WriteUtil.cpp

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/**
 * MOAB, a Mesh-Oriented datABase, is a software component for creating,
 * storing and accessing finite element mesh data.
 *
 * Copyright 2004 Sandia Corporation.  Under the terms of Contract
 * DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government
 * retains certain rights in this software.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 */

#ifdef WIN32
#pragma warning( disable : 4786 )
#endif

#include "WriteUtil.hpp"
#include "moab/Core.hpp"
#include "moab/Error.hpp"
#include "SequenceManager.hpp"
#include "ElementSequence.hpp"
#include "VertexSequence.hpp"
#include "AEntityFactory.hpp"
#include "MBTagConventions.hpp"
#include "RangeSeqIntersectIter.hpp"
#include "MeshSetSequence.hpp"

#include <sys/types.h>
#include <sys/stat.h>
#include <cerrno>
#include <cassert>
#include <iostream>

#ifdef WIN32
#define stat _stat
#else
#include <unistd.h>
#endif

namespace moab
{

WriteUtil::WriteUtil( Core* mdb ) : WriteUtilIface(), mMB( mdb ) {}

//! Check if the specified file already exists.
//! Returns MB_SUCCESS if file does not exist, MB_ALREADY_ALLOCATED
//! if file does exist, or MB_FAILURE for some other error condition.
ErrorCode WriteUtil::check_doesnt_exist( const char* file_name )
{
    struct stat s;
    if( 0 == stat( file_name, &s ) )
    {
        MB_SET_ERR( MB_ALREADY_ALLOCATED, file_name << ": file already exists" );
    }
    else if( errno == ENOENT )
        return MB_SUCCESS;
    else
        return MB_FAILURE;
}

//! Gather all entities in the mesh, or in the sets specified
ErrorCode WriteUtil::gather_entities( Range& all_ents,
                                      /**< range in which entities are returned */
                                      const EntityHandle* ent_sets,
                                      /**< entity sets whose contents are to be gathered */
                                      const int num_sets
                                      /**< number of sets in list */
)
{
    ErrorCode rval = MB_SUCCESS;
    if( !ent_sets || num_sets == 0 )
    {
        rval = mMB->get_entities_by_handle( 0, all_ents );
    }
    else
    {
        for( int i = 0; i < num_sets; i++ )
        {
            ErrorCode tmp_rval = mMB->get_entities_by_handle( ent_sets[i], all_ents );
            if( MB_SUCCESS != tmp_rval ) rval = tmp_rval;
        }
    }

    return rval;
}

ErrorCode WriteUtil::get_node_coords( const int num_arrays,
                                      const int num_nodes,
                                      const Range& entities,
                                      Tag node_id_tag,
                                      const int start_node_id,
                                      std::vector< double* >& arrays )
{
    // Check the data coming into the function
    // Dimension should be proper
    if( num_arrays < 1 || num_arrays > 3 ) return MB_FAILURE;

    // There should be some entities
    // if (entities.empty())
    //  return MB_FAILURE;
    // The above necessitates annoying special cases for files
    // w/out vertices (e.g. a kD-tree).  Return NULL array
    // pointers instead. - kraftcheck, 3-14-08
    if( entities.empty() )
    {
        arrays.clear();
        arrays.resize( num_arrays, NULL );
        return MB_SUCCESS;
    }

    // Memory should already be allocated for us
    int tmp_num_arrays = 0;
    for( unsigned int i = 0; i < 3; i++ )
        if( i + 1 <= arrays.size() && NULL != arrays[i] ) tmp_num_arrays++;
    if( 0 == tmp_num_arrays ) return MB_FAILURE;

    // Get coordinate data
    ErrorCode result = mMB->get_coords( entities, num_arrays < 1 || arrays.size() < 1 ? NULL : arrays[0],
                                        num_arrays < 2 || arrays.size() < 2 ? NULL : arrays[1],
                                        num_arrays < 3 || arrays.size() < 3 ? NULL : arrays[2] );

    if( 0 == node_id_tag || MB_SUCCESS != result ) return result;

