// MemoryUsage.h

#ifndef MemoryUsage_H
#define MemoryUsage_H

// Returns the memory usage in bytes.
// Uses /proc.

#include <iosfwd>
#ifndef __CINT__
#include "sys/types.h"
#else
  typedef int pid_t;
#endif

class MemoryUsage {

public:

private:

  pid_t m_pid;
  int m_err;
  size_t m_total;
  size_t m_resident;

public:

  // Constructor for the current process.
  MemoryUsage();

  // Constructor for a given process.
  explicit MemoryUsage(pid_t);

  // Update.
  // Returns zero for success.
  int update();

  // Validity.
  bool is_valid() const;

  // Error code.
  int error() const;

  // Process ID.
  pid_t pid() const;

  // Total process size.
  size_t total() const;

  // Resident in memory.
  size_t resident() const;

};

std::ostream&
operator<<(std::ostream& ostream, const MemoryUsage& rhs);

#endif