AK: Add case insensitive version of starts_with

lanmonster · Jul 20, 2020 · a5ecb9b · a5ecb9b
1 parent ccc929d
commit a5ecb9b
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Showing 11 changed files with 53 additions and 20 deletions.
diff --git a/AK/FlyString.cpp b/AK/FlyString.cpp
@@ -99,6 +99,11 @@ bool FlyString::equals_ignoring_case(const StringView& other) const
  return StringUtils::equals_ignoring_case(view(), other);
 }
 
+bool FlyString::starts_with(const StringView& str, CaseSensitivity case_sensitivity) const
+{
+ return StringUtils::starts_with(view(), str, case_sensitivity);
+}
+
 bool FlyString::ends_with(const StringView& str, CaseSensitivity case_sensitivity) const
 {
  return StringUtils::ends_with(view(), str, case_sensitivity);

diff --git a/AK/FlyString.h b/AK/FlyString.h
@@ -85,6 +85,7 @@ class FlyString {
  Optional<int> to_int() const;
 
  bool equals_ignoring_case(const StringView&) const;
+ bool starts_with(const StringView&, CaseSensitivity = CaseSensitivity::CaseSensitive) const;
  bool ends_with(const StringView&, CaseSensitivity = CaseSensitivity::CaseSensitive) const;
 
  static void did_destroy_impl(Badge<StringImpl>, StringImpl&);

diff --git a/AK/String.cpp b/AK/String.cpp
@@ -260,15 +260,9 @@ String String::format(const char* fmt, ...)
  return builder.to_string();
 }
 
-bool String::starts_with(const StringView& str) const
+bool String::starts_with(const StringView& str, CaseSensitivity case_sensitivity) const
 {
- if (str.is_empty())
- return true;
- if (is_empty())
- return false;
- if (str.length() > length())
- return false;
- return !memcmp(characters(), str.characters_without_null_termination(), str.length());
+ return StringUtils::starts_with(*this, str, case_sensitivity);
 }
 
 bool String::starts_with(char ch) const

diff --git a/AK/String.h b/AK/String.h
@@ -145,7 +145,7 @@ class String {
  ConstIterator begin() const { return characters(); }
  ConstIterator end() const { return begin() + length(); }
 
- bool starts_with(const StringView&) const;
+ bool starts_with(const StringView&, CaseSensitivity = CaseSensitivity::CaseSensitive) const;
  bool ends_with(const StringView&, CaseSensitivity = CaseSensitivity::CaseSensitive) const;
  bool starts_with(char) const;
  bool ends_with(char) const;

diff --git a/AK/StringUtils.cpp b/AK/StringUtils.cpp
@@ -202,6 +202,31 @@ bool ends_with(const StringView& str, const StringView& end, CaseSensitivity cas
  return true;
 }
 
+bool starts_with(const StringView& str, const StringView& start, CaseSensitivity case_sensitivity)
+{
+ if (start.is_empty())
+ return true;
+ if (str.is_empty())
+ return false;
+ if (start.length() > str.length())
+ return false;
+ if (str.characters_without_null_termination() == start.characters_without_null_termination())
+ return true;
+
+ if (case_sensitivity == CaseSensitivity::CaseSensitive)
+ return !memcmp(str.characters_without_null_termination(), start.characters_without_null_termination(), start.length());
+
+ auto str_chars = str.characters_without_null_termination();
+ auto start_chars = start.characters_without_null_termination();
+
+ size_t si = 0;
+ for (size_t starti = 0; starti < start.length(); ++si, ++starti) {
+ if (to_lowercase(str_chars[si]) != to_lowercase(start_chars[starti]))
+ return false;
+ }
+ return true;
+}
+
 }
 
 }
diff --git a/AK/StringUtils.h b/AK/StringUtils.h
@@ -44,6 +44,7 @@ Optional<unsigned> convert_to_uint(const StringView&);
 Optional<unsigned> convert_to_uint_from_hex(const StringView&);
 bool equals_ignoring_case(const StringView&, const StringView&);
 bool ends_with(const StringView& a, const StringView& b, CaseSensitivity);
+bool starts_with(const StringView&, const StringView&, CaseSensitivity);
 }
 
