************************************************/
static char *gk_getopt_initialize (int argc, char **argv, char *optstring)
{
  /* Start processing options with ARGV-element 1 (since ARGV-element 0
     is the program name); the sequence of previously skipped
     non-option ARGV-elements is empty.  */

  first_nonopt = last_nonopt = gk_optind;

  nextchar = NULL;

  posixly_correct = getenv("POSIXLY_CORRECT");

  /* Determine how to handle the ordering of options and nonoptions.  */
  if (optstring[0] == '-') {
    ordering = RETURN_IN_ORDER;
    ++optstring;
  }
  else if (optstring[0] == '+') {
    ordering = REQUIRE_ORDER;
    ++optstring;
  }
  else if (posixly_correct != NULL)
    ordering = REQUIRE_ORDER;
  else
    ordering = PERMUTE;

  return optstring;
}


/*************************************************************************/
/*
   Scan elements of ARGV (whose length is ARGC) for option characters
   given in OPTSTRING.

   If an element of ARGV starts with '-', and is not exactly "-" or "--",
   then it is an option element.  The characters of this element
   (aside from the initial '-') are option characters.  If `getopt'
   is called repeatedly, it returns successively each of the option characters
   from each of the option elements.

   If `getopt' finds another option character, it returns that character,
   updating `gk_optind' and `nextchar' so that the next call to `getopt' can
   resume the scan with the following option character or ARGV-element.

   If there are no more option characters, `getopt' returns -1.
   Then `gk_optind' is the index in ARGV of the first ARGV-element
   that is not an option.  (The ARGV-elements have been permuted
   so that those that are not options now come last.)

   OPTSTRING is a string containing the legitimate option characters.
   If an option character is seen that is not listed in OPTSTRING,
   return '?' after printing an error message.  If you set `gk_opterr' to
   zero, the error message is suppressed but we still return '?'.

   If a char in OPTSTRING is followed by a colon, that means it wants an arg,
   so the following text in the same ARGV-element, or the text of the following
   ARGV-element, is returned in `gk_optarg'.  Two colons mean an option that
   wants an optional arg; if there is text in the current ARGV-element,
   it is returned in `gk_optarg', otherwise `gk_optarg' is set to zero.

   If OPTSTRING starts with `-' or `+', it requests different methods of
   handling the non-option ARGV-elements.
   See the comments about RETURN_IN_ORDER and REQUIRE_ORDER, above.

   Long-named options begin with `--' instead of `-'.
   Their names may be abbreviated as long as the abbreviation is unique
   or is an exact match for some defined option.  If they have an
   argument, it follows the option name in the same ARGV-element, separated
   from the option name by a `=', or else the in next ARGV-element.
   When `getopt' finds a long-named option, it returns 0 if that option's
   `flag' field is nonzero, the value of the option's `val' field
   if the `flag' field is zero.

   LONGOPTS is a vector of `struct gk_option' terminated by an
   element containing a name which is zero.

   LONGIND returns the index in LONGOPT of the long-named option found.
   It is only valid when a long-named option has been found by the most
   recent call.

   If LONG_ONLY is nonzero, '-' as well as '--' can introduce
   long-named options.  
*/
/*************************************************************************/
static int gk_getopt_internal(int argc, char **argv, char *optstring, 
        struct gk_option *longopts, int *longind, int long_only)
{
  int print_errors = gk_opterr;
  if (optstring[0] == ':')
    print_errors = 0;

  if (argc < 1)
    return -1;

  gk_optarg = NULL;

  if (gk_optind == 0 || !gk_getopt_initialized) {
    if (gk_optind == 0)
      gk_optind = 1; /* Don't scan ARGV[0], the program name.  */
    optstring = gk_getopt_initialize(argc, argv, optstring);
    gk_getopt_initialized = 1;
  }

  /* Test whether ARGV[gk_optind] points to a non-option argument.
     Either it does not have option syntax, or there is an environment flag
     from the shell indicating it is not an option.  The later information
     is only used when the used in the GNU libc.  */
# define NONOPTION_P (argv[gk_optind][0] != '-' || argv[gk_optind][1] == '\0')

  if (nextchar == NULL || *nextchar == '\0') {
    /* Advance to the next ARGV-element.  */

