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/*
------------------------------------------------------------------------
COPYRIGHT (c) 2014.
On-Line Applications Research Corporation (OAR).
The license and distribution terms for this file may be
found in the file LICENSE in this distribution.
This software with is provided ``as is'' and with NO WARRANTY.
------------------------------------------------------------------------
RTEMS Performance Monitoring and Measurement Framework.
This is the Target Interface Command Line Interface. You need
start the RTEMS monitor.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems.h>
#include <rtems/score/assert.h>
#include "capture_buffer.h"
void * rtems_capture_buffer_allocate( rtems_capture_buffer_t* buffer, size_t size )
{
size_t end;
void *ptr;
if ( rtems_capture_buffer_is_full( buffer ) )
return NULL;
if ( (buffer->count + size) > buffer->end )
return NULL;
/*
* Determine if the end of free space is marked with
* the end of buffer space, or the head of allocated
* space.
*
* |...|head| freespace |tail| ...| end
*
* tail|.....|head| freespace| end
*
*/
if (buffer->tail > buffer->head) {
end = buffer->tail;
} else {
end = buffer->end;
}
/*
* Can we allocate it easily?
*/
if ((buffer->head + size) <= end) {
ptr = &buffer->buffer[ buffer->head ];
buffer->head += size;
buffer->count = buffer->count + size;
return ptr;
}
/*
* We have to consider wrapping around to the front of the buffer
*/
/* If there is not room at the end of the buffer */
/* and we have we already wrapped then we can't allocate */
if ( end == buffer->tail )
return NULL;
/* Is there no room at the front of the buffer */
if ( (buffer->tail < size ))
return NULL;
/* change the end pointer to the last used byte, so a read will wrap when out of data */
buffer->end = buffer->head;
/* now return the buffer */
ptr = buffer->buffer;
buffer->head = size;
buffer->count = buffer->count + size;
return ptr;
}
void *rtems_capture_buffer_free( rtems_capture_buffer_t* buffer, size_t size )
{
void *ptr;
size_t next;
size_t buff_size;
if (size == 0)
return NULL;
ptr = rtems_capture_buffer_peek(buffer, &buff_size);
next = buffer->tail + size;
/* Check if we are freeing space past the end of the buffer */
_Assert( ! rtems_capture_buffer_is_empty( buffer ) );
_Assert( !((buffer->tail > buffer->head) && (next > buffer->end)) );
_Assert( !((buffer->tail < buffer->head) && (next > buffer->head)) );
buffer->count = buffer->count - size;
if (next == buffer->end) {
buffer->end = buffer->size;
buffer->tail = 0;
} else {
buffer->tail = next;
}
return ptr;
}
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