codec.cpp

// Copyright 2009-2023:
//   GobySoft, LLC (2013-)
//   Massachusetts Institute of Technology (2007-2014)
//   Community contributors (see AUTHORS file)
// File authors:
//   Toby Schneider <toby@gobysoft.org>
//   philboske <philboske@gmail.com>
//   Denis <dbiryukov@slb.com>
//   Nathan Knotts <nknotts@gmail.com>
//   Chris Murphy <cmurphy@aphysci.com>
//
//
// This file is part of the Dynamic Compact Control Language Library
// ("DCCL").
//
// DCCL 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.
//
// DCCL 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 DCCL.  If not, see <http://www.gnu.org/licenses/>.
#include <algorithm>
#include <utility>
 
#include <dlfcn.h> // for shared library loading
 
#include "codec.h"
 
#if DCCL_HAS_CRYPTOPP
#if CRYPTOPP_PATH_USES_PLUS_SIGN
#include <crypto++/aes.h>
#include <crypto++/filters.h>
#include <crypto++/modes.h>
#include <crypto++/sha.h>
#else
#include <cryptopp/aes.h>
#include <cryptopp/filters.h>
#include <cryptopp/modes.h>
#include <cryptopp/sha.h>
#endif // CRYPTOPP_PATH_USES_PLUS_SIGN
#endif // HAS_CRYPTOPP
 
#include "codecs3/field_codec_var_bytes.h"
#include "codecs4/field_codec_crc.h"
#include "codecs4/field_codec_hash.h"
#include "codecs4/field_codec_var_bytes.h"
#include "codecs5/field_codec_hash.h"
#include "codecs5/field_codec_var_bytes.h"
#include "field_codec_id.h"
 
#include "codecs2/default_field_codec_impl.h"
#include "codecs3/default_field_codec_impl.h"
#include "codecs4/default_field_codec_impl.h"
#include "codecs5/default_field_codec_impl.h"
 
using dccl::hex_encode;
 
using namespace dccl;
using namespace dccl::logger;
 
using google::protobuf::Descriptor;
using google::protobuf::FieldDescriptor;
using google::protobuf::Reflection;
 
//
// Codec
//
 
dccl::Codec::Codec(std::string dccl_id_codec_name, const std::string& library_path)
    : id_codec_(std::move(dccl_id_codec_name))
{
    set_default_codecs();
    manager_.add<DefaultIdentifierCodec>(default_id_codec_name());
 
    if (!library_path.empty())
        load_library(library_path);
    // make sure the id codec exists
    id_codec();
}
 
dccl::Codec::~Codec()
{
    for (auto& dl_handle : dl_handles_)
    {
        unload_library(dl_handle);
        dlclose(dl_handle);
    }
}
 
void dccl::Codec::set_default_codecs()
{
    using google::protobuf::FieldDescriptor;
 
    //
    // version 2
    //
    internal::DefaultFieldCodecLoader<2>::add(manager_);
    internal::TimeCodecLoader<2>::add(manager_);
    internal::StaticCodecLoader<2>::add(manager_);
 
    // backwards compatibility names (deprecated)
    internal::TimeCodecLoader<2>::add(manager_, "_time");
    internal::StaticCodecLoader<2>::add(manager_, "_static");
 
    //
    // version 3
    //
    internal::DefaultFieldCodecLoader<3>::add(manager_);
    internal::TimeCodecLoader<3>::add(manager_);
    internal::StaticCodecLoader<3>::add(manager_);
    internal::PresenceCodecLoader<3>::add(manager_);
    internal::VarBytesCodecLoader<3>::add(manager_);
 
    //
    // version 4
    //
    internal::DefaultFieldCodecLoader<4>::add(manager_);
    internal::TimeCodecLoader<4>::add(manager_);
    internal::StaticCodecLoader<4>::add(manager_);
    internal::PresenceCodecLoader<4>::add(manager_);
    internal::VarBytesCodecLoader<4>::add(manager_);
    internal::HashCodecLoader<4>::add(manager_, {2, 3, 4}); // backport for older versions 2 and 3
    internal::CRCCodecLoader<4>::add(manager_, {2, 3, 4}); // backport for older versions 2 and 3
 
