serialize.cc

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#include "serialize.hh"
#include "Base64.hh"
#include "HexDump.hh"
#include "XMLLoader.hh"
#include "XMLElement.hh"
#include "ConfigException.hh"
#include "XMLException.hh"
#include "DeltaBlock.hh"
#include "MemBuffer.hh"
#include "FileOperations.hh"
#include "Version.hh"
#include "Date.hh"
#include "stl.hh"
#include "cstdiop.hh" // for dup()
#include <cstring>
#include <limits>

using std::string;

namespace openmsx {

template<typename Derived>
void ArchiveBase<Derived>::attribute(const char* name, const char* value)
{
        string valueStr(value);
        self().attribute(name, valueStr);
}
template class ArchiveBase<MemOutputArchive>;
template class ArchiveBase<XmlOutputArchive>;


unsigned OutputArchiveBase2::generateID1(const void* p)
{
        #ifdef linux
        assert("Can't serialize ID of object located on the stack" &&
               !addressOnStack(p));
        #endif
        ++lastId;
        assert(!polyIdMap.count(p)); // c++20 contains()
        polyIdMap[p] = lastId;
        return lastId;
}
unsigned OutputArchiveBase2::generateID2(
        const void* p, const std::type_info& typeInfo)
{
        #ifdef linux
        assert("Can't serialize ID of object located on the stack" &&
               !addressOnStack(p));
        #endif
        ++lastId;
        auto key = std::make_pair(p, std::type_index(typeInfo));
        assert(!idMap.count(key)); // c++20 contains()
        idMap[key] = lastId;
        return lastId;
}

unsigned OutputArchiveBase2::getID1(const void* p)
{
        auto v = lookup(polyIdMap, p);
        return v ? *v : 0;
}
unsigned OutputArchiveBase2::getID2(
        const void* p, const std::type_info& typeInfo)
{
        auto v = lookup(idMap, std::make_pair(p, std::type_index(typeInfo)));
        return v ? *v : 0;
}


template<typename Derived>
void OutputArchiveBase<Derived>::serialize_blob(
        const char* tag, const void* data_, size_t len, bool /*diff*/)
{
        auto* data = static_cast<const uint8_t*>(data_);

        string encoding;
        string tmp;
        if (false) {
                // useful for debugging
                encoding = "hex";
                tmp = HexDump::encode(data, len);
        } else if (false) {
                encoding = "base64";
                tmp = Base64::encode(data, len);
        } else {
                encoding = "gz-base64";
                // TODO check for overflow?
                auto dstLen = uLongf(len + len / 1000 + 12 + 1); // worst-case
                MemBuffer<byte> buf(dstLen);
                if (compress2(buf.data(), &dstLen,
                              reinterpret_cast<const Bytef*>(data),
                              uLong(len), 9)
                    != Z_OK) {
                        throw MSXException("Error while compressing blob.");
                }
                tmp = Base64::encode(buf.data(), dstLen);
        }
        this->self().beginTag(tag);
        this->self().attribute("encoding", encoding);
        Saver<string> saver;
        saver(this->self(), tmp, false);
        this->self().endTag(tag);
}

template class OutputArchiveBase<MemOutputArchive>;
template class OutputArchiveBase<XmlOutputArchive>;


void* InputArchiveBase2::getPointer(unsigned id)
{
        auto v = lookup(idMap, id);
        return v ? *v : nullptr;
}

void InputArchiveBase2::addPointer(unsigned id, const void* p)
{
        assert(!idMap.count(id)); // c++20 contains()
        idMap[id] = const_cast<void*>(p);
}

unsigned InputArchiveBase2::getId(const void* ptr) const
{
        for (const auto& p : idMap) {
                if (p.second == ptr) return p.first;
        }
        return 0;
}

template<typename Derived>
void InputArchiveBase<Derived>::serialize_blob(
        const char* tag, void* data, size_t len, bool /*diff*/)
{
        this->self().beginTag(tag);
        string encoding;
        this->self().attribute("encoding", encoding);

        string_view tmp = this->self().loadStr();
        this->self().endTag(tag);

