STL-ified the interpolation table so it is not size limited.

diff --git a/simgear/math/interpolater.cxx b/simgear/math/interpolater.cxx
index f0b0a453d5bf43acac9cd79bf2279a9fc7854ff1..d3d743509d7611db4a9d8bbfb44042f9f31a0210 100644 (file)
--- a/simgear/math/interpolater.cxx
+++ b/simgear/math/interpolater.cxx
@@ -38,10 +38,18 @@
 
 SG_USING_STD(string);
 
+// Constructor -- starts with an empty table.
+SGInterpTable::SGInterpTable()
+    : size(0)
+{
+}
+
 
 // Constructor -- loads the interpolation table from the specified
 // file
-SGInterpTable::SGInterpTable( const string& file ) {
+SGInterpTable::SGInterpTable( const string& file ) 
+  : size(0)
+{
     SG_LOG( SG_MATH, SG_INFO, "Initializing Interpolator for " << file );
 
     sg_gzifstream in( file );
@@ -50,56 +58,62 @@ SGInterpTable::SGInterpTable( const string& file ) {
        exit(-1);
     }
 
-    size = 0;
     in >> skipcomment;
     while ( in ) {
-       if ( size < MAX_TABLE_SIZE ) {
-           in >> table[size][0] >> table[size][1];
-           in >> skipws;
-           size++;
-       } else {
-            SG_LOG( SG_MATH, SG_ALERT,
-                   "fgInterpolateInit(): Exceed max table size = "
-                   << MAX_TABLE_SIZE );
-           exit(-1);
-       }
+      double ind, dep;
+      in >> ind >> dep;
+      in >> skipws;
+      table.push_back(Entry(ind, dep));
+      size++;
     }
 }
 
 
+// Add an entry to the table.
+void SGInterpTable::addEntry (double ind, double dep)
+{
+  table.push_back(Entry(ind,dep));
+  size++;
+}
+
+
 // Given an x value, linearly interpolate the y value from the table
-double SGInterpTable::interpolate(double x) {
+double SGInterpTable::interpolate(double x) const
+{
     int i;
     double y;
 
+    if (size == 0.0)
+      return 0.0;
+
     i = 0;
 
-    while ( (x > table[i][0]) && (i < size) ) {
-       // cout << "  i = " << i << " table[i][0] = " << table[i][0] << endl;
+    while ( (i < size) && (x > table[i].ind) ) {
+       // cout << "  i = " << i << " table[i].ind = " << table[i].ind << endl;
        // cout << "  size = " << size << endl;
        i++;
     }
 
     // printf ("i = %d ", i);
 
-    if ( (i == 0) && (x < table[0][0]) ) {
+    if ( (i == 0) && (x < table[0].ind) ) {
        SG_LOG( SG_MATH, SG_DEBUG, 
                "interpolate(): lookup error, x to small = " << x );
-       return table[0][1];
+       return table[0].dep;
     }
 
-    // cout << " table[size-1][0] = " << table[size-1][0] << endl;
-    if ( x > table[size-1][0] ) {
+    // cout << " table[size-1].ind = " << table[size-1].ind << endl;
+    if ( x > table[size-1].ind ) {
        SG_LOG( SG_MATH, SG_DEBUG, 
                "interpolate(): lookup error, x to big = " << x );
-       return table[size-1][1];
+       return table[size-1].dep;
     }
 
     // y = y1 + (y0 - y1)(x - x1) / (x0 - x1)
-    y = table[i][1] + 
-       ( (table[i-1][1] - table[i][1]) * 
-         (x - table[i][0]) ) /
-       (table[i-1][0] - table[i][0]);
+    y = table[i].dep + 
+       ( (table[i-1].dep - table[i].dep) * 
+         (x - table[i].ind) ) /
+       (table[i-1].ind - table[i].ind);
 
     return(y);
 }

diff --git a/simgear/math/interpolater.hxx b/simgear/math/interpolater.hxx
index 501e4ac8d452f54d144c0fd5c7a6d29df5e20a3d..12ce6f3cece68254a4b42258f2a4c21226503a5b 100644 (file)
--- a/simgear/math/interpolater.hxx
+++ b/simgear/math/interpolater.hxx
@@ -36,10 +36,12 @@
 
 #include <simgear/compiler.h>
 
+#include <vector>
+SG_USING_STD(vector);
+
 #include STL_STRING
 SG_USING_STD(string);
 
-#define MAX_TABLE_SIZE 32
 
 /**
  * A class that provids a simple linear 2d interpolation lookup table.
@@ -48,23 +50,49 @@ SG_USING_STD(string);
  * variable can be anything.
  */
 class SGInterpTable {
+
+    struct Entry
+    {
+      Entry ()
+       : ind(0.0L), dep(0.0L) {}
+      Entry (double independent, double dependent)
+       : ind(independent), dep(dependent) {}
+      double ind;
+      double dep;
+    };
+
     int size;
-    double table[MAX_TABLE_SIZE][2];
+    vector<Entry> table;
 
 public:
 
+    /**
+     * Constructor. Creates a new, empty table.
+     */
+    SGInterpTable();
+
     /**
      * Constructor. Loads the interpolation table from the specified file.
      * @param file name of interpolation file
      */
     SGInterpTable( const string& file );
 
+
+    /**
+     * Add an entry to the table, extending the table's length.
+     *
+     * @param ind The independent variable.
+     * @param dep The dependent variable.
+     */
+    void addEntry (double ind, double dep);
+    
+
     /**
      * Given an x value, linearly interpolate the y value from the table.
      * @param x independent variable
      * @return interpolated dependent variable
      */
-    double interpolate(double x);
+    double interpolate(double x) const;
 
     /** Destructor */
     ~SGInterpTable();