ladybird/AK/StringImpl.cpp

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/*
* 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/FlyString.h>
#include <AK/HashTable.h>
#include <AK/Memory.h>
#include <AK/StdLibExtras.h>
#include <AK/StringImpl.h>
#include <AK/kmalloc.h>
//#define DEBUG_STRINGIMPL
#ifdef DEBUG_STRINGIMPL
unsigned g_stringimpl_count;
static HashTable<StringImpl*>* g_all_live_stringimpls;
void dump_all_stringimpls()
{
unsigned i = 0;
for (auto& it : *g_all_live_stringimpls) {
dbgprsize_tf("%u: \"%s\"\n", i, (*it).characters());
++i;
}
}
#endif
namespace AK {
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static StringImpl* s_the_empty_stringimpl = nullptr;
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StringImpl& StringImpl::the_empty_stringimpl()
{
if (!s_the_empty_stringimpl) {
void* slot = kmalloc(sizeof(StringImpl) + sizeof(char));
s_the_empty_stringimpl = new (slot) StringImpl(ConstructTheEmptyStringImpl);
}
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return *s_the_empty_stringimpl;
}
StringImpl::StringImpl(ConstructWithInlineBufferTag, size_t length)
: m_length(length)
{
#ifdef DEBUG_STRINGIMPL
if (!g_all_live_stringimpls)
g_all_live_stringimpls = new HashTable<StringImpl*>;
++g_stringimpl_count;
g_all_live_stringimpls->set(this);
#endif
}
StringImpl::~StringImpl()
{
if (m_fly)
FlyString::did_destroy_impl({}, *this);
#ifdef DEBUG_STRINGIMPL
--g_stringimpl_count;
g_all_live_stringimpls->remove(this);
#endif
}
static inline size_t allocation_size_for_stringimpl(size_t length)
{
return sizeof(StringImpl) + (sizeof(char) * length) + sizeof(char);
}
NonnullRefPtr<StringImpl> StringImpl::create_uninitialized(size_t length, char*& buffer)
{
ASSERT(length);
void* slot = kmalloc(allocation_size_for_stringimpl(length));
ASSERT(slot);
auto new_stringimpl = adopt(*new (slot) StringImpl(ConstructWithInlineBuffer, length));
buffer = const_cast<char*>(new_stringimpl->characters());
buffer[length] = '\0';
return new_stringimpl;
}
RefPtr<StringImpl> StringImpl::create(const char* cstring, size_t length, ShouldChomp should_chomp)
{
if (!cstring)
return nullptr;
if (!length || !*cstring)
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return the_empty_stringimpl();
if (should_chomp) {
while (length) {
char last_ch = cstring[length - 1];
if (!last_ch || last_ch == '\n' || last_ch == '\r')
--length;
else
break;
}
}
if (!length)
return the_empty_stringimpl();
char* buffer;
auto new_stringimpl = create_uninitialized(length, buffer);
memcpy(buffer, cstring, length * sizeof(char));
return new_stringimpl;
}
RefPtr<StringImpl> StringImpl::create(const char* cstring, ShouldChomp shouldChomp)
{
if (!cstring)
return nullptr;
return create(cstring, strlen(cstring), shouldChomp);
}
static inline bool is_ascii_lowercase(char c)
{
return c >= 'a' && c <= 'z';
}
static inline bool is_ascii_uppercase(char c)
{
return c >= 'A' && c <= 'Z';
}
static inline char to_ascii_lowercase(char c)
{
if (is_ascii_uppercase(c))
return c | 0x20;
return c;
}
static inline char to_ascii_uppercase(char c)
{
if (is_ascii_lowercase(c))
return c & ~0x20;
return c;
}
NonnullRefPtr<StringImpl> StringImpl::to_lowercase() const
{
for (size_t i = 0; i < m_length; ++i) {
if (!is_ascii_lowercase(characters()[i]))
goto slow_path;
}
return const_cast<StringImpl&>(*this);
slow_path:
char* buffer;
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auto lowercased = create_uninitialized(m_length, buffer);
for (size_t i = 0; i < m_length; ++i)
buffer[i] = to_ascii_lowercase(characters()[i]);
return lowercased;
}
NonnullRefPtr<StringImpl> StringImpl::to_uppercase() const
{
for (size_t i = 0; i < m_length; ++i) {
if (!is_ascii_uppercase(characters()[i]))
goto slow_path;
}
return const_cast<StringImpl&>(*this);
slow_path:
char* buffer;
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auto uppercased = create_uninitialized(m_length, buffer);
for (size_t i = 0; i < m_length; ++i)
buffer[i] = to_ascii_uppercase(characters()[i]);
return uppercased;
}
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void StringImpl::compute_hash() const
{
if (!length())
m_hash = 0;
else
m_hash = string_hash(characters(), m_length);
m_has_hash = true;
}
}