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Adafruit_FIFO.cpp@0:39b7f3158ebe, 2018-04-05 (annotated)
- Committer:
- wninghj
- Date:
- Thu Apr 05 21:26:10 2018 +0000
- Revision:
- 0:39b7f3158ebe
TEAM12 DJ;
Who changed what in which revision?
| User | Revision | Line number | New contents of line | 
|---|---|---|---|
| wninghj | 0:39b7f3158ebe | 1 | /**************************************************************************/ | 
| wninghj | 0:39b7f3158ebe | 2 | /*! | 
| wninghj | 0:39b7f3158ebe | 3 | @file Adafruit_FIFO.cpp | 
| wninghj | 0:39b7f3158ebe | 4 | @author hathach | 
| wninghj | 0:39b7f3158ebe | 5 | |
| wninghj | 0:39b7f3158ebe | 6 | @section LICENSE | 
| wninghj | 0:39b7f3158ebe | 7 | |
| wninghj | 0:39b7f3158ebe | 8 | Software License Agreement (BSD License) | 
| wninghj | 0:39b7f3158ebe | 9 | |
| wninghj | 0:39b7f3158ebe | 10 | Copyright (c) 2015, Adafruit Industries (adafruit.com) | 
| wninghj | 0:39b7f3158ebe | 11 | All rights reserved. | 
| wninghj | 0:39b7f3158ebe | 12 | |
| wninghj | 0:39b7f3158ebe | 13 | Redistribution and use in source and binary forms, with or without | 
| wninghj | 0:39b7f3158ebe | 14 | modification, are permitted provided that the following conditions are met: | 
| wninghj | 0:39b7f3158ebe | 15 | 1. Redistributions of source code must retain the above copyright | 
| wninghj | 0:39b7f3158ebe | 16 | notice, this list of conditions and the following disclaimer. | 
| wninghj | 0:39b7f3158ebe | 17 | 2. Redistributions in binary form must reproduce the above copyright | 
| wninghj | 0:39b7f3158ebe | 18 | notice, this list of conditions and the following disclaimer in the | 
| wninghj | 0:39b7f3158ebe | 19 | documentation and/or other materials provided with the distribution. | 
| wninghj | 0:39b7f3158ebe | 20 | 3. Neither the name of the copyright holders nor the | 
| wninghj | 0:39b7f3158ebe | 21 | names of its contributors may be used to endorse or promote products | 
| wninghj | 0:39b7f3158ebe | 22 | derived from this software without specific prior written permission. | 
| wninghj | 0:39b7f3158ebe | 23 | |
| wninghj | 0:39b7f3158ebe | 24 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ''AS IS'' AND ANY | 
| wninghj | 0:39b7f3158ebe | 25 | EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED | 
| wninghj | 0:39b7f3158ebe | 26 | WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE | 
| wninghj | 0:39b7f3158ebe | 27 | DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY | 
| wninghj | 0:39b7f3158ebe | 28 | DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES | 
| wninghj | 0:39b7f3158ebe | 29 | (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | 
| wninghj | 0:39b7f3158ebe | 30 | LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND | 
| wninghj | 0:39b7f3158ebe | 31 | ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | 
| wninghj | 0:39b7f3158ebe | 32 | (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS | 
| wninghj | 0:39b7f3158ebe | 33 | SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | 
| wninghj | 0:39b7f3158ebe | 34 | */ | 
| wninghj | 0:39b7f3158ebe | 35 | /**************************************************************************/ | 
| wninghj | 0:39b7f3158ebe | 36 | |
| wninghj | 0:39b7f3158ebe | 37 | #include "Adafruit_FIFO.h" | 
| wninghj | 0:39b7f3158ebe | 38 | #include <string.h> | 
| wninghj | 0:39b7f3158ebe | 39 | |
| wninghj | 0:39b7f3158ebe | 40 | /******************************************************************************/ | 
| wninghj | 0:39b7f3158ebe | 41 | /*! | 
| wninghj | 0:39b7f3158ebe | 42 | @brief Constructor | 