        if (encoding == "gz-base64") {
                auto p = Base64::decode(tmp);
                auto dstLen = uLongf(len); // TODO check for overflow?
                if ((uncompress(reinterpret_cast<Bytef*>(data), &dstLen,
                                reinterpret_cast<const Bytef*>(p.first.data()), uLong(p.second))
                     != Z_OK) ||
                    (dstLen != len)) {
                        throw MSXException("Error while decompressing blob.");
                }
        } else if ((encoding == "hex") || (encoding == "base64")) {
                bool ok = (encoding == "hex")
                        ? HexDump::decode_inplace(tmp, static_cast<uint8_t*>(data), len)
                        : Base64 ::decode_inplace(tmp, static_cast<uint8_t*>(data), len);
                if (!ok) {
                        throw XMLException(
                                "Length of decoded blob different from "
                                "expected value (", len, ')');
                }
        } else {
                throw XMLException("Unsupported encoding \"", encoding, "\" for blob");
        }
}

template class InputArchiveBase<MemInputArchive>;
template class InputArchiveBase<XmlInputArchive>;


void MemOutputArchive::save(const std::string& s)
{
        auto size = s.size();
        byte* buf = buffer.allocate(sizeof(size) + size);
        memcpy(buf, &size, sizeof(size));
        memcpy(buf + sizeof(size), s.data(), size);
}

MemBuffer<byte> MemOutputArchive::releaseBuffer(size_t& size)
{
        return buffer.release(size);
}


void MemInputArchive::load(std::string& s)
{
        size_t length;
        load(length);
        s.resize(length);
        if (length) {
                get(&s[0], length);
        }
}

string_view MemInputArchive::loadStr()
{
        size_t length;
        load(length);
        const byte* p = buffer.getCurrentPos();
        buffer.skip(length);
        return string_view(reinterpret_cast<const char*>(p), length);
}


// Too small inputs don't compress very well (often the compressed size is even
// bigger than the input). It also takes a relatively long time (because often
// compression has a relatively large setup time). I choose this value
// semi-arbitrary. I only made it >= 52 so that the (incompressible) RP5C01
// registers won't be compressed.
static const size_t SMALL_SIZE = 64;
void MemOutputArchive::serialize_blob(const char* /*tag*/, const void* data,
                                      size_t len, bool diff)
{
        // Delta-compress in-memory blobs, see DeltaBlock.hh for more details.
        if (len > SMALL_SIZE) {
                auto deltaBlockIdx = unsigned(deltaBlocks.size());
                save(deltaBlockIdx); // see comment below in MemInputArchive
                deltaBlocks.push_back(diff
                        ? lastDeltaBlocks.createNew(
                                data, static_cast<const uint8_t*>(data), len)
                        : lastDeltaBlocks.createNullDiff(
                                data, static_cast<const uint8_t*>(data), len));
        } else {
                byte* buf = buffer.allocate(len);
                memcpy(buf, data, len);
        }

}

void MemInputArchive::serialize_blob(const char* /*tag*/, void* data,
                                     size_t len, bool /*diff*/)
{
        if (len > SMALL_SIZE) {
                // Usually blobs are saved in the same order as they are loaded
                // (via the serialize_blob() methods in respectively
                // MemOutputArchive and MemInputArchive). In that case keeping
                // track of the deltaBlockIdx in the savestate itself is
                // redundant (it will simply be an increasing value). However
                // in rare cases, via the {begin,end,skip)Section() methods, it
                // is possible that certain blobs are stored in the savestate,
                // but skipped while loading. That's why we do need the index.
                unsigned deltaBlockIdx; load(deltaBlockIdx);
                deltaBlocks[deltaBlockIdx]->apply(static_cast<uint8_t*>(data), len);
        } else {
                memcpy(data, buffer.getCurrentPos(), len);
                buffer.skip(len);
        }
}


