Sequence.cc

// -*- mode: c++; c-basic-offset:4 -*-

// This file is part of libdap, A C++ implementation of the OPeNDAP Data
// Access Protocol.

// Copyright (c) 2002,2003 OPeNDAP, Inc.
// Author: James Gallagher <jgallagher@opendap.org>
//
// 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.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
//
// You can contact OPeNDAP, Inc. at PO Box 112, Saunderstown, RI. 02874-0112.

// (c) COPYRIGHT URI/MIT 1994-1999
// Please read the full copyright statement in the file COPYRIGHT_URI.
//
// Authors:
//      jhrg,jimg       James Gallagher <jgallagher@gso.uri.edu>

// Implementation for the class Structure
//
// jhrg 9/14/94

#include "config.h"

//#define DODS_DEBUG
//#define DODS_DEBUG2

#include <algorithm>
#include <string>
#include <sstream>

#include "Byte.h"
#include "Int16.h"
#include "UInt16.h"
#include "Int32.h"
#include "UInt32.h"
#include "Float32.h"
#include "Float64.h"
#include "Str.h"
#include "Url.h"
#include "Array.h"
#include "Structure.h"
#include "Sequence.h"
#include "Grid.h"

#include "Marshaller.h"
#include "UnMarshaller.h"

#include "debug.h"
#include "Error.h"
#include "InternalErr.h"
#include "Sequence.h"
#include "DDS.h"
#include "DataDDS.h"
#include "util.h"
#include "InternalErr.h"
#include "escaping.h"

#include "D4Attributes.h"
#include "D4Sequence.h"
#include "D4Group.h"
#include "Constructor.h"
#include "DMR.h"
#include "DapIndent.h"

#undef CLEAR_LOCAL_DATA

using namespace std;

namespace libdap {

static const unsigned char end_of_sequence = 0xA5; // binary pattern 1010 0101
static const unsigned char start_of_instance = 0x5A; // binary pattern 0101 1010

// Private member functions

void Sequence::m_duplicate(const Sequence &s)
{
    DBG(cerr << "In Sequence::m_duplicate" << endl);

    d_row_number = s.d_row_number;
    d_starting_row_number = s.d_starting_row_number;
    d_ending_row_number = s.d_ending_row_number;
    d_row_stride = s.d_row_stride;
    d_leaf_sequence = s.d_leaf_sequence;
    d_unsent_data = s.d_unsent_data;
    d_wrote_soi = s.d_wrote_soi;
    d_top_most = s.d_top_most;

    Sequence &cs = const_cast<Sequence &>(s);

    // Copy the BaseType objects used to hold values.
    for (vector<BaseTypeRow *>::iterator rows_iter = cs.d_values.begin(); rows_iter != cs.d_values.end(); rows_iter++) {
        // Get the current BaseType Row
        BaseTypeRow *src_bt_row_ptr = *rows_iter;
        // Create a new row.
        BaseTypeRow *dest_bt_row_ptr = new BaseTypeRow;
        // Copy the BaseType objects from a row to new BaseType objects.
        // Push new BaseType objects onto new row.
        for (BaseTypeRow::iterator bt_row_iter = src_bt_row_ptr->begin(); bt_row_iter != src_bt_row_ptr->end();
                bt_row_iter++) {
            BaseType *src_bt_ptr = *bt_row_iter;
            BaseType *dest_bt_ptr = src_bt_ptr->ptr_duplicate();
            dest_bt_row_ptr->push_back(dest_bt_ptr);
        }
        // Push new row onto d_values.
        d_values.push_back(dest_bt_row_ptr);
    }
}

static void write_end_of_sequence(Marshaller &m)
{
    m.put_opaque((char *) &end_of_sequence, 1);
}

static void write_start_of_instance(Marshaller &m)
{
    m.put_opaque((char *) &start_of_instance, 1);
}

static unsigned char read_marker(UnMarshaller &um)
{
    unsigned char marker;
    um.get_opaque((char *) &marker, 1);

    return marker;
}

static bool is_start_of_instance(unsigned char marker)
{
    return (marker == start_of_instance);
}

static bool is_end_of_sequence(unsigned char marker)
{
    return (marker == end_of_sequence);
}

