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Added DBF_OUTLINK support to lnkCalc

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New out key specifying a child link to put the calculated result to.
This commit is contained in:
Andrew Johnson
2018-03-09 22:42:59 -06:00
parent 8f64af96fd
commit 97ea68d40c
2 changed files with 180 additions and 23 deletions
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35
src/std/link/links.dbd.pod
View File

@@ -80,10 +80,30 @@ variable(lnkCalc_debug, int)
=head3 Calculation Link C<"calc">
Calculation links are input links that can evaluate mathematical expressions on
scalar (double- precision floating-point) values obtained from child links, and
return a double-precision floating-point result. The expressions are evaluated
by the EPICS Calc engine, and up to 12 inputs can be provided.
A calculation link is an input link that can evaluate mathematical expressions
on scalar (double-precision floating-point) values obtained from up to 12 child
input links, and returns a double-precision floating-point result. The
expression is evaluated by the EPICS Calc engine, and the result is returned as
the value of the link.
Two additional expressions may also be provided and are evaluated to determine
whether the record owning the link should be placed in alarm state. In both
cases the result of the main calculation is available to these expressions as
C<VAL> (attempts to assign to C<VAL> inside either expression will have no
lasting effect). If the C<major> expression evaluates to a non-zero value the
record will be placed in C<LINK/MAJOR> alarm. If not and the C<minor> expression
evaluates to non-zero the record will be placed in C<LINK/MINOR> alarm state.
A calculation link can also be an output link, with the scalar output value
being converted to a double and provided to the expression as C<VAL>. Up to 12
additional input links can also be read and provided to the expression as above.
The result of the calculation is forwarded to a child output link specified in
the link's C<out> parameter.
For an output link the main expression is actually optional; if not provided the
converted value will be forwarded to the output link unchanged. The two alarm
expressions may still be used to put the output link into alarm state as
described above.
=head4 Parameters
@@ -94,6 +114,7 @@ The link address is a JSON map with the following keys:
=item expr
The primary expression to be evaluated, given as a string.
This is optional for output links, required for input links.
=item major
@@ -110,6 +131,12 @@ to the inputs C<A>, C<B>, C<C>, ... C<L>. Each input argument may be either a
numeric literal or an embedded JSON link inside C<{}> braces. The same input
values are provided to the two alarm expressions as to the primary expression.
=item out
A JSON link inside C<{}> braces which specifies the destination of C<putValue>
operations after any expressions have been evaluated.
This key is required for output links, not used by input links.
=item units
An optional string specifying the engineering units for the result of the

168
src/std/link/lnkCalc.c
View File

@@ -6,13 +6,9 @@
\*************************************************************************/
/* lnkCalc.c */
/* Current usage
* {calc:{expr:"A", args:[{...}, ...]}}
/* Usage
* {calc:{expr:"A*B", args:[{...}, ...], units:"mm"}}
* First link in 'args' is 'A', second is 'B', and so forth.
*
* TODO:
* Support setting individual input links instead of the args list.
