/* vim: set ts=4 sw=4 tw=99 et:

 *

 * Copyright (C) 2012 David Anderson

 *

 * This file is part of JITCraft.

 *

 * JITCraft 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.

 * 

 * Foobar 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

 * JITCraft. If not, see http://www.gnu.org/licenses/.

 */

#ifndef _include_jc_compact_buffer_h_

#define _include_jc_compact_buffer_h_

#include "AllocatorPolicies.h"

#include "Utility.h"

#include "Vector.h"

namespace ke {

class CompactBufferReader

{

    const uint8 *pos_;

    const uint8 *end_;

  public:

    CompactBufferReader(const uint8 *start, const uint8 *end)

      : pos_(start),

        end_(end)

    {

    }

    uint8 readUint8() {

        assert(pos_ < end_);

        return *pos_++;

    }

    uint32 readUint32() {

        uint32 value = 0;

        uint32 shift = 0;

        uint8 byte;

        do {

            byte = readUint8();

            value |= (byte >> 1) << shift;

            shift += 7;

        } while (byte & 1);

        assert(shift < 32);

        return value;

    }

    bool done() const {

        return pos_ == end_;

    }

};

class CompactBufferWriter

{

    Vector<uint8, ZoneAllocatorPolicy> buffer_;

    bool enoughMemory_;

  public:

    CompactBufferWriter()

      : enoughMemory_(true)

    {

    }

    void writeUint8(unsigned value) {

        enoughMemory_ &= buffer_.append(value);

    }

    void writeUint32(unsigned value) {

        do {

            writeUint8(((value & 0x7F) << 1) | (value > 0x7F));

            value >>= 7;

        } while (value);

    }

    uint8 *buffer() const {

        return buffer_.buffer();

    }

    size_t length() const {

        return buffer_.length();

    }

    bool oom() const {

        return !enoughMemory_;

    }

};

}

#endif // _include_jc_compact_buffer_h_