base: Rewrite the CircleBuf to fix bugs and add serialization
The CircleBuf class has at least one bug causing it to overwrite the wrong elements when wrapping. The current code has a lot of unused functionality and duplicated code. This changeset replaces the old implementation with a new version that supports serialization and arbitrary types in the buffer (not just char).
This commit is contained in:
Andreas Sandberg
@@ -37,7 +37,6 @@ Source('atomicio.cc')
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Source('bigint.cc')
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Source('bitmap.cc')
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Source('callback.cc')
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Source('circlebuf.cc')
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Source('cprintf.cc')
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Source('debug.cc')
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if env['USE_FENV']:
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@@ -1,215 +0,0 @@
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/*
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* Copyright (c) 2002-2005 The Regents of The University of Michigan
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met: redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer;
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* redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution;
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* neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* Authors: Nathan Binkert
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*/
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#include <algorithm>
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#include <cstdio>
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#include <cstring>
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#include <string>
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#include "base/atomicio.hh"
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#include "base/circlebuf.hh"
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#include "base/cprintf.hh"
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#include "base/intmath.hh"
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using namespace std;
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CircleBuf::CircleBuf(int l)
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: _rollover(false), _buflen(l), _size(0), _start(0), _stop(0)
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{
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_buf = new char[_buflen];
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}
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CircleBuf::~CircleBuf()
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{
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if (_buf)
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delete [] _buf;
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}
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void
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CircleBuf::dump()
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{
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cprintf("start = %10d, stop = %10d, buflen = %10d\n",
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_start, _stop, _buflen);
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fflush(stdout);
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atomic_write(STDOUT_FILENO, _buf, _buflen);
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atomic_write(STDOUT_FILENO, "<\n", 2);
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}
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void
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CircleBuf::flush()
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{
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_start = 0;
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_stop = 0;
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_size = 0;
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_rollover = false;
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}
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void
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CircleBuf::read(char *b, int len)
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{
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_size -= len;
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if (_size < 0)
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_size = 0;
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if (_stop > _start) {
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len = min(len, _stop - _start);
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memcpy(b, _buf + _start, len);
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_start += len;
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}
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else {
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int endlen = _buflen - _start;
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if (endlen > len) {
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memcpy(b, _buf + _start, len);
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_start += len;
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}
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else {
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memcpy(b, _buf + _start, endlen);
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_start = min(len - endlen, _stop);
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memcpy(b + endlen, _buf, _start);
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}
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}
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}
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void
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CircleBuf::read(int fd, int len)
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{
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_size -= len;
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if (_size < 0)
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_size = 0;
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if (_stop > _start) {
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len = min(len, _stop - _start);
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atomic_write(fd, _buf + _start, len);
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_start += len;
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}
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else {
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int endlen = _buflen - _start;
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if (endlen > len) {
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atomic_write(fd, _buf + _start, len);
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_start += len;
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}
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else {
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atomic_write(fd, _buf + _start, endlen);
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_start = min(len - endlen, _stop);
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atomic_write(fd, _buf, _start);
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}
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}
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}
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void
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CircleBuf::read(int fd)
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{
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_size = 0;
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if (_stop > _start) {
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atomic_write(fd, _buf + _start, _stop - _start);
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}
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else {
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atomic_write(fd, _buf + _start, _buflen - _start);
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atomic_write(fd, _buf, _stop);
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}
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_start = _stop;
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}
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void
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CircleBuf::read(ostream &out)
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{
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_size = 0;
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if (_stop > _start) {
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out.write(_buf + _start, _stop - _start);
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}
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else {
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out.write(_buf + _start, _buflen - _start);
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out.write(_buf, _stop);
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}
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_start = _stop;
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}
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void
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CircleBuf::readall(int fd)
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{
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if (_rollover)
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atomic_write(fd, _buf + _stop, _buflen - _stop);
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atomic_write(fd, _buf, _stop);
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_start = _stop;
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}
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void
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CircleBuf::write(char b)
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{
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write(&b, 1);
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}
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void
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CircleBuf::write(const char *b)
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{
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write(b, strlen(b));
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}
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void
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CircleBuf::write(const char *b, int len)
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{
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if (len <= 0)
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return;
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_size += len;
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if (_size > _buflen)
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_size = _buflen;
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int old_start = _start;
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int old_stop = _stop;
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if (len >= _buflen) {
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_start = 0;
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_stop = _buflen;
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_rollover = true;
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memcpy(_buf, b + (len - _buflen), _buflen);
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return;
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}
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if (_stop + len <= _buflen) {
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memcpy(_buf + _stop, b, len);
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_stop += len;
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} else {
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int end_len = _buflen - old_stop;
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_stop = len - end_len;
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memcpy(_buf + old_stop, b, end_len);
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memcpy(_buf, b + end_len, _stop);
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_rollover = true;
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}
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if ((old_start > old_stop && old_start < _stop) ||
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(old_start < old_stop && _stop < old_stop))
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_start = _stop + 1;
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}
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@@ -1,6 +1,15 @@
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/*
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* Copyright (c) 2002-2005 The Regents of The University of Michigan
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* All rights reserved.
