From 33be7e6c6881545f9ce2c284b42788fc8c1ee79c Mon Sep 17 00:00:00 2001
From: Harpreet Sangar <happy_san@protonmail.com>
Date: Tue, 25 Apr 2023 09:39:51 +0530
Subject: [PATCH] Add `ArrayUtils::skip_index_to_id`.

---
 include/array_utils.h            |  6 ++++++
 include/filter_result_iterator.h |  2 +-
 src/array_utils.cpp              | 25 +++++++++++++++++++++++++
 src/filter_result_iterator.cpp   | 16 ++++------------
 src/index.cpp                    |  2 +-
 5 files changed, 37 insertions(+), 14 deletions(-)

diff --git a/include/array_utils.h b/include/array_utils.h
index 81a0576c..008a8a36 100644
--- a/include/array_utils.h
+++ b/include/array_utils.h
@@ -16,4 +16,10 @@ public:
 
   static size_t exclude_scalar(const uint32_t *src, const size_t lenSrc, const uint32_t *filter, const size_t lenFilter,
                               uint32_t **out);
+
+  /// Performs binary search to find the index of id. If id is not found, curr_index is set to the index of next bigger
+  /// number than id in the array.
+  /// \return Whether or not id was found in array.
+  static bool skip_index_to_id(uint32_t& curr_index, uint32_t const* const array, const uint32_t& array_len,
+                               const uint32_t& id);
 };
\ No newline at end of file
diff --git a/include/filter_result_iterator.h b/include/filter_result_iterator.h
index 2e30a2cb..259b93f0 100644
--- a/include/filter_result_iterator.h
+++ b/include/filter_result_iterator.h
@@ -172,7 +172,7 @@ public:
     /// Collects n doc ids while advancing the iterator. The ids present in excluded_result_ids are ignored. The
     /// iterator may become invalid during this operation.
     void get_n_ids(const uint32_t &n,
-                   size_t& excluded_result_index,
+                   uint32_t& excluded_result_index,
                    uint32_t const* const excluded_result_ids, const size_t& excluded_result_ids_size,
                    std::vector<uint32_t> &results);
 
diff --git a/src/array_utils.cpp b/src/array_utils.cpp
index 9f0c7f4a..ad22a85f 100644
--- a/src/array_utils.cpp
+++ b/src/array_utils.cpp
@@ -149,4 +149,29 @@ size_t ArrayUtils::exclude_scalar(const uint32_t *A, const size_t lenA,
   delete[] results;
 
   return res_index;
+}
+
+bool ArrayUtils::skip_index_to_id(uint32_t& curr_index, uint32_t const* const array, const uint32_t& array_len,
+                                  const uint32_t& id) {
+    if (id <= array[curr_index]) {
+        return id == array[curr_index];
+    }
+
+    long start = curr_index, mid, end = array_len;
+
+    while (start <= end) {
+        mid =  start + (end - start) / 2;
+
+        if (array[mid] == id) {
+            curr_index = mid;
+            return true;
+        } else if (array[mid] < id) {
+            start = mid + 1;
+        } else {
+            end = mid - 1;
+        }
+    }
+
+    curr_index = start;
+    return false;
 }
\ No newline at end of file
diff --git a/src/filter_result_iterator.cpp b/src/filter_result_iterator.cpp
index 9977c6be..63a76f73 100644
--- a/src/filter_result_iterator.cpp
+++ b/src/filter_result_iterator.cpp
@@ -959,7 +959,7 @@ void filter_result_iterator_t::skip_to(uint32_t id) {
     }
 
     if (is_filter_result_initialized) {
-        while (filter_result.docs[result_index] < id && ++result_index < filter_result.count);
+        ArrayUtils::skip_index_to_id(result_index, filter_result.docs, filter_result.count, id);
 
         if (result_index >= filter_result.count) {
             is_valid = false;
@@ -1348,7 +1348,7 @@ void filter_result_iterator_t::get_n_ids(const uint32_t& n, std::vector<uint32_t
 }
 
 void filter_result_iterator_t::get_n_ids(const uint32_t& n,
-                                         size_t& excluded_result_index,
+                                         uint32_t & excluded_result_index,
                                          uint32_t const* const excluded_result_ids, const size_t& excluded_result_ids_size,
                                          std::vector<uint32_t>& results) {
     if (excluded_result_ids == nullptr || excluded_result_ids_size == 0 ||
@@ -1360,11 +1360,7 @@ void filter_result_iterator_t::get_n_ids(const uint32_t& n,
         for (uint32_t count = 0; count < n && result_index < filter_result.count;) {
             auto id = filter_result.docs[result_index++];
 
-            while (excluded_result_index < excluded_result_ids_size && excluded_result_ids[excluded_result_index] < id) {
-                excluded_result_index++;
-            }
-
-            if (excluded_result_index >= excluded_result_ids_size || excluded_result_ids[excluded_result_index] != id) {
+            if (!ArrayUtils::skip_index_to_id(excluded_result_index, excluded_result_ids, excluded_result_ids_size, id)) {
                 results.push_back(id);
                 count++;
             }
@@ -1375,11 +1371,7 @@ void filter_result_iterator_t::get_n_ids(const uint32_t& n,
     }
 
     for (uint32_t count = 0; count < n && is_valid;) {
-        while (excluded_result_index < excluded_result_ids_size && excluded_result_ids[excluded_result_index] < seq_id) {
-            excluded_result_index++;
-        }
-
-        if (excluded_result_index >= excluded_result_ids_size || excluded_result_ids[excluded_result_index] != seq_id) {
+        if (!ArrayUtils::skip_index_to_id(excluded_result_index, excluded_result_ids, excluded_result_ids_size, seq_id)) {
             results.push_back(seq_id);
             count++;
         }
diff --git a/src/index.cpp b/src/index.cpp
index ba405b53..225a7b7b 100644
--- a/src/index.cpp
+++ b/src/index.cpp
@@ -4966,7 +4966,7 @@ void Index::search_wildcard(filter_node_t const* const& filter_tree_root,
     const auto parent_search_begin = search_begin_us;
     const auto parent_search_stop_ms = search_stop_us;
     auto parent_search_cutoff = search_cutoff;
-    size_t excluded_result_index = 0;
+    uint32_t excluded_result_index = 0;
 
     for(size_t thread_id = 0; thread_id < num_threads && filter_result_iterator.is_valid; thread_id++) {
         std::vector<uint32_t> batch_result_ids;