pointers pointers pointers

Makefile

@@ -1,9 +1,14 @@
 CXX=g++ -std=c++11
 
 CAPNP_SOURCES=\
+	src/capnp/ListPointer.java\
 	src/capnp/PointerReader.java\
 	src/capnp/SegmentReader.java\
-	src/capnp/StructReader.java
+	src/capnp/StructReader.java\
+	src/capnp/Text.java\
+	src/capnp/WireHelpers.java\
+	src/capnp/WirePointer.java\
+	src/capnp/WordPointer.java
 
 CAPNPC_JAVA_SOURCES=src/compiler/capnpc-java.c++
 

src/capnp/ListPointer.java

@@ -0,0 +1,14 @@
+package capnp;
+
+import java.nio.ByteBuffer;
+
+class ListPointer extends WirePointer {
+
+    public ListPointer(ByteBuffer buffer, int buffer_offset) {
+        super(buffer, buffer_offset);
+    }
+
+    public int elementCount() {
+        return this.buffer.getInt(buffer_offset * 2) >> 3;
+    }
+}

src/capnp/Text.java

@@ -0,0 +1,29 @@
+package capnp;
+
+import java.nio.ByteBuffer;
+
+public class Text {
+
+    public static class Reader {
+        public final ByteBuffer buffer;
+        public final int offset; // in bytes
+        public final int size; // in bytes
+
+        public Reader(ListPointer ptr) {
+            this.buffer = ptr.buffer;
+            this.offset = ptr.buffer_offset * 8;
+            this.size = ptr.elementCount();
+        }
+
+        public String toString() {
+            byte[] bytes = new byte[this.size];
+            buffer.get(bytes, this.offset, this.size);
+            try {
+                return new String(bytes, "UTF-8");
+            } catch(java.io.UnsupportedEncodingException e) {
+                return "unsupported encoding"; // XXX
+            }
+        }
+    }
+
+}

src/capnp/WireHelpers.java

@@ -0,0 +1,10 @@
+package capnp;
+
+class WireHelpers {
+    public static Text.Reader readTextPointer(SegmentReader segment,
+                                         WirePointer ref) {
+        ref.target();
+        ListPointer listPtr = (ListPointer)ref;
+        return new Text.Reader(listPtr);
+    }
+}

src/capnp/WirePointer.java

@@ -0,0 +1,32 @@
+package capnp;
+
+import java.nio.ByteBuffer;
+
+class WirePointer {
+    public final ByteBuffer buffer;
+    public final int buffer_offset; // in words
+
+    public final byte STRUCT = 0;
+    public final byte LIST = 1;
+    public final byte FAR = 2;
+    public final byte OTHER = 3;
+
+    public WirePointer(ByteBuffer buffer, int offset) {
+        this.buffer = buffer;
+        this.buffer_offset = offset;
+    }
+
+    public int offset_and_kind() {
+        return this.buffer.getInt(buffer_offset * 2);
+    }
+
+    public byte kind() {
+        return (byte) (this.offset_and_kind() & 3);
+    }
+
+    public WordPointer target() {
+        return new WordPointer(buffer,
+                               1 + (this.offset_and_kind() >> 2));
+
+    }
+}

src/capnp/WordPointer.java

@@ -0,0 +1,13 @@
+package capnp;
+
+import java.nio.ByteBuffer;
+
+class WordPointer {
+    public final ByteBuffer buffer;
+    public final int offset; // in words
+
+    public WordPointer(ByteBuffer buffer, int offset) {
+        this.buffer = buffer;
+        this.offset = offset;
+    }
+}