| /* |
| * Copyright (c) 2015 ARM Limited |
| * All rights reserved |
| * |
| * The license below extends only to copyright in the software and shall |
| * not be construed as granting a license to any other intellectual |
| * property including but not limited to intellectual property relating |
| * to a hardware implementation of the functionality of the software |
| * licensed hereunder. You may use the software subject to the license |
| * terms below provided that you ensure that this notice is replicated |
| * unmodified and in its entirety in all distributions of the software, |
| * modified or unmodified, in source code or in binary form. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are |
| * met: redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer; |
| * 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; |
| * 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 AND CONTRIBUTORS |
| * "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 |
| * OWNER OR CONTRIBUTORS 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. |
| * |
| * Authors: Andreas Sandberg |
| */ |
| |
| #ifndef __BASE_CIRCLEBUF_HH__ |
| #define __BASE_CIRCLEBUF_HH__ |
| |
| #include <algorithm> |
| #include <cassert> |
| #include <vector> |
| |
| #include "base/misc.hh" |
| #include "sim/serialize.hh" |
| |
| /** |
| * Circular buffer backed by a vector |
| * |
| * The data in the cricular buffer is stored in a standard |
| * vector. _start designates the first element in the buffer and _stop |
| * points to the last element + 1 (i.e., the position of the next |
| * insertion). The _stop index may be outside the range of the backing |
| * store, which means that the actual index must be calculated as |
| * _stop % capacity. |
| * |
| * Invariants: |
| * <ul> |
| * <li>_start <= _stop |
| * <li>_start < capacity |
| * <li>_stop < 2 * capacity |
| * </ul> |
| */ |
| template<typename T> |
| class CircleBuf |
| { |
| public: |
| typedef T value_type; |
| |
| public: |
| explicit CircleBuf(size_t size) |
| : buf(size), _start(0), _stop(0) {} |
| |
| /** Is the buffer empty? */ |
| bool empty() const { return _stop == _start; } |
| /** |
| * Return the maximum number of elements that can be stored in |
| * the buffer at any one time. |
| */ |
| size_t capacity() const { return buf.size(); } |
| /** Return the number of elements stored in the buffer. */ |
| size_t size() const { return _stop - _start; } |
| |
| /** |
| * Remove all the elements in the buffer. |
| * |
| * Note: This does not actually remove elements from the backing |
| * store. |
| */ |
| void flush() { |
| _start = 0; |
| _stop = 0; |
| } |
| |
| /** |
| * Copy buffer contents without advancing the read pointer |
| * |
| * @param out Output iterator/pointer |
| * @param len Number of elements to copy |
| */ |
| template <class OutputIterator> |
| void peek(OutputIterator out, size_t len) const { |
| peek(out, 0, len); |
| } |
| |
| /** |
| * Copy buffer contents without advancing the read pointer |
| * |
| * @param out Output iterator/pointer |
| * @param offset Offset into the ring buffer |
| * @param len Number of elements to copy |
| */ |
| template <class OutputIterator> |
| void peek(OutputIterator out, off_t offset, size_t len) const { |
| panic_if(offset + len > size(), |
| "Trying to read past end of circular buffer.\n"); |
| |
| const off_t real_start((offset + _start) % buf.size()); |
| if (real_start + len <= buf.size()) { |
| std::copy(buf.begin() + real_start, |
| buf.begin() + real_start + len, |
| out); |
| } else { |
| const size_t head_size(buf.size() - real_start); |
| const size_t tail_size(len - head_size); |
| std::copy(buf.begin() + real_start, buf.end(), |
| out); |
| std::copy(buf.begin(), buf.begin() + tail_size, |
| out + head_size); |
| } |
| } |
| |
| /** |
| * Copy buffer contents and advance the read pointer |
| * |
| * @param out Output iterator/pointer |
| * @param len Number of elements to read |
