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range.c

/* range.c
 * Range routines
 *
 * $Id: range.c 28145 2009-04-24 12:18:31Z wmeier $
 *
 * Dick Gooris <gooris@lucent.com>
 * Ulf Lamping <ulf.lamping@web.de>
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <string.h>
#include <ctype.h>
#include <errno.h>

#include <glib.h>

#include <epan/frame_data.h>

#include <epan/range.h>
#include <epan/emem.h>
#include <stdio.h>

/*
 * Size of the header of a range_t.
 */
#define RANGE_HDR_SIZE (sizeof (range_t) - sizeof (range_admin_t))

/* Allocate an empty range. */
range_t *range_empty(void)
{
   range_t *range;

   range = g_malloc(RANGE_HDR_SIZE);
   range->nranges = 0;
   return range;
}

/******************** Range Entry Parser *********************************/

/* Converts a range string to a fast comparable array of ranges.
 * The parameter 'es' points to the string to be converted.
 * The parameter 'max_value' specifies the maximum value in a
 * range.
 *
 * This function allocates a range_t large enough to hold the number
 * of ranges specified, and fills the array range->ranges containing
 * low and high values with the number of ranges being range->nranges.
 * After having called this function, the function value_is_in_range()
 * determines whether a given number is within the range or not. 
 *
 * In case of a single number, we make a range where low is equal to high. 
 * We take care on wrongly entered ranges; opposite order will be taken
 * care of.
 * 
 * The following syntax is accepted :
 *
 *   1-20,30-40     Range from 1 to 20, and packets 30 to 40
 *   -20,30         Range from 1 to 20, and packet 30
 *   20,30,40-      20, 30, and the range from 40 to the end
 *   20-10,30-25    Range from 10 to 20, and from 25 to 30
 *   -              All values
 */

convert_ret_t range_convert_str(range_t **rangep, const gchar *es,
                        guint32 max_value)
{
   range_t       *range;
   guint         nranges;
   const gchar   *p;
   char          *endp;
   gchar         c;
   guint         i;
   guint32       tmp;
   unsigned long val;

   /* Allocate a range; this has room for one subrange. */
   range = g_malloc(RANGE_HDR_SIZE + sizeof (range_admin_t));
   range->nranges = 0;
   nranges = 1;

   /* Process the ranges separately until we get a comma or end of string.
    *
    * We build a structure array called ranges of high and low values. After the
    * following loop, we have the nranges variable which tells how many ranges
    * were found. The number of individual ranges is limited to 'MaxRanges'
    */

   p = es;
   for (;;) {
      /* Skip white space. */
      while ((c = *p) == ' ' || c == '\t')
       p++;
      if (c == '\0')
       break;

      /* This must be a subrange.  Make sure we have room for it. */
      if (range->nranges >= nranges) {
       /* Grow the structure.
        * 4 is an arbitrarily chosen number.
        * We start with 1, under the assumption that people
        * will often give a single number or range, and then
        * proceed to keep it a multiple of 4.
        */
       if (nranges == 1)
          nranges = 4;
       else
          nranges += 4;
       range = g_realloc(range, RANGE_HDR_SIZE +
                     nranges*sizeof (range_admin_t));
      }

      if (c == '-') {
       /* Subrange starts with 1. */
       range->ranges[range->nranges].low = 1;
      } else if (isdigit((unsigned char)c)) {
       /* Subrange starts with the specified number */
       errno = 0;
       val = strtoul(p, &endp, 10);
       if (p == endp) {
          /* That wasn't a valid number. */
          g_free(range);
          return CVT_SYNTAX_ERROR;
       }
       if (errno == ERANGE || val > G_MAXUINT32) {
          /* That was valid, but it's too big. */
          g_free(range);
          return CVT_NUMBER_TOO_BIG;
       } 
       p = endp;
       range->ranges[range->nranges].low = val;

       /* Skip white space. */
       while ((c = *p) == ' ' || c == '\t')
          p++;
      } else {
       /* Neither empty nor a number. */
       g_free(range);
       return CVT_SYNTAX_ERROR;
      }

      if (c == '-') {
       /* There's a hyphen in the range.  Skip past it. */
       p++;

