From feae2f1830befc7a672da601037d2fc445e0093b Mon Sep 17 00:00:00 2001
From: kampersanda <shnsk.knd@gmail.com>
Date: Sun, 10 Jul 2022 14:37:25 +0900
Subject: [PATCH] fix

---
 include/xcdat/tail_vector.hpp | 16 ++++++++++++----
 tests/test_trie.cpp           |  2 +-
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/include/xcdat/tail_vector.hpp b/include/xcdat/tail_vector.hpp
index 7212533..90c4f7c 100644
--- a/include/xcdat/tail_vector.hpp
+++ b/include/xcdat/tail_vector.hpp
@@ -168,17 +168,25 @@ class tail_vector {
 
     // Returns true if TAIL[tpos..epos] is a prefix of key, where epos is the end position of the tail.
     inline bool prefix_match(std::string_view key, std::uint64_t tpos) const {
-        assert(key.size() != 0);
+        if (tpos == 0) {
+            // suffix is empty, returns true always.
+            return true;
+        }
+        if (key.size() == 0) {
+            // When key is empty, returns true iff suffix is empty.
+            return false;
+        }
+
         std::uint64_t kpos = 0;
         if (bin_mode()) {
             do {
-                if (m_terms[tpos]) {
-                    return true;
-                }
                 if (key[kpos] != m_chars[tpos]) {
                     return false;
                 }
                 kpos += 1;
+                if (m_terms[tpos]) {
+                    return true;
+                }
                 tpos += 1;
             } while (kpos < key.size());
             return true;
diff --git a/tests/test_trie.cpp b/tests/test_trie.cpp
index f1f48ee..ac5a4a5 100644
--- a/tests/test_trie.cpp
+++ b/tests/test_trie.cpp
@@ -167,7 +167,7 @@ TEST_CASE("Test " TRIE_NAME " (tiny)") {
     test_basic_operations(trie, keys, others);
 
     {
-        auto itr = trie.make_prefix_iterator("MacBook_Pro");
+        auto itr = trie.make_prefix_iterator("MacBook_Pro_13inch");
         std::vector<std::string> expected = {"Mac", "MacBook", "MacBook_Pro"};
         for (const auto& exp : expected) {
             REQUIRE(itr.next());