    // Now assign tags
    std::vector< int > ids( num_nodes );
    int node_id = start_node_id;
    for( int i = 0; i < num_nodes; i++ )
        ids[i] = node_id++;
    result = mMB->tag_set_data( node_id_tag, entities, &ids[0] );

    return result;
}

ErrorCode WriteUtil::get_node_coords( const int which_array, /* 0->X, 1->Y, 2->Z, -1->all */
                                      Range::const_iterator iter,
                                      const Range::const_iterator& end,
                                      const size_t output_array_len,
                                      double* const output_array )
{
    // Check the data coming into the function
    // Dimension should be proper
    if( which_array < -1 || which_array > 2 ) return MB_FAILURE;

    // There should be some entities
    if( iter == end ) return MB_FAILURE;

    // Memory should already be allocated for us
    if( NULL == output_array || 0 == output_array_len ) return MB_FAILURE;

    // Sequence iterators
    TypeSequenceManager::iterator seq_iter, seq_end;
    seq_iter = mMB->sequence_manager()->entity_map( MBVERTEX ).begin();
    seq_end  = mMB->sequence_manager()->entity_map( MBVERTEX ).end();

    // Loop over range, getting coordinate value
    double* output_iter      = output_array;
    double* const output_end = output_array + output_array_len;
    while( iter != end )
    {
        // Find the sequence containing the current handle
        while( seq_iter != seq_end && ( *seq_iter )->end_handle() < *iter )
            ++seq_iter;
        if( seq_iter == seq_end || *iter < ( *seq_iter )->start_handle() ) return MB_FAILURE;

        // Determine how much of the sequence we want.
        Range::pair_iterator pair( iter );
        Range::const_iterator prev( end );
        --prev;
        EntityHandle range_end    = pair->second;
        EntityHandle sequence_end = ( *seq_iter )->end_handle();
        EntityHandle end_handle   = range_end > sequence_end ? sequence_end : range_end;
        if( end_handle > *prev ) end_handle = *prev;
        EntityHandle count = end_handle - *iter + 1;

        // Get offset in sequence to start at
        assert( *iter >= ( *seq_iter )->start_handle() );
        EntityHandle offset = *iter - ( *seq_iter )->start_handle();

        // Get coordinate arrays from sequence
        double* coord_array[3];
        static_cast< VertexSequence* >( *seq_iter )
            ->get_coordinate_arrays( coord_array[0], coord_array[1], coord_array[2] );

        // Copy data to output buffer
        if( -1 != which_array )
        {
            if( output_iter + count > output_end ) return MB_FAILURE;
            memcpy( output_iter, coord_array[which_array] + offset, count * sizeof( double ) );
            output_iter += count;
        }
        else
        {
            if( output_iter + 3 * count > output_end ) return MB_FAILURE;
            for( unsigned int i = 0; i < count; i++ )
            {
                *output_iter = coord_array[0][i + offset];
                output_iter++;
                *output_iter = coord_array[1][i + offset];
                output_iter++;
                *output_iter = coord_array[2][i + offset];
                output_iter++;
            }
        }

        // Iterate
        iter += count;
    }

    return MB_SUCCESS;
}

ErrorCode WriteUtil::get_element_connect( const int num_elements,
                                          const int verts_per_element,
                                          Tag node_id_tag,
                                          const Range& elements,
                                          Tag element_id_tag,
                                          int start_element_id,
                                          int* element_array,
                                          bool add_sizes )
{
    // Check the data we got
    if( num_elements < 1 ) return MB_FAILURE;
    if( verts_per_element < 1 ) return MB_FAILURE;
    if( elements.empty() ) return MB_FAILURE;
    if( !element_array ) return MB_FAILURE;

    Range::const_iterator range_iter     = elements.begin();
    Range::const_iterator range_iter_end = elements.end();

    TypeSequenceManager::iterator seq_iter, seq_iter_end;
    EntityType current_type = TYPE_FROM_HANDLE( *range_iter );

    seq_iter     = mMB->sequence_manager()->entity_map( current_type ).begin();
    seq_iter_end = mMB->sequence_manager()->entity_map( current_type ).end();

