Fork of https://developer.mbed.org/users/bscott/code/STM32_USBDevice/
Fork of STM32_USBDevice by
USBSerial/CircBuffer.h
- Committer:
- Troels Nilsson
- Date:
- 2018-07-25
- Revision:
- 79:d28244984385
- Parent:
- 77:a98f786d05d4
File content as of revision 79:d28244984385:
/* Copyright (c) 2010-2011 mbed.org, MIT License * * 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. */ #ifndef CIRCBUFFER_H #define CIRCBUFFER_H template <class T, int Size> class CircBuffer { public: CircBuffer():write(0), read(0){} bool isFull() { return ((write + 1) % size == read); }; bool isEmpty() { return (read == write); }; void queue(T k) { if (isFull()) { read++; read %= size; } buf[write++] = k; write %= size; } uint16_t available() { return (write >= read) ? write - read : size - read + write; }; bool dequeue(T * c) { bool empty = isEmpty(); if (!empty) { *c = buf[read++]; read %= size; } return(!empty); }; void flush() { write = 0; read = 0; } // Queue a block of data of blockSize items void queue(const T *block, uint16_t blockSize) { if (blockSize >= size) { // Block is too big to fit in buffer, take the last size-1 items block = &block[blockSize - (size-1)]; blockSize = size-1; } if (write + blockSize > size) { // Need to wrap around std::memcpy(&buf[write], block, sizeof(T)*(size-write)); std::memcpy(buf, &block[size-write], sizeof(T)*(blockSize - (size-write))); } else { std::memcpy(&buf[write], block, sizeof(T)*blockSize); } // Update write position uint16_t wasFree = available() - size - 1; write = write + blockSize; write %= size; if (wasFree < blockSize) { // Update read position as well read = write + 1; read %= size; } } // Dequeue a block of data of at most blockSize items, writing them into block // Returns the number of items dequeued uint16_t dequeue(T *block, uint16_t blockSize) { if (isEmpty()) { return 0; } uint16_t isAvailable = available(); if (isAvailable < blockSize) { // Only return what we have blockSize = isAvailable; } if (read + blockSize > size) { // Need to wrap around std::memcpy(block, &buf[read], sizeof(T)*(size-read)); std::memcpy(&block[size-read], buf, sizeof(T)*(blockSize - (size-read))); } else { std::memcpy(block, &buf[read], sizeof(T)*blockSize); } // Update read position read = read + blockSize; read %= size; return blockSize; } private: volatile uint16_t write; volatile uint16_t read; static const int size = Size+1; //a modern optimizer should be able to remove this so it uses no ram. T buf[Size+1]; }; #endif