qvalue.c

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/*
 * $Id: qvalue.c 4518 2008-07-28 15:39:28Z henningw $
 *
 * Handling of the q value
 *
 * Copyright (C) 2004 FhG FOKUS
 *
 * This file is part of Kamailio, a free SIP server.
 *
 * Kamailio 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
 *
 * Kamailio 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
 */

/*!
 * \file
 * \brief Functions related to the SIP q value
 */


#include "error.h"
#include "qvalue.h"


/*
 * Convert string representation of q parameter in qvalue_t
 */
int str2q(qvalue_t* q, char* s, int len)
{
   int i, digits, order;

        /* States and equivalent regular expressions of input */
   enum {
      ST_START,   /* (SPC|TAB)* */
      ST_0,       /* 0+ */
      ST_1,       /* 1 */
      ST_0_PT,    /* 0*\. */
      ST_1_PT,    /* 1\. */
      ST_1_PT_0,  /* 1\.0+ */
      ST_0_PT_N   /* 0*\.[0-9]+ */
   } state = ST_START;

   if (!q || !s) {
      return E_INVALID_PARAMS;
   }

   digits = 1;
   order = 100;
   for(i = 0; i < len; i++) {
      switch(state) {
      case ST_START:
         switch(s[i]) {
         case ' ':
         case '\t':
            break;

         case '0':
            *q = 0;
            state = ST_0;
            break;

         case '1':
            *q = 1000;
            state = ST_1;
            break;

         case '.':
            state = ST_0_PT;
            break;

         default:
            return E_Q_INV_CHAR;
         }
         break;

      case ST_0:
         switch(s[i]) {
         case '0':
            break;

         case '.':
            state = ST_0_PT;
            break;

         case '1':
            *q = 1000;
            state = ST_1;
            break;

         default:
            if (s[i] >= '2' && s[i] <= '9') {
               return E_Q_TOO_BIG;
            } else {
               return E_Q_INV_CHAR;
            }
         }
         break;

      case ST_1:
         if (s[i] == '.') {
            state = ST_1_PT;
            break;
         } else {
            if (s[i] >= '0' && s[i] <= '9') {
               return E_Q_TOO_BIG;
            } else {
               return E_Q_INV_CHAR;
            }
         }
         break;

      case ST_0_PT:
         if (s[i] >= '0' && s[i] <= '9') {
            *q =  (s[i] - '0') * order;
            order /= 10;
            state = ST_0_PT_N;
         } else {
            return E_Q_INV_CHAR;
         }
         break;

      case ST_1_PT:
         if (s[i] == '0') {
            state = ST_1_PT_0;
         } else {
            if (s[i] >= '1' && s[i] <= '9') {
               return E_Q_TOO_BIG;
            } else {
               return E_Q_INV_CHAR;
            }
         }
         break;

      case ST_1_PT_0:
         if (s[i] == '0') {
            break;
         } else {
            if (s[i] >= '1' && s[i] <= '9') {
               return E_Q_TOO_BIG;
            } else {
               return E_Q_INV_CHAR;
            }
         }
         break;

      case ST_0_PT_N:
         if (s[i] >= '0' && s[i] <= '9') {
            if (digits <= 3) {
               *q += (s[i] - '0') * order;
               order /= 10;
               digits++;
            }
         } else {
            return E_Q_INV_CHAR;
         }
         break;
      }
   }

   switch(state) {
   case ST_START:
      return E_Q_EMPTY;
      
   case ST_0_PT:
   case ST_1_PT:
      return E_Q_DEC_MISSING;
      
   default:
      return 0;
   }
}

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