DwString -- String class
class DW_EXPORT DwString {
public:
static const size_t npos;
DwString();
DwString(const DwString& aStr, size_t aPos=0, size_t aLen=npos);
DwString(const char* aBuf, size_t aLen);
DwString(const char* aCstr);
DwString(size_t aLen, char aChar);
DwString(char* aBuf, size_t aSize, size_t aStart, size_t aLen);
virtual ~DwString();
DwString& operator = (const DwString& aStr);
DwString& operator = (const char* aCstr);
DwString& operator = (char aChar);
size_t size() const;
size_t length() const;
size_t max_size() const;
void resize(size_t aLen, char aChar);
void resize(size_t aLen);
size_t capacity() const;
void reserve(size_t aSize);
void clear();
DwBool empty() const;
const char& operator [] (size_t aPos) const;
char& operator [] (size_t aPos);
const char& at(size_t aPos) const;
char& at(size_t aPos);
DwString& operator += (const DwString& aStr);
DwString& operator += (const char* aCstr);
DwString& operator += (char aChar);
DwString& append(const DwString& aStr);
DwString& append(const DwString& aStr, size_t aPos, size_t aLen);
DwString& append(const char* aBuf, size_t aLen);
DwString& append(const char* aCstr);
DwString& append(size_t aLen, char aChar);
DwString& assign(const DwString& aStr);
DwString& assign(const DwString& aStr, size_t aPos, size_t aLen);
DwString& assign(const char* aBuf, size_t aLen);
DwString& assign(const char* aCstr);
DwString& assign(size_t aLen, char aChar);
DwString& insert(size_t aPos1, const DwString& aStr);
DwString& insert(size_t aPos1, const DwString& aStr, size_t aPos2,
size_t aLen2);
DwString& insert(size_t aPos1, const char* aBuf, size_t aLen2);
DwString& insert(size_t aPos1, const char* aCstr);
DwString& insert(size_t aPos1, size_t aLen2, char aChar);
DwString& erase(size_t aPos=0, size_t aLen=npos);
DwString& replace(size_t aPos1, size_t aLen1, const DwString& aStr);
DwString& replace(size_t aPos1, size_t aLen1, const DwString& aStr,
size_t aPos2, size_t aLen2);
DwString& replace(size_t aPos1, size_t aLen1, const char* aBuf,
size_t aLen2);
DwString& replace(size_t aPos1, size_t aLen1, const char* aCstr);
DwString& replace(size_t aPos1, size_t aLen1, size_t aLen2, char aChar);
size_t copy(char* aBuf, size_t aLen, size_t aPos=0) const;
void swap(DwString& aStr);
const char* c_str() const;
const char* data() const;
size_t find(const DwString& aStr, size_t aPos=0) const;
size_t find(const char* aBuf, size_t aPos, size_t aLen) const;
size_t find(const char* aCstr, size_t aPos=0) const;
size_t find(char aChar, size_t aPos=0) const;
size_t rfind(const DwString& aStr, size_t aPos=npos) const;
size_t rfind(const char* aBuf, size_t aPos, size_t aLen) const;
size_t rfind(const char* aCstr, size_t aPos=npos) const;
size_t rfind(char aChar, size_t aPos=npos) const;
size_t find_first_of(const DwString& aStr, size_t aPos=0) const;
size_t find_first_of(const char* aBuf, size_t aPos, size_t aLen) const;
size_t find_first_of(const char* aCstr, size_t aPos=0) const;
size_t find_last_of(const DwString& aStr, size_t aPos=npos) const;
size_t find_last_of(const char* aBuf, size_t aPos, size_t aLen) const;
size_t find_last_of(const char* aCstr, size_t aPos=npos) const;
size_t find_first_not_of(const DwString& aStr, size_t aPos=0) const;
size_t find_first_not_of(const char* aBuf, size_t aPos, size_t aLen) const;
size_t find_first_not_of(const char* aCstr, size_t aPos=0) const;
size_t find_last_not_of(const DwString& aStr, size_t aPos=npos) const;
size_t find_last_not_of(const char* aBuf, size_t aPos, size_t aLen) const;
size_t find_last_not_of(const char* aCstr, size_t aPos=npos) const;
DwString substr(size_t aPos=0, size_t aLen=npos) const;
int compare(const DwString& aStr) const;
int compare(size_t aPos1, size_t aLen1, const DwString& aStr) const;
int compare(size_t aPos1, size_t aLen1, const DwString& aStr,
size_t aPos2, size_t aLen2) const;
int compare(const char* aCstr) const;
int compare(size_t aPos1, size_t aLen1, const char* aBuf,
size_t aLen2=npos) const;
virtual const char* ClassName() const;
int ObjectId() const;
void ConvertToLowerCase();
void ConvertToUpperCase();
void Trim();
void WriteTo(ostream& aStrm) const;
int RefCount() const;
void TakeBuffer(char* aBuf, size_t aSize, size_t aStart, size_t aLen);
void ReleaseBuffer(char** aBuf, size_t* aSize, size_t* aStart, size_t* aLen);
void CopyTo(DwString* aStr) const;
protected:
DwStringRep* mRep;
