QPID-4974 - Generalized the mechanisms for composing and parsing AMQP-encoded fields.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1499115 13f79535-47bb-0310-9956-ffa450edef68

10 files changed, 762 insertions, 340 deletions

diff --git a/qpid/extras/dispatch/CMakeLists.txt b/qpid/extras/dispatch/CMakeLists.txt
index fb62be2eeb..e0dbfcfc3f 100644
--- a/qpid/extras/dispatch/CMakeLists.txt
+++ b/qpid/extras/dispatch/CMakeLists.txt
@@ -86,6 +86,7 @@ set(server_SOURCES
     src/iterator.c
     src/log.c
     src/message.c
+    src/parse.c
     src/posix/threading.c
     src/python_embedded.c
     src/router_node.c
diff --git a/qpid/extras/dispatch/include/qpid/dispatch/amqp.h b/qpid/extras/dispatch/include/qpid/dispatch/amqp.h
new file mode 100644
index 0000000000..9babeb930d
--- /dev/null
+++ b/qpid/extras/dispatch/include/qpid/dispatch/amqp.h
@@ -0,0 +1,80 @@
+#ifndef __dispatch_amqp_h__
+#define __dispatch_amqp_h__ 1
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * 
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/**
+ * AMQP Performative Tags
+ */
+#define DX_PERFORMATIVE_HEADER                  0x70
+#define DX_PERFORMATIVE_DELIVERY_ANNOTATIONS    0x71
+#define DX_PERFORMATIVE_MESSAGE_ANNOTATIONS     0x72  
+#define DX_PERFORMATIVE_PROPERTIES              0x73
+#define DX_PERFORMATIVE_APPLICATION_PROPERTIES  0x74
+#define DX_PERFORMATIVE_BODY_DATA               0x75
+#define DX_PERFORMATIVE_BODY_AMQP_SEQUENCE      0x76
+#define DX_PERFORMATIVE_BODY_AMQP_VALUE         0x77
+#define DX_PERFORMATIVE_FOOTER                  0x78
+
+
+/**
+ * AMQP Type Tags
+ */
+#define DX_AMQP_NULL        0x40
+#define DX_AMQP_BOOLEAN     0x56
+#define DX_AMQP_TRUE        0x41
+#define DX_AMQP_FALSE       0x42
+#define DX_AMQP_UBYTE       0x50
+#define DX_AMQP_USHORT      0x60
+#define DX_AMQP_UINT        0x70
+#define DX_AMQP_SMALLUINT   0x52
+#define DX_AMQP_UINT0       0x43
+#define DX_AMQP_ULONG       0x80
+#define DX_AMQP_SMALLULONG  0x53
+#define DX_AMQP_ULONG0      0x44
+#define DX_AMQP_BYTE        0x51
+#define DX_AMQP_SHORT       0x61
+#define DX_AMQP_INT         0x71
+#define DX_AMQP_SMALLINT    0x54
+#define DX_AMQP_LONG        0x81
+#define DX_AMQP_SMALLLONG   0x55
+#define DX_AMQP_FLOAT       0x72
+#define DX_AMQP_DOUBLE      0x82
+#define DX_AMQP_DECIMAL32   0x74
+#define DX_AMQP_DECIMAL64   0x84
+#define DX_AMQP_DECIMAL128  0x94
+#define DX_AMQP_UTF32       0x73
+#define DX_AMQP_TIMESTAMP   0x83
+#define DX_AMQP_UUID        0x98
+#define DX_AMQP_VBIN8       0xa0
+#define DX_AMQP_VBIN32      0xb0
+#define DX_AMQP_STR8_UTF8   0xa1
+#define DX_AMQP_STR32_UTF8  0xb1
+#define DX_AMQP_SYM8        0xa3
+#define DX_AMQP_SYM32       0xb3
+#define DX_AMQP_LIST0       0x45
+#define DX_AMQP_LIST8       0xc0
+#define DX_AMQP_LIST32      0xd0
+#define DX_AMQP_MAP8        0xc1
+#define DX_AMQP_MAP32       0xd1
+#define DX_AMQP_ARRAY8      0xe0
+#define DX_AMQP_ARRAY32     0xf0
+
+#endif
+
diff --git a/qpid/extras/dispatch/include/qpid/dispatch/compose.h b/qpid/extras/dispatch/include/qpid/dispatch/compose.h
index 514b450e58..7d668f0ac0 100644
--- a/qpid/extras/dispatch/include/qpid/dispatch/compose.h
+++ b/qpid/extras/dispatch/include/qpid/dispatch/compose.h
@@ -24,16 +24,6 @@
 
 typedef struct dx_composed_field_t dx_composed_field_t;
 
-#define DX_PERFORMATIVE_HEADER                  0x70
-#define DX_PERFORMATIVE_DELIVERY_ANNOTATIONS    0x71
-#define DX_PERFORMATIVE_MESSAGE_ANNOTATIONS     0x72  
-#define DX_PERFORMATIVE_PROPERTIES              0x73
-#define DX_PERFORMATIVE_APPLICATION_PROPERTIES  0x74
-#define DX_PERFORMATIVE_BODY_DATA               0x75
-#define DX_PERFORMATIVE_BODY_AMQP_SEQUENCE      0x76
-#define DX_PERFORMATIVE_BODY_AMQP_VALUE         0x77
-#define DX_PERFORMATIVE_FOOTER                  0x78
-
 /**
  * Begin composing a new field for a message.  The new field can be standalone or
  * appended onto an existing field.
@@ -43,7 +33,7 @@ typedef struct dx_composed_field_t dx_composed_field_t;
  *        create a standalone field.
  * @return A pointer to the newly created field.
  */
-dx_composed_field_t *dx_compose(uint8_t performative, dx_composed_field_t *extend);
+dx_composed_field_t *dx_compose(uint64_t performative, dx_composed_field_t *extend);
 
 /**
  * Free the resources associated with a composed field.
diff --git a/qpid/extras/dispatch/include/qpid/dispatch/iterator.h b/qpid/extras/dispatch/include/qpid/dispatch/iterator.h
index 2412995432..5269abd4b2 100644
--- a/qpid/extras/dispatch/include/qpid/dispatch/iterator.h
+++ b/qpid/extras/dispatch/include/qpid/dispatch/iterator.h
@@ -19,6 +19,7 @@
  * under the License.
  */
 
+#include <stdint.h>
 #include <qpid/dispatch/buffer.h>
 #include <qpid/dispatch/iovec.h>
 
@@ -132,6 +133,14 @@ unsigned char dx_field_iterator_octet(dx_field_iterator_t *iter);
 int dx_field_iterator_end(dx_field_iterator_t *iter);
 
