1/*
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2 * Copyright (c) 2015 ARM Limited
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2 * Copyright (c) 2015,2017-2018 ARM Limited |
3 * All rights reserved 4 * 5 * The license below extends only to copyright in the software and shall 6 * not be construed as granting a license to any other intellectual 7 * property including but not limited to intellectual property relating 8 * to a hardware implementation of the functionality of the software 9 * licensed hereunder. You may use the software subject to the license 10 * terms below provided that you ensure that this notice is replicated 11 * unmodified and in its entirety in all distributions of the software, 12 * modified or unmodified, in source code or in binary form. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions are 16 * met: redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer; 18 * redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution; 21 * neither the name of the copyright holders nor the names of its 22 * contributors may be used to endorse or promote products derived from 23 * this software without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 26 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 27 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 28 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 29 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 35 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 36 * 37 * Authors: Andreas Sandberg 38 */ 39 40#ifndef __BASE_CIRCLEBUF_HH__ 41#define __BASE_CIRCLEBUF_HH__ 42 43#include <algorithm> 44#include <cassert> 45#include <vector> 46
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47#include "base/circular_queue.hh" |
48#include "base/logging.hh" 49#include "sim/serialize.hh" 50 51/**
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51 * Circular buffer backed by a vector
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52 * Circular buffer backed by a vector though a CircularQueue. |
53 * 54 * The data in the cricular buffer is stored in a standard
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54 * vector. _start designates the first element in the buffer and _stop
55 * points to the last element + 1 (i.e., the position of the next
56 * insertion). The _stop index may be outside the range of the backing
57 * store, which means that the actual index must be calculated as
58 * _stop % capacity.
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55 * vector. |
56 *
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60 * Invariants:
61 * <ul>
62 * <li>_start <= _stop
63 * <li>_start < capacity
64 * <li>_stop < 2 * capacity
65 * </ul>
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57 */ 58template<typename T>
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68class CircleBuf
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59class CircleBuf : public CircularQueue<T> |
60{ 61 public:
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71 typedef T value_type;
72
73 public:
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62 explicit CircleBuf(size_t size)
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75 : buf(size), _start(0), _stop(0) {}
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63 : CircularQueue<T>(size) {} 64 using CircularQueue<T>::empty; 65 using CircularQueue<T>::size; 66 using CircularQueue<T>::capacity; 67 using CircularQueue<T>::begin; 68 using CircularQueue<T>::end; 69 using CircularQueue<T>::pop_front; 70 using CircularQueue<T>::advance_tail; |
71
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77 /** Is the buffer empty? */
78 bool empty() const { return _stop == _start; }
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72 /**
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80 * Return the maximum number of elements that can be stored in
81 * the buffer at any one time.
82 */
83 size_t capacity() const { return buf.size(); }
84 /** Return the number of elements stored in the buffer. */
85 size_t size() const { return _stop - _start; }
86
87 /**
88 * Remove all the elements in the buffer.
89 *
90 * Note: This does not actually remove elements from the backing
91 * store.
92 */
93 void flush() {
94 _start = 0;
95 _stop = 0;
96 }
97
98 /**
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73 * Copy buffer contents without advancing the read pointer 74 * 75 * @param out Output iterator/pointer 76 * @param len Number of elements to copy 77 */ 78 template <class OutputIterator> 79 void peek(OutputIterator out, size_t len) const { 80 peek(out, 0, len); 81 } 82 83 /** 84 * Copy buffer contents without advancing the read pointer 85 * 86 * @param out Output iterator/pointer 87 * @param offset Offset into the ring buffer 88 * @param len Number of elements to copy 89 */ 90 template <class OutputIterator> 91 void peek(OutputIterator out, off_t offset, size_t len) const { 92 panic_if(offset + len > size(), 93 "Trying to read past end of circular buffer.\n"); 94
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121 const off_t real_start((offset + _start) % buf.size());
122 if (real_start + len <= buf.size()) {
123 std::copy(buf.begin() + real_start,
124 buf.begin() + real_start + len,
125 out);
126 } else {
127 const size_t head_size(buf.size() - real_start);
128 const size_t tail_size(len - head_size);
129 std::copy(buf.begin() + real_start, buf.end(),
130 out);
131 std::copy(buf.begin(), buf.begin() + tail_size,
132 out + head_size);
133 }
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95 std::copy(begin() + offset, begin() + offset + len, out); |
96 } 97 98 /** 99 * Copy buffer contents and advance the read pointer 100 * 101 * @param out Output iterator/pointer 102 * @param len Number of elements to read 103 */ 104 template <class OutputIterator> 105 void read(OutputIterator out, size_t len) { 106 peek(out, len);
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145
146 _start += len;
147 normalize();
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107 pop_front(len); |
108 } 109 110 /** 111 * Add elements to the end of the ring buffers and advance. 112 * 113 * @param in Input iterator/pointer 114 * @param len Number of elements to read 115 */ 116 template <class InputIterator> 117 void write(InputIterator in, size_t len) { 118 // Writes that are larger than the backing store are allowed, 119 // but only the last part of the buffer will be written.
