2 * FreeRTOS+TCP Labs Build 160919 (C) 2016 Real Time Engineers ltd.
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3 * Authors include Hein Tibosch and Richard Barry
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5 *******************************************************************************
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6 ***** NOTE ******* NOTE ******* NOTE ******* NOTE ******* NOTE ******* NOTE ***
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9 *** FREERTOS+TCP IS STILL IN THE LAB (mainly because the FTP and HTTP ***
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10 *** demos have a dependency on FreeRTOS+FAT, which is only in the Labs ***
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13 *** FreeRTOS+TCP is functional and has been used in commercial products ***
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14 *** for some time. Be aware however that we are still refining its ***
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15 *** design, the source code does not yet quite conform to the strict ***
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16 *** coding and style standards mandated by Real Time Engineers ltd., and ***
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17 *** the documentation and testing is not necessarily complete. ***
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19 *** PLEASE REPORT EXPERIENCES USING THE SUPPORT RESOURCES FOUND ON THE ***
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20 *** URL: http://www.FreeRTOS.org/contact Active early adopters may, at ***
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21 *** the sole discretion of Real Time Engineers Ltd., be offered versions ***
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22 *** under a license other than that described below. ***
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25 ***** NOTE ******* NOTE ******* NOTE ******* NOTE ******* NOTE ******* NOTE ***
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26 *******************************************************************************
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28 * FreeRTOS+TCP can be used under two different free open source licenses. The
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29 * license that applies is dependent on the processor on which FreeRTOS+TCP is
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30 * executed, as follows:
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32 * If FreeRTOS+TCP is executed on one of the processors listed under the Special
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33 * License Arrangements heading of the FreeRTOS+TCP license information web
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34 * page, then it can be used under the terms of the FreeRTOS Open Source
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35 * License. If FreeRTOS+TCP is used on any other processor, then it can be used
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36 * under the terms of the GNU General Public License V2. Links to the relevant
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39 * The FreeRTOS+TCP License Information Page: http://www.FreeRTOS.org/tcp_license
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40 * The FreeRTOS Open Source License: http://www.FreeRTOS.org/license
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41 * The GNU General Public License Version 2: http://www.FreeRTOS.org/gpl-2.0.txt
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43 * FreeRTOS+TCP is distributed in the hope that it will be useful. You cannot
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44 * use FreeRTOS+TCP unless you agree that you use the software 'as is'.
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45 * FreeRTOS+TCP is provided WITHOUT ANY WARRANTY; without even the implied
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46 * warranties of NON-INFRINGEMENT, MERCHANTABILITY or FITNESS FOR A PARTICULAR
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47 * PURPOSE. Real Time Engineers Ltd. disclaims all conditions and terms, be they
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48 * implied, expressed, or statutory.
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50 * 1 tab == 4 spaces!
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52 * http://www.FreeRTOS.org
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53 * http://www.FreeRTOS.org/plus
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54 * http://www.FreeRTOS.org/labs
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59 * FreeRTOS_Stream_Buffer.h
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61 * A cicular character buffer
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62 * An implementation of a circular buffer without a length field
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63 * If LENGTH defines the size of the buffer, a maximum of (LENGT-1) bytes can be stored
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64 * In order to add or read data from the buffer, memcpy() will be called at most 2 times
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67 #ifndef FREERTOS_STREAM_BUFFER_H
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68 #define FREERTOS_STREAM_BUFFER_H
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74 typedef struct xSTREAM_BUFFER {
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75 volatile size_t uxTail; /* next item to read */
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76 volatile size_t uxMid; /* iterator within the valid items */
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77 volatile size_t uxHead; /* next position store a new item */
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78 volatile size_t uxFront; /* iterator within the free space */
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79 size_t LENGTH; /* const value: number of reserved elements */
