ladybird/AK/String.cpp
2023-03-13 15:16:20 +00:00

620 lines
18 KiB
C++

/*
* Copyright (c) 2018-2022, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Array.h>
#include <AK/Checked.h>
#include <AK/FlyString.h>
#include <AK/Format.h>
#include <AK/MemMem.h>
#include <AK/Stream.h>
#include <AK/String.h>
#include <AK/Vector.h>
#include <stdlib.h>
namespace AK {
namespace Detail {
class StringData final : public RefCounted<StringData> {
public:
static ErrorOr<NonnullRefPtr<StringData>> create_uninitialized(size_t, u8*& buffer);
static ErrorOr<NonnullRefPtr<StringData>> create_substring(StringData const& superstring, size_t start, size_t byte_count);
static ErrorOr<NonnullRefPtr<StringData>> from_utf8(char const* utf8_bytes, size_t);
static ErrorOr<NonnullRefPtr<StringData>> from_stream(Stream&, size_t byte_count);
struct SubstringData {
StringData const* superstring { nullptr };
u32 start_offset { 0 };
};
void operator delete(void* ptr);
~StringData();
SubstringData const& substring_data() const
{
return *reinterpret_cast<SubstringData const*>(m_bytes_or_substring_data);
}
// NOTE: There is no guarantee about null-termination.
ReadonlyBytes bytes() const
{
if (m_substring) {
auto const& data = substring_data();
return data.superstring->bytes().slice(data.start_offset, m_byte_count);
}
return { &m_bytes_or_substring_data[0], m_byte_count };
}
StringView bytes_as_string_view() const { return { bytes() }; }
bool operator==(StringData const& other) const
{
return bytes_as_string_view() == other.bytes_as_string_view();
}
unsigned hash() const
{
if (!m_has_hash)
compute_hash();
return m_hash;
}
bool is_fly_string() const { return m_is_fly_string; }
void set_fly_string(bool is_fly_string) const { m_is_fly_string = is_fly_string; }
private:
explicit StringData(size_t byte_count);
StringData(StringData const& superstring, size_t start, size_t byte_count);
void compute_hash() const;
u32 m_byte_count { 0 };
mutable unsigned m_hash { 0 };
mutable bool m_has_hash { false };
bool m_substring { false };
mutable bool m_is_fly_string { false };
alignas(SubstringData) u8 m_bytes_or_substring_data[0];
};
void StringData::operator delete(void* ptr)
{
free(ptr);
}
StringData::StringData(size_t byte_count)
: m_byte_count(byte_count)
{
}
StringData::StringData(StringData const& superstring, size_t start, size_t byte_count)
: m_byte_count(byte_count)
, m_substring(true)
{
auto& data = const_cast<SubstringData&>(substring_data());
data.start_offset = start;
data.superstring = &superstring;
superstring.ref();
}
StringData::~StringData()
{
if (m_is_fly_string)
FlyString::did_destroy_fly_string_data({}, bytes_as_string_view());
if (m_substring)
substring_data().superstring->unref();
}
constexpr size_t allocation_size_for_string_data(size_t length)
{
return sizeof(StringData) + (sizeof(char) * length);
}
ErrorOr<NonnullRefPtr<StringData>> StringData::create_uninitialized(size_t byte_count, u8*& buffer)
{
VERIFY(byte_count);
void* slot = malloc(allocation_size_for_string_data(byte_count));
if (!slot) {
return Error::from_errno(ENOMEM);
}
auto new_string_data = adopt_ref(*new (slot) StringData(byte_count));
buffer = const_cast<u8*>(new_string_data->bytes().data());
return new_string_data;
}
ErrorOr<NonnullRefPtr<StringData>> StringData::from_utf8(char const* utf8_data, size_t byte_count)
{
// Strings of MAX_SHORT_STRING_BYTE_COUNT bytes or less should be handled by the String short string optimization.
VERIFY(byte_count > String::MAX_SHORT_STRING_BYTE_COUNT);
VERIFY(utf8_data);
u8* buffer = nullptr;
auto new_string_data = TRY(create_uninitialized(byte_count, buffer));
memcpy(buffer, utf8_data, byte_count * sizeof(char));
return new_string_data;
}
static ErrorOr<void> read_stream_into_buffer(Stream& stream, Bytes buffer)
{
TRY(stream.read_until_filled(buffer));
if (!Utf8View { StringView { buffer } }.validate())
return Error::from_string_literal("String::from_stream: Input was not valid UTF-8");
return {};
}
ErrorOr<NonnullRefPtr<StringData>> StringData::from_stream(Stream& stream, size_t byte_count)
{
// Strings of MAX_SHORT_STRING_BYTE_COUNT bytes or less should be handled by the String short string optimization.
