Diff: MTSCircularBuffer.h

Revision:

1:9f30fbe9e9c1

diff -r c62615f15125 -r 9f30fbe9e9c1 MTSCircularBuffer.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MTSCircularBuffer.h	Wed Jun 24 17:03:08 2015 -0500
@@ -0,0 +1,165 @@
+/************************************************
+ * MultiTech MTDOT Library
+ * Copyright (c) 2015 MultiTech Systems
+ *
+ * See LICENSE file for license information
+ ***********************************************/
+
+#ifndef MTSCIRCULARBUFFER_H
+#define MTSCIRCULARBUFFER_H
+
+#include "Utils.h"
+
+namespace mts
+{
+
+/** This class provides a circular byte buffer meant for temporary storage
+* during IO transactions.  It contains many of the common methods you
+* would expect from a circular buffer like read, write, and various
+* methods for checking the size or status.  It should be noted that
+* this class does not include any special code for thread safety like
+* a lock.  In most cases this is not problematic, but is something
+* to be aware of.
+*/
+class MTSCircularBuffer
+{
+public:
+    /** Creates an MTSCircularBuffer object with the specified static size.
+    *
+    * @prarm bufferSize size of the buffer in bytes.
+    */
+    MTSCircularBuffer(int bufferSize);
+
+    /** Destructs an MTSCircularBuffer object and frees all related resources.
+    */
+    ~MTSCircularBuffer();
+
+    /** This method enables bulk reads from the buffer.  If more data is
+    * requested then available it simply returns all remaining data within the
+    * buffer.
+    *
+    * @param data the buffer where data read will be added to.
+    * @param length the amount of data in bytes to be read into the buffer.
+    * @returns the total number of bytes that were read.
+    */
+    int read(char* data, int length);
+
+    /** This method reads a single byte from the buffer.
+    *
+    * @param data char where the read byte will be stored.
+    * @returns 1 if byte is read or 0 if no bytes available.
+    */
+    int read(char& data);
+
+    /** This method enables bulk writes to the buffer. If more data
+    * is requested to be written then space available the method writes
+    * as much data as possible and returns the actual amount written.
+    *
+    * @param data the byte array to be written.
+    * @param length the length of data to be written from the data paramter.
+    * @returns the number of bytes written to the buffer, which is 0 if
+    * the buffer is full.
+    */
+    int write(const char* data, int length);
+
+    /** This method writes a signle byte as a char to the buffer.
+    *
+    * @param data the byte to be written as a char.
+    * @returns 1 if the byte was written or 0 if the buffer was full.
+    */
+    int write(char data);
+
+    /** This method is used to setup a callback funtion when the buffer reaches
+    * a certain threshold. The threshold condition is checked after every read
+    * and write call is completed. The condition is made up of both a threshold
+    * value and operator. An example that would trigger a callback is if the
+    * threshold was 10, the operator GREATER, and there were 12 bytes added to an
+    * empty buffer.
+    *
+    * @param tptr a pointer to the object to be called when the condition is met.
+    * @param mptr a pointer to the function within the object to be called when
+    * the condition is met.
+    * @param threshold the value in bytes to be used as part of the condition.
+    * @param op the operator to be used in conjunction with the threshold
+    * as part of the condition.
+    */
+    template<typename T>
+    void attach(T *tptr, void( T::*mptr)(void), int threshold, RelationalOperator op) {
+        _threshold = threshold;
+        _op = op;
+        notify.attach(tptr, mptr);
+    }
+
+    /** This method is used to setup a callback funtion when the buffer reaches
+    * a certain threshold. The threshold condition is checked after every read
+    * and write call is completed. The condition is made up of both a threshold
+    * value and operator. An example that would trigger a callback is if the
+    * threshold was 10, the operator GREATER, and there were 12 bytes added to an
+    * empty buffer.
+    *
+    * @param fptr a pointer to the static function to be called when the condition
+    * is met.
+    * @param threshold the value in bytes to be used as part of the condition.
+    * @param op the operator to be used in conjunction with the threshold
+    * as part of the condition.
+    */
+    void attach(void(*fptr)(void), int threshold, RelationalOperator op) {
+        _threshold = threshold;
+        _op = op;
+        notify.attach(fptr);
+    }
+
+    /** This method returns the size of the storage space currently allocated for
+    * the buffer. This value is equivalent to the one passed into the constructor.
+    * This value is equal or greater than the size() of the buffer.
+    *
+    * @returns the allocated size of the buffer in bytes.
+    */
+    int capacity();
+
+    /** This method returns the amount of space left for writing.
+    *
+    * @returns numbers of unused bytes in buffer.
+    */
+    int remaining();
+
+    /** This method returns the number of bytes available for reading.
+    *
+    * @returns number of bytes currently in buffer.
+    */
+    int size();
+
+    /** This method returns whether the buffer is full.
+    *
+    * @returns true if full, otherwise false.
+    */
+    bool isFull();
+
+    /** This method returns whether the buffer is empty.
+    *
+    * @returns true if empty, otherwise false.
+    */
+    bool isEmpty();
+
+    /** This method clears the buffer. This is done through
+    * setting the internal read and write indexes to the same
+    * value and is therefore not an expensive operation.
+    */
+    void clear();
+
+
+private:
+    int bufferSize; // total size of the buffer
+    char* buffer; // internal byte buffer as a character buffer
+    int readIndex; // read index for circular buffer
+    int writeIndex; // write index for circular buffer
+    int bytes; // available data
+    FunctionPointer notify; // function pointer used for the internal callback notification
+    int _threshold; // threshold for the notification
+    RelationalOperator _op; // operator that determines the direction of the threshold
+    void checkThreshold(); // private function that checks thresholds and processes notifications
+};
+
+}
+
+#endif /* MTSCIRCULARBUFFER_H */