size_t mStart;
size_t mLength;
void _copy();
void _replace(size_t aPos1, size_t aLen1, const char* aBuf, size_t aLen2);
void _replace(size_t aPos1, size_t aLen1, size_t aLen2, char aChar);
friend void mem_free(char*);
public:
virtual void PrintDebugInfo(ostream& aStrm) const;
virtual void CheckInvariants() const;
};
DwString is the workhorse of the MIME++ library. Creating, parsing, or otherwise manipulating MIME messages is basically a matter of manipulating strings. DwString provides all the basic functionality required of a string object, including copying, comparing, concatenating, and so on.
DwString is similar to the string class that is part of the proposed ANSI standard C++ library. Some of the member functions present in the ANSI string are not present in DwString: mostly these are the functions that deal with iterators. DwString also includes some member functions and class utility functions that are not a part of the ANSI string class. These non-ANSI functions are easy to distinguish: they all begin with upper-case letters, and all ANSI functions begin with lower-case letters. The library classes themselves use only the ANSI string functions. At some point in the future, MIME++ will probably allow the option to substitute the ANSI string class for DwString.
DwString makes extensive use of copy-on-write, even when extracting substrings. It is this feature that distiguishes DwString from most other string classes. DwString also handles binary data, which can contain embedded NUL characters.
DwString()
DwString(const DwString& aStr, size_t aPos=0, size_t aLen=npos)
DwString(const char* aBuf, size_t aLen)
DwString(const char* aCstr)
DwString(size_t aLen, char aChar)
DwString(char* aBuf, size_t aSize, size_t aStart, size_t aLen)
The first constructor is the default constructor, which sets the DwString object's contents to be empty.
The second constructor is the copy constructor, which copies at most aLen characters beginning at position aPos from aStr to the new DwString object. It will not copy more characters than what are available in aStr. aPos must be less than or equal to aStr.size().
The third constructor copies aLen characters from the buffer aBuf into the new DwString object. aBuf need not be NUL-terminated and may contain NUL characters.
The fourth constructor copies the contents of the NUL-terminated string aCstr into the new DwString object.
The fifth constructor sets the contents of the new DwString object to be the character aChar repeated aLen times.
The sixth constructor is an advanced constructor that sets the contents of the new DwString object to the aLen characters starting at offset aStart in the buffer aBuf. aSize is the allocated size of aBuf. This constructor is provided for efficiency in setting a new DwString's contents from a large buffer. It is efficient because no copying takes place. Instead, aBuf becomes the buffer used internally by the DwString object, which takes responsibility for deleting the buffer. Because DwString will free the buffer using delete [], the buffer should have been allocated using new. See also: TakeBuffer(), and ReleaseBuffer().
DwString& operator = (const
DwString& aStr)
DwString& operator = (const char* aCstr)
DwString& operator = (char aChar)
Assigns the contents of the operand to this string. aCstr must point to a NUL-terminated array of characters (a C string). Returns *this.
size_t size() const
Returns the number of characters in this string's contents. This member function is identical to length()
size_t length() const
Returns the number of characters in this string's contents. This member function is identical to size()
size_t max_size() const
Returns the maximum length that this string can ever attain.
void resize(size_t aLen, char
aChar)
void resize(size_t aLen)
Changes the length of this string. If the string shortened, the final characters are truncated. If the string is expanded, the added characters will be NULs or the character specified by aChar.
size_t capacity() const
Returns the size of the internal buffer used for this string, which will always be greater than or equal to the length of the string.
void reserve(size_t aSize)
If aSize is greater than the current capacity of this string, this member function will increase the capacity to be at least aSize.
void clear()
Sets this string's contents to be empty.
