srs/trunk/src/kernel/srs_kernel_stream.hpp

/*
The MIT License (MIT)

Copyright (c) 2013-2015 winlin

Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software is furnished to do so,
subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

#ifndef SRS_KERNEL_STREAM_HPP
#define SRS_KERNEL_STREAM_HPP

/*
#include <srs_kernel_stream.hpp>
*/

#include <srs_core.hpp>

#include <sys/types.h>
#include <string>

/**
* bytes utility, used to:
* convert basic types to bytes,
* build basic types from bytes.
*/
class SrsStream
{
private:
    char* p;
    char* pp;
    char* _bytes;
    int _size;
public:
    SrsStream();
    virtual ~SrsStream();
public:
    /**
    * initialize the stream from bytes.
    * @bytes, the bytes to convert from/to basic types.
    * @size, the size of bytes.
    * @remark, stream never free the bytes, user must free it.
    * @remark, return error when bytes NULL.
    * @remark, return error when size is not positive.
    */
    virtual int initialize(char* bytes, int size);
// get the status of stream
public:
    /**
    * get data of stream, set by initialize.
    * current bytes = data() + pos()
    */
    virtual char* data();
    /**
    * the total stream size, set by initialize.
    * left bytes = size() - pos().
    */
    virtual int size();
    /**
    * tell the current pos.
    */
    virtual int pos();
    /**
    * whether stream is empty.
    * if empty, user should never read or write.
    */
    virtual bool empty();
    /**
    * whether required size is ok.
    * @return true if stream can read/write specified required_size bytes.
    * @remark assert required_size positive.
    */
    virtual bool require(int required_size);
// to change stream.
public:
    /**
    * to skip some size.
    * @param size can be any value. positive to forward; nagetive to backward.
    * @remark to skip(pos()) to reset stream.
    * @remark assert initialized, the data() not NULL.
    */
    virtual void skip(int size);
public:
    /**
    * get 1bytes char from stream.
    */
    virtual int8_t read_1bytes();
    /**
    * get 2bytes int from stream.
    */
    virtual int16_t read_2bytes();
    /**
    * get 3bytes int from stream.
    */
    virtual int32_t read_3bytes();
    /**
    * get 4bytes int from stream.
    */
    virtual int32_t read_4bytes();
    /**
    * get 8bytes int from stream.
    */
    virtual int64_t read_8bytes();
    /**
    * get string from stream, length specifies by param len.
    */
    virtual std::string read_string(int len);
    /**
    * get bytes from stream, length specifies by param len.
    */
    virtual void read_bytes(char* data, int size);
public:
    /**
    * write 1bytes char to stream.
    */
    virtual void write_1bytes(int8_t value);
    /**
    * write 2bytes int to stream.
    */
    virtual void write_2bytes(int16_t value);
    /**
    * write 4bytes int to stream.
    */
    virtual void write_4bytes(int32_t value);
    /**
    * write 3bytes int to stream.
    */
    virtual void write_3bytes(int32_t value);
    /**
    * write 8bytes int to stream.
    */
    virtual void write_8bytes(int64_t value);
    /**
    * write string to stream
    */
    virtual void write_string(std::string value);
    /**
    * write bytes to stream
    */
    virtual void write_bytes(char* data, int size);
};

/**
 * the bit stream.
 */
class SrsBitStream
{
private:
    int8_t cb;
    u_int8_t cb_left;
    SrsStream* stream;
public:
    SrsBitStream();
    virtual ~SrsBitStream();
public:
    virtual int initialize(SrsStream* s);
    virtual bool empty();
    virtual int8_t read_bit();
};

#endif