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AK: Add a StringView method to count the number of lines in a string

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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.
This commit is contained in:
Timothy Flynn 2024-03-08 09:57:35 -05:00 • committed by Tim Flynn
parent 07a27b2ec0
commit 82ea53cf10
3 changed files with 79 additions and 30 deletions
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90
AK/StringView.cpp
View file

@ -68,6 +68,48 @@ Vector<StringView> StringView::split_view(StringView separator, SplitBehavior sp
return parts;
}
template<typename Callback>
static void for_each_line(StringView string, Callback&& callback)
{
char const* characters = string.characters_without_null_termination();
size_t substart = 0;
bool last_ch_was_cr = false;
for (size_t i = 0; i < string.length(); ++i) {
char ch = characters[i];
bool split_view = false;
switch (ch) {
case '\n':
if (last_ch_was_cr)
substart = i + 1;
else
split_view = true;
last_ch_was_cr = false;
break;
case '\r':
split_view = true;
last_ch_was_cr = true;
break;
default:
last_ch_was_cr = false;
break;
}
if (split_view) {
callback(string.substring_view(substart, i - substart));
substart = i + 1;
}
}
if (size_t taillen = string.length() - substart; taillen != 0)
callback(string.substring_view(substart, taillen));
}
Vector<StringView> StringView::lines(ConsiderCarriageReturn consider_carriage_return) const
{
if (is_empty())
@ -76,36 +118,24 @@ Vector<StringView> StringView::lines(ConsiderCarriageReturn consider_carriage_re
if (consider_carriage_return == ConsiderCarriageReturn::No)
return split_view('\n', SplitBehavior::KeepEmpty);
Vector<StringView> v;
size_t substart = 0;
bool last_ch_was_cr = false;
bool split_view = false;
for (size_t i = 0; i < length(); ++i) {
char ch = characters_without_null_termination()[i];
if (ch == '\n') {
split_view = true;
if (last_ch_was_cr) {
substart = i + 1;
split_view = false;
}
}
if (ch == '\r') {
split_view = true;
last_ch_was_cr = true;
} else {
last_ch_was_cr = false;
}
if (split_view) {
size_t sublen = i - substart;
v.append(substring_view(substart, sublen));
substart = i + 1;
}
split_view = false;
}
size_t taillen = length() - substart;
if (taillen != 0)
v.append(substring_view(substart, taillen));
return v;
Vector<StringView> lines;
for_each_line(*this, [&](auto line) { lines.append(line); });
return lines;
}
size_t StringView::count_lines(ConsiderCarriageReturn consider_carriage_return) const
{
if (is_empty())
return 1;
if (consider_carriage_return == ConsiderCarriageReturn::No)
return count('\n') + 1;
size_t lines = 0;
for_each_line(*this, [&](auto) { ++lines; });
return lines;
}
bool StringView::starts_with(char ch) const