An embedded string object of fixed max-length, which uses no external memory. More...

Detailed Description

template<uint MAXLEN, typename CHAR = char>
class foedus::assorted::FixedString< MAXLEN, CHAR >

An embedded string object of fixed max-length, which uses no external memory.

This header-only object behaves like std::string in many ways. The key difference is that this object is essentially a fixed array while std::string allocates memory in heap (with some exception for optimized stack-allocation, but that's not the point).

This implies a few crucial characteristics.

We can copy/overwrite a piece of memory containing this object without taking care of heap-allocated memory (which makes the handling of shared memory much easier).
We have limit on the length of the string, determined at compile time (a template param).
We always consume that much memory regardless the actual content.

Usecases

As mentioned above, this object is used where we can't use std::string that points to somewhere else. For example, use it as follows.

struct MyPage {
  FixedString<12>  str1_;  // +4+12
  FixedString<8>   str2_;  // +4+8+4 (Anyway 8 byte aligned..)
  char             other_data_[4096-32];
};
// This page can be simply memcpy-ed unlike a struct that contains std::string.

Limitations

No char traits for exotic comparison rules. Not more than 2^32-1 chars. Length 2^32-1 is reserved for npos.

Definition at line 65 of file fixed_string.hpp.

#include <fixed_string.hpp>

Public Member Functions
	FixedString () noexcept
	Constructs an empty string. More...

template<uint MAXLEN2>
	FixedString (const FixedString< MAXLEN2, CHAR > &other) noexcept
	Copy constructor for all FixedString objects. More...

	FixedString (const CHAR *str, uint32_t len) noexcept
	Copy constructor for char* and len. More...

	FixedString (const CHAR *str) noexcept
	Copy constructor for null-terminated char*. More...

template<uint MAXLEN2>
FixedString &	operator= (const FixedString< MAXLEN2, CHAR > &other) noexcept
	Assign operator for all FixedString objects. More...

template<uint MAXLEN2>
bool	operator== (const FixedString< MAXLEN2, CHAR > &other) const noexcept

template<uint MAXLEN2>
bool	operator!= (const FixedString< MAXLEN2, CHAR > &other) const noexcept

template<uint MAXLEN2>
bool	operator< (const FixedString< MAXLEN2, CHAR > &other) const noexcept

template<uint MAXLEN2>
void	assign (const FixedString< MAXLEN2, CHAR > &other) noexcept
	Assign operator for all FixedString objects. More...

void	assign (const std::basic_string< CHAR > &str) noexcept
	Assign operator for std::string. More...

void	assign (const CHAR *str, uint32_t len) noexcept
	Assign operator for char* and length. More...

template<uint MAXLEN2>
void	append (const FixedString< MAXLEN2, CHAR > &other) noexcept
	Append operator for all FixedString objects. More...

void	append (const std::basic_string< CHAR > &str) noexcept
	Append operator for std::string. More...

void	append (const CHAR *str, uint32_t len) noexcept
	Append operator for char* and length. More...

uint32_t	length () const noexcept
	Returns the length of this string. More...

uint32_t	size () const noexcept
	Returns the length of this string. More...

uint32_t	capacity () const noexcept
	Return size of allocated storage. More...

uint32_t	max_size () const noexcept
	Return maximum size of string. More...

void	clear () noexcept
	Clear string. More...

bool	empty () const noexcept
	Test if string is empty. More...

void	zero_fill_remaining () const noexcept
	Sets zeros to unused data_ region. More...

const CHAR *	data () const noexcept
	Get string data. More...

std::basic_string< CHAR >	str () const
	Convert to a std::string object. More...

const CHAR *	c_str () const
	Convert to a C string. More...

Static Public Member Functions
static uint32_t	strlen (const char *str) noexcept

static uint32_t	strlen (const wchar_t *str) noexcept

Static Public Attributes
static const uint32_t	npos = -1
	npos is a static member constant value with the greatest possible value for uint32_t. More...

Friends
std::ostream &	operator<< (std::ostream &o, const FixedString &v)

Constructor & Destructor Documentation

template<uint MAXLEN, typename CHAR = char>

foedus::assorted::FixedString< MAXLEN, CHAR >::FixedString ( )

inlinenoexcept

Constructs an empty string.

Definition at line 68 of file fixed_string.hpp.

68 : length_(0) {}

template<uint MAXLEN, typename CHAR = char>

template<uint MAXLEN2>

foedus::assorted::FixedString< MAXLEN, CHAR >::FixedString ( const FixedString< MAXLEN2, CHAR > & other )

inlineexplicitnoexcept

Copy constructor for all FixedString objects.

Note that too-long strings are truncated.

Definition at line 72 of file fixed_string.hpp.

72 { assign(other); }

foedus::assorted::FixedString::assign

void assign(const FixedString< MAXLEN2, CHAR > &other) noexcept

Assign operator for all FixedString objects.

