Added loadLS routine to lset

The long string in/out records use a different initializer
for constant links. The new loadLS method allows a constant
link type to initialize such a long string field.

NB: This routine was added in the middle of the lset table.
Any external link support implementations must be adjusted.

src/ioc/db/dbCa.c

@@ -715,7 +715,7 @@ static void scanLinkOnce(dbCommon *prec, caLink *pca) {
 static lset dbCa_lset = {
     0, 1, /* not Constant, Volatile */
     dbCaRemoveLink,
-    NULL, NULL,
+    NULL, NULL, NULL,
     isConnected,
     getDBFtype, getElements,
     dbCaGetLink,

src/ioc/db/dbConstLink.c

@@ -69,6 +69,30 @@ static long dbConstLoadScalar(struct link *plink, short dbrType, void *pbuffer)
             (pstr, pbuffer, NULL);
 }
 
+static long dbConstLoadLS(struct link *plink, char *pbuffer, epicsUInt32 size,
+    epicsUInt32 *plen)
+{
+    const char *pstr = plink->value.constantStr;
+    size_t len;
+
+    if (!pstr)
+        return S_db_badField;
+    len = strlen(pstr);
+
+    /* FIXME This handles the common case, but not the general one... */
+    if (pstr[0] == '[' && pstr[1] == '"' &&
+        pstr[len-2] == '"' && pstr[len-1] == ']') {
+        pstr += 2;
+        len -= 4;
+    }
+    if (--size > len) size = len;
+
+    strncpy(pbuffer, pstr, size);
+    pbuffer[size] = 0;
+    *plen = (epicsUInt32) strlen(pbuffer) + 1;
+    return 0;
+}
+
 static long dbConstLoadArray(struct link *plink, short dbrType, void *pbuffer,
         long *pnReq)
 {
@@ -102,6 +126,7 @@ static lset dbConst_lset = {
     1, 0, /* Constant, not Volatile */
     NULL,
     dbConstLoadScalar,
+    dbConstLoadLS,
     dbConstLoadArray,
     NULL,
     NULL, dbConstGetNelements,

src/ioc/db/dbDbLink.c

@@ -338,7 +338,7 @@ static void dbDbScanFwdLink(struct link *plink)
 static lset dbDb_lset = {
     0, 0, /* not Constant, not Volatile */
     dbDbRemoveLink,
-    NULL, NULL,
+    NULL, NULL, NULL,
     dbDbIsConnected,
     dbDbGetDBFtype, dbDbGetElements,
     dbDbGetValue,

src/ioc/db/dbLink.c

@@ -206,6 +206,17 @@ long dbLoadLink(struct link *plink, short dbrType, void *pbuffer)
     return S_db_noLSET;
 }
 
+long dbLoadLinkLS(struct link *plink, char *pbuffer, epicsUInt32 size,
+    epicsUInt32 *plen)
+{
+    lset *plset = plink->lset;
+
+    if (plset && plset->loadLS)
+        return plset->loadLS(plink, pbuffer, size, plen);
+
+    return S_db_noLSET;
+}
+
 long dbLoadLinkArray(struct link *plink, short dbrType, void *pbuffer,
     long *pnRequest)
 {
@@ -400,20 +411,6 @@ void dbScanFwdLink(struct link *plink)
 
 /* Helper functions for long string support */
 
-long dbLoadLinkLS(struct link *plink, char *pbuffer, epicsUInt32 size,
-    epicsUInt32 *plen)
-{
-    if (plink->type == CONSTANT &&
-        plink->value.constantStr) {
-        strncpy(pbuffer, plink->value.constantStr, --size);
-        pbuffer[size] = 0;
-        *plen = (epicsUInt32) strlen(pbuffer) + 1;
-        return 0;
-    }
-
-    return S_db_noLSET;
-}
-
 long dbGetLinkLS(struct link *plink, char *pbuffer, epicsUInt32 size,
     epicsUInt32 *plen)
 {

src/ioc/db/dbLink.h

@@ -37,6 +37,8 @@ typedef struct lset {
 
     /* Const init, data type hinting */
     long (*loadScalar)(struct link *plink, short dbrType, void *pbuffer);
+    long (*loadLS)(struct link *plink, char *pbuffer, epicsUInt32 size,
+            epicsUInt32 *plen);
     long (*loadArray)(struct link *plink, short dbrType, void *pbuffer,
             long *pnRequest);
 

src/std/link/lnkConst.c

@@ -341,6 +341,35 @@ static long lnkConst_loadScalar(struct link *plink, short dbrType, void *pbuffer
     return status;
 }
 
+static long lnkConst_loadLS(struct link *plink, char *pbuffer, epicsUInt32 size,
+    epicsUInt32 *plen)
+{
+    clink *clink = CONTAINER(plink->value.json.jlink, struct clink, jlink);
+    const char *pstr;
+
+    IFDEBUG(10)
+        printf("lnkConst_loadLS(const@%p, %p, %d, %d)\n",
+            clink, pbuffer, size, *plen);
+
+    switch (clink->type) {
+    case sc40:
+        pstr = clink->value.scalar_string;
+        break;
+
+    case ac40:
+        pstr = clink->value.pstrings[0];
+        break;
+
+    default:
+        return S_db_badField;
+    }
+
+    strncpy(pbuffer, pstr, --size);
+    pbuffer[size] = 0;
+    *plen = (epicsUInt32) strlen(pbuffer) + 1;
+    return 0;
+}
+
 static long lnkConst_loadArray(struct link *plink, short dbrType, void *pbuffer,
         long *pnReq)
 {
@@ -437,7 +466,7 @@ static long lnkConst_getValue(struct link *plink, short dbrType, void *pbuffer,
 
 static lset lnkConst_lset = {
     1, 0, /* Constant, not Volatile */
-    NULL, lnkConst_loadScalar, lnkConst_loadArray, NULL,
+    NULL, lnkConst_loadScalar, lnkConst_loadLS, lnkConst_loadArray, NULL,
     NULL, lnkConst_getNelements, lnkConst_getValue,
     NULL, NULL, NULL,
     NULL, NULL,