    /* Give FIRST_NONOPT & LAST_NONOPT rational values if OPTIND has been
       moved back by the user (who may also have changed the arguments).  */
    if (last_nonopt > gk_optind)
      last_nonopt = gk_optind;
    if (first_nonopt > gk_optind)
      first_nonopt = gk_optind;

    if (ordering == PERMUTE) {
      /* If we have just processed some options following some non-options,
         exchange them so that the options come first.  */

      if (first_nonopt != last_nonopt && last_nonopt != gk_optind)
        exchange ((char **) argv);
      else if (last_nonopt != gk_optind)
        first_nonopt = gk_optind;

      /* Skip any additional non-options
         and extend the range of non-options previously skipped.  */

      while (gk_optind < argc && NONOPTION_P)
        gk_optind++;

      last_nonopt = gk_optind;
    }

    /* The special ARGV-element `--' means premature end of options.
       Skip it like a null option,
       then exchange with previous non-options as if it were an option,
       then skip everything else like a non-option.  */

    if (gk_optind != argc && !strcmp (argv[gk_optind], "--")) {
      gk_optind++;

      if (first_nonopt != last_nonopt && last_nonopt != gk_optind)
        exchange ((char **) argv);
      else if (first_nonopt == last_nonopt)
        first_nonopt = gk_optind;
      last_nonopt = argc;

      gk_optind = argc;
    }

    /* If we have done all the ARGV-elements, stop the scan
       and back over any non-options that we skipped and permuted.  */

    if (gk_optind == argc) {
      /* Set the next-arg-index to point at the non-options
         that we previously skipped, so the caller will digest them.  */
      if (first_nonopt != last_nonopt)
        gk_optind = first_nonopt;
      return -1;
    }

    /* If we have come to a non-option and did not permute it,
       either stop the scan or describe it to the caller and pass it by.  */

    if (NONOPTION_P) {
      if (ordering == REQUIRE_ORDER)
        return -1;
      gk_optarg = argv[gk_optind++];
      return 1;
    }

    /* We have found another option-ARGV-element.
       Skip the initial punctuation.  */

    nextchar = (argv[gk_optind] + 1 + (longopts != NULL && argv[gk_optind][1] == '-'));
  }

  /* Decode the current option-ARGV-element.  */

  /* Check whether the ARGV-element is a long option.

     If long_only and the ARGV-element has the form "-f", where f is
     a valid short option, don't consider it an abbreviated form of
     a long option that starts with f.  Otherwise there would be no
     way to give the -f short option.

     On the other hand, if there's a long option "fubar" and
     the ARGV-element is "-fu", do consider that an abbreviation of
     the long option, just like "--fu", and not "-f" with arg "u".

     This distinction seems to be the most useful approach.  */

  if (longopts != NULL && (argv[gk_optind][1] == '-' || (long_only && (argv[gk_optind][2] || !strchr(optstring, argv[gk_optind][1]))))) {
    char *nameend;
    struct gk_option *p;
    struct gk_option *pfound = NULL;
    int exact = 0;
    int ambig = 0;
    int indfound = -1;
    int option_index;

    for (nameend = nextchar; *nameend && *nameend != '='; nameend++)
      /* Do nothing.  */ ;

    /* Test all long options for either exact match or abbreviated matches.  */
    for (p = longopts, option_index = 0; p->name; p++, option_index++) {
      if (!strncmp (p->name, nextchar, nameend - nextchar)) {
        if ((unsigned int) (nameend - nextchar) == (unsigned int) strlen (p->name)) {
          /* Exact match found.  */
          pfound = p;
          indfound = option_index;
          exact = 1;
          break;
        }
        else if (pfound == NULL) {
          /* First nonexact match found.  */
          pfound = p;
          indfound = option_index;
        }
        else if (long_only || pfound->has_arg != p->has_arg || pfound->flag != p->flag || pfound->val != p->val)
          /* Second or later nonexact match found.  */
          ambig = 1;
      }
    }

