Replaced qsort by a lazy update of a bare-bones BST when using 'list'

src/sfxd.c

@@ -46,8 +46,13 @@ struct sfx_pool {
 
     float volume;
     float pitch_min, pitch_max;
+
+    int bst_parent, bst_left, bst_right;
+    bool inside_bst;
   } *sounds;
   int cap, use;
+
+  int bst_root;
 };
 
 ssize_t send_data(struct msg_target tgt, const void *data, ssize_t len);
@@ -69,7 +74,7 @@ struct sfx_pool_item *sfx_pool_load(const char *key, const char *path);
 
 struct ipc_data ipc = { 0 };
 struct audio_data audio = { 0 };
-struct sfx_pool sounds_pool = { 0, 0, 0 };
+struct sfx_pool sounds_pool = { 0, 0, 0, .bst_root = -1 };
 
 #ifndef NO_COUNTERS
 struct global_counters {
@@ -82,10 +87,80 @@ struct global_counters {
 } global_counters = { 0 };
 #endif
 
-static int qsort_compare_index_of_key(const void *p1, const void *p2) {
-  struct sfx_pool_item *it1 = &sounds_pool.sounds[*(int *)p1];
-  struct sfx_pool_item *it2 = &sounds_pool.sounds[*(int *)p2];
-  return strcmp(it1->key, it2->key);
+void sfx_pool_bst_insert(struct sfx_pool_item* lst, int *root_idx_ptr, int new_idx) {
+  // TODO balanced
+  struct sfx_pool_item *new_item = lst + new_idx;
+  int *new_idx_ptr = root_idx_ptr;
+  int parent_idx = -1;
+  int depth = 0;
+
+  int next_parent_idx;
+  while ((next_parent_idx = *new_idx_ptr) >= 0) {
+    depth++;
+    parent_idx = next_parent_idx;
+    struct sfx_pool_item *parent_item = lst + parent_idx;
+    if (strcmp(new_item->key, parent_item->key) < 0) {
+      new_idx_ptr = &parent_item->bst_left;
+    } else {
+      new_idx_ptr = &parent_item->bst_right;
+    }
+  }
+
+  *new_idx_ptr = new_idx;
+  new_item->bst_parent = parent_idx;
+  new_item->bst_left = -1;
+  new_item->bst_right = -1;
+  new_item->inside_bst = true;
+  send_txt((struct msg_target){ stdout, 0, 0, 0 }, "INF: Sorting element at index %d with key '%s' under the element at index %d with depth of %d\n", new_idx, lst[new_idx].key, parent_idx, depth);
+}
+
+// We don't need deletion support
+
+void sfx_pool_bst_insert_all(struct sfx_pool_item *lst, int *root_idx_ptr, int size) {
+  for (int i = 0; i < size; i++) {
+    if (!lst[i].inside_bst && lst[i].key[0] != '\0') {
+      sfx_pool_bst_insert(lst, root_idx_ptr, i);
+    }
+  }
+}
+
+int sfx_pool_bst_leftmost(const struct sfx_pool_item *lst, int parent_idx) {
+  if (parent_idx < 0) {
+    return parent_idx;
+  }
+
+  int next_idx;
+  while ((next_idx = lst[parent_idx].bst_left) >= 0) {
+    parent_idx = next_idx;
+  }
+  return parent_idx;
+}
+
+int sfx_pool_bst_go_right(const struct sfx_pool_item *lst, int cur_idx) {
+  if (cur_idx < 0) {
+    return cur_idx;
+  }
+  const struct sfx_pool_item *cur_item = lst + cur_idx;
+  if (cur_item->bst_right >= 0) {
+    return sfx_pool_bst_leftmost(lst, cur_item->bst_right);
+  }
+
+  while (true) {
+    int parent_idx = cur_item->bst_parent;
+    if (parent_idx < 0) {
+      // We are a root => end iterator
+      return parent_idx;
+    }
+
+    if (lst[parent_idx].bst_left == cur_idx) {
+      // We are a left child
+      return parent_idx;
+    }
+
+    // We are a right child
+    cur_idx = parent_idx;
+    cur_item = lst + cur_idx;
+  }
 }
 
 void usage(int argc, char **argv) {
@@ -331,18 +406,14 @@ void execute_command(struct msg_target tgt, const char *command, const char *par
       }
     }
   } else if (0 == strcmp(command, "list") || 0 == strcmp(command, "ls")) {
-    // TODO: find a better way to do this!
-    int *indices = calloc(sounds_pool.cap, sizeof(int));
-    for (int i = 0; i < sounds_pool.cap; i++) indices[i] = i;
-    qsort(indices, sounds_pool.cap, sizeof(int), qsort_compare_index_of_key);
-    for (int i = 0; i < sounds_pool.cap; i++) {
-      struct sfx_pool_item *item = &sounds_pool.sounds[indices[i]];
+    sfx_pool_bst_insert_all(sounds_pool.sounds, &sounds_pool.bst_root, sounds_pool.cap);
+    for (int i = sfx_pool_bst_leftmost(sounds_pool.sounds, sounds_pool.bst_root); i >= 0; i = sfx_pool_bst_go_right(sounds_pool.sounds, i)) {
+      struct sfx_pool_item *item = &sounds_pool.sounds[i];
       if (item->key[0] == '\0') continue;
       if (0 == fnmatch(params, item->key, 0) || strlen(params) == 0) {
         send_txt(tgt, "%s\n", item->key);
       }
     }
-    free(indices);
   } else if (0 == strcmp(command, "source")) {
     if (strlen(params) == 0) {
       send_txt(tgt, "ERR: argument required: PATH\n");