 /**
+ * Return a sub-iterator that equals the supplied iterator except that it
+ * starts at the supplied iterator's current position.
+ */
+dx_field_iterator_t *dx_field_iterator_sub(dx_field_iterator_t *iter, uint32_t length);
+
+void dx_field_iterator_advance(dx_field_iterator_t *iter, uint32_t length);
+
+/**
  * Compare an input string to the iterator's view.  Return true iff they are equal.
  */
 int dx_field_iterator_equal(dx_field_iterator_t *iter, const unsigned char *string);
@@ -149,15 +158,14 @@ int dx_field_iterator_prefix(dx_field_iterator_t *iter, const char *prefix);
  */
 unsigned char *dx_field_iterator_copy(dx_field_iterator_t *iter);
 
-
+/**
+ * Return the contents of this iter into an iovec structure.  This is used in a
+ * scatter/gather IO mechanism.  If the iterator spans multiple physical buffers,
+ * the iovec structure will contain one pointer per buffer.
+ *
+ * @param iter A field iterator
+ * @return An iovec structure that references the data in the iterator's buffers.
+ */
 dx_iovec_t *dx_field_iterator_iovec(const dx_field_iterator_t *iter);
 
-typedef struct dx_field_map_t dx_field_map_t;
-
-dx_field_map_t *dx_field_map(dx_field_iterator_t *iter, int string_keys_only);
-void dx_field_map_free(dx_field_map_t *map);
-dx_field_iterator_t *dx_field_map_by_key(dx_field_map_t *map, const char *key);
-
-dx_field_iterator_t *dx_field_raw(dx_field_iterator_t *iter);
-
 #endif
diff --git a/qpid/extras/dispatch/include/qpid/dispatch/parse.h b/qpid/extras/dispatch/include/qpid/dispatch/parse.h
new file mode 100644
index 0000000000..087a440c4e
--- /dev/null
+++ b/qpid/extras/dispatch/include/qpid/dispatch/parse.h
@@ -0,0 +1,195 @@
+#ifndef __dispatch_parse_h__
+#define __dispatch_parse_h__ 1
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * 
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#include <qpid/dispatch/buffer.h>
+#include <qpid/dispatch/iterator.h>
+
+typedef struct dx_parsed_field_t dx_parsed_field_t;
+
+/**
+ * Parse a field delimited by a field iterator.
+ *
+ * @param iter Field iterator for the field being parsed
+ * @return A pointer to the newly created field.
+ */
+dx_parsed_field_t *dx_parse(dx_field_iterator_t *iter);
+
+/**
+ * Free the resources associated with a parsed field.
+ *
+ * @param A field pointer returned by dx_parse.
+ */
+void dx_parse_free(dx_parsed_field_t *field);
+
+/**
+ * Check to see if the field parse was successful (i.e. the field was
+ * well-formed).
+ *
+ * @param field The field pointer returned by dx_parse.
+ * @return true iff the field was well-formed and successfully parsed.
+ */
+int dx_parse_ok(dx_parsed_field_t *field);
+
+/**
+ * Return the text of the error describing the parse error if the field
+ * is not well-formed.
+ *
+ * @param field The field pointer returned by dx_parse.
+ * @return a null-terminated string describing the parse failure.
+ */
+const char *dx_parse_error(dx_parsed_field_t *field);
+
+/**
+ * Return the AMQP tag for the parsed (and well-formed) field.
+ *
+ * @param field The field pointer returned by dx_parse.
+ * @return The tag (see amqp.h) that indicates the type of the field.
+ */
+uint8_t dx_parse_tag(dx_parsed_field_t *field);
+
+/**
+ * Return an iterator for the raw content of the field.  This is useful
+ * only for scalar fields.  It is not appropriate for compound fields.
+ * For compound fields, use the sub-field functions instead.
+ *
+ * The returned iterator describes the raw content of the field, and can be
+ * used for comparison, indexing, or copying.
+ *
+ * IMPORTANT: The returned iterator is owned by the field and *must not* be
+ * freed by the caller of this function.
+ *
+ * @param field The field pointer returned by dx_parse.
+ * @return A field iterator that describes the field's raw content.
+ */
+dx_field_iterator_t *dx_parse_raw(dx_parsed_field_t *field);
+
+/**
+ * Return the raw content as an unsigned integer up to 32-bits.  This is
+ * valid only for scalar fields of a fixed size of 4-octets or fewer.
+ *
+ * @param field The field pointer returned by dx_parse.
+ * @return The raw content of the field cast as a uint32_t.
+ */
+uint32_t dx_parse_as_uint(dx_parsed_field_t *field);
+
+/**
+ * Return the raw content as an unsigned integer up to 64-bits.  This is
+ * valid only for scalar fields of a fixed size of 8-octets or fewer.
+ *
+ * @param field The field pointer returned by dx_parse.
+ * @return The raw content of the field cast as a uint64_t.
+ */
+uint64_t dx_parse_as_ulong(dx_parsed_field_t *field);
+
+/**
+ * Return the raw content as a signed integer up to 32-bits.  This is
+ * valid only for scalar fields of a fixed size of 4-octets or fewer.
+ *
+ * @param field The field pointer returned by dx_parse.
+ * @return The raw content of the field cast as an int32_t.
+ */
+int32_t dx_parse_as_int(dx_parsed_field_t *field);
+
+/**
+ * Return the raw content as a signed integer up to 64-bits.  This is
+ * valid only for scalar fields of a fixed size of 8-octets or fewer.
+ *
+ * @param field The field pointer returned by dx_parse.
+ * @return The raw content of the field cast as an int64_t.
+ */
+int64_t dx_parse_as_long(dx_parsed_field_t *field);
+
+/**
+ * Return the number of sub-field in a compound field.  If the field is
+ * a list or array, this is the number of items in the list/array.  If
+ * the field is a map, this is the number of key/value pairs in the map
+ * (i.e. half the number of actual sub-field in the map).
+ *
+ * For scalar fields, this function will return zero.
+ *
+ * @param field The field pointer returned by dx_parse.
+ * @return The number of sub-fields in the field.
+ */
+uint32_t dx_parse_sub_count(dx_parsed_field_t *field);
+
+/**
+ * Return a dx_parsed_field_t for the idx'th key in a map field.
+ * If 'field' is not a map, or idx is equal-to or greater-than the number
+ * of sub-fields in field, this function will return NULL.
+ *
+ * IMPORTANT: The pointer returned by this function remains owned by the
+ * parent field.  It *must not* be freed by the caller.
+ *
+ * @param field The field pointer returned by dx_parse.
+ * @param idx The index of the desired sub-field (in range 0..sub_count)
+ * @return A pointer to the parsed sub-field
+ */
+dx_parsed_field_t *dx_parse_sub_key(dx_parsed_field_t *field, uint32_t idx);
+
+/**
+ * Return a dx_parsed_field_t for the idx'th value in a compound field.
+ * If idx is equal-to or greater-than the number of sub-fields in field,
+ * this function will return NULL.
+ *
+ * IMPORTANT: The pointer returned by this function remains owned by the
+ * parent field.  It *must not* be freed by the caller.
+ *
+ * @param field The field pointer returned by dx_parse.
+ * @param idx The index of the desired sub-field (in range 0..sub_count)
+ * @return A pointer to the parsed sub-field
+ */
+dx_parsed_field_t *dx_parse_sub_value(dx_parsed_field_t *field, uint32_t idx);
+
+/**
+ * Convenience Function - Return true iff the field is a map.
+ *
+ * @param field The field pointer returned by dx_parse[_sub_{value,key}]
+ * @return non-zero if the condition is mat.
+ */
+int dx_parse_is_map(dx_parsed_field_t *field);
+
+/**
+ * Convenience Function - Return true iff the field is a list.
+ *
+ * @param field The field pointer returned by dx_parse[_sub_{value,key}]
+ * @return non-zero if the condition is mat.
+ */
+int dx_parse_is_list(dx_parsed_field_t *field);
+
+/**
+ * Convenience Function - Return true iff the field is a scalar type.
+ *
+ * @param field The field pointer returned by dx_parse[_sub_{value,key}]
+ * @return non-zero if the condition is mat.
+ */
+int dx_parse_is_scalar(dx_parsed_field_t *field);
+
+/**
+ * Convenience Function - Return the value for a key in a map.
+ *
+ * @param field The field pointer returned by dx_parse[_sub_{value,key}]
+ * @param key The key to search for in the map.
+ * @return The value field corresponding to the key or NULL.
+ */
+dx_parsed_field_t *dx_parse_value_by_key(dx_parsed_field_t *field, const char *key);
+
+#endif
+
diff --git a/qpid/extras/dispatch/src/agent.c b/qpid/extras/dispatch/src/agent.c
index 70f31d1522..88b2cf2bcd 100644
--- a/qpid/extras/dispatch/src/agent.c
+++ b/qpid/extras/dispatch/src/agent.c
@@ -30,6 +30,8 @@
 #include <qpid/dispatch/router.h>
 #include <qpid/dispatch/log.h>
 #include <qpid/dispatch/compose.h>
+#include <qpid/dispatch/parse.h>
+#include <qpid/dispatch/amqp.h>
 #include <string.h>
 #include <stdio.h>
 