// Public member functions

Sequence::Sequence(const string &n) :
        Constructor(n, dods_sequence_c), d_row_number(-1), d_starting_row_number(-1), d_row_stride(1), d_ending_row_number(
                -1), d_unsent_data(false), d_wrote_soi(false), d_leaf_sequence(false), d_top_most(false)
{
}

Sequence::Sequence(const string &n, const string &d) :
        Constructor(n, d, dods_sequence_c), d_row_number(-1), d_starting_row_number(-1),
        d_row_stride(1), d_ending_row_number(-1), d_unsent_data(false),
        d_wrote_soi(false), d_leaf_sequence(false), d_top_most(false)
{
}

Sequence::Sequence(const Sequence &rhs) :
        Constructor(rhs)
{
    m_duplicate(rhs);
}

BaseType *
Sequence::ptr_duplicate()
{
    return new Sequence(*this);
}

void
Sequence::transform_to_dap4(D4Group *root, Constructor *container)
{
    D4Sequence *dest;
    // If it's already a DAP4 object then we can just return it!
    if(is_dap4()){
        dest = static_cast<D4Sequence*>(ptr_duplicate());
        dest->set_length(-1);
        container->add_var_nocopy(dest);
        return;
    }
    dest = new D4Sequence(name());
    Constructor::transform_to_dap4(root, dest);
    dest->set_length(-1);
    container->add_var_nocopy(dest);
}

static inline void delete_bt(BaseType *bt_ptr)
{
    delete bt_ptr;
    bt_ptr = 0;
}

static inline void delete_rows(BaseTypeRow *bt_row_ptr)
{
    for_each(bt_row_ptr->begin(), bt_row_ptr->end(), delete_bt);

    delete bt_row_ptr;
    bt_row_ptr = 0;
}

Sequence::~Sequence()
{
    clear_local_data();
}

void Sequence::clear_local_data()
{
    if (!d_values.empty()) {
        for_each(d_values.begin(), d_values.end(), delete_rows);
        d_values.resize(0);
    }

    set_read_p(false);
}

Sequence &
Sequence::operator=(const Sequence &rhs)
{
    if (this == &rhs) return *this;

    dynamic_cast<Constructor &>(*this) = rhs; // run Constructor=

    m_duplicate(rhs);

    return *this;
}

bool Sequence::is_dap2_only_type()
{
    return true;
}

string Sequence::toString()
{
    ostringstream oss;

    oss << BaseType::toString();

    for (Vars_iter i = d_vars.begin(); i != d_vars.end(); i++) {
        oss << (*i)->toString();
    }

    oss << endl;

    return oss.str();
}

bool Sequence::is_linear()
{
    bool linear = true;
    bool seq_found = false;
    for (Vars_iter iter = d_vars.begin(); linear && iter != d_vars.end(); iter++) {
        if ((*iter)->type() == dods_sequence_c) {
            // A linear sequence cannot have more than one child seq. at any
            // one level. If we've already found a seq at this level, return
            // false.
            if (seq_found) {
                linear = false;
                break;
            }
            seq_found = true;
            linear = static_cast<Sequence *>((*iter))->is_linear();
        }
        else if ((*iter)->type() == dods_structure_c) {
            linear = static_cast<Structure*>((*iter))->is_linear();
        }
        else {
            // A linear sequence cannot have Arrays, Lists or Grids.
            linear = (*iter)->is_simple_type();
        }
    }

    return linear;
}

BaseTypeRow *
Sequence::row_value(size_t row)
{
    if (row >= d_values.size()) return 0;   //nullptr
    return d_values[row];
}

void Sequence::set_value(SequenceValues &values)
{
    d_values = values;
}

SequenceValues Sequence::value()
{
    return d_values;
}

SequenceValues &
Sequence::value_ref()
{
    return d_values;
}

BaseType *
Sequence::var_value(size_t row, const string &name)
{
    BaseTypeRow *bt_row_ptr = row_value(row);
    if (!bt_row_ptr) return 0;

    BaseTypeRow::iterator bt_row_iter = bt_row_ptr->begin();
    BaseTypeRow::iterator bt_row_end = bt_row_ptr->end();
    while (bt_row_iter != bt_row_end && (*bt_row_iter)->name() != name)
        ++bt_row_iter;

    if (bt_row_iter == bt_row_end)
        return 0;
    else
        return *bt_row_iter;
}