DwBool empty() const
Returns a true value if and only if the contents of this string are empty.
const char& operator []
(size_t aPos) const
char& operator [] (size_t aPos)
Returns DwString::at(aPos) const or DwString::at(aPos). Note that the non-const version always assumes that the contents will be modified and therefore always copies a shared internal buffer before it returns.
const char& at(size_t aPos) const
char& at(size_t aPos)
Returns the character at position aPos in the string's contents. The non-const version returns an lvalue that may be assigned to. Note that the non-const version always assumes that the contents will be modified and therefore always copies a shared internal buffer before it returns.
DwString& operator +=
(const DwString& aStr)
DwString& operator += (const char* aCstr)
DwString& operator += (char aChar)
Appends the contents of the operand to this string. aCstr must point to a NUL-terminated array of characters (a C string). Returns *this.
DwString& append(const
DwString& aStr)
DwString& append(const DwString& aStr, size_t aPos, size_t aLen)
DwString& append(const char* aBuf, size_t aLen)
DwString& append(const char* aCstr)
DwString& append(size_t aLen, char aChar)
Appends characters to (the end of) this string. Returns *this.
The first version appends all of the characters from aStr.
The second version appends at most aLen characters from aStr beginning at position aPos. aPos must be less than or equal to aStr.size(). The function will not append more characters than what are available in aStr.
The third version appends aLen characters from aBuf, which is not assumed to be NUL-terminated and can contain embedded NULs.
The fourth version appends characters from the NUL-terminated string aCstr.
The fifth version appends aChar repeated aLen times.
DwString& assign(const
DwString& aStr)
DwString& assign(const DwString& aStr, size_t aPos, size_t aLen)
DwString& assign(const char* aBuf, size_t aLen)
DwString& assign(const char* aCstr)
DwString& assign(size_t aLen, char aChar)
Assigns characters to this string. Returns *this.
The first version assigns all of the characters from aStr.
The second version assigns at most aLen characters from aStr beginning at position aPos. aPos must be less than or equal to aStr.size(). The function will not assign more characters than what are available in aStr.
The third version assigns aLen characters from aBuf, which is not assumed to be NUL-terminated and can contain embedded NULs.
The fourth version assigns characters from the NUL-terminated string aCstr.
The fifth version assigns aChar repeated aLen times.
DwString& insert(size_t aPos1,
const DwString& aStr)
DwString& insert(size_t aPos1, const DwString& aStr, size_t aPos2,
size_t aLen2)
DwString& insert(size_t aPos1, const char* aBuf, size_t aLen2)
DwString& insert(size_t aPos1, const char* aCstr)
DwString& insert(size_t aPos1, size_t aLen2, char aChar)
Inserts characters into this string beginning at position aPos1. Returns *this.
The first version inserts all of the characters from aStr.
The second version inserts at most aLen2 characters from aStr beginning at position aPos2. aPos1 must be less than or equal to aStr.size(). The function will not assign more characters than what are available in aStr.
The third version inserts aLen2 characters from aBuf, which is not assumed to be NUL-terminated and can contain embedded NULs.
The fourth version inserts characters from the NUL-terminated string aCstr.
The fifth version inserts aChar repeated aLen2 times.
DwString& erase(size_t aPos=0, size_t aLen=npos)
Erases (removes) at most aLen characters beginning at position aPos from this string. The function will not erase more characters than what are available. Returns *this.
DwString& replace(size_t
aPos1, size_t aLen1, const DwString& aStr)
DwString& replace(size_t aPos1, size_t aLen1, const DwString& aStr,
size_t aPos2, size_t aLen2)
DwString& replace(size_t aPos1, size_t aLen1, const char* aBuf, size_t
aLen2)
DwString& replace(size_t aPos1, size_t aLen1, const char* aCstr)
DwString& replace(size_t aPos1, size_t aLen1, size_t aLen2, char aChar)
Removes aLen1 characters beginning at position aPos1 and inserts other characters. Returns *this.
The first version inserts all of the characters from aStr.