       /* Skip white space. */
       while ((c = *p) == ' ' || c == '\t')
          p++;

       if (c == ',' || c == '\0') {
         /* End of subrange string; that means the subrange ends
          * with max_value.
          */
         range->ranges[range->nranges].high = max_value;
       } else if (isdigit((unsigned char)c)) {
          /* Subrange ends with the specified number. */
          errno = 0;
          val = strtoul(p, &endp, 10);
          if (p == endp) {
             /* That wasn't a valid number. */
             g_free(range);
             return CVT_SYNTAX_ERROR;
          }
          if (errno == ERANGE || val > G_MAXUINT32) {
             /* That was valid, but it's too big. */
             g_free(range);
             return CVT_NUMBER_TOO_BIG;
          } 
          p = endp;
          range->ranges[range->nranges].high = val;

          /* Skip white space. */
          while ((c = *p) == ' ' || c == '\t')
             p++;
       } else {
          /* Neither empty nor a number. */
          g_free(range);
          return CVT_SYNTAX_ERROR;
       }
      } else if (c == ',' || c == '\0') {
       /* End of subrange string; that means there's no hyphen
        * in the subrange, so the start and the end are the same.
        */
       range->ranges[range->nranges].high = range->ranges[range->nranges].low;
      } else {
       /* Invalid character. */ 
       g_free(range);
       return CVT_SYNTAX_ERROR;
      }
      range->nranges++;

      if (c == ',') {
       /* Subrange is followed by a comma; skip it. */
       p++;
      }
   }

   /* Now we are going through the low and high values, and check
    * whether they are in a proper order. Low should be equal or lower
    * than high. So, go through the loop and swap if needed.
    */
   for (i=0; i < range->nranges; i++) {
      if (range->ranges[i].low > range->ranges[i].high) {
       tmp = range->ranges[i].low;
       range->ranges[i].low  = range->ranges[i].high;
       range->ranges[i].high = tmp;
      }
   }

   /* In case we want to know what the result ranges are :
    *
    * for (i=0; i < range->nranges; i++) {
    *  printf("Function : range_convert_str L=%u \t H=%u\n",range->ranges[i].low,range->ranges[i].high);
    * }
    *
    */
   *rangep = range;
   return CVT_NO_ERROR;
} /* range_convert_str */

/* This function returns TRUE if a given value is within one of the ranges
 * stored in the ranges array.
 */
gboolean value_is_in_range(range_t *range, guint32 val)
{
   guint i;

   if (range) {
      for (i=0; i < range->nranges; i++) {
         if (val >= range->ranges[i].low && val <= range->ranges[i].high)
           return TRUE;
      }
   }
   return(FALSE);
}

/* This function returns TRUE if the two given range_t's are equal.
 */
gboolean ranges_are_equal(range_t *a, range_t *b)
{
   guint i;

   if (a->nranges != b->nranges)
      return FALSE;

   for (i=0; i < a->nranges; i++) {
      if (a->ranges[i].low != b->ranges[i].low)
       return FALSE;

      if (a->ranges[i].high != b->ranges[i].high)
       return FALSE;
   }

   return TRUE;

}

/* This function calls the provided callback function for each value in
 * in the range.
 */
void
range_foreach(range_t *range, void (*callback)(guint32 val))
{
   guint32 i, j;

   for (i=0; i < range->nranges; i++) {
      for (j = range->ranges[i].low; j <= range->ranges[i].high; j++)
       callback(j);
   }
}

/* This function converts a range_t to a (ep_alloc()-allocated) string.  */
char *
range_convert_range(range_t *range)
{
   guint32 i;
   gboolean prepend_comma = FALSE;
   emem_strbuf_t *strbuf;

   strbuf=ep_strbuf_new(NULL);

   for (i=0; i < range->nranges; i++) {
      if (range->ranges[i].low == range->ranges[i].high) {
       ep_strbuf_append_printf(strbuf, "%s%u", prepend_comma?",":"", range->ranges[i].low);
      } else {
       ep_strbuf_append_printf(strbuf, "%s%u-%u", prepend_comma?",":"", range->ranges[i].low, range->ranges[i].high);
      }
      prepend_comma = TRUE;
   }

   return strbuf->str;
}

/* Create a copy of a range. */
range_t *range_copy(range_t *src)
{
   range_t *dst;
   size_t range_size;

   range_size = RANGE_HDR_SIZE + src->nranges*sizeof (range_admin_t);
   dst = g_malloc(range_size);
   memcpy(dst, src, range_size);
   return dst;
}

#if 0
/* This is a debug function to check the range functionality */
static void value_is_in_range_check(range_t *range, guint32 val)
{

  /* Print the result for a given value */
  printf("Function : value_is_in_range_check Number %u\t",val);

  if (value_is_in_range(range, val)) {
     printf("is in range\n");
  } else {
     printf("is not in range\n");
  }
}
#endif


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