provide a tool which can inspect frames

bin/build_tool.sh

@@ -0,0 +1,2 @@
+#!/bin/bash
+g++ mbus-inspect-frame.cpp -I../ -lmbus -L../mbus/.libs/ -static -o mbus-inspect-frame

bin/mbus-inspect-frame.cpp

@@ -0,0 +1,84 @@
+#include <string>
+#include <iostream>
+#include <sstream>
+#include <cstdio>
+
+extern "C" {
+#include <mbus/mbus.h>
+}
+
+int read_hex_formated_frame(unsigned char* data, int maxsize) {
+    std::string line;
+    if(!std::getline(std::cin, line)) {
+        return -1;
+    }
+
+    std::istringstream hex_chars(line);
+
+    // read from stdin and count bytes
+    int out = 0;
+    unsigned int c;
+    while( hex_chars >> std::hex >> c ){
+        out++;
+        if ( out >= maxsize) {
+            return -1;
+        }
+        data[out - 1] = c;
+    }
+
+    data[out] = '\0';
+    return out;
+}
+
+
+// just format framedata
+// for debug usage
+int
+main(int argc, char **argv)
+{
+    unsigned char data[500];
+    mbus_frame reply;
+    mbus_frame_data reply_data;
+    char* xml_result;
+
+    int line_length = read_hex_formated_frame(data, 500);
+    if (line_length  <= 0)
+    {
+        std::cout << "line couldnt be parsed in any way, or was too long (500 bytes)" << std::endl;
+        return 0;
+    }
+
+    if (mbus_parse(&reply, data, line_length) < 0)
+    {
+        fprintf(stderr, "M-bus parse_data error: %s %d\n", mbus_error_str(), line_length);
+        return 1;
+    }
+    //
+    // parse data
+    //
+    if (mbus_frame_data_parse(&reply, &reply_data) == -1)
+    {
+        fprintf(stderr, "M-bus data parse error: %s\n", mbus_error_str());
+        return 1;
+    }
+
+    //
+    // generate XML and print to standard output
+    //
+    if ((xml_result = mbus_frame_data_xml(&reply_data)) == NULL)
+    {
+        fprintf(stderr, "Failed to generate XML representation of MBUS frame: %s\n", mbus_error_str());
+        return 1;
+    }
+
+    printf("%s", xml_result);
+    free(xml_result);
+
+    // manual free
+    if (reply_data.data_var.record)
+    {
+        mbus_data_record_free(reply_data.data_var.record); // free's up the whole list
+    }
+
+    return 0;
+}

mbus/mbus-protocol.c

@@ -4649,9 +4649,11 @@ mbus_data_variable_record_xml(mbus_data_record *record, int record_cnt, int fram
         if (record->timestamp > 0)
         {
             timeinfo = gmtime (&(record->timestamp));
-            strftime(timestamp,21,"%Y-%m-%dT%H:%M:%SZ",timeinfo);
-            len += snprintf(&buff[len], sizeof(buff) - len,
+            if(timeinfo) {
+                strftime(timestamp,21,"%Y-%m-%dT%H:%M:%SZ",timeinfo);
+                len += snprintf(&buff[len], sizeof(buff) - len,
                             "        <Timestamp>%s</Timestamp>\n", timestamp);
+            }
         }
 
         len += snprintf(&buff[len], sizeof(buff) - len, "    </DataRecord>\n\n");