@@ -61,13 +63,13 @@ typedef struct {
 static char *log_module = "AGENT";
 
 
-static void dx_agent_process_get(dx_agent_t *agent, dx_field_map_t *map, dx_field_iterator_t *reply_to)
+static void dx_agent_process_get(dx_agent_t *agent, dx_parsed_field_t *map, dx_field_iterator_t *reply_to)
 {
-    dx_field_iterator_t *cls = dx_field_map_by_key(map, "type");
+    dx_parsed_field_t *cls = dx_parse_value_by_key(map, "type");
     if (cls == 0)
         return;
 
-    dx_field_iterator_t    *cls_string = dx_field_raw(cls);
+    dx_field_iterator_t    *cls_string = dx_parse_raw(cls);
     const dx_agent_class_t *cls_record;
     hash_retrieve_const(agent->class_hash, cls_string, (const void**) &cls_record);
     if (cls_record == 0)
@@ -168,20 +170,39 @@ static void dx_agent_process_request(dx_agent_t *agent, dx_message_t *msg)
         return;
 
     //
-    // Try to get a map-view of the application-properties.  Exit if it is not a map-value.
+    // Try to get a map-view of the application-properties.
     //
-    dx_field_map_t *map = dx_field_map(ap, 1);
+    dx_parsed_field_t *map = dx_parse(ap);
     if (map == 0) {
         dx_field_iterator_free(ap);
         return;
     }
 
     //
+    // Exit if there was a parsing error.
+    //
+    if (!dx_parse_ok(map)) {
+        dx_log(log_module, LOG_TRACE, "Received unparsable App Properties: %s", dx_parse_error(map));
+        dx_field_iterator_free(ap);
+        dx_parse_free(map);
+        return;
+    }
+
+    //
+    // Exit if it is not a map.
+    //
+    if (!dx_parse_is_map(map)) {
+        dx_field_iterator_free(ap);
+        dx_parse_free(map);
+        return;
+    }
+
+    //
     // Get an iterator for the "operation" field in the map.  Exit if the key is not found.
     //
-    dx_field_iterator_t *operation = dx_field_map_by_key(map, "operation");
+    dx_parsed_field_t *operation = dx_parse_value_by_key(map, "operation");
     if (operation == 0) {
-        dx_field_map_free(map);
+        dx_parse_free(map);
         dx_field_iterator_free(ap);
         return;
     }
@@ -189,12 +210,11 @@ static void dx_agent_process_request(dx_agent_t *agent, dx_message_t *msg)
     //
     // Dispatch the operation to the appropriate handler
     //
-    dx_field_iterator_t *operation_string = dx_field_raw(operation);
+    dx_field_iterator_t *operation_string = dx_parse_raw(operation);
     if (dx_field_iterator_equal(operation_string, (unsigned char*) "GET"))
         dx_agent_process_get(agent, map, reply_to);
 
-    dx_field_iterator_free(operation_string);
-    dx_field_map_free(map);
+    dx_parse_free(map);
     dx_field_iterator_free(ap);
     dx_field_iterator_free(reply_to);
 }
diff --git a/qpid/extras/dispatch/src/compose.c b/qpid/extras/dispatch/src/compose.c
index f20fd53251..0f298c8217 100644
--- a/qpid/extras/dispatch/src/compose.c
+++ b/qpid/extras/dispatch/src/compose.c
@@ -20,6 +20,7 @@
 #include <qpid/dispatch/ctools.h>
 #include <qpid/dispatch/alloc.h>
 #include <qpid/dispatch/buffer.h>
+#include <qpid/dispatch/amqp.h>
 #include "message_private.h"
 #include "compose_private.h"
 #include <memory.h>
@@ -143,9 +144,9 @@ static void dx_overwrite_32(dx_field_location_t *field, uint32_t value)
 static void dx_compose_start_composite(dx_composed_field_t *field, int isMap)
 {
     if (isMap)
-        dx_insert_8(field, 0xd1);  // map32
+        dx_insert_8(field, DX_AMQP_MAP32);
     else
-        dx_insert_8(field, 0xd0);  // list32
+        dx_insert_8(field, DX_AMQP_LIST32);
 
     //
     // Push a composite descriptor on the field stack
@@ -204,7 +205,7 @@ static void dx_compose_end_composite(dx_composed_field_t *field)
 }
 
