Giacomo Gabrielli has uploaded this change for review. (
https://gem5-review.googlesource.com/c/public/gem5/+/13128
Change subject: base: Ported circlebuf to circularQueue
......................................................................
base: Ported circlebuf to circularQueue
Ported the existing circlebuf on top of the circularQueue to condense
shared functionality and minimise code/functionality replication.
Change-Id: Ib4e67c638f0fb66b54cef77007a03439218bda7f
Signed-off-by: Giacomo Gabrielli <[email protected]>
---
M src/base/circlebuf.hh
1 file changed, 35 insertions(+), 83 deletions(-)
diff --git a/src/base/circlebuf.hh b/src/base/circlebuf.hh
index 2c93daa..5bae86d 100644
--- a/src/base/circlebuf.hh
+++ b/src/base/circlebuf.hh
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2015 ARM Limited
+ * Copyright (c) 2015,2017 ARM Limited
* All rights reserved
*
* The license below extends only to copyright in the software and shall
@@ -44,46 +44,47 @@
#include <cassert>
#include <vector>
+#include "base/circularQueue.hh"
#include "base/logging.hh"
#include "sim/serialize.hh"
/**
- * Circular buffer backed by a vector
+ * Circular buffer backed by a vector though a circularQueue.
*
* 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.
+ * vector.
*
- * Invariants:
- * <ul>
- * <li>_start <= _stop
- * <li>_start < capacity
- * <li>_stop < 2 * capacity
- * </ul>
*/
template<typename T>
-class CircleBuf
+class CircleBuf : public circularQueue<T>
{
- public:
- typedef T value_type;
-
+ protected:
+ using circularQueue<T>::_head;
+ using circularQueue<T>::_tail;
+ using circularQueue<T>::_size;
+ using circularQueue<T>::_empty;
public:
explicit CircleBuf(size_t size)
- : buf(size), _start(0), _stop(0) {}
-
- /** Is the buffer empty? */
- bool empty() const { return _stop == _start; }
+ : circularQueue<T>(size) {}
+ using circularQueue<T>::empty;
+ using circularQueue<T>::begin;
+ using circularQueue<T>::end;
+ using circularQueue<T>::pop_front;
+ using circularQueue<T>::advance_tail;
/**
* Return the maximum number of elements that can be stored in
* the buffer at any one time.
*/
- size_t capacity() const { return buf.size(); }
+ size_t capacity() const { return _size; }
/** Return the number of elements stored in the buffer. */
- size_t size() const { return _stop - _start; }
-
+ size_t size() const {
+ if (_head > _tail)
+ return _head - _tail + 1;
+ else if (_empty)
+ return 0;
+ else
+ return _head + _size - _tail + 1;
+ }
/**
* Remove all the elements in the buffer.
*
@@ -91,8 +92,9 @@
* store.
*/
void flush() {
- _start = 0;
- _stop = 0;
+ _head = _size - 1;
+ _tail = 0;
+ _empty = true;
}
/**
@@ -118,19 +120,7 @@
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);
- }
+ std::copy(begin() + offset, begin() + offset + len, out);
}
/**
@@ -142,9 +132,7 @@
template <class OutputIterator>
void read(OutputIterator out, size_t len) {
peek(out, len);
-
- _start += len;
- normalize();
+ pop_front(len);
}
/**
@@ -157,51 +145,15 @@
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();
+ if (len > _size) {
+ in += len - _size;
+ len = _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();
+ advance_tail(len);
+ std::copy(in, in + len, begin());
}
-
- 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.
*
--
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Gerrit-Project: public/gem5
Gerrit-Branch: master
Gerrit-Change-Id: Ib4e67c638f0fb66b54cef77007a03439218bda7f
Gerrit-Change-Number: 13128
Gerrit-PatchSet: 1
Gerrit-Owner: Giacomo Gabrielli <[email protected]>
Gerrit-MessageType: newchange
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