[coding] Add StringUtf8Multilang::RemoveString.

coding/coding_tests/string_utf8_multilang_tests.cpp

@@ -194,3 +194,61 @@ UNIT_TEST(MultilangString_ForEachLanguage)
   TEST(!s.ForEachLanguage(corruptedLanguages, fn), ());
   TEST_EQUAL(testAccumulator.size(), 0, ());
 }
+
+UNIT_TEST(MultilangString_RemoveString)
+{
+  auto testRemove = [](vector<pair<uint8_t, string>> const & strings,
+                       set<uint8_t> const & codesToRemove) {
+    StringUtf8Multilang str;
+    for (auto const & s : strings)
+      str.AddString(s.first, s.second);
+
+    string tmp;
+    for (auto const & s : strings)
+    {
+      TEST(str.HasString(s.first), ());
+      TEST(str.GetString(s.first, tmp), ());
+      TEST_EQUAL(tmp, s.second, ());
+    }
+
+    for (auto c : codesToRemove)
+      str.RemoveString(c);
+
+    for (auto const & s : strings)
+    {
+      if (codesToRemove.find(s.first) == codesToRemove.end())
+      {
+        TEST(str.HasString(s.first), ());
+        TEST(str.GetString(s.first, tmp), ());
+        TEST_EQUAL(tmp, s.second, ());
+      }
+      else
+      {
+        TEST(!str.HasString(s.first), ());
+      }
+    }
+
+    // No extra languages or other data damage.
+    str.ForEach([&](uint8_t lang, auto const &) {
+      TEST(base::FindIf(strings, [&lang](auto const & s) { return s.first == lang; }) !=
+               strings.end(),
+           ());
+      TEST(codesToRemove.find(lang) == codesToRemove.end(), ());
+    });
+  };
+
+  vector<pair<uint8_t, string>> strings = {{0, "aaa"},
+                                           {1, "bbb"},
+                                           {2, "ccc"},
+                                           {9, "ddd"},
+                                           {17, "eee"},
+                                           {27, "fff"},
+                                           {37, "ggg"}};
+
+  testRemove(strings, {0});
+  testRemove(strings, {1});
+  testRemove(strings, {9, 27});
+  testRemove(strings, {37});
+  testRemove(strings, {0, 1, 2, 9, 17, 27, 37});
+  testRemove(strings, {39});
+}

coding/string_utf8_multilang.cpp

@@ -207,6 +207,25 @@ void StringUtf8Multilang::AddString(int8_t lang, string const & utf8s)
   m_s.insert(m_s.end(), utf8s.begin(), utf8s.end());
 }
 
+void StringUtf8Multilang::RemoveString(int8_t lang)
+{
+  size_t i = 0;
+  size_t const sz = m_s.size();
+
+  while (i < sz)
+  {
+    size_t const next = GetNextIndex(i);
+
+    if ((m_s[i] & 0x3F) == lang)
+    {
+      m_s.erase(i, next - i);
+      return;
+    }
+
+    i = next;
+  }
+}
+
 bool StringUtf8Multilang::GetString(int8_t lang, string & utf8s) const
 {
   if (!IsSupportedLangCode(lang))

coding/string_utf8_multilang.hpp

@@ -120,6 +120,14 @@ public:
       AddString(l, utf8s);
   }
 
+  void RemoveString(int8_t lang);
+  void RemoveString(std::string const & lang)
+  {
+    int8_t const l = GetLangIndex(lang);
+    if (l >= 0)
+      RemoveString(l);
+  }
+
   // Calls |fn| for each pair of |lang| and |utf8s| stored in this multilang string.
   template <typename Fn>
   void ForEach(Fn && fn) const