 
-dx_composed_field_t *dx_compose(uint8_t performative, dx_composed_field_t *extend)
+dx_composed_field_t *dx_compose(uint64_t performative, dx_composed_field_t *extend)
 {
     dx_composed_field_t *field = extend;
 
@@ -219,8 +220,8 @@ dx_composed_field_t *dx_compose(uint8_t performative, dx_composed_field_t *exten
         DEQ_INIT(field->fieldStack);
     }
 
-    dx_insert(field, (const uint8_t*) "\x00\x53", 2);
-    dx_insert_8(field, performative);
+    dx_insert_8(field, 0x00);
+    dx_compose_insert_ulong(field, performative);
 
     return field;
 }
@@ -270,14 +271,14 @@ void dx_compose_end_map(dx_composed_field_t *field)
 
 void dx_compose_insert_null(dx_composed_field_t *field)
 {
-    dx_insert_8(field, 0x40);
+    dx_insert_8(field, DX_AMQP_NULL);
     bump_count(field);
 }
 
 
 void dx_compose_insert_bool(dx_composed_field_t *field, int value)
 {
-    dx_insert_8(field, value ? 0x41 : 0x42);
+    dx_insert_8(field, value ? DX_AMQP_TRUE : DX_AMQP_FALSE);
     bump_count(field);
 }
 
@@ -285,12 +286,12 @@ void dx_compose_insert_bool(dx_composed_field_t *field, int value)
 void dx_compose_insert_uint(dx_composed_field_t *field, uint32_t value)
 {
     if (value == 0) {
-        dx_insert_8(field, 0x43);  // uint0
+        dx_insert_8(field, DX_AMQP_UINT0);
     } else if (value < 256) {
-        dx_insert_8(field, 0x52);  // smalluint
+        dx_insert_8(field, DX_AMQP_SMALLUINT);
         dx_insert_8(field, (uint8_t) value);
     } else {
-        dx_insert_8(field, 0x70);  // uint
+        dx_insert_8(field, DX_AMQP_UINT);
         dx_insert_32(field, value);
     }
     bump_count(field);
@@ -300,12 +301,12 @@ void dx_compose_insert_uint(dx_composed_field_t *field, uint32_t value)
 void dx_compose_insert_ulong(dx_composed_field_t *field, uint64_t value)
 {
     if (value == 0) {
-        dx_insert_8(field, 0x44);  // ulong0
+        dx_insert_8(field, DX_AMQP_ULONG0);
     } else if (value < 256) {
-        dx_insert_8(field, 0x53);  // smallulong
+        dx_insert_8(field, DX_AMQP_SMALLULONG);
         dx_insert_8(field, (uint8_t) value);
     } else {
-        dx_insert_8(field, 0x80);  // ulong
+        dx_insert_8(field, DX_AMQP_ULONG);
         dx_insert_64(field, value);
     }
     bump_count(field);
@@ -315,10 +316,10 @@ void dx_compose_insert_ulong(dx_composed_field_t *field, uint64_t value)
 void dx_compose_insert_int(dx_composed_field_t *field, int32_t value)
 {
     if (value >= -128 && value <= 127) {
-        dx_insert_8(field, 0x54);  // smallint
+        dx_insert_8(field, DX_AMQP_SMALLINT);
         dx_insert_8(field, (uint8_t) value);
     } else {
-        dx_insert_8(field, 0x71);  // int
+        dx_insert_8(field, DX_AMQP_INT);
         dx_insert_32(field, (uint32_t) value);
     }
     bump_count(field);
@@ -328,10 +329,10 @@ void dx_compose_insert_int(dx_composed_field_t *field, int32_t value)
 void dx_compose_insert_long(dx_composed_field_t *field, int64_t value)
 {
     if (value >= -128 && value <= 127) {
-        dx_insert_8(field, 0x55);  // smalllong
+        dx_insert_8(field, DX_AMQP_SMALLLONG);
         dx_insert_8(field, (uint8_t) value);
     } else {
-        dx_insert_8(field, 0x81);  // long
+        dx_insert_8(field, DX_AMQP_LONG);
         dx_insert_64(field, (uint64_t) value);
     }
     bump_count(field);
@@ -340,7 +341,7 @@ void dx_compose_insert_long(dx_composed_field_t *field, int64_t value)
 
 void dx_compose_insert_timestamp(dx_composed_field_t *field, uint64_t value)
 {
-    dx_insert_8(field, 0x83);  // timestamp
+    dx_insert_8(field, DX_AMQP_TIMESTAMP);
     dx_insert_64(field, value);
     bump_count(field);
 }
@@ -348,7 +349,7 @@ void dx_compose_insert_timestamp(dx_composed_field_t *field, uint64_t value)
 
 void dx_compose_insert_uuid(dx_composed_field_t *field, const uint8_t *value)
 {
-    dx_insert_8(field, 0x98);  // uuid
+    dx_insert_8(field, DX_AMQP_UUID);
     dx_insert(field, value, 16);
     bump_count(field);
 }
@@ -357,10 +358,10 @@ void dx_compose_insert_uuid(dx_composed_field_t *field, const uint8_t *value)
 void dx_compose_insert_binary(dx_composed_field_t *field, const uint8_t *value, uint32_t len)
 {
     if (len < 256) {
-        dx_insert_8(field, 0xa0);  // vbin8
+        dx_insert_8(field, DX_AMQP_VBIN8);
         dx_insert_8(field, (uint8_t) len);
     } else {
-        dx_insert_8(field, 0xb0);  // vbin32
+        dx_insert_8(field, DX_AMQP_VBIN32);
         dx_insert_32(field, len);
     }
     dx_insert(field, value, len);
@@ -385,10 +386,10 @@ void dx_compose_insert_binary_buffers(dx_composed_field_t *field, dx_buffer_list
     // Supply the appropriate binary tag for the length.
     //
     if (len < 256) {
-        dx_insert_8(field, 0xa0);  // vbin8
+        dx_insert_8(field, DX_AMQP_VBIN8);
         dx_insert_8(field, (uint8_t) len);
     } else {
-        dx_insert_8(field, 0xb0);  // vbin32
+        dx_insert_8(field, DX_AMQP_VBIN32);
         dx_insert_32(field, len);
     }
 
@@ -409,10 +410,10 @@ void dx_compose_insert_string(dx_composed_field_t *field, const char *value)
     uint32_t len = strlen(value);
 
     if (len < 256) {
-        dx_insert_8(field, 0xa1);  // str8-utf8
+        dx_insert_8(field, DX_AMQP_STR8_UTF8);
         dx_insert_8(field, (uint8_t) len);
     } else {
-        dx_insert_8(field, 0xb1);  // str32-utf8
+        dx_insert_8(field, DX_AMQP_STR32_UTF8);
         dx_insert_32(field, len);
     }
     dx_insert(field, (const uint8_t*) value, len);
@@ -432,10 +433,10 @@ void dx_compose_insert_string_iterator(dx_composed_field_t *field, dx_field_iter
     dx_field_iterator_reset(iter);
 
     if (len < 256) {
-        dx_insert_8(field, 0xa1);  // str8-utf8
+        dx_insert_8(field, DX_AMQP_STR8_UTF8);
         dx_insert_8(field, (uint8_t) len);
     } else {
-        dx_insert_8(field, 0xb1);  // str32-utf8
+        dx_insert_8(field, DX_AMQP_STR32_UTF8);
         dx_insert_32(field, len);
     }
 