BaseType *
Sequence::var_value(size_t row, size_t i)
{
    BaseTypeRow *bt_row_ptr = row_value(row);
    if (!bt_row_ptr) return 0;

    if (i >= bt_row_ptr->size()) return 0;

    return (*bt_row_ptr)[i];
}

// This version returns -1. Each API-specific subclass should define a more
// reasonable version. jhrg 5/24/96

int Sequence::length() const
{
    return -1;
}

// Hmmm. how is this different from length()?
int Sequence::number_of_rows() const
{
    return d_values.size();
}

void Sequence::reset_row_number()
{
    d_row_number = -1;
}

void Sequence::reset_row_number(bool recur)
{
    reset_row_number();

    if (recur)
        for (Vars_iter i = var_begin(), e = var_end(); i != e; ++i)
            if ((*i)->type() == dods_sequence_c)
                reset_row_number(true);
}

// Notes:
// Assume that read() is implemented so that, when reading data for a nested
// sequence, only the outer most level is *actually* read.
// This is a consequence of our current (12/7/99) implementation of
// the JGOFS server (which is the only server to actually use nested
// sequences). 12/7/99 jhrg
//
// Stop assuming this. This logic is being moved into the JGOFS server
// itself. 6/1/2001 jhrg

// The read() function returns a boolean value, with TRUE
// indicating that read() should be called again because there's
// more data to read, and FALSE indicating there's no more data
// to read. Note that this behavior is necessary to properly
// handle variables that contain Sequences. Jose Garcia If an
// error exists while reading, the implementers of the surrogate
// library SHOULD throw an Error object which will propagate
// beyond this point to to the original caller.
// Jose Garcia

bool Sequence::read_row(int row, DDS &dds, ConstraintEvaluator &eval, bool ce_eval)
{
    DBG2(cerr << "Entering Sequence::read_row for " << name() << ", row number " << row << ", current row " << d_row_number << endl);
    if (row < d_row_number) throw InternalErr("Trying to back up inside a sequence!");

    if (row == d_row_number) {
        DBG2(cerr << "Leaving Sequence::read_row for " << name() << endl);
        return false;
    }

    bool eof = false;  // Start out assuming EOF is false.
    while (!eof && d_row_number < row) {
        if (!read_p()) {
            // jhrg original version from 10/9/13 : eof = (read() == false);
            eof = read();
        }

        // Advance the row number if ce_eval is false (we're not supposed to
        // evaluate the selection) or both ce_eval and the selection are
        // true.
        if (!eof && (!ce_eval || eval.eval_selection(dds, dataset()))) d_row_number++;

        set_read_p(false); // ...so that the next instance will be read
    }

    // Once we finish the above loop, set read_p to true so that the caller
    // knows that data *has* been read. This is how the read() methods of the
    // elements of the sequence know to not call read() but instead look for
    // data values inside themselves.
    set_read_p(true);

    // Return true if we have valid data, false if we've read to the EOF.
    DBG2(cerr << "Leaving Sequence::read_row for " << name() << " with eof: " << eof << endl);
    return !eof; // jhrg 10/10/13 was: eof == 0;
}

// Private. This is used to process constraints on the rows of a sequence.
// Starting with 3.2 we support constraints like Sequence[10:2:20]. This
// odd-looking logic first checks if d_ending_row_number is the sentinel
// value of -1. If so, the sequence was not constrained by row number and
// this method should never return true (which indicates that we're at the
// end of a row-number constraint). If d_ending_row_number is not -1, then is
// \e i at the end point? 6/1/2001 jhrg
inline bool Sequence::is_end_of_rows(int i)
{
    return ((d_ending_row_number == -1) ? false : (i > d_ending_row_number));
}

bool Sequence::serialize(ConstraintEvaluator &eval, DDS &dds, Marshaller &m, bool ce_eval)
{
    // Special case leaf sequences!
    bool status = false;

    if (is_leaf_sequence())
        status = serialize_leaf(dds, eval, m, ce_eval);
    else
        status = serialize_parent_part_one(dds, eval, m);

    return status;
}

// We know this is not a leaf Sequence. That means that this Sequence holds
// another Sequence as one of its fields _and_ that child Sequence triggers
// the actual transmission of values.

bool Sequence::serialize_parent_part_one(DDS &dds, ConstraintEvaluator &eval, Marshaller &m)
{
    DBG2(cerr << "Entering serialize_parent_part_one for " << name() << endl);

    int i = (d_starting_row_number != -1) ? d_starting_row_number : 0;

