amqp_0_10: Encoding for packed structs.

git-svn-id: https://svn.apache.org/repos/asf/incubator/qpid/trunk/qpid@646943 13f79535-47bb-0310-9956-ffa450edef68

4 files changed, 40 insertions, 25 deletions

diff --git a/cpp/src/qpid/amqp_0_10/Packer.h b/cpp/src/qpid/amqp_0_10/Packer.h
index 8943dc4c51..90d72408b5 100644
--- a/cpp/src/qpid/amqp_0_10/Packer.h
+++ b/cpp/src/qpid/amqp_0_10/Packer.h
@@ -24,6 +24,7 @@
 
 #include <boost/optional.hpp>
 #include <boost/none.hpp>
+#include "qpid/amqp_0_10/built_in_types.h"
 
 namespace qpid {
 namespace amqp_0_10 {
@@ -60,17 +61,21 @@ class PackBits {
   public:
     PackBits() : bit(1), bits(0) {}
 
-    void setBit() { bits |= bit; bit <<= 1; }
-    void skipBit() { bit <<= 1; }
-
+    void setBit(bool b) { if (b) bits |= bit; bit <<= 1; }
     uint32_t getBits() { return bits; }
-    
-    template <class T> PackBits& operator()(const T&) { setBit(); return *this; }
 
+    /** The bit is always set for non-optional values. */
+    template <class T>
+    PackBits& operator()(const T&) { setBit(1); return *this; }
+
+    /** For optional values the bit is set if the value is present. */
     template <class T> PackBits& operator()(const boost::optional<T>& opt) {
-        opt ? setBit() : skipBit(); return *this;
+        setBit(opt); return *this;
     }
 
+    /** Bits are special optional values */
+    PackBits& operator()(Bit b) { setBit(b); return *this; }
+    
   private:
     uint32_t bit;
     uint32_t bits;
@@ -83,12 +88,23 @@ template<class T> uint32_t packBits(const T& t) {
     return pack.getBits();
 }
 
+/** Decode members enabled by Bits */
 template <class Decoder, class Bits>
 class PackedDecoder {
   public:
     PackedDecoder(Decoder& d, Bits b) : decode(d), bits(b) {}
 
-    template <class T> PackedDecoder& operator()(T& t) { decode(t); return *this; }
+    template <class T> PackedDecoder& operator()(T& t) {
+        if (bits & 1)
+            decode(t);
+        else
+            t = T();
+        // FIXME aconway 2008-04-10: When we have all optionals
+        // represented by boost::optional the line above should be:
+        // throw CommandInvalidException("A required value was omitted.");
+        bits >>= 1;
+        return *this;
+    }
     
     template <class T> PackedDecoder& operator()(boost::optional<T>& opt) {
         if (bits & 1) {
diff --git a/cpp/src/qpid/amqp_0_10/built_in_types.h b/cpp/src/qpid/amqp_0_10/built_in_types.h
index 5b79faef36..dccb6a4785 100644
--- a/cpp/src/qpid/amqp_0_10/built_in_types.h
+++ b/cpp/src/qpid/amqp_0_10/built_in_types.h
@@ -61,14 +61,17 @@ inline std::ostream& operator<<(std::ostream& o, const Wrapper<T>& w) {
 struct Void { template <class S> void serialize(S&) {} };
 inline std::ostream& operator<<(std::ostream& o, const Void&) { return o; } 
 
-/** Bit type - bool value with no encoding. */
-struct  Bit : Wrapper<bool> {
-    template <class S> void serialize(S& s) { s.split(*this); }
-    template <class S> void encode(S&) const {}
-    template <class S> void decode(S&) { value=true; }
+/** Bit is a presence indicator - an optional value with no encoding. */
+struct Bit : public Wrapper<bool> {
+    Bit(bool b=false) : Wrapper<bool>(b) {}
+    using Wrapper<bool>::operator=;
+    template <class S> void serialize(S& s) { s.split(*this); } 
+    template <class S> void encode(S&) const { }
+    template <class S> void decode(S&) { *this = true; }
 };
+
 inline std::ostream& operator<<(std::ostream& o, const Bit& b) {
-    return o << b.value;
+    return o << bool(b);
 }
 
 // Fixed size types
diff --git a/cpp/src/qpid/amqp_0_10/complex_types.cpp b/cpp/src/qpid/amqp_0_10/complex_types.cpp
index 93550b9c20..78ddfeb026 100644
--- a/cpp/src/qpid/amqp_0_10/complex_types.cpp
+++ b/cpp/src/qpid/amqp_0_10/complex_types.cpp
@@ -21,7 +21,7 @@
 
 #include "qpid/amqp_0_10/ApplyCommand.h"
 #include "qpid/amqp_0_10/ApplyControl.h"
-// FIXME aconway 2008-03-04:  #include "qpid/amqp_0_10/ApplyStruct.h"
+#include "qpid/amqp_0_10/ApplyStruct.h"
 #include "qpid/amqp_0_10/apply.h"
 #include <iostream>
 
@@ -52,15 +52,11 @@ uint8_t Control::getClassCode() const { return apply(GetClassCode(), *this); }
 const char* Control::getName() const { return apply(GetName(), *this); }
 const char* Control::getClassName() const { return apply(GetClassName(), *this); }
 
-// FIXME aconway 2008-03-04: Struct visitors
-// uint8_t Struct::getCode() const { return apply(GetCode(), *this); }
-// uint8_t Struct::getPack() const { return apply(GetPack(), *this); }
-// uint8_t Struct::getSize() const { return apply(GetSize(), *this); }
-// uint8_t Struct::getClassCode() const { return apply(GetClassCode(), *this); }
-uint8_t Struct::getCode() const { assert(0); return 0; }
-uint8_t Struct::getPack() const { assert(0); return 0; }
-uint8_t Struct::getSize() const { assert(0); return 0; }
-uint8_t Struct::getClassCode() const { assert(0); return 0; }
+
+uint8_t Struct::getCode() const { return apply(GetCode(), *this); }
+uint8_t Struct::getPack() const { return apply(GetPack(), *this); }
+uint8_t Struct::getSize() const { return apply(GetSize(), *this); }
+uint8_t Struct::getClassCode() const { return apply(GetClassCode(), *this); }
 
 struct PrintVisitor {
     typedef std::ostream& result_type;
@@ -71,8 +67,7 @@ struct PrintVisitor {
 
 std::ostream& operator<<(std::ostream& o, const Command& x) { return apply(PrintVisitor(o), x); }
 std::ostream& operator<<(std::ostream& o, const Control& x) { return apply(PrintVisitor(o), x); }
-// FIXME aconway 2008-04-07: 
-// std::ostream& operator<<(std::ostream& o, const Struct& x)  { apply(PrintVisitor(o), x); }
+std::ostream& operator<<(std::ostream& o, const Struct& x)  { return apply(PrintVisitor(o), x); }
     
 }} // namespace qpid::amqp_0_10
 
diff --git a/cpp/src/qpid/amqp_0_10/complex_types.h b/cpp/src/qpid/amqp_0_10/complex_types.h
index c8080b867d..5d327cc46e 100644
--- a/cpp/src/qpid/amqp_0_10/complex_types.h
+++ b/cpp/src/qpid/amqp_0_10/complex_types.h
@@ -90,6 +90,7 @@ struct Control
 };
 std::ostream& operator<<(std::ostream&, const Control&);
 
+// Note: only coded structs inherit from Struct.
 struct StructVisitor;
 struct ConstStructVisitor;
 struct StructHolder;