@@ -453,10 +454,10 @@ void dx_compose_insert_symbol(dx_composed_field_t *field, const char *value)
     uint32_t len = strlen(value);
 
     if (len < 256) {
-        dx_insert_8(field, 0xa3);  // sym8
+        dx_insert_8(field, DX_AMQP_SYM8);
         dx_insert_8(field, (uint8_t) len);
     } else {
-        dx_insert_8(field, 0xb3);  // sym32
+        dx_insert_8(field, DX_AMQP_SYM32);
         dx_insert_32(field, len);
     }
     dx_insert(field, (const uint8_t*) value, len);
diff --git a/qpid/extras/dispatch/src/iterator.c b/qpid/extras/dispatch/src/iterator.c
index 3998cd9f94..43c3b755d0 100644
--- a/qpid/extras/dispatch/src/iterator.c
+++ b/qpid/extras/dispatch/src/iterator.c
@@ -25,7 +25,7 @@
 #include <stdio.h>
 #include <string.h>
 
-static const char *log_module = "FIELD";
+//static const char *log_module = "FIELD";
 
 typedef enum {
     MODE_TO_END,
@@ -47,35 +47,12 @@ struct dx_field_iterator_t {
     unsigned char       prefix;
     int                 at_prefix;
     int                 view_prefix;
-    unsigned char       tag;
 };
 
 ALLOC_DECLARE(dx_field_iterator_t);
 ALLOC_DEFINE(dx_field_iterator_t);
 
 
-typedef struct dx_field_pair_t {
-    DEQ_LINKS(struct dx_field_pair_t);
-    dx_field_iterator_t *key_iter;
-    dx_field_iterator_t *value_iter;
-} dx_field_pair_t;
-
-DEQ_DECLARE(dx_field_pair_t, dx_field_pair_list_t);
-
-ALLOC_DECLARE(dx_field_pair_t);
-ALLOC_DEFINE(dx_field_pair_t);
-
-
-struct dx_field_map_t {
-    dx_field_iterator_t  *outer;
-    int                   key_count;
-    dx_field_pair_list_t  pairs;
-};
-
-ALLOC_DECLARE(dx_field_map_t);
-ALLOC_DEFINE(dx_field_map_t);
-
-
 typedef enum {
     STATE_START,
     STATE_SLASH_LEFT,
@@ -263,7 +240,6 @@ dx_field_iterator_t* dx_field_iterator_string(const char *text, dx_iterator_view
     if (!iter)
         return 0;
 
-    iter->tag                  = 0;
     iter->start_pointer.buffer = 0;
     iter->start_pointer.cursor = (unsigned char*) text;
     iter->start_pointer.length = strlen(text);
@@ -280,7 +256,6 @@ dx_field_iterator_t *dx_field_iterator_buffer(dx_buffer_t *buffer, int offset, i
     if (!iter)
         return 0;
 
-    iter->tag                  = 0;
     iter->start_pointer.buffer = buffer;
     iter->start_pointer.cursor = dx_buffer_base(buffer) + offset;
     iter->start_pointer.length = length;
@@ -354,6 +329,33 @@ int dx_field_iterator_end(dx_field_iterator_t *iter)
 }
 
 
+dx_field_iterator_t *dx_field_iterator_sub(dx_field_iterator_t *iter, uint32_t length)
+{
+    dx_field_iterator_t *sub = new_dx_field_iterator_t();
+    if (!sub)
+        return 0;
+
+    sub->start_pointer        = iter->pointer;
+    sub->start_pointer.length = length;
+    sub->view_start_pointer   = sub->start_pointer;
+    sub->pointer              = sub->start_pointer;
+    sub->view                 = iter->view;
+    sub->mode                 = iter->mode;
+    sub->at_prefix            = 0;
+    sub->view_prefix          = 0;
+
+    return sub;
+}
+
+
+void dx_field_iterator_advance(dx_field_iterator_t *iter, uint32_t length)
+{
+    // TODO - Make this more efficient.
+    for (uint8_t idx = 0; idx < length; idx++)
+        dx_field_iterator_octet(iter);
+}
+
+
 int dx_field_iterator_equal(dx_field_iterator_t *iter, const unsigned char *string)
 {
     dx_field_iterator_reset(iter);
@@ -387,81 +389,6 @@ int dx_field_iterator_prefix(dx_field_iterator_t *iter, const char *prefix)
 }
 
 
-static dx_field_iterator_t *dx_field_parse_amqp_value(dx_field_iterator_t *iter, unsigned int *available)
-{
-    if (*available < 1)
-        return 0;
-
-    unsigned int         start = *available;
-    dx_field_iterator_t *value = new_dx_field_iterator_t();
-    value->start_pointer = iter->pointer;
-    value->view          = ITER_VIEW_ALL;
-    value->mode          = MODE_TO_END;
-    value->at_prefix     = 0;
-    value->view_prefix   = 0;
-
-    unsigned char tag = dx_field_iterator_octet(iter);
-    unsigned int  length      = 0;
-    unsigned int  length_size = 0;
-
-    (*available)--;
-
-    switch (tag & 0xF0) {
-    case 0x40: length = 0;  break;
-    case 0x50: length = 1;  break;
-    case 0x60: length = 2;  break;
-    case 0x70: length = 4;  break;
-    case 0x80: length = 8;  break;
-    case 0x90: length = 16; break;
-    case 0xA0:
-    case 0xC0:
-    case 0xE0: length_size = 1; break;
-    case 0xB0:
-    case 0xD0:
-    case 0xF0: length_size = 4; break;
-    default:
-        free_dx_field_iterator_t(value);
-        return 0;
-    }
-
-    if (*available < length_size) {
-        free_dx_field_iterator_t(value);
-        return 0;
-    }
-
-    if (length_size == 1) {
-        length = (unsigned int) dx_field_iterator_octet(iter);
-    } else if (length_size == 4) {
-        length  = ((unsigned int) dx_field_iterator_octet(iter)) << 24;
-        length += ((unsigned int) dx_field_iterator_octet(iter)) << 16;
-        length += ((unsigned int) dx_field_iterator_octet(iter)) << 8;
-        length +=  (unsigned int) dx_field_iterator_octet(iter);
-    }
-
-    if (*available < length) {
-        free_dx_field_iterator_t(value);
-        return 0;
-    }
-
-    for (unsigned int idx = 0; idx < length; idx++)
-        (void) dx_field_iterator_octet(iter);
-    (*available) -= (length + length_size);
-
-    value->start_pointer.length = start - *available;
-    value->view_start_pointer   = value->start_pointer;
-    value->pointer              = value->start_pointer;
-    value->tag                  = tag;
-
-    return value;
-}
-
-
-static int dx_tag_is_string(unsigned char tag)
-{
-    return (tag == 0xa1 || tag == 0xb1);
-}
-
-
 unsigned char *dx_field_iterator_copy(dx_field_iterator_t *iter)
 {
     int            length = 0;
@@ -484,186 +411,6 @@ unsigned char *dx_field_iterator_copy(dx_field_iterator_t *iter)
 }
 
