lib/datahash/datahash.h

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/*
 * datahash.h
 *
 * Copyright (C) 2004-2006,2008,2009,2010  Thomas A. Vaughan
 * All rights reserved.
 *
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the <organization> nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THOMAS A. VAUGHAN ''AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THOMAS A. VAUGHAN BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *
 * A basic recursive text-based data structure.  Optimized for small-ish
 * objects (a few 10's of KB at most)
 */

#ifndef WAVEPACKET_DATAHASH_H__
#define WAVEPACKET_DATAHASH_H__


// includes --------------------------------------------------------------------
#include "common/common.h"
#include "threadsafe/smart_ptr.h"
#include "threadsafe/threadsafe_multimap.h"


/// \ingroup datahash_top
/*@{*/


////////////////////////////////////////////////////////////////////////////////
///
///     \defgroup datahash Datahash API
///
///     Datahash object plus supporting serialization/deserialization and
///     other utilities.
///
////////////////////////////////////////////////////////////////////////////////
/*@{*/


/// is the given key valid?  there are restrictions on key formats
bool isValidHashKeyName(IN const char * key_name) throw();

/// throw an exception if the given key is not valid
void validateHashKeyName(IN const char * key_name);


enum eHashDataType {
        eHashDataType_String    = 1,    ///< simple text string value
        eHashDataType_Hash      = 2,    ///< subhash

        // keep this last
        eHashDataType_Invalid   = 0
};


class Datahash;         // forward declaration


struct hash_value_t {
        // constructor, manipulators
        hash_value_t(IN const char * txt);
        hash_value_t(IN const std::string& s);
        hash_value_t(IN smart_ptr<Datahash>& h);
        hash_value_t(void) throw() { this->clear(); }

        void clear(void) throw();

        // data fields
        eHashDataType           type;
        std::string             text;
        smart_ptr<Datahash>     hash;
};



////////////////////////////////////////////////////////////////////////////////
///
///     Basic datahash object
///
///     A recursive hash structure that supports key/value access, where there
///     are (in general) multiple values for a given key.  Keys are either
///     simple (a single value is a single string) or complex (a single value
///     is itself another hash).
///
////////////////////////////////////////////////////////////////////////////////
class Datahash : public threadsafe_multimap<std::string, hash_value_t> {
private:
        typedef threadsafe_multimap<std::string, hash_value_t> base_map_t;

public:
        // we overload insert so we can validate keys
        void insert(IN const char * key, IN const hash_value_t& hv) {
                        validateHashKeyName(key);
                        base_map_t::insert(key, hv);
                }

        void insert(IN const std::string& key, IN const hash_value_t& hv) {
                        validateHashKeyName(key.c_str());
                        base_map_t::insert(key, hv);
                }

        // friendly insert routines
        void insert(IN const char * key, IN const char * value) {
                        hash_value_t hv;
                        hv.type = eHashDataType_String;
                        hv.text = value;
                        this->insert(key, hv);
                }

        void insert(IN const char * key, IN smart_ptr<Datahash>& subHash) {
                        hash_value_t hv;
                        hv.type = eHashDataType_Hash;
                        hv.hash = subHash;
                        this->insert(key, hv);
                }

        // const-safe API
        int count(IN const char * key) const throw() {
                        return nonConst()->count(key);
                }

        void getIterator(OUT iterator_t& i) const throw() {
                        nonConst()->getIterator(i);
                }

        void getIterator(IN const char * key, OUT iterator_t& i) const throw() {
                        nonConst()->getIterator(key, i);
                }

        const hash_value_t * getNextElementUnsafe(IO iterator_t& i,
                                        OUT std::string& key) const throw() {
                        return nonConst()->getNextElementUnsafe(i, key);
                }

        const hash_value_t * getNextElementUnsafe(IO iterator_t& i) const throw() {
                        std::string key;
                        return nonConst()->getNextElementUnsafe(i, key);
                }

        // helper factory method
        static smart_ptr<Datahash> create(void) { return new Datahash; }

private:
        // yuck!  Nasty hack to get around const problems.  The threadsafe
        //      multimap is technically never const, because accessors need
        //      to hold the mutex, which involves changing state.  However,
        //      other than temporarily holding the mutex, some operations are
        //      const-safe.  Therefore, this method (and the above const
        //      wrappers) allow some methods to be called as if the hash was
        //      truly const.
        threadsafe_multimap<std::string, hash_value_t> * nonConst(void) const throw() {
                        return (Datahash *) this;
                }
};


/*@}*/  // end of documentation group


#endif  // WAVEPACKET_DATAHASH_H__