    // Let's find the entity sequence which holds the first entity
    TypeSequenceManager::iterator seq_iter_lookahead = seq_iter;
    ++seq_iter_lookahead;
    for( ; seq_iter_lookahead != seq_iter_end && ( *seq_iter_lookahead )->start_handle() < *range_iter; )
    {
        ++seq_iter;
        ++seq_iter_lookahead;
    }

    // A look ahead iterator
    Range::const_iterator range_iter_lookahead = range_iter;

    // Our main loop
    for( ; range_iter != range_iter_end && seq_iter != seq_iter_end; /* ++ is handled in loop*/ )
    {
        // Find a range that fits in the current entity sequence
        for( ; range_iter_lookahead != range_iter_end && *range_iter_lookahead <= ( *seq_iter )->end_handle();
             ++range_iter_lookahead )
        {
        }

        if( current_type != TYPE_FROM_HANDLE( *range_iter ) )
        {
            current_type = TYPE_FROM_HANDLE( *range_iter );
            seq_iter     = mMB->sequence_manager()->entity_map( current_type ).begin();
            seq_iter_end = mMB->sequence_manager()->entity_map( current_type ).end();

            // Let's find the entity sequence which holds the first entity of this type
            TypeSequenceManager::const_iterator seq_iter_lookahead2 = seq_iter;
            ++seq_iter_lookahead2;
            for( ; seq_iter_lookahead2 != seq_iter_end && ( *seq_iter_lookahead2 )->start_handle() < *range_iter; )
            {
                ++seq_iter;
                ++seq_iter_lookahead2;
            }
        }

        int i = static_cast< ElementSequence* >( *seq_iter )->nodes_per_element();

        // Get the connectivity array
        EntityHandle* conn_array = static_cast< ElementSequence* >( *seq_iter )->get_connectivity_array();

        EntityHandle start_handle = ( *seq_iter )->start_handle();

        for( Range::const_iterator tmp_iter = range_iter; tmp_iter != range_iter_lookahead; ++tmp_iter )
        {
            // Set the element id tag
            mMB->tag_set_data( element_id_tag, &*tmp_iter, 1, &start_element_id );
            ++start_element_id;

            if( add_sizes ) *element_array++ = i;

            // For each node
            for( int j = 0; j < i; j++ )
            {
                EntityHandle node = *( conn_array + j + i * ( *tmp_iter - start_handle ) );
                mMB->tag_get_data( node_id_tag, &node, 1, element_array );
                element_array++;
            }
        }

        // Go to the next entity sequence
        ++seq_iter;
        // Start with the next entities
        range_iter = range_iter_lookahead;
    }

    return MB_SUCCESS;
}

ErrorCode WriteUtil::get_element_connect( Range::const_iterator iter,
                                          const Range::const_iterator& end,
                                          const int vertices_per_elem,
                                          Tag node_id_tag,
                                          const size_t elem_array_size,
                                          int* const element_array,
                                          bool add_sizes )
{
    // Check the data we got
    if( iter == end ) return MB_FAILURE;
    if( vertices_per_elem < 1 ) return MB_FAILURE;
    if( !element_array || elem_array_size < (unsigned)vertices_per_elem ) return MB_FAILURE;

    // Sequence iterators
    TypeSequenceManager::const_iterator seq_iter, seq_end;

    // loop over range, getting coordinate value
    EntityType current_type = MBMAXTYPE;
    int* output_iter        = element_array;
    int* const output_end   = element_array + elem_array_size;
    while( iter != end )
    {
        // Make sure we have the right sequence list (and get the sequence
        // list for the first iteration.)
        EntityType type = TYPE_FROM_HANDLE( *iter );
        if( type != current_type )
        {
            if( type >= MBENTITYSET || type < MBEDGE ) return MB_FAILURE;
            seq_iter     = mMB->sequence_manager()->entity_map( type ).begin();
            seq_end      = mMB->sequence_manager()->entity_map( type ).end();
            current_type = type;
        }

        // Find the sequence containing the current handle
        while( seq_iter != seq_end && ( *seq_iter )->end_handle() < *iter )
            ++seq_iter;
        if( seq_iter == seq_end || *iter < ( *seq_iter )->start_handle() ) return MB_FAILURE;