    //
    // version 5
    //
    internal::DefaultFieldCodecLoader<5>::add(manager_);
    internal::TimeCodecLoader<5>::add(manager_);
    internal::StaticCodecLoader<5>::add(manager_);
    internal::PresenceCodecLoader<5>::add(manager_);
    internal::VarBytesCodecLoader<5>::add(manager_);
    internal::HashCodecLoader<5>::add(manager_);
    internal::CRCCodecLoader<5>::add(manager_);
}
 
void dccl::Codec::encode_internal(const google::protobuf::Message& msg, bool header_only,
                                  Bitset& head_bits, Bitset& body_bits, int user_id)
{
    const Descriptor* desc = msg.GetDescriptor();
 
    dlog.is(DEBUG1, ENCODE) && dlog << "Began encoding message of type: " << desc->full_name()
                                    << std::endl;
 
    try
    {
        int32 dccl_id = id_internal(desc, user_id);
        size_t head_byte_size = 0;
 
        if (!msg.IsInitialized() && !header_only)
        {
            std::stringstream ss;
 
            ss << "Message is not properly initialized. All `required` fields must be set. Fields "
                  "with errors: \n"
               << get_all_error_fields_in_message(msg);
 
            throw(Exception(ss.str(), desc));
        }
 
        if (!id2desc_.count(dccl_id))
            throw(Exception("Message id " + std::to_string(dccl_id) +
                            " has not been loaded. Call load() before encoding this type."),
                  desc);
 
        std::shared_ptr<FieldCodecBase> codec = manager_.find(desc);
        std::shared_ptr<internal::FromProtoCppTypeBase> helper = manager_.type_helper().find(desc);
 
        if (codec)
        {
            //fixed header
            if (!desc->options().GetExtension(dccl::msg).omit_id())
                id_codec()->field_encode(&head_bits, static_cast<uint32>(dccl_id), nullptr);
 
            internal::MessageStack msg_stack(manager_.codec_data().root_message_,
                                             manager_.codec_data().message_data_);
            msg_stack.push(msg.GetDescriptor());
            codec->base_encode(&head_bits, msg, HEAD, strict_);
 
            // given header of not even byte size (e.g. 01011), make even byte size (e.g. 00001011)
            head_byte_size = ceil_bits2bytes(head_bits.size());
            head_bits.resize(head_byte_size * BITS_IN_BYTE);
 
            if (header_only)
            {
                dlog.is(DEBUG2, ENCODE) &&
                    dlog << "as requested, skipping encoding and encrypting body." << std::endl;
            }
            else
            {
                codec->base_encode(&body_bits, msg, BODY, strict_);
            }
 
            // check dynamic max_bytes if configured
            const auto& msg_opt = desc->options().GetExtension(dccl::msg);
            if (msg_opt.has_dynamic_conditions() &&
                msg_opt.dynamic_conditions().has_max_bytes())
            {
                DynamicConditions dc;
                dc.set_descriptor(desc);
                dc.regenerate(&msg, &msg);
                const unsigned actual_size =
                    ceil_bits2bytes(head_bits.size()) + ceil_bits2bytes(body_bits.size());
                const uint32_t allowed_max = dc.max_bytes();
                if (actual_size > allowed_max)
                    throw(Exception(
                        "Encoded message size (" + std::to_string(actual_size) +
                            "B) exceeds dynamic max_bytes limit (" +
                            std::to_string(allowed_max) +
                            "B). Adjust message contents or increase the dynamic max_bytes limit.",
                        desc));
            }
        }
        else
        {
            throw(Exception("Failed to find (dccl.msg).codec `" +
                            desc->options().GetExtension(dccl::msg).codec() + "`"),
                  desc);
        }
    }
    catch (dccl::OutOfRangeException& e)
    {
        dlog.is(DEBUG1, ENCODE) &&
            dlog << "Message " << desc->full_name()
                 << " failed to encode because a field was out of bounds and strict == true: "
                 << e.what() << std::endl;
        throw;
    }
    catch (std::exception& e)
    {
        std::stringstream ss;
 