The second version inserts at most aLen2 characters from aStr beginning at position aPos2. aPos1 must be less than or equal to aStr.size(). The function will not assign more characters than what are available in aStr.
The third version inserts aLen2 characters from aBuf, which is not assumed to be NUL-terminated and can contain embedded NULs.
The fourth version inserts characters from the NUL-terminated string aCstr.
The fifth version inserts aChar repeated aLen2 times.
size_t copy(char* aBuf, size_t aLen, size_t aPos=0) const
Copies at most aLen characters beginning at position aPos from this string to the buffer pointed to by aBuf. Returns the number of characters copied.
void swap(DwString& aStr)
Swaps the contents of this string and aStr.
const char* c_str() const
const char* data() const
These member functions permit access to the internal buffer used by the DwString object. c_str() returns a NUL-terminated string suitable for use in C library functions. data() returns a pointer to the internal buffer, which may not be NUL-terminated.
c_str() may copy the internal buffer in order to place the terminating NUL. This is not a violation of the const declaration: it is a logical const, not a bit-representation const. It could have the side effect of invalidating a pointer previously returned by c_str() or data().
The characters in the returned string should not be modified, and should be considered invalid after any call to a non-const member function or another call to c_str().
size_t find(const DwString&
aStr, size_t aPos=0) const
size_t find(const char* aBuf, size_t aPos, size_t aLen) const
size_t find(const char* aCstr, size_t aPos=0) const
size_t find(char aChar, size_t aPos=0) const
Performs a forward search for a sequence of characters in the DwString object. The return value is the position of the sequence in the string if found, or DwString::npos if not found.
The first version searches beginning at position aPos for the sequence of characters in aStr.
The second version searches beginning at position aPos for the sequence of aLen characters in aBuf, which need not be NUL-terminated and can contain embedded NULs.
The third version searches beginning at position aPos for the sequence of characters in the NUL-terminated string aCstr.
The fourth version searches beginning at position aPos for the character aChar.
size_t rfind(const DwString&
aStr, size_t aPos=npos) const
size_t rfind(const char* aBuf, size_t aPos, size_t aLen) const
size_t rfind(const char* aCstr, size_t aPos=npos) const
size_t rfind(char aChar, size_t aPos=npos) const
Performs a reverse search for a sequence of characters in the DwString object. The return value is the position of the sequence in the string if found, or DwString::npos if not found.
The first version searches beginning at position aPos for the sequence of characters in aStr.
The second version searches beginning at position aPos for the sequence of aLen characters in aBuf, which need not be NUL-terminated and can contain embedded NULs.
The third version searches beginning at position aPos for the sequence of characters in the NUL-terminated string aCstr.
The fourth version searches beginning at position aPos for the character aChar.
size_t find_first_of(const
DwString& aStr, size_t aPos=0) const
size_t find_first_of(const char* aBuf, size_t aPos, size_t aLen) const
size_t find_first_of(const char* aCstr, size_t aPos=0) const
Performs a forward search beginning at position aPos for the first occurrence of any character from a specified set of characters. The return value is the position of the character if found, or DwString::npos if not found.
The first version searches for any character in the string aStr.
The second version searches for any of the aLen characters in aBuf.
The third version searches for any character in the NUL-terminated string aCstr.
size_t find_last_of(const
DwString& aStr, size_t aPos=npos) const
size_t find_last_of(const char* aBuf, size_t aPos, size_t aLen) const
size_t find_last_of(const char* aCstr, size_t aPos=npos) const
Performs a reverse search beginning at position aPos for the first occurrence of any character from a specified set of characters. If aPos is greater than or equal to the number of characters in the string, then the search starts at the end of the string. The return value is the position of the character if found, or DwString::npos if not found.
The first version searches for any character in the string aStr.
The second version searches for any of the aLen characters in aBuf.
The third version searches for any character in the NUL-terminated string aCstr.
size_t
find_first_not_of(const DwString& aStr,
size_t aPos=0) const
size_t find_first_not_of(const char* aBuf, size_t aPos, size_t aLen) const
size_t find_first_not_of(const char* aCstr, size_t aPos=0) const
Performs a forward search beginning at position aPos for the first occurrence of any character not in a specified set of characters. The return value is the position of the character if found, or DwString::npos if not found.
The first version searches for any character not in the string aStr.