 
-dx_field_map_t *dx_field_map(dx_field_iterator_t *iter, int string_keys_only)
-{
-    dx_field_iterator_reset(iter);
-    unsigned char tag = dx_field_iterator_octet(iter);
-
-    //
-    // If this field is not a map, return 0;
-    //
-    if (tag != 0xc1 && tag != 0xd1) {
-        dx_log(log_module, LOG_TRACE, "dx_field_map - Invalid Map, Unexpected tag: %02x", tag);
-        return 0;
-    }
-
-    //
-    // Validate the map.  Ensure the following:
-    //   - There are an even number of fields in the compound structure
-    //   - There are anough octets in the field to account for all of the contents
-    //   - The field count matches the number of fields present
-    //   - The keys are strings (if string_keys_only)
-    //
-    unsigned int length;
-    unsigned int count;
-
-    if (tag == 0xc1) {
-        length  =  (unsigned int) dx_field_iterator_octet(iter);
-        count   =  (unsigned int) dx_field_iterator_octet(iter);
-        length -= 1; // Account for the 'count' octet
-    } else {
-        length  = ((unsigned int) dx_field_iterator_octet(iter)) << 24;
-        length += ((unsigned int) dx_field_iterator_octet(iter)) << 16;
-        length += ((unsigned int) dx_field_iterator_octet(iter)) << 8;
-        length +=  (unsigned int) dx_field_iterator_octet(iter);
-
-        count   = ((unsigned int) dx_field_iterator_octet(iter)) << 24;
-        count  += ((unsigned int) dx_field_iterator_octet(iter)) << 16;
-        count  += ((unsigned int) dx_field_iterator_octet(iter)) << 8;
-        count  +=  (unsigned int) dx_field_iterator_octet(iter);
-
-        length -= 4; // Account for the 'count' octets
-    }
-
-    //
-    // The map is not valid if count is not an even number.
-    //
-    if (count & 1) {
-        dx_log(log_module, LOG_TRACE, "dx_field_map - Invalid Map, odd number of fields: %d", count);
-        return 0;
-    }
-
-    dx_field_map_t *map = new_dx_field_map_t();
-    if (!map)
-        return 0;
-
-    map->outer     = iter;
-    map->key_count = count >> 1;
-    DEQ_INIT(map->pairs);
-
-    unsigned int idx;
-    for (idx = 0; idx < map->key_count; idx++) {
-        dx_field_iterator_t *key   = dx_field_parse_amqp_value(iter, &length);
-        dx_field_iterator_t *value = dx_field_parse_amqp_value(iter, &length);
-
-        if (key == 0 || value == 0) {
-            dx_field_map_free(map);
-            return 0;
-        }
-
-        if (string_keys_only && !dx_tag_is_string(key->tag)) {
-            dx_log(log_module, LOG_TRACE, "dx_field_map - Invalid Map, key tag is not a string: %02x", key->tag);
-            dx_field_map_free(map);
-            return 0;
-        }
-
-        dx_field_pair_t *pair = new_dx_field_pair_t();
-        if (!pair) {
-            dx_field_map_free(map);
-            return 0;
-        }
-
-        DEQ_ITEM_INIT(pair);
-        pair->key_iter   = key;
-        pair->value_iter = value;
-        DEQ_INSERT_TAIL(map->pairs, pair);
-    }
-
-    return map;
-}
-
-
-void dx_field_map_free(dx_field_map_t *map)
-{
-    if (!map)
-        return;
-
-    dx_field_pair_t *pair = DEQ_HEAD(map->pairs);
-    while (pair) {
-        DEQ_REMOVE_HEAD(map->pairs);
-        free_dx_field_iterator_t(pair->key_iter);
-        free_dx_field_iterator_t(pair->value_iter);
-        free_dx_field_pair_t(pair);
-        pair = DEQ_HEAD(map->pairs);
-    }
-
-    free_dx_field_map_t(map);
-}
-
-
-dx_field_iterator_t *dx_field_map_by_key(dx_field_map_t *map, const char *key)
-{
-    dx_field_iterator_t *key_string;
-    dx_field_iterator_t *value = 0;
-    dx_field_pair_t     *pair  = DEQ_HEAD(map->pairs);
-
-    while (pair && !value) {
-        key_string = dx_field_raw(pair->key_iter);
-        if (dx_field_iterator_equal(key_string, (const unsigned char*) key))
-            value = pair->value_iter;
-        free_dx_field_iterator_t(key_string);
-        pair = DEQ_NEXT(pair);
-    }
-
-    return value;
-}
-
-
-static unsigned int dx_field_get_length(dx_field_iterator_t *iter, unsigned char tag) {
-    unsigned long length = 0;
-
-    switch (tag & 0xF0) {
-    case 0x40: return 0;
-    case 0x50: return 1;
-    case 0x60: return 2;
-    case 0x70: return 4;
-    case 0x80: return 8;
-    case 0x90: return 16;
-    case 0xB0:
-    case 0xD0:
-    case 0xF0:
-        length += ((unsigned int) dx_field_iterator_octet(iter)) << 24;
-        length += ((unsigned int) dx_field_iterator_octet(iter)) << 16;
-        length += ((unsigned int) dx_field_iterator_octet(iter)) << 8;
-        // fall through to the next case
-        
-    case 0xA0:
-    case 0xC0:
-    case 0xE0:
-        length += (unsigned int) dx_field_iterator_octet(iter);
-        break;
-
-    default:
-        return 0;
-    }
-
-    return length;
-}
-
-
-dx_field_iterator_t *dx_field_raw(dx_field_iterator_t *iter)
-{
-    dx_field_iterator_reset(iter);
-    unsigned char tag   = dx_field_iterator_octet(iter);
-    unsigned int length = dx_field_get_length(iter, tag);
-
-    dx_field_iterator_t *result = new_dx_field_iterator_t();
-    if (!result)
-        return 0;
-    result->start_pointer        = iter->pointer;
-    result->start_pointer.length = length;
-    result->view_start_pointer   = result->start_pointer;
-    result->pointer              = result->start_pointer;
-    result->view                 = ITER_VIEW_ALL;
-    result->mode                 = MODE_TO_END;
-    result->at_prefix            = 0;
-    result->view_prefix          = 0;
-    result->tag                  = 0;
-
-    return result;
-}
-
-
 dx_iovec_t *dx_field_iterator_iovec(const dx_field_iterator_t *iter)
 {
     assert(!iter->view_prefix); // Not supported for views with a prefix
diff --git a/qpid/extras/dispatch/src/message.c b/qpid/extras/dispatch/src/message.c
index 8576bd5146..6d75de76db 100644
--- a/qpid/extras/dispatch/src/message.c
+++ b/qpid/extras/dispatch/src/message.c
@@ -18,6 +18,7 @@
  */
 