    // read_row returns true if valid data was read, false if the EOF was
    // found. 6/1/2001 jhrg
    // Since this is a parent sequence, read the row ignoring the CE (all of
    // the CE clauses will be evaluated by the leaf sequence).
    bool status = read_row(i, dds, eval, false);
    DBG2(cerr << "Sequence::serialize_parent_part_one::read_row() status: " << status << endl);

    while (status && !is_end_of_rows(i)) {
        i += d_row_stride;

        // DBG(cerr << "Writing Start of Instance marker" << endl);
        // write_start_of_instance(sink);

        // In this loop serialize will signal an error with an exception.
        for (Vars_iter iter = d_vars.begin(); iter != d_vars.end(); iter++) {
            // Only call serialize for child Sequences; the leaf sequence
            // will trigger the transmission of values for its parents (this
            // sequence and maybe others) once it gets some valid data to
            // send.
            // Note that if the leaf sequence has no variables in the current
            // projection, its serialize() method will never be called and that's
            // the method that triggers actually sending values. Thus the leaf
            // sequence must be the lowest level sequence with values whose send_p
            // property is true.
            if ((*iter)->send_p() && (*iter)->type() == dods_sequence_c) (*iter)->serialize(eval, dds, m);
        }

        set_read_p(false); // ...so this will read the next instance

        status = read_row(i, dds, eval, false);
        DBG(cerr << "Sequence::serialize_parent_part_one::read_row() status: " << status << endl);
    }
    // Reset current row number for next nested sequence element.
    d_row_number = -1;

    // Always write the EOS marker? 12/23/04 jhrg
    // Yes. According to DAP2, a completely empty response is signaled by
    // a return value of only the EOS marker for the outermost sequence.
    if (d_top_most || d_wrote_soi) {
        DBG(cerr << "Writing End of Sequence marker" << endl);
        write_end_of_sequence(m);
        d_wrote_soi = false;
    }

    return true;  // Signal errors with exceptions.
}

// If we are here then we know that this is 'parent sequence' and that the
// leaf sequence has found valid data to send. We also know that
// serialize_parent_part_one has been called so data are in the instance's
// fields. This is where we send data. Whereas ..._part_one() contains a
// loop to iterate over all of rows in a parent sequence, this does not. This
// method assumes that the serialize_leaf() will call it each time it needs
// to be called.
//
// NB: This code only works if the child sequences appear after all other
// variables.
void Sequence::serialize_parent_part_two(DDS &dds, ConstraintEvaluator &eval, Marshaller &m)
{
    DBG(cerr << "Entering serialize_parent_part_two for " << name() << endl);

    BaseType *btp = get_parent();
    if (btp && btp->type() == dods_sequence_c) static_cast<Sequence&>(*btp).serialize_parent_part_two(dds, eval, m);

    if (d_unsent_data) {
        DBG(cerr << "Writing Start of Instance marker" << endl);
        d_wrote_soi = true;
        write_start_of_instance(m);

        // In this loop serialize will signal an error with an exception.
        for (Vars_iter iter = d_vars.begin(); iter != d_vars.end(); iter++) {
            // Send all the non-sequence variables
            DBG(cerr << "Sequence::serialize_parent_part_two(), serializing "
                    << (*iter)->name() << endl);
            if ((*iter)->send_p() && (*iter)->type() != dods_sequence_c) {
                DBG(cerr << "Send P is true, sending " << (*iter)->name() << endl);
                (*iter)->serialize(eval, dds, m, false);
            }
        }

        d_unsent_data = false;              // read should set this.
    }
}

// This code is only run by a leaf sequence. Note that a one level sequence
// is also a leaf sequence.
bool Sequence::serialize_leaf(DDS &dds, ConstraintEvaluator &eval, Marshaller &m, bool ce_eval)
{
    DBG(cerr << "Entering Sequence::serialize_leaf for " << name() << endl);
    int i = (d_starting_row_number != -1) ? d_starting_row_number : 0;

    // read_row returns true if valid data was read, false if the EOF was
    // found. 6/1/2001 jhrg
    bool status = read_row(i, dds, eval, ce_eval);
    DBG(cerr << "Sequence::serialize_leaf::read_row() status: " << status << endl);

