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-rw-r--r--Makefile.am1
-rw-r--r--src/util/DynamicFifoBuffer.hxx147
-rw-r--r--src/util/ForeignFifoBuffer.hxx219
3 files changed, 248 insertions, 119 deletions
diff --git a/Makefile.am b/Makefile.am
index cb85dd5ae..212d198cf 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -373,6 +373,7 @@ libutil_a_SOURCES = \
src/util/Manual.hxx \
src/util/RefCount.hxx \
src/util/FifoBuffer.hxx \
+ src/util/ForeignFifoBuffer.hxx \
src/util/DynamicFifoBuffer.hxx \
src/util/ConstBuffer.hxx \
src/util/WritableBuffer.hxx \
diff --git a/src/util/DynamicFifoBuffer.hxx b/src/util/DynamicFifoBuffer.hxx
index f3060dce4..d441b4484 100644
--- a/src/util/DynamicFifoBuffer.hxx
+++ b/src/util/DynamicFifoBuffer.hxx
@@ -30,14 +30,7 @@
#ifndef FIFO_BUFFER_HPP
#define FIFO_BUFFER_HPP
-#include "WritableBuffer.hxx"
-
-#include <utility>
-#include <algorithm>
-
-#include <assert.h>
-#include <stddef.h>
-#include <stdint.h>
+#include "ForeignFifoBuffer.hxx"
/**
* A first-in-first-out buffer: you can append data at the end, and
@@ -45,93 +38,49 @@
* buffer as needed. It is not thread safe.
*/
template<typename T>
-class DynamicFifoBuffer {
+class DynamicFifoBuffer : protected ForeignFifoBuffer<T> {
public:
- typedef size_t size_type;
- typedef WritableBuffer<T> Range;
- typedef typename Range::pointer_type pointer_type;
- typedef typename Range::const_pointer_type const_pointer_type;
+ typedef typename ForeignFifoBuffer<T>::size_type size_type;
+ typedef typename ForeignFifoBuffer<T>::pointer_type pointer_type;
+ typedef typename ForeignFifoBuffer<T>::const_pointer_type const_pointer_type;
-protected:
- size_type head, tail, capacity;
- T *data;
-
-public:
explicit DynamicFifoBuffer(size_type _capacity)
- :head(0), tail(0), capacity(_capacity),
- data(new T[capacity]) {}
+ :ForeignFifoBuffer<T>(new T[_capacity], _capacity) {}
~DynamicFifoBuffer() {
- delete[] data;
+ delete[] GetBuffer();
}
DynamicFifoBuffer(const DynamicFifoBuffer &) = delete;
- size_type GetCapacity() {
- return capacity;
- }
+ using ForeignFifoBuffer<T>::IsEmpty;
+ using ForeignFifoBuffer<T>::IsFull;
+ using ForeignFifoBuffer<T>::Read;
+ using ForeignFifoBuffer<T>::Consume;
+ using ForeignFifoBuffer<T>::Write;
+ using ForeignFifoBuffer<T>::Append;
void Grow(size_type new_capacity) {
- assert(new_capacity > capacity);
+ assert(new_capacity > GetCapacity());
+ T *old_data = GetBuffer();
T *new_data = new T[new_capacity];
- std::move(data + head, data + tail, new_data);
- delete[] data;
- data = new_data;
- capacity = new_capacity;
- tail -= head;
- head = 0;
- }
-
- void Clear() {
- head = tail = 0;
- }
-
- bool IsEmpty() const {
- return head == tail;
- }
-
- bool IsFull() const {
- return head == 0 && tail == capacity;
- }
-
- /**
- * Prepares writing. Returns a buffer range which may be written.
- * When you are finished, call append().
- */
- Range Write() {
- Shift();
- return Range(data + tail, capacity - tail);
- }
-
- /**
- * Expands the tail of the buffer, after data has been written to
- * the buffer returned by write().
- */
- void Append(size_type n) {
- assert(tail <= capacity);
- assert(n <= capacity);
- assert(tail + n <= capacity);
-
- tail += n;
+ ForeignFifoBuffer<T>::MoveBuffer(new_data, new_capacity);
+ delete[] old_data;
}
void WantWrite(size_type n) {
- if (tail + n <= capacity)
- /* enough space after the tail */
+ if (ForeignFifoBuffer<T>::WantWrite(n))
+ /* we already have enough space */
return;
- const size_type in_use = tail - head;
+ const size_type in_use = Read().size;
const size_type required_capacity = in_use + n;
- if (capacity >= required_capacity) {
- Shift();
- } else {
- size_type new_capacity = capacity;
- do {
- new_capacity <<= 1;
- } while (new_capacity < required_capacity);
+ size_type new_capacity = GetCapacity();
+ do {
+ new_capacity <<= 1;
+ } while (new_capacity < required_capacity);
- Grow(new_capacity);
- }
+ Grow(new_capacity);
}
/**
@@ -140,7 +89,7 @@ public:
*/
pointer_type Write(size_type n) {
WantWrite(n);
- return data + tail;
+ return Write().data;
}
/**
@@ -151,49 +100,9 @@ public:
Append(n);
}
- /**
- * Return a buffer range which may be read. The buffer pointer is
- * writable, to allow modifications while parsing.
- */
- Range Read() {
- return Range(data + head, tail - head);
- }
-
- /**
- * Marks a chunk as consumed.
