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ByteBuffer.cc

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/*
 *  ByteBuffer.cc
 *  DaqReadoutFormat
 *
 *  Created by Simon Patton on 7/18/10.
 *  Copyright 2010 DayaBay Collaboration. All rights reserved.
 *
 */

#include "DaqReadoutFormat/ByteBuffer.h"

#include <string>
#include <cstring> 

using DybDaq::ByteBuffer;

const unsigned int ByteBuffer::BYTES_IN_INT = 4;

ByteBuffer::ByteBuffer(char* contents,
                                           unsigned int capacity) :
m_buffer(contents),
m_capacity(capacity),
m_limit(capacity),
m_position(0),
m_count(1) {
}

ByteBuffer::~ByteBuffer() {
        if (0 != m_buffer) {
                delete m_buffer;
        }
}

const char* ByteBuffer::grab() const {
        ++m_count;
        return m_buffer + m_position;
}

void ByteBuffer::release() const {
        --m_count;
        if (0 == m_count) {
                delete this;
        }
}

const unsigned int ByteBuffer::capacity() const {
        return m_capacity;
}

const char* ByteBuffer::cursor() const {
    return m_buffer + m_position;
}

const unsigned int ByteBuffer::remaining() const {
        return m_limit - m_position;
}

const bool ByteBuffer::hasRemaining() const {
        return 0 != remaining();
}

const unsigned int ByteBuffer::limit() const {
        return m_limit;
}

const ByteBuffer* ByteBuffer::limit(unsigned int newLimit) const {
        m_limit = newLimit;
        return this;
}

const unsigned int ByteBuffer::position() const {
        return m_position;
}

const ByteBuffer* ByteBuffer::position(unsigned int newPosition) const {
        m_position = newPosition;
        return this;
}

const char ByteBuffer::readChar(unsigned int index) const {
        return (m_buffer + index)[0];
}

const unsigned int ByteBuffer::readUnsignedInt(unsigned int index) const {
        return *((unsigned int*)(m_buffer + index));
}

char* ByteBuffer::cursor() {
    return m_buffer + m_position;
}

const unsigned int ByteBuffer::put(const char* source,
                                   const unsigned int length) {
    const unsigned int spaceLeft = remaining();
    if (length > spaceLeft) {
        memcpy(m_buffer + m_position,
               source,
               spaceLeft);
        m_position += spaceLeft;
        return length - spaceLeft;
    }
    memcpy(m_buffer + m_position,
           source,
           length);
    return 0;
}

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