| wninghj | 0:39b7f3158ebe | 43 | |
| wninghj | 0:39b7f3158ebe | 44 | @param[in] buffer | 
| wninghj | 0:39b7f3158ebe | 45 | Memory location to store data | 
| wninghj | 0:39b7f3158ebe | 46 | @param[in] depth | 
| wninghj | 0:39b7f3158ebe | 47 | Maximum number of items can be hold in buffer | 
| wninghj | 0:39b7f3158ebe | 48 | @param[in] item_size | 
| wninghj | 0:39b7f3158ebe | 49 | Number of bytes of each item | 
| wninghj | 0:39b7f3158ebe | 50 | @param[in] overwrite | 
| wninghj | 0:39b7f3158ebe | 51 | Should the buffer is overwitten to the first item when it is full | 
| wninghj | 0:39b7f3158ebe | 52 | */ | 
| wninghj | 0:39b7f3158ebe | 53 | /******************************************************************************/ | 
| wninghj | 0:39b7f3158ebe | 54 | Adafruit_FIFO::Adafruit_FIFO(void* buffer, uint16_t depth, uint8_t item_size, bool overwrite) | 
| wninghj | 0:39b7f3158ebe | 55 | { | 
| wninghj | 0:39b7f3158ebe | 56 | m_buffer = (uint8_t*) buffer; | 
| wninghj | 0:39b7f3158ebe | 57 | m_depth = depth; | 
| wninghj | 0:39b7f3158ebe | 58 | m_item_size = item_size; | 
| wninghj | 0:39b7f3158ebe | 59 | m_overwritable = overwrite; | 
| wninghj | 0:39b7f3158ebe | 60 | |
| wninghj | 0:39b7f3158ebe | 61 | m_count = m_wr_idx = m_rd_idx = 0; | 
| wninghj | 0:39b7f3158ebe | 62 | } | 
| wninghj | 0:39b7f3158ebe | 63 | |
| wninghj | 0:39b7f3158ebe | 64 | /******************************************************************************/ | 
| wninghj | 0:39b7f3158ebe | 65 | /*! | 
| wninghj | 0:39b7f3158ebe | 66 | @brief Clear the FIFO | 
| wninghj | 0:39b7f3158ebe | 67 | */ | 
| wninghj | 0:39b7f3158ebe | 68 | /******************************************************************************/ | 
| wninghj | 0:39b7f3158ebe | 69 | void Adafruit_FIFO::clear(void) | 
| wninghj | 0:39b7f3158ebe | 70 | { | 
| wninghj | 0:39b7f3158ebe | 71 | m_rd_idx = m_wr_idx = m_count = 0; | 
| wninghj | 0:39b7f3158ebe | 72 | } | 
| wninghj | 0:39b7f3158ebe | 73 | |
| wninghj | 0:39b7f3158ebe | 74 | /******************************************************************************/ | 
| wninghj | 0:39b7f3158ebe | 75 | /*! | 
| wninghj | 0:39b7f3158ebe | 76 | @brief Write an item to the FIFO | 
| wninghj | 0:39b7f3158ebe | 77 | |
| wninghj | 0:39b7f3158ebe | 78 | @param[in] item | 
| wninghj | 0:39b7f3158ebe | 79 | Memory address of the item | 
| wninghj | 0:39b7f3158ebe | 80 | */ | 
| wninghj | 0:39b7f3158ebe | 81 | /******************************************************************************/ | 
| wninghj | 0:39b7f3158ebe | 82 | bool Adafruit_FIFO::write(void const* item) | 
| wninghj | 0:39b7f3158ebe | 83 | { | 
| wninghj | 0:39b7f3158ebe | 84 | if ( full() && !m_overwritable ) return false; | 
| wninghj | 0:39b7f3158ebe | 85 | |
| wninghj | 0:39b7f3158ebe | 86 | memcpy( m_buffer + (m_wr_idx * m_item_size), | 
| wninghj | 0:39b7f3158ebe | 87 | item, | 
| wninghj | 0:39b7f3158ebe | 88 | m_item_size); | 
| wninghj | 0:39b7f3158ebe | 89 | |
| wninghj | 0:39b7f3158ebe | 90 | m_wr_idx = (m_wr_idx + 1) % m_depth; | 
| wninghj | 0:39b7f3158ebe | 91 | |
| wninghj | 0:39b7f3158ebe | 92 | if ( full() ) | 
| wninghj | 0:39b7f3158ebe | 93 | { | 
| wninghj | 0:39b7f3158ebe | 94 | m_rd_idx = m_wr_idx; // keep the full state (rd == wr && len = size) | 
| wninghj | 0:39b7f3158ebe | 95 | } | 
| wninghj | 0:39b7f3158ebe | 96 | else | 
| wninghj | 0:39b7f3158ebe | 97 | { | 
| wninghj | 0:39b7f3158ebe | 98 | m_count++; | 
| wninghj | 0:39b7f3158ebe | 99 | } | 
| wninghj | 0:39b7f3158ebe | 100 | |
| wninghj | 0:39b7f3158ebe | 101 | return true; | 
| wninghj | 0:39b7f3158ebe | 102 | } | 