 #include <qpid/dispatch/ctools.h>
+#include <qpid/dispatch/amqp.h>
 #include <qpid/dispatch/threading.h>
 #include "message_private.h"
 #include "compose_private.h"
diff --git a/qpid/extras/dispatch/src/parse.c b/qpid/extras/dispatch/src/parse.c
new file mode 100644
index 0000000000..5a9c26b7ca
--- /dev/null
+++ b/qpid/extras/dispatch/src/parse.c
@@ -0,0 +1,379 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * 
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#include <qpid/dispatch/alloc.h>
+#include <qpid/dispatch/ctools.h>
+#include <qpid/dispatch/parse.h>
+#include <qpid/dispatch/amqp.h>
+
+DEQ_DECLARE(dx_parsed_field_t, dx_parsed_field_list_t);
+
+struct dx_parsed_field_t {
+    DEQ_LINKS(dx_parsed_field_t);
+    dx_parsed_field_t      *parent;
+    dx_parsed_field_list_t  children;
+    uint8_t                 tag;
+    dx_field_iterator_t    *raw_iter;
+    const char             *parse_error;
+};
+
+ALLOC_DECLARE(dx_parsed_field_t);
+ALLOC_DEFINE(dx_parsed_field_t);
+
+
+static char *get_type_info(dx_field_iterator_t *iter, uint8_t *tag, uint32_t *length, uint32_t *count)
+{
+    if (dx_field_iterator_end(iter))
+        return "Insufficient Data to Determine Tag";
+    *tag    = dx_field_iterator_octet(iter);
+    *count  = 0;
+    *length = 0;
+
+    switch (*tag & 0xF0) {
+    case 0x40: *length = 0;  break;
+    case 0x50: *length = 1;  break;
+    case 0x60: *length = 2;  break;
+    case 0x70: *length = 4;  break;
+    case 0x80: *length = 8;  break;
+    case 0x90: *length = 16; break;
+    case 0xB0:
+    case 0xD0:
+    case 0xF0:
+        *length += ((unsigned int) dx_field_iterator_octet(iter)) << 24;
+        *length += ((unsigned int) dx_field_iterator_octet(iter)) << 16;
+        *length += ((unsigned int) dx_field_iterator_octet(iter)) << 8;
+        // fall through to the next case
+        
+    case 0xA0:
+    case 0xC0:
+    case 0xE0:
+        if (dx_field_iterator_end(iter))
+            return "Insufficient Data to Determine Length";
+        *length += (unsigned int) dx_field_iterator_octet(iter);
+        break;
+
+    default:
+        return "Invalid Tag - No Length Information";
+    }
+
+    switch (*tag & 0xF0) {
+    case 0xD0:
+    case 0xF0:
+        *count += ((unsigned int) dx_field_iterator_octet(iter)) << 24;
+        *count += ((unsigned int) dx_field_iterator_octet(iter)) << 16;
+        *count += ((unsigned int) dx_field_iterator_octet(iter)) << 8;
+        // fall through to the next case
+        
+    case 0xC0:
+    case 0xE0:
+        if (dx_field_iterator_end(iter))
+            return "Insufficient Data to Determine Count";
+        *count += (unsigned int) dx_field_iterator_octet(iter);
+        break;
+    }
+
+    if ((*tag == DX_AMQP_MAP8 || *tag == DX_AMQP_MAP32) && (*count & 1))
+        return "Odd Number of Elements in a Map";
+
+    return 0;
+}
+
+
+static dx_parsed_field_t *dx_parse_internal(dx_field_iterator_t *iter, dx_parsed_field_t *p)
+{
+    dx_parsed_field_t *field = new_dx_parsed_field_t();
+    if (!field)
+        return 0;
+
+    DEQ_ITEM_INIT(field);
+    DEQ_INIT(field->children);
+    field->parent   = p;
+    field->raw_iter = 0;
+
+    uint32_t length;
+    uint32_t count;
+
+    field->parse_error = get_type_info(iter, &field->tag, &length, &count);
+
+    if (!field->parse_error) {
+        field->raw_iter = dx_field_iterator_sub(iter, length);
+        if (count == 0 && length > 0)
+            dx_field_iterator_advance(iter, length);
+        for (uint32_t idx = 0; idx < count; idx++) {
+            dx_parsed_field_t *child = dx_parse_internal(field->raw_iter, field);
+            DEQ_INSERT_TAIL(field->children, child);
+            if (!dx_parse_ok(child)) {
+                field->parse_error = child->parse_error;
+                break;
+            }
+        }
+    }
+
+    return field;
+}
+
+
+dx_parsed_field_t *dx_parse(dx_field_iterator_t *iter)
+{
+    return dx_parse_internal(iter, 0);
+}
+
+
+void dx_parse_free(dx_parsed_field_t *field)
+{
+    if (!field)
+        return;
+
+    assert(field->parent == 0);
+    if (field->raw_iter)
+        dx_field_iterator_free(field->raw_iter);
+
+    dx_parsed_field_t *sub_field = DEQ_HEAD(field->children);
+    while (sub_field) {
+        dx_parsed_field_t *next = DEQ_NEXT(sub_field);
+        DEQ_REMOVE_HEAD(field->children);
+        sub_field->parent = 0;
+        dx_parse_free(sub_field);
+        sub_field = next;
+    }
+
+    free_dx_parsed_field_t(field);
+}
+
+
+int dx_parse_ok(dx_parsed_field_t *field)
+{
+    return field->parse_error == 0;
+}
+
+
+const char *dx_parse_error(dx_parsed_field_t *field)
+{
+    return field->parse_error;
+}
+
+
+uint8_t dx_parse_tag(dx_parsed_field_t *field)
+{
+    return field->tag;
+}
+
+
+dx_field_iterator_t *dx_parse_raw(dx_parsed_field_t *field)
+{
+    return field->raw_iter;
+}
+
+
+uint32_t dx_parse_as_uint(dx_parsed_field_t *field)
+{
+    uint32_t result = 0;
+
+    dx_field_iterator_reset(field->raw_iter);
+
+    switch (field->tag) {
+    case DX_AMQP_UINT:
