Fix #429, update OSAL code to use time accessors

Do not access members of OS_time_t directly, instead
use conversion/accessor inline functions to get the
desired value.

Update the "stat" structure output by OS_stat to use
the OS_time_t struct instead of int32, and update
the OS_stat implemention to transfer the full resolution
if it supports it (POSIX.1-2008 or newer).

src/os/inc/osapi-clock.h

@@ -28,14 +28,26 @@
 #include "osconfig.h"
 #include "common_types.h"
 
-/** @brief OSAL time */
+/**
+ * @brief OSAL time interval structure
+ *
+ * This is used to represent a basic time interval.
+ *
+ * When used with OS_GetLocalTime/OS_SetLocalTime, this represents the
+ * interval from the OS's epoch point, typically 01 Jan 1970 00:00:00 UTC
+ * on systems that have a persistent real time clock (RTC), or the system
+ * boot time if there is no RTC available.
+ *
+ * Applications should not directly access fields within this structure,
+ * as the definition may change in future versions of OSAL.  Instead,
+ * applications should use the accessor/conversion methods defined below.
+ */
 typedef struct
 {
     uint32 seconds;
     uint32 microsecs;
 } OS_time_t;
 
-
 /** @defgroup OSAPIClock OSAL Real Time Clock APIs
  * @{
  */
@@ -66,7 +78,280 @@ int32 OS_GetLocalTime(OS_time_t *time_struct);
  *
  * @return Set local time status, see @ref OSReturnCodes
  */
-int32 OS_SetLocalTime(OS_time_t *time_struct);
+int32 OS_SetLocalTime(const OS_time_t *time_struct);
+
+
+/*-------------------------------------------------------------------------------------*/
+/*
+ * Accessor / Unit Conversion routines for OS_time_t
+ *
+ * These routines allow the user to simply interpret OS_time_t intervals into
+ * in normalized units of whole seconds, milliseconds, microseconds, or nanoseconds.
+ */
+/*-------------------------------------------------------------------------------------*/
+
+/*-------------------------------------------------------------------------------------*/
+/**
+ * @brief Get interval from an OS_time_t object normalized to whole number of seconds
+ *
+ * Extracts the number of whole seconds from a given OS_time_t object, discarding
+ * any fractional component.
+ *
+ * This may also replace a direct read of the "seconds" field from
+ * the OS_time_t object from previous versions of OSAL, where the
+ * structure was defined with separate seconds/microseconds fields.
+ *
+ * @sa OS_TimeGetMicrosecondsPart()
+ *
+ * @param[in] tm    Time interval value
+ * @returns   Whole number of seconds in time interval
+ */
+static inline int64 OS_TimeGetTotalSeconds(OS_time_t tm)
+{
+    return (tm.seconds);
+}
+
+/*-------------------------------------------------------------------------------------*/
+/**
+ * @brief Get interval from an OS_time_t object normalized to millisecond units
+ *
+ * Note this refers to the complete interval, not just the fractional part.
+ *
+ * @param[in] tm    Time interval value
+ * @returns   Whole number of milliseconds in time interval
+ */
+static inline int64 OS_TimeGetTotalMilliseconds(OS_time_t tm)
+{
+    return (((int64)tm.seconds * 1000) + (tm.microsecs / 1000));
+}
+
+/*-------------------------------------------------------------------------------------*/
+/**
+ * @brief Get interval from an OS_time_t object normalized to microsecond units
+ *
+ * Note this refers to the complete interval, not just the fractional part.
+ *
+ * @param[in] tm    Time interval value
+ * @returns   Whole number of microseconds in time interval
+ */
+static inline int64 OS_TimeGetTotalMicroseconds(OS_time_t tm)
+{
+    return (((int64)tm.seconds * 1000000) + tm.microsecs);
+}
+
+/*-------------------------------------------------------------------------------------*/
+/**
+ * @brief Get interval from an OS_time_t object normalized to nanosecond units
+ *
+ * Note this refers to the complete interval, not just the fractional part.
+ *
+ * @note There is no protection against overflow of the 64-bit return value.
+ * Applications must use caution to ensure that the interval does not exceed the
+ * representable range of a signed 64 bit integer - approximately 140 years.
+ *
+ * @param[in] tm    Time interval value