    // Once the first valid (satisfies the CE) row of the leaf sequence has
    // been read, we know we're going to send data. Send the current instance
    // of the parent/ancestor sequences now, if there are any. We only need
    // to do this once, hence it's not inside the while loop, but we only
    // send the parent seq data _if_ there's data in the leaf to send, that's
    // why we wait until after the first call to read_row() here in the leaf
    // sequence.
    //
    // NB: It's important to only call serialize_parent_part_two() for a
    // Sequence that really is the parent of a leaf sequence.
    if (status && !is_end_of_rows(i)) {
        BaseType *btp = get_parent();
        if (btp && btp->type() == dods_sequence_c) static_cast<Sequence&>(*btp).serialize_parent_part_two(dds, eval, m);
    }

    d_wrote_soi = false;
    while (status && !is_end_of_rows(i)) {
        i += d_row_stride;

        DBG(cerr << "Writing Start of Instance marker" << endl);
        d_wrote_soi = true;
        write_start_of_instance(m);

        // In this loop serialize will signal an error with an exception.
        for (Vars_iter iter = d_vars.begin(); iter != d_vars.end(); iter++) {
            DBG(cerr << "Sequence::serialize_leaf(), serializing "
                    << (*iter)->name() << endl);
            if ((*iter)->send_p()) {
                DBG(cerr << "Send P is true, sending " << (*iter)->name() << endl);
                (*iter)->serialize(eval, dds, m, false);
            }
        }

        set_read_p(false); // ...so this will read the next instance

        status = read_row(i, dds, eval, ce_eval);
        DBG(cerr << "Sequence::serialize_leaf::read_row() status: " << status << endl);
    }

    // Only write the EOS marker if there's a matching Start Of Instance
    // Marker in the stream.
    if (d_wrote_soi || d_top_most) {
        DBG(cerr << "Writing End of Sequence marker" << endl);
        write_end_of_sequence(m);
    }

    return true;  // Signal errors with exceptions.
}

void Sequence::intern_data(ConstraintEvaluator &eval, DDS &dds)
{
    DBG(cerr << "Sequence::intern_data - for " << name() << endl); DBG2(cerr << "    intern_data, values: " << &d_values << endl);

    // Why use a stack instead of return values? We need the stack because
    // Sequences nested three of more levels deep will loose the middle
    // instances when the intern_data_parent_part_two() code is run.
    sequence_values_stack_t sequence_values_stack;

    sequence_values_stack.push(&d_values);

    intern_data_private(eval, dds, sequence_values_stack);
}

void Sequence::intern_data_private(ConstraintEvaluator &eval, DDS &dds, sequence_values_stack_t &sequence_values_stack)
{
    DBG(cerr << "Entering intern_data_private for " << name() << endl);

    if (is_leaf_sequence())
        intern_data_for_leaf(dds, eval, sequence_values_stack);
    else
        intern_data_parent_part_one(dds, eval, sequence_values_stack);
}

void Sequence::intern_data_parent_part_one(DDS & dds, ConstraintEvaluator & eval,
        sequence_values_stack_t & sequence_values_stack)
{
    DBG(cerr << "Entering intern_data_parent_part_one for " << name() << endl);

    int i = (get_starting_row_number() != -1) ? get_starting_row_number() : 0;

    // read_row returns true if valid data was read, false if the EOF was
    // found. 6/1/2001 jhrg
    // Since this is a parent sequence, read the row ignoring the CE (all of
    // the CE clauses will be evaluated by the leaf sequence).
    bool status = read_row(i, dds, eval, false);

    // Grab the current size of the value stack. We do this because it is
    // possible that no nested sequences for this row happened to be
    // selected because of a constraint evaluation or the last row is not
    // selected because of a constraint evaluation. In either case, no
    // nested sequence d_values are pushed onto the stack, so there is
    // nothing to pop at the end of this function. pcw 07/14/08
    SequenceValues::size_type orig_stack_size = sequence_values_stack.size();

    while (status && (get_ending_row_number() == -1 || i <= get_ending_row_number())) {
        i += get_row_stride();
        for (Vars_iter iter = var_begin(); iter != var_end(); iter++) {
            if ((*iter)->send_p()) {
                switch ((*iter)->type()) {
                case dods_sequence_c:
                    static_cast<Sequence&>(**iter).intern_data_private(eval, dds, sequence_values_stack);
                    break;

                default:
                    (*iter)->intern_data(eval, dds);
                    break;
                }
            }
        }

        set_read_p(false);      // ...so this will read the next instance

        status = read_row(i, dds, eval, false);
    }

    // Reset current row number for next nested sequence element.
    reset_row_number();