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80 uint8_t ucArray[ sizeof( size_t ) ];
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83 static portINLINE void vStreamBufferClear( StreamBuffer_t *pxBuffer );
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84 static portINLINE void vStreamBufferClear( StreamBuffer_t *pxBuffer )
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86 /* Make the circular buffer empty */
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87 pxBuffer->uxHead = 0u;
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88 pxBuffer->uxTail = 0u;
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89 pxBuffer->uxFront = 0u;
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90 pxBuffer->uxMid = 0u;
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92 /*-----------------------------------------------------------*/
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94 static portINLINE size_t uxStreamBufferSpace( const StreamBuffer_t *pxBuffer, const size_t uxLower, const size_t uxUpper );
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95 static portINLINE size_t uxStreamBufferSpace( const StreamBuffer_t *pxBuffer, const size_t uxLower, const size_t uxUpper )
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97 /* Returns the space between uxLower and uxUpper, which equals to the distance minus 1 */
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100 uxCount = pxBuffer->LENGTH + uxUpper - uxLower - 1u;
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101 if( uxCount >= pxBuffer->LENGTH )
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103 uxCount -= pxBuffer->LENGTH;
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108 /*-----------------------------------------------------------*/
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110 static portINLINE size_t uxStreamBufferDistance( const StreamBuffer_t *pxBuffer, const size_t uxLower, const size_t uxUpper );
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111 static portINLINE size_t uxStreamBufferDistance( const StreamBuffer_t *pxBuffer, const size_t uxLower, const size_t uxUpper )
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113 /* Returns the distance between uxLower and uxUpper */
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116 uxCount = pxBuffer->LENGTH + uxUpper - uxLower;
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117 if ( uxCount >= pxBuffer->LENGTH )
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119 uxCount -= pxBuffer->LENGTH;
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124 /*-----------------------------------------------------------*/
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126 static portINLINE size_t uxStreamBufferGetSpace( const StreamBuffer_t *pxBuffer );
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127 static portINLINE size_t uxStreamBufferGetSpace( const StreamBuffer_t *pxBuffer )
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129 /* Returns the number of items which can still be added to uxHead
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130 before hitting on uxTail */
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131 size_t uxHead = pxBuffer->uxHead;
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132 size_t uxTail = pxBuffer->uxTail;
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134 return uxStreamBufferSpace( pxBuffer, uxHead, uxTail );
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136 /*-----------------------------------------------------------*/
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138 static portINLINE size_t uxStreamBufferFrontSpace( const StreamBuffer_t *pxBuffer );
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139 static portINLINE size_t uxStreamBufferFrontSpace( const StreamBuffer_t *pxBuffer )
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141 /* Distance between uxFront and uxTail
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142 or the number of items which can still be added to uxFront,
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143 before hitting on uxTail */
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145 size_t uxFront = pxBuffer->uxFront;
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146 size_t uxTail = pxBuffer->uxTail;
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148 return uxStreamBufferSpace( pxBuffer, uxFront, uxTail );
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150 /*-----------------------------------------------------------*/
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152 static portINLINE size_t uxStreamBufferGetSize( const StreamBuffer_t *pxBuffer );
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153 static portINLINE size_t uxStreamBufferGetSize( const StreamBuffer_t *pxBuffer )
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155 /* Returns the number of items which can be read from uxTail
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156 before reaching uxHead */
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157 size_t uxHead = pxBuffer->uxHead;
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158 size_t uxTail = pxBuffer->uxTail;
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160 return uxStreamBufferDistance( pxBuffer, uxTail, uxHead );
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162 /*-----------------------------------------------------------*/
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164 static portINLINE size_t uxStreamBufferMidSpace( const StreamBuffer_t *pxBuffer );
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165 static portINLINE size_t uxStreamBufferMidSpace( const StreamBuffer_t *pxBuffer )
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167 /* Returns the distance between uxHead and uxMid */
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168 size_t uxHead = pxBuffer->uxHead;
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169 size_t uxMid = pxBuffer->uxMid;
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171 return uxStreamBufferDistance( pxBuffer, uxMid, uxHead );
