Implemented ReadRange functionality for the device "Device Address Binding" property and modified the ReadRange test app to use this real property for its target.

Implemented a framework for allowing the ReadRange handler determine which properties support ReadRange and which varients of ReadRange they support.

bacnet-stack/include/readrange.h

@@ -31,6 +31,11 @@
  License.
  -------------------------------------------
 ####COPYRIGHTEND####*/
+#ifndef READRANGE_H
+#define READRANGE_H
+
+#include "bacstr.h"
+#include "datetime.h"
 
 struct BACnet_Read_Range_Data;
 typedef struct BACnet_Read_Range_Data {
@@ -42,6 +47,7 @@ typedef struct BACnet_Read_Range_Data {
     int application_data_len;
     BACNET_BIT_STRING ResultFlags;      /*  FIRST_ITEM, LAST_ITEM, MORE_ITEMS */
     int RequestType;    /* Index, sequence or time based request */
+    int Overhead;        /* How much space the baggage takes in the response */
     uint32_t ItemCount;
     uint32_t FirstSequence;
     union {     /* Pick the appropriate data type */
@@ -52,12 +58,15 @@ typedef struct BACnet_Read_Range_Data {
     int32_t Count;      /* SIGNED value as +ve vs -ve  is important */
 } BACNET_READ_RANGE_DATA;
 
-/* Defines to indicate which type of read range request it is */
+/* Defines to indicate which type of read range request it is
+   Not really a bit map but we do it like this to allow quick
+   checking of request against capabilities for the property */
 
-#define RR_BY_POSITION 0
-#define RR_BY_SEQUENCE 1
-#define RR_BY_TIME     2
-#define RR_READ_ALL    4        /* Read all of array - so don't send any range in the request */
+#define RR_BY_POSITION    1
+#define RR_BY_SEQUENCE    2
+#define RR_BY_TIME        4
+#define RR_READ_ALL       8    /* Read all of array - so don't send any range in the request */
+#define RR_ARRAY_OF_LISTS 16   /* For info functionality indicates array of lists if set */
 
 /* Bit String Enumerations */
 typedef enum {
@@ -66,6 +75,67 @@ typedef enum {
     RESULT_FLAG_MORE_ITEMS = 2
 } BACNET_RESULT_FLAGS;
 
+/* Defines for ReadRange packet overheads to allow us to determine how
+ * much space is left for actual payload:
+ *
+ * Overhead is comprised of: 
+ * 1. PDU Type + invoke ID + service type = 3 bytes
+ * 2. Object ID = 5 bytes
+ * 3. Object Property = 2 bytes if property is 0-255, 3 if property is
+ *    256-65535 – theoretical max of 5 bytes but how likely is that?
+ * 4. Optional array index = 2 bytes if index is 0-255, 3 if index is 
+ *    256-65535 – theoretical max of 5 bytes but how likely is that?
+ * 5. Flags = 3 bytes
+ * 6. Opening and closing tag for data = 2 bytes
+ * 7. firstSequenceNumber [6] Unsigned32 OPTIONAL -- used only if 'Item Count' > 0
+ *    and the request was either of  type 'By Sequence Number' or 'By Time'
+ *    = minimum of 2 bytes, maximum of 5 bytes.
+ *
+ * These figures give an absolute worst-case overhead of 28 bytes. A less
+ * conservative value (if we assume object property is 3 bytes and array
+ * index is 3 bytes) is 24. */
+
+/* This is the fixed part of the overhead before we check for array and
+ * first sequence number requirements. again if you are really paranoid
+ * use a value of 18 */
+
+#define RR_OVERHEAD         16
+#define RR_1ST_SEQ_OVERHEAD 5
+#define RR_INDEX_OVERHEAD   3 /* or 5 if paranoid */ 
+ 
+/* Define pointer to function type for handling ReadRange request.
+   This function will take the following parameters:
+   1. A pointer to a buffer of at least MAX_APDU bytes to build the response in.
+   2. A pointer to a BACNET_READ_RANGE_DATA structure with all the request
+      information in it. The function is responsible for applying the request
+      to the property in question and returning the response.
+   3/4. pointers to Error Class and Error Code values to write to in the
+      event of a failure. */
+   
+typedef int (*rr_handler_function) (
+    uint8_t *apdu,
+    BACNET_READ_RANGE_DATA *pRequest,
+    BACNET_ERROR_CLASS *error_class,
+    BACNET_ERROR_CODE  *error_code);
+
+/* Structure to return the type of requests a given object property can
+ * accept and the address of the function to handle the request */
+ 
+typedef struct rrpropertyinfo {
+    int RequestTypes;
+    rr_handler_function Handler;
+    } RR_PROP_INFO;
+
+/* Function pointer for ReadRange information retrieval function */
+
+typedef bool (*rr_info_function) (
+    uint32_t           Object,   /* Which particular object instance (we know the type implicetly) */
+    BACNET_PROPERTY_ID Property, /* Which property */
+    RR_PROP_INFO *pInfo,         /* Where to write the response to */
+    BACNET_ERROR_CLASS *error_class, /* Somewhere to write error responses to */
+    BACNET_ERROR_CODE  *error_code);
+
+
 int rr_encode_apdu(
     uint8_t * apdu,
     uint8_t invoke_id,
@@ -89,3 +159,6 @@ int rr_ack_decode_service_request(
 uint8_t Send_ReadRange_Request(
     uint32_t device_id, /* destination device */
     BACNET_READ_RANGE_DATA * read_access_data);
+    
+#endif
+