VERIFY(byte_count > String::MAX_SHORT_STRING_BYTE_COUNT);
u8* buffer = nullptr;
auto new_string_data = TRY(create_uninitialized(byte_count, buffer));
TRY(read_stream_into_buffer(stream, { buffer, byte_count }));
return new_string_data;
}
ErrorOr<NonnullRefPtr<StringData>> StringData::create_substring(StringData const& superstring, size_t start, size_t byte_count)
{
// Strings of MAX_SHORT_STRING_BYTE_COUNT bytes or less should be handled by the String short string optimization.
VERIFY(byte_count > String::MAX_SHORT_STRING_BYTE_COUNT);
void* slot = malloc(sizeof(StringData) + sizeof(StringData::SubstringData));
if (!slot) {
return Error::from_errno(ENOMEM);
}
return adopt_ref(*new (slot) StringData(superstring, start, byte_count));
}
void StringData::compute_hash() const
{
auto bytes = this->bytes();
if (bytes.size() == 0)
m_hash = 0;
else
m_hash = string_hash(reinterpret_cast<char const*>(bytes.data()), bytes.size());
m_has_hash = true;
}
}
String::String(NonnullRefPtr<Detail::StringData const> data)
: m_data(&data.leak_ref())
{
}
String::String(String const& other)
: m_data(other.m_data)
{
if (!is_short_string())
m_data->ref();
}
String::String(String&& other)
: m_data(exchange(other.m_data, nullptr))
{
other.m_short_string.byte_count_and_short_string_flag = SHORT_STRING_FLAG;
}
String& String::operator=(String&& other)
{
if (!is_short_string())
m_data->unref();
m_data = exchange(other.m_data, nullptr);
other.m_short_string.byte_count_and_short_string_flag = SHORT_STRING_FLAG;
return *this;
}
String& String::operator=(String const& other)
{
if (&other != this) {
m_data = other.m_data;
if (!is_short_string())
m_data->ref();
}
return *this;
}
void String::destroy_string()
{
if (!is_short_string())
m_data->unref();
}
ErrorOr<String> String::from_utf8(StringView view)
{
if (!Utf8View { view }.validate())
return Error::from_string_literal("String::from_utf8: Input was not valid UTF-8");
if (view.length() <= MAX_SHORT_STRING_BYTE_COUNT) {
ShortString short_string;
if (!view.is_empty())
memcpy(short_string.storage, view.characters_without_null_termination(), view.length());
short_string.byte_count_and_short_string_flag = (view.length() << 1) | SHORT_STRING_FLAG;
return String { short_string };
}
auto data = TRY(Detail::StringData::from_utf8(view.characters_without_null_termination(), view.length()));
return String { move(data) };
}
ErrorOr<String> String::from_stream(Stream& stream, size_t byte_count)
{
if (byte_count <= MAX_SHORT_STRING_BYTE_COUNT) {
ShortString short_string;
if (byte_count > 0)
TRY(Detail::read_stream_into_buffer(stream, { short_string.storage, byte_count }));
short_string.byte_count_and_short_string_flag = (byte_count << 1) | SHORT_STRING_FLAG;
return String { short_string };
}
auto data = TRY(Detail::StringData::from_stream(stream, byte_count));
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());
}
ReadonlyBytes String::bytes() const
{
if (is_short_string())
return m_short_string.bytes();
return m_data->bytes();
}
bool String::is_empty() const
{
return bytes().size() == 0;
}
ErrorOr<String> String::vformatted(StringView fmtstr, TypeErasedFormatParams& params)
{
StringBuilder builder;
TRY(vformat(builder, fmtstr, params));
return builder.to_string();
}
ErrorOr<Vector<String>> String::split(u32 separator, SplitBehavior split_behavior) const
{
return split_limit(separator, 0, split_behavior);
}
ErrorOr<Vector<String>> String::split_limit(u32 separator, size_t limit, SplitBehavior split_behavior) const
{
Vector<String> result;
if (is_empty())
return result;
bool keep_empty = has_flag(split_behavior, SplitBehavior::KeepEmpty);
size_t substring_start = 0;
for (auto it = code_points().begin(); it != code_points().end() && (result.size() + 1) != limit; ++it) {
u32 code_point = *it;
