adds working FST reader implementation

plugins/com.minres.scviewer.database.fst/csrc/fst/fst_helper.c

@@ -0,0 +1,31 @@
+#include "fstapi.h"
+
+int getHierType(struct fstHier * hier){
+	return hier->htyp;
+}
+
+void getHierScope(struct fstHier* h, struct fstHierScope* scope){
+	if(h->htyp==FST_HT_SCOPE)
+		*scope=h->u.scope;
+}
+
+void getHierVar(struct fstHier* h, struct fstHierVar* var){
+	if(h->htyp==FST_HT_VAR)
+		*var=h->u.var;
+}
+
+void getHierAttr(struct fstHier* h, struct fstHierAttr* attr){
+	if(h->htyp==FST_HT_ATTRBEGIN)
+		*attr=h->u.attr;
+}
+
+typedef void (*value_change_callback)(uint64_t time, fstHandle facidx, const char *value);
+
+static void forward_cb(void *user_callback_data_pointer, uint64_t time, fstHandle facidx, const unsigned char *value) {
+	//fprintf(stderr, "val: %s @ %ld\n", value, time);
+	((value_change_callback)user_callback_data_pointer)(time, facidx, value);
+}
+
+void iterateValueChanges(void* ctx, value_change_callback vcc) {
+	fstReaderIterBlocks(ctx, forward_cb, vcc, NULL);
+}