+ * @returns   Whole number of microseconds in time interval
+ */
+static inline int64 OS_TimeGetTotalNanoseconds(OS_time_t tm)
+{
+    return (((int64)tm.seconds * 1000000000) + (tm.microsecs * 1000));
+}
+
+/*-------------------------------------------------------------------------------------*/
+/**
+ * @brief Get subseconds portion (fractional part only) from an OS_time_t object
+ *
+ * Extracts the fractional part from a given OS_time_t object.
+ * Units returned are in ticks, not normalized to any standard time unit.
+ *
+ * @param[in] tm    Time interval value
+ * @returns Fractional/subsecond portion of time interval in ticks
+ */
+static inline int64 OS_TimeGetFractionalPart(OS_time_t tm)
+{
+    return (tm.microsecs);
+}
+
+/*-------------------------------------------------------------------------------------*/
+/**
+ * @brief Get 32-bit normalized subseconds (fractional part only) from an OS_time_t object
+ *
+ * Extracts the fractional part from a given OS_time_t object in maximum precision,
+ * with units of 2^(-32) sec.  This is a base-2 fixed-point fractional value
+ * with the point left-justified in the 32-bit value (i.e. left of MSB).
+ *
+ * This is (mostly) compatible with the CFE "subseconds"  value, where 0x80000000 represents
+ * exactly one half second, and 0 represents a full second.
+ *
+ * @param[in] tm    Time interval value
+ * @returns Fractional/subsecond portion of time interval as 32-bit fixed point value
+ */
+static inline uint32 OS_TimeGetSubsecondsPart(OS_time_t tm)
+{
+    /*
+     * This computation avoids a 32-bit left shift which may not be implemented.
+     *
+     * It also must round up, otherwise this may result in a value one
+     * less than the original when converted back to usec again.
+     */
+    return (((OS_TimeGetFractionalPart(tm) << 26) + 15624) / 15625);
+}
+
+
+/*-------------------------------------------------------------------------------------*/
+/**
+ * @brief Get milliseconds portion (fractional part only) from an OS_time_t object
+ *
+ * Extracts the fractional part from a given OS_time_t object normalized
+ * to units of milliseconds.
+ *
+ * @sa OS_TimeGetTotalSeconds()
+ *
+ * @param[in] tm    Time interval value
+ * @returns Number of milliseconds in time interval
+ */
+static inline uint32 OS_TimeGetMillisecondsPart(OS_time_t tm)
+{
+    return OS_TimeGetFractionalPart(tm) / 1000;
+}
+
+/*-------------------------------------------------------------------------------------*/
+/**
+ * @brief Get microseconds portion (fractional part only) from an OS_time_t object
+ *
+ * Extracts the fractional part from a given OS_time_t object normalized
+ * to units of microseconds.
+ *
+ * This function may be used to adapt applications initially implemented
+ * using an older OSAL version where OS_time_t was a structure containing
+ * a "seconds" and "microsecs" field.
+ *
+ * This function will obtain a value that is compatible with the "microsecs" field of
+ * OS_time_t as it was defined in previous versions of OSAL, as well as the "tv_usec"
+ * field of POSIX-style "struct timeval" values.
+ *
+ * @sa OS_TimeGetTotalSeconds()
+ *
+ * @param[in] tm    Time interval value
+ * @returns Number of microseconds in time interval
+ */
+static inline uint32 OS_TimeGetMicrosecondsPart(OS_time_t tm)
+{
+    return OS_TimeGetFractionalPart(tm);
+}
+
+/*-------------------------------------------------------------------------------------*/
+/**
+ * @brief Get nanoseconds portion (fractional part only) from an OS_time_t object
+ *
+ * Extracts the only number of nanoseconds from a given OS_time_t object.
+ *
+ * This function will obtain a value that is compatible with the "tv_nsec" field
+ * of POSIX-style "struct timespec" values.
+ *
+ * @sa OS_TimeGetTotalSeconds()
+ *
+ * @param[in] tm    Time interval value
+ * @returns Number of nanoseconds in time interval
+ */
+static inline uint32 OS_TimeGetNanosecondsPart(OS_time_t tm)
+{
+    return OS_TimeGetFractionalPart(tm) * 1000;
+}
+
+/*-------------------------------------------------------------------------------------*/
+/**
+ * @brief Assemble/Convert a number of seconds + nanoseconds into an OS_time_t interval
+ *