if (code_point == separator) {
size_t substring_length = code_points().iterator_offset(it) - substring_start;
if (substring_length != 0 || keep_empty)
TRY(result.try_append(TRY(substring_from_byte_offset_with_shared_superstring(substring_start, substring_length))));
substring_start = code_points().iterator_offset(it) + it.underlying_code_point_length_in_bytes();
}
}
size_t tail_length = code_points().byte_length() - substring_start;
if (tail_length != 0 || keep_empty)
TRY(result.try_append(TRY(substring_from_byte_offset_with_shared_superstring(substring_start, tail_length))));
return result;
}
Optional<size_t> String::find_byte_offset(u32 code_point, size_t from_byte_offset) const
{
auto code_points = this->code_points();
if (from_byte_offset >= code_points.byte_length())
return {};
for (auto it = code_points.iterator_at_byte_offset(from_byte_offset); it != code_points.end(); ++it) {
if (*it == code_point)
return code_points.byte_offset_of(it);
}
return {};
}
Optional<size_t> String::find_byte_offset(StringView substring, size_t from_byte_offset) const
{
auto view = bytes_as_string_view();
if (from_byte_offset >= view.length())
return {};
auto index = memmem_optional(
view.characters_without_null_termination() + from_byte_offset, view.length() - from_byte_offset,
substring.characters_without_null_termination(), substring.length());
if (index.has_value())
return *index + from_byte_offset;
return {};
}
bool String::operator==(String const& other) const
{
if (is_short_string())
return m_data == other.m_data;
return bytes_as_string_view() == other.bytes_as_string_view();
}
bool String::operator==(FlyString const& other) const
{
if (reinterpret_cast<uintptr_t>(m_data) == other.data({}))
return true;
return bytes_as_string_view() == other.bytes_as_string_view();
}
bool String::operator==(StringView other) const
{
return bytes_as_string_view() == other;
}
ErrorOr<String> String::substring_from_byte_offset(size_t start, size_t byte_count) const
{
if (!byte_count)
return String {};
return String::from_utf8(bytes_as_string_view().substring_view(start, byte_count));
}
ErrorOr<String> String::substring_from_byte_offset(size_t start) const
{
VERIFY(start <= bytes_as_string_view().length());
return substring_from_byte_offset(start, bytes_as_string_view().length() - start);
}
ErrorOr<String> String::substring_from_byte_offset_with_shared_superstring(size_t start, size_t byte_count) const
{
if (!byte_count)
return String {};
if (byte_count <= MAX_SHORT_STRING_BYTE_COUNT)
return String::from_utf8(bytes_as_string_view().substring_view(start, byte_count));
return String { TRY(Detail::StringData::create_substring(*m_data, start, byte_count)) };
}
ErrorOr<String> String::substring_from_byte_offset_with_shared_superstring(size_t start) const
{
VERIFY(start <= bytes_as_string_view().length());
return substring_from_byte_offset_with_shared_superstring(start, bytes_as_string_view().length() - start);
}
bool String::operator==(char const* c_string) const
{
return bytes_as_string_view() == c_string;
}
u32 String::hash() const
{
if (is_short_string()) {
auto bytes = this->bytes();
return string_hash(reinterpret_cast<char const*>(bytes.data()), bytes.size());
}
return m_data->hash();
}
Utf8View String::code_points() const
{
return Utf8View(bytes_as_string_view());
}
ErrorOr<void> Formatter<String>::format(FormatBuilder& builder, String const& utf8_string)
{
return Formatter<StringView>::format(builder, utf8_string.bytes_as_string_view());
}
ErrorOr<String> String::replace(StringView needle, StringView replacement, ReplaceMode replace_mode) const
{
return StringUtils::replace(*this, needle, replacement, replace_mode);
}
ErrorOr<String> String::reverse() const
{
// FIXME: This handles multi-byte code points, but not e.g. grapheme clusters.