    // if the size of the stack is larger than the original size (retrieved
    // above) then pop the top set of d_values from the stack. If it's the
    // same, then no nested sequences, or possibly the last nested sequence,
    // were pushed onto the stack, so there is nothing to pop.
    if (sequence_values_stack.size() > orig_stack_size) {
        DBG2(cerr << "    popping d_values (" << sequence_values_stack.top()
                << ") off stack; size: " << sequence_values_stack.size() << endl);
        sequence_values_stack.pop();
    }

    DBG(cerr << "Leaving intern_data_parent_part_one for " << name() << endl);
}

void Sequence::intern_data_parent_part_two(DDS &dds, ConstraintEvaluator &eval,
        sequence_values_stack_t &sequence_values_stack)
{
    DBG(cerr << "Entering intern_data_parent_part_two for " << name() << endl);

    BaseType *btp = get_parent();
    if (btp && btp->type() == dods_sequence_c) {
        static_cast<Sequence&>(*btp).intern_data_parent_part_two(dds, eval, sequence_values_stack);
    }

    DBG2(cerr << "    stack size: " << sequence_values_stack.size() << endl);
    SequenceValues *values = sequence_values_stack.top();
    DBG2(cerr << "    using values = " << (void *)values << endl);

    if (get_unsent_data()) {
        BaseTypeRow *row_data = new BaseTypeRow;

        // In this loop transfer_data will signal an error with an exception.
        for (Vars_iter iter = var_begin(); iter != var_end(); iter++) {

            if ((*iter)->send_p() && (*iter)->type() != dods_sequence_c) {
                row_data->push_back((*iter)->ptr_duplicate());
            }
            else if ((*iter)->send_p()) { //Sequence; must be the last variable
                Sequence *tmp = dynamic_cast<Sequence*>((*iter)->ptr_duplicate());
                if (!tmp) {
                    delete row_data;
                    throw InternalErr(__FILE__, __LINE__, "Expected a Sequence.");
                }
                row_data->push_back(tmp);
                DBG2(cerr << "    pushing d_values of " << tmp->name()
                        << " (" << &(tmp->d_values)
                        << ") on stack; size: " << sequence_values_stack.size()
                        << endl);
                // This pushes the d_values field of the newly created leaf
                // Sequence onto the stack. The code then returns to intern
                // _data_for_leaf() where this value will be used.
                sequence_values_stack.push(&(tmp->d_values));
            }
        }

        DBG2(cerr << "    pushing values for " << name()
                << " to " << values << endl);
        values->push_back(row_data);
        set_unsent_data(false);
    }

    DBG(cerr << "Leaving intern_data_parent_part_two for " << name() << endl);
}

void Sequence::intern_data_for_leaf(DDS &dds, ConstraintEvaluator &eval, sequence_values_stack_t &sequence_values_stack)
{
    DBG(cerr << "Entering intern_data_for_leaf for " << name() << endl);

    int i = (get_starting_row_number() != -1) ? get_starting_row_number() : 0;

    DBG2(cerr << "    reading row " << i << endl);
    bool status = read_row(i, dds, eval, true);
    DBG2(cerr << "    status: " << status << endl); DBG2(cerr << "    ending row number: " << get_ending_row_number() << endl);

    if (status && (get_ending_row_number() == -1 || i <= get_ending_row_number())) {
        BaseType *btp = get_parent();
        if (btp && btp->type() == dods_sequence_c) {
            // This call will read the values for the parent sequences and
            // then allocate a new instance for the leaf and push that onto
            // the stack.
            static_cast<Sequence&>(*btp).intern_data_parent_part_two(dds, eval, sequence_values_stack);
        }

        // intern_data_parent_part_two pushes the d_values field of the leaf
        // onto the stack, so this operation grabs that value and then loads
        // data into it.
        SequenceValues *values = sequence_values_stack.top();
        DBG2(cerr << "    using values = " << values << endl);

        while (status && (get_ending_row_number() == -1 || i <= get_ending_row_number())) {
            i += get_row_stride();