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* Copyright (c) 2015 ARM Limited
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* All rights reserved
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*
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* The license below extends only to copyright in the software and shall
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* not be construed as granting a license to any other intellectual
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* property including but not limited to intellectual property relating
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* to a hardware implementation of the functionality of the software
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* licensed hereunder. You may use the software subject to the license
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* terms below provided that you ensure that this notice is replicated
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* unmodified and in its entirety in all distributions of the software,
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* modified or unmodified, in source code or in binary form.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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@@ -25,40 +34,251 @@
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* Authors: Nathan Binkert
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* Authors: Andreas Sandberg
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*/
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#ifndef __CIRCLEBUF_HH__
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#define __CIRCLEBUF_HH__
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#ifndef __BASE_CIRCLEBUF_HH__
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#define __BASE_CIRCLEBUF_HH__
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#include <iosfwd>
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#include <algorithm>
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#include <cassert>
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#include <vector>
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#include "base/misc.hh"
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#include "sim/serialize.hh"
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/**
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* Circular buffer backed by a vector
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*
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* The data in the cricular buffer is stored in a standard
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* vector. _start designates the first element in the buffer and _stop
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* points to the last element + 1 (i.e., the position of the next
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* insertion). The _stop index may be outside the range of the backing
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* store, which means that the actual index must be calculated as
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* _stop % capacity.
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*
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* Invariants:
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* <ul>
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* <li>_start <= _stop
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* <li>_start < capacity
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* <li>_stop < 2 * capacity
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* </ul>
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*/
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template<typename T>
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class CircleBuf
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{
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protected:
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char *_buf;
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bool _rollover;
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int _buflen;
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int _size;
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int _start;
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int _stop;
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public:
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typedef T value_type;
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public:
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explicit CircleBuf(int l);
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~CircleBuf();
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explicit CircleBuf(size_t size)
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: buf(size), _start(0), _stop(0) {}
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/** Is the buffer empty? */
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bool empty() const { return _stop == _start; }
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/**
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* Return the maximum number of elements that can be stored in
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* the buffer at any one time.
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*/
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size_t capacity() const { return buf.size(); }
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/** Return the number of elements stored in the buffer. */
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size_t size() const { return _stop - _start; }
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/**
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* Remove all the elements in the buffer.
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*
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* Note: This does not actually remove elements from the backing
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* store.
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*/
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void flush() {
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_start = 0;
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_stop = 0;
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}
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/**
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* Copy buffer contents without advancing the read pointer
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*
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* @param out Output iterator/pointer
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* @param len Number of elements to copy
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*/
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template <class OutputIterator>
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void peek(OutputIterator out, size_t len) const {
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panic_if(len > size(),
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"Trying to read past end of circular buffer.\n");
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if (_start + len <= buf.size()) {
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std::copy(buf.begin() + _start,
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buf.begin() + _start + len,
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out);
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} else {
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const size_t head_size(buf.size() - _start);
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const size_t tail_size(len - head_size);
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std::copy(buf.begin() + _start, buf.end(),
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out);
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std::copy(buf.begin(), buf.begin() + tail_size,
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out + head_size);
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}
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}
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/**
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* Copy buffer contents and advance the read pointer
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*
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* @param out Output iterator/pointer
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* @param len Number of elements to read
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*/
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template <class OutputIterator>
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void read(OutputIterator out, size_t len) {
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peek(out, len);
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_start += len;
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normalize();
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}
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/**
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* Add elements to the end of the ring buffers and advance.
