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/*
* FreeRTOS+TCP 191100 experimental
* Copyright (C) 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* 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.
*
* http://aws.amazon.com/freertos
* http://www.FreeRTOS.org
*/
/*
* FreeRTOS_Stream_Buffer.h
*
* A cicular character buffer
* An implementation of a circular buffer without a length field
* If LENGTH defines the size of the buffer, a maximum of (LENGT-1) bytes can be stored
* In order to add or read data from the buffer, memcpy() will be called at most 2 times
*/
#ifndef FREERTOS_STREAM_BUFFER_H
#define FREERTOS_STREAM_BUFFER_H
#ifdef __cplusplus
extern "C" {
#endif
typedef struct xSTREAM_BUFFER {
volatile size_t uxTail; /* next item to read */
volatile size_t uxMid; /* iterator within the valid items */
volatile size_t uxHead; /* next position store a new item */
volatile size_t uxFront; /* iterator within the free space */
size_t LENGTH; /* const value: number of reserved elements */
uint8_t ucArray[ sizeof( size_t ) ];
} StreamBuffer_t;
static portINLINE void vStreamBufferClear( StreamBuffer_t *pxBuffer );
static portINLINE void vStreamBufferClear( StreamBuffer_t *pxBuffer )
{
/* Make the circular buffer empty */
pxBuffer->uxHead = 0u;
pxBuffer->uxTail = 0u;
pxBuffer->uxFront = 0u;
pxBuffer->uxMid = 0u;
}
/*-----------------------------------------------------------*/
static portINLINE size_t uxStreamBufferSpace( const StreamBuffer_t *pxBuffer, const size_t uxLower, const size_t uxUpper );
static portINLINE size_t uxStreamBufferSpace( const StreamBuffer_t *pxBuffer, const size_t uxLower, const size_t uxUpper )
{
/* Returns the space between uxLower and uxUpper, which equals to the distance minus 1 */
size_t uxCount;
uxCount = pxBuffer->LENGTH + uxUpper - uxLower - 1u;
if( uxCount >= pxBuffer->LENGTH )
{
uxCount -= pxBuffer->LENGTH;
}
return uxCount;
}
/*-----------------------------------------------------------*/
static portINLINE size_t uxStreamBufferDistance( const StreamBuffer_t *pxBuffer, const size_t uxLower, const size_t uxUpper );
static portINLINE size_t uxStreamBufferDistance( const StreamBuffer_t *pxBuffer, const size_t uxLower, const size_t uxUpper )
{
/* Returns the distance between uxLower and uxUpper */
size_t uxCount;
uxCount = pxBuffer->LENGTH + uxUpper - uxLower;
if ( uxCount >= pxBuffer->LENGTH )
{
uxCount -= pxBuffer->LENGTH;
}
return uxCount;
}
/*-----------------------------------------------------------*/
static portINLINE size_t uxStreamBufferGetSpace( const StreamBuffer_t *pxBuffer );
static portINLINE size_t uxStreamBufferGetSpace( const StreamBuffer_t *pxBuffer )
{
/* Returns the number of items which can still be added to uxHead
before hitting on uxTail */
size_t uxHead = pxBuffer->uxHead;
size_t uxTail = pxBuffer->uxTail;
return uxStreamBufferSpace( pxBuffer, uxHead, uxTail );
}
/*-----------------------------------------------------------*/
static portINLINE size_t uxStreamBufferFrontSpace( const StreamBuffer_t *pxBuffer );
static portINLINE size_t uxStreamBufferFrontSpace( const StreamBuffer_t *pxBuffer )
{
/* Distance between uxFront and uxTail
or the number of items which can still be added to uxFront,
before hitting on uxTail */
size_t uxFront = pxBuffer->uxFront;
size_t uxTail = pxBuffer->uxTail;
return uxStreamBufferSpace( pxBuffer, uxFront, uxTail );
}
/*-----------------------------------------------------------*/
static portINLINE size_t uxStreamBufferGetSize( const StreamBuffer_t *pxBuffer );
static portINLINE size_t uxStreamBufferGetSize( const StreamBuffer_t *pxBuffer )
{
/* Returns the number of items which can be read from uxTail
before reaching uxHead */
size_t uxHead = pxBuffer->uxHead;
size_t uxTail = pxBuffer->uxTail;
return uxStreamBufferDistance( pxBuffer, uxTail, uxHead );
}
