2 * FreeRTOS+TCP V2.0.7
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3 * Copyright (C) 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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5 * Permission is hereby granted, free of charge, to any person obtaining a copy of
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6 * this software and associated documentation files (the "Software"), to deal in
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7 * the Software without restriction, including without limitation the rights to
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8 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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9 * the Software, and to permit persons to whom the Software is furnished to do so,
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10 * subject to the following conditions:
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12 * The above copyright notice and this permission notice shall be included in all
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13 * copies or substantial portions of the Software.
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15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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17 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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18 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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19 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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20 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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22 * http://aws.amazon.com/freertos
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23 * http://www.FreeRTOS.org
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27 * FreeRTOS_Stream_Buffer.h
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29 * A cicular character buffer
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30 * An implementation of a circular buffer without a length field
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31 * If LENGTH defines the size of the buffer, a maximum of (LENGT-1) bytes can be stored
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32 * In order to add or read data from the buffer, memcpy() will be called at most 2 times
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35 #ifndef FREERTOS_STREAM_BUFFER_H
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36 #define FREERTOS_STREAM_BUFFER_H
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42 typedef struct xSTREAM_BUFFER {
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43 volatile size_t uxTail; /* next item to read */
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44 volatile size_t uxMid; /* iterator within the valid items */
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45 volatile size_t uxHead; /* next position store a new item */
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46 volatile size_t uxFront; /* iterator within the free space */
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47 size_t LENGTH; /* const value: number of reserved elements */
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48 uint8_t ucArray[ sizeof( size_t ) ];
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51 static portINLINE void vStreamBufferClear( StreamBuffer_t *pxBuffer );
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52 static portINLINE void vStreamBufferClear( StreamBuffer_t *pxBuffer )
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54 /* Make the circular buffer empty */
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55 pxBuffer->uxHead = 0u;
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56 pxBuffer->uxTail = 0u;
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57 pxBuffer->uxFront = 0u;
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58 pxBuffer->uxMid = 0u;
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60 /*-----------------------------------------------------------*/
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62 static portINLINE size_t uxStreamBufferSpace( const StreamBuffer_t *pxBuffer, const size_t uxLower, const size_t uxUpper );
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63 static portINLINE size_t uxStreamBufferSpace( const StreamBuffer_t *pxBuffer, const size_t uxLower, const size_t uxUpper )
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65 /* Returns the space between uxLower and uxUpper, which equals to the distance minus 1 */
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68 uxCount = pxBuffer->LENGTH + uxUpper - uxLower - 1u;
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69 if( uxCount >= pxBuffer->LENGTH )
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71 uxCount -= pxBuffer->LENGTH;
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76 /*-----------------------------------------------------------*/
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78 static portINLINE size_t uxStreamBufferDistance( const StreamBuffer_t *pxBuffer, const size_t uxLower, const size_t uxUpper );
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79 static portINLINE size_t uxStreamBufferDistance( const StreamBuffer_t *pxBuffer, const size_t uxLower, const size_t uxUpper )
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81 /* Returns the distance between uxLower and uxUpper */
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84 uxCount = pxBuffer->LENGTH + uxUpper - uxLower;
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85 if ( uxCount >= pxBuffer->LENGTH )
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87 uxCount -= pxBuffer->LENGTH;
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92 /*-----------------------------------------------------------*/
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94 static portINLINE size_t uxStreamBufferGetSpace( const StreamBuffer_t *pxBuffer );
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95 static portINLINE size_t uxStreamBufferGetSpace( const StreamBuffer_t *pxBuffer )
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97 /* Returns the number of items which can still be added to uxHead
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98 before hitting on uxTail */
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99 size_t uxHead = pxBuffer->uxHead;
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100 size_t uxTail = pxBuffer->uxTail;
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102 return uxStreamBufferSpace( pxBuffer, uxHead, uxTail );
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104 /*-----------------------------------------------------------*/
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106 static portINLINE size_t uxStreamBufferFrontSpace( const StreamBuffer_t *pxBuffer );
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107 static portINLINE size_t uxStreamBufferFrontSpace( const StreamBuffer_t *pxBuffer )
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109 /* Distance between uxFront and uxTail
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110 or the number of items which can still be added to uxFront,
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111 before hitting on uxTail */
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113 size_t uxFront = pxBuffer->uxFront;
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114 size_t uxTail = pxBuffer->uxTail;
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116 return uxStreamBufferSpace( pxBuffer, uxFront, uxTail );
