#ifndef ucoo_utils_fifo_hh #define ucoo_utils_fifo_hh // ucoolib - Microcontroller object oriented library. {{{ // // Copyright (C) 2012 Nicolas Schodet // // 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. // // }}} #include "ucoo/common.hh" namespace ucoo { /// First In First Out container. It is implemented as a circular buffer, /// providing thread safety if the reader and the writer are in separated /// threads. /// /// This is a rather low level container used to implement ucoolib features. template class Fifo { public: /// Constructor, initialise an empty FIFO. Fifo (); /// Test whether the FIFO is empty. bool empty () const { return head_ == tail_; } /// Test whether the FIFO is full. bool full () const { return head_ == next (tail_); } /// Return a reference to top (next to be popped) element, do not do that /// if FIFO is empty! T &top (); /// Remove an element, do not do that if FIFO is empty! T pop (); /// Add an element, do not do that if FIFO is full! void push (const T &e); /// Pop up to COUNT elements and store them in BUF. Return the number of /// read elements. int read (T *buf, int count); /// Read up to COUNT elements and store them in BUF. Return the number of /// read elements. Do not pop read elements. int read_peek (T *buf, int count); /// Drop COUNT elements, do not do that if COUNT elements are not present! void drop (int count); /// Push up to COUNT elements from BUF. Return the number of written /// elements. int write (const T *buf, int count); /// Return the number of available elements to be read. int poll (); private: /// Return next index, use unsigned operation for optimisation. int next (int index) const { return (static_cast (index) + 1) % (size + 1); } private: /// Index of the next element to pop, always incremented. int_atomic_t head_; /// Index of the next free space where to put a pushed element, also /// always incremented. int_atomic_t tail_; /// Memory to store elements. T buffer_[size + 1]; }; } // namespace ucoo #include "fifo.tcc" #endif // ucoo_utils_fifo_hh