From f88ea12bacf381ad4f39ba2328c806e772c0dda8 Mon Sep 17 00:00:00 2001
From: William Wilgus <wilgus.william@gmail.com>
Date: Tue, 1 Mar 2022 22:37:11 -0500
Subject: [PATCH] tagcache compress uniqbuf 2 16-bit indices occupy a single 32
 bit slot

a lot of space is wasted when file indices less than 65535
entries should be more than 1 byte apart so use the LSB as a flag
when indices are > 65535 set flag to 0 and proceed as before

explicitly mark uniqbuf as 32bit

Change-Id: I54e06c152c369eb6c0322186fe2c1e9a1e6d940d
---
 apps/tagcache.c | 60 ++++++++++++++++++++++++++++++++++++++++++++-----
 apps/tagcache.h |  2 +-
 apps/tagtree.c  |  2 +-
 3 files changed, 56 insertions(+), 8 deletions(-)

diff --git a/apps/tagcache.c b/apps/tagcache.c
index 248e57237d..d09ddf486a 100644
--- a/apps/tagcache.c
+++ b/apps/tagcache.c
@@ -1209,7 +1209,7 @@ bool tagcache_check_clauses(struct tagcache_search *tcs,
     return check_clauses(tcs, &idx, clause, count);
 }
 
-static bool add_uniqbuf(struct tagcache_search *tcs, unsigned long id)
+static bool add_uniqbuf(struct tagcache_search *tcs, uint32_t id)
 {
     int i;
 
@@ -1220,11 +1220,53 @@ static bool add_uniqbuf(struct tagcache_search *tcs, unsigned long id)
         return true;
     }
 
-    for (i = 0; i < tcs->unique_list_count; i++)
+    if (id <= UINT16_MAX)
     {
-        /* Return false if entry is found. */
-        if (tcs->unique_list[i] == id)
-            return false;
+        /* place two 16-bit entries in a single 32-bit slot */
+        uint32_t idtmp;
+        union uentry{
+            uint16_t u16[2];
+            uint32_t u32;
+        } *entry;
+        id |= 1; /*odd - flag 16-bit entry */
+        for (i = 0; i < tcs->unique_list_count; i++)
+        {
+            entry = (union uentry *) &tcs->unique_list[i];
+            if ((entry->u32 & 1) == 0) /* contains a 32-bit entry */
+                continue;
+
+            /* Return false if entry is found. */
+            if (entry->u16[0] == id || entry->u16[1] == id)
+            {
+                logf("%d Exists (16) @ %d", id, i);
+                return false;
+            }
+  
+            if (entry->u16[1] == 0 && (entry->u16[0] & 1) == 1)
+            {
+                entry->u16[1] = id & UINT16_MAX;
+                return true; /*no more 16bit entries add to empty 16bit slot */
+            }
+
+        }
+        /* Not Found and no empty slot add a new entry */
+        entry = (union uentry *) &idtmp;
+        entry->u16[1] = 0;
+        entry->u16[0] = id & UINT16_MAX;
+        id = idtmp;
+    }
+    else
+    {
+        id &= ~1; /* even - flag 32-bit entry */
+        for (i = 0; i < tcs->unique_list_count; i++)
+        {
+            /* Return false if entry is found. */
+            if (tcs->unique_list[i] == id)
+            {
+                logf("%d Exists (32)@ %d", id, i);
+                return false;
+            }
+        }
     }
 
     if (tcs->unique_list_count < tcs->unique_list_capacity)
@@ -1470,9 +1512,10 @@ bool tagcache_search(struct tagcache_search *tcs, int tag)
 void tagcache_search_set_uniqbuf(struct tagcache_search *tcs,
                                  void *buffer, long length)
 {
-    tcs->unique_list = (unsigned long *)buffer;
+    tcs->unique_list = (uint32_t *)buffer;
     tcs->unique_list_capacity = length / sizeof(*tcs->unique_list);
     tcs->unique_list_count = 0;
+    memset(tcs->unique_list, 0, tcs->unique_list_capacity);
 }
 
 bool tagcache_search_add_filter(struct tagcache_search *tcs,
@@ -1702,6 +1745,11 @@ bool tagcache_get_next(struct tagcache_search *tcs)
             return true;
     }
 
+#ifdef LOGF_ENABLE
+    if (tcs->unique_list_count > 0)
+        logf(" uniqbuf: %d used / %d avail", tcs->unique_list_count, tcs->unique_list_capacity);
+#endif
+
     return false;
 }
 
diff --git a/apps/tagcache.h b/apps/tagcache.h
index 52a9283e35..b7c4aadbb1 100644
--- a/apps/tagcache.h
+++ b/apps/tagcache.h
@@ -188,7 +188,7 @@ struct tagcache_search {
     int entry_count;
     bool valid;
     bool initialized;
-    unsigned long *unique_list;
+    uint32_t *unique_list;
     int unique_list_capacity;
     int unique_list_count;
 
diff --git a/apps/tagtree.c b/apps/tagtree.c
index 9684d5424c..48ef1e28ce 100644
--- a/apps/tagtree.c
+++ b/apps/tagtree.c
@@ -111,7 +111,7 @@ enum variables {
 
 /* Capacity 10 000 entries (for example 10k different artists) */
 #define UNIQBUF_SIZE (64*1024)
-static long uniqbuf[UNIQBUF_SIZE / sizeof(long)];
+static uint32_t uniqbuf[UNIQBUF_SIZE / sizeof(uint32_t)];
 
 #define MAX_TAGS 5
 #define MAX_MENU_ID_SIZE 32