[freenos] r245 committed - Implemented a Buffer class, for managing an memory buffer....
- From: codesite-noreply@xxxxxxxxxx
- To: freenos@xxxxxxxxxxxxx
- Date: Sun, 02 Aug 2009 10:59:16 +0000
Revision: 245
Author: nieklinnenbank
Date: Sun Aug 2 03:39:06 2009
Log: Implemented a Buffer class, for managing an memory buffer.
This class makes it very easy to implement I/O memory buffers.
It acts as an FIFO: you can append new bytes at the end and remove
bytes at the front. All it does it copying bytes on an internal memory
buffer: it's not the same as an Queue!
http://code.google.com/p/freenos/source/detail?r=245
Added:
/trunk/include/Buffer.h
=======================================
--- /dev/null
+++ /trunk/include/Buffer.h Sun Aug 2 03:39:06 2009
@@ -0,0 +1,144 @@
+/*
+ * Copyright (C) 2009 Niek Linnenbank
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __BUFFER_H
+#define __BUFFER_H
+
+#include <Types.h>
+#include <Macros.h>
+#include <Assert.h>
+#include <string.h>
+
+/**
+ * @brief Represents an abstract buffering datatype.
+ *
+ * This class manages an internal buffer from which bytes
+ * may be taken (moved out) or added (moved in).
+ *
+ */
+class Buffer
+{
+ public:
+
+ /**
+ * @brief Constructor function.
+ *
+ * Responsible for initializing the class members and
+ * allocating a memory buffer.
+ *
+ * @param sz Size of the internal buffer.
+ *
+ * @see buffer
+ */
+ Buffer(Size sz = 8192)
+ {
+ buffer = new u8[sz];
+ size = sz;
+ filled = ZERO;
+ }
+
+ /**
+ * @brief Destructor function.
+ *
+ * Releases the internal memory buffer.
+ *
+ * @see buffer
+ */
+ ~Buffer()
+ {
+ delete buffer;
+ }
+
+ /**
+ * @brief Move bytes into the buffer.
+ *
+ * This function allows moving bytes into the internal
+ * buffer. It will verify whether or not enough remaining
+ * space is available.
+ *
+ * @param buffer Pointer to bytes to insert.
+ * @param num On input, the number of bytes to insert. On
+ * output the number of bytes actually moved in.
+ *
+ * @see buffer
+ */
+ void bytesIn(void *buffer, Size *num)
+ {
+ /* Make prior assumptions. */
+ assertRead(buffer);
+ assertRead(num);
+ assert(filled <= size);
+
+ /*
+ * Calculate the number of bytes to move in, at max.
+ */
+ Size bytes = (size - filled) < *num ?
+ (size - filled) : *num;
+
+ /* Do we have space remaining? */
+ if (bytes)
+ {
+ memcpy(this->buffer + filled, buffer, bytes);
+ this->filled += bytes;
+ }
+ }
+
+ /**
+ * @brief Move bytes out of the buffer.
+ *
+ * This function allows removing bytes from the internal
+ * buffer. It will verify whether or not there are any
+ * bytes available.
+ *
+ * @param num On input, the number of bytes to remove. On
+ * output the number of bytes actually moved out.
+ *
+ * @see buffer
+ */
+ void * bytesOut(Size *num)
+ {
+ /* Make prior assumptions. */
+ assertRead(num);
+ assertWrite(buffer);
+
+ /*
+ * Calculate the number of bytes to move out.
+ */
+ Size bytes = filled < *num ?
+ filled : *num;
+
+ /* Update state. */
+ filled -= bytes;
+ *num = bytes;
+
+ /* Return a pointer to the internal buffer. */
+ return (void *)(buffer + filled);
+ }
+
+ private:
+
+ /** Internal memory buffer managed by this class. */
+ u8 *buffer;
+
+ /** Size of the buffer in bytes. */
+ Size size;
+
+ /** Number of bytes which are occupied. */
+ Size filled;
+};
+
+#endif /* __BUFFER_H */
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