- */
- void Consume(size_type n) {
- assert(tail <= capacity);
- assert(head <= tail);
- assert(n <= tail);
- assert(head + n <= tail);
-
- head += n;
- }
-
- size_type Read(pointer_type p, size_type n) {
- auto range = Read();
- if (n > range.size)
- n = range.size;
- std::copy_n(range.data, n, p);
- Consume(n);
- return n;
- }
-
protected:
- void Shift() {
- if (head == 0)
- return;
-
- assert(head <= capacity);
- assert(tail <= capacity);
- assert(tail >= head);
-
- std::move(data + head, data + tail, data);
-
- tail -= head;
- head = 0;
- }
+ using ForeignFifoBuffer<T>::GetBuffer;
+ using ForeignFifoBuffer<T>::GetCapacity;
};
#endif
diff --git a/src/util/ForeignFifoBuffer.hxx b/src/util/ForeignFifoBuffer.hxx
new file mode 100644
index 000000000..c119fb6d5
--- /dev/null
+++ b/src/util/ForeignFifoBuffer.hxx
@@ -0,0 +1,219 @@
+/*
+ * Copyright (C) 2003-2014 Max Kellermann <max@duempel.org>
+ *
+ * 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.
+ *
+ * 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
+ * FOUNDATION 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.
+ */
+
+#ifndef FOREIGN_FIFO_BUFFER_HXX
+#define FOREIGN_FIFO_BUFFER_HXX
+
+#include "WritableBuffer.hxx"
+
+#include <utility>
+#include <algorithm>
+
+#include <cstddef>
+
+#include <assert.h>
+
+/**
+ * A first-in-first-out buffer: you can append data at the end, and
+ * read data from the beginning. This class automatically shifts the
+ * buffer as needed. It is not thread safe.
+ *
+ * This class does not manage buffer memory. It will not allocate or
+ * free any memory, it only manages the contents of an existing buffer
+ * given to the constructor.
+ */
+template<typename T>
+class ForeignFifoBuffer {
+public:
+ typedef size_t size_type;
+ typedef WritableBuffer<T> Range;
+ typedef typename Range::pointer_type pointer_type;
+ typedef typename Range::const_pointer_type const_pointer_type;
+
+protected:
+ size_type head, tail, capacity;
+ T *data;
+
+public:
+ explicit constexpr ForeignFifoBuffer(std::nullptr_t n)
+ :head(0), tail(0), capacity(0), data(n) {}
+
+ constexpr ForeignFifoBuffer(T *_data, size_type _capacity)
+ :head(0), tail(0), capacity(_capacity), data(_data) {}
+
+ ForeignFifoBuffer(ForeignFifoBuffer &&src)
+ :head(src.head), tail(src.tail),
+ capacity(src.capacity), data(src.data) {
+ src.SetNull();
+ }
+
+ ForeignFifoBuffer &operator=(ForeignFifoBuffer &&src) {
+ head = src.head;
+ tail = src.tail;
+ capacity = src.capacity;
+ data = src.data;
+ src.SetNull();
+ return *this;
+ }
+
+ constexpr bool IsNull() const {
+ return data == nullptr;
+ }
+
+ constexpr bool IsDefined() const {
+ return !IsNull();
+ }
+
+ T *GetBuffer() {
+ return data;
+ }
+
+ constexpr size_type GetCapacity() const {
+ return capacity;
+ }
+
+ void SetNull() {
+ head = tail = 0;
+ capacity = 0;
+ data = nullptr;
+ }
+
+ void SetBuffer(T *_data, size_type _capacity) {
+ assert(_data != nullptr);
+ assert(_capacity > 0);
+
+ head = tail = 0;
+ capacity = _capacity;
+ data = _data;
+ }
+
+ void MoveBuffer(T *new_data, size_type new_capacity) {
+ assert(new_capacity >= tail - head);
+
+ std::move(data + head, data + tail, new_data);
+ data = new_data;
+ capacity = new_capacity;
+ tail -= head;
+ head = 0;
+ }
+
+ void Clear() {
+ head = tail = 0;
+ }
+
+ constexpr bool IsEmpty() const {
+ return head == tail;
+ }
+
+ constexpr bool IsFull() const {
+ return head == 0 && tail == capacity;
+ }
+
+ /**
+ * Prepares writing. Returns a buffer range which may be written.
+ * When you are finished, call append().
+ */
+ Range Write() {
+ Shift();
+ return Range(data + tail, capacity - tail);
+ }
+
+ bool WantWrite(size_type n) {
+ if (tail + n <= capacity)
+ /* enough space after the tail */
+ return true;
+
+ const size_type in_use = tail - head;
+ const size_type required_capacity = in_use + n;
+ if (required_capacity > capacity)
+ return false;
+
+ Shift();
+ assert(tail + n <= capacity);
+ return true;
+ }
+
+ /**
+ * Expands the tail of the buffer, after data has been written to
+ * the buffer returned by write().
+ */
+ void Append(size_type n) {
+ assert(tail <= capacity);
+ assert(n <= capacity);
+ assert(tail + n <= capacity);
+
+ tail += n;
+ }
+
+ /**
+ * Return a buffer range which may be read. The buffer pointer is
+ * writable, to allow modifications while parsing.
+ */
+ constexpr Range Read() const {
+ return Range(data + head, tail - head);
+ }
+
+ /**
+ * Marks a chunk as consumed.
+ */
+ void Consume(size_type n) {
+ assert(tail <= capacity);
+ assert(head <= tail);
+ assert(n <= tail);
+ assert(head + n <= tail);
+
+ head += n;
+ }
+
+ size_type Read(pointer_type p, size_type n) {
+ auto range = Read();
+ if (n > range.size)
+ n = range.size;
+ std::copy_n(range.data, n, p);
+ Consume(n);
+ return n;
+ }
+
+protected:
+ void Shift() {
+ if (head == 0)
+ return;
+
+ assert(head <= capacity);
+ assert(tail <= capacity);
+ assert(tail >= head);
+
+ std::move(data + head, data + tail, data);
+
+ tail -= head;
+ head = 0;
+ }
+};
+
+#endif