* {calc:{expr:"K", K:{...}}}
*/
#include <string.h>
@@ -49,10 +45,11 @@ epicsExportAddress(int, lnkCalc_debug);
typedef struct calc_link {
jlink jlink; /* embedded object */
int nArgs;
short dbfType;
enum {
ps_init,
ps_expr, ps_major, ps_minor,
ps_args,
ps_args, ps_out,
ps_prec,
ps_units,
ps_time,
@@ -70,6 +67,7 @@ typedef struct calc_link {
char *units;
short tinp;
struct link inp[CALCPERFORM_NARGS];
struct link out;
double arg[CALCPERFORM_NARGS];
epicsTimeStamp time;
double val;
@@ -87,8 +85,8 @@ static jlink* lnkCalc_alloc(short dbfType)
IFDEBUG(10)
printf("lnkCalc_alloc(%d)\n", dbfType);
if (dbfType != DBF_INLINK) {
errlogPrintf("lnkCalc: Only works with input links\n");
if (dbfType == DBF_FWDLINK) {
errlogPrintf("lnkCalc: No support for forward links\n");
return NULL;
}
@@ -99,6 +97,7 @@ static jlink* lnkCalc_alloc(short dbfType)
}
clink->nArgs = 0;
clink->dbfType = dbfType;
clink->pstate = ps_init;
clink->prec = 15; /* standard value for a double */
clink->tinp = -1;
@@ -120,6 +119,8 @@ static void lnkCalc_free(jlink *pjlink)
for (i = 0; i < clink->nArgs; i++)
dbJLinkFree(clink->inp[i].value.json.jlink);
dbJLinkFree(clink->out.value.json.jlink);
free(clink->expr);
free(clink->major);
free(clink->minor);
@@ -253,7 +254,7 @@ static jlif_key_result lnkCalc_start_map(jlink *pjlink)
IFDEBUG(10)
printf("lnkCalc_start_map(calc@%p)\n", clink);
if (clink->pstate == ps_args)
if (clink->pstate == ps_args || clink->pstate == ps_out)
return jlif_key_child_link;
if (clink->pstate != ps_init) {
@@ -271,7 +272,21 @@ static jlif_result lnkCalc_map_key(jlink *pjlink, const char *key, size_t len)
IFDEBUG(10)
printf("lnkCalc_map_key(calc@%p, \"%.*s\")\n", pjlink, (int) len, key);
if (len == 4) {
/* FIXME: These errors messages are wrong when a key is duplicated.
* The key is known, we just don't allow it more than once.
*/
if (len == 3) {
if (!strncmp(key, "out", len) &&
clink->dbfType == DBF_OUTLINK &&
clink->out.type == 0)
clink->pstate = ps_out;
else {
errlogPrintf("lnkCalc: Unknown key \"%.3s\"\n", key);
return jlif_stop;
}
}
else if (len == 4) {
if (!strncmp(key, "expr", len) && !clink->post_expr)
clink->pstate = ps_expr;
else if (!strncmp(key, "args", len) && !clink->nArgs)
@@ -314,8 +329,14 @@ static jlif_result lnkCalc_end_map(jlink *pjlink)
if (clink->pstate == ps_error)
return jlif_stop;
else if (!clink->post_expr) {
errlogPrintf("lnkCalc: no expression ('expr' key)\n");
else if (clink->dbfType == DBF_INLINK &&
!clink->post_expr) {
errlogPrintf("lnkCalc: No expression ('expr' key)\n");
return jlif_stop;
}
else if (clink->dbfType == DBF_OUTLINK &&
clink->out.type != JSON_LINK) {
errlogPrintf("lnkCalc: No output link ('out' key)\n");
return jlif_stop;
}
@@ -355,15 +376,27 @@ static void lnkCalc_end_child(jlink *parent, jlink *child)
calc_link *clink = CONTAINER(parent, struct calc_link, jlink);
struct link *plink;
if (clink->nArgs == CALCPERFORM_NARGS) {
dbJLinkFree(child);
errlogPrintf("lnkCalc: Too many input args, limit is %d\n",
CALCPERFORM_NARGS);
if (clink->pstate == ps_args) {
if (clink->nArgs == CALCPERFORM_NARGS) {
errlogPrintf("lnkCalc: Too many input args, limit is %d\n",
CALCPERFORM_NARGS);
goto errOut;
}
plink = &clink->inp[clink->nArgs++];
}
else if (clink->pstate == ps_out) {
plink = &clink->out;
}
else {
errlogPrintf("lnkCalc: Unexpected child link, parser state = %d\n",
clink->pstate);
errOut:
clink->pstate = ps_error;
dbJLinkFree(child);
return;
}
plink = &clink->inp[clink->nArgs++];
plink->type = JSON_LINK;
plink->value.json.string = NULL;
