Fix AnyStruct::getPointerSection(), which was totally broken and not tested.

c++/src/capnp/any-test.c++

@@ -162,6 +162,20 @@ TEST(Any, AnyStruct) {
     // TODO: is there a higher-level API for this?
     memcpy(sb.getDataSection().begin(), r.getDataSection().begin(), r.getDataSection().size());
   }
+
+  {
+    auto ptrs = r.getPointerSection();
+    EXPECT_EQ("foo", ptrs[0].getAs<Text>());
+    EXPECT_EQ("bar", kj::heapString(ptrs[1].getAs<Data>().asChars()));
+    EXPECT_EQ("xyzzy", ptrs[15].getAs<List<Text>>()[1]);
+  }
+
+  {
+    auto ptrs = b.getPointerSection();
+    EXPECT_EQ("foo", ptrs[0].getAs<Text>());
+    EXPECT_EQ("bar", kj::heapString(ptrs[1].getAs<Data>().asChars()));
+    EXPECT_EQ("xyzzy", ptrs[15].getAs<List<Text>>()[1]);
+  }
 }
 
 TEST(Any, AnyList) {

c++/src/capnp/any.h

@@ -574,7 +574,7 @@ public:
   inline uint size() { return _reader.size() / ELEMENTS; }
 
   template <typename T> ReaderFor<T> as() {
-  // T must be List<U>.
+    // T must be List<U>.
     return ReaderFor<T>(_reader);
   }
 private:
@@ -599,7 +599,7 @@ public:
   inline uint size() { return _builder.size() / ELEMENTS; }
 
   template <typename T> BuilderFor<T> as() {
-  // T must be List<U>.
+    // T must be List<U>.
     return BuilderFor<T>(_builder);
   }
 

c++/src/capnp/layout.h

@@ -826,7 +826,7 @@ inline Data::Builder StructBuilder::getDataSectionAsBlob() {
 }
 
 inline _::ListBuilder StructBuilder::getPointerSectionAsList() {
-  return _::ListBuilder(segment, pointers, pointerCount * BITS_PER_POINTER / ELEMENTS,
+  return _::ListBuilder(segment, pointers, 1 * POINTERS * BITS_PER_POINTER / ELEMENTS,
                         pointerCount * (1 * ELEMENTS / POINTERS),
                         0 * BITS, 1 * POINTERS, ElementSize::POINTER);
 }
@@ -911,8 +911,8 @@ inline Data::Reader StructReader::getDataSectionAsBlob() {
 
 inline _::ListReader StructReader::getPointerSectionAsList() {
   return _::ListReader(segment, pointers, pointerCount * (1 * ELEMENTS / POINTERS),
-                       pointerCount * BITS_PER_POINTER / ELEMENTS,
-                       0 * BITS, 1 * POINTERS, ElementSize::POINTER, nestingLimit);
+                       1 * POINTERS * BITS_PER_POINTER / ELEMENTS, 0 * BITS, 1 * POINTERS,
+                       ElementSize::POINTER, nestingLimit);
 }
 
 template <typename T>