| */ |
| template <class OutputIterator> |
| void read(OutputIterator out, size_t len) { |
| peek(out, len); |
| |
| _start += len; |
| normalize(); |
| } |
| |
| /** |
| * Add elements to the end of the ring buffers and advance. |
| * |
| * @param in Input iterator/pointer |
| * @param len Number of elements to read |
| */ |
| template <class InputIterator> |
| void write(InputIterator in, size_t len) { |
| // Writes that are larger than the backing store are allowed, |
| // but only the last part of the buffer will be written. |
| if (len > buf.size()) { |
| in += len - buf.size(); |
| len = buf.size(); |
| } |
| |
| const size_t next(_stop % buf.size()); |
| const size_t head_len(std::min(buf.size() - next, len)); |
| |
| std::copy(in, in + head_len, buf.begin() + next); |
| std::copy(in + head_len, in + len, buf.begin()); |
| |
| _stop += len; |
| // We may have written past the old _start pointer. Readjust |
| // the _start pointer to remove the oldest entries in that |
| // case. |
| if (size() > buf.size()) |
| _start = _stop - buf.size(); |
| |
| normalize(); |
| } |
| |
| protected: |
| /** |
| * Normalize the start and stop pointers to ensure that pointer |
| * invariants hold after updates. |
| */ |
| void normalize() { |
| if (_start >= buf.size()) { |
| _stop -= buf.size(); |
| _start -= buf.size(); |
| } |
| |
| assert(_start < buf.size()); |
| assert(_stop < 2 * buf.size()); |
| assert(_start <= _stop); |
| } |
| |
| protected: |
| std::vector<value_type> buf; |
| size_t _start; |
| size_t _stop; |
| |
| }; |
| |
| |
| /** |
| * Simple FIFO implementation backed by a circular buffer. |
| * |
| * This class provides the same basic functionallity as the circular |
| * buffer with the folling differences: |
| * <ul> |
| * <li>Writes are checked to ensure that overflows can't happen. |
| * <li>Unserialization ensures that the data in the checkpoint fits |
| * in the buffer. |
| * </ul> |
| */ |
| template<typename T> |
| class Fifo |
| { |
| public: |
| typedef T value_type; |
| |
| public: |
| Fifo(size_t size) |
| : buf(size) {} |
| |
| bool empty() const { return buf.empty(); } |
| size_t size() const { return buf.size(); } |
| size_t capacity() const { return buf.capacity(); } |
| |
| void flush() { buf.flush(); } |
| |
| template <class OutputIterator> |
| void peek(OutputIterator out, size_t len) const { buf.peek(out, len); } |
| template <class OutputIterator> |
| void read(OutputIterator out, size_t len) { buf.read(out, len); } |
| |
| template <class InputIterator> |
| void write(InputIterator in, size_t len) { |
| panic_if(size() + len > capacity(), |
| "Trying to overfill FIFO buffer.\n"); |
| buf.write(in, len); |
| } |
| |
| private: |
| CircleBuf<value_type> buf; |
| }; |
| |
| |
| template <typename T> |
| static void |
| arrayParamOut(CheckpointOut &cp, const std::string &name, |
| const CircleBuf<T> ¶m) |
| { |
| std::vector<T> temp(param.size()); |
| param.peek(temp.begin(), temp.size()); |
| arrayParamOut(cp, name, temp); |
| } |
| |
| template <typename T> |
| static void |
| arrayParamIn(CheckpointIn &cp, const std::string &name, |
| CircleBuf<T> ¶m) |
| { |
| std::vector<T> temp; |
| arrayParamIn(cp, name, temp); |
| |
| param.flush(); |
| param.write(temp.cbegin(), temp.size()); |
| } |
| |
| template <typename T> |
| static void |
| arrayParamOut(CheckpointOut &cp, const std::string &name, |
| const Fifo<T> ¶m) |
| { |
| std::vector<T> temp(param.size()); |
| param.peek(temp.begin(), temp.size()); |
| arrayParamOut(cp, name, temp); |
| } |
| |
| template <typename T> |
| static void |
| arrayParamIn(CheckpointIn &cp, const std::string &name, |
| Fifo<T> ¶m) |
| { |
| std::vector<T> temp; |
| arrayParamIn(cp, name, temp); |
| |
| fatal_if(param.capacity() < temp.size(), |
| "Trying to unserialize data into too small FIFO\n"); |
| |
| param.flush(); |
| param.write(temp.cbegin(), temp.size()); |
| } |
| |
| #endif // __BASE_CIRCLEBUF_HH__ |