        ss << "Message " << desc->full_name() << " failed to encode. Reason: " << e.what();
 
        dlog.is(DEBUG1, ENCODE) && dlog << ss.str() << std::endl;
        throw(Exception(ss.str(), desc));
    }
}
 
size_t dccl::Codec::encode(char* bytes, size_t max_len, const google::protobuf::Message& msg,
                           bool header_only /* = false */, int user_id /* = -1 */)
{
    const Descriptor* desc = msg.GetDescriptor();
    Bitset head_bits;
    Bitset body_bits;
    encode_internal(msg, header_only, head_bits, body_bits, user_id);
 
    size_t head_byte_size = ceil_bits2bytes(head_bits.size());
    if (max_len < head_byte_size)
    {
        throw std::length_error("max_len must be >= head_byte_size");
    }
    head_bits.to_byte_string(bytes, head_byte_size);
 
    dlog.is(DEBUG2, ENCODE) && dlog << "Head bytes (bits): " << head_byte_size << "("
                                    << head_bits.size() << ")" << std::endl;
    dlog.is(DEBUG3, ENCODE) && dlog << "Unencrypted Head (bin): " << head_bits << std::endl;
    dlog.is(DEBUG3, ENCODE) && dlog << "Unencrypted Head (hex): "
                                    << hex_encode(bytes, bytes + head_byte_size) << std::endl;
 
    size_t body_byte_size = 0;
    if (!header_only)
    {
        body_byte_size = ceil_bits2bytes(body_bits.size());
        if (max_len < (head_byte_size + body_byte_size))
        {
            throw std::length_error("max_len must be >= (head_byte_size + body_byte_size)");
        }
        body_bits.to_byte_string(bytes + head_byte_size, max_len - head_byte_size);
 
        dlog.is(DEBUG3, ENCODE) && dlog << "Unencrypted Body (bin): " << body_bits << std::endl;
        dlog.is(DEBUG3, ENCODE) &&
            dlog << "Unencrypted Body (hex): "
                 << hex_encode(bytes + head_byte_size, bytes + head_byte_size + body_byte_size)
                 << std::endl;
        dlog.is(DEBUG2, ENCODE) && dlog << "Body bytes (bits): " << body_byte_size << "("
                                        << body_bits.size() << ")" << std::endl;
 
        int32 dccl_id = id_internal(desc, user_id);
        if (!crypto_key_.empty() && !skip_crypto_ids_.count(dccl_id))
        {
            std::string head_bytes(bytes, bytes + head_byte_size);
            std::string body_bytes(bytes + head_byte_size, bytes + head_byte_size + body_byte_size);
            encrypt(&body_bytes, head_bytes);
            std::memcpy(bytes + head_byte_size, body_bytes.data(), body_bytes.size());
        }
 
        dlog.is(logger::DEBUG3, logger::ENCODE) &&
            dlog << "Encrypted Body (hex): "
                 << hex_encode(bytes + head_byte_size, bytes + head_byte_size + body_byte_size)
                 << std::endl;
    }
 
    dlog.is(DEBUG1, ENCODE) && dlog << "Successfully encoded message of type: " << desc->full_name()
                                    << std::endl;
 
    return head_byte_size + body_byte_size;
}
 
void dccl::Codec::encode(std::string* bytes, const google::protobuf::Message& msg,
                         bool header_only /* = false */, int user_id /* = -1 */)
{
    const Descriptor* desc = msg.GetDescriptor();
    Bitset head_bits;
    Bitset body_bits;
    encode_internal(msg, header_only, head_bits, body_bits, user_id);
 
    std::string head_bytes = head_bits.to_byte_string();
 
    dlog.is(DEBUG2, ENCODE) && dlog << "Head bytes (bits): " << head_bytes.size() << "("
                                    << head_bits.size() << ")" << std::endl;
    dlog.is(DEBUG3, ENCODE) && dlog << "Unencrypted Head (bin): " << head_bits << std::endl;
    dlog.is(DEBUG3, ENCODE) && dlog << "Unencrypted Head (hex): " << hex_encode(head_bytes)
                                    << std::endl;
 
    std::string body_bytes;
    if (!header_only)
    {
        body_bytes = body_bits.to_byte_string();
 