Definition: fixed_string.hpp:119

template<uint MAXLEN, typename CHAR = char>

foedus::assorted::FixedString< MAXLEN, CHAR >::FixedString	(	const CHAR *	str,
		uint32_t	len
	)

inlinenoexcept

Copy constructor for char* and len.

Note that too-long strings are truncated.

Definition at line 75 of file fixed_string.hpp.

75 { assign(str, len); }

foedus::assorted::FixedString::assign

void assign(const FixedString< MAXLEN2, CHAR > &other) noexcept

Assign operator for all FixedString objects.

Definition: fixed_string.hpp:119

foedus::assorted::FixedString::str

std::basic_string< CHAR > str() const

Convert to a std::string object.

Definition: fixed_string.hpp:185

template<uint MAXLEN, typename CHAR = char>

foedus::assorted::FixedString< MAXLEN, CHAR >::FixedString ( const CHAR * str )

inlinenoexcept

Copy constructor for null-terminated char*.

Note that too-long strings are truncated.

Definition at line 78 of file fixed_string.hpp.

                                               {  // NOLINT(runtime/explicit) follows std::string
     assign(str, strlen(str));
   }

Member Function Documentation

template<uint MAXLEN, typename CHAR = char>

template<uint MAXLEN2>

void foedus::assorted::FixedString< MAXLEN, CHAR >::append ( const FixedString< MAXLEN2, CHAR > & other )

inlinenoexcept

Append operator for all FixedString objects.

Note that too-long strings are truncated.

Definition at line 138 of file fixed_string.hpp.

                                                                            {
     ASSERT_ND(other.length() <= MAXLEN2);
     uint32_t len = length_ + other.length() > MAXLEN ? MAXLEN - length_ : other.length();
     std::memcpy(data_ + length_, other.data(), len * sizeof(CHAR));
     length_ += len;
   }

template<uint MAXLEN, typename CHAR = char>

void foedus::assorted::FixedString< MAXLEN, CHAR >::append ( const std::basic_string< CHAR > & str )

inlinenoexcept

Append operator for std::string.

Note that too-long strings are truncated.

Definition at line 146 of file fixed_string.hpp.

                                                                     {
     uint32_t len = length_ + str.size() > MAXLEN ? MAXLEN - length_ : str.size();
     std::memcpy(data_ + length_, str.data(), len * sizeof(CHAR));
     length_ += len;
   }

template<uint MAXLEN, typename CHAR = char>

void foedus::assorted::FixedString< MAXLEN, CHAR >::append	(	const CHAR *	str,
		uint32_t	len
	)

inlinenoexcept

Append operator for char* and length.

Note that too-long strings are truncated.

Definition at line 153 of file fixed_string.hpp.

                                                                  {
     len = length_ + len > MAXLEN ? MAXLEN - length_ : len;
     std::memcpy(data_ + length_, str, len * sizeof(CHAR));
     length_ += len;
   }

template<uint MAXLEN, typename CHAR = char>

template<uint MAXLEN2>

void foedus::assorted::FixedString< MAXLEN, CHAR >::assign ( const FixedString< MAXLEN2, CHAR > & other )

inlinenoexcept

Assign operator for all FixedString objects.

Note that too-long strings are truncated.

Definition at line 119 of file fixed_string.hpp.

Referenced by foedus::assorted::FixedString< 60 >::FixedString(), foedus::externalize::Externalizable::get_element(), foedus::FixedErrorStack::operator=(), foedus::assorted::FixedString< 60 >::operator=(), and foedus::memory::PagePoolPimpl::set_debug_pool_name().

                                                                            {
     ASSERT_ND(other.length() <= MAXLEN2);
     length_ = other.length() > MAXLEN ? MAXLEN : other.length();
     std::memcpy(data_, other.data(), length_ * sizeof(CHAR));
   }

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template<uint MAXLEN, typename CHAR = char>

void foedus::assorted::FixedString< MAXLEN, CHAR >::assign ( const std::basic_string< CHAR > & str )

inlinenoexcept

Assign operator for std::string.

Note that too-long strings are truncated.

Definition at line 125 of file fixed_string.hpp.

                                                                     {
     length_ = str.size() > MAXLEN ? MAXLEN : str.size();
     std::memcpy(data_, str.data(), length_ * sizeof(CHAR));
   }

template<uint MAXLEN, typename CHAR = char>

void foedus::assorted::FixedString< MAXLEN, CHAR >::assign	(	const CHAR *	str,
		uint32_t	len
	)

inlinenoexcept

Assign operator for char* and length.

Note that too-long strings are truncated.

Definition at line 131 of file fixed_string.hpp.

