// TortoiseSVN - a Windows shell extension for easy version control

// Copyright (C) 2007-2009, 2014, 2020 - TortoiseSVN

// This program 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 2
// of the License, or (at your option) any later version.

// This program 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 this program; if not, write to the Free Software Foundation,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//
#include "stdafx.h"
#include "PackedTime64InStream.h"

///////////////////////////////////////////////////////////////
//
// CPackedTime64InStreamBase
//
///////////////////////////////////////////////////////////////

// construction: nothing to do here

CPackedTime64InStreamBase::CPackedTime64InStreamBase (CCacheFileInBuffer* buffer
                                                     , STREAM_INDEX index)
    : CBinaryInStreamBase (buffer, index)
    , lastValue (0)
{
}

// data access

__time64_t CPackedTime64InStreamBase::GetValue()
{
    // get header info

    unsigned char head = GetByte();

    // read the following data bytes into

    size_t count = ((head / 0x10) & 0x7) +1;

    unsigned char buffer[8] = { 0 };
    *reinterpret_cast<__time64_t*>(buffer) = 0;
    for (size_t i = 0; i < count; ++i)
        buffer[i] = GetByte();

    // now, the buffer contains bits 4 to 64 of the unsigned diff. value
    // the lower 4 bits of the header are value bits 0 .. 3

    __time64_t value = *reinterpret_cast<__time64_t*>(buffer) * 0x10
                     + (head & 0xf);

    // add sign info

    if (head >= 0x80)
        value = -value;

    // get absolute value

    value += lastValue;
    lastValue = value;

    // ready

    return value;
}

// update members in this derived class as well

void CPackedTime64InStreamBase::AutoOpen()
{
    CBinaryInStreamBase::AutoOpen();
    lastValue = 0;
}

void CPackedTime64InStreamBase::AutoClose()
{
    lastValue = 0;
    CBinaryInStreamBase::AutoClose();
}

///////////////////////////////////////////////////////////////
//
// CPackedTime64InStream
//
///////////////////////////////////////////////////////////////

// construction: nothing special to do

CPackedTime64InStream::CPackedTime64InStream ( CCacheFileInBuffer* buffer
                                             , STREAM_INDEX index)
    : TBase (buffer, index)
{
}