XmlOutputArchive::XmlOutputArchive(const string& filename)
        : root("serial")
{
        root.addAttribute("openmsx_version", Version::full());
        root.addAttribute("date_time", Date::toString(time(nullptr)));
        root.addAttribute("platform", TARGET_PLATFORM);
        {
                auto f = FileOperations::openFile(filename, "wb");
                if (!f) goto error;
                int duped_fd = dup(fileno(f.get()));
                if (duped_fd == -1) goto error;
                file = gzdopen(duped_fd, "wb9");
                if (!file) {
                        close(duped_fd);
                        goto error;
                }
                current.push_back(&root);
                return; // success
                // on scope-exit 'File* f' is closed, and 'gzFile file'
                // uses the dup()'ed file descriptor.
        }

error:
        throw XMLException("Could not open compressed file \"", filename, "\"");
}

XmlOutputArchive::~XmlOutputArchive()
{
        assert(current.back() == &root);
        const char* header =
            "<?xml version=\"1.0\" ?>\n"
            "<!DOCTYPE openmsx-serialize SYSTEM 'openmsx-serialize.dtd'>\n";
        gzwrite(file, const_cast<char*>(header), unsigned(strlen(header)));
        string dump = root.dump();
        gzwrite(file, const_cast<char*>(dump.data()), unsigned(dump.size()));
        gzclose(file);
}

void XmlOutputArchive::saveChar(char c)
{
        save(string(1, c));
}
void XmlOutputArchive::save(const string& str)
{
        assert(!current.empty());
        assert(current.back()->getData().empty());
        current.back()->setData(str);
}
void XmlOutputArchive::save(bool b)
{
        assert(!current.empty());
        assert(current.back()->getData().empty());
        current.back()->setData(b ? "true" : "false");
}
void XmlOutputArchive::save(unsigned char b)
{
        save(unsigned(b));
}
void XmlOutputArchive::save(signed char c)
{
        save(int(c));
}
void XmlOutputArchive::save(char c)
{
        save(int(c));
}
void XmlOutputArchive::save(int i)
{
        saveImpl(i);
}
void XmlOutputArchive::save(unsigned u)
{
        saveImpl(u);
}
void XmlOutputArchive::save(unsigned long long ull)
{
        saveImpl(ull);
}

void XmlOutputArchive::attribute(const char* name, const string& str)
{
        assert(!current.empty());
        assert(!current.back()->hasAttribute(name));
        current.back()->addAttribute(name, str);
}
void XmlOutputArchive::attribute(const char* name, int i)
{
        attributeImpl(name, i);
}
void XmlOutputArchive::attribute(const char* name, unsigned u)
{
        attributeImpl(name, u);
}

void XmlOutputArchive::beginTag(const char* tag)
{
        assert(!current.empty());
        auto& elem = current.back()->addChild(tag);
        current.push_back(&elem);
}
void XmlOutputArchive::endTag(const char* tag)
{
        assert(!current.empty());
        assert(current.back()->getName() == tag); (void)tag;
        current.pop_back();
}


XmlInputArchive::XmlInputArchive(const string& filename)
        : rootElem(XMLLoader::load(filename, "openmsx-serialize.dtd"))
{
        elems.emplace_back(&rootElem, 0);
}

string_view XmlInputArchive::loadStr()
{
        if (!elems.back().first->getChildren().empty()) {
                throw XMLException("No child tags expected for primitive type");
        }
        return elems.back().first->getData();
}
void XmlInputArchive::load(string& t)
{
        t = loadStr().str();
}
void XmlInputArchive::loadChar(char& c)
{
        std::string str;
        load(str);
        std::istringstream is(str);
        is >> c;
}
void XmlInputArchive::load(bool& b)
{
        string_view s = loadStr();
        if ((s == "true") || (s == "1")) {
                b = true;
        } else if ((s == "false") || (s == "0")) {
                b = false;
        } else {
                throw XMLException("Bad value found for boolean: ", s);
        }
}

