📄 net_tmr.c
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used = DEF_BIT_IS_SET(NetTmr_TaskListPtr->Flags, NET_TMR_FLAG_USED);
if (used != DEF_YES) { /* If tmr NOT used, ... */
NetTmr_DiscardTaskTmr(); /* ... discard tmr task tmr (see Note #4b1) ... */
NET_CTR_ERR_INC(NetTmr_ErrNotUsedCtr);
NetOS_Unlock();
return; /* ... & abort tmr task (see Note #4b2). */
}
#endif
ptmr = (NET_TMR *)NetTmr_TaskListPtr;
NetTmr_TaskListPtr = (NET_TMR *)NetTmr_TaskListPtr->NextPtr; /* Set next tmr to update (see Note #5a1). */
if (ptmr->TmrVal > 0) { /* If tmr val > 0, dec tmr val (see Note #6). */
ptmr->TmrVal--;
} else { /* Else tmr expired; ... */
obj = ptmr->Obj; /* Get obj for ... */
fnct = ptmr->Fnct; /* ... tmr expiration fnct. */
NetTmr_Free(ptmr); /* ... free tmr (see Note #7); ... */
if (fnct != (CPU_FNCT_PTR)0) { /* ... & if avail, ... */
fnct(obj); /* ... exec tmr expiration fnct. */
}
}
}
#if (NET_ERR_CFG_ARG_CHK_DBG_EN == DEF_ENABLED) /* Clr tmr task ptr (see Note #5b1). */
NetTmr_TaskListPtr = (NET_TMR *)0;
#endif
NetOS_Unlock(); /* Release net lock. */
}
/*$PAGE*/
/*
*********************************************************************************************************
* NetTmr_Get()
*
* Description : (1) Allocate & initialize a network timer :
*
* (a) Get timer
* (b) Validate timer
* (c) Initialize timer
* (d) Insert timer at head of Timer Task List
* (e) Update timer pool statistics
* (f) Return pointer to timer
* OR
* Null pointer & error code, on failure
*
* (2) The timer pool is implemented as a stack :
*
* (a) 'NetTmr_PoolPtr' points to the head of the timer pool.
*
* (b) Timers' 'NextPtr's link each timer to form the timer pool stack.
*
* (c) Timers are inserted & removed at the head of the timer pool stack.
*
*
* Timers are
* inserted & removed
* at the head
* (see Note #2c)
*
* | NextPtr
* | (see Note #2b)
* v |
* |
* ------- ------- v ------- -------
* Timer Pool ---->| |------>| |------>| |------>| |
* Pointer | | | | | | | |
* | | | | | | | |
* (see Note #2a) ------- ------- ------- -------
*
* | |
* |<------------ Pool of Free Timers ------------>|
* | (see Note #2) |
*
*
* Argument(s) : obj Pointer to object that requests a timer.
*
* fnct Pointer to object function to execute when timer expires (see Note #3).
*
* time Initial timer value (in seconds expressed in 'NET_TMR_TICK' ticks)
* [see also Note #4].
*
* flags Flags to select timer options; bit-field flags logically OR'd :
*
* NET_TMR_FLAG_NONE NO timer flags selected.
*
* perr Pointer to variable that will receive the return error code from this function :
*
* NET_TMR_ERR_NONE Network timer successfully allocated & initialized.
* NET_TMR_ERR_NULL_OBJ Argument 'obj' passed a NULL pointer.
* NET_TMR_ERR_NULL_FNCT Argument 'fnct' passed a NULL pointer.
* NET_TMR_ERR_NONE_AVAIL NO available timers to allocate.
* NET_TMR_ERR_INVALID_TYPE Network timer is NOT a valid timer type.
*
* Return(s) : Pointer to network timer, if NO errors.
*
* Pointer to NULL, otherwise.
*
* Caller(s) : various.
*$PAGE*
* Note(s) : (3) Ideally, network timer expiration functions could be defined as '[(void) (OBJECT *)]'
* type functions -- even though network timer API functions cast expiration functions
* to generic 'CPU_FNCT_PTR' type (i.e. '[(void) (void *)]').
*
* (a) (1) Unfortunately, ISO-IEC 9899-1999 ANSI-C, Section 6.3.2.3.7 states that "a
* pointer to an object ... may be converted to a pointer to a different object
* ... [but] if the resulting pointer is not correctly aligned ... the behavior
* is undefined".
*
* And since compilers may NOT correctly convert 'void' pointers to non-'void'
* pointer arguments, network timer expiration functions MUST avoid incorrect
* pointer conversion behavior between 'void' pointer parameters & non-'void'
* pointer arguments & therefore CANNOT be defined as '[(void) (OBJECT *)]'.
