ladybird/Userland/Libraries/LibJS/Runtime/PrimitiveString.cpp
Timothy Flynn 4c2cc419f9 LibJS: Decode UTF-16 surrogate pairs during string literal construction
Rather than deferring this decoding to PrimitiveString, we can decode
surrogate pairs when parsing the string. This prevents a string copy
when constructing the PrimitiveString.
2021-08-04 11:18:24 +02:00

74 lines
1.8 KiB
C++

/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/CharacterTypes.h>
#include <AK/Utf16View.h>
#include <LibJS/Runtime/PrimitiveString.h>
#include <LibJS/Runtime/VM.h>
namespace JS {
PrimitiveString::PrimitiveString(String string)
: m_string(move(string))
{
}
PrimitiveString::~PrimitiveString()
{
}
Vector<u16> const& PrimitiveString::utf16_string() const
{
if (m_utf16_string.is_empty() && !m_string.is_empty())
m_utf16_string = AK::utf8_to_utf16(m_string);
return m_utf16_string;
}
Utf16View PrimitiveString::utf16_string_view() const
{
return Utf16View { utf16_string() };
}
PrimitiveString* js_string(Heap& heap, Utf16View const& string)
{
if (string.is_empty())
return &heap.vm().empty_string();
if (string.length_in_code_units() == 1) {
u16 code_unit = string.code_unit_at(0);
if (is_ascii(code_unit))
return &heap.vm().single_ascii_character_string(static_cast<u8>(code_unit));
}
auto utf8_string = string.to_utf8(Utf16View::AllowInvalidCodeUnits::Yes);
return heap.allocate_without_global_object<PrimitiveString>(move(utf8_string));
}
PrimitiveString* js_string(VM& vm, Utf16View const& string)
{
return js_string(vm.heap(), string);
}
PrimitiveString* js_string(Heap& heap, String string)
{
if (string.is_empty())
return &heap.vm().empty_string();
if (string.length() == 1) {
auto ch = static_cast<u8>(string.characters()[0]);
if (is_ascii(ch))
return &heap.vm().single_ascii_character_string(ch);
}
return heap.allocate_without_global_object<PrimitiveString>(move(string));
}
PrimitiveString* js_string(VM& vm, String string)
{
return js_string(vm.heap(), move(string));
}
}