        dlog.is(DEBUG3, ENCODE) && dlog << "Unencrypted Body (bin): " << body_bits << std::endl;
        dlog.is(DEBUG3, ENCODE) && dlog << "Unencrypted Body (hex): " << hex_encode(body_bytes)
                                        << std::endl;
        dlog.is(DEBUG2, ENCODE) && dlog << "Body bytes (bits): " << body_bytes.size() << "("
                                        << body_bits.size() << ")" << std::endl;
 
        int32 dccl_id = id_internal(desc, user_id);
        if (!crypto_key_.empty() && !skip_crypto_ids_.count(dccl_id))
            encrypt(&body_bytes, head_bytes);
 
        dlog.is(logger::DEBUG3, logger::ENCODE) &&
            dlog << "Encrypted Body (hex): " << hex_encode(body_bytes) << std::endl;
    }
 
    dlog.is(DEBUG1, ENCODE) && dlog << "Successfully encoded message of type: " << desc->full_name()
                                    << std::endl;
    *bytes += head_bytes + body_bytes;
}
 
int32 dccl::Codec::id(const std::string& bytes) const { return id(bytes.begin(), bytes.end()); }
 
// makes sure we can actual encode / decode a message of this descriptor given the loaded FieldCodecs
// checks all bounds on the message
std::size_t dccl::Codec::load(const google::protobuf::Descriptor* desc, int user_id /* = -1 */)
{
    try
    {
        const auto& msg_opt = desc->options().GetExtension(dccl::msg);
        if (user_id < 0 && !msg_opt.has_id() && !msg_opt.omit_id())
            throw(
                Exception("Missing message option `(dccl.msg).id`. Specify a unique id (e.g. 3) in "
                          "the body of your .proto message using \"option (dccl.msg).id = 3\"",
                          desc));
        if (!msg_opt.has_max_bytes())
            throw(Exception("Missing message option `(dccl.msg).max_bytes`. Specify a maximum "
                            "(encoded) message size in bytes (e.g. 32) in the body of your .proto "
                            "message using \"option (dccl.msg).max_bytes = 32\"",
                            desc));
 
        if (!msg_opt.has_codec_version())
            throw(Exception(
                "No (dccl.msg).codec_version set for DCCL Message '" +
                    std::string(desc->full_name()) +
                    "'. For new messages, set 'option (dccl.msg).codec_version = 4' in the "
                    "message definition for " +
                    std::string(desc->full_name()) + " to use the default DCCL4 codecs.",
                desc));
 
        std::shared_ptr<FieldCodecBase> codec = manager_.find(desc);
 
        int32 dccl_id = id_internal(desc, user_id);
 
        unsigned head_size_bits, body_size_bits;
        codec->base_max_size(&head_size_bits, desc, HEAD);
        codec->base_max_size(&body_size_bits, desc, BODY);
 
        unsigned id_bits = 0;
        if (!msg_opt.omit_id())
            id_codec()->field_size(&id_bits, static_cast<uint32>(dccl_id), nullptr);
        head_size_bits += id_bits;
 
        const unsigned byte_size =
            ceil_bits2bytes(head_size_bits) + ceil_bits2bytes(body_size_bits);
 
        auto actual_max = byte_size;
        auto allowed_max = msg_opt.max_bytes();
        if (actual_max > allowed_max)
            throw(Exception("Actual maximum size of message (" + std::to_string(actual_max) +
                                "B) exceeds allowed maximum (" + std::to_string(allowed_max) +
                                "B). Tighten "
                                "bounds, remove fields, improve codecs, or increase the allowed "
                                "value in (dccl.msg).max_bytes",
                            desc));
 
        codec->base_validate(desc, HEAD);
        codec->base_validate(desc, BODY);
 
        if (id2desc_.count(dccl_id) && desc != id2desc_.find(dccl_id)->second)
        {
            std::stringstream ss;
            ss << "`dccl id` " << dccl_id << " is already in use by Message "
               << id2desc_.find(dccl_id)->second->full_name() << ": "
               << id2desc_.find(dccl_id)->second;
 
