D4StreamUnMarshaller.cc

// D4StreamUnMarshaller.cc

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

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

// Copyright (c) 2012 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//
// You can contact OPeNDAP, Inc. at PO Box 112, Saunderstown, RI. 02874-0112.

#include "config.h"

#include <byteswap.h>
#include <cassert>

#include <iomanip>
#include <iostream>
#include <limits>
#include <sstream>
#include <string>

// #define DODS_DEBUG2 1
// #define DODS_DEBUG 1

#include "D4StreamUnMarshaller.h"
#include "DapIndent.h"
#include "InternalErr.h"
#include "debug.h"
#include "util.h"

namespace libdap {

/**
 * @brief Build a DAP4 Stream unMarshaller.
 *
 * Build a DAP4 Stream UnMarshaller initialed to read from am istream object.
 * Figure out if the words read for values need to be 'twiddled' based on the
 * byte-order of the stream an this host (see set_twiddle_bytes()).
 *
 * @param in Read from this input stream
 * @param is_stream_bigendian The byte order of the data in the stream
 */
D4StreamUnMarshaller::D4StreamUnMarshaller(istream &in, bool twiddle_bytes) : d_in(in), d_twiddle_bytes(twiddle_bytes) {
    assert(sizeof(std::streamsize) >= sizeof(int64_t));

#if USE_XDR_FOR_IEEE754_ENCODING
    // XDR is used to handle transforming non-ieee754 reals, nothing else.
    xdrmem_create(&d_source, d_buf, sizeof(dods_float64), XDR_DECODE);
#endif

    // This will cause exceptions to be thrown on i/o errors. The exception
    // will be ostream::failure
    d_in.exceptions(istream::failbit | istream::badbit);
}

/**
 * When using this constructor, set_twiddle_bytes() should be called
 * before data are processed.
 *
 * @param in
 */
D4StreamUnMarshaller::D4StreamUnMarshaller(istream &in) : d_in(in), d_twiddle_bytes(false) {
    assert(sizeof(std::streamsize) >= sizeof(int64_t));

#if USE_XDR_FOR_IEEE754_ENCODING
    // XDR is used to handle transforming non-ieee754 reals, nothing else.
    xdrmem_create(&d_source, d_buf, sizeof(dods_float64), XDR_DECODE);
#endif

    // This will cause exceptions to be thrown on i/o errors. The exception
    // will be ostream::failure
    d_in.exceptions(istream::failbit | istream::badbit);
}

D4StreamUnMarshaller::~D4StreamUnMarshaller() {
#if USE_XDR_FOR_IEEE754_ENCODING
    xdr_destroy(&d_source);
#endif
}

Crc32::checksum D4StreamUnMarshaller::get_checksum() {
    Crc32::checksum c;
    d_in.read(reinterpret_cast<char *>(&c), sizeof(Crc32::checksum));

    return c;
}

string D4StreamUnMarshaller::get_checksum_str() {
    ostringstream oss;
    oss.setf(ios::hex, ios::basefield);
    oss << setfill('0') << setw(8) << get_checksum();

    return oss.str();
}

void D4StreamUnMarshaller::get_byte(dods_byte &val) { d_in.read(reinterpret_cast<char *>(&val), sizeof(dods_byte)); }

void D4StreamUnMarshaller::get_int8(dods_int8 &val) { d_in.read(reinterpret_cast<char *>(&val), sizeof(dods_int8)); }

void D4StreamUnMarshaller::get_int16(dods_int16 &val) {
    d_in.read(reinterpret_cast<char *>(&val), sizeof(dods_int16));
    if (d_twiddle_bytes)
        val = bswap_16(val);
}

void D4StreamUnMarshaller::get_int32(dods_int32 &val) {
    d_in.read(reinterpret_cast<char *>(&val), sizeof(dods_int32));
    if (d_twiddle_bytes)
        val = bswap_32(val);
}

void D4StreamUnMarshaller::get_int64(dods_int64 &val) {
    d_in.read(reinterpret_cast<char *>(&val), sizeof(dods_int64));
    if (d_twiddle_bytes)
        val = bswap_64(val);
}

void D4StreamUnMarshaller::get_float32(dods_float32 &val) {
#if !USE_XDR_FOR_IEEE754_ENCODING
    assert(std::numeric_limits<float>::is_iec559);

    d_in.read(reinterpret_cast<char *>(&val), sizeof(dods_float32));
    if (d_twiddle_bytes) {
        dods_int32 *i = reinterpret_cast<dods_int32 *>(&val);
        *i = bswap_32(*i);
    }

