Generic Circular Buffer and tests, C++

CircBuf.h

#include <stdexcept>

/* 
   T must implement operator=, copy ctor 
*/

template<typename T> class CircBuf {
  // don't use default ctor
  CircBuf();

  const int size;
  T *data;
  int front;
  int count;
public:
  CircBuf(int);
  ~CircBuf();

  bool empty() { return count == 0; }
  bool full() { return count == size; }
  bool add(const T&);
  bool remove(T*);
};

template<typename T> CircBuf<T>::CircBuf(int sz): size(sz) {
  if (sz==0) throw std::invalid_argument("size cannot be zero");
  data = new T[sz];
  front = 0;
  count = 0;
}
template<typename T> CircBuf<T>::~CircBuf() {
  delete data;
}

// returns true if add was successful, false if the buffer is already full
template<typename T> bool CircBuf<T>::add(const T &t) {
  if ( full() ) {
    return false;
  } else {
    // find index where insert will occur
    int end = (front + count) % size;
    data[end] = t;
    count++;
    return true;
  }
}

// returns true if there is something to remove, false otherwise
template<typename T> bool CircBuf<T>::remove(T *t) {
  if ( empty() ) {
    return false;
  } else {
    *t = data[front];
    
    front = front == size ? 0 : front + 1;
    count--;
    return true;
  }
}

gcc.errors

opaque rcv();
for (int i=0; i<size; i++) {
  if ( c.remove(&rcv)) {
    ....
    ....

tests.cpp: In function ‘bool opaque_fill_test(int)’:
tests.cpp:97:23: error: no matching function for call to ‘CircBuf<opaque>::remove(opaque (*)())’
compilation terminated due to -Wfatal-errors.

opaque rcv();
opaque* p = &rcv;
for (int i=0; i<size; i++) {
  if ( c.remove(p)) {
    ...
    ...

tests.cpp: In function ‘bool opaque_fill_test(int)’:
tests.cpp:96:16: error: cannot convert ‘opaque (*)()’ to ‘opaque*’ in initialization
compilation terminated due to -Wfatal-errors.

makefile

FLAGS = -g -ansi -pedantic-errors -Wfatal-errors

all:
	g++ $(FLAGS) tests.cpp -o test
clean:
	rm -rf test

tests.cpp

#include "CircBuf.h"

#include <iostream>
#include <stdexcept>
#include <vector>
#include <cstdlib>

using namespace std;

// top-level tests
bool TEST_fill();

// test utils
template <typename T> bool fill_test(int size);

int main() {
  TEST_fill();

  return EXIT_SUCCESS;
}

// OPQSIZE >= sizeof(int) + 1;
// 64 bytes is typical cache line size in x86
const int OPQSIZE = 64;
struct opaque {
  int id;
  char data[OPQSIZE - sizeof(int)];
  // not copying data[] should speed up copying many opaque
  opaque(int n): id(n) {} 
  opaque operator=(const opaque &o) { this->id = o.id; }
};

bool TEST_fill() {
  try {
    CircBuf<int> inv(0);
    cout << "fill_test(0) should throw invalid_argument" << endl;
    return false;
  } catch (invalid_argument &e) {
    // do nothing, fill_test(0) should throw invalid_argument
  }

  const int increments[] = {64, 32768, 200000, 100000000};
  int sz = sizeof(increments) / sizeof(int);
  for (int i=0; i < sz; i++) {
    if ( !fill_test<int>( increments[i] ) ) {
      cout << "fill_test<int>(" << increments[i] << ") failed" << endl;
      return false;
    } 
  }

  for (int i=0; i < sz; i++) {
    if ( !fill_test<opaque>( increments[i] ) ) {
      cout << "fill_test<opaque>(" << increments[i] << ") failed" << endl;
      return false;
    } 
  }

  return true;
}

bool int_fill_test(int size) {
  CircBuf<int> c(size);
  for (int i=0; i<size; i++) {
    if ( !c.add(i) ) {
      cout << "add fail at i=" << i << endl;
      return false;
    }
  }

  int rcv = 0;
  for (int i=0; i<size; i++) {
    if ( c.remove(&rcv)) {
      if (rcv != i ) {
	cout << "wrong value: " << rcv << " "
	     << "should be: " << i << endl;
	return false;
      }
    } else {
      cout << "remove fail at i=" << rcv << endl;
      return false;
    }
  }
  return true;
}

bool opaque_fill_test(int size) {
  CircBuf<opaque> c(size);
  for (int i=0; i<size; i++) {
    if ( !c.add( opaque(i))) {
      cout << "add fail at i=" << i << endl;
      return false;
    }
  }

  opaque rcv();
  for (int i=0; i<size; i++) {
    if ( c.remove(&rcv)) {
      if (rcv.id != i ) {
	cout << "wrong value: " << rcv << " "
	     << "should be: " << i << endl;
	return false;
      }
    } else {
      cout << "remove fail at i=" << rcv << endl;
      return false;
    }
  }
  return true;
}

Nasty bug in line 55 of CircBuf.h. It should be front = (front == size - 1) ? 0 : front + 1;. Very good class though!