utils.h

Go to the documentation of this file.

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 * \brief Utility functions
 */

#ifndef _ASTERISK_UTILS_H
#define _ASTERISK_UTILS_H

#include "asterisk/compat.h"

#include <netinet/in.h>
#include <arpa/inet.h>  /* we want to override inet_ntoa */
#include <netdb.h>
#include <limits.h>

#include "asterisk/lock.h"
#include "asterisk/time.h"
#include "asterisk/strings.h"

/*! \note
 \verbatim
   Note:
   It is very important to use only unsigned variables to hold
   bit flags, as otherwise you can fall prey to the compiler's
   sign-extension antics if you try to use the top two bits in
   your variable.

   The flag macros below use a set of compiler tricks to verify
   that the caller is using an "unsigned int" variable to hold
   the flags, and nothing else. If the caller uses any other
   type of variable, a warning message similar to this:

   warning: comparison of distinct pointer types lacks cast
   will be generated.

   The "dummy" variable below is used to make these comparisons.

   Also note that at -O2 or above, this type-safety checking
   does _not_ produce any additional object code at all.
 \endverbatim
*/

extern unsigned int __unsigned_int_flags_dummy;

#define ast_test_flag(p,flag)       ({ \
               typeof ((p)->flags) __p = (p)->flags; \
               typeof (__unsigned_int_flags_dummy) __x = 0; \
               (void) (&__p == &__x); \
               ((p)->flags & (flag)); \
               })

#define ast_set_flag(p,flag)     do { \
               typeof ((p)->flags) __p = (p)->flags; \
               typeof (__unsigned_int_flags_dummy) __x = 0; \
               (void) (&__p == &__x); \
               ((p)->flags |= (flag)); \
               } while(0)

#define ast_clear_flag(p,flag)      do { \
               typeof ((p)->flags) __p = (p)->flags; \
               typeof (__unsigned_int_flags_dummy) __x = 0; \
               (void) (&__p == &__x); \
               ((p)->flags &= ~(flag)); \
               } while(0)

#define ast_copy_flags(dest,src,flagz) do { \
               typeof ((dest)->flags) __d = (dest)->flags; \
               typeof ((src)->flags) __s = (src)->flags; \
               typeof (__unsigned_int_flags_dummy) __x = 0; \
               (void) (&__d == &__x); \
               (void) (&__s == &__x); \
               (dest)->flags &= ~(flagz); \
               (dest)->flags |= ((src)->flags & (flagz)); \
               } while (0)

#define ast_set2_flag(p,value,flag) do { \
               typeof ((p)->flags) __p = (p)->flags; \
               typeof (__unsigned_int_flags_dummy) __x = 0; \
               (void) (&__p == &__x); \
               if (value) \
                  (p)->flags |= (flag); \
               else \
                  (p)->flags &= ~(flag); \
               } while (0)

/* Non-type checking variations for non-unsigned int flags.  You
   should only use non-unsigned int flags where required by 
   protocol etc and if you know what you're doing :)  */
#define ast_test_flag_nonstd(p,flag)      ({ \
               ((p)->flags & (flag)); \
               })

#define ast_set_flag_nonstd(p,flag)       do { \
               ((p)->flags |= (flag)); \
               } while(0)

#define ast_clear_flag_nonstd(p,flag)     do { \
               ((p)->flags &= ~(flag)); \
               } while(0)

#define ast_copy_flags_nonstd(dest,src,flagz)   do { \
               (dest)->flags &= ~(flagz); \
               (dest)->flags |= ((src)->flags & (flagz)); \
               } while (0)

#define ast_set2_flag_nonstd(p,value,flag)   do { \
               if (value) \
                  (p)->flags |= (flag); \
               else \
                  (p)->flags &= ~(flag); \
               } while (0)

#define AST_FLAGS_ALL UINT_MAX

struct ast_flags {
   unsigned int flags;
};

struct ast_hostent {
   struct hostent hp;
   char buf[1024];
};

struct hostent *ast_gethostbyname(const char *host, struct ast_hostent *hp);

