// Cqc.cpp - CUSTOMER QUERY CACHE EMULATOR
//
// MODULE INDEX
// NAME				CONTENTS
// Cqc_c::CqcInsert		Insert a record in the cache
// Cqc_c::CqcRemove		Delete a record from the cache
// Cqc_c::CqcSelect		Select the customers with names that match a key
// Cqc_c::CqcNextCust		Return a pointer to the next customer data
//				structure
//
// MAINTENANCE HISTORY
// DATE		PROGRAMMER AND DETAILS
// 25-09-10	JS	Original
//
//-----------------------------------------------------------------------------

#include <cstdlib>		// C-style standard library
#include <cstring>		// C-style string manipulation functions
#include <string>		// C++ string declarations
#include <set>			// C++ set declarations
#include <iostream>		// C++ I/O stream declarations
using namespace std;		// Expand the standard namespace
#include "Cqc.h"		// Customer query cache declarations

//-----------------------------------------------------------------------------

// INSERT A RECORD IN THE CACHE

void
Cqc_c::CqcInsert (
	const Cust_t	*cust)		// Pointer to a customer data record
{
	// To emulate the fault in the CQC, fail to insert the customer
	// into the cache with a likelihood of 1 in 100,000

	if (lrand48() % 100000 != 1234)
		cqcCustSet.insert (*cust);
}

//-----------------------------------------------------------------------------

// DELETE A RECORD FROM THE CACHE

void
Cqc_c::CqcRemove (
	long		custId)		// Customer identifier to remove
{
	Cust_t		cust;		// Customer row

	// Load the customer identifier into the customer row

	cust.custId = custId;

	// Remove the customer from the set

	if (cqcCustSet.erase (cust) == 0) {
		cerr << "CqcRemove: error: cannot find cust id "
			<< custId << '\n';
		exit (1);
	}
}

//-----------------------------------------------------------------------------

// SELECT THE CUSTOMERS WITH NAMES THAT MATCH A KEY

void
Cqc_c::CqcSelect (
	const char	*key)		// Customer selection key
{
	// For this emulator, only accept select all

	if (strcmp (key, "*") != 0) {
		cerr << "CqcSelect: error: unsupported selection key\n";
		exit (1);
	}

	// Initialise the iterator

	cqcCustIter = cqcCustSet.begin ();
}

//-----------------------------------------------------------------------------

// RETURN A POINTER TO THE NEXT CUSTOMER DATA STRUCTURE

const Cust_t *
Cqc_c::CqcNextCust ()
{
	if (cqcCustIter == cqcCustSet.end())
		return 0;
	return &*cqcCustIter++;
}