    if (ambig && !exact) {
      if (print_errors)
        fprintf(stderr, "%s: option `%s' is ambiguous\n", argv[0], argv[gk_optind]);

      nextchar += strlen (nextchar);
      gk_optind++;
      gk_optopt = 0;
      return '?';
    }

    if (pfound != NULL) {
      option_index = indfound;
      gk_optind++;
      if (*nameend) {
        /* Don't test has_arg with >, because some C compilers don't allow it to be used on enums.  */
        if (pfound->has_arg)
          gk_optarg = nameend + 1;
        else {
          if (print_errors) {
            if (argv[gk_optind - 1][1] == '-')
              /* --option */
              fprintf(stderr, "%s: option `--%s' doesn't allow an argument\n", argv[0], pfound->name);
            else
              /* +option or -option */
              fprintf(stderr, "%s: option `%c%s' doesn't allow an argument\n", argv[0], argv[gk_optind - 1][0], pfound->name);
          }

          nextchar += strlen (nextchar);

          gk_optopt = pfound->val;
          return '?';
        }
      }
      else if (pfound->has_arg == 1) {
        if (gk_optind < argc)
          gk_optarg = argv[gk_optind++];
        else {
          if (print_errors)
            fprintf(stderr, "%s: option `%s' requires an argument\n", argv[0], argv[gk_optind - 1]);
          nextchar += strlen (nextchar);
          gk_optopt = pfound->val;
          return optstring[0] == ':' ? ':' : '?';
        }
      }
      nextchar += strlen (nextchar);
      if (longind != NULL)
        *longind = option_index;
      if (pfound->flag) {
        *(pfound->flag) = pfound->val;
        return 0;
      }
      return pfound->val;
    }

    /* Can't find it as a long option.  If this is not getopt_long_only,
       or the option starts with '--' or is not a valid short
        option, then it's an error. Otherwise interpret it as a short option.  */
    if (!long_only || argv[gk_optind][1] == '-' || strchr(optstring, *nextchar) == NULL) {
      if (print_errors) {
        if (argv[gk_optind][1] == '-')
          /* --option */
          fprintf(stderr, "%s: unrecognized option `--%s'\n", argv[0], nextchar);
        else
          /* +option or -option */
          fprintf(stderr, "%s: unrecognized option `%c%s'\n", argv[0], argv[gk_optind][0], nextchar);
      }
      nextchar = (char *) "";
      gk_optind++;
      gk_optopt = 0;
      return '?';
    }
  }

  /* Look at and handle the next short option-character.  */
  {
    char c = *nextchar++;
    char *temp = strchr(optstring, c);

    /* Increment `gk_optind' when we start to process its last character.  */
    if (*nextchar == '\0')
      ++gk_optind;

    if (temp == NULL || c == ':') {
      if (print_errors) {
        if (posixly_correct)
          /* 1003.2 specifies the format of this message.  */
          fprintf(stderr, "%s: illegal option -- %c\n", argv[0], c);
        else
          fprintf(stderr, "%s: invalid option -- %c\n", argv[0], c);
      }
      gk_optopt = c;
      return '?';
    }

    /* Convenience. Treat POSIX -W foo same as long option --foo */
    if (temp[0] == 'W' && temp[1] == ';') {
      char *nameend;
      struct gk_option *p;
      struct gk_option *pfound = NULL;
      int exact = 0;
      int ambig = 0;
      int indfound = 0;
      int option_index;

      /* This is an option that requires an argument.  */
      if (*nextchar != '\0') {
        gk_optarg = nextchar;
        /* If we end this ARGV-element by taking the rest as an arg,
           we must advance to the next element now.  */
        gk_optind++;
      }
      else if (gk_optind == argc) {
        if (print_errors) {
          /* 1003.2 specifies the format of this message.  */
          fprintf(stderr, "%s: option requires an argument -- %c\n", argv[0], c);
        }
        gk_optopt = c;
        if (optstring[0] == ':')
          c = ':';
        else
          c = '?';
        return c;
      }
      else
        /* We already incremented `gk_optind' once; increment it again when taking next ARGV-elt as argument.  */
        gk_optarg = argv[gk_optind++];

