Diff: Adafruit_FIFO.cpp

Revision:

0:39b7f3158ebe

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Adafruit_FIFO.cpp	Thu Apr 05 21:26:10 2018 +0000
@@ -0,0 +1,224 @@
+/**************************************************************************/
+/*!
+    @file     Adafruit_FIFO.cpp
+    @author   hathach
+
+    @section LICENSE
+
+    Software License Agreement (BSD License)
+
+    Copyright (c) 2015, Adafruit Industries (adafruit.com)
+    All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions are met:
+    1. Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in the
+    documentation and/or other materials provided with the distribution.
+    3. Neither the name of the copyright holders nor the
+    names of its contributors may be used to endorse or promote products
+    derived from this software without specific prior written permission.
+
+    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ''AS IS'' AND ANY
+    EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+    WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+    DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY
+    DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+    (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+    ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+/**************************************************************************/
+
+#include "Adafruit_FIFO.h"
+#include <string.h>
+
+/******************************************************************************/
+/*!
+    @brief  Constructor
+
+    @param[in] buffer
+               Memory location to store data
+    @param[in] depth
+               Maximum number of items can be hold in buffer
+    @param[in] item_size
+               Number of bytes of each item
+    @param[in] overwrite
+               Should the buffer is overwitten to the first item when it is full
+*/
+/******************************************************************************/
+Adafruit_FIFO::Adafruit_FIFO(void* buffer, uint16_t depth, uint8_t item_size, bool overwrite)
+{
+  m_buffer       = (uint8_t*) buffer;
+  m_depth        = depth;
+  m_item_size    = item_size;
+  m_overwritable = overwrite;
+
+  m_count = m_wr_idx = m_rd_idx = 0;
+}
+
+/******************************************************************************/
+/*!
+    @brief  Clear the FIFO
+*/
+/******************************************************************************/
+void Adafruit_FIFO::clear(void)
+{
+  m_rd_idx = m_wr_idx = m_count = 0;
+}
+
+/******************************************************************************/
+/*!
+    @brief  Write an item to the FIFO
+
+    @param[in] item
+               Memory address of the item
+*/
+/******************************************************************************/
+bool Adafruit_FIFO::write(void const* item)
+{
+  if ( full() && !m_overwritable ) return false;
+
+  memcpy( m_buffer + (m_wr_idx * m_item_size),
+          item,
+          m_item_size);
+
+  m_wr_idx = (m_wr_idx + 1) % m_depth;
+
+  if ( full() )
+  {
+    m_rd_idx = m_wr_idx; // keep the full state (rd == wr && len = size)
+  }
+  else
+  {
+    m_count++;
+  }
+
+  return true;
+}
+
+/******************************************************************************/
+/*!
+    @brief  Write array of items to the FIFO
+
+    @param[in] data
+               Memory address of the item's array
+    @param[in] n
+               Number of items to write
+
+    @return    Number of written items
+*/
+/******************************************************************************/
+uint16_t Adafruit_FIFO::write_n(void const * data, uint16_t n)
+{
+  if ( n == 0 ) return 0;
+
+  uint8_t* buf = (uint8_t*) data;
+
+  uint16_t len = 0;
+  while( (len < n) && write(buf) )
+  {
+    len++;
+    buf += m_item_size;
+  }
+
+  return len;
+}
+
+/******************************************************************************/
+/*!
+    @brief  Read an item from FIFO
+
+    @param[in] buffer
+               Memory address to store item
+*/
+/******************************************************************************/
+bool Adafruit_FIFO::read(void* buffer)
+{
+  if( empty() ) return false;
+
+  memcpy(buffer,
+         m_buffer + (m_rd_idx * m_item_size),
+         m_item_size);
+  m_rd_idx = (m_rd_idx + 1) % m_depth;
+  m_count--;
+
+  return true;
+}
+
+/******************************************************************************/
+/*!
+    @brief  Read multiple items to an array
+
+    @param[in] buffer
+               Memory address of the item's array
+    @param[in] n
+               Number of items to read
+
+    @return    Number of read items
+*/
+/******************************************************************************/
+
+uint16_t Adafruit_FIFO::read_n (void * buffer, uint16_t n)
+{
+  if( n == 0 ) return 0;
+
+  uint8_t* buf = (uint8_t*) buffer;
+
+  uint16_t len = 0;
+  while( (len < n) && read(buf) )
+  {
+    len++;
+    buf += m_item_size;
+  }
+
+  return len;
+}
+
+/******************************************************************************/
+/*!
+    @brief  Read an item without removing it from the FIFO
+
+    @param[in] buffer
+               Memory address to store item
+*/
+/******************************************************************************/
+bool Adafruit_FIFO::peek(void* buffer)
+{
+  if( empty() ) return false;
+
+  memcpy(buffer,
+         m_buffer + (m_rd_idx * m_item_size),
+         m_item_size);
+
+  return true;
+}
+
+
+/******************************************************************************/
+/*!
+    @brief  Read an item without removing it from the FIFO at the specific index
+
+    @param[in] position
+               Position to read from in the FIFO buffer
+
+    @param[in] buffer
+               Memory address to store item
+*/
+/******************************************************************************/
+bool Adafruit_FIFO::peekAt(uint16_t position, void * p_buffer)
+{
+  if( empty() || (position >= m_count) ) return false;
+
+  uint16_t index = (m_rd_idx + position) % m_depth; // rd_idx is position=0
+  memcpy(p_buffer,
+         m_buffer + (index * m_item_size),
+         m_item_size);
+
+  return true;
+}
+