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173 /*-----------------------------------------------------------*/
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175 static portINLINE void vStreamBufferMoveMid( StreamBuffer_t *pxBuffer, size_t uxCount );
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176 static portINLINE void vStreamBufferMoveMid( StreamBuffer_t *pxBuffer, size_t uxCount )
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178 /* Increment uxMid, but no further than uxHead */
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179 size_t uxSize = uxStreamBufferMidSpace( pxBuffer );
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181 if( uxCount > uxSize )
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185 pxBuffer->uxMid += uxCount;
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186 if( pxBuffer->uxMid >= pxBuffer->LENGTH )
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188 pxBuffer->uxMid -= pxBuffer->LENGTH;
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191 /*-----------------------------------------------------------*/
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192 static portINLINE BaseType_t xStreamBufferIsEmpty( const StreamBuffer_t *pxBuffer );
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193 static portINLINE BaseType_t xStreamBufferIsEmpty( const StreamBuffer_t *pxBuffer )
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195 BaseType_t xReturn;
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197 /* True if no item is available */
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198 if( pxBuffer->uxHead == pxBuffer->uxTail )
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208 /*-----------------------------------------------------------*/
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210 static portINLINE BaseType_t xStreamBufferIsFull( const StreamBuffer_t *pxBuffer );
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211 static portINLINE BaseType_t xStreamBufferIsFull( const StreamBuffer_t *pxBuffer )
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213 /* True if the available space equals zero. */
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214 return ( BaseType_t ) ( uxStreamBufferGetSpace( pxBuffer ) == 0u );
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216 /*-----------------------------------------------------------*/
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218 static portINLINE BaseType_t xStreamBufferLessThenEqual( const StreamBuffer_t *pxBuffer, const size_t uxLeft, const size_t uxRight );
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219 static portINLINE BaseType_t xStreamBufferLessThenEqual( const StreamBuffer_t *pxBuffer, const size_t uxLeft, const size_t uxRight )
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221 BaseType_t xReturn;
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222 size_t uxTail = pxBuffer->uxTail;
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224 /* Returns true if ( uxLeft < uxRight ) */
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225 if( ( uxLeft < uxTail ) ^ ( uxRight < uxTail ) )
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227 if( uxRight < uxTail )
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238 if( uxLeft <= uxRight )
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249 /*-----------------------------------------------------------*/
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251 static portINLINE size_t uxStreamBufferGetPtr( StreamBuffer_t *pxBuffer, uint8_t **ppucData );
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252 static portINLINE size_t uxStreamBufferGetPtr( StreamBuffer_t *pxBuffer, uint8_t **ppucData )
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254 size_t uxNextTail = pxBuffer->uxTail;
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255 size_t uxSize = uxStreamBufferGetSize( pxBuffer );
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257 *ppucData = pxBuffer->ucArray + uxNextTail;
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259 return FreeRTOS_min_uint32( uxSize, pxBuffer->LENGTH - uxNextTail );
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263 * Add bytes to a stream buffer.
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265 * pxBuffer - The buffer to which the bytes will be added.
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266 * uxOffset - If uxOffset > 0, data will be written at an offset from uxHead
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267 * while uxHead will not be moved yet.
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268 * pucData - A pointer to the data to be added.
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269 * uxCount - The number of bytes to add.
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271 size_t uxStreamBufferAdd( StreamBuffer_t *pxBuffer, size_t uxOffset, const uint8_t *pucData, size_t uxCount );
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274 * Read bytes from a stream buffer.
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276 * pxBuffer - The buffer from which the bytes will be read.
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277 * uxOffset - Can be used to read data located at a certain offset from 'uxTail'.
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278 * pucData - A pointer to the buffer into which data will be read.
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279 * uxMaxCount - The number of bytes to read.
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280 * xPeek - If set to pdTRUE the data will remain in the buffer.
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282 size_t uxStreamBufferGet( StreamBuffer_t *pxBuffer, size_t uxOffset, uint8_t *pucData, size_t uxMaxCount, BaseType_t xPeek );
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288 #endif /* !defined( FREERTOS_STREAM_BUFFER_H ) */
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