This will update the amalgamate_demo.cpp file to use On Demand. (#1689)

* This will update the amalgamate_demo.cpp file to use On Demand.

* Making the demo exceptionless.

singleheader/amalgamate_demo.cpp

@@ -1,35 +1,70 @@
-#include <iostream>
-#include "simdjson.h"
 #include "simdjson.cpp"
+#include "simdjson.h"
+#include <iostream>
 
 int main(int argc, char *argv[]) {
-  if(argc < 2) {
-    std::cerr << "Please specify at least one file name. " << std::endl;
+  if (argc < 2) {
+    std::cerr << "Please specify at least one file name and" << std::endl;
+    std::cerr << "up to two files." << std::endl;
+    std::cerr << "The first file should be a JSON document." << std::endl;
+    std::cerr << "The secod file should container many JSON documents."
+              << std::endl;
+    std::cerr << "Try the test files: jsonexamples/twitter.json "
+                 "jsonexamples/amazon_cellphones.ndjson"
+              << std::endl;
     return EXIT_FAILURE;
   }
-  const char * filename = argv[1];
-  simdjson::dom::parser parser;
-  simdjson::dom::element elem;
-  auto error = parser.load(filename).get(elem); // do the parsing
+  const char *filename = argv[1];
+
+  simdjson::padded_string json;
+  std::cout << "loading: " << filename << std::endl;
+  auto error = simdjson::padded_string::load(filename).get(json);
   if (error) {
-    std::cout << "parse failed" << std::endl;
+    std::cout << "could not load the file " << filename << std::endl;
     std::cout << "error code: " << error << std::endl;
-    std::cout << error << std::endl;
     return EXIT_FAILURE;
   } else {
-    std::cout << "parse valid: " << elem << std::endl;
+    std::cout << "loaded: " << json.size() << " bytes." << std::endl;
   }
-  if(argc == 2) {
+  simdjson::ondemand::parser parser;
+  simdjson::ondemand::document doc;
+  error = parser.iterate(json).get(doc);
+  if (error) {
+    std::cout << error << std::endl;
+    return EXIT_FAILURE;
+  }
+  simdjson::ondemand::json_type type;
+  error = doc.type().get(type);
+  if (error) {
+    std::cout << error << std::endl;
+    return EXIT_FAILURE;
+  }
+  std::cout << "document has the following type at the root: " << type
+            << std::endl;
+
+  if (argc == 2) {
     return EXIT_SUCCESS;
   }
 
-  // parse_many
-  const char * filename2 = argv[2];
-  simdjson::dom::document_stream stream;
-  error = parser.load_many(filename2).get(stream);
+  // iterate_many
+  const char *filename2 = argv[2];
+  std::cout << "loading: " << filename2 << std::endl;
+  simdjson::padded_string json2;
+  error = simdjson::padded_string::load(filename2).get(json2);
+  if (error) {
+    std::cout << "could not load the file " << filename2 << std::endl;
+    std::cout << "error code: " << error << std::endl;
+    return EXIT_FAILURE;
+  } else {
+    std::cout << "loaded: " << json2.size() << " bytes." << std::endl;
+  }
+  simdjson::ondemand::document_stream stream;
+  error = parser.iterate_many(json2).get(stream);
+  size_t counter{0};
   if (!error) {
     for (auto result : stream) {
       error = result.error();
+      counter++;
     }
   }
   if (error) {
@@ -38,8 +73,8 @@ int main(int argc, char *argv[]) {
     std::cout << error << std::endl;
     return EXIT_FAILURE;
   } else {
-    std::cout << "parse_many valid" << std::endl;
+    std::cout << "iterate_many valid" << std::endl;
+    std::cout << "found " << counter << " documents" << std::endl;
   }
   return EXIT_SUCCESS;
 }
-