ino.hh

COPE the first practical network coding scheme which is developped on click

// -*- c-basic-offset: 4; related-file-name: "../../lib/ino.cc" -*-
#ifndef CLICK_INO_HH
#define CLICK_INO_HH
#include <click/string.hh>
CLICK_DECLS
class Router;

// NB: inode number 0 is reserved for the system.
#define INO_DIRTYPE(ino)		((ino) >> 28)
#define INO_ELEMENTNO(ino)		((int)((ino) & 0xFFFFU) - 1)
#define INO_HANDLERNO(ino)		((((ino) & 0xFFFFU) ? 0 : Router::FIRST_GLOBAL_HANDLER) + (((ino) >> 16) & 0x7FFFU))
#define INO_DT_H			0x1U /* handlers only */
#define INO_DT_N			0x2U /* names; >= 2 -> has names */
#define INO_DT_HN			0x3U /* handlers + names */
#define INO_DT_GLOBAL			0x4U /* handlers + names + all #s */
#define INO_DT_HAS_H(ino)		(INO_DIRTYPE((ino)) != INO_DT_N)
#define INO_DT_HAS_N(ino)		(INO_DIRTYPE((ino)) >= INO_DT_N)
#define INO_DT_HAS_U(ino)		(INO_DIRTYPE((ino)) == INO_DT_GLOBAL)

#define INO_MKHANDLER(e, hi)		((((hi) & 0x7FFFU) << 16) | (((e) + 1) & 0xFFFFU) | 0x80000000U)
#define INO_MKHDIR(e)			((INO_DT_H << 28) | (((e) + 1) & 0xFFFFU))
#define INO_MKNDIR(e)			((INO_DT_N << 28) | (((e) + 1) & 0xFFFFU))
#define INO_MKHNDIR(e)			((INO_DT_HN << 28) | (((e) + 1) & 0xFFFFU))
#define INO_GLOBALDIR			(INO_DT_GLOBAL << 28)
#define INO_ISHANDLER(ino)		(((ino) & 0x80000000U) != 0)

#define INO_DEBUG			0

class ClickIno { public:

    void initialize();
    void cleanup();

    uint32_t generation() const		{ return _generation; }
    
    // All operations should be called with a configuration lock held.
    inline int prepare(Router*, uint32_t);
    int nlink(ino_t);
    ino_t lookup(ino_t dir, const String& component);

    // readdir doesn't handle '.' or '..'.
    // It returns 0 for "filldir failed, have more", 1 for "out", <0 on error.
    typedef bool (*filldir_t)(const char* name, int name_len, ino_t ino, int dirtype, uint32_t f_pos, void* thunk);
    int readdir(ino_t dir, uint32_t& f_pos, filldir_t, void* thunk);

#if INO_DEBUG
    String info() const;
#endif

    struct Entry {
	// Name of this entry.
	String name;

	// Corresponding eindex plus 1. Might be larger than the number of
	// elements in the router, because of fake directories added for
	// compound "elements".
	uint16_t elementno_plus1;

	// '_x[i].xindex' equals the index in _x of the entry for element
	// number 'i - 1'.
	uint16_t xindex;

	// Number of child entries. 'name' is guaranteed to be a prefix of
	// every child entry.
	uint16_t skip;

	// See enum below. X_FAKE is true on fake directories added for
	// compound elements; X_HANDLER_CONFLICT is true if this element name
	// conflicts with a handler; X_SUBDIR_CONFLICTS_CALCULATED is true if
	// we've already checked for name conflicts on this element's
	// children.
	uint16_t flags;
    };
    
  private:

    enum { X_FAKE = 1, X_HANDLER_CONFLICT = 2, X_SUBDIR_CONFLICTS_CALCULATED = 4 };
    
    Entry* _x;
    int _nentries;
    int _cap;
    Router* _router;
    uint32_t _generation;

    inline int xindex(int elementno) const;
    inline int next_xindex(int elementno) const;
    inline int elementno(int xindex) const;

    int name_search(const String& n, int first_xi, int last_xi, int name_offset) const;
    
    int grow(int min_size);
    void calculate_handler_conflicts(int);
    int true_prepare(Router*, uint32_t);

};


inline int
ClickIno::prepare(Router* router, uint32_t generation)
{
    if (generation != _generation)
	return true_prepare(router, generation);
    else
	return 0;
}

inline int
ClickIno::xindex(int elementno) const
{
    assert(elementno >= -1 && elementno < _nentries - 1);
    return _x[elementno + 1].xindex;
}

inline int
ClickIno::next_xindex(int elementno) const
{
    int xi = xindex(elementno);
    return xi + _x[xi].skip + 1;
}

inline int
ClickIno::elementno(int xindex) const
{
    return _x[xindex].elementno_plus1 - 1;
}

CLICK_ENDDECLS
#endif