path: root/Assembly.cpp

/*
    This file is part of cpp-ethereum.

    cpp-ethereum is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    cpp-ethereum 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 General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with cpp-ethereum.  If not, see <http://www.gnu.org/licenses/>.
*/
/** @file Assembly.cpp
 * @author Gav Wood <i@gavwood.com>
 * @date 2014
 */

#include "Assembly.h"

#include <libethcore/CommonEth.h>

using namespace std;
using namespace eth;

int AssemblyItem::deposit() const
{
    switch (m_type)
    {
    case Operation:
        return c_instructionInfo.at((Instruction)(byte)m_data).ret - c_instructionInfo.at((Instruction)(byte)m_data).args;
    case Push: case PushString: case PushTag: case PushData:
        return 1;
    case Tag:
        return 0;
    }
    assert(false);
}

unsigned Assembly::bytesRequired() const
{
    for (unsigned br = 1;; ++br)
    {
        unsigned ret = 1;
        for (auto const& i: m_data)
            ret += i.second.size();

        for (AssemblyItem const& i: m_items)
            switch (i.m_type)
            {
            case Operation:
                ret++;
                break;
            case PushString:
                ret += 33;
                break;
            case Push:
                ret += 1 + max<unsigned>(1, eth::bytesRequired(i.m_data));
                break;
            case PushTag:
            case PushData:
                ret += 1 + br;
            case Tag:;
            }
        if (eth::bytesRequired(ret) <= br)
            return ret;
    }
}

void Assembly::append(Assembly const& _a)
{
    for (AssemblyItem i: _a.m_items)
    {
        if (i.type() == Tag || i.type() == PushTag)
            i.m_data += m_usedTags;
        append(i);
    }
    m_usedTags += _a.m_usedTags;
    for (auto const& i: _a.m_data)
        m_data.insert(i);
    for (auto const& i: _a.m_strings)
        m_strings.insert(i);

    assert(!_a.m_baseDeposit);
    assert(!_a.m_totalDeposit);
}

void Assembly::append(Assembly const& _a, int _deposit)
{
    if (_deposit > _a.m_deposit)
        throw InvalidDeposit();
    else
    {
        append(_a);
        while (_deposit++ < _a.m_deposit)
            append(Instruction::POP);
    }
}

ostream& Assembly::streamOut(ostream& _out) const
{
    _out << ".code:" << endl;
    for (AssemblyItem const& i: m_items)
        switch (i.m_type)
        {
        case Operation:
            _out << "  " << c_instructionInfo.at((Instruction)(byte)i.m_data).name << endl;
            break;
        case Push:
            _out << "  PUSH " << i.m_data << endl;
            break;
        case PushString:
            _out << "  PUSH \"" << m_strings.at((h256)i.m_data) << "\"" << endl;
            break;
        case PushTag:
            _out << "  PUSH [tag" << i.m_data << "]" << endl;
            break;
        case Tag:
            _out << "tag" << i.m_data << ": " << endl;
            break;
        case PushData:
            _out << "  PUSH [" << h256(i.m_data).abridged() << "]" << endl;
            break;
        }

    if (m_data.size())
    {
        _out << ".data:" << endl;
        for (auto const& i: m_data)
            _out << "  " << i.first.abridged() << ": " << toHex(i.second) << endl;
    }
    return _out;
}

AssemblyItem const& Assembly::append(AssemblyItem const& _i)
{
    m_deposit += _i.deposit();
    m_items.push_back(_i);
    return back();
}

void Assembly::optimise()
{
    std::vector<pair<  vector<int>,  function< vector<AssemblyItem>(vector<AssemblyItem>) >  >> rules;
//  rules.insert(make_pair({(int)Instruction::ADD, (int)Instruction::ADD, -(int)Push}, []() {}));
}

bytes Assembly::assemble() const
{
    bytes ret;

    unsigned totalBytes = bytesRequired();
    ret.reserve(totalBytes);
    vector<unsigned> tagPos(m_usedTags);
    map<unsigned, unsigned> tagRef;
    multimap<h256, unsigned> dataRef;
    unsigned bytesPerTag = eth::bytesRequired(totalBytes);
    byte tagPush = (byte)Instruction::PUSH1 - 1 + bytesPerTag;

    for (AssemblyItem const& i: m_items)
        switch (i.m_type)
        {
        case Operation:
            ret.push_back((byte)i.m_data);
            break;
        case PushString:
        {
            ret.push_back((byte)Instruction::PUSH32);
            unsigned ii = 0;
            for (auto j: m_strings.at((h256)i.m_data))
                if (++ii > 32)
                    break;
                else
                    ret.push_back((byte)j);
            while (ii++ < 32)
                ret.push_back(0);
            break;
        }
        case Push:
        {
            byte b = max<unsigned>(1, eth::bytesRequired(i.m_data));
            ret.push_back((byte)Instruction::PUSH1 - 1 + b);
            ret.resize(ret.size() + b);
            bytesRef byr(&ret.back() + 1 - b, b);
            toBigEndian(i.m_data, byr);
            break;
        }
        case PushTag:
        {
            ret.push_back(tagPush);
            tagRef[ret.size()] = (unsigned)i.m_data;
            ret.resize(ret.size() + bytesPerTag);
            break;
        }
        case PushData:
        {
            ret.push_back(tagPush);
            dataRef.insert(make_pair((h256)i.m_data, ret.size()));
            ret.resize(ret.size() + bytesPerTag);
            break;
        }
        case Tag:
            tagPos[(unsigned)i.m_data] = ret.size();
            break;
        }

    for (auto const& i: tagRef)
    {
        bytesRef r(ret.data() + i.first, bytesPerTag);
        toBigEndian(tagPos[i.second], r);
    }

    if (m_data.size())
    {
        ret.push_back(0);
        for (auto const& i: m_data)
        {
            auto its = dataRef.equal_range(i.first);
            for (auto it = its.first; it != its.second; ++it)
            {
                bytesRef r(ret.data() + it->second, bytesPerTag);
                toBigEndian(ret.size(), r);
            }
            for (auto b: i.second)
                ret.push_back(b);
        }
    }
    return ret;
}