#else
    if (std::numeric_limits<float>::is_iec559) {
        d_in.read(reinterpret_cast<char *>(&val), sizeof(dods_float32));
        if (d_twiddle_bytes) {
            dods_int32 *i = reinterpret_cast<dods_int32 *>(&val);
            *i = bswap_32(*i);
        }

    } else {
        xdr_setpos(&d_source, 0);
        d_in.read(d_buf, sizeof(dods_float32));

        if (!xdr_float(&d_source, &val))
            throw Error("Network I/O Error. Could not read float 64 data.");
    }
#endif
}

void D4StreamUnMarshaller::get_float64(dods_float64 &val) {
#if !USE_XDR_FOR_IEEE754_ENCODING
    assert(std::numeric_limits<double>::is_iec559);

    d_in.read(reinterpret_cast<char *>(&val), sizeof(dods_float64));
    if (d_twiddle_bytes) {
        dods_int64 *i = reinterpret_cast<dods_int64 *>(&val);
        *i = bswap_64(*i);
    }

#else
    if (std::numeric_limits<float>::is_iec559) {
        d_in.read(reinterpret_cast<char *>(&val), sizeof(dods_float64));
        if (d_twiddle_bytes) {
            dods_int64 *i = reinterpret_cast<dods_int64 *>(&val);
            *i = bswap_64(*i);
        }
    } else {
        xdr_setpos(&d_source, 0);
        d_in.read(d_buf, sizeof(dods_float64));

        if (!xdr_double(&d_source, &val))
            throw Error("Network I/O Error. Could not read float 64 data.");
    }
#endif
}

void D4StreamUnMarshaller::get_uint16(dods_uint16 &val) {
    d_in.read(reinterpret_cast<char *>(&val), sizeof(dods_uint16));
    if (d_twiddle_bytes)
        val = bswap_16(val);
}

void D4StreamUnMarshaller::get_uint32(dods_uint32 &val) {
    d_in.read(reinterpret_cast<char *>(&val), sizeof(dods_uint32));
    if (d_twiddle_bytes)
        val = bswap_32(val);
}

void D4StreamUnMarshaller::get_uint64(dods_uint64 &val) {
    d_in.read(reinterpret_cast<char *>(&val), sizeof(dods_uint64));
    if (d_twiddle_bytes)
        val = bswap_64(val);
}

void D4StreamUnMarshaller::get_str(string &val) {
    int64_t len;
    d_in.read(reinterpret_cast<char *>(&len), sizeof(int64_t));

    val.resize(len);
    d_in.read(&val[0], len);
}

void D4StreamUnMarshaller::get_url(string &val) { get_str(val); }

/**
 * Read a count value from the stream. This is used with D4Sequence
 * which needs to use various other 'get' methods to read its fields.
 * Methods like get_opaque_dap4() handle reading their count values
 * themselves.
 *
 * @param count The number of elements to follow.
 */
int64_t D4StreamUnMarshaller::get_count() {
    int64_t count;
    d_in.read(reinterpret_cast<char *>(&count), sizeof(count));
    return count;
}

/**
 * Get opaque data when the size of the data to be read is not known in
 * advance.
 *
 * @param val Value-result parameter for the data; caller must delete.
 * @param len value-result parameter for the length of the data
 */
void D4StreamUnMarshaller::get_opaque_dap4(char **val, int64_t &len) {
    // len = get_length_prefix();
    d_in.read(reinterpret_cast<char *>(&len), sizeof(len));

    *val = new char[len];
    d_in.read(*val, len);
}

void D4StreamUnMarshaller::get_opaque_dap4(vector<uint8_t> &val) {
    // len = get_length_prefix();
    int64_t len;
    d_in.read(reinterpret_cast<char *>(&len), sizeof(len));

    val.resize(len);
    d_in.read(reinterpret_cast<char *>(val.data()), len);
}

void D4StreamUnMarshaller::get_vector(char *val, int64_t bytes) { d_in.read(val, bytes); }

#if USE_XDR_FOR_IEEE754_ENCODING
void D4StreamUnMarshaller::m_deserialize_reals(char *val, int64_t num, int width, Type type) {
    int64_t size = num * width;
    // char *buf = (char*)malloc(size); jhrg 7/23/13
    vector<char> buf(size);
    XDR xdr;
    xdrmem_create(&xdr, buf.data(), size, XDR_DECODE);
    try {
        xdr_setpos(&d_source, 0);
        d_in.read(buf.data(), size);

        if (!xdr_array(&xdr, &val, (unsigned int *)&num, size, width, XDRUtils::xdr_coder(type)))
            throw InternalErr(__FILE__, __LINE__, "Error deserializing a Float64 array");

