More correct cache maintenance (hopefully)

diff --git a/ThermoBeaconDisplay.ino b/ThermoBeaconDisplay.ino
index 63df5451b7a54723ec14dc6a546832a226ed56ba..550e5a00b7118ccee74a4832cb160716c3079e96 100644 (file)
--- a/ThermoBeaconDisplay.ino
+++ b/ThermoBeaconDisplay.ino
@@ -170,13 +170,16 @@ void updateCache(struct entry *newentry)
     struct elem *slots[SLOTS] = { NULL };
     struct elem *target = NULL;
     int pos = 0;
+    bool not_yet_placed = true;
 
     while (true) {
+       bool step_ahead = true;  // Omit advancing if an element was dropped
        bool at_the_end = !cur;
        if (pos < SLOTS)
            slots[pos] = cur;
        // First handle insertion because it _can_ happen with cur == NULL
-       if (at_the_end || cur->entry.rssi < newentry->rssi) {
+       if (not_yet_placed &&
+               (at_the_end || cur->entry.rssi < newentry->rssi)) {
            dbgOp(pos, "potentially insert", newentry,
                  "before", cur ? &(cur->entry) : NULL);
            if (cur && strcmp(cur->entry.addr, newentry->addr) == 0) {
@@ -184,18 +187,14 @@ void updateCache(struct entry *newentry)
                      "replacing", &(cur->entry));
                target = cur;
            } else {
-               if (target) {
-                   dbgOp(pos, "not inserting because update scheduled",
-                         newentry, "before", cur ? &(cur->entry) : NULL);
-               } else {
-                   dbgOp(pos, "really insert", newentry,
-                         "before", cur ? &(cur->entry) : NULL);
-                   (*cur_p) = (struct elem *) malloc(sizeof(struct elem));
-                   (*cur_p)->next = cur;
-                   (*cur_p)->age = 0;
-                   (*cur_p)->entry = *newentry;
-               }
+               dbgOp(pos, "really insert", newentry,
+                          "before", cur ? &(cur->entry) : NULL);
+               (*cur_p) = (struct elem *) malloc(sizeof(struct elem));
+               (*cur_p)->next = cur;
+               (*cur_p)->age = 0;
+               (*cur_p)->entry = *newentry;
            }
+            not_yet_placed = false;
        }
        if (at_the_end)
            break;
@@ -214,6 +213,7 @@ void updateCache(struct entry *newentry)
                    dbgOp(pos, "update instead of delete", &(cur->entry),
                          "already at the insersion point for", newentry);
                    target = cur;
+                   not_yet_placed = false;
                } else {
                    dbgOp(pos, "really delete", &(cur->entry), "", NULL);
                    (*cur_p) = cur->next;
@@ -221,14 +221,16 @@ void updateCache(struct entry *newentry)
                    cur = *cur_p;
                    if (pos < SLOTS)
                        slots[pos] = NULL;
-                   pos--;  // This may make it negative, but it will be bumped up next
+                   step_ahead = false;  // Don't advance in the list
                }
            }
        }
        // Proceed to the next element of the list
-       cur_p = &(cur->next);
-       cur = *cur_p;
-       pos++;
+       if (step_ahead) {
+           cur_p = &(cur->next);
+           cur = *cur_p;
+           pos++;
+       }
     }
     // Finished modifying the list, now display
     for (cur = head, pos = 0; pos < SLOTS;