From 50eb62361daca00b9838e3e3effccdc79542ea6f Mon Sep 17 00:00:00 2001
From: afischerdev <afischer@dbserv.de>
Date: Mon, 6 Nov 2023 12:06:43 +0100
Subject: [PATCH] rename RasterCoder

---
 .../mapcreator/ElevationRasterCoder.java      | 117 ++++++++++++++++++
 1 file changed, 117 insertions(+)
 create mode 100644 brouter-map-creator/src/main/java/btools/mapcreator/ElevationRasterCoder.java

diff --git a/brouter-map-creator/src/main/java/btools/mapcreator/ElevationRasterCoder.java b/brouter-map-creator/src/main/java/btools/mapcreator/ElevationRasterCoder.java
new file mode 100644
index 0000000..02a841d
--- /dev/null
+++ b/brouter-map-creator/src/main/java/btools/mapcreator/ElevationRasterCoder.java
@@ -0,0 +1,117 @@
+package btools.mapcreator;
+
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+import btools.util.MixCoderDataInputStream;
+import btools.util.MixCoderDataOutputStream;
+
+//
+// Encode/decode a raster
+//
+
+public class ElevationRasterCoder {
+  public void encodeRaster(ElevationRaster raster, OutputStream os) throws IOException {
+    DataOutputStream dos = new DataOutputStream(os);
+
+    long t0 = System.currentTimeMillis();
+
+    dos.writeInt(raster.ncols);
+    dos.writeInt(raster.nrows);
+    dos.writeBoolean(raster.halfcol);
+    dos.writeDouble(raster.xllcorner);
+    dos.writeDouble(raster.yllcorner);
+    dos.writeDouble(raster.cellsize);
+    dos.writeShort(raster.noDataValue);
+
+    _encodeRaster(raster, os);
+    long t1 = System.currentTimeMillis();
+
+    System.out.println("finished encoding in " + (t1 - t0) + " ms");
+  }
+
+  public ElevationRaster decodeRaster(InputStream is) throws IOException {
+    DataInputStream dis = new DataInputStream(is);
+
+    long t0 = System.currentTimeMillis();
+
+    ElevationRaster raster = new ElevationRaster();
+    raster.ncols = dis.readInt();
+    raster.nrows = dis.readInt();
+    raster.halfcol = dis.readBoolean();
+    raster.xllcorner = dis.readDouble();
+    raster.yllcorner = dis.readDouble();
+    raster.cellsize = dis.readDouble();
+    raster.noDataValue = dis.readShort();
+    raster.eval_array = new short[raster.ncols * raster.nrows];
+
+    _decodeRaster(raster, is);
+
+    raster.usingWeights = false; // raster.ncols > 6001;
+
+    long t1 = System.currentTimeMillis();
+    System.out.println("finished decoding in " + (t1 - t0) + " ms ncols=" + raster.ncols + " nrows=" + raster.nrows);
+    return raster;
+  }
+
+
+  private void _encodeRaster(ElevationRaster raster, OutputStream os) throws IOException {
+    MixCoderDataOutputStream mco = new MixCoderDataOutputStream(os);
+    int nrows = raster.nrows;
+    int ncols = raster.ncols;
+    short[] pixels = raster.eval_array;
+    int colstep = raster.halfcol ? 2 : 1;
+
+    for (int row = 0; row < nrows; row++) {
+      short lastval = Short.MIN_VALUE; // nodata
+      for (int col = 0; col < ncols; col += colstep) {
+        short val = pixels[row * ncols + col];
+        if (val == -32766) {
+          val = lastval; // replace remaining (border) skips
+        } else {
+          lastval = val;
+        }
+
+        // remap nodata
+        int code = val == Short.MIN_VALUE ? -1 : (val < 0 ? val - 1 : val);
+        mco.writeMixed(code);
+      }
+    }
+    mco.flush();
+  }
+
+  private void _decodeRaster(ElevationRaster raster, InputStream is) throws IOException {
+    MixCoderDataInputStream mci = new MixCoderDataInputStream(is);
+    int nrows = raster.nrows;
+    int ncols = raster.ncols;
+    short[] pixels = raster.eval_array;
+    int colstep = raster.halfcol ? 2 : 1;
+
+    for (int row = 0; row < nrows; row++) {
+      for (int col = 0; col < ncols; col += colstep) {
+        int code = mci.readMixed();
+
+        // remap nodata
+        int v30 = code == -1 ? Short.MIN_VALUE : (code < 0 ? code + 1 : code);
+        if (raster.usingWeights && v30 > -32766) {
+          v30 *= 2;
+        }
+        pixels[row * ncols + col] = (short) (v30);
+      }
+      if (raster.halfcol) {
+        for (int col = 1; col < ncols - 1; col += colstep) {
+          int l = (int) pixels[row * ncols + col - 1];
+          int r = (int) pixels[row * ncols + col + 1];
+          short v30 = Short.MIN_VALUE; // nodata
+          if (l > -32766 && r > -32766) {
+            v30 = (short) ((l + r) / 2);
+          }
+          pixels[row * ncols + col] = v30;
+        }
+      }
+    }
+  }
+}