// This function parses a number from a string. It's similar to the generic
// templatized XmlInputArchive::load() method, but _much_ faster. It does
// have some limitations though:
//  - it can't handle leading whitespace
//  - it can't handle extra characters at the end of the string
//  - it can only handle one base (only decimal, not octal or hexadecimal)
//  - it doesn't understand a leading '+' sign
//  - it doesn't detect overflow or underflow (The generic implementation sets
//    a 'bad' flag on the stream and clips the result to the min/max allowed
//    value. Though this 'bad' flag was ignored by the openMSX code).
// This routine is only used to parse strings we've written ourselves (and the
// savestate/replay XML files are not meant to be manually edited). So the
// above limitations don't really matter. And we can use the speed gain.
template<bool IS_SIGNED> struct ConditionalNegate;
template<> struct ConditionalNegate<true> {
        template<typename T> void operator()(bool negate, T& t) {
                if (negate) t = -t; // ok to negate a signed type
        }
};
template<> struct ConditionalNegate<false> {
        template<typename T> void operator()(bool negate, T& /*t*/) {
                assert(!negate); (void)negate; // can't negate unsigned type
        }
};
template<typename T> static inline void fastAtoi(string_view str, T& t)
{
        t = 0;
        bool neg = false;
        size_t i = 0;
        size_t l = str.size();

        static const bool IS_SIGNED = std::numeric_limits<T>::is_signed;
        if (IS_SIGNED) {
                if (l == 0) return;
                if (str[0] == '-') {
                        neg = true;
                        i = 1;
                }
        }
        for (; i < l; ++i) {
                unsigned d = str[i] - '0';
                if (unlikely(d > 9)) {
                        throw XMLException("Invalid integer: ", str);
                }
                t = 10 * t + d;
        }
        // The following stuff does the equivalent of:
        //    if (neg) t = -t;
        // Though this expression triggers a warning on VC++ when T is an
        // unsigned type. This complex template stuff avoids the warning.
        ConditionalNegate<IS_SIGNED> negateFunctor;
        negateFunctor(neg, t);
}
void XmlInputArchive::load(int& i)
{
        string_view str = loadStr();
        fastAtoi(str, i);
}
void XmlInputArchive::load(unsigned& u)
{
        string_view str = loadStr();
        fastAtoi(str, u);
}
void XmlInputArchive::load(unsigned long long& ull)
{
        string_view str = loadStr();
        fastAtoi(str, ull);
}
void XmlInputArchive::load(unsigned char& b)
{
        unsigned i;
        load(i);
        b = i;
}
void XmlInputArchive::load(signed char& c)
{
        int i;
        load(i);
        c = i;
}
void XmlInputArchive::load(char& c)
{
        int i;
        load(i);
        c = i;
}

void XmlInputArchive::beginTag(const char* tag)
{
        auto* child = elems.back().first->findNextChild(
                tag, elems.back().second);
        if (!child) {
                string path;
                for (auto& e : elems) {
                        strAppend(path, e.first->getName(), '/');
                }
                throw XMLException("No child tag \"", tag,
                                   "\" found at location \"", path, '\"');
        }
        elems.emplace_back(child, 0);
}
void XmlInputArchive::endTag(const char* tag)
{
        const auto& elem = *elems.back().first;
        if (elem.getName() != tag) {
                throw XMLException("End tag \"", elem.getName(),
                                   "\" not equal to begin tag \"", tag, "\"");
        }
        auto& elem2 = const_cast<XMLElement&>(elem);
        elem2.clearName(); // mark this elem for later beginTag() calls
        elems.pop_back();
}

void XmlInputArchive::attribute(const char* name, string& t)
{
        try {
                t = elems.back().first->getAttribute(name);
        } catch (ConfigException& e) {
                throw XMLException(std::move(e).getMessage());
        }
}
void XmlInputArchive::attribute(const char* name, int& i)
{
        attributeImpl(name, i);
}
void XmlInputArchive::attribute(const char* name, unsigned& u)
{
        attributeImpl(name, u);
}
bool XmlInputArchive::hasAttribute(const char* name)
{
        return elems.back().first->hasAttribute(name);
}
bool XmlInputArchive::findAttribute(const char* name, unsigned& value)
{
        return elems.back().first->findAttributeInt(name, value);
}
int XmlInputArchive::countChildren() const
{
        return int(elems.back().first->getChildren().size());
}

} // namespace openmsx