Added 8 precision digit support in preparation for v2.1.0

Author: mapcodefoundation

.gitignore

@@ -1,3 +1,4 @@
 target/
 out/
+_build*.*
 *.versionsBackup

src/main/java/com/mapcode/Decoder.java

@@ -342,7 +342,7 @@ private static Point decodeGrid(final String str, final int minx, final int miny
         final int cornery = rely + (dify * dividery);
         final int cornerx = relx + (difx * dividerx);
 
-        return decodeExtension(cornery, cornerx, dividerx << 2, dividery, 1, extrapostfix);
+        return decodeExtension(cornery, cornerx, dividerx << 2, dividery, extrapostfix, 0); // grid
     }
 
     @Nonnull
@@ -447,7 +447,7 @@ private static Point decodeNameless(final String str, final int firstrec, final
 
         final int cornerx = minx + ((dx * dividerx4) / 4);
         final int cornery = maxy - (dy * dividery);
-        return decodeExtension(cornery, cornerx, dividerx4, dividery, -1, extrapostfix);
+        return decodeExtension(cornery, cornerx, dividerx4, -dividery, extrapostfix, ((dx * dividerx4) % 4) ); // nameless
     }
 
     @Nonnull
@@ -506,7 +506,7 @@ private static Point decodeAutoHeader(final String input, final int m, final Str
                     return Point.undefined(); // corner out of bounds
                 }
 
-                return decodeExtension(cornery, cornerx, dividerx << 2, dividery, -1, extrapostfix);
+                return decodeExtension(cornery, cornerx, dividerx << 2, -dividery, extrapostfix, 0); // autoheader
             }
             storageStart += product;
             i++;
@@ -717,28 +717,65 @@ private static int decodeBase31(final String code) {
     }
 
     @Nonnull
-    private static Point decodeExtension(final int y, final int x, final int dividerx4, final int dividery, final int ydirection, final String extrapostfix) {
-        if (!extrapostfix.isEmpty()) {
-            int c1 = (int) extrapostfix.charAt(0);
+    private static Point decodeExtension(final int y, final int x, final int dividerx4, final int dividery, final String extrapostfix, final int lon_offset4) {
+        final double dividerx = dividerx4 / 4;
+        double processor = 1;
+        double lon32 = 0;
+        double lat32 = 0;
+        boolean odd = false;
+        int idx = 0;
+        // decode up to 8 characters
+        final int len = extrapostfix.length() > 8 ? 8 : extrapostfix.length();
+        while (idx < len) {
+            int c1 = (int) extrapostfix.charAt(idx++);
             c1 = DECODE_CHARS[c1];
             if (c1 < 0 || c1 == 30) {
                 return Point.undefined();
             }
             final int y1 = c1 / 5;
             final int x1 = c1 % 5;
-            int c2 = (extrapostfix.length() == 2) ? (int) extrapostfix.charAt(1) : 72;
-            c2 = DECODE_CHARS[c2];
-            if (c2 < 0 || c2 == 30) {
-                return Point.undefined();
+            final int y2;
+            final int x2;
+            if (idx < len) {
+                int c2 = (int) extrapostfix.charAt(idx++);
+                c2 = DECODE_CHARS[c2];
+                if (c2 < 0 || c2 == 30) {
+                    return Point.undefined();
+                }
+                y2 = c2 / 6;
+                x2 = c2 % 6;
+            } else {
+                odd = true;
+                y2 = 0;
+                x2 = 0;
             }
-            final int y2 = c2 / 6;
-            final int x2 = c2 % 6;
 
-            final int extrax = ((((x1 * 12) + (2 * x2) + 1) * dividerx4) + 120) / 240;
-            final int extray = ((((y1 * 10) + (2 * y2) + 1) * dividery) + 30) / 60;
-
-            return Point.fromMicroDeg(y + (extray * ydirection), x + extrax);
+            processor *= 30;
+            lon32 = lon32 * 30 + (x1 * 6) + x2;
+            lat32 = lat32 * 30 + (y1 * 5) + y2;
         }
-        return Point.fromMicroDeg(y + ((dividery / 2) * ydirection), x + (dividerx4 / 8));
+
+        double lat = y + ((lat32 * dividery) / processor);
+        double lon = x + ((lon32 * dividerx) / processor) + ( lon_offset4 / 4.0 );
+
+        /* FORCE_RECODE : TO DO!
+        var range = {minlon:lon, maxlon:lon, minlat:lat, maxlat:lat};
+        if (odd) {
+            range.maxlon += (dividerx / (processor / 6));
+            range.maxlat += (dividery / (processor / 5));
+        } else {
+            range.maxlon += (dividerx / processor);
+            range.maxlat += (dividery / processor);
+        } // FORCE_RECODE */
+
+        if (odd) {
+            lon += (dividerx / (2 * (processor / 6)));
+            lat += (dividery / (2 * (processor / 5)));
+        } else {
+            lon += (dividerx / (2 * processor));
+            lat += (dividery / (2 * processor));
+        } // not odd
+
+        return Point.fromDeg( lat / 1000000.0, lon / 1000000.0 );
     }
 }