        // Get the connectivity array
        EntityHandle* conn_array = NULL;
        int conn_size            = static_cast< ElementSequence* >( *seq_iter )->nodes_per_element();
        conn_array               = static_cast< ElementSequence* >( *seq_iter )->get_connectivity_array();

        // Determine how much of the sequence we want.
        Range::pair_iterator pair( iter );
        Range::const_iterator prev( end );
        --prev;
        EntityHandle range_end    = pair->second;
        EntityHandle sequence_end = ( *seq_iter )->end_handle();
        EntityHandle end_handle   = range_end > sequence_end ? sequence_end : range_end;
        if( end_handle > *prev ) end_handle = *prev;
        EntityHandle count = end_handle - *iter + 1;

        // Get offset in sequence to start at
        assert( *iter >= ( *seq_iter )->start_handle() );
        EntityHandle offset = *iter - ( *seq_iter )->start_handle();

        // Make sure sufficient space in output array
        if( ( !add_sizes && output_iter + ( count * conn_size ) > output_end ) ||
            ( add_sizes && output_iter + ( count * ( conn_size + 1 ) ) > output_end ) )
            return MB_FAILURE;

        // If the nodes per element match, do in one call
        conn_array += ( conn_size * offset );
        if( vertices_per_elem == conn_size && !add_sizes )
        {
            ErrorCode rval = mMB->tag_get_data( node_id_tag, conn_array, count * conn_size, output_iter );
            if( MB_SUCCESS != rval ) return rval;

            output_iter += count * conn_size;
        }
        // Otherwise need to do one at a time
        else
        {
            int min = vertices_per_elem > conn_size ? conn_size : vertices_per_elem;
            for( EntityHandle i = 0; i < count; ++i )
            {
                *output_iter++ = min;
                ErrorCode rval = mMB->tag_get_data( node_id_tag, conn_array, min, output_iter );
                if( MB_SUCCESS != rval ) return rval;

                output_iter += min;
                conn_array += conn_size;

                if( vertices_per_elem > conn_size )
                {  // Need to pad
                    memset( output_iter, 0, sizeof( int ) * ( vertices_per_elem - conn_size ) );
                    output_iter += ( vertices_per_elem - conn_size );
                }
            }
        }

        iter += count;
    }

    return MB_SUCCESS;
}

ErrorCode WriteUtil::get_element_connect( Range::const_iterator iter,
                                          const Range::const_iterator& end,
                                          const int vertices_per_elem,
                                          const size_t elem_array_size,
                                          EntityHandle* const element_array )
{
    // Check the data we got
    if( iter == end ) return MB_FAILURE;
    if( vertices_per_elem < 1 ) return MB_FAILURE;
    if( !element_array || elem_array_size < (unsigned)vertices_per_elem ) return MB_FAILURE;

    // Sequence iterators
    TypeSequenceManager::const_iterator seq_iter, seq_end;

    // Loop over range, getting coordinate value
    EntityType current_type        = MBMAXTYPE;
    EntityHandle* output_iter      = element_array;
    EntityHandle* const output_end = element_array + elem_array_size;
    while( iter != end )
    {
        // Make sure we have the right sequence list (and get the sequence
        // list for the first iteration.)
        EntityType type = TYPE_FROM_HANDLE( *iter );
        if( type != current_type )
        {
            if( type >= MBENTITYSET || type < MBEDGE ) return MB_FAILURE;
            seq_iter     = mMB->sequence_manager()->entity_map( type ).begin();
            seq_end      = mMB->sequence_manager()->entity_map( type ).end();
            current_type = type;
        }

        // Find the sequence containing the current handle
        while( seq_iter != seq_end && ( *seq_iter )->end_handle() < *iter )
            ++seq_iter;
        if( seq_iter == seq_end || *iter < ( *seq_iter )->start_handle() ) return MB_FAILURE;

        // Get the connectivity array
        EntityHandle* conn_array = NULL;
        int conn_size            = static_cast< ElementSequence* >( *seq_iter )->nodes_per_element();
        if( conn_size != vertices_per_elem ) return MB_FAILURE;
        conn_array = static_cast< ElementSequence* >( *seq_iter )->get_connectivity_array();