            throw(Exception(ss.str(), desc));
        }
        else
        {
            id2desc_.emplace(dccl_id, desc);
        }
 
        dlog.is(DEBUG1) && dlog << "Successfully validated message of type: " << desc->full_name()
                                << std::endl;
 
        std::size_t hash_value = 0;
        codec->base_hash(&hash_value, desc, HEAD);
        codec->base_hash(&hash_value, desc, BODY);
        manager_.set_hash(desc, hash_value);
        return hash_value;
    }
    catch (Exception& e)
    {
        try
        {
            info(desc, &dlog);
        }
        catch (Exception& e)
        {
        }
 
        dlog.is(DEBUG1) && dlog << "Message " << desc->full_name() << ": " << desc
                                << " failed validation. Reason: " << e.what() << "\n"
                                << "If possible, information about the Message are printed above. "
                                << std::endl;
 
        throw;
    }
}
 
void dccl::Codec::unload(const google::protobuf::Descriptor* desc)
{
    unsigned int erased = 0;
    for (auto it = id2desc_.begin(); it != id2desc_.end();)
    {
        if (it->second == desc)
        {
            erased++;
            id2desc_.erase(it++);
        }
        else
        {
            it++;
        }
    }
    if (erased == 0)
    {
        dlog.is(DEBUG1) && dlog << "Message " << desc->full_name()
                                << ": is not loaded. Ignoring unload request." << std::endl;
    }
}
 
void dccl::Codec::unload(size_t dccl_id)
{
    if (id2desc_.count(dccl_id))
    {
        id2desc_.erase(dccl_id);
    }
    else
    {
        dlog.is(DEBUG1) && dlog << "Message with id " << dccl_id
                                << ": is not loaded. Ignoring unload request." << std::endl;
        return;
    }
}
 
unsigned dccl::Codec::size(const google::protobuf::Message& msg, int user_id /* = -1 */)
{
    const Descriptor* desc = msg.GetDescriptor();
 
    std::shared_ptr<FieldCodecBase> codec = manager_.find(desc);
 
    int32 dccl_id = id_internal(desc, user_id);
    unsigned head_size_bits;
    codec->base_size(&head_size_bits, msg, HEAD);
 
    unsigned id_bits = 0;
    if (!desc->options().GetExtension(dccl::msg).omit_id())
        id_codec()->field_size(&id_bits, static_cast<uint32>(dccl_id), nullptr);
    head_size_bits += id_bits;
 
    unsigned body_size_bits;
    codec->base_size(&body_size_bits, msg, BODY);
 
    const unsigned head_size_bytes = ceil_bits2bytes(head_size_bits);
    const unsigned body_size_bytes = ceil_bits2bytes(body_size_bits);
    return head_size_bytes + body_size_bytes;
}
 
unsigned dccl::Codec::max_size(const google::protobuf::Descriptor* desc, int user_id) const
{
    std::shared_ptr<FieldCodecBase> codec = manager_.find(desc);
 
    unsigned head_size_bits;
    codec->base_max_size(&head_size_bits, desc, HEAD);
 
    int32 dccl_id = id_internal_const(desc, user_id);
 
    unsigned id_bits = 0;
    if (!desc->options().GetExtension(dccl::msg).omit_id())
        id_codec()->field_size(&id_bits, static_cast<uint32>(dccl_id), nullptr);
    head_size_bits += id_bits;
 
    unsigned body_size_bits;
    codec->base_max_size(&body_size_bits, desc, BODY);
 
    const unsigned head_size_bytes = ceil_bits2bytes(head_size_bits);
    const unsigned body_size_bytes = ceil_bits2bytes(body_size_bits);
    return head_size_bytes + body_size_bytes;
}
 
unsigned dccl::Codec::min_size(const google::protobuf::Descriptor* desc, int user_id) const
{
    std::shared_ptr<FieldCodecBase> codec = manager_.find(desc);
 
    unsigned head_size_bits;
    codec->base_min_size(&head_size_bits, desc, HEAD);
 
    int32 dccl_id = id_internal_const(desc, user_id);
 