// FIXME: We could avoid allocating a temporary vector if Utf8View supports reverse iteration.
auto code_point_length = code_points().length();
Vector<u32> code_points;
TRY(code_points.try_ensure_capacity(code_point_length));
for (auto code_point : this->code_points())
code_points.unchecked_append(code_point);
auto builder = TRY(StringBuilder::create(code_point_length * sizeof(u32)));
while (!code_points.is_empty())
TRY(builder.try_append_code_point(code_points.take_last()));
return builder.to_string();
}
ErrorOr<String> String::trim(Utf8View const& code_points_to_trim, TrimMode mode) const
{
auto trimmed = code_points().trim(code_points_to_trim, mode);
return String::from_utf8(trimmed.as_string());
}
ErrorOr<String> String::trim(StringView code_points_to_trim, TrimMode mode) const
{
return trim(Utf8View { code_points_to_trim }, mode);
}
bool String::contains(StringView needle, CaseSensitivity case_sensitivity) const
{
return StringUtils::contains(bytes_as_string_view(), needle, case_sensitivity);
}
bool String::contains(u32 needle, CaseSensitivity case_sensitivity) const
{
auto needle_as_string = String::from_code_point(needle);
return contains(needle_as_string.bytes_as_string_view(), case_sensitivity);
}
bool String::starts_with(u32 code_point) const
{
if (is_empty())
return false;
return *code_points().begin() == code_point;
}
bool String::starts_with_bytes(StringView bytes) const
{
return bytes_as_string_view().starts_with(bytes);
}
bool String::ends_with(u32 code_point) const
{
if (is_empty())
return false;
u32 last_code_point = 0;
for (auto it = code_points().begin(); it != code_points().end(); ++it)
last_code_point = *it;
return last_code_point == code_point;
}
bool String::ends_with_bytes(StringView bytes) const
{
return bytes_as_string_view().ends_with(bytes);
}
bool String::is_short_string() const
{
return has_short_string_bit(reinterpret_cast<uintptr_t>(m_data));
}
ReadonlyBytes String::ShortString::bytes() const
{
return { storage, byte_count() };
}
size_t String::ShortString::byte_count() const
{
return byte_count_and_short_string_flag >> 1;
}
unsigned Traits<String>::hash(String const& string)
{
return string.hash();
}
String String::fly_string_data_to_string(Badge<FlyString>, uintptr_t const& data)
{
if (has_short_string_bit(data))
return String { *reinterpret_cast<ShortString const*>(&data) };
auto const* string_data = reinterpret_cast<Detail::StringData const*>(data);
return String { NonnullRefPtr<Detail::StringData const>(*string_data) };
}
StringView String::fly_string_data_to_string_view(Badge<FlyString>, uintptr_t const& data)
{
if (has_short_string_bit(data)) {
auto const* short_string = reinterpret_cast<ShortString const*>(&data);
return short_string->bytes();
}
auto const* string_data = reinterpret_cast<Detail::StringData const*>(data);
return string_data->bytes_as_string_view();
}
u32 String::fly_string_data_to_hash(Badge<FlyString>, uintptr_t const& data)
{
if (has_short_string_bit(data)) {
auto const* short_string = reinterpret_cast<ShortString const*>(&data);
auto bytes = short_string->bytes();
return string_hash(reinterpret_cast<char const*>(bytes.data()), bytes.size());
}
auto const* string_data = reinterpret_cast<Detail::StringData const*>(data);
return string_data->hash();
}
uintptr_t String::to_fly_string_data(Badge<FlyString>) const
{
return reinterpret_cast<uintptr_t>(m_data);
}
void String::ref_fly_string_data(Badge<FlyString>, uintptr_t data)
{
if (has_short_string_bit(data))
return;
auto const* string_data = reinterpret_cast<Detail::StringData const*>(data);
string_data->ref();
}
void String::unref_fly_string_data(Badge<FlyString>, uintptr_t data)
{
if (has_short_string_bit(data))
return;
auto const* string_data = reinterpret_cast<Detail::StringData const*>(data);
string_data->unref();
}
void String::did_create_fly_string(Badge<FlyString>) const
{
VERIFY(!is_short_string());
m_data->set_fly_string(true);
}
DeprecatedString String::to_deprecated_string() const
{
return DeprecatedString(bytes_as_string_view());
}
ErrorOr<String> String::from_deprecated_string(DeprecatedString const& deprecated_string)
{
return String::from_utf8(deprecated_string.view());
}
}