some methods for StructReader

src/capnp/PointerReader.java

@@ -2,6 +2,22 @@ package capnp;
 
 public class PointerReader {
     public SegmentReader segment;
-    public long pointer;
+    public int pointer; // word offset
     public int nestingLimit;
+
+    public PointerReader() {
+        this.segment = null;
+        this.pointer = 0; // XXX
+        this.nestingLimit = 0x7fffffff;
+    }
+
+    public PointerReader(SegmentReader segment, int pointer, int nestingLimit) {
+        this.segment = segment;
+        this.pointer = pointer;
+        this.nestingLimit = nestingLimit;
+    }
+
+    public void getText() {
+        throw new Error();
+    }
 }

src/capnp/StructReader.java

@@ -2,16 +2,51 @@ package capnp;
 
 public class StructReader {
     public SegmentReader segment;
-    public long data; //byte offset to data section
+    public int data; //byte offset to data section
 
-    // public WirePointer pointers;
+    public int pointers; // word offset of pointer section
     public int dataSize; // in bits
     public short pointerCount;
-    public short bit0Offset;
+    public byte bit0Offset;
     public int nestingLimit;
 
 
-    public <T> T getDataField() {
-        throw new Error();
+    public boolean getBoolField(int offset) {
+        // XXX should use unsigned operations
+        if (offset < this.dataSize) {
+            if (offset == 0) {
+                offset = this.bit0Offset;
+            }
+            byte b = this.segment.ptr.get(offset / 8);
+            return (b & (1 << (offset % 8))) != 0;
+        } else {
+            return false;
+        }
+    }
+
+    public byte getByteField(int offset) {
+        if ((offset + 1) * 8 <= this.dataSize) {
+            return this.segment.ptr.get(this.data + offset);
+        } else {
+            return 0;
+        }
+    }
+
+    public int getIntField(int offset) {
+        if ((offset + 1) * 32 <= this.dataSize) {
+            return this.segment.ptr.getInt((this.data / 4) + offset);
+        } else {
+            return 0;
+        }
+    }
+
+    public PointerReader getPointerField(int ptrIndex) {
+        if (ptrIndex < this.pointerCount) {
+            return new PointerReader(this.segment,
+                                     this.pointers + ptrIndex,
+                                     this.nestingLimit);
+        } else {
+            return new PointerReader();
+        }
     }
 }