    unsigned id_bits = 0;
    if (!desc->options().GetExtension(dccl::msg).omit_id())
        id_codec()->field_size(&id_bits, static_cast<uint32>(dccl_id), nullptr);
    head_size_bits += id_bits;
 
    unsigned body_size_bits;
    codec->base_min_size(&body_size_bits, desc, BODY);
 
    const unsigned head_size_bytes = ceil_bits2bytes(head_size_bits);
    const unsigned body_size_bytes = ceil_bits2bytes(body_size_bits);
    return head_size_bytes + body_size_bytes;
}
 
void dccl::Codec::info(const google::protobuf::Descriptor* desc, std::ostream* param_os /*= 0 */,
                       int user_id /* = -1 */) const
{
    bool is_dlog = false;
    if (!param_os || param_os == &dlog)
        is_dlog = true;
    std::stringstream ss;
    std::ostream* os = (is_dlog) ? &ss : param_os;
 
    if (!is_dlog || dlog.check(INFO))
    {
        try
        {
            bool omit_id = desc->options().GetExtension(dccl::msg).omit_id();
 
            std::shared_ptr<FieldCodecBase> codec = manager_.find(desc);
 
            unsigned config_head_bit_size, body_bit_size;
            codec->base_max_size(&config_head_bit_size, desc, HEAD);
            codec->base_max_size(&body_bit_size, desc, BODY);
 
            int32 dccl_id = id_internal_const(desc, user_id);
            unsigned id_bit_size = 0;
            if (!omit_id)
                id_codec()->field_size(&id_bit_size, static_cast<uint32>(dccl_id), nullptr);
 
            const unsigned bit_size = id_bit_size + config_head_bit_size + body_bit_size;
 
            const unsigned byte_size = ceil_bits2bytes(config_head_bit_size + id_bit_size) +
                                       ceil_bits2bytes(body_bit_size);
 
            const unsigned allowed_byte_size = desc->options().GetExtension(dccl::msg).max_bytes();
            const unsigned allowed_bit_size = allowed_byte_size * BITS_IN_BYTE;
 
            std::string hash;
            if (manager_.has_hash(desc))
                hash = hash_as_string(manager_.hash(desc));
 
            std::string message_name;
            if (!omit_id)
                message_name += std::to_string(dccl_id) + ": ";
            message_name += std::string(desc->full_name()) + " {" + hash + "}";
            std::string guard = build_guard_for_console_output(message_name, '=');
            std::string bits_dccl_head_str = "dccl.id head";
            std::string bits_user_head_str = "user head";
            std::string bits_body_str = "body";
            std::string bits_padding_str = "padding to full byte";
 
            const int bits_width = 40;
            const int spaces = 8;
            std::string indent = std::string(spaces, ' ');
 
            *os << guard << " " << message_name << " " << guard << "\n"
                << "Actual maximum size of message: " << byte_size << " bytes / "
                << byte_size * BITS_IN_BYTE << " bits\n"
                << indent << bits_dccl_head_str << std::setfill('.')
                << std::setw(bits_width - bits_dccl_head_str.size()) << id_bit_size << "\n"
                << indent << bits_user_head_str << std::setfill('.')
                << std::setw(bits_width - bits_user_head_str.size()) << config_head_bit_size << "\n"
                << indent << bits_body_str << std::setfill('.')
                << std::setw(bits_width - bits_body_str.size()) << body_bit_size << "\n"
                << indent << bits_padding_str << std::setfill('.')
                << std::setw(bits_width - bits_padding_str.size())
                << byte_size * BITS_IN_BYTE - bit_size << "\n"
                << "Allowed maximum size of message: " << allowed_byte_size << " bytes / "
                << allowed_bit_size << " bits\n";
 
            std::string header_str = "Header";
            std::string header_guard = build_guard_for_console_output(header_str, '-');
 
            *os << header_guard << " " << header_str << " " << header_guard << "\n";
            *os << bits_dccl_head_str << std::setfill('.')
                << std::setw(bits_width - bits_dccl_head_str.size() + spaces) << id_bit_size << " {"
                << (omit_id ? std::string("omit_id: true") : id_codec()->name()) << "}\n";
            codec->base_info(os, desc, HEAD);
            //            *os << std::string(header_str.size() + 2 + 2*header_guard.size(), '-') << "\n";
 
            std::string body_str = "Body";
            std::string body_guard = build_guard_for_console_output(body_str, '-');
 