src/main/java/com/mapcode/Encoder.java

@@ -105,7 +105,7 @@ private static List<Mapcode> encode(final double argLatDeg, final double argLonD
 
                     if (!isRecursive) {
                         stateOverride = currentEncodeTerritory;
-                        results.addAll(encode(latDeg, lonDeg, currentEncodeTerritory.getParentTerritory(), true, limitToOneResult,
+                        results.addAll(encode(argLatDeg, argLonDeg, currentEncodeTerritory.getParentTerritory(), true, limitToOneResult,
                                 allowWorld, stateOverride));
                         stateOverride = null;
                     }
@@ -151,15 +151,36 @@ private static List<Mapcode> encode(final double argLatDeg, final double argLonD
         return results;
     }
 
-    private static String encodeExtension(final int extrax4, final int extray, final int dividerx4, final int dividery) {
-        final int gx = ((30 * extrax4) / dividerx4);
-        final int gy = ((30 * extray) / dividery);
-        final int x1 = (gx / 6);
-        final int y1 = (gy / 5);
-        String s = "-" + ENCODE_CHARS[((y1 * 5) + x1)];
-        final int x2 = (gx % 6);
-        final int y2 = (gy % 5);
-        s += ENCODE_CHARS[((y2 * 6) + x2)];
+    private static String encodeExtension(final int extrax4, final int extray, final int dividerx4, final int dividery, final int ydirection) {
+        int extraDigits = 8; // always generate 8 digits
+        final double MAX_PRECISION_FACTOR = 810000; // 30^4 (correct for 8 precision digits)
+
+        final double encfraclon = 0; // TODO @@@ should be the fraction (of millionths)
+        final double encfraclat = 0; // TODO @@@
+
+        double factorx = MAX_PRECISION_FACTOR * dividerx4;
+        double factory = MAX_PRECISION_FACTOR * dividery;
+        double valx = (MAX_PRECISION_FACTOR * extrax4) + encfraclon;
+        double valy = (MAX_PRECISION_FACTOR * extray ) + (ydirection * encfraclat);
+
+        String s = "-";
+
+        while (true) {
+            factorx /= 30;
+            final int gx = (int)(valx / factorx);
+          
+            factory /= 30;
+            final int gy = (int)(valy / factory);
+
+            s += ENCODE_CHARS[((gy / 5) * 5) + (gx / 6)];
+            if (--extraDigits == 0) break;
+
+            s += ENCODE_CHARS[(((gy % 5) * 6) + (gx % 6))];
+            if (--extraDigits == 0) break;
+
+            valx -= factorx * gx;
+            valy -= factory * gy;
+        }
         return s;
     }
 
@@ -258,7 +279,7 @@ else if (codexm == 14) {
             result = result.charAt(0) + "." + result.charAt(1) + result.substring(3);
         }
 
-        result += encodeExtension(extrax << 2, extray, dividerx << 2, dividery); // grid
+        result += encodeExtension(extrax << 2, extray, dividerx << 2, dividery, 1); // grid
 
         return Data.headerLetter(m) + result;
     }
@@ -317,7 +338,7 @@ private static String encodeAutoHeader(final Point pointToEncode, final int this
                 autoheader_result.append(encodeTriple(vx % 168, vy % 176));
 
                 autoheader_result.append(
-                        encodeExtension(extrax << 2, extray, dividerx << 2, dividery)); // for encodeAutoHeader
+                        encodeExtension(extrax << 2, extray, dividerx << 2, dividery, -1)); // for encodeAutoHeader
                 return autoheader_result.toString();
             }
 
@@ -407,7 +428,7 @@ private static String encodeNameless(final Point pointToEncode, final int index,
                 result = result.substring(0, 3) + '.' + result.substring(3);
             }
         }
-        result += encodeExtension(extrax4, extray, dividerx4, dividery); // for encodeNameless
+        result += encodeExtension(extrax4, extray, dividerx4, dividery, -1); // for encodeNameless
 
         return result;
     }