[mkgmap-dev] [PATCH] Add a substring filter to the style language.

Mon Mar 15 16:51:04 GMT 2010

This can be used to extract substrings from values.  If the "name" tag on an object was
equal to "abcdef":

'${name|substring:2}' => 'cdef'
'${name|substring:2:4}' => 'cd'

As an example, it can be used to clean up the "ref" element on route relations:

type=route & route=road & network=US:I & ref ~ 'I\d+' { apply { set route_network='US:I'; set route_ref='${ref|substring:1}'; } }
type=route & route=road & network=US:I & ref ~ 'I \d+' { apply { set route_network='US:I'; set route_ref='${ref|substring:2}'; } }
type=route & route=road & network=US:I & ref ~ 'I-\d+' { apply { set route_network='US:I'; set route_ref='${ref|substring:2}'; } }
type=route & route=road & network=US:I & ref ~ '\d+' { apply { set route_network='US:I'; set route_ref='${ref}'; } }
---
 .../mkgmap/osmstyle/actions/SubstringFilter.java   |   66 ++++++++++++++++++++
 .../mkgmap/osmstyle/actions/ValueBuilder.java      |    2 +
 2 files changed, 68 insertions(+), 0 deletions(-)
 create mode 100644 src/uk/me/parabola/mkgmap/osmstyle/actions/SubstringFilter.java

diff --git a/src/uk/me/parabola/mkgmap/osmstyle/actions/SubstringFilter.java b/src/uk/me/parabola/mkgmap/osmstyle/actions/SubstringFilter.java
new file mode 100644
index 0000000..823d402
--- /dev/null
+++ b/src/uk/me/parabola/mkgmap/osmstyle/actions/SubstringFilter.java
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2010 Jeffrey C. Ollie
+ * 
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 as
+ *  published by the Free Software Foundation.
+ * 
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ * 
+ * 
+ * Author: Jeffrey C. Ollie
+ * Create date: 08-March-2010
+ */
+package uk.me.parabola.mkgmap.osmstyle.actions;
+
+import uk.me.parabola.mkgmap.reader.osm.Element;
+
+/**
+ * Extract a substring from a value
+ *
+ * @author Jeffrey C. Ollie
+ */
+public class SubstringFilter extends ValueFilter {
+    private int args;
+    private int start;
+    private int end;
+
+    public SubstringFilter(String arg) {
+	start = 0;
+	end = 0;
+	args = 0;
+
+	String[] temp = arg.split(":");
+
+	try {
+	    if (temp.length == 1) {
+		start = Integer.parseInt(temp[0]);
+		args = 1;
+	    } else if (temp.length == 2) {
+		start = Integer.parseInt(temp[0]);
+		end = Integer.parseInt(temp[1]);
+		args = 2;
+	    } else {
+		start = 0;
+		end = 0;
+		args = 0;
+	    }
+	} catch (NumberFormatException e) {
+	}
+    }
+
+    protected String doFilter(String value, Element el) {
+	if (value == null) return null;
+
+	if (args == 1) {
+	    return value.substring(start);
+	}
+	if (args == 2) {
+	    return value.substring(start, end);
+	}
+	return value;
+    }
+}
diff --git a/src/uk/me/parabola/mkgmap/osmstyle/actions/ValueBuilder.java b/src/uk/me/parabola/mkgmap/osmstyle/actions/ValueBuilder.java
index 27b861d..1100b15 100644
--- a/src/uk/me/parabola/mkgmap/osmstyle/actions/ValueBuilder.java
+++ b/src/uk/me/parabola/mkgmap/osmstyle/actions/ValueBuilder.java
@@ -171,6 +171,8 @@ public class ValueBuilder {
 			item.addFilter(new HeightFilter(arg));
 		} else if (cmd.equals("not-equal")) {
 			item.addFilter(new NotEqualFilter(arg));
+		} else if (cmd.equals("substring")) {
+			item.addFilter(new SubstringFilter(arg));
 		}
 	}
 
-- 
1.7.0.1


