ladybird/AK/StringBuilder.cpp
Andreas Kling 54ade31d84 AK: Add some inline capacity to StringBuilder
This patch adds a 128-byte inline buffer that we use before switching
to using a dynamically growing ByteBuffer.

This allows us to avoid heap allocations in many cases, and totally
incidentally also speeds up @nico's favorite test, "disasm /bin/id"
more than 2x. :^)
2020-11-24 22:06:51 +01:00

190 lines
5.3 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <AK/ByteBuffer.h>
#include <AK/Checked.h>
#include <AK/Memory.h>
#include <AK/PrintfImplementation.h>
#include <AK/StdLibExtras.h>
#include <AK/String.h>
#include <AK/StringBuilder.h>
#include <AK/StringView.h>
#include <AK/Utf32View.h>
namespace AK {
inline void StringBuilder::will_append(size_t size)
{
Checked<size_t> needed_capacity = m_length;
needed_capacity += size;
ASSERT(!needed_capacity.has_overflow());
if (needed_capacity < inline_capacity)
return;
Checked<size_t> expanded_capacity = needed_capacity;
expanded_capacity *= 2;
ASSERT(!expanded_capacity.has_overflow());
if (m_buffer.is_null()) {
m_buffer.grow(expanded_capacity.value());
memcpy(m_buffer.data(), m_inline_buffer, m_length);
} else if (needed_capacity.value() > m_buffer.size()) {
m_buffer.grow(expanded_capacity.value());
}
}
StringBuilder::StringBuilder(size_t initial_capacity)
{
if (initial_capacity > inline_capacity)
m_buffer.grow(initial_capacity);
}
void StringBuilder::append(const StringView& str)
{
if (str.is_empty())
return;
will_append(str.length());
memcpy(data() + m_length, str.characters_without_null_termination(), str.length());
m_length += str.length();
}
void StringBuilder::append(const char* characters, size_t length)
{
append(StringView { characters, length });
}
void StringBuilder::append(char ch)
{
will_append(1);
data()[m_length] = ch;
m_length += 1;
}
void StringBuilder::appendvf(const char* fmt, va_list ap)
{
printf_internal([this](char*&, char ch) {
append(ch);
},
nullptr, fmt, ap);
}
void StringBuilder::appendf(const char* fmt, ...)
{
va_list ap;
va_start(ap, fmt);
will_append(strlen(fmt));
appendvf(fmt, ap);
va_end(ap);
}
ByteBuffer StringBuilder::to_byte_buffer() const
{
return ByteBuffer::copy(data(), length());
}
String StringBuilder::to_string() const
{
if (is_empty())
return String::empty();
return String((const char*)data(), length());
}
String StringBuilder::build() const
{
return to_string();
}
StringView StringBuilder::string_view() const
{
return StringView { data(), m_length };
}
void StringBuilder::clear()
{
m_buffer.clear();
m_inline_buffer[0] = '\0';
m_length = 0;
}
void StringBuilder::append_code_point(u32 code_point)
{
if (code_point <= 0x7f) {
append((char)code_point);
} else if (code_point <= 0x07ff) {
append((char)(((code_point >> 6) & 0x1f) | 0xc0));
append((char)(((code_point >> 0) & 0x3f) | 0x80));
} else if (code_point <= 0xffff) {
append((char)(((code_point >> 12) & 0x0f) | 0xe0));
append((char)(((code_point >> 6) & 0x3f) | 0x80));
append((char)(((code_point >> 0) & 0x3f) | 0x80));
} else if (code_point <= 0x10ffff) {
append((char)(((code_point >> 18) & 0x07) | 0xf0));
append((char)(((code_point >> 12) & 0x3f) | 0x80));
append((char)(((code_point >> 6) & 0x3f) | 0x80));
append((char)(((code_point >> 0) & 0x3f) | 0x80));
} else {
append(0xef);
append(0xbf);
append(0xbd);
}
}
void StringBuilder::append(const Utf32View& utf32_view)
{
for (size_t i = 0; i < utf32_view.length(); ++i) {
auto code_point = utf32_view.code_points()[i];
append_code_point(code_point);
}
}
void StringBuilder::append_escaped_for_json(const StringView& string)
{
for (auto ch : string) {
switch (ch) {
case '\e':
append("\\u001B");
break;
case '\b':
append("\\b");
break;
case '\n':
append("\\n");
break;
case '\t':
append("\\t");
break;
case '\"':
append("\\\"");
break;
case '\\':
append("\\\\");
break;
default:
append(ch);
}
}
}
}