+ * This creates an OS_time_t value using a whole number of seconds and a fractional
+ * part in units of nanoseconds.  This is the inverse of OS_TimeGetTotalSeconds()
+ * and OS_TimeGetNanosecondsPart(), and should recreate the original OS_time_t
+ * value from these separate values (aside from any potential conversion losses
+ * due to limited resolution of the data types/units).
+ *
+ * @sa OS_TimeGetTotalSeconds(), OS_TimeGetNanosecondsPart()
+ *
+ * @param[in] seconds       Whole number of seconds
+ * @param[in] nanoseconds   Number of nanoseconds (fractional part only)
+ * @returns The input arguments represented as an OS_time_t interval
+ */
+static inline OS_time_t OS_TimeAssembleFromNanoseconds(int64 seconds, uint32 nanoseconds)
+{
+    OS_time_t result;
+    result.seconds   = seconds;
+    result.microsecs = nanoseconds / 1000;
+    return result;
+}
+
+/*-------------------------------------------------------------------------------------*/
+/**
+ * @brief Assemble/Convert a number of seconds + subseconds into an OS_time_t interval
+ *
+ * This creates an OS_time_t value using a whole number of seconds and a fractional
+ * part in units of sub-seconds (1/2^32).  This is the inverse of OS_TimeGetTotalSeconds()
+ * and OS_TimeGetSubsecondsPart(), and should recreate the original OS_time_t
+ * value from these separate values (aside from any potential conversion losses
+ * due to limited resolution of the data types/units).
+ *
+ * @sa OS_TimeGetTotalSeconds(), OS_TimeGetNanosecondsPart()
+ * @param[in] seconds       Whole number of seconds
+ * @param[in] subseconds    Number of subseconds (32 bit fixed point fractional part)
+ * @returns The input arguments represented as an OS_time_t interval
+ */
+static inline OS_time_t OS_TimeAssembleFromSubseconds(int64 seconds, uint32 subseconds)
+{
+    OS_time_t result;
+    result.seconds = seconds;
+    /* this should not round in any way, as the 32-bit input value has higher precision */
+    result.microsecs = ((int64)subseconds * 15625) >> 26;
+    return result;
+}
+
+/*-------------------------------------------------------------------------------------*/
+/**
+ * @brief Computes the sum of two time intervals
+ *
+ * @param[in]  time1 The first interval
+ * @param[in]  time2 The second interval
+ *
+ * @return The sum of the two intervals (time1 + time2)
+ */
+static inline OS_time_t OS_TimeAdd(OS_time_t time1, OS_time_t time2)
+{
+    OS_time_t result = time1;
+    result.seconds += time2.seconds;
+    result.microsecs += time2.microsecs;
+    if (result.microsecs >= 1000000)
+    {
+        ++result.seconds;
+        result.microsecs -= 1000000;
+    }
+    return result;
+}
+
+/*-------------------------------------------------------------------------------------*/
+/**
+ * @brief Computes the difference between two time intervals
+ *
+ * @param[in]  time1 The first interval
+ * @param[in]  time2 The second interval
+ *
+ * @return The difference of the two intervals (time1 - time2)
+ */
+static inline OS_time_t OS_TimeSubtract(OS_time_t time1, OS_time_t time2)
+{
+    OS_time_t result = time1;
+    result.seconds -= time2.seconds;
+    result.microsecs -= time2.microsecs;
+    if (result.microsecs >= 1000000)
+    {
+        --result.seconds;
+        result.microsecs += 1000000;
+    }
+    return result;
+}
+
+
 /**@}*/
 
 #endif

src/os/inc/osapi-file.h

@@ -27,6 +27,7 @@
 
 #include "osconfig.h"
 #include "common_types.h"
+#include "osapi-clock.h"
 
 
 /** @defgroup OSFileAccess OSAL File Access Option Defines
@@ -63,9 +64,9 @@ typedef struct
  */
 typedef struct
 {
-    uint32 FileModeBits;
-    int32  FileTime;
-    size_t FileSize;
+    uint32    FileModeBits;
+    OS_time_t FileTime;
+    size_t    FileSize;
 } os_fstat_t;
 
 /**
@@ -96,8 +97,8 @@ enum
 #define OS_FILESTAT_READ(x) ((x).FileModeBits & OS_FILESTAT_MODE_READ)
 /** @brief Access file stat size field */
 #define OS_FILESTAT_SIZE(x) ((x).FileSize)
-/** @brief Access file stat time field */
-#define OS_FILESTAT_TIME(x) ((x).FileTime)
+/** @brief Access file stat time field as a whole number of seconds */
+#define OS_FILESTAT_TIME(x) (OS_TimeGetTotalSeconds((x).FileTime))
 
 /**
  * @brief Flags that can be used with opening of a file (bitmask)