/*-----------------------------------------------------------*/
static portINLINE size_t uxStreamBufferMidSpace( const StreamBuffer_t *pxBuffer );
static portINLINE size_t uxStreamBufferMidSpace( const StreamBuffer_t *pxBuffer )
{
/* Returns the distance between uxHead and uxMid */
size_t uxHead = pxBuffer->uxHead;
size_t uxMid = pxBuffer->uxMid;
return uxStreamBufferDistance( pxBuffer, uxMid, uxHead );
}
/*-----------------------------------------------------------*/
static portINLINE void vStreamBufferMoveMid( StreamBuffer_t *pxBuffer, size_t uxCount );
static portINLINE void vStreamBufferMoveMid( StreamBuffer_t *pxBuffer, size_t uxCount )
{
/* Increment uxMid, but no further than uxHead */
size_t uxSize = uxStreamBufferMidSpace( pxBuffer );
if( uxCount > uxSize )
{
uxCount = uxSize;
}
pxBuffer->uxMid += uxCount;
if( pxBuffer->uxMid >= pxBuffer->LENGTH )
{
pxBuffer->uxMid -= pxBuffer->LENGTH;
}
}
/*-----------------------------------------------------------*/
static portINLINE BaseType_t xStreamBufferIsEmpty( const StreamBuffer_t *pxBuffer );
static portINLINE BaseType_t xStreamBufferIsEmpty( const StreamBuffer_t *pxBuffer )
{
BaseType_t xReturn;
/* True if no item is available */
if( pxBuffer->uxHead == pxBuffer->uxTail )
{
xReturn = pdTRUE;
}
else
{
xReturn = pdFALSE;
}
return xReturn;
}
/*-----------------------------------------------------------*/
static portINLINE BaseType_t xStreamBufferIsFull( const StreamBuffer_t *pxBuffer );
static portINLINE BaseType_t xStreamBufferIsFull( const StreamBuffer_t *pxBuffer )
{
/* True if the available space equals zero. */
return ( BaseType_t ) ( uxStreamBufferGetSpace( pxBuffer ) == 0u );
}
/*-----------------------------------------------------------*/
static portINLINE BaseType_t xStreamBufferLessThenEqual( const StreamBuffer_t *pxBuffer, const size_t uxLeft, const size_t uxRight );
static portINLINE BaseType_t xStreamBufferLessThenEqual( const StreamBuffer_t *pxBuffer, const size_t uxLeft, const size_t uxRight )
{
BaseType_t xReturn;
size_t uxTail = pxBuffer->uxTail;
/* Returns true if ( uxLeft < uxRight ) */
if( ( uxLeft < uxTail ) ^ ( uxRight < uxTail ) )
{
if( uxRight < uxTail )
{
xReturn = pdTRUE;
}
else
{
xReturn = pdFALSE;
}
}
else
{
if( uxLeft <= uxRight )
{
xReturn = pdTRUE;
}
else
{
xReturn = pdFALSE;
}
}
return xReturn;
}
/*-----------------------------------------------------------*/
static portINLINE size_t uxStreamBufferGetPtr( StreamBuffer_t *pxBuffer, uint8_t **ppucData );
static portINLINE size_t uxStreamBufferGetPtr( StreamBuffer_t *pxBuffer, uint8_t **ppucData )
{
size_t uxNextTail = pxBuffer->uxTail;
size_t uxSize = uxStreamBufferGetSize( pxBuffer );
*ppucData = pxBuffer->ucArray + uxNextTail;
return FreeRTOS_min_uint32( uxSize, pxBuffer->LENGTH - uxNextTail );
}
/*
* Add bytes to a stream buffer.
*
* pxBuffer - The buffer to which the bytes will be added.
* uxOffset - If uxOffset > 0, data will be written at an offset from uxHead
* while uxHead will not be moved yet.
* pucData - A pointer to the data to be added.
* uxCount - The number of bytes to add.
*/
size_t uxStreamBufferAdd( StreamBuffer_t *pxBuffer, size_t uxOffset, const uint8_t *pucData, size_t uxCount );
/*
* Read bytes from a stream buffer.
*
* pxBuffer - The buffer from which the bytes will be read.
* uxOffset - Can be used to read data located at a certain offset from 'uxTail'.
* pucData - A pointer to the buffer into which data will be read.
* uxMaxCount - The number of bytes to read.
* xPeek - If set to pdTRUE the data will remain in the buffer.
*/
size_t uxStreamBufferGet( StreamBuffer_t *pxBuffer, size_t uxOffset, uint8_t *pucData, size_t uxMaxCount, BaseType_t xPeek );
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif /* !defined( FREERTOS_STREAM_BUFFER_H ) */
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