*
* (2) However, Section 6.3.2.3.1 states that "a pointer to void may be converted
* to or from a pointer to any ... object ... A pointer to any ... object ...
* may be converted to a pointer to void and back again; the result shall
* compare equal to the original pointer".
*
* (b) Therefore, to correctly convert 'void' pointer objects back to appropriate
* network object pointer objects, network timer expiration functions MUST :
*
* (1) Be defined as 'CPU_FNCT_PTR' type (i.e. '[(void) (void *)]'); & ...
* (2) Explicitly cast 'void' pointer arguments to specific object pointers.
*
* (4) Timer value of 0 ticks/seconds allowed; next tick will expire timer.
*
* See also 'NetTmr_TaskHandler() Note #6'.
*
* (5) #### 'flags' currently unused (remove before product release if unused).
*********************************************************************************************************
*/
/*$PAGE*/
NET_TMR *NetTmr_Get (void *obj,
CPU_FNCT_PTR fnct,
NET_TMR_TICK time,
CPU_INT16U flags,
NET_ERR *perr)
{
#if ((NET_CTR_CFG_ERR_EN == DEF_ENABLED) && \
(CPU_CFG_CRITICAL_METHOD == CPU_CRITICAL_METHOD_STATUS_LOCAL))
CPU_SR cpu_sr;
#endif
NET_TMR *ptmr;
NET_ERR stat_err;
(void)&flags; /* Prevent compiler warning (see Note #5). */
#if (NET_ERR_CFG_ARG_CHK_DBG_EN == DEF_ENABLED)
/* ------------------- VALIDATE PTRS ------------------ */
if (obj == (void *)0) {
NET_CTR_ERR_INC(NetTmr_ErrNullObjCtr);
*perr = NET_TMR_ERR_NULL_OBJ;
return ((NET_TMR *)0);
}
if (fnct == (CPU_FNCT_PTR)0) {
NET_CTR_ERR_INC(NetTmr_ErrNullFnctCtr);
*perr = NET_TMR_ERR_NULL_FNCT;
return ((NET_TMR *)0);
}
#endif
/* --------------------- GET TMR ---------------------- */
if (NetTmr_PoolPtr != (NET_TMR *)0) { /* If tmr pool NOT empty, get tmr from pool. */
ptmr = (NET_TMR *)NetTmr_PoolPtr;
NetTmr_PoolPtr = (NET_TMR *)ptmr->NextPtr;
} else { /* If none avail, rtn err. */
NET_CTR_ERR_INC(NetTmr_ErrNoneAvailCtr);
*perr = NET_TMR_ERR_NONE_AVAIL;
return ((NET_TMR *)0);
}
#if (NET_ERR_CFG_ARG_CHK_DBG_EN == DEF_ENABLED)
/* ------------------- VALIDATE TMR ------------------- */
if (ptmr->Type != NET_TMR_TYPE_TMR) {
NetTmr_Discard(ptmr);
NET_CTR_ERR_INC(NetTmr_ErrInvalidTypeCtr);
*perr = NET_TMR_ERR_INVALID_TYPE;
return ((NET_TMR *)0);
}
#endif
/* --------------------- INIT TMR --------------------- */
ptmr->PrevPtr = (void *)0;
ptmr->NextPtr = (void *)NetTmr_TaskListHead;
ptmr->Obj = obj;
ptmr->Fnct = fnct;
ptmr->TmrVal = time; /* Set tmr val (in ticks/seconds). */
ptmr->Flags = NET_TMR_FLAG_NONE;
DEF_BIT_SET(ptmr->Flags, NET_TMR_FLAG_USED); /* Set tmr as used. */
/* ---------- INSERT TMR INTO TMR TASK LIST ----------- */
if (NetTmr_TaskListHead != (NET_TMR *)0) { /* If list NOT empty, insert before head. */
NetTmr_TaskListHead->PrevPtr = (void *)ptmr;
}
NetTmr_TaskListHead = ptmr; /* Insert tmr @ list head. */
/* --------------- UPDATE TMR POOL STATS -------------- */
NetStat_PoolEntryUsedInc(&NetTmr_PoolStat, &stat_err);
*perr = NET_TMR_ERR_NONE;
return (ptmr); /* --------------------- RTN TMR ---------------------- */
}
/*$PAGE*/
/*
*********************************************************************************************************
* NetTmr_Free()
*
* Description : (1) Free a network timer :
*
* (a) Remove timer from Timer Task List
* (b) Clear timer controls
* (c) Free timer back to timer pool
* (d) Update timer pool statistics
*
*
* Argument(s) : ptmr Pointer to a network timer.
*
* Return(s) : none.