| wninghj | 0:39b7f3158ebe | 103 | |
| wninghj | 0:39b7f3158ebe | 104 | /******************************************************************************/ | 
| wninghj | 0:39b7f3158ebe | 105 | /*! | 
| wninghj | 0:39b7f3158ebe | 106 | @brief Write array of items to the FIFO | 
| wninghj | 0:39b7f3158ebe | 107 | |
| wninghj | 0:39b7f3158ebe | 108 | @param[in] data | 
| wninghj | 0:39b7f3158ebe | 109 | Memory address of the item's array | 
| wninghj | 0:39b7f3158ebe | 110 | @param[in] n | 
| wninghj | 0:39b7f3158ebe | 111 | Number of items to write | 
| wninghj | 0:39b7f3158ebe | 112 | |
| wninghj | 0:39b7f3158ebe | 113 | @return Number of written items | 
| wninghj | 0:39b7f3158ebe | 114 | */ | 
| wninghj | 0:39b7f3158ebe | 115 | /******************************************************************************/ | 
| wninghj | 0:39b7f3158ebe | 116 | uint16_t Adafruit_FIFO::write_n(void const * data, uint16_t n) | 
| wninghj | 0:39b7f3158ebe | 117 | { | 
| wninghj | 0:39b7f3158ebe | 118 | if ( n == 0 ) return 0; | 
| wninghj | 0:39b7f3158ebe | 119 | |
| wninghj | 0:39b7f3158ebe | 120 | uint8_t* buf = (uint8_t*) data; | 
| wninghj | 0:39b7f3158ebe | 121 | |
| wninghj | 0:39b7f3158ebe | 122 | uint16_t len = 0; | 
| wninghj | 0:39b7f3158ebe | 123 | while( (len < n) && write(buf) ) | 
| wninghj | 0:39b7f3158ebe | 124 | { | 
| wninghj | 0:39b7f3158ebe | 125 | len++; | 
| wninghj | 0:39b7f3158ebe | 126 | buf += m_item_size; | 
| wninghj | 0:39b7f3158ebe | 127 | } | 
| wninghj | 0:39b7f3158ebe | 128 | |
| wninghj | 0:39b7f3158ebe | 129 | return len; | 
| wninghj | 0:39b7f3158ebe | 130 | } | 
| wninghj | 0:39b7f3158ebe | 131 | |
| wninghj | 0:39b7f3158ebe | 132 | /******************************************************************************/ | 
| wninghj | 0:39b7f3158ebe | 133 | /*! | 
| wninghj | 0:39b7f3158ebe | 134 | @brief Read an item from FIFO | 
| wninghj | 0:39b7f3158ebe | 135 | |
| wninghj | 0:39b7f3158ebe | 136 | @param[in] buffer | 
| wninghj | 0:39b7f3158ebe | 137 | Memory address to store item | 
| wninghj | 0:39b7f3158ebe | 138 | */ | 
| wninghj | 0:39b7f3158ebe | 139 | /******************************************************************************/ | 
| wninghj | 0:39b7f3158ebe | 140 | bool Adafruit_FIFO::read(void* buffer) | 
| wninghj | 0:39b7f3158ebe | 141 | { | 
| wninghj | 0:39b7f3158ebe | 142 | if( empty() ) return false; | 
| wninghj | 0:39b7f3158ebe | 143 | |
| wninghj | 0:39b7f3158ebe | 144 | memcpy(buffer, | 
| wninghj | 0:39b7f3158ebe | 145 | m_buffer + (m_rd_idx * m_item_size), | 
| wninghj | 0:39b7f3158ebe | 146 | m_item_size); | 
| wninghj | 0:39b7f3158ebe | 147 | m_rd_idx = (m_rd_idx + 1) % m_depth; | 
| wninghj | 0:39b7f3158ebe | 148 | m_count--; | 
| wninghj | 0:39b7f3158ebe | 149 | |
| wninghj | 0:39b7f3158ebe | 150 | return true; | 
| wninghj | 0:39b7f3158ebe | 151 | } | 
| wninghj | 0:39b7f3158ebe | 152 | |
| wninghj | 0:39b7f3158ebe | 153 | /******************************************************************************/ | 
| wninghj | 0:39b7f3158ebe | 154 | /*! | 
| wninghj | 0:39b7f3158ebe | 155 | @brief Read multiple items to an array | 
| wninghj | 0:39b7f3158ebe | 156 | |
| wninghj | 0:39b7f3158ebe | 157 | @param[in] buffer | 
| wninghj | 0:39b7f3158ebe | 158 | Memory address of the item's array | 
| wninghj | 0:39b7f3158ebe | 159 | @param[in] n | 
| wninghj | 0:39b7f3158ebe | 160 | Number of items to read | 
| wninghj | 0:39b7f3158ebe | 161 | |
| wninghj | 0:39b7f3158ebe | 162 | @return Number of read items | 
| wninghj | 0:39b7f3158ebe | 163 | */ | 
