Adds implementation of byte buffer. (#622)

* Initializes the raw buffer pool together with the main buffer pool.

* Adds ByteBuffer header, matching the design document.

src/utils/Buffer.cxx

@@ -32,11 +32,17 @@
  */
 
 #include "utils/Buffer.hxx"
+#include "utils/ByteBuffer.hxx"
 
 DynamicPool *mainBufferPool = nullptr;
+Pool *rawBufferPool = nullptr;
 
 Pool* init_main_buffer_pool()
 {
+    if (!rawBufferPool)
+    {
+        rawBufferPool = new DynamicPool(Bucket::init(sizeof(RawBuffer), 0));
+    }
     if (!mainBufferPool)
     {
         mainBufferPool =

src/utils/ByteBuffer.hxx

@@ -0,0 +1,96 @@
+/** \copyright
+ * Copyright (c) 2022, Balazs Racz
+ * All rights reserved.
+ *
+ * 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 COPYRIGHT HOLDER 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.
+ *
+ * \file ByteBuffer.hxx
+ *
+ * Specialization of the Buffer / Pool infrastructure for untyped data
+ * stream. See { \link doc/byte_buffer.md }
+ *
+ * @author Balazs Racz
+ * @date 17 Apr 2022
+ */
+
+#ifndef _UTILS_BYTEBUFFER_HXX_
+#define _UTILS_BYTEBUFFER_HXX_
+
+#include "utils/Buffer.hxx"
+
+/// This is how many bytes we have in each raw buffer allocation.
+static constexpr unsigned RAWBUFFER_SIZE = 1024;
+
+/// Use this BufferPool to allocate raw buffers.
+extern Pool* rawBufferPool;
+
+/// Container for holding an arbitrary untyped data stream.
+struct RawData
+{
+    uint8_t payload[RAWBUFFER_SIZE];
+};
+
+/// Buffers of this type will be allocated from the rawBufferPool to hold the
+/// payloads of untyped data streams. These buffers are never enqueued into Q
+/// or QList objects.
+using RawBuffer = Buffer<RawData>;
+
+/// Holds a reference to a raw buffer, with the start and size information.
+struct ByteChunk
+{
+    /// Owns a ref for a RawData buffer. If this is nullptr, then the data
+    /// references by this chunk is externally owned.
+    BufferPtr<RawData> ownedData_;
+
+    /// Points to the first byte of the useful data.
+    uint8_t* data_ {nullptr};
+
+    /// How many bytes from data_ does this chunk represent.
+    size_t size_ {0};
+
+    /// @return number of bytes pointed to by this chunk.
+    size_t size() const
+    {
+        return size_;
+    }
+
+    /// Moves forward the data beginning pointer by a given number of
+    /// bytes. Represents that some number of bytes were consumed by the sink.
+    /// @param num_bytes how much data was consumed. Must be <= size().
+    void advance(size_t num_bytes)
+    {
+        HASSERT(num_bytes <= size_);
+        data_ += num_bytes;
+        size_ -= num_bytes;
+    }
+};
+
+/// Buffer type of references. These are enqueued for byte sinks.
+using ByteBuffer = Buffer<ByteChunk>;
+
+template<class T> class FlowInterface;
+
+/// Interface for sending a stream of data from a source to a sink.
+using ByteSink = FlowInterface<ByteBuffer>;
+
+#endif // _UTILS_BYTEBUFFER_HXX_