source: xplcommon/src/xplcommon/DataStream.h@ 31:bbd688924703

// Copyright (c) 2013 by István Váradi

// This file is part of libxplcommon, a common utility library for
// development related to X-Plane

// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:

// 1. Redistributions of source code must retain the above copyright notice, this
//    list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright notice,
//    this list of conditions and the following disclaimer in the documentation
//    and/or other materials provided with the distribution.

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
// ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// The views and conclusions contained in the software and documentation are those
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#ifndef XPLCOMMON_DATASTREAM_H
#define XPLCOMMON_DATASTREAM_H
//------------------------------------------------------------------------------

#include "BlockingStream.h"

#include <string>

#include <cstring>

#include <inttypes.h>

//------------------------------------------------------------------------------

namespace xplcommon {

//------------------------------------------------------------------------------

/**
 * A blocking stream with extra functions to read and write values of
 * basic data types. The values are read and written in host
 * byte-order, so this stream does not work properly between machines
 * of different endianness.
 *
 * The reading functions return the value read and you can check of
 * error or interruption only by calling the appropriate
 * functions. The purpose of this behaviour is that the data could be
 * read item-by-item without having to check for the stream's
 * health all the time. Such checks are needed only, if some decision
 * is made, based on the data. In case of an error, the read functions
 * return some well-define default value, typically 0.
 *
 * The writing functions return a boolean value indicating success or
 * failure, but writing can be handled the same way as reading from
 * the point of view of error checking.
 */
class DataStream : public BlockingStream
{
public:
    /**
     * Construct the stream.
     */
    DataStream(BufferedStream& stream);

    /**
     * Template for simple, type-specific reading.
     */
    template <typename T> T readT(T defaultValue = 0);

    /**
     * Read a signed, 8-bit value
     */
    int8_t readS8();

    /**
     * Read an unsigned, 8-bit value
     */
    uint8_t readU8();

    /**
     * Read a signed, 16-bit value
     */
    int16_t readS16();

    /**
     * Read an unsigned, 16-bit value
     */
    uint16_t readU16();

    /**
     * Read a signed, 32-bit value
     */
    int32_t readS32();

    /**
     * Read an unsigned, 32-bit value
     */
    uint32_t readU32();

    /**
     * Read a signed, 64-bit value
     */
    int64_t readS64();

    /**
     * Read an unsigned, 64-bit value
     */
    uint64_t readU64();

    /**
     * Read a float value.
     */
    float readFloat();

    /**
     * Read a double value.
     */
    double readDouble();

    /**
     * Read a long double value.
     */
    long double readLongDouble();

    /**
     * Read a length value. This is a of at most 32 bits, represented
     * by a variable number of bytes for space efficiency.
     *
     * @see writeLength()
     */
    size_t readLength();

    /**
     * Read a string.
     */
    std::string readString();

    /**
     * Read a string into the given buffer. If the string is too large
     * for the buffer, its end will be discarded. A trailing 0 is
     * added in cases!
     *
     * @return the actual length of the string.
     */
    size_t readString(char* dest, size_t capacity);

    /**
     * Write a signed, 8-bit value
     */
    bool writeS8(int8_t x);

    /**
     * Write an unsigned, 8-bit value
     */
    bool writeU8(uint8_t x);

    /**
     * Write a signed, 16-bit value
     */
    bool writeS16(int16_t x);

    /**
     * Write an unsigned, 16-bit value
     */
    bool writeU16(uint16_t x);

    /**
     * Write a signed, 32-bit value
     */
    bool writeS32(int32_t x);

    /**
     * Write an unsigned, 32-bit value
     */
    bool writeU32(uint32_t x);

    /**
     * Write a signed, 64-bit value
     */
    bool writeS64(int64_t x);

    /**
     * Write an unsigned, 64-bit value
     */
    bool writeU64(uint64_t x);

    /**
     * Write a float value.
     */
    bool writeFloat(float x);

    /**
     * Write a double value.
     */
    bool writeDouble(double x);

    /**
     * Write a long double value.
     */
    bool writeLongDouble(long double x);

    /**
     * Write a length value. This a 32-bit value written as a sequence
     * of bytes of variable length. A bytes's lower 7 bits contain
     * parts of the value. The MSB indicates if another byte is left.
     */
    bool writeLength(size_t length);

