ndn.cxx/name-component.h

/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
/*
 * Copyright (c) 2013, Regents of the University of California
 *                     Alexander Afanasyev
 *
 * BSD license, See the LICENSE file for more information
 *
 * Author: Alexander Afanasyev <alexander.afanasyev@ucla.edu>
 */

#ifndef NDN_NAME_COMPONENT_H
#define NDN_NAME_COMPONENT_H

#include "blob.h"

NDN_NAMESPACE_BEGIN

namespace name {

/**
 * @brief Class to representing binary blob of NDN name component
 *
 * This class is based on Blob (std::vector<char>) and just provides several helpers
 * to work with name components, as well as operator to apply canonical
 * ordering on name components
 */
class Component : public Blob
{
public:
  /**
   * @brief Default constructor an empty exclude
   */
  Component ();

  /**
   * @brief Create component from URI encoded string
   * @param uri URI encoded name component (convert escaped with % characters)
   */
  Component (const std::string &uri);

  /**
   * @brief Create component from URI encoded string, with string specified by a pair of iterators
   * @param begin begin iterator pointing to the URI encoded name
   * @param end end iterator
   */
  Component (std::string::const_iterator begin, std::string::const_iterator end);
  
  /**
   * @brief Create component using a binary blob
   * @param buf pointer to first byte of binary blob to store as a name component
   * @param length length of the binary blob
   */
  Component (const void *buf, size_t length);

  /**
   * @brief Apply canonical ordering on component comparison
   * @return 0  They compare equal
   *         <0 If *this comes before other in the canonical ordering
   *         >0 If *this comes after in the canonical ordering
   *
   * @see http://www.ccnx.org/releases/latest/doc/technical/CanonicalOrder.html
   */
  int
  compare (const Component &other) const;
  
  /**
   * @brief Apply canonical ordering on component comparison (less or equal)
   *
   * @see http://www.ccnx.org/releases/latest/doc/technical/CanonicalOrder.html
   */
  inline bool
  operator <= (const Component &other) const;

  /**
   * @brief Apply canonical ordering on component comparison (less)
   *
   * @see http://www.ccnx.org/releases/latest/doc/technical/CanonicalOrder.html
   */
  inline bool
  operator < (const Component &other) const;

  /**
   * @brief Apply canonical ordering on component comparison (greater or equal)
   *
   * @see http://www.ccnx.org/releases/latest/doc/technical/CanonicalOrder.html
   */
  inline bool
  operator >= (const Component &other) const;

  /**
   * @brief Apply canonical ordering on component comparison (greater)
   *
   * @see http://www.ccnx.org/releases/latest/doc/technical/CanonicalOrder.html
   */
  inline bool
  operator > (const Component &other) const;

  ////////////////////////////////////
  // Component construction helpers //
  ////////////////////////////////////

  /**
   * @brief Create component from URI encoded string
   * @param uri URI encoded name component (convert escaped with % characters)
   * @return *this
   */
  Component &
  fromUri (const std::string &uri);

  /**
   * @brief Create component from URI encoded string, with string specified by a pair of iterators
   * @param begin begin iterator pointing to the URI encoded name
   * @param end end iterator
   * @return *this
   */
  Component &
  fromUri (std::string::const_iterator begin, std::string::const_iterator end);
  
  /**
   * @brief Create network-ordered numeric component
   *
   * @param number number to be encoded and added as a component
   * @return *this
   *
   * Number is encoded and added in network order. Tail zero-bytes are not included.
   * For example, if the number is 1, then 1-byte binary blob will be added  0x01.
   * If the number is 256, then 2 binary blob will be added: 0x01 0x01
   *
   * If the number is zero, an empty component will be created
   */
  Component &
  fromNumber (uint64_t number);

  /**
   * @brief Create network-ordered numeric component to the name with marker
   *
   * @param number number to be encoded and added as a component
   * @param marker byte marker, specified by the desired naming convention
   *
   * Currently defined naming conventions of the marker:
   * - 0x00  sequence number
   * - 0xC1  control number
   * - 0xFB  block id
   * - 0xFD  version number
   *
   * This version is almost exactly as appendNumber, with exception that it adds initial marker.
   * The number is formatted in the exactly the same way.
   *
   * @see fromNumber
   */
  Component &
  fromNumberWithMarker (uint64_t number, unsigned char marker);
  
  //////////////////////////////////////////////////////////////////////////////////
  // helpers
  //////////////////////////////////////////////////////////////////////////////////
  
  /**
   * @brief Convert binary blob name component to std::string (no conversion is made)
   * @param comp name component to be converted
   * @see asUriString
   */  
  std::string
  toBlob () const;

  /**
   * @brief Write blob of the name component to the specified output stream
   * @param os output stream
   */
  void
  toBlob (std::ostream &os) const;

  /**
   * @brief Convert binary blob name component to std::string, escaping all non-printable characters in URI format
   * @param comp name component to be converted
   * @see asString
   */
  std::string
  toUri () const;

  /**
   * @brief Write name as URI to the specified output stream
   * @param os output stream
   */
  void
  toUri (std::ostream &os) const;
  
  /**
   * @brief Convert binary blob name component (network-ordered number) to number
   * @param comp name component to be converted
   */  
  uint64_t
  toNumber () const;

  /**
   * @brief Convert binary blob name component (network-ordered number) to number, using appropriate marker from the naming convention
   * @param comp name component to be converted
   * @param marker required marker from the naming convention
   *
   * If the required marker does not exist, an exception will be thrown
   */  
  uint64_t
  toNumberWithMarker (unsigned char marker) const;

  /**
   * @brief Convert binary blob name component, assuming sequence number naming convention (marker = 0x00)
   * @param comp name component to be converted
   * @see asNumberWithMarker
   */
  inline uint64_t
  toSeqNum () const;
  
  /**
   * @brief Convert binary blob name component, assuming control number naming convention (marker = 0xC1)
   * @param comp name component to be converted
   * @see asNumberWithMarker
   */
  inline uint64_t
  toControlNum () const;

  /**
   * @brief Convert binary blob name component, assuming block ID naming convention (marker = 0xFB)
   * @param comp name component to be converted
   * @see asNumberWithMarker
   */
  inline uint64_t
  toBlkId () const;

  /**
   * @brief Convert binary blob name component, assuming time-stamping version naming convention (marker = 0xFD)
   * @param comp name component to be converted
   * @see asNumberWithMarker
   */
  inline uint64_t
  toVersion () const;
};

bool
Component::operator <= (const Component &other) const
{
  return (compare (other) <= 0);
}

bool
Component::operator < (const Component &other) const
{
  return (compare (other) < 0);
}

bool
Component::operator >= (const Component &other) const
{
  return (compare (other) >= 0);
}

bool
Component::operator > (const Component &other) const
{
  return (compare (other) > 0);
}

inline uint64_t
Component::toSeqNum () const
{
  return toNumberWithMarker (0x00);
}
  
inline uint64_t
Component::toControlNum () const
{
  return toNumberWithMarker (0xC1);
}

inline uint64_t
Component::toBlkId () const
{
  return toNumberWithMarker (0xFB);
}

inline uint64_t
Component::toVersion () const
{
  return toNumberWithMarker (0xFD);
}

/**
 * @brief Stream output operator (output in escaped URI format)
 */
inline std::ostream&
operator <<(std::ostream &os, const Component &name)
{
  name.toUri (os);
  return os;
}

} // name

NDN_NAMESPACE_END

#endif // NDN_NAME_COMPONENT_H