//===-- ConstString.h -------------------------------------------*- C++ -*-===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// #ifndef liblldb_ConstString_h_ #define liblldb_ConstString_h_ #if defined(__cplusplus) #include <assert.h> #include "lldb/lldb-private.h" #include "llvm/ADT/StringRef.h" namespace lldb_private { //---------------------------------------------------------------------- /// @class ConstString ConstString.h "lldb/Core/ConstString.h" /// @brief A uniqued constant string class. /// /// Provides an efficient way to store strings as uniqued strings. After /// the strings are uniqued, finding strings that are equal to one /// another is very fast as just the pointers need to be compared. It /// also allows for many common strings from many different sources to /// be shared to keep the memory footprint low. /// /// No reference counting is done on strings that are added to the /// string pool, once strings are added they are in the string pool for /// the life of the program. //---------------------------------------------------------------------- class ConstString { public: //------------------------------------------------------------------ /// Default constructor /// /// Initializes the string to an empty string. //------------------------------------------------------------------ ConstString (): m_string (NULL) { } //------------------------------------------------------------------ /// Copy constructor /// /// Copies the string value in \a rhs into this object. /// /// @param[in] rhs /// Another string object to copy. //------------------------------------------------------------------ ConstString (const ConstString& rhs) : m_string (rhs.m_string) { } explicit ConstString (const llvm::StringRef &s); //------------------------------------------------------------------ /// Construct with C String value /// /// Constructs this object with a C string by looking to see if the /// C string already exists in the global string pool. If it doesn't /// exist, it is added to the string pool. /// /// @param[in] cstr /// A NULL terminated C string to add to the string pool. //------------------------------------------------------------------ explicit ConstString (const char *cstr); //------------------------------------------------------------------ /// Construct with C String value with max length /// /// Constructs this object with a C string with a length. If /// \a max_cstr_len is greater than the actual length of the string, /// the string length will be truncated. This allows substrings to /// be created without the need to NULL terminate the string as it /// is passed into this function. /// /// @param[in] cstr /// A pointer to the first character in the C string. The C /// string can be NULL terminated in a buffer that contains /// more characters than the length of the stirng, or the /// string can be part of another string and a new substring /// can be created. /// /// @param[in] max_cstr_len /// The max length of \a cstr. If the string length of \a cstr /// is less than \a max_cstr_len, then the string will be /// truncated. If the string length of \a cstr is greater than /// \a max_cstr_len, then only max_cstr_len bytes will be used /// from \a cstr. //------------------------------------------------------------------ explicit ConstString (const char *cstr, size_t max_cstr_len); //------------------------------------------------------------------ /// Destructor /// /// Since constant string values are currently not reference counted, /// there isn't much to do here. //------------------------------------------------------------------ ~ConstString () { } //---------------------------------------------------------------------- /// C string equality binary predicate function object for ConstString /// objects. //---------------------------------------------------------------------- struct StringIsEqual { //-------------------------------------------------------------- /// C equality test. /// /// Two C strings are equal when they are contained in ConstString /// objects when their pointer values are equal to each other. /// /// @return /// Returns \b true if the C string in \a lhs is equal to /// the C string value in \a rhs, \b false otherwise. //-------------------------------------------------------------- bool operator()(const char* lhs, const char* rhs) const { return lhs == rhs; } }; //------------------------------------------------------------------ /// Convert to bool operator. /// /// This allows code to check a ConstString object to see if it /// contains a valid string using code such as: /// /// @code /// ConstString str(...); /// if (str) /// { ... /// @endcode /// /// @return /// /b True this object contains a valid non-empty C string, \b /// false otherwise. //------------------------------------------------------------------ operator bool() const { return m_string && m_string[0]; } //------------------------------------------------------------------ /// Assignment operator /// /// Assigns the string in this object with the value from \a rhs. /// /// @param[in] rhs /// Another string object to copy into this object. /// /// @return /// A const reference to this object. //------------------------------------------------------------------ const ConstString& operator = (const ConstString& rhs) { m_string = rhs.m_string; return *this; } //------------------------------------------------------------------ /// Equal to operator /// /// Returns true if this string is equal to the string in \a rhs. /// This operation is very fast as it results in a pointer /// comparison