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118 /*-----------------------------------------------------------*/
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120 static portINLINE size_t uxStreamBufferGetSize( const StreamBuffer_t *pxBuffer );
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121 static portINLINE size_t uxStreamBufferGetSize( const StreamBuffer_t *pxBuffer )
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123 /* Returns the number of items which can be read from uxTail
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124 before reaching uxHead */
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125 size_t uxHead = pxBuffer->uxHead;
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126 size_t uxTail = pxBuffer->uxTail;
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128 return uxStreamBufferDistance( pxBuffer, uxTail, uxHead );
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130 /*-----------------------------------------------------------*/
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132 static portINLINE size_t uxStreamBufferMidSpace( const StreamBuffer_t *pxBuffer );
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133 static portINLINE size_t uxStreamBufferMidSpace( const StreamBuffer_t *pxBuffer )
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135 /* Returns the distance between uxHead and uxMid */
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136 size_t uxHead = pxBuffer->uxHead;
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137 size_t uxMid = pxBuffer->uxMid;
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139 return uxStreamBufferDistance( pxBuffer, uxMid, uxHead );
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141 /*-----------------------------------------------------------*/
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143 static portINLINE void vStreamBufferMoveMid( StreamBuffer_t *pxBuffer, size_t uxCount );
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144 static portINLINE void vStreamBufferMoveMid( StreamBuffer_t *pxBuffer, size_t uxCount )
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146 /* Increment uxMid, but no further than uxHead */
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147 size_t uxSize = uxStreamBufferMidSpace( pxBuffer );
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149 if( uxCount > uxSize )
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153 pxBuffer->uxMid += uxCount;
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154 if( pxBuffer->uxMid >= pxBuffer->LENGTH )
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156 pxBuffer->uxMid -= pxBuffer->LENGTH;
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159 /*-----------------------------------------------------------*/
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160 static portINLINE BaseType_t xStreamBufferIsEmpty( const StreamBuffer_t *pxBuffer );
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161 static portINLINE BaseType_t xStreamBufferIsEmpty( const StreamBuffer_t *pxBuffer )
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163 BaseType_t xReturn;
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165 /* True if no item is available */
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166 if( pxBuffer->uxHead == pxBuffer->uxTail )
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176 /*-----------------------------------------------------------*/
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178 static portINLINE BaseType_t xStreamBufferIsFull( const StreamBuffer_t *pxBuffer );
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179 static portINLINE BaseType_t xStreamBufferIsFull( const StreamBuffer_t *pxBuffer )
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181 /* True if the available space equals zero. */
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182 return ( BaseType_t ) ( uxStreamBufferGetSpace( pxBuffer ) == 0u );
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184 /*-----------------------------------------------------------*/
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186 static portINLINE BaseType_t xStreamBufferLessThenEqual( const StreamBuffer_t *pxBuffer, const size_t uxLeft, const size_t uxRight );
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187 static portINLINE BaseType_t xStreamBufferLessThenEqual( const StreamBuffer_t *pxBuffer, const size_t uxLeft, const size_t uxRight )
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189 BaseType_t xReturn;
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190 size_t uxTail = pxBuffer->uxTail;
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192 /* Returns true if ( uxLeft < uxRight ) */
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193 if( ( uxLeft < uxTail ) ^ ( uxRight < uxTail ) )
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195 if( uxRight < uxTail )
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206 if( uxLeft <= uxRight )
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217 /*-----------------------------------------------------------*/
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219 static portINLINE size_t uxStreamBufferGetPtr( StreamBuffer_t *pxBuffer, uint8_t **ppucData );
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220 static portINLINE size_t uxStreamBufferGetPtr( StreamBuffer_t *pxBuffer, uint8_t **ppucData )
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222 size_t uxNextTail = pxBuffer->uxTail;
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223 size_t uxSize = uxStreamBufferGetSize( pxBuffer );
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225 *ppucData = pxBuffer->ucArray + uxNextTail;
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227 return FreeRTOS_min_uint32( uxSize, pxBuffer->LENGTH - uxNextTail );
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231 * Add bytes to a stream buffer.
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233 * pxBuffer - The buffer to which the bytes will be added.
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234 * uxOffset - If uxOffset > 0, data will be written at an offset from uxHead
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235 * while uxHead will not be moved yet.
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236 * pucData - A pointer to the data to be added.
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237 * uxCount - The number of bytes to add.
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239 size_t uxStreamBufferAdd( StreamBuffer_t *pxBuffer, size_t uxOffset, const uint8_t *pucData, size_t uxCount );
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242 * Read bytes from a stream buffer.
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244 * pxBuffer - The buffer from which the bytes will be read.
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245 * uxOffset - Can be used to read data located at a certain offset from 'uxTail'.
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246 * pucData - A pointer to the buffer into which data will be read.
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247 * uxMaxCount - The number of bytes to read.
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248 * xPeek - If set to pdTRUE the data will remain in the buffer.
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250 size_t uxStreamBufferGet( StreamBuffer_t *pxBuffer, size_t uxOffset, uint8_t *pucData, size_t uxMaxCount, BaseType_t xPeek );
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256 #endif /* !defined( FREERTOS_STREAM_BUFFER_H ) */
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