/********************************************************************************

* *

* This file is part of IfcOpenShell. *

* *

* IfcOpenShell is free software: you can redistribute it and/or modify *

* it under the terms of the Lesser GNU General Public License as published by *

* the Free Software Foundation, either version 3.0 of the License, or *

* (at your option) any later version. *

* *

* IfcOpenShell 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 *

* Lesser GNU General Public License for more details. *

* *

* You should have received a copy of the Lesser GNU General Public License *

* along with this program. If not, see <http://www.gnu.org/licenses/>. *

* *

********************************************************************************/

#include "IfcGlobalId.h"

#include "IfcException.h"

#include "IfcLogger.h"

#include <algorithm>

#include <boost/lexical_cast.hpp>

#include <boost/uuid/uuid.hpp>

#include <boost/uuid/uuid_generators.hpp>

#include <boost/uuid/uuid_io.hpp>

#include <boost/version.hpp>

#include <vector>

static const char* chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz_$";

// Converts an unsigned integer into a base64 string of length l

std::string base64(unsigned value, int length) {

const int BASE64 = 64;

std::string result;

result.reserve(length);

while (value != 0U) {

result.push_back(chars[value % BASE64]);

value /= BASE64;

}

while ((int)result.size() != length) {

result.push_back('0');

}

std::reverse(result.begin(), result.end());

return result;

}

// Converts a base64 string into an unsigned integer

unsigned from_base64(const std::string& string) {

std::string::size_type zeros = string.find_first_not_of('0');

unsigned result = 0;

if (zeros != std::string::npos) {

for (std::string::const_iterator i = string.begin() + zeros; i != string.end(); ++i) {

result *= 64;

const char* character = strchr(chars, *i);

if (character == nullptr) {

throw IfcParse::IfcException("Failed to decode GlobalId");

}

result += (unsigned)(character - chars);

}

}

return result;

}

// Compresses the UUID byte array into a base64 representation

std::string compress(unsigned char* value) {

std::string result;

result.reserve(22);

result += base64(value[0], 2);

for (unsigned i = 1; i < 16; i += 3) {

result += base64((value[i] << 16) + (value[i + 1] << 8) + value[i + 2], 4);

}

return result;

}

// Expands the base64 representation into a UUID byte array

void expand(const std::string& s, std::vector<unsigned char>& v) {

v.push_back((unsigned char)from_base64(s.substr(0, 2)));

for (unsigned i = 0; i < 5; ++i) {

unsigned d = from_base64(s.substr(2 + 4 * i, 4));

for (unsigned j = 0; j < 3; ++j) {

v.push_back((d >> (8 * (2 - j))) % 256);

}

}

}

// Define the macro to handle different Boost versions

#if BOOST_VERSION >= 108600

static boost::uuids::basic_random_generator<std::mt19937> gen;

#else

static boost::uuids::basic_random_generator<boost::mt19937> gen;

#endif

IfcParse::IfcGlobalId::IfcGlobalId() {

uuid_data_ = gen();

std::vector<unsigned char> v(uuid_data_.size());

std::copy(uuid_data_.begin(), uuid_data_.end(), v.begin());

string_data_ = compress(v.data());

#if BOOST_VERSION < 104400

formatted_string = boost::lexical_cast<std::string>(uuid_data);

#else

formatted_string_ = boost::uuids::to_string(uuid_data_);

#endif

#ifndef NDEBUG

std::vector<unsigned char> test_vector;

expand(string_data_, test_vector);

boost::uuids::uuid test_uuid;

std::copy(test_vector.begin(), test_vector.end(), test_uuid.begin());

if (uuid_data_ != test_uuid) {

Logger::Message(Logger::LOG_ERROR, "Internal error generating GlobalId");

}

#endif

}

IfcParse::IfcGlobalId::IfcGlobalId(const std::string& string)

: string_data_(string) {

std::vector<unsigned char> result;

expand(string_data_, result);

std::copy(result.begin(), result.end(), uuid_data_.begin());

#if BOOST_VERSION < 104400

formatted_string_ = boost::lexical_cast<std::string>(uuid_data_);

#else

formatted_string_ = boost::uuids::to_string(uuid_data_);

#endif

#ifndef NDEBUG

const std::string test_string = compress(&uuid_data_.data[0]);

if (string_data_ != test_string) {

Logger::Message(Logger::LOG_ERROR, "Internal error generating GlobalId");

}

#endif

}

IfcParse::IfcGlobalId::operator const std::string&() const {

return string_data_;

}

IfcParse::IfcGlobalId::operator const boost::uuids::uuid&() const {

return uuid_data_;

}

const std::string& IfcParse::IfcGlobalId::formatted() const {

return formatted_string_;

}