+        result |= ((uint32_t) dx_field_iterator_octet(field->raw_iter)) << 24;
+
+    case DX_AMQP_USHORT:
+        result |= ((uint32_t) dx_field_iterator_octet(field->raw_iter)) << 16;
+        result |= ((uint32_t) dx_field_iterator_octet(field->raw_iter)) << 8;
+        // Fall Through...
+
+    case DX_AMQP_UBYTE:
+    case DX_AMQP_SMALLUINT:
+    case DX_AMQP_BOOLEAN:
+        result |= (uint32_t) dx_field_iterator_octet(field->raw_iter);
+        break;
+
+    case DX_AMQP_TRUE:
+        result = 1;
+        break;
+    }
+
+    return result;
+}
+
+
+uint64_t dx_parse_as_ulong(dx_parsed_field_t *field)
+{
+    uint64_t result = 0;
+
+    dx_field_iterator_reset(field->raw_iter);
+
+    switch (field->tag) {
+    case DX_AMQP_ULONG:
+        result |= ((uint64_t) dx_field_iterator_octet(field->raw_iter)) << 56;
+        result |= ((uint64_t) dx_field_iterator_octet(field->raw_iter)) << 48;
+        result |= ((uint64_t) dx_field_iterator_octet(field->raw_iter)) << 40;
+        result |= ((uint64_t) dx_field_iterator_octet(field->raw_iter)) << 32;
+        result |= ((uint64_t) dx_field_iterator_octet(field->raw_iter)) << 24;
+        result |= ((uint64_t) dx_field_iterator_octet(field->raw_iter)) << 16;
+        result |= ((uint64_t) dx_field_iterator_octet(field->raw_iter)) << 8;
+        // Fall Through...
+
+    case DX_AMQP_SMALLULONG:
+        result |= (uint64_t) dx_field_iterator_octet(field->raw_iter);
+        // Fall Through...
+
+    case DX_AMQP_ULONG0:
+        break;
+    }
+
+    return result;
+}
+
+
+int32_t dx_parse_as_int(dx_parsed_field_t *field)
+{
+    int32_t result = 0;
+
+    dx_field_iterator_reset(field->raw_iter);
+
+    switch (field->tag) {
+    case DX_AMQP_INT:
+        result |= ((int32_t) dx_field_iterator_octet(field->raw_iter)) << 24;
+
+    case DX_AMQP_SHORT:
+        result |= ((int32_t) dx_field_iterator_octet(field->raw_iter)) << 16;
+        result |= ((int32_t) dx_field_iterator_octet(field->raw_iter)) << 8;
+        // Fall Through...
+
+    case DX_AMQP_BYTE:
+    case DX_AMQP_SMALLINT:
+    case DX_AMQP_BOOLEAN:
+        result |= (int32_t) dx_field_iterator_octet(field->raw_iter);
+        break;
+
+    case DX_AMQP_TRUE:
+        result = 1;
+        break;
+    }
+
+    return result;
+}
+
+
+int64_t dx_parse_as_long(dx_parsed_field_t *field)
+{
+    int64_t result = 0;
+
+    dx_field_iterator_reset(field->raw_iter);
+
+    switch (field->tag) {
+    case DX_AMQP_LONG:
+        result |= ((int64_t) dx_field_iterator_octet(field->raw_iter)) << 56;
+        result |= ((int64_t) dx_field_iterator_octet(field->raw_iter)) << 48;
+        result |= ((int64_t) dx_field_iterator_octet(field->raw_iter)) << 40;
+        result |= ((int64_t) dx_field_iterator_octet(field->raw_iter)) << 32;
+        result |= ((int64_t) dx_field_iterator_octet(field->raw_iter)) << 24;
+        result |= ((int64_t) dx_field_iterator_octet(field->raw_iter)) << 16;
+        result |= ((int64_t) dx_field_iterator_octet(field->raw_iter)) << 8;
+        // Fall Through...
+
+    case DX_AMQP_SMALLLONG:
+        result |= (uint64_t) dx_field_iterator_octet(field->raw_iter);
+        break;
+    }
+
+    return result;
+}
+
+
+uint32_t dx_parse_sub_count(dx_parsed_field_t *field)
+{
+    uint32_t count = DEQ_SIZE(field->children);
+
+    if (field->tag == DX_AMQP_MAP8 || field->tag == DX_AMQP_MAP32)
+        count = count >> 1;
+
+    return count;
+}
+
+
+dx_parsed_field_t *dx_parse_sub_key(dx_parsed_field_t *field, uint32_t idx)
+{
+    if (field->tag != DX_AMQP_MAP8 && field->tag != DX_AMQP_MAP32)
+        return 0;
+
+    idx = idx << 1;
+    dx_parsed_field_t *key = DEQ_HEAD(field->children);
+    while (idx && key) {
+        idx--;
+        key = DEQ_NEXT(key);
+    }
+
+    return key;
+}
+
+
+dx_parsed_field_t *dx_parse_sub_value(dx_parsed_field_t *field, uint32_t idx)
+{
+    if (field->tag == DX_AMQP_MAP8 || field->tag == DX_AMQP_MAP32)
+        idx = (idx << 1) + 1;
+
+    dx_parsed_field_t *key = DEQ_HEAD(field->children);
+    while (idx && key) {
+        idx--;
+        key = DEQ_NEXT(key);
+    }
+
+    return key;
+}
+
+
+int dx_parse_is_map(dx_parsed_field_t *field)
+{
+    return field->tag == DX_AMQP_MAP8 || field->tag == DX_AMQP_MAP32;
+}
+
+
+int dx_parse_is_list(dx_parsed_field_t *field)
+{
+    return field->tag == DX_AMQP_LIST8 || field->tag == DX_AMQP_LIST32;
+}
+
+
+int dx_parse_is_scalar(dx_parsed_field_t *field)
+{
+    return DEQ_SIZE(field->children) == 0;
+}
+
+
+dx_parsed_field_t *dx_parse_value_by_key(dx_parsed_field_t *field, const char *key)
+{
+    uint32_t count = dx_parse_sub_count(field);
+
+    for (uint32_t idx = 0; idx < count; idx++) {
+        dx_parsed_field_t *sub  = dx_parse_sub_key(field, idx);
+        if (!sub)
+            return 0;
+
+        dx_field_iterator_t *iter = dx_parse_raw(sub);
+        if (!iter)
+            return 0;
+
+        if (dx_field_iterator_equal(iter, (const unsigned char*) key)) {
+            return dx_parse_sub_value(field, idx);
+        }
+    }
+
+    return 0;
+}
+