            *os << body_guard << " " << body_str << " " << body_guard << "\n";
            codec->base_info(os, desc, BODY);
            //            *os << std::string(body_str.size() + 2 + 2*body_guard.size(), '-') << "\n";
 
            //            *os << std::string(desc->full_name().size() + 2 + 2*guard.size(), '=') << "\n";
            os->flush();
 
            if (is_dlog)
                dlog.is(INFO) && dlog << ss.str() << std::endl;
        }
        catch (Exception& e)
        {
            dlog.is(DEBUG1) &&
                dlog << "Message " << desc->full_name()
                     << " cannot provide information due to invalid configuration. Reason: "
                     << e.what() << std::endl;
        }
    }
}
 
void dccl::Codec::encrypt(std::string* s, const std::string& nonce /* message head */)
{
#if DCCL_HAS_CRYPTOPP
    using namespace CryptoPP;
 
    std::string iv;
    SHA256 hash;
    StringSource unused(nonce, true, new HashFilter(hash, new StringSink(iv)));
 
    CTR_Mode<AES>::Encryption encryptor;
    encryptor.SetKeyWithIV((byte*)crypto_key_.c_str(), crypto_key_.size(), (byte*)iv.c_str());
 
    std::string cipher;
    StreamTransformationFilter in(encryptor, new StringSink(cipher));
    in.Put((byte*)s->c_str(), s->size());
    in.MessageEnd();
    *s = cipher;
#endif
}
 
void dccl::Codec::decrypt(std::string* s, const std::string& nonce)
{
#if DCCL_HAS_CRYPTOPP
    using namespace CryptoPP;
 
    std::string iv;
    SHA256 hash;
    StringSource unused(nonce, true, new HashFilter(hash, new StringSink(iv)));
 
    CTR_Mode<AES>::Decryption decryptor;
    decryptor.SetKeyWithIV((byte*)crypto_key_.c_str(), crypto_key_.size(), (byte*)iv.c_str());
 
    std::string recovered;
 
    StreamTransformationFilter out(decryptor, new StringSink(recovered));
    out.Put((byte*)s->c_str(), s->size());
    out.MessageEnd();
    *s = recovered;
#endif
}
 
void dccl::Codec::load_library(const std::string& library_path)
{
    void* handle = dlopen(library_path.c_str(), RTLD_LAZY);
    if (handle)
        dl_handles_.push_back(handle);
    load_library(handle);
}
 
void dccl::Codec::load_library(void* dl_handle)
{
    if (!dl_handle)
        throw(Exception("Null shared library handle passed to load_library"));
 
    // load any shared library codecs
    void (*dccl_load_ptr)(dccl::Codec*);
    dccl_load_ptr = (void (*)(dccl::Codec*))dlsym(dl_handle, "dccl3_load");
    if (dccl_load_ptr)
        (*dccl_load_ptr)(this);
}
 
void dccl::Codec::unload_library(void* dl_handle)
{
    if (!dl_handle)
        throw(Exception("Null shared library handle passed to unload_library"));
 
    // unload any shared library codecs
    void (*dccl_unload_ptr)(dccl::Codec*);
    dccl_unload_ptr = (void (*)(dccl::Codec*))dlsym(dl_handle, "dccl3_unload");
    if (dccl_unload_ptr)
        (*dccl_unload_ptr)(this);
}
 
void dccl::Codec::set_crypto_passphrase(
    const std::string& passphrase,
    const std::set<int32>& do_not_encrypt_ids /*= std::set<int32>()*/)
{
    if (!crypto_key_.empty())
        crypto_key_.clear();
    skip_crypto_ids_.clear();
 
#if DCCL_HAS_CRYPTOPP
    using namespace CryptoPP;
 