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*
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* @param in Input iterator/pointer
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* @param len Number of elements to read
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*/
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template <class InputIterator>
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void write(InputIterator in, size_t len) {
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// Writes that are larger than the backing store are allowed,
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// but only the last part of the buffer will be written.
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if (len > buf.size()) {
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in += len - buf.size();
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len = buf.size();
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}
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const size_t next(_stop % buf.size());
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const size_t head_len(std::min(buf.size() - next, len));
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std::copy(in, in + head_len, buf.begin() + next);
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std::copy(in + head_len, in + len, buf.begin());
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_stop += len;
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// We may have written past the old _start pointer. Readjust
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// the _start pointer to remove the oldest entries in that
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// case.
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if (size() > buf.size())
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_start = _stop - buf.size();
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normalize();
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}
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protected:
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/**
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* Normalize the start and stop pointers to ensure that pointer
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* invariants hold after updates.
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*/
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void normalize() {
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if (_start >= buf.size()) {
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_stop -= buf.size();
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_start -= buf.size();
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}
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assert(_start < buf.size());
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assert(_stop < 2 * buf.size());
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assert(_start <= _stop);
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}
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protected:
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std::vector<value_type> buf;
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size_t _start;
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size_t _stop;
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bool empty() const { return _size == 0; }
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int size() const { return _size; }
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void dump();
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void flush();
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void read(char *b, int len);
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void read(int fd, int len);
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void read(int fd);
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void read(std::ostream &out);
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void readall(int fd);
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void write(char b);
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void write(const char *b);
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void write(const char *b, int len);
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};
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#endif // __CIRCLEBUF_HH__
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/**
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* Simple FIFO implementation backed by a circular buffer.
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*
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* This class provides the same basic functionallity as the circular
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* buffer with the folling differences:
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* <ul>
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* <li>Writes are checked to ensure that overflows can't happen.
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* <li>Unserialization ensures that the data in the checkpoint fits
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* in the buffer.
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* </ul>
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*/
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template<typename T>
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class Fifo
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{
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public:
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typedef T value_type;
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public:
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Fifo(size_t size)
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: buf(size) {}
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bool empty() const { return buf.empty(); }
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size_t size() const { return buf.size(); }
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size_t capacity() const { return buf.capacity(); }
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void flush() { buf.flush(); }
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template <class OutputIterator>
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void peek(OutputIterator out, size_t len) const { buf.peek(out, len); }
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template <class OutputIterator>
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void read(OutputIterator out, size_t len) { buf.read(out, len); }
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template <class InputIterator>
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void write(InputIterator in, size_t len) {
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panic_if(size() + len > capacity(),
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"Trying to overfill FIFO buffer.\n");
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buf.write(in, len);
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}
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private:
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CircleBuf<value_type> buf;
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};
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template <typename T>
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static void
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arrayParamOut(CheckpointOut &cp, const std::string &name,
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const CircleBuf<T> ¶m)
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{
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std::vector<T> temp(param.size());
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param.peek(temp.begin(), temp.size());
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arrayParamOut(cp, name, temp);
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}
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template <typename T>
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static void
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arrayParamIn(CheckpointIn &cp, const std::string &name,
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CircleBuf<T> ¶m)
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{
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std::vector<T> temp;
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arrayParamIn(cp, name, temp);
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param.flush();
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param.write(temp.cbegin(), temp.size());
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}
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template <typename T>
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static void
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arrayParamOut(CheckpointOut &cp, const std::string &name,
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const Fifo<T> ¶m)
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{
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std::vector<T> temp(param.size());
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param.peek(temp.begin(), temp.size());
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arrayParamOut(cp, name, temp);
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}
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template <typename T>
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static void
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arrayParamIn(CheckpointIn &cp, const std::string &name,
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Fifo<T> ¶m)
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{
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std::vector<T> temp;
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arrayParamIn(cp, name, temp);
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fatal_if(param.capacity() < temp.size(),
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"Trying to unserialize data into too small FIFO\n");
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param.flush();
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param.write(temp.cbegin(), temp.size());
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}
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#endif // __BASE_CIRCLEBUF_HH__
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Block a user