text: /* util.c
  ** strophe XMPP client library -- various utility functions
  **
  ** Copyright (C) 2005-2009 Collecta, Inc. 
  **
  **  This software is provided AS-IS with no warranty, either express
  **  or implied.
  **
  **  This program is dual licensed under the MIT and GPLv3 licenses.
  */
  
  /** @file
   *  Utility functions.
   */
  
  #include <stdio.h>
  #include <string.h>
  
  #ifdef _WIN32
  #include <winsock2.h>
  #else
  #include <sys/time.h>
  #include <time.h>
  #endif
  
  #include "strophe.h"
  #include "common.h"
  #include "ostypes.h"
  #include "util.h"
  
  /** implement our own strdup that uses the ctx allocator */
  /** Duplicate a string.
   *  This function replaces the standard strdup library call with a version
   *  that uses the Strophe context object's allocator.
   *
   *  @param ctx a Strophe context object
   *  @param s a string
   *
   *  @return a new allocates string with the same data as s or NULL on error
   */
  char *xmpp_strdup(const xmpp_ctx_t * const ctx, const char * const s)
  {
      size_t len;
      char *copy;
  
      len = strlen(s);
      copy = xmpp_alloc(ctx, len + 1);
      if (!copy) {
          xmpp_error(ctx, "xmpp", "failed to allocate required memory");
          return NULL;
      }
  
      memcpy(copy, s, len + 1);
  
      return copy;
  }
  
  /** Return an integer based time stamp.
   *  This function uses gettimeofday or timeGetTime (on Win32 platforms) to
   *  compute an integer based time stamp.  This is used internally by the
   *  event loop and timed handlers.
   *
   *  @return an integer time stamp
   */
  uint64_t time_stamp(void)
  {
  #ifdef _WIN32
      return timeGetTime();
  #else
      struct timeval tv;
  
      gettimeofday(&tv, NULL);
  
      return (uint64_t)tv.tv_sec * 1000 + (uint64_t)tv.tv_usec / 1000;
  #endif
  }
  
  /** Get the time elapsed between two time stamps.
   *  This function returns the time elapsed between t1 and t2 by subtracting
   *  t1 from t2.  If t2 happened before t1, the result will be negative.  This
   *  function is used internally by the event loop and timed handlers.
   *
   *  @param t1 first time stamp
   *  @param t2 second time stamp
   *
   *  @return number of milliseconds between the stamps
   */
  uint64_t time_elapsed(uint64_t t1, uint64_t t2)
  {
      return (uint64_t)(t2 - t1);
  }
  
  /** Disconnect the stream with a memory error.
   *  This is a convenience function used internally by various parts of
   *  the Strophe library for terminating the connection because of a 
   *  memory error.
   *
   *  @param conn a Strophe connection object
   */
  void disconnect_mem_error(xmpp_conn_t * const conn)
  {
      xmpp_error(conn->ctx, "xmpp", "Memory allocation error");
      xmpp_disconnect(conn);
  }
  