        // Determine how much of the sequence we want.
        Range::pair_iterator pair( iter );
        Range::const_iterator prev( end );
        --prev;
        EntityHandle range_end    = pair->second;
        EntityHandle sequence_end = ( *seq_iter )->end_handle();
        EntityHandle end_handle   = range_end > sequence_end ? sequence_end : range_end;
        if( end_handle > *prev ) end_handle = *prev;
        EntityHandle count = end_handle - *iter + 1;

        // Get offset in sequence to start at
        assert( *iter >= ( *seq_iter )->start_handle() );
        EntityHandle offset = *iter - ( *seq_iter )->start_handle();

        // Make sure sufficient space in output array
        if( output_iter + ( count * conn_size ) > output_end ) return MB_FAILURE;

        if( conn_array == NULL )
        {  // If it is structured mesh
            ErrorCode rval;
            int temp_buff_size = conn_size * sizeof( EntityHandle );
            for( unsigned i = 0; i < count; i++ )
            {  // Copy connectivity element by element
                std::vector< EntityHandle > connect;
                rval = static_cast< ElementSequence* >( *seq_iter )->get_connectivity( *iter, connect );
                if( MB_SUCCESS != rval )
                {
                    return rval;
                }
                memcpy( output_iter, &connect[0], temp_buff_size );
                output_iter += conn_size;
                ++iter;
            }
        }
        else
        {
            // Copy connectivity into output array
            conn_array += ( conn_size * offset );
            memcpy( output_iter, conn_array, count * conn_size * sizeof( EntityHandle ) );
            output_iter += count * conn_size;
            iter += count;
        }
    }

    return MB_SUCCESS;
}

ErrorCode WriteUtil::get_poly_connect_size( Range::const_iterator /* begin */,
                                            const Range::const_iterator& /* end */,
                                            int& /* connectivity_size */ )
{
    return MB_NOT_IMPLEMENTED;
}

ErrorCode WriteUtil::get_poly_connect( Range::const_iterator& /* iter */,
                                       const Range::const_iterator& /* end */,
                                       const Tag /* node_id_tag */,
                                       size_t& /* handle_array_len */,
                                       int* const /* handle_array */,
                                       size_t& /* index_array_len */,
                                       int* const /* index_array */,
                                       int& /* index_offset */ )
{
    return MB_NOT_IMPLEMENTED;
}

ErrorCode WriteUtil::gather_nodes_from_elements( const Range& elements, const Tag node_bit_mark_tag, Range& nodes )
{
    bool printed_warning = false;

    if( elements.empty() ) return MB_SUCCESS;

    if( TYPE_FROM_HANDLE( elements.front() ) <= MBVERTEX || TYPE_FROM_HANDLE( elements.back() ) >= MBENTITYSET )
        return MB_TYPE_OUT_OF_RANGE;

    // See if we need to use our own marking tag
    Tag exporting_nodes_tag = 0;
    if( node_bit_mark_tag )
        exporting_nodes_tag = node_bit_mark_tag;
    else
    {
        mMB->tag_get_handle( "__MBWriteUtil::exporting_nodes", 1, MB_TYPE_BIT, exporting_nodes_tag, MB_TAG_CREAT );
    }

    // The x,y,z tag handles we need
    EntityHandle lower_bound = ~0, upper_bound = 0;

    std::vector< EntityHandle > tmp_conn;

    RangeSeqIntersectIter iter( mMB->sequence_manager() );
    for( ErrorCode rval = iter.init( elements.begin(), elements.end() ); MB_FAILURE != rval; rval = iter.step() )
    {
        if( MB_ENTITY_NOT_FOUND == rval )
        {
            if( !printed_warning )
            {
                std::cerr << "Warning: ignoring invalid element handle(s) in gather_nodes_from_elements" << std::endl;
                printed_warning = true;
            }
            continue;
        }

        ElementSequence* seq = static_cast< ElementSequence* >( iter.get_sequence() );

        // Get the connectivity array
        const EntityHandle* conn_array = seq->get_connectivity_array();

