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DaqFromIStream.cc

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/*
 *  DaqFromIStream.cc
 *  FileReadoutFormat
 *
 *  Created by Simon Patton on 7/18/10.
 *  Copyright 2010 DayaBay Collaboration. All rights reserved.
 *
 */
#include "FileReadoutFormat/DaqFromIStream.h"

#include <istream>
#include <string>
#include <cstring>

#include "DaqReadoutFormat/ByteBuffer.h"
#include "FileReadoutFormat/DaqFormatFromBytes.h"

using DybDaq::ByteBuffer;
using DybDaq::FileBuffer;
using DybDaq::DaqFormatFromBytes;
using DybDaq::DaqFromIStream;
using std::ifstream;
using std::istream;
using std::string;

static const unsigned int DEFAULT_BUFFER_SIZE = 2 * ByteBuffer::BYTES_IN_INT;

DaqFromIStream::DaqFromIStream() :
  m_istream(0),
  m_daqFromBytes(new DaqFormatFromBytes()) {
}

DaqFromIStream::~DaqFromIStream() {
    delete m_daqFromBytes;
    if (0 != m_istream) {
        delete m_istream;
    }
}

bool DaqFromIStream::close() {
    if (0 != m_istream) {
        closeStream(*m_istream);
        delete m_istream;
        m_istream = 0;
    }
    return true;
}

bool DaqFromIStream::hasIStream() const {
    return 0 != m_istream;
}

bool DaqFromIStream::open() {
    m_istream = openStream();
    return hasIStream();
}

const FileBuffer* DaqFromIStream::nextRecord() {
        ByteBuffer* buffer = new ByteBuffer(new char[DEFAULT_BUFFER_SIZE],
                                        DEFAULT_BUFFER_SIZE);
        m_istream->read(buffer->cursor(),
                   2 * ByteBuffer::BYTES_IN_INT);
        if (m_istream->eof()) {
                return 0;
        }
        
        unsigned int size = buffer->readUnsignedInt(4);
        unsigned int lengthInBytes = size * ByteBuffer::BYTES_IN_INT;
        const FileBuffer* result = 0;
    unsigned int begin = 0;
        while (0 == result && buffer->capacity() != lengthInBytes) {
                if (lengthInBytes > buffer->capacity()) {
                        ByteBuffer* previousBuffer = buffer;
                        buffer = new ByteBuffer(new char[lengthInBytes],
                                                                        lengthInBytes);
                        unsigned int bytesRead = previousBuffer->limit();
            previousBuffer->position(begin);
                        memcpy(buffer->cursor(),
                                   previousBuffer->cursor(),
                                   bytesRead);
                        buffer->limit(bytesRead);
            previousBuffer->release();
                }
                unsigned int bytesRead = buffer->limit();
                m_istream->read(buffer->cursor() + bytesRead,
                       buffer->capacity() - bytesRead);
                buffer->limit(buffer->capacity());
        begin = buffer->position();
                result = m_daqFromBytes->createFileBuffer(buffer);
                if (0 == result) {
                        lengthInBytes = m_daqFromBytes->additionalCapacity() + buffer->capacity();
                }
        }
        return result;
}

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