plink->value.json.jlink = child;
@@ -421,6 +454,12 @@ static void lnkCalc_report(const jlink *pjlink, int level, int indent)
if (child)
dbJLinkReport(child, level - 1, indent + 4);
}
if (clink->out.type == JSON_LINK) {
printf("%*s Output:\n", indent, "");
dbJLinkReport(clink->out.value.json.jlink, level - 1, indent + 4);
}
}
}
@@ -439,6 +478,10 @@ long lnkCalc_map_children(jlink *pjlink, jlink_map_fn rtn, void *ctx)
if (status)
return status;
}
if (clink->out.type == JSON_LINK) {
return dbJLinkMapChildren(&clink->out, rtn, ctx);
}
return 0;
}
@@ -460,6 +503,10 @@ static void lnkCalc_open(struct link *plink)
dbJLinkInit(child);
dbLoadLink(child, DBR_DOUBLE, &clink->arg[i]);
}
if (clink->out.type == JSON_LINK) {
dbJLinkInit(&clink->out);
}
}
static void lnkCalc_remove(struct dbLocker *locker, struct link *plink)
@@ -477,6 +524,10 @@ static void lnkCalc_remove(struct dbLocker *locker, struct link *plink)
dbRemoveLink(locker, child);
}
if (clink->out.type == JSON_LINK) {
dbRemoveLink(locker, &clink->out);
}
free(clink->expr);
free(clink->major);
free(clink->minor);
@@ -506,6 +557,14 @@ static int lnkCalc_isConn(const struct link *plink)
connected = 0;
}
if (clink->out.type == JSON_LINK) {
struct link *child = &clink->out;
if (dbLinkIsVolatile(child) &&
!dbIsLinkConnected(child))
connected = 0;
}
return connected;
}
@@ -626,6 +685,77 @@ static long lnkCalc_getValue(struct link *plink, short dbrType, void *pbuffer,
return status;
}
static long lnkCalc_putValue(struct link *plink, short dbrType,
const void *pbuffer, long nRequest)
{
calc_link *clink = CONTAINER(plink->value.json.jlink,
struct calc_link, jlink);
dbCommon *prec = plink->precord;
int i;
long status;
FASTCONVERT conv = dbFastGetConvertRoutine[dbrType][DBR_DOUBLE];
IFDEBUG(10)
printf("lnkCalc_putValue(calc@%p, %d, ...)\n", clink, dbrType);
/* Any link errors will trigger a LINK/INVALID alarm in the child link */
for (i = 0; i < clink->nArgs; i++) {
struct link *child = &clink->inp[i];
long nReq = 1;
if (i == clink->tinp) {
struct lcvt vt = {&clink->arg[i], &clink->time};
status = dbLinkDoLocked(child, readLocked, &vt);
if (status == S_db_noLSET)
status = readLocked(child, &vt);
if (dbLinkIsConstant(&prec->tsel) &&
prec->tse == epicsTimeEventDeviceTime) {
prec->time = clink->time;
}
}
else
dbGetLink(child, DBR_DOUBLE, &clink->arg[i], NULL, &nReq);
}
clink->stat = 0;
clink->sevr = 0;
/* Get the value being output as VAL */
status = conv(pbuffer, &clink->val, NULL);
if (!status && clink->post_expr)
status = calcPerform(clink->arg, &clink->val, clink->post_expr);
if (!status && clink->post_major) {
double alval = clink->val;
status = calcPerform(clink->arg, &alval, clink->post_major);
if (!status && alval) {
clink->stat = LINK_ALARM;
clink->sevr = MAJOR_ALARM;
recGblSetSevr(prec, clink->stat, clink->sevr);
}
}
if (!status && clink->post_minor) {
double alval = clink->val;
status = calcPerform(clink->arg, &alval, clink->post_minor);
if (!status && alval) {
clink->stat = LINK_ALARM;
clink->sevr = MINOR_ALARM;
recGblSetSevr(prec, clink->stat, clink->sevr);
}
}
if (!status) {
status = dbPutLink(&clink->out, DBR_DOUBLE, &clink->val, 1);
}
return status;
}
static long lnkCalc_getPrecision(const struct link *plink, short *precision)
{
calc_link *clink = CONTAINER(plink->value.json.jlink,
@@ -705,7 +835,7 @@ static lset lnkCalc_lset = {
NULL, NULL, NULL,
lnkCalc_getPrecision, lnkCalc_getUnits,
lnkCalc_getAlarm, lnkCalc_getTimestamp,
NULL, NULL,
lnkCalc_putValue, NULL,
NULL, doLocked
};