        // If unstructured mesh
        if( conn_array && mMB->type_from_handle( iter.get_start_handle() ) != MBPOLYHEDRON )
        {
            assert( iter.get_start_handle() >= seq->start_handle() );
            assert( iter.get_end_handle() <= seq->end_handle() );
            const EntityHandle offset   = iter.get_start_handle() - seq->start_handle();
            const EntityHandle num_elem = iter.get_end_handle() - iter.get_start_handle() + 1;

            conn_array += offset * seq->nodes_per_element();
            const EntityHandle num_node = num_elem * seq->nodes_per_element();

            // For each node
            for( EntityHandle j = 0; j < num_node; j++ )
            {
                EntityHandle node = conn_array[j];
                if( node < lower_bound ) lower_bound = node;
                if( node > upper_bound ) upper_bound = node;
                unsigned char bit = 0x1;
                rval              = mMB->tag_set_data( exporting_nodes_tag, &node, 1, &bit );
                assert( MB_SUCCESS == rval );
                if( MB_SUCCESS != rval ) return rval;
            }
        }
        // Polyhedra
        else if( conn_array && mMB->type_from_handle( iter.get_start_handle() ) == MBPOLYHEDRON )
        {
            assert( iter.get_start_handle() >= seq->start_handle() );
            assert( iter.get_end_handle() <= seq->end_handle() );
            const EntityHandle offset   = iter.get_start_handle() - seq->start_handle();
            const EntityHandle num_elem = iter.get_end_handle() - iter.get_start_handle() + 1;

            conn_array += offset * seq->nodes_per_element();
            int num_face = num_elem * seq->nodes_per_element();

            // For each node
            for( int j = 0; j < num_face; j++ )
            {
                const EntityHandle* face_conn = NULL;
                int face_num_conn             = 0;
                rval                          = mMB->get_connectivity( conn_array[j], face_conn, face_num_conn, false );
                if( MB_SUCCESS != rval ) return rval;
                for( int k = 0; k < face_num_conn; k++ )
                {
                    EntityHandle node = face_conn[k];
                    if( node < lower_bound ) lower_bound = node;
                    if( node > upper_bound ) upper_bound = node;
                    unsigned char bit = 0x1;
                    rval              = mMB->tag_set_data( exporting_nodes_tag, &node, 1, &bit );
                    assert( MB_SUCCESS == rval );
                    if( MB_SUCCESS != rval ) return rval;
                }
            }
        }
        // Structured mesh
        else
        {
            EntityHandle end_h = iter.get_end_handle() + 1;
            for( EntityHandle h = iter.get_start_handle(); h < end_h; ++h )
            {
                tmp_conn.clear();
                rval = seq->get_connectivity( h, tmp_conn, false );
                if( MB_SUCCESS != rval )
                {
                    if( node_bit_mark_tag == 0 ) mMB->tag_delete( exporting_nodes_tag );
                    return rval;
                }

                // For each node
                for( size_t j = 0; j < tmp_conn.size(); j++ )
                {
                    EntityHandle node = tmp_conn[j];
                    if( node < lower_bound ) lower_bound = node;
                    if( node > upper_bound ) upper_bound = node;
                    unsigned char bit = 0x1;
                    mMB->tag_set_data( exporting_nodes_tag, &node, 1, &bit );
                }
            }
        }
    }

    // We can get a REALLY long loop if lower_bound is zero
    assert( lower_bound != 0 );
    // Gather up all the nodes
    for( ; upper_bound >= lower_bound; --upper_bound )
    {
        unsigned char node_marked = 0;
        mMB->tag_get_data( exporting_nodes_tag, &upper_bound, 1, &node_marked );
        if( node_marked == 0x1 ) nodes.insert( upper_bound );
    }

    // Clean up our own marking tag
    if( node_bit_mark_tag == 0 ) mMB->tag_delete( exporting_nodes_tag );

    return MB_SUCCESS;
}

//! Assign ids to input elements starting with start_id, written to id_tag
//! if zero, assigns to GLOBAL_ID_TAG_NAME
ErrorCode WriteUtil::assign_ids( Range& elements, Tag id_tag, const int start_id )
{
    ErrorCode result;
    if( 0 == id_tag )
    {
        // Get the global id tag
        id_tag = mMB->globalId_tag();
    }

