nuttx/libs/libc/time/lib_difftime.c
Gregory Nutt cf99fb40c9 This commit moves all of the libraries under a common directory called libs/. This most certainly break libcxx and uClibc++ for now.
Squashed commit of the following:

    libs/libxx:  Fix some confusing in naming.  If the directory is called libxx, then the library must be libxx.a (unless perhaps LIBCXX is selected).
    libs/:  Fix paths in moved library directories.
    libs:  Brute force move of libc, libnx, and libxx to libs.  Cannot yet build it in that configuration.
2018-05-29 13:21:26 -06:00

87 lines
3.2 KiB
C

/****************************************************************************
* libs/libc/time/lib_difftime.c
*
* Copyright (C) 2016-2017 Gregory Nutt. All rights reserved.
* Author: Sebastien Lorquet <sebastien@lorquet.fr>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <nuttx/compiler.h>
#include <stdint.h>
#include <time.h>
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: difftime
*
* Description:
* The difftime() function returns the number of seconds elapsed
* between time time1 and time time0, represented as a double or a float.
* Float is used if the platform does not support double. However, when
* using a float, some precision may be lost for big differences.
*
****************************************************************************/
#ifdef CONFIG_HAVE_DOUBLE
double difftime(time_t time1, time_t time0)
{
return (double)time1 - (double)time0;
}
#else
float difftime(time_t time1, time_t time0)
{
if (time1 >= time0)
{
/* Result will be positive (even though bit 31 may be set on very large
* differences!)
*/
return (float)((uint32_t)(time1 - time0));
}
else
{
/* Result will be negative. REVISIT: Am I missing any case where bit 31
* might not be set?
*/
return (float)((int32_t)(time1 - time0));
}
}
#endif