endianness.cc

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#include "endianness.hh"
#include <iostream>
#include <boost/tuple/tuple.hpp>
#include <boost/lexical_cast.hpp>

namespace Typelib {
    size_t const CompileEndianSwapVisitor::FLAG_SKIP;
    size_t const CompileEndianSwapVisitor::FLAG_ARRAY;
    size_t const CompileEndianSwapVisitor::FLAG_END;
    size_t const CompileEndianSwapVisitor::FLAG_SWAP_4;
    size_t const CompileEndianSwapVisitor::FLAG_SWAP_8;

    size_t const CompileEndianSwapVisitor::SizeOfEnum;

    void CompileEndianSwapVisitor::skip(int skip_size)
    { 
        size_t size = m_compiled.size();
        if (m_compiled.size() > 1 && m_compiled[size - 2] == FLAG_SKIP)
            m_compiled[size - 1] += skip_size;
        else
        {
            m_compiled.push_back(FLAG_SKIP);
            m_compiled.push_back(skip_size);
        }
    }

    bool CompileEndianSwapVisitor::visit_ (Numeric const& type)
    {
        switch(type.getSize())
        {
        case 1:
            skip(1);
            return true;
        case 2:
            m_compiled.push_back(m_output_index + 1);
            m_compiled.push_back(m_output_index);
            return true;

        case 4:
            m_compiled.push_back(FLAG_SWAP_4);
            return true;

        case 8:
            m_compiled.push_back(FLAG_SWAP_8);
            return true;

        default:
            throw UnsupportedEndianSwap("objects of size " + boost::lexical_cast<std::string>(type.getSize()));
        }
    }

    bool CompileEndianSwapVisitor::visit_ (Enum const& type)
    {
        for (int i = SizeOfEnum - 1; i >= 0; --i)
            m_compiled.push_back(m_output_index + i);
        return true;
    }

    bool CompileEndianSwapVisitor::visit_ (OpaqueType const& type)
    { throw UnsupportedEndianSwap("opaque"); }
    bool CompileEndianSwapVisitor::visit_ (Pointer const& type)
    { throw UnsupportedEndianSwap("pointers"); }
    bool CompileEndianSwapVisitor::visit_ (Array const& type)
    {
        if (type.getIndirection().getCategory() == Type::Array)
        {
            size_t current_size = m_compiled.size();
            visit_(dynamic_cast<Array const&>(type.getIndirection()));
            m_compiled[current_size + 1] *= type.getDimension();
            return true;
        }

        m_compiled.push_back(FLAG_ARRAY);
        m_compiled.push_back(type.getDimension());
        m_compiled.push_back(type.getIndirection().getSize());

        size_t current_size = m_compiled.size();
        TypeVisitor::visit_(type);

        if (m_compiled.size() == current_size + 2 && m_compiled[current_size] == FLAG_SKIP)
        {
            m_compiled[current_size - 3] = FLAG_SKIP;
            m_compiled[current_size - 2] = m_compiled[current_size + 1] * type.getDimension();
            m_compiled.pop_back();
            m_compiled.pop_back();
            m_compiled.pop_back();
        }
        else
            m_compiled.push_back(FLAG_END);

        return true;
    }

    bool CompileEndianSwapVisitor::visit_ (Container const& type)
    { throw UnsupportedEndianSwap("containers"); }

    bool CompileEndianSwapVisitor::visit_ (Compound const& type)
    {
        size_t base_index = m_output_index;

        typedef Compound::FieldList Fields;
        Fields const& fields(type.getFields());
        Fields::const_iterator const end = fields.end();

        for (Fields::const_iterator it = fields.begin(); it != end; ++it)
        {
            size_t new_index = base_index + it->getOffset();
            if (new_index < m_output_index)
                continue;
            else if (new_index > m_output_index)
                skip(new_index - m_output_index);

            m_output_index = new_index;
            dispatch(it->getType());
            m_output_index = new_index + it->getType().getSize();
        }
        return true;
    }

    void CompileEndianSwapVisitor::apply(Type const& type)
    {
        m_output_index = 0;
        m_compiled.clear();
        TypeVisitor::apply(type);
    }

    std::pair<size_t, std::vector<size_t>::const_iterator> 
        CompileEndianSwapVisitor::swap(
            size_t output_offset, size_t input_offset,
            std::vector<size_t>::const_iterator it,
            std::vector<size_t>::const_iterator end,
            Value in, Value out)
    {
        uint8_t* input_buffer = reinterpret_cast<uint8_t*>(in.getData());
        uint8_t* output_buffer = reinterpret_cast<uint8_t*>(out.getData());
        while(it != end)
        {
            switch(*it)
            {
            case FLAG_SKIP:
                {
                    size_t skip_size = *(++it);
                    for (size_t i = 0; i < skip_size; ++i)
                    {
                        output_buffer[output_offset] = input_buffer[output_offset];
                        output_offset++;
                    }
                }
                break;
            case FLAG_SWAP_4:
                {
                    reinterpret_cast<uint32_t&>(output_buffer[output_offset]) = 
                        Typelib::Endian::swap(reinterpret_cast<uint32_t const&>(input_buffer[output_offset]));
                    output_offset += 4;
                }
                break;
            case FLAG_SWAP_8:
                {
                    reinterpret_cast<uint64_t&>(output_buffer[output_offset]) = 
                        Typelib::Endian::swap(reinterpret_cast<uint64_t const&>(input_buffer[output_offset]));
                    output_offset += 8;
                }
                break;
            case FLAG_ARRAY:
                {
                    size_t array_size = *(++it);
                    size_t element_size = *(++it);

                    // And swap as many elements as needed
                    ++it;

                    std::vector<size_t>::const_iterator array_end;
                    for (size_t i = 0; i < array_size; ++i)
                    {
                        boost::tie(output_offset, array_end) = 
                            swap(output_offset, input_offset + element_size * i, 
                                it, end, in, out);
                    }
                    it = array_end;
                }
                break;
            case FLAG_END:
                return make_pair(output_offset, it);
            default:
                {
                    output_buffer[output_offset] = input_buffer[input_offset + *it];
                    ++output_offset;
                }
                break;
            }

            ++it;
        }

        return make_pair(output_offset, it);
    }

    void CompileEndianSwapVisitor::display()
    {
        std::string indent = "";
        std::vector<size_t>::const_iterator it, end;
        for (it = m_compiled.begin(); it != m_compiled.end(); ++it)
        {
            switch(*it)
            {
                case FLAG_SKIP:
                    std::cout << std::endl << indent << "SKIP " << *(++it) << std::endl;
                    break;
                case FLAG_ARRAY:
                    std::cout << std::endl << indent << "ARRAY " << *(++it) << " " << *(++it) << std::endl;
                    indent += "  ";
                    break;
                case FLAG_END:
                    indent.resize(indent.length() - 2);
                    std::cout << std::endl << indent << "END" << std::endl;
                    break;
                default:
                    std::cout << " " << *it;
            }
        }
    }
}