            // Copy data from the object's fields to this new BaeTypeRow instance
            BaseTypeRow *row_data = new BaseTypeRow;
            for (Vars_iter iter = var_begin(); iter != var_end(); iter++) {
                if ((*iter)->send_p()) {
                    row_data->push_back((*iter)->ptr_duplicate());
                }
            }

            DBG2(cerr << "    pushing values for " << name()
                    << " to " << values << endl);
            // Save the row_data to values().
            values->push_back(row_data);

            set_read_p(false);      // ...so this will read the next instance
            // Read the ith row into this object's fields
            status = read_row(i, dds, eval, true);
        }

        DBG2(cerr << "    popping d_values (" << sequence_values_stack.top()
                << ") off stack; size: " << sequence_values_stack.size() << endl);
        sequence_values_stack.pop();
    }

    DBG(cerr << "Leaving intern_data_for_leaf for " << name() << endl);
}

bool Sequence::deserialize(UnMarshaller &um, DDS *dds, bool reuse)
{
#if 0
    // Nathan's tip - this is something that should never happen
    DataDDS *dd = dynamic_cast<DataDDS *>(dds);
    if (!dd) throw InternalErr("Expected argument 'dds' to be a DataDDS!");

    DBG2(cerr << "Reading from server/protocol version: "
            << dd->get_protocol_major() << "." << dd->get_protocol_minor()
            << endl);

    // Check for old servers.
    if (dd->get_protocol_major() < 2) {
        throw Error(
                string("The protocl version (") + dd->get_protocol()
                        + ") indicates that this\nis an old server which may not correctly transmit Sequence variables.\nContact the server administrator.");
    }
#endif
    while (true) {
        // Grab the sequence stream's marker.
        unsigned char marker = read_marker(um);
        if (is_end_of_sequence(marker))
            break;  // EXIT the while loop here!!!
        else if (is_start_of_instance(marker)) {
            d_row_number++;
            DBG2(cerr << "Reading row " << d_row_number << " of "
                    << name() << endl);
            BaseTypeRow *bt_row_ptr = new BaseTypeRow;
            // Read the instance's values, building up the row
            for (Vars_iter iter = d_vars.begin(); iter != d_vars.end(); iter++) {
                BaseType *bt_ptr = (*iter)->ptr_duplicate();
                bt_ptr->deserialize(um, dds, reuse);
                DBG2(cerr << "Deserialized " << bt_ptr->name() << " ("
                        << bt_ptr << ") = "); DBG2(bt_ptr->print_val(stderr, ""));
                bt_row_ptr->push_back(bt_ptr);
            }
            // Append this row to those accumulated.
            d_values.push_back(bt_row_ptr);
        }
        else
            throw Error("I could not read the expected Sequence data stream marker!");
    };

    return false;
}

// Return the current row number.

int Sequence::get_starting_row_number()
{
    return d_starting_row_number;
}

int Sequence::get_row_stride()
{
    return d_row_stride;
}

int Sequence::get_ending_row_number()
{
    return d_ending_row_number;
}

void Sequence::set_row_number_constraint(int start, int stop, int stride)
{
    if (stop < start) throw Error(malformed_expr, "Starting row number must precede the ending row number.");

    d_starting_row_number = start;
    d_row_stride = stride;
    d_ending_row_number = stop;
}

void Sequence::print_one_row(FILE *out, int row, string space, bool print_row_num)
{
    ostringstream oss;
    print_one_row(oss, row, space, print_row_num);
    fwrite(oss.str().data(), sizeof(char), oss.str().length(), out);
}

void Sequence::print_one_row(ostream &out, int row, string space, bool print_row_num)
{
    if (print_row_num) out << "\n" << space << row << ": ";

    out << "{ ";

    int elements = element_count();
    int j = 0;
    BaseType *bt_ptr = 0;

    // This version of print_one_row() works for both data read with
    // deserialize(), where each variable is assumed to have valid data, and
    // intern_data(), where some/many variables do not. Because of that, it's
    // not correct to assume that all of the elements will be printed, which
    // is what the old code did.
    // Print the first value
    while (j < elements && !bt_ptr) {
        bt_ptr = var_value(row, j++);
        if (bt_ptr) {  // data
            if (bt_ptr->type() == dods_sequence_c)
                static_cast<Sequence*>(bt_ptr)->print_val_by_rows(out, space + "    ", false, print_row_num);
            else
                bt_ptr->print_val(out, space, false);
        }
    }