    // Now assign the ids
    int i;
    Range::iterator rit;
    ErrorCode tmp_result;
    result = MB_SUCCESS;
    for( i = start_id, rit = elements.begin(); rit != elements.end(); ++rit, i++ )
    {
        tmp_result = mMB->tag_set_data( id_tag, &( *rit ), 1, &i );
        if( MB_SUCCESS != tmp_result ) result = tmp_result;
    }

    return result;
}

ErrorCode WriteUtil::get_adjacencies( EntityHandle entity, Tag id_tag, std::vector< int >& adj )
{
    ErrorCode rval;
    const EntityHandle* adj_array;
    int num_adj, id;

    // Get handles of adjacent entities
    rval = mMB->a_entity_factory()->get_adjacencies( entity, adj_array, num_adj );
    if( MB_SUCCESS != rval )
    {
        adj.clear();
        return rval;
    }

    // Append IDs of adjacent entities -- skip meshsets
    adj.resize( num_adj );  // Pre-allocate space
    adj.clear();            // Clear used space

    const EntityHandle* const end = adj_array + num_adj;
    for( const EntityHandle* iter = adj_array; iter != end; ++iter )
    {
        if( TYPE_FROM_HANDLE( *iter ) != MBENTITYSET )
        {
            rval = mMB->tag_get_data( id_tag, iter, 1, &id );
            if( MB_SUCCESS != rval ) return rval;
            adj.push_back( id );
        }
    }

    return MB_SUCCESS;
}

ErrorCode WriteUtil::get_adjacencies( EntityHandle entity, const EntityHandle*& adj_array, int& num_adj )
{
    return mMB->a_entity_factory()->get_adjacencies( entity, adj_array, num_adj );
}

ErrorCode WriteUtil::get_tag_list( std::vector< Tag >& result_list,
                                   const Tag* user_tag_list,
                                   int user_tag_list_length,
                                   bool include_variable_length_tags )
{
    ErrorCode rval;

    if( user_tag_list )
    {
        result_list.clear();
        result_list.reserve( user_tag_list_length );
        for( int i = 0; i < user_tag_list_length; ++i )
        {
            std::string name;
            rval = mMB->tag_get_name( user_tag_list[i], name );MB_CHK_SET_ERR( rval, "Error " << (int)rval << " getting name for tag (Invalid input tag handle?)" );

            if( name.empty() )
            {
                MB_SET_ERR( MB_TAG_NOT_FOUND, "Explicit request to save anonymous tag" );
            }

            int size;
            if( !include_variable_length_tags &&
                MB_VARIABLE_DATA_LENGTH == mMB->tag_get_length( user_tag_list[i], size ) )
            {
                MB_SET_ERR( MB_TYPE_OUT_OF_RANGE, "File format cannot store variable-length tag: \"" << name << "\"" );
            }

            result_list.push_back( user_tag_list[i] );
        }
    }
    else
    {
        std::vector< Tag > temp_list;
        rval = mMB->tag_get_tags( temp_list );MB_CHK_SET_ERR( rval, "Interface::tag_get_tags failed" );

        result_list.clear();
        result_list.reserve( temp_list.size() );

        std::vector< Tag >::iterator i;
        for( i = temp_list.begin(); i != temp_list.end(); ++i )
        {
            std::string name;
            rval = mMB->tag_get_name( *i, name );MB_CHK_SET_ERR( rval, "Error " << (int)rval << " getting name for tag (Stale tag handle?)" );

            // Skip anonymous tags
            if( name.empty() ) continue;

            // Skip private/internal tags
            if( name.size() >= 2 && name[0] == '_' && name[1] == '_' ) continue;