/* ast_md5_hash 
   \brief Produces MD5 hash based on input string */
void ast_md5_hash(char *output, char *input);

/* ast_sha1_hash
   \brief Produces SHA1 hash based on input string */
void ast_sha1_hash(char *output, char *input);

int ast_base64encode(char *dst, const unsigned char *src, int srclen, int max);
int ast_base64decode(unsigned char *dst, const char *src, int max);

/*! ast_uri_encode
   \brief Turn text string to URI-encoded %XX version 
   At this point, we're converting from ISO-8859-x (8-bit), not UTF8
   as in the SIP protocol spec 
   If doreserved == 1 we will convert reserved characters also.
   RFC 2396, section 2.4
   outbuf needs to have more memory allocated than the instring
   to have room for the expansion. Every char that is converted
   is replaced by three ASCII characters.
   \param string  String to be converted
   \param outbuf  Resulting encoded string
   \param buflen  Size of output buffer
   \param doreserved Convert reserved characters
*/

char *ast_uri_encode(char *string, char *outbuf, int buflen, int doreserved);

/*!   \brief Decode URI, URN, URL (overwrite string)
   \param s String to be decoded 
 */
void ast_uri_decode(char *s);

static force_inline void ast_slinear_saturated_add(short *input, short *value)
{
   int res;

   res = (int) *input + *value;
   if (res > 32767)
      *input = 32767;
   else if (res < -32767)
      *input = -32767;
   else
      *input = (short) res;
}
   
static force_inline void ast_slinear_saturated_multiply(short *input, short *value)
{
   int res;

   res = (int) *input * *value;
   if (res > 32767)
      *input = 32767;
   else if (res < -32767)
      *input = -32767;
   else
      *input = (short) res;
}

static force_inline void ast_slinear_saturated_divide(short *input, short *value)
{
   *input /= *value;
}

int test_for_thread_safety(void);

const char *ast_inet_ntoa(char *buf, int bufsiz, struct in_addr ia);

#ifdef inet_ntoa
#undef inet_ntoa
#endif
#define inet_ntoa __dont__use__inet_ntoa__use__ast_inet_ntoa__instead__

int ast_utils_init(void);
int ast_wait_for_input(int fd, int ms);

/*! Compares the source address and port of two sockaddr_in */
static force_inline int inaddrcmp(const struct sockaddr_in *sin1, const struct sockaddr_in *sin2)
{
   return ((sin1->sin_addr.s_addr != sin2->sin_addr.s_addr) 
      || (sin1->sin_port != sin2->sin_port));
}

#define AST_STACKSIZE 256 * 1024
#define ast_pthread_create(a,b,c,d) ast_pthread_create_stack(a,b,c,d,0)
int ast_pthread_create_stack(pthread_t *thread, pthread_attr_t *attr, void *(*start_routine)(void *), void *data, size_t stacksize);

/*!
   \brief Process a string to find and replace characters
   \param start The string to analyze
   \param find The character to find
   \param replace_with The character that will replace the one we are looking for
*/
char *ast_process_quotes_and_slashes(char *start, char find, char replace_with);

#ifndef HAVE_GETLOADAVG
int getloadavg(double *list, int nelem);
#endif

/*!
  \brief Disable PMTU discovery on a socket
  \param sock The socket to manipulate
  \return Nothing

  On Linux, UDP sockets default to sending packets with the Dont Fragment (DF)
  bit set. This is supposedly done to allow the application to do PMTU
  discovery, but Asterisk does not do this.

  Because of this, UDP packets sent by Asterisk that are larger than the MTU
  of any hop in the path will be lost. This function can be called on a socket
  to ensure that the DF bit will not be set.
 */
void ast_enable_packet_fragmentation(int sock);

#endif /* _ASTERISK_UTILS_H */