// dstring.cpp (203 lines)
//
// Coded by: Joseph Bertolami
// Email: jbertola@uci.edu
//
// ICS 175A, Winter 2004
//

// This file defines the basic lowest-level string object used for
// the entire project. DString allows the other programmers to
// abstract from the character pointer level and provides high
// level functionality needed for this project.

#include "dstring.h"

// Author: Joseph Bertolami
// Email: jbertola@uci.edu
DString::DString(const DString & rhs)
{
	buffer = strdup(rhs.buffer);
	length = rhs.length;
}

// Author: Joseph Bertolami
// Email: jbertola@uci.edu
DString::DString(const char *str) 
{ 
	buffer= strdup(str); 
	length=(unsigned)strlen(str);
}

// Author: Joseph Bertolami
// Email: jbertola@uci.edu
DString::~DString() { if ( buffer ) free(buffer); buffer=NULL; length=0; }

// operator = 
// assigns rhs to *this
/*
char * DString::operator = (DString & rhs)
{
	if ( buffer ) free( buffer );
	buffer = strdup(rhs.buffer);
	length = rhs.length;
	return buffer;
}
*/

// Author: Joseph Bertolami
// Email: jbertola@uci.edu
DString DString::operator = (const DString & rhs)
{
	if ( buffer ) free( buffer );
	buffer = strdup(rhs.buffer);
	length = rhs.length;
	return *this;
}

// Author: Joseph Bertolami
// Email: jbertola@uci.edu
void DString::set(const char *text)
{
	if ( buffer ) free(buffer);
		buffer = strdup(text);
		length = strlen(text);

}

// Author: Joseph Bertolami
// Email: jbertola@uci.edu
DString DString::operator + (DString & rhs)
{
	// operator +
	// cat's rhs onto *this

	char * temp = (char*) malloc(strlen(buffer) + strlen(rhs.buffer) + 1);
	memcpy(temp, buffer, strlen(buffer));
	memcpy(temp+strlen(buffer), rhs.buffer, strlen(rhs.buffer));
	temp[strlen(buffer)+strlen(rhs.buffer)] = '\0';	
	DString tmp(temp);
	return tmp;
}	

// Author: Joseph Bertolami
// Email: jbertola@uci.edu
// operator +=
DString DString::operator += (DString & rhs)
{
	*this = *this + rhs;
	return *this;
}

// Author: Joseph Bertolami
// Email: jbertola@uci.edu
DString DString::operator += (char * rhs)
{
	::strcat(buffer, rhs);
	length += strlen(rhs);
	return *this;
}

// Author: Joseph Bertolami
// Email: jbertola@uci.edu
//
// char *substr
// returns a pointer to the first occurrence of
// string 'token' in string 'str'
char * DString::substr(const char *token, const char *str)
{
	return strstr(str, token);
}	


// Author: Joseph Bertolami
// Email: jbertola@uci.edu
// Edited by: Jeff Weiss, Nicholas Urrea
DString DString::substr(int start, int end)
{
	DString newstr;
	if ( end < start ) 
	{
		printf("DString::substr (error) end < start\n");
		return newstr;
	}

	char *temp = new char[(end-start)+1];	// define valid new length
	memcpy(temp, buffer+start, end-start);
	temp[(end-start)]='\0';					// add end char
	newstr.set(temp);
	delete [] temp;
	newstr.length=(end-start);				// re-define length
	return newstr;
}

// Author: Joseph Bertolami
// Email: jbertola@uci.edu
bool DString::operator ==(DString & rhs)
{
	if ( 0 == ::strcmp(buffer, rhs.buffer) )
		return true;

	return false;
}

// Author: Joseph Bertolami
// Email: jbertola@uci.edu
char DString::operator [](unsigned int index)
{
	if ( index < 0 || index >= length )	return 0;
	return buffer[index];
}

// Author: Joseph Bertolami
// Email: jbertola@uci.edu
unsigned DString::nsubstr(const char *token, const char *str)
{
	// unsigned nsubstr
	// returns number of occurrences of substring token
	// in string 'str'

	unsigned count = 0;
	char *marker = NULL;
	char *temp = strdup(str);

	while ( (marker = substr(token,temp)) != NULL )
	{
		temp = marker + strlen(token) + 1;
		count++;
	}

	return count;
}

// Author: Joseph Bertolami
// Email: jbertola@uci.edu
int DString::strcmp(DString & string2)
{
	// returns 0 if no match
	// note, if comparisons begin coming up wrong,
	// slow this function down by enforcing ascii
	// comparison to avoid erroneous data

	if ( length != string2.length ) return 0;
	for ( unsigned i = 0; i < length; i++ )
	{
		if ( buffer[i] ^ string2[i] )
			return 0;
	}

	return 1;
}

// Author: Joseph Bertolami
// Email: jbertola@uci.edu
char *		DString::data()		{	return buffer;						}
void		DString::clear()	{	if ( buffer ) free( buffer );		}
unsigned	DString::size()		{	return length;						}
void		DString::print()	{	printf("%s\n", buffer);				}

// Edited by: Vishakh
void DString::setChar(char c, int index)
{
	buffer[index] = c;
}