AK: Add StringView::find_first/last_of

These methods search from the beginning or end of a string for the
first character in the input StringView and returns the position in
the string of the first match. Note that this is not a substring match.
Each comes with single char overloads for efficiency.
This commit is contained in:
Andrew Kaster 2020-05-02 12:21:20 -06:00 committed by Andreas Kling
parent 94c28552c6
commit 3eb3c2477f
Notes: sideshowbarker 2024-07-19 07:00:18 +09:00
3 changed files with 91 additions and 0 deletions

View file

@ -222,4 +222,46 @@ bool StringView::operator==(const String& string) const
return !__builtin_memcmp(m_characters, string.characters(), m_length);
}
Optional<size_t> StringView::find_first_of(char c) const
{
for (size_t pos = 0; pos < m_length; ++pos) {
if (m_characters[pos] == c)
return pos;
}
return {};
}
Optional<size_t> StringView::find_first_of(const StringView& view) const
{
for (size_t pos = 0; pos < m_length; ++pos) {
char c = m_characters[pos];
for (char view_char : view) {
if (c == view_char)
return pos;
}
}
return {};
}
Optional<size_t> StringView::find_last_of(char c) const
{
for (size_t pos = m_length; --pos >0;) {
if (m_characters[pos] == c)
return pos;
}
return {};
}
Optional<size_t> StringView::find_last_of(const StringView& view) const
{
for (size_t pos = m_length - 1; --pos > 0;) {
char c = m_characters[pos];
for (char view_char : view) {
if (c == view_char)
return pos;
}
}
return {};
}
}

View file

@ -79,6 +79,12 @@ public:
bool matches(const StringView& mask, CaseSensitivity = CaseSensitivity::CaseInsensitive) const;
bool contains(char) const;
Optional<size_t> find_first_of(char) const;
Optional<size_t> find_first_of(const StringView&) const;
Optional<size_t> find_last_of(char) const;
Optional<size_t> find_last_of(const StringView&) const;
StringView substring_view(size_t start, size_t length) const;
Vector<StringView> split_view(char, bool keep_empty = false) const;

View file

@ -111,4 +111,47 @@ TEST_CASE(lines)
EXPECT_EQ(test_string_vector.at(2).is_empty(), true);
}
TEST_CASE(find_first_of)
{
String test_string = "aabbcc_xy_ccbbaa";
StringView test_string_view = test_string.view();
EXPECT_EQ(test_string_view.find_first_of('b').has_value(), true);
EXPECT_EQ(test_string_view.find_first_of('b').value(), 2U);
EXPECT_EQ(test_string_view.find_first_of('_').has_value(), true);
EXPECT_EQ(test_string_view.find_first_of('_').value(), 6U);
EXPECT_EQ(test_string_view.find_first_of("bc").has_value(), true);
EXPECT_EQ(test_string_view.find_first_of("bc").value(), 2U);
EXPECT_EQ(test_string_view.find_first_of("yx").has_value(), true);
EXPECT_EQ(test_string_view.find_first_of("yx").value(), 7U);
EXPECT_EQ(test_string_view.find_first_of('n').has_value(), false);
EXPECT_EQ(test_string_view.find_first_of("defg").has_value(), false);
}
TEST_CASE(find_last_of)
{
String test_string = "aabbcc_xy_ccbbaa";
StringView test_string_view = test_string.view();
EXPECT_EQ(test_string_view.find_last_of('b').has_value(), true);
EXPECT_EQ(test_string_view.find_last_of('b').value(), 13U);
EXPECT_EQ(test_string_view.find_last_of('_').has_value(), true);
EXPECT_EQ(test_string_view.find_last_of('_').value(), 9U);
EXPECT_EQ(test_string_view.find_last_of("bc").has_value(), true);
EXPECT_EQ(test_string_view.find_last_of("bc").value(), 13U);
EXPECT_EQ(test_string_view.find_last_of("yx").has_value(), true);
EXPECT_EQ(test_string_view.find_last_of("yx").value(), 8U);
EXPECT_EQ(test_string_view.find_last_of('3').has_value(), false);
EXPECT_EQ(test_string_view.find_last_of("fghi").has_value(), false);
}
TEST_MAIN(StringView)