*
* Caller(s) : various.
*
* Note(s) : (2) #### To prevent freeing a timer already freed via previous timer free, NetTmr_Free()
* checks the timer's 'USED' flag BEFORE freeing the timer.
*
* This prevention is only best-effort since any invalid duplicate timer frees MAY be
* asynchronous to potentially valid timer gets. Thus the invalid timer free(s) MAY
* corrupt the timer's valid operation(s).
*
* However, since the primary tasks of the network protocol suite are prevented from
* running concurrently (see 'net.h Note #2'), it is NOT necessary to protect network
* timer resources from possible corruption since no asynchronous access from other
* network tasks is possible.
*
* (3) Since NetTmr_TaskHandler() is asynchronous to NetTmr_Free() [via execution of certain
* timer expiration functions], the Timer Task List timer ('NetTmr_TaskListPtr') MUST be
* coordinated with NetTmr_Free() to avoid Timer Task List corruption :
*
* (a) Whenever the Timer Task List timer is freed, the Timer Task List timer MUST be
* advanced to the next valid & available timer in the Timer Task List.
*
* See also 'NetTmr_TaskHandler() Note #5a2'.
*********************************************************************************************************
*/
/*$PAGE*/
void NetTmr_Free (NET_TMR *ptmr)
{
#if ((NET_ERR_CFG_ARG_CHK_DBG_EN == DEF_ENABLED) && \
(NET_CTR_CFG_ERR_EN == DEF_ENABLED) && \
(CPU_CFG_CRITICAL_METHOD == CPU_CRITICAL_METHOD_STATUS_LOCAL))
CPU_SR cpu_sr;
#endif
#if (NET_ERR_CFG_ARG_CHK_DBG_EN == DEF_ENABLED)
CPU_BOOLEAN used;
#endif
NET_TMR *pprev;
NET_TMR *pnext;
NET_ERR stat_err;
/* ------------------- VALIDATE PTR ------------------- */
if (ptmr == (NET_TMR *)0) {
return;
}
#if (NET_ERR_CFG_ARG_CHK_DBG_EN == DEF_ENABLED)
/* ------------------- VALIDATE TYPE ------------------ */
if (ptmr->Type != NET_TMR_TYPE_TMR) {
NetTmr_Discard(ptmr);
NET_CTR_ERR_INC(NetTmr_ErrInvalidTypeCtr);
return;
}
/* ----------------- VALIDATE TMR USED ---------------- */
used = DEF_BIT_IS_SET(ptmr->Flags, NET_TMR_FLAG_USED);
if (used != DEF_YES) { /* If tmr NOT used, ... */
NET_CTR_ERR_INC(NetTmr_ErrNotUsedCtr);
return; /* ... rtn but do NOT free (see Note #2). */
}
#endif
/* ----------- REMOVE TMR FROM TMR TASK LIST ---------- */
if (ptmr == NetTmr_TaskListPtr) { /* If tmr is next Tmr Task tmr to update, ... */
pnext = (NET_TMR *)NetTmr_TaskListPtr->NextPtr;
NetTmr_TaskListPtr = (NET_TMR *)pnext; /* ... adv Tmr Task ptr to skip this tmr (see Note #3a).*/
}
pprev = (NET_TMR *)ptmr->PrevPtr;
pnext = (NET_TMR *)ptmr->NextPtr;
if (pprev != (NET_TMR *)0) { /* If ptmr is NOT the head of Tmr Task List, ... */
pprev->NextPtr = (void *)pnext; /* ... set pprev's NextPtr to skip ptmr. */
} else { /* Else set pnext as head of Tmr Task List. */
NetTmr_TaskListHead = (NET_TMR *)pnext;
}
if (pnext != (NET_TMR *)0) { /* If ptmr is NOT @ the tail of Tmr Task List, ... */
pnext->PrevPtr = (void *)pprev; /* ... set pnext's PrevPtr to skip ptmr. */
}
/* ---------------------- CLR TMR --------------------- */
DEF_BIT_CLR(ptmr->Flags, NET_TMR_FLAG_USED); /* Set tmr as NOT used. */
#if (NET_DBG_CFG_MEM_CLR_EN == DEF_ENABLED)
NetTmr_Clr(ptmr);
#endif
/* --------------------- FREE TMR --------------------- */
ptmr->NextPtr = (void *)NetTmr_PoolPtr;
NetTmr_PoolPtr = (NET_TMR *)ptmr;
/* -------------- UPDATE TMR POOL STATS --------------- */
NetStat_PoolEntryUsedDec(&NetTmr_PoolStat, &stat_err);
}
/*$PAGE*/
/*
*********************************************************************************************************
* NetTmr_Set()
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