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AK: Add a method to create a String with a repeated code point

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Timothy Flynn 2023-01-22 10:17:48 -05:00 • committed by Tim Flynn
parent d50724956e
commit 427b82065c
3 changed files with 120 additions and 0 deletions
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39
AK/String.cpp
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@ -4,6 +4,7 @@
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Array.h>
#include <AK/Checked.h>
#include <AK/FlyString.h>
#include <AK/Format.h>
@ -221,6 +222,44 @@ ErrorOr<String> String::from_utf8(StringView view)
return String { move(data) };
}
ErrorOr<String> String::repeated(u32 code_point, size_t count)
{
VERIFY(is_unicode(code_point));
Array<u8, 4> code_point_as_utf8;
size_t i = 0;
size_t code_point_byte_length = UnicodeUtils::code_point_to_utf8(code_point, [&](auto byte) {
code_point_as_utf8[i++] = static_cast<u8>(byte);
});
auto copy_to_buffer = [&](u8* buffer) {
if (code_point_byte_length == 1) {
memset(buffer, code_point_as_utf8[0], count);
return;
}
for (i = 0; i < count; ++i)
memcpy(buffer + (i * code_point_byte_length), code_point_as_utf8.data(), code_point_byte_length);
};
auto total_byte_count = code_point_byte_length * count;
if (total_byte_count <= MAX_SHORT_STRING_BYTE_COUNT) {
ShortString short_string;
copy_to_buffer(short_string.storage);
short_string.byte_count_and_short_string_flag = (total_byte_count << 1) | SHORT_STRING_FLAG;
return String { short_string };
}
u8* buffer = nullptr;
auto new_string_data = TRY(Detail::StringData::create_uninitialized(total_byte_count, buffer));
copy_to_buffer(buffer);
return String { move(new_string_data) };
}
StringView String::bytes_as_string_view() const
{
return StringView(bytes());