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/*! \file
* header functions for qmp3frameheader
*/
# ifndef _qmp3frameheader_hh_
# define _qmp3frameheader_hh_
# include <sys/types.h>
# include <string>
/*!
* \brief class for mp3 frame headers
*
* this class models a mp3 frame header mapped in memory
*/
class qmp3frameheader {
private:
/*!
* \brief struct for mp3 frame headers
*
* this struct is defined to match exactly with a mp3 frame header with no change on a little-endian machine
*/
struct header {
u_int32_t
sync1:8, /*!< syncro field. should be 0x0ff */
protection:1, /*!< whether or not the frame has crc */
layer:2, /*!< mpeg frame layer */
version:2, /*!< mpeg frame version */
sync2:3, /*!< syncro field. should be 0x7 */
privat:1, /*!< bit for private use */
padding:1, /*!< whether the frame is one byte larger */
samplerate:2, /*!< sample rate */
bitrate:4, /*!< bit rate */
emphasis:2, /*!< which type of pre-emphasis must be used */
original:1, /*!< original bit stream (1) or copy (0) */
copyright:1, /*!< whether or not is a copyrighted frame */
mode_extension:2, /*!< type of joint stereo coding */
channel_mode:2; /*!< mono or which type of stereo */
};
//! pointer to the header (memory location where it is located)
struct header *header;
public:
/*!
* \brief gets where the frame header is mapped
* \return the memory location where the frame header is mapped
*/
caddr_t getMap();
/*!
* \brief remaps (changes) the location of the header
* \param a the new address of the header
*/
void remap(caddr_t a);
//! length in bytes of a mp3 frame header
static const u_int32_t HEADERSIZE;
static const u_int32_t MASK;
/*!
* \brief looks for (and reuses itself with) the next frame
* \param bufsize the number of bytes where to find the header
* \return the number of (garbage) skipped bytes
*/
u_int32_t setNext(u_int32_t bufsize=HEADERSIZE);
/*!
* \brief looks for (and reuses itself with) the next frame
* \param endstream
* \return the number of (garbage) skipped bytes
*/
u_int32_t setNext(caddr_t endstream);
static const u_int32_t LAYER1, LAYER2, LAYER3;
static const u_int32_t VERSION1, VERSION2, VERSION25, UNDEFINED_VERSION;
/*!
* \brief look for a frame header
* \param a the start searching point
* \param bufsize the number of bytes where to find the header
* \param signature the header must be compatible with this signature
* \param backwards whether to search forwards (by default) or backwards
* \return the address where the header has been found
*/
static caddr_t seek_header(caddr_t a, u_int32_t bufsize=HEADERSIZE, u_int32_t signature=0, bool backwards=false);
static bool compatible(caddr_t p, u_int32_t signature);
bool compatible(qmp3frameheader &h);
bool compatible(u_int32_t);
void print (ostream *os);
bool valid();
static bool valid(caddr_t);
qmp3frameheader();
qmp3frameheader(caddr_t p, u_int32_t bufsize = HEADERSIZE, u_int32_t signature=0);
// direct access to the header
u_int32_t get();
void set(u_int32_t h);
// direct access to the header fields (without checking!!):
enum qmp3frameheaderfield {
SYNC1, SYNC2, _VERSION, LAYER, PROTECTION, BITRATE, SAMPLERATE,
PADDING, PRIVAT, CHANNEL_MODE, MODE_EXTENSION, COPYRIGHT,
ORIGINAL, EMPHASIS
};
u_int32_t getField (enum qmp3frameheaderfield f);
void setField (enum qmp3frameheaderfield f, u_int32_t v);
string getVersion();
string getLayer();
u_int32_t getSamplesPerFrame();
u_int32_t getLength();
u_int32_t getSampleRate();
u_int32_t getBitRate();
u_int32_t getMsDuration();
u_int32_t getSignature();
bool isSilence();
void write(int fd);
};
ostream &operator<<(ostream &os, qmp3frameheader &fh);
# endif
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