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160 if (len > buf.size()) {
161 in += len - buf.size();
162 len = buf.size();
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120 if (len > capacity()) { 121 in += len - capacity(); 122 len = capacity(); |
123 } 124
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165 const size_t next(_stop % buf.size());
166 const size_t head_len(std::min(buf.size() - next, len));
167
168 std::copy(in, in + head_len, buf.begin() + next);
169 std::copy(in + head_len, in + len, buf.begin());
170
171 _stop += len;
172 // We may have written past the old _start pointer. Readjust
173 // the _start pointer to remove the oldest entries in that
174 // case.
175 if (size() > buf.size())
176 _start = _stop - buf.size();
177
178 normalize();
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125 std::copy(in, in + len, end()); 126 advance_tail(len); |
127 }
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180
181 protected:
182 /**
183 * Normalize the start and stop pointers to ensure that pointer
184 * invariants hold after updates.
185 */
186 void normalize() {
187 if (_start >= buf.size()) {
188 _stop -= buf.size();
189 _start -= buf.size();
190 }
191
192 assert(_start < buf.size());
193 assert(_stop < 2 * buf.size());
194 assert(_start <= _stop);
195 }
196
197 protected:
198 std::vector<value_type> buf;
199 size_t _start;
200 size_t _stop;
201
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128}; 129
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204
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130/** 131 * Simple FIFO implementation backed by a circular buffer. 132 * 133 * This class provides the same basic functionallity as the circular 134 * buffer with the folling differences: 135 * <ul> 136 * <li>Writes are checked to ensure that overflows can't happen. 137 * <li>Unserialization ensures that the data in the checkpoint fits 138 * in the buffer. 139 * </ul> 140 */ 141template<typename T> 142class Fifo 143{ 144 public: 145 typedef T value_type; 146 147 public: 148 Fifo(size_t size) 149 : buf(size) {} 150 151 bool empty() const { return buf.empty(); } 152 size_t size() const { return buf.size(); } 153 size_t capacity() const { return buf.capacity(); } 154 155 void flush() { buf.flush(); } 156 157 template <class OutputIterator> 158 void peek(OutputIterator out, size_t len) const { buf.peek(out, len); } 159 template <class OutputIterator> 160 void read(OutputIterator out, size_t len) { buf.read(out, len); } 161 162 template <class InputIterator> 163 void write(InputIterator in, size_t len) { 164 panic_if(size() + len > capacity(), 165 "Trying to overfill FIFO buffer.\n"); 166 buf.write(in, len); 167 } 168 169 private: 170 CircleBuf<value_type> buf; 171}; 172 173 174template <typename T> 175void 176arrayParamOut(CheckpointOut &cp, const std::string &name, 177 const CircleBuf<T> ¶m) 178{ 179 std::vector<T> temp(param.size()); 180 param.peek(temp.begin(), temp.size()); 181 arrayParamOut(cp, name, temp); 182} 183 184template <typename T> 185void 186arrayParamIn(CheckpointIn &cp, const std::string &name, 187 CircleBuf<T> ¶m) 188{ 189 std::vector<T> temp; 190 arrayParamIn(cp, name, temp); 191 192 param.flush(); 193 param.write(temp.cbegin(), temp.size()); 194} 195 196template <typename T> 197void 198arrayParamOut(CheckpointOut &cp, const std::string &name, 199 const Fifo<T> ¶m) 200{ 201 std::vector<T> temp(param.size()); 202 param.peek(temp.begin(), temp.size()); 203 arrayParamOut(cp, name, temp); 204} 205 206template <typename T> 207void 208arrayParamIn(CheckpointIn &cp, const std::string &name, 209 Fifo<T> ¶m) 210{ 211 std::vector<T> temp; 212 arrayParamIn(cp, name, temp); 213 214 fatal_if(param.capacity() < temp.size(), 215 "Trying to unserialize data into too small FIFO\n"); 216 217 param.flush(); 218 param.write(temp.cbegin(), temp.size()); 219} 220 221#endif // __BASE_CIRCLEBUF_HH__
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