1 files changed, 129 insertions, 0 deletions
diff --git a/nuttx/sched/clock_abstime2ticks.c b/nuttx/sched/clock_abstime2ticks.c
new file mode 100644
index 000000000..359bd2165
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+++ b/nuttx/sched/clock_abstime2ticks.c
@@ -0,0 +1,129 @@
+/********************************************************************************
+ * clock_abstime2ticks.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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 <sys/types.h>
+#include <time.h>
+#include <errno.h>
+#include <debug.h>
+#include "clock_internal.h"
+
+/********************************************************************************
+ * Definitions
+ ********************************************************************************/
+
+/********************************************************************************
+ * Private Type Declarations
+ ********************************************************************************/
+
+/********************************************************************************
+ * Global Variables
+ ********************************************************************************/
+
+/********************************************************************************
+ * Private Variables
+ ********************************************************************************/
+
+/********************************************************************************
+ * Private Functions
+ ********************************************************************************/
+
+/********************************************************************************
+ * Public Functions
+ ********************************************************************************/
+
+/********************************************************************************
+ * Function:  clock_abstime2ticks
+ *
+ * Description:
+ *   Convert an absolute timespec delay to system timer ticks.
+ *
+ * Parameters:
+ *   clockid - The timing source to use in the conversion
+ *   reltime - Convert this absolue time to system clock ticks.
+ *   ticks - Return the converted number of ticks here.
+ *
+ * Return Value:
+ *   OK on success; A non-zero error number on failure;
+ *
+ * Assumptions:
+ *   Interrupts should be disabled so that the time is not changing during the
+ *   calculation
+ *
+ ********************************************************************************/
+
+extern int clock_abstime2ticks(clockid_t clockid, const struct timespec *abstime,
+                               int *ticks)
+{
+  struct timespec currtime;
+  struct timespec reltime;
+  sint32          relusec;
+  int             ret;
+
+  /* Convert the timespec to clock ticks.  NOTE: Here we use
+   * internal knowledge that CLOCK_REALTIME is defined to be zero!
+   */
+
+  ret = clock_gettime(clockid, &currtime);
+  if (ret)
+    {
+      return EINVAL;
+    }
+
+  /* The relative time to wait is the absolute time minus the
+   * current time.
+   */
+
+  reltime.tv_nsec = (abstime->tv_nsec - currtime.tv_nsec);
+  reltime.tv_sec  = (abstime->tv_sec  - currtime.tv_sec);
+
+  /* Check if we were supposed to borrow from the seconds to
+   * borrow from the seconds
+   */
+
+  if (reltime.tv_nsec < 0)
+    {
+      reltime.tv_nsec += NSEC_PER_SEC;
+      reltime.tv_sec  -= 1;
+    }
+
+  /* Convert this relative time into microseconds.*/
+
+  return clock_time2ticks(&reltime, ticks);
+}