    SHA256 hash;
    StringSource unused(passphrase, true, new HashFilter(hash, new StringSink(crypto_key_)));
 
    dlog.is(DEBUG1) && dlog << "Cryptography enabled with given passphrase" << std::endl;
#else
    dlog.is(DEBUG1) && dlog << "Cryptography disabled because DCCL was compiled without support of "
                               "Crypto++. Install Crypto++ and recompile to enable cryptography."
                            << std::endl;
#endif
 
    skip_crypto_ids_ = do_not_encrypt_ids;
}
 
void dccl::Codec::info_all(std::ostream* param_os /*= 0 */) const
{
    bool is_dlog = false;
    if (!param_os || param_os == &dlog)
        is_dlog = true;
    std::stringstream ss;
    std::ostream* os = (is_dlog) ? &ss : param_os;
    if (!is_dlog || dlog.check(INFO))
    {
        std::string codec_str = "Dynamic Compact Control Language (DCCL) Codec";
        std::string codec_guard = build_guard_for_console_output(codec_str, '|');
 
        *os << codec_guard << " " << codec_str << " " << codec_guard << "\n";
        *os << id2desc_.size() << " messages loaded.\n";
        *os << "Field sizes are in bits unless otherwise noted." << "\n";
 
        for (auto it : id2desc_) info(it.second, os, it.first);
        os->flush();
 
        if (is_dlog)
            dlog.is(INFO) && dlog << ss.str() << std::endl;
    }
}
 
void dccl::Codec::set_id_codec(const std::string& id_codec_name)
{
    // we must reload messages after setting the id_codec
    unload_all();
 
    id_codec_ = id_codec_name;
    // make sure the id codec exists
    id_codec();
}
 
std::string dccl::Codec::build_guard_for_console_output(std::string& base, char guard_char) const
{
    // Only guard if possible, otherwise return an empty string rather than throwing a std::length_error.
    return (base.size() < console_width_)
               ? std::string((console_width_ - base.size()) / 2, guard_char)
               : std::string();
}
 
std::string dccl::Codec::get_all_error_fields_in_message(const google::protobuf::Message& message,
                                                         uint8_t depth /*= 1 */)
{
    // This is largely taken from google::protobuf::ReflectionOps::FindInitializationErrors(), which is called by
    // google::protobuf::Message::FindInitializationErrors(). The Message implementation is not used as they force a
    // prefix of parent message onto fields, which would require a split function to break by delimiter '.' should we
    // want to reflect upon sub-messages and get field numbers.
 
    std::stringstream output_stream;
 
    const google::protobuf::Descriptor* descriptor = message.GetDescriptor();
    const google::protobuf::Reflection* reflection = message.GetReflection();
    const uint8_t depth_spacing = 4;
 
    // Check required fields of this message.
    const int32_t field_count = descriptor->field_count();
 
    for (int32_t index = 0; index < field_count; ++index)
    {
        if (descriptor->field(index)->is_required())
        {
            if (!reflection->HasField(message, descriptor->field(index)))
            {
                output_stream << std::string(depth * depth_spacing, ' ')
                              << descriptor->field(index)->number() << ": "
                              << descriptor->field(index)->name() << "\n";
            }
        }
    }
 
    // Check sub-messages.
    std::vector<const google::protobuf::FieldDescriptor*> fields;
    reflection->ListFields(message, &fields);
 
    for (const google::protobuf::FieldDescriptor* field : fields)
    {
        if (field->cpp_type() == google::protobuf::FieldDescriptor::CPPTYPE_MESSAGE)
        {
            output_stream << std::string(depth * depth_spacing, ' ') << field->number() << ": "
                          << field->name() << "\n";
 
            if (field->is_repeated())
            {
                int32_t size = reflection->FieldSize(message, field);
 
                for (int32_t index = 0; index < size; ++index)
                {
                    const google::protobuf::Message& sub_message =
                        reflection->GetRepeatedMessage(message, field, index);
 
                    output_stream << std::string((depth + 1) * depth_spacing, ' ') << "[" << index
                                  << "]: " << "\n";
 
                    output_stream << get_all_error_fields_in_message(sub_message, depth + 2);
                }
            }
            else
            {
                const google::protobuf::Message& sub_message =
                    reflection->GetMessage(message, field);
                output_stream << get_all_error_fields_in_message(sub_message, depth + 1);
            }
        }
    }
 
    return output_stream.str();
}