Diff: SlidingWindow.cpp

Revision:

63:ed787f5fcdc4

diff -r 86d24b9480b9 -r ed787f5fcdc4 SlidingWindow.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SlidingWindow.cpp	Sun Mar 23 16:27:55 2014 +0000
@@ -0,0 +1,98 @@
+
+//#include <windows.h>
+#include "SlidingWindow.h"
+#include <mbed.h>
+//#include <stdio.h>
+//#include <stdlib.h>
+
+// Define this to implement tracking code.
+//#define M_TRACK
+
+SlidingWindow::SlidingWindow(int desiredSize, int allowedSize)
+{
+    m_forewardUsed = 0;
+    m_backwardUsed = 0;
+    m_desiredSize = desiredSize;
+    m_allowedSize = allowedSize;
+    m_buf = (unsigned char *)malloc(allowedSize);
+    if (m_buf) {
+        m_status = noerror;
+    } else {
+        m_status = outofmemory;
+    }
+    #ifdef M_TRACK
+    m_used = (unsigned char *)malloc(allowedSize);
+    for (int i=0; i<allowedSize; i++)
+        m_used[i] = 0;
+    #endif
+}
+SlidingWindow::~SlidingWindow()
+{
+    //char buf[100];
+    //sprintf_s(buf, sizeof(buf), "forewardUsed: %d\n", m_forewardUsed);
+    //OutputDebugString(buf);
+    //sprintf_s(buf, sizeof(buf), "backwardUsed: %d\n", m_backwardUsed);
+    //OutputDebugString(buf);
+    free(m_buf);
+    #ifdef M_TRACK
+    free(m_used);
+    #endif
+}
+
+
+
+bool SlidingWindow::set(int x, unsigned char value)
+{
+    if (x >= 0)
+    {
+        if (x >= m_allowedSize)
+        {
+            x %= m_allowedSize;
+        }
+        
+        m_buf[x] = value;
+        #ifdef M_TRACK
+        m_used[x] = 1;
+        #endif
+        if (x > m_forewardUsed)
+            m_forewardUsed = x;
+        return true;
+    }
+    else
+    {
+        m_buf[m_allowedSize + x] = value;
+        #ifdef M_TRACK
+        m_used[m_allowedSize + x] = 1;
+        #endif
+        return true;
+    }
+}
+unsigned char SlidingWindow::get(int foreDistance, int backDistance)
+{
+    int d = foreDistance - backDistance;
+
+    if (d >= 0)
+    {
+        if (d > m_allowedSize)
+            d %= m_allowedSize;     // instead of this, if m_allowedSize < m_desiredSize, and if memory is available, it could reallocate and fix itself
+        #ifdef M_TRACK
+        if (!m_used[d])
+            ERR("buffer location %d was never set\n", d);
+        #endif
+        return m_buf[d];
+    }
+    else
+    {
+        if (d < m_backwardUsed)
+            m_backwardUsed = d;
+        while (d < -m_allowedSize)
+            d %= m_allowedSize;
+        //if (!m_used[m_allowedSize + d])
+        //{
+        //    char buf[100];
+        //    sprintf_s(buf, sizeof(buf), "Accessing unitialized location [%d]\n", foreDistance - backDistance);
+        //    OutputDebugString(buf);
+        //}
+        return m_buf[m_allowedSize + d];
+    }
+}
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