The second version searches for any character not among the aLen characters in aBuf.
The third version searches for any character not in the NUL-terminated string aCstr.
size_t
find_last_not_of(const DwString& aStr,
size_t aPos=npos) const
size_t find_last_not_of(const char* aBuf, size_t aPos, size_t aLen) const
size_t find_last_not_of(const char* aCstr, size_t aPos=npos) const
Performs a reverse search beginning at position aPos for the first occurrence of any character not in a specified set of characters. If aPos is greater than or equal to the number of characters in the string, then the search starts at the end of the string. The return value is the position of the character if found, or DwString::npos if not found.
The first version searches for any character not in the string aStr.
The second version searches for any character not among the aLen characters in aBuf.
The third version searches for any character not in the NUL-terminated string aCstr.
DwString substr(size_t aPos=0, size_t aLen=npos) const
Returns a string that contains at most aLen characters from the DwString object beginning at position aPos. The returned substring will not contain more characters than what are available in the superstring DwString object.
int compare(const DwString&
aStr) const
int compare(size_t aPos1, size_t aLen1, const DwString& aStr) const
int compare(size_t aPos1, size_t aLen1, const DwString& aStr, size_t
aPos2, size_t aLen2) const
int compare(const char* aCstr) const
int compare(size_t aPos1, size_t aLen1, const char* aBuf, size_t aLen2=npos)
const
These member functions compare a sequence of characters to this DwString object, or a segment of this DwString object. They return -1, 0, or 1, depending on whether this DwString object is less than, equal to, or greater than the compared sequence of characters, respectively.
The first version compares aStr to this string.
The second version compares aStr to the segment of this string of length aLen beginning at position aPos.
The third version compares the {tt aLen2} characters beginning at position aPos2 in aStr with the aLen1 characters beginning at position aPos1 in this DwString object.
The fourth version compares the NUL-terminated string aCstr to this DwString.
The fifth version compares the aLen2 characters in aBuf with this DwString.
virtual const char* ClassName() const
This virtual function returns the name of the class as a NUL-terminated char string.
int ObjectId() const
Returns the unique object id for this DwString.
void
ConvertToLowerCase()
void ConvertToUpperCase()
Converts this DwString object's characters to all lower case or all upper case.
void Trim()
Removes all white space from the beginning and the end of this DwString object. White space characters include ASCII HT, LF, and SPACE.
void WriteTo(ostream& aStrm) const
Writes the contents of this DwString object to the stream aStrm.
int RefCount() const
This advanced member function returns the number of references to the internal buffer used by the DwString object.
void TakeBuffer(char* aBuf, size_t aSize, size_t aStart, size_t aLen)
This advanced member function sets the contents of the DwString object to the aLen characters starting at offset aStart in the buffer aBuf. aSize is the allocated size of aBuf. This member function is provided for efficiency in setting a DwString's contents from a large buffer. It is efficient because no copying takes place. Instead, aBuf becomes the buffer used internally by the DwString object, which takes responsibility for deleting the buffer. Because DwString will free the buffer using delete [], the buffer should have been allocated using new. See also: ReleaseBuffer().
void ReleaseBuffer(char** aBuf, size_t* aSize, size_t* aStart, size_t* aLen)
This advanced member function is the symmetric opposite of TakeBuffer(), to the extent that such an opposite is possible. It provides a way to ``export'' the buffer used internally by the DwString object. Note, however, that because of the copy-on-modify feature of DwString, the DwString object may not have sole ownership of its internal buffer. When that is case, ReleaseBuffer() will return a copy of the buffer. You can check to see if the internal buffer is shared by calling RefCount(). On return from this member function, the DwString object will have valid, but empty, contents. It is recommended that you use this function only on rare occasions where you need to export efficiently a large buffer.
void CopyTo(DwString* aStr) const
This advanced member function copies this DwString object to aStr. This member function is different from the assignment operator, because it physically copies the buffer instead of just duplicating a reference to it.
virtual void PrintDebugInfo(ostream& aStrm) const
Prints debugging information about the object to aStrm.
This member function is available only in the debug version of the library.
virtual void CheckInvariants() const
Aborts if one of the invariants of the object fails. Use this member function to track down bugs.
This member function is available only in the debug version of the library.
static const size_t npos
npos is assigned the value (size_t)-1.