since all strings are in a uniqued in a global string /// pool. /// /// @param[in] rhs /// Another string object to compare this object to. /// /// @return /// @li \b true if this object is equal to \a rhs. /// @li \b false if this object is not equal to \a rhs. //------------------------------------------------------------------ bool operator == (const ConstString& rhs) const { // We can do a pointer compare to compare these strings since they // must come from the same pool in order to be equal. return m_string == rhs.m_string; } //------------------------------------------------------------------ /// Not equal to operator /// /// Returns true if this string is not equal to the string in \a rhs. /// This operation is very fast as it results in a pointer /// comparison since all strings are in a uniqued in a global string /// pool. /// /// @param[in] rhs /// Another string object to compare this object to. /// /// @return /// @li \b true if this object is not equal to \a rhs. /// @li \b false if this object is equal to \a rhs. //------------------------------------------------------------------ bool operator != (const ConstString& rhs) const { return m_string != rhs.m_string; } bool operator < (const ConstString& rhs) const; //------------------------------------------------------------------ /// Get the string value as a C string. /// /// Get the value of the contained string as a NULL terminated C /// string value. /// /// If \a value_if_empty is NULL, then NULL will be returned. /// /// @return /// Returns \a value_if_empty if the string is empty, otherwise /// the C string value contained in this object. //------------------------------------------------------------------ const char * AsCString(const char *value_if_empty = NULL) const { if (m_string == NULL) return value_if_empty; return m_string; } //------------------------------------------------------------------ /// Get the string value as a llvm::StringRef /// /// @return /// Returns a new llvm::StringRef object filled in with the /// needed data. //------------------------------------------------------------------ llvm::StringRef GetStringRef () const { return llvm::StringRef (m_string, GetLength()); } //------------------------------------------------------------------ /// Get the string value as a C string. /// /// Get the value of the contained string as a NULL terminated C /// string value. Similar to the ConstString::AsCString() function, /// yet this function will always return NULL if the string is not /// valid. So this function is a direct accessor to the string /// pointer value. /// /// @return /// Returns NULL the string is invalid, otherwise the C string /// value contained in this object. //------------------------------------------------------------------ const char * GetCString () const { return m_string; } //------------------------------------------------------------------ /// Get the length in bytes of string value. /// /// The string pool stores the length of the string, so we can avoid /// calling strlen() on the pointer value with this function. /// /// @return /// Returns the number of bytes that this string occupies in /// memory, not including the NULL termination byte. //------------------------------------------------------------------ size_t GetLength () const; //------------------------------------------------------------------ /// Clear this object's state. /// /// Clear any contained string and reset the value to the an empty /// string value. //------------------------------------------------------------------ void Clear () { m_string = NULL; } //------------------------------------------------------------------ /// Compare two string objects. /// /// Compares the C string values contained in \a lhs and \a rhs and /// returns an integer result. /// /// NOTE: only call this function when you want a true string /// comparision. If you want string equality use the, use the == /// operator as it is much more efficient. Also if you want string /// inequality, use the != operator for the same reasons. /// /// @param[in] lhs /// The Left Hand Side const ConstString object reference. /// /// @param[in] rhs /// The Right Hand Side const ConstString object reference. /// /// @return /// @li -1 if lhs < rhs /// @li 0 if lhs == rhs /// @li 1 if lhs > rhs //------------------------------------------------------------------ static int Compare (const ConstString& lhs, const ConstString& rhs); //------------------------------------------------------------------ /// Dump the object description to a stream. /// /// Dump the string value to the stream \a s. If the contained string /// is empty, print \a value_if_empty to the stream instead. If /// \a value_if_empty is NULL, then nothing will be dumped to the /// stream. /// /// @param[in] s /// The stream that will be used to dump the object description. /// /// @param[in] value_if_empty /// The value to dump if the string is empty. If NULL, nothing /// will be output to the stream. //------------------------------------------------------------------ void Dump (Stream *s, const char *value_if_empty = NULL) const; //------------------------------------------------------------------ /// Dump the object debug description to a stream. /// /// @param[in] s /// The stream that will be used to dump the object description. //------------------------------------------------------------------ void DumpDebug (Stream *s) const; //------------------------------------------------------------------ /// Test for empty string. /// /// @return /// @li \b true if the contained string is