source: trunk/src/core2/RpSerialBuffer.cc @ 3177

/*
 * ======================================================================
 *  Rappture::SerialBuffer
 *
 *  AUTHOR:  Michael McLennan, Purdue University
 *           Carol X Song, Purdue University
 *
 *  Copyright (c) 2004-2012  HUBzero Foundation, LLC
 * ----------------------------------------------------------------------
 *  See the file "license.terms" for information on usage and
 *  redistribution of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 * ======================================================================
 */
#include "RpSerialBuffer.h"

#ifdef BIGENDIAN
#  define ENDIAN_FOR_LOOP(var,size)  \
     for (var=size-1; var >= 0; var--)
#else
#  define ENDIAN_FOR_LOOP(var,size)  \
     for (var=0; var < size; var++)
#endif

using namespace Rappture;

/**
 * Construct an empty SerialBuffer.
 */
SerialBuffer::SerialBuffer()
  : _buffer(),
    _pos(0)
{
}

/**
 * Construct a SerialBuffer loaded with bytes produced by another
 * SerialBuffer.  This is used to decode information from the buffer.
 *
 * @param bytes pointer to bytes being decoded.
 * @param nbytes number of bytes being decoded.
 */
SerialBuffer::SerialBuffer(const char* bytes, int nbytes)
  : _buffer(),
    _pos(0)
{
    _buffer.reserve(nbytes);
    while (nbytes-- > 0) {
        _buffer.push_back( *bytes++ );
    }
}

/**
 * Copy constructor
 */
SerialBuffer::SerialBuffer(const SerialBuffer& sb)
  : _buffer(sb._buffer),
    _pos(0)  // auto-rewind
{
}

/**
 * Assignment operator
 */
SerialBuffer&
SerialBuffer::operator=(const SerialBuffer& sb)
{
    _buffer = sb._buffer;
    _pos = 0;  // auto-rewind
    return *this;
}

SerialBuffer::~SerialBuffer()
{
}

/**
 * Get the bytes currently stored in the buffer.  These bytes can
 * be stored, and used later to construct another SerialBuffer to
 * decode the information.
 *
 * @return Pointer to the bytes in the buffer.
 */
const char*
SerialBuffer::bytes() const
{
    return &_buffer[0];
}

/**
 * Get the number of bytes currently stored in the buffer.
 * @return Number of the bytes in the buffer.
 */
int
SerialBuffer::size() const
{
    return _buffer.size();
}

/**
 * Clear the buffer, making it empty.
 */
SerialBuffer&
SerialBuffer::clear()
{
    _buffer.clear();
    return *this;
}

SerialBuffer&
SerialBuffer::writeChar(char cval)
{
    _buffer.push_back(cval);
    return *this;
}

SerialBuffer&
SerialBuffer::writeInt(int ival)
{
    char *ptr = (char*)(&ival);
    unsigned int i = 0;

    ENDIAN_FOR_LOOP(i, sizeof(int)) {
        _buffer.push_back(ptr[i]);
    }
    return *this;
}

SerialBuffer&
SerialBuffer::writeDouble(double dval)
{
    char *ptr = (char*)(&dval);
    unsigned int i = 0;

    ENDIAN_FOR_LOOP(i, sizeof(double)) {
        _buffer.push_back(ptr[i]);
    }
    return *this;
}

SerialBuffer&
SerialBuffer::writeString(const char* sval)
{
    while (*sval != '\0') {
        _buffer.push_back(*sval++);
    }
    _buffer.push_back('\0');
    return *this;
}

SerialBuffer&
SerialBuffer::writeBytes(const char* bval, int nbytes)
{
    writeInt(nbytes);
    while (nbytes-- > 0) {
        _buffer.push_back(*bval++);
    }
    return *this;
}

void
SerialBuffer::rewind()
{
    _pos = 0;
}

int
SerialBuffer::atEnd() const
{
    return ((unsigned int)_pos >= _buffer.size());
}

char
SerialBuffer::readChar()
{
    char c = '\0';
    if ((unsigned int)_pos < _buffer.size()) {
        c = _buffer[_pos++];
    }
    return c;
}

int
SerialBuffer::readInt()
{
    int ival = 0;
    char *ptr = (char*)(&ival);
    unsigned int i = 0;

    ENDIAN_FOR_LOOP(i, sizeof(int)) {
        if ((unsigned int)_pos < _buffer.size()) {
            ptr[i] = _buffer[_pos++];
        }
    }
    return ival;
}

double
SerialBuffer::readDouble()
{
    double dval = 0;
    char *ptr = (char*)(&dval);
    unsigned int i = 0;

    ENDIAN_FOR_LOOP(i, sizeof(double)) {
        if ((unsigned int)_pos < _buffer.size()) {
            ptr[i] = _buffer[_pos++];
        }
    }
    return dval;
}

std::string
SerialBuffer::readString()
{
    std::string sval;
    char c;
    while ((unsigned int)_pos < _buffer.size()) {
        c = _buffer[_pos++];
        if (c == '\0') {
            break;
        } else {
            sval.push_back(c);
        }
    }
    return sval;
}

std::vector<char>
SerialBuffer::readBytes()
{
    int nbytes;
    std::vector<char> bval;

    nbytes = readInt();
    while ((unsigned int)_pos < _buffer.size() && nbytes-- > 0) {
        bval.push_back( _buffer[_pos++] );
    }
    return bval;
}