 }

diff --git a/AK/StringView.cpp b/AK/StringView.cpp
@@ -147,17 +147,9 @@ bool StringView::starts_with(char ch) const
  return ch == characters_without_null_termination()[0];
 }
 
-bool StringView::starts_with(const StringView& str) const
+bool StringView::starts_with(const StringView& str, CaseSensitivity case_sensitivity) const
 {
- if (str.is_empty())
- return true;
- if (is_empty())
- return false;
- if (str.length() > length())
- return false;
- if (characters_without_null_termination() == str.characters_without_null_termination())
- return true;
- return !memcmp(characters_without_null_termination(), str.characters_without_null_termination(), str.length());
+ return StringUtils::starts_with(*this, str, case_sensitivity);
 }
 
 bool StringView::ends_with(char ch) const

diff --git a/AK/StringView.h b/AK/StringView.h
@@ -72,7 +72,7 @@ class StringView {
 
  unsigned hash() const;
 
- bool starts_with(const StringView&) const;
+ bool starts_with(const StringView&, CaseSensitivity = CaseSensitivity::CaseSensitive) const;
  bool ends_with(const StringView&, CaseSensitivity = CaseSensitivity::CaseSensitive) const;
  bool starts_with(char) const;
  bool ends_with(char) const;

diff --git a/AK/Tests/TestString.cpp b/AK/Tests/TestString.cpp
@@ -87,6 +87,8 @@ TEST_CASE(starts_with)
  EXPECT(!test_string.starts_with('B'));
  EXPECT(test_string.starts_with("ABCDEF"));
  EXPECT(!test_string.starts_with("DEF"));
+ EXPECT(test_string.starts_with("abc", CaseSensitivity::CaseInsensitive));
+ EXPECT(!test_string.starts_with("abc", CaseSensitivity::CaseSensitive));
 }
 
 TEST_CASE(ends_with)

diff --git a/AK/Tests/TestStringUtils.cpp b/AK/Tests/TestStringUtils.cpp
@@ -164,4 +164,15 @@ TEST_CASE(ends_with)
  EXPECT(!AK::StringUtils::ends_with(test_string, "def", CaseSensitivity::CaseSensitive));
 }
 
+TEST_CASE(starts_with)
+{
+ String test_string = "ABCDEF";
+ EXPECT(AK::StringUtils::starts_with(test_string, "ABC", CaseSensitivity::CaseSensitive));
+ EXPECT(AK::StringUtils::starts_with(test_string, "ABCDEF", CaseSensitivity::CaseSensitive));
+ EXPECT(!AK::StringUtils::starts_with(test_string, "BCDEF", CaseSensitivity::CaseSensitive));
+ EXPECT(!AK::StringUtils::starts_with(test_string, "ABCDEFG", CaseSensitivity::CaseSensitive));
+ EXPECT(AK::StringUtils::starts_with(test_string, "abc", CaseSensitivity::CaseInsensitive));
+ EXPECT(!AK::StringUtils::starts_with(test_string, "abc", CaseSensitivity::CaseSensitive));
+}
+
 TEST_MAIN(StringUtils)
diff --git a/AK/Tests/TestStringView.cpp b/AK/Tests/TestStringView.cpp
@@ -68,6 +68,8 @@ TEST_CASE(starts_with)
  EXPECT(test_string_view.starts_with("AB"));
  EXPECT(test_string_view.starts_with("ABCDEF"));
  EXPECT(!test_string_view.starts_with("DEF"));
+ EXPECT(test_string_view.starts_with("abc", CaseSensitivity::CaseInsensitive));
+ EXPECT(!test_string_view.starts_with("abc", CaseSensitivity::CaseSensitive));
 }
 
 TEST_CASE(ends_with)