ladybird/AK/StringImpl.cpp
2018-10-22 22:46:02 +02:00

153 lines
3.3 KiB
C++

#include "StringImpl.h"
#include "StdLib.h"
#include "kmalloc.h"
namespace AK {
static StringImpl* s_theEmptyStringImpl = nullptr;
void StringImpl::initializeGlobals()
{
s_theEmptyStringImpl = nullptr;
}
StringImpl& StringImpl::theEmptyStringImpl()
{
if (!s_theEmptyStringImpl)
s_theEmptyStringImpl = new StringImpl(ConstructTheEmptyStringImpl);;
return *s_theEmptyStringImpl;
}
StringImpl::~StringImpl()
{
}
static inline size_t allocationSizeForStringImpl(size_t length)
{
return sizeof(StringImpl) + (sizeof(char) * length) + sizeof(char);
}
RetainPtr<StringImpl> StringImpl::createUninitialized(size_t length, char*& buffer)
{
if (!length)
return theEmptyStringImpl();
void* slot = kmalloc(allocationSizeForStringImpl(length));
if (!slot)
return nullptr;
auto newStringImpl = adopt(*new (slot) StringImpl(ConstructWithInlineBuffer, length));
buffer = const_cast<char*>(newStringImpl->m_characters);
buffer[length] = '\0';
return newStringImpl;
}
RetainPtr<StringImpl> StringImpl::create(const char* cstring, size_t length)
{
if (!cstring)
return nullptr;
if (!*cstring)
return theEmptyStringImpl();
char* buffer;
auto newStringImpl = createUninitialized(length, buffer);
memcpy(buffer, cstring, length * sizeof(char));
return newStringImpl;
}
RetainPtr<StringImpl> StringImpl::create(const char* cstring)
{
if (!cstring)
return nullptr;
return create(cstring, strlen(cstring));
}
static inline bool isASCIILowercase(char c)
{
return c >= 'a' && c <= 'z';
}
static inline bool isASCIIUppercase(char c)
{
return c >= 'A' && c <= 'Z';
}
static inline char toASCIILowercase(char c)
{
if (isASCIIUppercase(c))
return c | 0x20;
return c;
}
static inline char toASCIIUppercase(char c)
{
if (isASCIILowercase(c))
return c & ~0x20;
return c;
}
RetainPtr<StringImpl> StringImpl::toLowercase() const
{
if (!m_length)
return const_cast<StringImpl*>(this);
for (size_t i = 0; i < m_length; ++i) {
if (!isASCIILowercase(m_characters[i]))
goto slowPath;
}
return const_cast<StringImpl*>(this);
slowPath:
char* buffer;
auto lowercased = createUninitialized(m_length, buffer);
for (size_t i = 0; i < m_length; ++i)
buffer[i] = toASCIILowercase(m_characters[i]);
return lowercased;
}
RetainPtr<StringImpl> StringImpl::toUppercase() const
{
if (!m_length)
return const_cast<StringImpl*>(this);
for (size_t i = 0; i < m_length; ++i) {
if (!isASCIIUppercase(m_characters[i]))
goto slowPath;
}
return const_cast<StringImpl*>(this);
slowPath:
char* buffer;
auto uppercased = createUninitialized(m_length, buffer);
for (size_t i = 0; i < m_length; ++i)
buffer[i] = toASCIIUppercase(m_characters[i]);
return uppercased;
}
void StringImpl::computeHash() const
{
if (!length()) {
m_hash = 0;
} else {
unsigned hash = 0;
for (size_t i = 0; i < m_length; ++i) {
hash += m_characters[i];
hash += (hash << 10);
hash ^= (hash >> 6);
}
hash += hash << 3;
hash ^= hash >> 11;
hash += hash << 15;
m_hash = hash;
}
m_hasHash = true;
}
}