    // Print the remaining values
    while (j < elements) {
        bt_ptr = var_value(row, j++);
        if (bt_ptr) {  // data
            out << ", ";
            if (bt_ptr->type() == dods_sequence_c)
                static_cast<Sequence*>(bt_ptr)->print_val_by_rows(out, space + "    ", false, print_row_num);
            else
                bt_ptr->print_val(out, space, false);
        }
    }

    out << " }";
}

void Sequence::print_val_by_rows(FILE *out, string space, bool print_decl_p, bool print_row_numbers)
{
    ostringstream oss;
    print_val_by_rows(oss, space, print_decl_p, print_row_numbers);
    fwrite(oss.str().data(), sizeof(char), oss.str().length(), out);
}

void Sequence::print_val_by_rows(ostream &out, string space, bool print_decl_p, bool print_row_numbers)
{
    if (print_decl_p) {
        print_decl(out, space, false);
        out << " = ";
    }

    out << "{ ";

    int rows = number_of_rows() - 1;
    int i;
    for (i = 0; i < rows; ++i) {
        print_one_row(out, i, space, print_row_numbers);
        out << ", ";
    }
    print_one_row(out, i, space, print_row_numbers);

    out << " }";

    if (print_decl_p) out << ";\n";
}

void Sequence::print_val(FILE *out, string space, bool print_decl_p)
{
    print_val_by_rows(out, space, print_decl_p, false);
}

void Sequence::print_val(ostream &out, string space, bool print_decl_p)
{
    print_val_by_rows(out, space, print_decl_p, false);
}

void Sequence::set_leaf_p(bool state)
{
    d_leaf_sequence = state;
}

bool Sequence::is_leaf_sequence()
{
    return d_leaf_sequence;
}

void Sequence::set_leaf_sequence(int lvl)
{
    bool has_child_sequence = false;

    if (lvl == 1) d_top_most = true;

    DBG2(cerr << "Processing sequence " << name() << endl);

    for (Vars_iter iter = d_vars.begin(); iter != d_vars.end(); iter++) {
        // About the test for send_p(): Only descend into a sequence if it has
        // fields that might be sent. Thus if, in a two-level sequence, nothing
        // in the lower level is to be sent, the upper level is marked as the
        // leaf sequence. This ensures that values _will_ be sent (see the comment
        // in serialize_leaf() and serialize_parent_part_one()).
        if ((*iter)->type() == dods_sequence_c && (*iter)->send_p()) {
            if (has_child_sequence)
                throw Error("This implementation does not support more than one nested sequence at a level. Contact the server administrator.");

            has_child_sequence = true;
            static_cast<Sequence&>(**iter).set_leaf_sequence(++lvl);
        }
        else if ((*iter)->type() == dods_structure_c) {
            static_cast<Structure&>(**iter).set_leaf_sequence(lvl);
        }
    }

    if (!has_child_sequence)
        set_leaf_p(true);
    else
        set_leaf_p(false);

    DBG2(cerr << "is_leaf_sequence(): " << is_leaf_sequence() << " (" << name() << ")" << endl);
}

void Sequence::dump(ostream &strm) const
{
    strm << DapIndent::LMarg << "Sequence::dump - (" << (void *) this << ")" << endl;
    DapIndent::Indent();
    Constructor::dump(strm);
    strm << DapIndent::LMarg << "# rows deserialized: " << d_row_number << endl;
    strm << DapIndent::LMarg << "bracket notation information:" << endl;
    DapIndent::Indent();
    strm << DapIndent::LMarg << "starting row #: " << d_starting_row_number << endl;
    strm << DapIndent::LMarg << "row stride: " << d_row_stride << endl;
    strm << DapIndent::LMarg << "ending row #: " << d_ending_row_number << endl;
    DapIndent::UnIndent();

    strm << DapIndent::LMarg << "data been sent? " << d_unsent_data << endl;
    strm << DapIndent::LMarg << "start of instance? " << d_wrote_soi << endl;
    strm << DapIndent::LMarg << "is leaf sequence? " << d_leaf_sequence << endl;
    strm << DapIndent::LMarg << "top most in hierarchy? " << d_top_most << endl;
    DapIndent::UnIndent();
}

} // namespace libdap