      /* gk_optarg is now the argument, see if it's in the table of longopts.  */

      for (nextchar = nameend = gk_optarg; *nameend && *nameend != '='; nameend++)
        /* Do nothing.  */ ;

      /* Test all long options for either exact match or abbreviated matches.  */
      for (p = longopts, option_index = 0; p->name; p++, option_index++) {
        if (!strncmp (p->name, nextchar, nameend - nextchar)) {
          if ((unsigned int) (nameend - nextchar) == strlen (p->name)) {
            /* Exact match found.  */
            pfound = p;
            indfound = option_index;
            exact = 1;
            break;
          }
          else if (pfound == NULL) {
            /* First nonexact match found.  */
            pfound = p;
            indfound = option_index;
          }
          else
            /* Second or later nonexact match found.  */
            ambig = 1;
        }
      }
      if (ambig && !exact) {
        if (print_errors)
          fprintf(stderr, "%s: option `-W %s' is ambiguous\n", argv[0], argv[gk_optind]);
        nextchar += strlen (nextchar);
        gk_optind++;
        return '?';
      }
      if (pfound != NULL) {
        option_index = indfound;
        if (*nameend) {
          /* Don't test has_arg with >, because some C compilers don't allow it to be used on enums.  */
          if (pfound->has_arg)
            gk_optarg = nameend + 1;
          else {
            if (print_errors)
              fprintf(stderr, "%s: option `-W %s' doesn't allow an argument\n", argv[0], pfound->name);

            nextchar += strlen (nextchar);
            return '?';
          }
        }
        else if (pfound->has_arg == 1) {
          if (gk_optind < argc)
            gk_optarg = argv[gk_optind++];
          else {
            if (print_errors)
              fprintf(stderr, "%s: option `%s' requires an argument\n", argv[0], argv[gk_optind - 1]);
            nextchar += strlen (nextchar);
            return optstring[0] == ':' ? ':' : '?';
          }
        }
        nextchar += strlen (nextchar);
        if (longind != NULL)
          *longind = option_index;
        if (pfound->flag) {
          *(pfound->flag) = pfound->val;
          return 0;
        }
        return pfound->val;
      }
      nextchar = NULL;
      return 'W';       /* Let the application handle it.   */
    }

    if (temp[1] == ':') {
      if (temp[2] == ':') {
        /* This is an option that accepts an argument optionally.  */
        if (*nextchar != '\0') {
          gk_optarg = nextchar;
          gk_optind++;
        } else {
          gk_optarg = NULL;
        }
        nextchar = NULL;
      } else {
        /* This is an option that requires an argument.  */
        if (*nextchar != '\0') {
          gk_optarg = nextchar;
          /* If we end this ARGV-element by taking the rest as an arg, we must
           * advance to the next element now.  */
          gk_optind++;
        } else if (gk_optind == argc) {
          if (print_errors) {
            /* 1003.2 specifies the format of this message.  */
            fprintf(stderr, "%s: option requires an argument -- %c\n", argv[0],
                    c);
          }
          gk_optopt = c;
          if (optstring[0] == ':')
            c = ':';
          else
            c = '?';
        } else {
          /* We already incremented `gk_optind' once; increment it again when
           * taking next ARGV-elt as argument.  */
          gk_optarg = argv[gk_optind++];
        }
        nextchar = NULL;
      }
    }
    return c;
  }
}



/*************************************************************************/
/*************************************************************************/
int gk_getopt(int argc, char **argv, char *options)
{
  return gk_getopt_internal(argc, argv, options, NULL, NULL, 0);
}


/*************************************************************************/
/*************************************************************************/
int gk_getopt_long( int argc, char **argv, char *options, 
       struct gk_option *long_options, int *opt_index)
{
  return gk_getopt_internal (argc, argv, options, long_options, opt_index, 0);
}



/*************************************************************************/
/*************************************************************************/
int gk_getopt_long_only(int argc, char **argv, char *options, 
       struct gk_option *long_options, int *opt_index)
{
  return gk_getopt_internal(argc, argv, options, long_options, opt_index, 1);
}