empty. /// @li \b false if the contained string is not empty. //------------------------------------------------------------------ bool IsEmpty () const { return m_string == NULL || m_string[0] == '\0'; } //------------------------------------------------------------------ /// Set the C string value. /// /// Set the string value in the object by uniquing the \a cstr /// string value in our global string pool. /// /// If the C string already exists in the global string pool, it /// finds the current entry and returns the existing value. If it /// doesn't exist, it is added to the string pool. /// /// @param[in] cstr /// A NULL terminated C string to add to the string pool. //------------------------------------------------------------------ void SetCString (const char *cstr); void SetString (const llvm::StringRef &s); //------------------------------------------------------------------ /// Set the C string value and its mangled counterpart. /// /// Object files and debug sybmols often use mangled string to /// represent the linkage name for a symbol, function or global. /// The string pool can efficiently store these values and their /// counterparts so when we run into another instance of a mangled /// name, we can avoid calling the name demangler over and over on /// the same strings and then trying to unique them. /// /// @param[in] demangled /// The demangled C string to correlate with the \a mangled /// name. /// /// @param[in] mangled /// The already uniqued mangled ConstString to correlate the /// soon to be uniqued version of \a demangled. //------------------------------------------------------------------ void SetCStringWithMangledCounterpart (const char *demangled, const ConstString &mangled); //------------------------------------------------------------------ /// Retrieve the mangled or demangled counterpart for a mangled /// or demangled ConstString. /// /// Object files and debug sybmols often use mangled string to /// represent the linkage name for a symbol, function or global. /// The string pool can efficiently store these values and their /// counterparts so when we run into another instance of a mangled /// name, we can avoid calling the name demangler over and over on /// the same strings and then trying to unique them. /// /// @param[in] counterpart /// A reference to a ConstString object that might get filled in /// with the demangled/mangled counterpart. /// /// @return /// /b True if \a counterpart was filled in with the counterpart /// /b false otherwise. //------------------------------------------------------------------ bool GetMangledCounterpart (ConstString &counterpart) const; //------------------------------------------------------------------ /// Set the C string value with length. /// /// Set the string value in the object by uniquing \a cstr_len bytes /// starting at the \a cstr string value in our global string pool. /// If trim is true, then \a cstr_len indicates a maximum length of /// the CString and if the actual length of the string is less, then /// it will be trimmed. /// /// If the C string already exists in the global string pool, it /// finds the current entry and returns the existing value. If it /// doesn't exist, it is added to the string pool. /// /// @param[in] cstr /// A NULL terminated C string to add to the string pool. /// /// @param[in] cstr_len /// The maximum length of the C string. //------------------------------------------------------------------ void SetCStringWithLength (const char *cstr, size_t cstr_len); //------------------------------------------------------------------ /// Set the C string value with the minimum length between /// \a fixed_cstr_len and the actual length of the C string. This /// can be used for data structures that have a fixed length to /// store a C string where the string might not be NULL terminated /// if the string takes the entire buffer. //------------------------------------------------------------------ void SetTrimmedCStringWithLength (const char *cstr, size_t fixed_cstr_len); //------------------------------------------------------------------ /// Get the memory cost of this object. /// /// Return the size in bytes that this object takes in memory. This /// returns the size in bytes of this object, which does not include /// any the shared string values it may refer to. /// /// @return /// The number of bytes that this object occupies in memory. /// /// @see ConstString::StaticMemorySize () //------------------------------------------------------------------ size_t MemorySize () const { return sizeof(ConstString); } //------------------------------------------------------------------ /// Get the size in bytes of the current global string pool. /// /// Reports the the size in bytes of all shared C string values, /// containers and any other values as a byte size for the /// entire string pool. /// /// @return /// The number of bytes that the global string pool occupies /// in memory. //------------------------------------------------------------------ static size_t StaticMemorySize (); protected: //------------------------------------------------------------------ // Member variables //------------------------------------------------------------------ const char *m_string; }; //------------------------------------------------------------------ /// Stream the string value \a str to the stream \a s //------------------------------------------------------------------ Stream& operator << (Stream& s, const ConstString& str); } // namespace lldb_private #endif // #if defined(__cplusplus) #endif // liblldb_ConstString_h_