                                                                  {
     length_ = len > MAXLEN ? MAXLEN : len;
     std::memcpy(data_, str, length_ * sizeof(CHAR));
   }

template<uint MAXLEN, typename CHAR = char>

const CHAR* foedus::assorted::FixedString< MAXLEN, CHAR >::c_str ( ) const

inline

Convert to a C string.

Definition at line 189 of file fixed_string.hpp.

Referenced by foedus::proc::ProcManagerPimpl::get_proc().

189 { return str().c_str(); }

foedus::assorted::FixedString::str

std::basic_string< CHAR > str() const

Convert to a std::string object.

Definition: fixed_string.hpp:185

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template<uint MAXLEN, typename CHAR = char>

uint32_t foedus::assorted::FixedString< MAXLEN, CHAR >::capacity ( ) const

inlinenoexcept

Return size of allocated storage.

Actually a constexpr.

Definition at line 166 of file fixed_string.hpp.

166 { return MAXLEN; }

template<uint MAXLEN, typename CHAR = char>

void foedus::assorted::FixedString< MAXLEN, CHAR >::clear ( )

inlinenoexcept

Clear string.

Definition at line 170 of file fixed_string.hpp.

Referenced by foedus::memory::PagePoolPimpl::attach(), foedus::FixedErrorStack::from_error_stack(), foedus::thread::ThreadControlBlock::initialize(), foedus::externalize::TinyxmlGetter< assorted::FixedString< MAXLEN, CHAR > >::operator()(), and foedus::FixedErrorStack::operator=().

170 { length_ = 0; }

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template<uint MAXLEN, typename CHAR = char>

const CHAR* foedus::assorted::FixedString< MAXLEN, CHAR >::data ( ) const

inlinenoexcept

Get string data.

Definition at line 183 of file fixed_string.hpp.

183 { return data_; }

template<uint MAXLEN, typename CHAR = char>

bool foedus::assorted::FixedString< MAXLEN, CHAR >::empty ( ) const

inlinenoexcept

Test if string is empty.

Definition at line 172 of file fixed_string.hpp.

Referenced by foedus::soc::SocOptions::convert_spawn_executable_pattern(), foedus::soc::SocOptions::convert_spawn_ld_library_path_pattern(), foedus::storage::StorageManagerPimpl::create_storage(), foedus::storage::StorageManagerPimpl::create_storage_apply(), foedus::memory::PagePoolPimpl::get_debug_pool_name(), and foedus::storage::StorageManagerPimpl::initialize_read_latest_snapshot().

172 { return length_ == 0; }

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template<uint MAXLEN, typename CHAR = char>

uint32_t foedus::assorted::FixedString< MAXLEN, CHAR >::length ( ) const

inlinenoexcept

Returns the length of this string.

Definition at line 162 of file fixed_string.hpp.

162 { return length_; }

template<uint MAXLEN, typename CHAR = char>

uint32_t foedus::assorted::FixedString< MAXLEN, CHAR >::max_size ( ) const

inlinenoexcept

Return maximum size of string.

Actually a constexpr.

Definition at line 168 of file fixed_string.hpp.

168 { return MAXLEN; }

template<uint MAXLEN, typename CHAR = char>

template<uint MAXLEN2>

bool foedus::assorted::FixedString< MAXLEN, CHAR >::operator!= ( const FixedString< MAXLEN2, CHAR > & other ) const

inlinenoexcept

Definition at line 101 of file fixed_string.hpp.

                                                                                 {
     return !operator==(other);
   }

template<uint MAXLEN, typename CHAR = char>

template<uint MAXLEN2>

bool foedus::assorted::FixedString< MAXLEN, CHAR >::operator< ( const FixedString< MAXLEN2, CHAR > & other ) const

inlinenoexcept

Definition at line 105 of file fixed_string.hpp.

                                                                                {
     uint32_t min_len = std::min<uint32_t>(length_, other.length());
     if (min_len == 0) {
       return length_ < other.length();
     }
     int result = std::memcmp(data_, other.data(), min_len * sizeof(CHAR));
     if (result != 0) {
       return result < 0;
     }
     return length_ < other.length();
   }

template<uint MAXLEN, typename CHAR = char>

template<uint MAXLEN2>

FixedString& foedus::assorted::FixedString< MAXLEN, CHAR >::operator= ( const FixedString< MAXLEN2, CHAR > & other )

inlinenoexcept

Assign operator for all FixedString objects.

Note that too-long strings are truncated.

Definition at line 87 of file fixed_string.hpp.

                                                                                  {
     assign(other);
     return *this;
   }

template<uint MAXLEN, typename CHAR = char>

template<uint MAXLEN2>

bool foedus::assorted::FixedString< MAXLEN, CHAR >::operator== ( const FixedString< MAXLEN2, CHAR > & other ) const

inlinenoexcept

Definition at line 93 of file fixed_string.hpp.

Referenced by foedus::assorted::FixedString< 60 >::operator!=().

