#ifndef __RING_BUFFER_H__#define __RING_BUFFER_H__//------------------------------------------------------------------------------//         External functions//------------------------------------------------------------------------------void BSP_Lock( void );void BSP_Unlock( void );typedef struct{  unsigned char * buffer;  unsigned int capacity;  unsigned int pointer;  unsigned int count;} ring_buffer_t;ring_buffer_t *ring_buffer_create( unsigned int size );void ring_buffer_delete( ring_buffer_t *ring_buffer );void ring_buffer_init( ring_buffer_t *ring_buffer, unsigned char * buffer,  unsigned int capacity );void ring_buffer_clear( ring_buffer_t *ring_buffer );unsigned int ring_buffer_readable( ring_buffer_t *ring_buffer );unsigned int ring_buffer_writable( ring_buffer_t *ring_buffer );void ring_buffer_flush( ring_buffer_t *ring_buffer, unsigned int bytes );unsigned int ring_buffer_read( ring_buffer_t *ring_buffer, unsigned char *data,  unsigned int length );unsigned int ring_buffer_write( ring_buffer_t *ring_buffer,  const unsigned char *data, unsigned int length );unsigned int ring_buffer_full( ring_buffer_t *ring_buffer );unsigned int ring_buffer_empty( ring_buffer_t *ring_buffer );#endif /* __RING_BUFFER_H__ */

#include "ring_buffer.h"#include 
     
      #include 
      
       unsigned int ring_buffer_readable( ring_buffer_t *ring_buffer ){  return ring_buffer->count;}unsigned int ring_buffer_writable( ring_buffer_t *ring_buffer ){  return ring_buffer->capacity - ring_buffer->count;}unsigned int ring_buffer_full( ring_buffer_t *ring_buffer ){  return ring_buffer->count == ring_buffer->capacity;}unsigned int ring_buffer_empty( ring_buffer_t *ring_buffer ){  return ring_buffer->count == 0;}unsigned int ring_buffer_read( ring_buffer_t *ring_buffer, unsigned char *data,  unsigned int length ){  unsigned int buffer_readable = ring_buffer_readable( ring_buffer );  unsigned int bytes_read = length;  if ( bytes_read > buffer_readable )    bytes_read = buffer_readable;  if ( bytes_read == 0 )    return 0;  // -----------RRRRRRRRRRRR  if ( ring_buffer->pointer + bytes_read <= ring_buffer->capacity )    memcpy( data, ring_buffer->buffer + ring_buffer->pointer, bytes_read );  else // RRRRRR--------------RRRRR  {    unsigned int upper = ring_buffer->capacity - ring_buffer->pointer;    unsigned int lower = bytes_read - upper;    memcpy( data, ring_buffer->buffer + ring_buffer->pointer, upper );    memcpy( data + upper, ring_buffer->buffer, lower );  }  BSP_Lock( );  ring_buffer->pointer = ( ring_buffer->pointer + bytes_read )    % ring_buffer->capacity;  ring_buffer->count -= bytes_read;  BSP_Unlock( );  return bytes_read;}unsigned int ring_buffer_write( ring_buffer_t *ring_buffer,  const unsigned char *data, unsigned int length ){  unsigned int bytes_written = length;  unsigned int buffer_writable = ring_buffer_writable( ring_buffer );  if ( bytes_written > buffer_writable )    bytes_written = buffer_writable;  if ( bytes_written == 0 )    return 0;  unsigned int write_position = ( ring_buffer->pointer + ring_buffer->count )    % ring_buffer->capacity;  // --------WWWWWWWW---  if ( write_position + bytes_written <= ring_buffer->capacity )    memcpy( ring_buffer->buffer + write_position, data, bytes_written );  else  // WWWWWWW-------WWWW  {    unsigned int upper = ring_buffer->capacity - write_position;    unsigned int lower = bytes_written - upper;    memcpy( ring_buffer->buffer + write_position, data, upper );    memcpy( ring_buffer->buffer, data + upper, lower );  }  BSP_Lock( );  ring_buffer->count += bytes_written;  BSP_Unlock( );  return bytes_written;}void ring_buffer_flush( ring_buffer_t *ring_buffer, unsigned int length ){  // we can't flush more bytes than there are  BSP_Lock( );  if ( length > (unsigned int) ring_buffer->count )    length = ring_buffer->count;  ring_buffer->count -= length;  ring_buffer->pointer = ( ring_buffer->pointer + length );  ring_buffer->pointer %= ring_buffer->capacity;  BSP_Unlock( );}void ring_buffer_clear( ring_buffer_t *ring_buffer ){  BSP_Lock( );  ring_buffer->count = 0;  ring_buffer->pointer = 0;  BSP_Unlock( );}void ring_buffer_init( ring_buffer_t *ring_buffer, unsigned char * buffer,  unsigned int capacity ){  ring_buffer->buffer = buffer;  ring_buffer->capacity = capacity;  ring_buffer_clear( ring_buffer );}ring_buffer_t * ring_buffer_create( unsigned int size ){  void * p = malloc( sizeof(ring_buffer_t) + size );  ring_buffer_t *ring_buffer = (ring_buffer_t *) p;  if ( ring_buffer == NULL )    return NULL;  ring_buffer->capacity = size;  ring_buffer_clear( ring_buffer );  return ring_buffer;}void ring_buffer_delete( ring_buffer_t *ring_buffer ){  free( ring_buffer );}