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/* string.cpp
*
* Note: http://msdn.microsoft.com/en-us/magazine/cc163742.aspx
*
*/
#include "string.h"
#include <sstream>
MyString::MyString(int len) : str_(new char[len + 1]), length_(len)
{
this->count++;
}
MyString::MyString(const char *str) : str_(new char[strlen(str)+1]), length_(strlen(str))
{
strcpy(str_, str);
this->count++;
}
MyString::MyString(const MyString& str) : str_(new char[str.length_ + 1]),
length_(str.length_)
{
strcpy(str_, str.str_);
this->count++;
}
MyString& MyString::operator=(const MyString& rhs)
{
/* don't do anything if object assigns itself */
if (this == &rhs)
return *this;
length_ = rhs.length_;
delete[] str_;
str_ = new char[ length_ + 1];
strcpy(str_, rhs.str_);
/* assignment operator requires this */
return *this;
}
MyString::~MyString()
{
delete[] str_;
this->count--;
}
int MyString::indexOf(char ch, int pos) const
{
while (pos < length_)
{
if (str_[pos] == ch)
return pos;
pos++;
}
return -1;
}
/* define this field only once, .h is not the best place */
size_t MyString::count = 0;
bool MyString::isSubstring(const MyString& str) const
{
if (length_ < str.length_)
return false;
int i, j, temp;
for (i = 0; i < length_; i++)
{
j = 0;
temp = i;
while ((j < str.length_) && (str_[temp] == str.str_[j]))
{
temp++;
j++;
}
if (j == str.length_)
return true;
}
return false;
}
/* might seem redundant since constructor can create an object from char array
* and call other isSubstring method that takes in MyString type
*/
bool MyString::isSubstring(const char *str) const
{
int i, j, k;
for (i = 0; i < length_; i++)
{
j = i;
k = 0;
while (str_[j++] == str[k++])
;
if (str[k-1] == '\0')
return true;
}
return false;
}
/* there are few ways to implement this */
MyString& MyString::concat(const MyString& str)
{
/* right way to do this would be to use realloc and double the buffer each
* we append something (if it's full)
*/
MyString ret(length_ + str.length_);
strcpy(ret.str_, str_);
strcat(ret.str_, str.str_);
return (*this = ret);
}
MyString& MyString::concat(const char *str)
{
char *newstr = new char[length_ + strlen(str) + 1];
strcpy(newstr, str_);
strcpy(newstr + length_, str);
delete[] str_;
length_ += strlen(str);
str_ = newstr;
return *this;
}
bool operator==(const MyString& lhs, const MyString& rhs)
{
if (lhs.length_ != rhs.length_)
return false;
if (strcmp(lhs.str_, rhs.str_) == 0)
return true;
else
return false;
}
bool operator!=(const MyString& lhs, const MyString& rhs)
{
return !(lhs == rhs);
}
/* right now I think the reference is used to avoid returning copy of ostream
* so when calls are chained up we work on one ostream object only
*
* this function is in global scope, it is friend'ed to allow us access to data
* members of calss MyString
*/
std::ostream& operator<<(std::ostream& ostr, const MyString& rhs)
{
return (ostr << rhs.str_);
}
/* unary operator operate on one operand, itself! */
bool MyString::operator!(void) const
{
return (this->length_ == 0);
}
char& MyString::operator[](int i)
{
/* references need to point to valid objects, all hell could breaks loose */
return this->str_[i];
}
char MyString::operator[](int i) const
{
if (i < 0 || i > this->length_ - 1)
return 0;
else
return this->str_[i];
}
MyString::operator char*()
{
char *ret = new char[this->length_ + 1];
if (ret)
{
strcpy(ret, this->str_);
return ret;
}
else
return NULL;
}
MyString::operator const char*() const
{
return this->str_;
}
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