ladybird/AK/StringImpl.cpp

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#include "StringImpl.h"
#include "StdLibExtras.h"
#include "kmalloc.h"
#include "HashTable.h"
#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 {
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static StringImpl* s_the_empty_stringimpl = nullptr;
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void StringImpl::initialize_globals()
{
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s_the_empty_stringimpl = nullptr;
#ifdef DEBUG_STRINGIMPL
g_stringimpl_count = 0;
g_all_live_stringimpls = new HashTable<StringImpl*>;
#endif
}
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StringImpl& StringImpl::the_empty_stringimpl()
{
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if (!s_the_empty_stringimpl)
s_the_empty_stringimpl = new StringImpl(ConstructTheEmptyStringImpl);;
return *s_the_empty_stringimpl;
}
StringImpl::StringImpl(ConstructWithInlineBufferTag, size_t length)
: m_length(length)
, m_characters(m_inline_buffer)
{
#ifdef DEBUG_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 size_t allocation_size_for_stringimpl(size_t length)
{
return sizeof(StringImpl) + (sizeof(char) * length) + sizeof(char);
}
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RetainPtr<StringImpl> StringImpl::create_uninitialized(size_t length, char*& buffer)
{
ASSERT(length);
void* slot = kmalloc(allocation_size_for_stringimpl(length));
if (!slot)
return nullptr;
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, size_t length, ShouldChomp shouldChomp)
{
if (!cstring)
return nullptr;
if (!*cstring)
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return the_empty_stringimpl();
char* buffer;
auto new_stringimpl = create_uninitialized(length, buffer);
if (!new_stringimpl)
return nullptr;
memcpy(buffer, cstring, length * sizeof(char));
if (shouldChomp && buffer[length - 1] == '\n') {
buffer[length - 1] = '\0';
--new_stringimpl->m_length;
}
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;
}
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RetainPtr<StringImpl> StringImpl::to_lowercase() const
{
if (!m_length)
return const_cast<StringImpl*>(this);
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for (size_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;
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auto lowercased = create_uninitialized(m_length, buffer);
if (!lowercased)
return nullptr;
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for (size_t i = 0; i < m_length; ++i)
buffer[i] = to_ascii_lowercase(m_characters[i]);
return lowercased;
}
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RetainPtr<StringImpl> StringImpl::to_uppercase() const
{
if (!m_length)
return const_cast<StringImpl*>(this);
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for (size_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;
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auto uppercased = create_uninitialized(m_length, buffer);
if (!uppercased)
return nullptr;
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for (size_t i = 0; i < m_length; ++i)
buffer[i] = to_ascii_uppercase(m_characters[i]);
return uppercased;
}
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void StringImpl::compute_hash() const
{
if (!length()) {
m_hash = 0;
} else {
unsigned hash = 0;
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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;
}
}