| wninghj | 0:39b7f3158ebe | 164 | /******************************************************************************/ | 
| wninghj | 0:39b7f3158ebe | 165 | |
| wninghj | 0:39b7f3158ebe | 166 | uint16_t Adafruit_FIFO::read_n (void * buffer, uint16_t n) | 
| wninghj | 0:39b7f3158ebe | 167 | { | 
| wninghj | 0:39b7f3158ebe | 168 | if( n == 0 ) return 0; | 
| wninghj | 0:39b7f3158ebe | 169 | |
| wninghj | 0:39b7f3158ebe | 170 | uint8_t* buf = (uint8_t*) buffer; | 
| wninghj | 0:39b7f3158ebe | 171 | |
| wninghj | 0:39b7f3158ebe | 172 | uint16_t len = 0; | 
| wninghj | 0:39b7f3158ebe | 173 | while( (len < n) && read(buf) ) | 
| wninghj | 0:39b7f3158ebe | 174 | { | 
| wninghj | 0:39b7f3158ebe | 175 | len++; | 
| wninghj | 0:39b7f3158ebe | 176 | buf += m_item_size; | 
| wninghj | 0:39b7f3158ebe | 177 | } | 
| wninghj | 0:39b7f3158ebe | 178 | |
| wninghj | 0:39b7f3158ebe | 179 | return len; | 
| wninghj | 0:39b7f3158ebe | 180 | } | 
| wninghj | 0:39b7f3158ebe | 181 | |
| wninghj | 0:39b7f3158ebe | 182 | /******************************************************************************/ | 
| wninghj | 0:39b7f3158ebe | 183 | /*! | 
| wninghj | 0:39b7f3158ebe | 184 | @brief Read an item without removing it from the FIFO | 
| wninghj | 0:39b7f3158ebe | 185 | |
| wninghj | 0:39b7f3158ebe | 186 | @param[in] buffer | 
| wninghj | 0:39b7f3158ebe | 187 | Memory address to store item | 
| wninghj | 0:39b7f3158ebe | 188 | */ | 
| wninghj | 0:39b7f3158ebe | 189 | /******************************************************************************/ | 
| wninghj | 0:39b7f3158ebe | 190 | bool Adafruit_FIFO::peek(void* buffer) | 
| wninghj | 0:39b7f3158ebe | 191 | { | 
| wninghj | 0:39b7f3158ebe | 192 | if( empty() ) return false; | 
| wninghj | 0:39b7f3158ebe | 193 | |
| wninghj | 0:39b7f3158ebe | 194 | memcpy(buffer, | 
| wninghj | 0:39b7f3158ebe | 195 | m_buffer + (m_rd_idx * m_item_size), | 
| wninghj | 0:39b7f3158ebe | 196 | m_item_size); | 
| wninghj | 0:39b7f3158ebe | 197 | |
| wninghj | 0:39b7f3158ebe | 198 | return true; | 
| wninghj | 0:39b7f3158ebe | 199 | } | 
| wninghj | 0:39b7f3158ebe | 200 | |
| wninghj | 0:39b7f3158ebe | 201 | |
| wninghj | 0:39b7f3158ebe | 202 | /******************************************************************************/ | 
| wninghj | 0:39b7f3158ebe | 203 | /*! | 
| wninghj | 0:39b7f3158ebe | 204 | @brief Read an item without removing it from the FIFO at the specific index | 
| wninghj | 0:39b7f3158ebe | 205 | |
| wninghj | 0:39b7f3158ebe | 206 | @param[in] position | 
| wninghj | 0:39b7f3158ebe | 207 | Position to read from in the FIFO buffer | 
| wninghj | 0:39b7f3158ebe | 208 | |
| wninghj | 0:39b7f3158ebe | 209 | @param[in] buffer | 
| wninghj | 0:39b7f3158ebe | 210 | Memory address to store item | 
| wninghj | 0:39b7f3158ebe | 211 | */ | 
| wninghj | 0:39b7f3158ebe | 212 | /******************************************************************************/ | 
| wninghj | 0:39b7f3158ebe | 213 | bool Adafruit_FIFO::peekAt(uint16_t position, void * p_buffer) | 
| wninghj | 0:39b7f3158ebe | 214 | { | 
| wninghj | 0:39b7f3158ebe | 215 | if( empty() || (position >= m_count) ) return false; | 
| wninghj | 0:39b7f3158ebe | 216 | |
| wninghj | 0:39b7f3158ebe | 217 | uint16_t index = (m_rd_idx + position) % m_depth; // rd_idx is position=0 | 
| wninghj | 0:39b7f3158ebe | 218 | memcpy(p_buffer, | 
| wninghj | 0:39b7f3158ebe | 219 | m_buffer + (index * m_item_size), | 
| wninghj | 0:39b7f3158ebe | 220 | m_item_size); | 
| wninghj | 0:39b7f3158ebe | 221 | |
| wninghj | 0:39b7f3158ebe | 222 | return true; | 
| wninghj | 0:39b7f3158ebe | 223 | } | 
| wninghj | 0:39b7f3158ebe | 224 |