    /**
     * Write a string. First the string's length is written as a
     * length (see writeLength()), then the characters of the string
     * without the trailing 0.
     */
    bool writeString(const char* s, size_t length);

    /**
     * Write a string. First the string's length is written as a
     * length (see writeLength()), then the characters of the string
     * without the trailing 0.
     */
    bool writeString(const std::string& s);

    /**
     * Write a string. First the string's length is written as a
     * length (see writeLength()), then the characters of the string
     * without the trailing 0.
     */
    bool writeString(const char* s);
};

//------------------------------------------------------------------------------
// Inline definitions
//------------------------------------------------------------------------------

inline DataStream::DataStream(BufferedStream& stream) :
    BlockingStream(stream)
{
}

//------------------------------------------------------------------------------

template <typename T> T DataStream::readT(T defaultValue)
{
    T value = defaultValue;
    read(&value, sizeof(value));
    return value;
}

//------------------------------------------------------------------------------

inline int8_t DataStream::readS8()
{
    return readT<int8_t>(0);
}

//------------------------------------------------------------------------------

inline uint8_t DataStream::readU8()
{
    return readT<uint8_t>(0);
}

//------------------------------------------------------------------------------

inline int16_t DataStream::readS16()
{
    return readT<int16_t>(0);
}

//------------------------------------------------------------------------------

inline uint16_t DataStream::readU16()
{
    return readT<uint16_t>(0);
}

//------------------------------------------------------------------------------

inline int32_t DataStream::readS32()
{
    return readT<int32_t>(0);
}

//------------------------------------------------------------------------------

inline uint32_t DataStream::readU32()
{
    return readT<uint32_t>(0);
}

//------------------------------------------------------------------------------

inline int64_t DataStream::readS64()
{
    return readT<int64_t>(0);
}

//------------------------------------------------------------------------------

inline uint64_t DataStream::readU64()
{
    return readT<uint64_t>(0);
}

//------------------------------------------------------------------------------

inline float DataStream::readFloat()
{
    return readT<float>(0.0);
}

//------------------------------------------------------------------------------

inline double DataStream::readDouble()
{
    return readT<double>(0.0);
}

//------------------------------------------------------------------------------

inline long double DataStream::readLongDouble()
{
    return readT<long double>(0.0);
}

//------------------------------------------------------------------------------

inline bool DataStream::writeS8(int8_t x)
{
    return write(&x, sizeof(x));
}

//------------------------------------------------------------------------------

inline bool DataStream::writeU8(uint8_t x)
{
    return write(&x, sizeof(x));
}

//------------------------------------------------------------------------------

inline bool DataStream::writeS16(int16_t x)
{
    return write(&x, sizeof(x));
}

//------------------------------------------------------------------------------

inline bool DataStream::writeU16(uint16_t x)
{
    return write(&x, sizeof(x));
}

//------------------------------------------------------------------------------

inline bool DataStream::writeS32(int32_t x)
{
    return write(&x, sizeof(x));
}

//------------------------------------------------------------------------------

inline bool DataStream::writeU32(uint32_t x)
{
    return write(&x, sizeof(x));
}

//------------------------------------------------------------------------------

inline bool DataStream::writeS64(int64_t x)
{
    return write(&x, sizeof(x));
}

//------------------------------------------------------------------------------

inline bool DataStream::writeU64(uint64_t x)
{
    return write(&x, sizeof(x));
}

//------------------------------------------------------------------------------

inline bool DataStream::writeFloat(float x)
{
    return write(&x, sizeof(x));
}

//------------------------------------------------------------------------------

inline bool DataStream::writeDouble(double x)
{
    return write(&x, sizeof(x));
}

//------------------------------------------------------------------------------

inline bool DataStream::writeLongDouble(long double x)
{
    return write(&x, sizeof(x));
}

//------------------------------------------------------------------------------

inline bool DataStream::writeString(const char* s, size_t length)
{
    if (!writeLength(length)) return false;
    else return write(s, length);
}

//------------------------------------------------------------------------------

inline bool DataStream::writeString(const std::string& s)
{
    return writeString(s.c_str(), s.length());
}

//------------------------------------------------------------------------------

inline bool DataStream::writeString(const char* s)
{
    return writeString(s, strlen(s));
}

//------------------------------------------------------------------------------

} /* namespace xplcommon */

//------------------------------------------------------------------------------
#endif // XPLCOMMON_DATASTREAM_H

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