                                                                                 {
     if (length_ == 0) {
       return other.length() == 0;
     }
     return length_ == other.length() &&
       std::memcmp(data_, other.data(), length_ * sizeof(CHAR)) == 0;
   }

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template<uint MAXLEN, typename CHAR = char>

uint32_t foedus::assorted::FixedString< MAXLEN, CHAR >::size ( ) const

inlinenoexcept

Returns the length of this string.

Definition at line 164 of file fixed_string.hpp.

164 { return length_; }

template<uint MAXLEN, typename CHAR = char>

std::basic_string<CHAR> foedus::assorted::FixedString< MAXLEN, CHAR >::str ( ) const

inline

Convert to a std::string object.

Definition at line 185 of file fixed_string.hpp.

Referenced by foedus::externalize::Externalizable::add_element(), foedus::assorted::FixedString< 60 >::append(), foedus::assorted::FixedString< 60 >::assign(), foedus::assorted::FixedString< 60 >::c_str(), foedus::log::LogOptions::convert_folder_path_pattern(), foedus::snapshot::SnapshotOptions::convert_folder_path_pattern(), foedus::proc::ProcOptions::convert_shared_library_dir_pattern(), foedus::proc::ProcOptions::convert_shared_library_path_pattern(), foedus::soc::SocOptions::convert_spawn_executable_pattern(), foedus::soc::SocOptions::convert_spawn_ld_library_path_pattern(), foedus::assorted::FixedString< 60 >::FixedString(), foedus::memory::PagePoolPimpl::get_debug_pool_name(), foedus::savepoint::SavepointManagerPimpl::initialize_once(), foedus::externalize::TinyxmlSetter< assorted::FixedString< MAXLEN, CHAR > >::operator()(), and foedus::assorted::FixedString< 60 >::strlen().

                                     {
     return std::basic_string<CHAR>(data_, length_);
   }

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template<uint MAXLEN, typename CHAR = char>

static uint32_t foedus::assorted::FixedString< MAXLEN, CHAR >::strlen ( const char * str )

inlinestaticnoexcept

Definition at line 82 of file fixed_string.hpp.

Referenced by foedus::assorted::FixedString< 60 >::FixedString().

82 { return std::strlen(str); }

foedus::assorted::FixedString::str

std::basic_string< CHAR > str() const

Convert to a std::string object.

Definition: fixed_string.hpp:185

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template<uint MAXLEN, typename CHAR = char>

static uint32_t foedus::assorted::FixedString< MAXLEN, CHAR >::strlen ( const wchar_t * str )

inlinestaticnoexcept

Definition at line 83 of file fixed_string.hpp.

83 { return std::wcslen(str); }

foedus::assorted::FixedString::str

std::basic_string< CHAR > str() const

Convert to a std::string object.

Definition: fixed_string.hpp:185

template<uint MAXLEN, typename CHAR = char>

void foedus::assorted::FixedString< MAXLEN, CHAR >::zero_fill_remaining ( ) const

inlinenoexcept

Sets zeros to unused data_ region.

This is just to make valgrind happy.

Definition at line 174 of file fixed_string.hpp.

Referenced by foedus::storage::StorageManagerPimpl::create_storage().

                                                        {
     if (length_ < MAXLEN) {
       // this is not logically changing the content, so const is the right semantics.
       std::memset(const_cast<char*>(data_ + length_), 0, MAXLEN - length_);
     }
   }

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Friends And Related Function Documentation

template<uint MAXLEN, typename CHAR = char>

std::ostream& operator<<	(	std::ostream &	o,
		const FixedString< MAXLEN, CHAR > &	v
	)

friend

Definition at line 200 of file fixed_string.hpp.

                                                                      {
     o << v.str();
     return o;
   }

Member Data Documentation

template<uint MAXLEN, typename CHAR = char>

const uint32_t foedus::assorted::FixedString< MAXLEN, CHAR >::npos = -1

static

npos is a static member constant value with the greatest possible value for uint32_t.

This value, when used as the value for a len (or sublen) parameter in this object, means "until the end of the string". As a return value, it is usually used to indicate no matches. This constant is defined with a value of -1, which because uint32_t is an unsigned integral type, it is the largest possible representable value for this type.

Definition at line 198 of file fixed_string.hpp.

The documentation for this class was generated from the following file:

/home/shino/foedus_code/foedus-core/include/foedus/assorted/fixed_string.hpp

Detailed Description

template<uint MAXLEN, typename CHAR = char> class foedus::assorted::FixedString< MAXLEN, CHAR >

Usecases

Limitations

Public Member Functions

Static Public Member Functions

Static Public Attributes

Friends

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation

Member Data Documentation

template<uint MAXLEN, typename CHAR = char>
class foedus::assorted::FixedString< MAXLEN, CHAR >