            // If requested, skip variable-length tags
            int size;
            if( !include_variable_length_tags && MB_VARIABLE_DATA_LENGTH == mMB->tag_get_length( *i, size ) ) continue;

            result_list.push_back( *i );
        }
    }

    return MB_SUCCESS;
}

ErrorCode WriteUtil::get_entity_list_pointers( Range::const_iterator begin,
                                               Range::const_iterator end,
                                               EntityHandle const** pointers,
                                               EntityListType relation,
                                               int* lengths,
                                               unsigned char* flags )
{
    RangeSeqIntersectIter iter( mMB->sequence_manager() );
    ErrorCode rval = iter.init( begin, end );
    while( MB_SUCCESS == rval )
    {
        EntityType type = TYPE_FROM_HANDLE( iter.get_start_handle() );

        if( MBENTITYSET == type )
        {
            const MeshSetSequence* seq = reinterpret_cast< MeshSetSequence* >( iter.get_sequence() );
            const MeshSet* set;
            int len = 0;
            size_t clen;
            for( EntityHandle h = iter.get_start_handle(); h <= iter.get_end_handle(); ++h )
            {
                set = seq->get_set( h );
                switch( relation )
                {
                    case CONTENTS:
                        *pointers = set->get_contents( clen );
                        len       = clen;
                        break;
                    case CHILDREN:
                        *pointers = set->get_children( len );
                        break;
                    case PARENTS:
                        *pointers = set->get_parents( len );
                        break;
                }
                if( lengths )
                {
                    *lengths = len;
                    ++lengths;
                }
                if( flags )
                {
                    *flags = (unsigned char)set->flags();
                    ++flags;
                }
                ++pointers;
            }
        }

        else if( MBVERTEX != type )
        {
            const bool topological = ( relation == TOPOLOGICAL );
            int len;
            const ElementSequence* seq = reinterpret_cast< ElementSequence* >( iter.get_sequence() );
            for( EntityHandle h = iter.get_start_handle(); h <= iter.get_end_handle(); ++h )
            {
                rval = seq->get_connectivity( h, *pointers, len, topological );
                if( MB_SUCCESS != rval ) return rval;
                if( lengths )
                {
                    *lengths = len;
                    ++lengths;
                }
                if( flags )
                {
                    *flags = 0;
                    ++flags;
                }
                ++pointers;
            }
        }
        else
        {
            return MB_TYPE_OUT_OF_RANGE;
        }

        rval = iter.step();
    }
    if( MB_FAILURE == rval )
        return MB_SUCCESS;  // At end of list
    else
        return rval;
}

ErrorCode WriteUtil::get_entity_list_pointers( EntityHandle const* entities,
                                               int num_entities,
                                               EntityHandle const** pointers,
                                               EntityListType relation,
                                               int* lengths,
                                               unsigned char* flags )
{
    SequenceManager* sm = mMB->sequence_manager();
    const EntitySequence* tmp_seq;
    ErrorCode rval = MB_SUCCESS;
    for( int i = 0; i < num_entities; i++ )
    {
        rval = sm->find( entities[i], tmp_seq );
        if( MB_SUCCESS != rval ) return rval;

        EntityType type = TYPE_FROM_HANDLE( entities[i] );

        if( MBENTITYSET == type )
        {
            const MeshSetSequence* seq = reinterpret_cast< const MeshSetSequence* >( tmp_seq );
            const MeshSet* set;
            int len = 0;
            size_t clen;
            set = seq->get_set( entities[i] );
            switch( relation )
            {
                case CONTENTS:
                    *pointers = set->get_contents( clen );
                    len       = clen;
                    break;
                case CHILDREN:
                    *pointers = set->get_children( len );
                    break;
                case PARENTS:
                    *pointers = set->get_parents( len );
                    break;
            }
            if( lengths )
            {
                *lengths = len;
                ++lengths;
            }
            if( flags )
            {
                *flags = (unsigned char)set->flags();
                ++flags;
            }
            ++pointers;
        }
        else if( MBVERTEX != type )
        {
            const bool topological = ( relation == TOPOLOGICAL );
            int len;
            const ElementSequence* seq = reinterpret_cast< const ElementSequence* >( tmp_seq );
            rval                       = seq->get_connectivity( entities[i], *pointers, len, topological );
            if( MB_SUCCESS != rval ) return rval;
            if( lengths )
            {
                *lengths = len;
                ++lengths;
            }
            if( flags )
            {
                *flags = 0;
                ++flags;
            }
            ++pointers;
        }
        else
        {
            return MB_TYPE_OUT_OF_RANGE;
        }
    }

    return MB_SUCCESS;
}

}  // namespace moab