        if (xdr_getpos(&xdr) != size)
            throw InternalErr(__FILE__, __LINE__, "Error deserializing a Float64 array");
    } catch (...) {
        xdr_destroy(&xdr);
        throw;
    }
    xdr_destroy(&xdr);
}
#endif

void D4StreamUnMarshaller::m_twidle_vector_elements(char *vals, int64_t num, int width) {
    switch (width) {
    case 2: {
        dods_int16 *local = reinterpret_cast<dods_int16 *>(vals);
        while (num--) {
            *local = bswap_16(*local);
            local++;
        }
        break;
    }
    case 4: {
        dods_int32 *local = reinterpret_cast<dods_int32 *>(vals);
        ;
        while (num--) {
            *local = bswap_32(*local);
            local++;
        }
        break;
    }
    case 8: {
        dods_int64 *local = reinterpret_cast<dods_int64 *>(vals);
        ;
        while (num--) {
            *local = bswap_64(*local);
            local++;
        }
        break;
    }
    default:
        throw InternalErr(__FILE__, __LINE__, "Unrecognized word size.");
    }
}

void D4StreamUnMarshaller::get_vector(char *val, int64_t num_elem, int elem_size) {
    assert(std::numeric_limits<float>::is_iec559);
    assert(std::numeric_limits<double>::is_iec559);
    assert(val);
    assert(num_elem >= 0);
    assert(elem_size > 0);

    int64_t bytes;

    switch (elem_size) {
    case 1:
        assert(!"Don't call this method for bytes, use put_vector(val, bytes) instead");
        bytes = num_elem;
        break;
    case 2:
        // Don't bother testing the sign bit
        assert(!(num_elem & 0x4000000000000000)); // 0x 40 00 --> 0100 0000
        bytes = num_elem << 1;
        break;
    case 4:
        assert(!(num_elem & 0x6000000000000000)); // 0x 60 00 --> 0110 0000
        bytes = num_elem << 2;
        break;
    case 8:
        assert(!(num_elem & 0x7000000000000000)); // 0111 0000
        bytes = num_elem << 3;
        break;
    default:
        bytes = num_elem * elem_size;
        break;
    }

    d_in.read(val, bytes);

    if (d_twiddle_bytes)
        m_twidle_vector_elements(val, num_elem, elem_size);
}

void D4StreamUnMarshaller::get_vector_float32(char *val, int64_t num_elem) {
#if !USE_XDR_FOR_IEEE754_ENCODING
    assert(std::numeric_limits<float>::is_iec559);
    assert(val);
    assert(num_elem >= 0);
    assert(!(num_elem & 0x6000000000000000)); // 0x 60 00 --> 0110 0000

    int64_t bytes = num_elem << 2;

    d_in.read(val, bytes);

    if (d_twiddle_bytes)
        m_twidle_vector_elements(val, num_elem, sizeof(dods_float32));

#else
    if (type == dods_float32_c && !std::numeric_limits<float>::is_iec559) {
        // If not using IEEE 754, use XDR to get it that way.
        m_deserialize_reals(val, num, 4, type);
    } else if (type == dods_float64_c && !std::numeric_limits<double>::is_iec559) {
        m_deserialize_reals(val, num, 8, type);
    } else {
        d_in.read(val, num * width);
        if (d_twiddle_bytes)
            m_twidle_vector_elements(val, num, width);
    }
#endif
}

void D4StreamUnMarshaller::get_vector_float64(char *val, int64_t num_elem) {
#if !USE_XDR_FOR_IEEE754_ENCODING
    assert(std::numeric_limits<float>::is_iec559);
    assert(val);
    assert(num_elem >= 0);
    assert(!(num_elem & 0x7000000000000000)); // 0x 70 00 --> 0111 0000

    int64_t bytes = num_elem << 3;

    d_in.read(val, bytes);

    if (d_twiddle_bytes)
        m_twidle_vector_elements(val, num_elem, sizeof(dods_float64));

#else
    if (type == dods_float32_c && !std::numeric_limits<float>::is_iec559) {
        // If not using IEEE 754, use XDR to get it that way.
        m_deserialize_reals(val, num, 4, type);
    } else if (type == dods_float64_c && !std::numeric_limits<double>::is_iec559) {
        m_deserialize_reals(val, num, 8, type);
    } else {
        d_in.read(val, num * width);
        if (d_twiddle_bytes)
            m_twidle_vector_elements(val, num, width);
    }
#endif
}

void D4StreamUnMarshaller::dump(ostream &strm) const {
    strm << DapIndent::LMarg << "D4StreamUnMarshaller::dump - (" << (void *)this << ")" << endl;
}

} // namespace libdap