From 51596dc4579f2257e744828408f41462432b4aa3 Mon Sep 17 00:00:00 2001
From: Sebastien Lorquet <sebastien@lorquet.fr>
Date: Thu, 25 Aug 2016 08:00:50 -0600
Subject: [PATCH] Updata difftime. Add a version of difftime for the case
where the platform does not support type double
---
include/time.h | 6 +++++-
libc/time/Make.defs | 5 +----
libc/time/lib_difftime.c | 29 +++++++++++++++++++++++++----
3 files changed, 31 insertions(+), 9 deletions(-)
diff --git a/include/time.h b/include/time.h
index 649e4f9f39..f524357013 100644
--- a/include/time.h
+++ b/include/time.h
@@ -41,6 +41,7 @@
********************************************************************************/
#include <nuttx/config.h>
+#include <nuttx/compiler.h>
#include <sys/types.h>
#include <stdint.h>
@@ -103,6 +104,7 @@
/********************************************************************************
* Public Types
********************************************************************************/
+
/* Scalar types */
typedef uint32_t time_t; /* Holds time in seconds */
@@ -214,8 +216,10 @@ FAR char *ctime_r(FAR const time_t *timep, FAR char *buf);
time_t time(FAR time_t *timep);
-#if defined(CONFIG_LIBC_DIFFTIME)
+#ifdef CONFIG_HAVE_DOUBLE
double difftime(time_t time1, time_t time0);
+#else
+float difftime(time_t time1, time_t time0);
#endif
int timer_create(clockid_t clockid, FAR struct sigevent *evp,
diff --git a/libc/time/Make.defs b/libc/time/Make.defs
index 0aeda13eef..68e6243687 100644
--- a/libc/time/Make.defs
+++ b/libc/time/Make.defs
@@ -37,6 +37,7 @@
CSRCS += lib_strftime.c lib_calendar2utc.c lib_daysbeforemonth.c
CSRCS += lib_gettimeofday.c lib_isleapyear.c lib_settimeofday.c lib_time.c
+CSRCS += lib_difftime.c
ifdef CONFIG_LIBC_LOCALTIME
CSRCS += lib_localtime.c lib_asctime.c lib_asctimer.c lib_ctime.c
@@ -49,10 +50,6 @@ CSRCS += lib_ctimer.c
endif
endif
-ifdef CONFIG_LIBC_DIFFTIME
-CSRCS += lib_difftime.c
-endif
-
# Add the time directory to the build
DEPPATH += --dep-path time
diff --git a/libc/time/lib_difftime.c b/libc/time/lib_difftime.c
index 3487d118cd..ee9a62ebb2 100644
--- a/libc/time/lib_difftime.c
+++ b/libc/time/lib_difftime.c
@@ -40,10 +40,9 @@
#include <nuttx/config.h>
#include <nuttx/compiler.h>
+#include <stdint.h>
#include <time.h>
-#ifdef CONFIG_HAVE_DOUBLE
-
/****************************************************************************
* Public Functions
****************************************************************************/
@@ -53,13 +52,35 @@
*
* Description:
* The difftime() function returns the number of seconds elapsed
- * between time time1 and time time0, represented as a double.
+ * 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 >= time2)
+ {
+ /* 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?
+ */
-#endif /* CONFIG_HAVE_DOUBLE */
+ return (float)((int32_t)(time1 - time0))
+ }
+}
+#endif
--
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