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AK: Add a StringView method to count the number of lines in a string
We already have a helper to split a StringView by line while considering "\n", "\r", and "\r\n". Add an analagous method to just count the number of lines in the same manner.
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parent
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commit
82ea53cf10
Notes:
sideshowbarker
2024-07-17 01:10:58 +09:00
Author: https://github.com/trflynn89 Commit: https://github.com/SerenityOS/serenity/commit/82ea53cf10 Pull-request: https://github.com/SerenityOS/serenity/pull/23525 Reviewed-by: https://github.com/LucasChollet ✅
@ -68,6 +68,48 @@ Vector<StringView> StringView::split_view(StringView separator, SplitBehavior sp
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return parts;
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}
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template<typename Callback>
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static void for_each_line(StringView string, Callback&& callback)
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{
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char const* characters = string.characters_without_null_termination();
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size_t substart = 0;
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bool last_ch_was_cr = false;
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for (size_t i = 0; i < string.length(); ++i) {
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char ch = characters[i];
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bool split_view = false;
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switch (ch) {
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case '\n':
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if (last_ch_was_cr)
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substart = i + 1;
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else
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split_view = true;
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last_ch_was_cr = false;
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break;
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case '\r':
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split_view = true;
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last_ch_was_cr = true;
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break;
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default:
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last_ch_was_cr = false;
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break;
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}
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if (split_view) {
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callback(string.substring_view(substart, i - substart));
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substart = i + 1;
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}
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}
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if (size_t taillen = string.length() - substart; taillen != 0)
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callback(string.substring_view(substart, taillen));
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}
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Vector<StringView> StringView::lines(ConsiderCarriageReturn consider_carriage_return) const
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{
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if (is_empty())
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@ -76,36 +118,24 @@ Vector<StringView> StringView::lines(ConsiderCarriageReturn consider_carriage_re
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if (consider_carriage_return == ConsiderCarriageReturn::No)
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return split_view('\n', SplitBehavior::KeepEmpty);
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Vector<StringView> v;
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size_t substart = 0;
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bool last_ch_was_cr = false;
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bool split_view = false;
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for (size_t i = 0; i < length(); ++i) {
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char ch = characters_without_null_termination()[i];
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if (ch == '\n') {
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split_view = true;
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if (last_ch_was_cr) {
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substart = i + 1;
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split_view = false;
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}
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}
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if (ch == '\r') {
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split_view = true;
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last_ch_was_cr = true;
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} else {
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last_ch_was_cr = false;
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}
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if (split_view) {
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size_t sublen = i - substart;
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v.append(substring_view(substart, sublen));
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substart = i + 1;
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}
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split_view = false;
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}
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size_t taillen = length() - substart;
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if (taillen != 0)
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v.append(substring_view(substart, taillen));
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return v;
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Vector<StringView> lines;
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for_each_line(*this, [&](auto line) { lines.append(line); });
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return lines;
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}
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size_t StringView::count_lines(ConsiderCarriageReturn consider_carriage_return) const
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{
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if (is_empty())
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return 1;
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if (consider_carriage_return == ConsiderCarriageReturn::No)
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return count('\n') + 1;
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size_t lines = 0;
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for_each_line(*this, [&](auto) { ++lines; });
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return lines;
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}
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bool StringView::starts_with(char ch) const
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@ -240,6 +240,7 @@ public:
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Yes,
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};
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[[nodiscard]] Vector<StringView> lines(ConsiderCarriageReturn = ConsiderCarriageReturn::Yes) const;
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[[nodiscard]] size_t count_lines(ConsiderCarriageReturn = ConsiderCarriageReturn::Yes) const;
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// Create a new substring view of this string view, starting either at the beginning of
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// the given substring view, or after its end, and continuing until the end of this string
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@ -105,6 +105,24 @@ TEST_CASE(lines)
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EXPECT_EQ(test_string_vector.at(2).is_empty(), true);
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}
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TEST_CASE(count_lines)
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{
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EXPECT_EQ(""sv.count_lines(), 1u);
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EXPECT_EQ("foo"sv.count_lines(), 1u);
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EXPECT_EQ("foo\nbar"sv.count_lines(), 2u);
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EXPECT_EQ("foo\rbar"sv.count_lines(), 2u);
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EXPECT_EQ("foo\rbar"sv.count_lines(StringView::ConsiderCarriageReturn::No), 1u);
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EXPECT_EQ("foo\r\nbar"sv.count_lines(), 2u);
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EXPECT_EQ("foo\r\nbar"sv.count_lines(StringView::ConsiderCarriageReturn::No), 2u);
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EXPECT_EQ("foo\nbar\nbax"sv.count_lines(), 3u);
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EXPECT_EQ("foo\rbar\rbaz"sv.count_lines(), 3u);
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EXPECT_EQ("foo\rbar\rbaz"sv.count_lines(StringView::ConsiderCarriageReturn::No), 1u);
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EXPECT_EQ("foo\r\nbar\r\nbaz"sv.count_lines(), 3u);
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EXPECT_EQ("foo\r\nbar\r\nbaz"sv.count_lines(StringView::ConsiderCarriageReturn::No), 3u);
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}
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TEST_CASE(find)
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{
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auto test_string_view = "aabbcc_xy_ccbbaa"sv;
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