JSBSim updates. This update changes the file format, so an update of the base

[flightgear.git] / src / FDM / JSBSim / FGTable.cpp

diff --git a/src/FDM/JSBSim/FGTable.cpp b/src/FDM/JSBSim/FGTable.cpp
index 20e0fdd18320cbb51c205e53a40190ffc299624e..248ca8ebd04038f75bee46e2c1d27f880bb2cae5 100644 (file)
--- a/src/FDM/JSBSim/FGTable.cpp
+++ b/src/FDM/JSBSim/FGTable.cpp
@@ -68,7 +68,7 @@ FGTable::FGTable(int NRows, int NCols) : nRows(NRows), nCols(NCols)
   }
 
   Data = Allocate();
-
+  lastRowIndex=lastColumnIndex=2;
   Debug(0);
 }
 
@@ -82,6 +82,7 @@ FGTable::FGTable(int NRows) : nRows(NRows), nCols(1)
 
   Data = Allocate();
   Debug(0);
+  lastRowIndex=lastColumnIndex=2;
 }
 
 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -112,13 +113,33 @@ FGTable::~FGTable()
 double FGTable::GetValue(double key)
 {
   double Factor, Value, Span;
-  int r;
-
-  for (r=1; r<=nRows; r++) if (Data[r][0] >= key) break;
-  r = r < 2 ? 2 : (r > nRows ? nRows : r);
-
+  int r=lastRowIndex;
+  
+  //if the key is off the end of the table, just return the 
+  //end-of-table value, do not extrapolate
+  if( key <= Data[1][0] ) {
+    lastRowIndex=2;
+    //cout << "Key underneath table: " << key << endl;
+    return Data[1][1];
+  } else if ( key >= Data[nRows][0] ) {
+    lastRowIndex=nRows;
+    //cout << "Key over table: " << key << endl;
+    return Data[nRows][1];
+  }    
+
+  // the key is somewhere in the middle, search for the right breakpoint
+  // assume the correct breakpoint has not changed since last frame or
+  // has only changed very little
+  
+  if ( r > 2 && Data[r-1][0] > key ) {
+    while( Data[r-1][0] > key && r > 2) { r--; }
+  } else if ( Data[r][0] < key ) { 
+    while( Data[r][0] <= key && r <= nRows) { r++; }  
+  }  
+  
+  lastRowIndex=r;  
   // make sure denominator below does not go to zero.
-
+  
   Span = Data[r][0] - Data[r-1][0];
   if (Span != 0.0) {
     Factor = (key - Data[r-1][0]) / Span;
@@ -134,17 +155,31 @@ double FGTable::GetValue(double key)
 
 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
+
 double FGTable::GetValue(double rowKey, double colKey)
 {
   double rFactor, cFactor, col1temp, col2temp, Value;
-  int r, c;
-
-  for (r=1;r<=nRows;r++) if (Data[r][0] >= rowKey) break;
-  for (c=1;c<=nCols;c++) if (Data[0][c] >= colKey) break;
-
-  c = c < 2 ? 2 : (c > nCols ? nCols : c);
-  r = r < 2 ? 2 : (r > nRows ? nRows : r);
-
+  int r=lastRowIndex;
+  int c=lastColumnIndex;
+  
+  if ( r > 2 && Data[r-1][0] > rowKey ) {
+    while ( Data[r-1][0] > rowKey && r > 2) { r--; }
+  } else if ( Data[r][0] < rowKey ) { 
+//    cout << Data[r][0] << endl;
+    while ( r <= nRows && Data[r][0] <= rowKey ) { r++; }
+    if ( r > nRows ) r = nRows;  
+  }  
+  
+  if ( c > 2 && Data[0][c-1] > colKey ) {
+    while( Data[0][c-1] > colKey && c > 2) { c--; }
+  } else if ( Data[0][c] < colKey ) { 
+    while( Data[0][c] <= colKey && c <= nCols) { c++; } 
+    if ( c > nCols ) c = nCols;  
+  }  
+
+  lastRowIndex=r;
+  lastColumnIndex=c;
+  
   rFactor = (rowKey - Data[r-1][0]) / (Data[r][0] - Data[r-1][0]);
   cFactor = (colKey - Data[0][c-1]) / (Data[0][c] - Data[0][c-1]);