ladybird/AK/StringImpl.cpp
Andreas Kling f93b3b7806 AK: Improve StringImpl chomping a bit.
Chomp off any number of trailing [\0\n\r] characters and trim the allocation
to fit instead of keeping the original size.
2019-04-07 20:21:11 +02:00

172 lines
3.9 KiB
C++

#include "StringImpl.h"
#include "StdLibExtras.h"
#include "kmalloc.h"
#include "HashTable.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) {
dbgprintf("%u: \"%s\"\n", i, (*it).characters());
++i;
}
}
#endif
namespace AK {
static StringImpl* s_the_empty_stringimpl = nullptr;
StringImpl& StringImpl::the_empty_stringimpl()
{
if (!s_the_empty_stringimpl)
s_the_empty_stringimpl = new StringImpl(ConstructTheEmptyStringImpl);;
return *s_the_empty_stringimpl;
}
StringImpl::StringImpl(ConstructWithInlineBufferTag, ssize_t length)
: m_length(length)
, m_characters(m_inline_buffer)
{
#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()
{
#ifdef DEBUG_STRINGIMPL
--g_stringimpl_count;
g_all_live_stringimpls->remove(this);
#endif
}
static inline ssize_t allocation_size_for_stringimpl(ssize_t length)
{
return sizeof(StringImpl) + (sizeof(char) * length) + sizeof(char);
}
Retained<StringImpl> StringImpl::create_uninitialized(ssize_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->m_characters);
buffer[length] = '\0';
return new_stringimpl;
}
RetainPtr<StringImpl> StringImpl::create(const char* cstring, ssize_t length, ShouldChomp should_chomp)
{
if (!cstring)
return nullptr;
if (!*cstring)
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;
}
RetainPtr<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;
}
Retained<StringImpl> StringImpl::to_lowercase() const
{
for (ssize_t i = 0; i < m_length; ++i) {
if (!is_ascii_lowercase(m_characters[i]))
goto slow_path;
}
return const_cast<StringImpl&>(*this);
slow_path:
char* buffer;
auto lowercased = create_uninitialized(m_length, buffer);
for (ssize_t i = 0; i < m_length; ++i)
buffer[i] = to_ascii_lowercase(m_characters[i]);
return lowercased;
}
Retained<StringImpl> StringImpl::to_uppercase() const
{
for (ssize_t i = 0; i < m_length; ++i) {
if (!is_ascii_uppercase(m_characters[i]))
goto slow_path;
}
return const_cast<StringImpl&>(*this);
slow_path:
char* buffer;
auto uppercased = create_uninitialized(m_length, buffer);
for (ssize_t i = 0; i < m_length; ++i)
buffer[i] = to_ascii_uppercase(m_characters[i]);
return uppercased;
}
void StringImpl::compute_hash() const
{
if (!length())
m_hash = 0;
else
m_hash = string_hash(m_characters, m_length);
m_hasHash = true;
}
}