Implement index_ranges2 for C++

code/c++/index_ranges2.cc

@@ -0,0 +1,103 @@
+#include <xapian.h>
+
+#include <cstdlib>
+#include <fstream>
+#include <iostream>
+#include <string>
+#include <vector>
+
+#include "support.h"
+
+using namespace std;
+
+void index(const string & datapath, const string & dbpath)
+{
+    // Hardcode field offsets for simplicity.
+    const size_t FIELD_NAME = 0;
+    const size_t FIELD_ADMITTED = 2;
+    const size_t FIELD_ORDER = 3;
+    const size_t FIELD_POPULATION = 4;
+    const size_t FIELD_MOTTO = 7;
+    const size_t FIELD_DESCRIPTION = 8;
+
+    // Create or open the database we're going to be writing to.
+    Xapian::WritableDatabase db(dbpath, Xapian::DB_CREATE_OR_OPEN);
+
+    // Set up a TermGenerator that we'll use in indexing.
+    Xapian::TermGenerator termgenerator;
+    termgenerator.set_stemmer(Xapian::Stem("en"));
+
+    ifstream csv(datapath.c_str());
+    vector<string> fields;
+    csv_parse_line(csv, fields);
+
+    // Check the CSV header line matches our hard-code offsets.
+    if (fields.at(FIELD_NAME) != "name" ||
+	fields.at(FIELD_ADMITTED) != "admitted" ||
+	fields.at(FIELD_ORDER) != "order" ||
+	fields.at(FIELD_POPULATION) != "population" ||
+	fields.at(FIELD_MOTTO) != "motto" ||
+	fields.at(FIELD_DESCRIPTION) != "description") {
+	// The CSV format doesn't match what we expect.
+	cerr << "CSV format has changed!" << endl;
+	exit(1);
+    }
+
+    while (csv_parse_line(csv, fields)) {
+	// 'fields' is a vector mapping from field number to value.
+	// We look up fields with the 'at' method so we get an exception
+	// if that field isn't set.
+	const string & name = fields.at(FIELD_NAME);
+	const string & description = fields.at(FIELD_DESCRIPTION);
+	const string & motto = fields.at(FIELD_MOTTO);
+	const string & admitted = fields.at(FIELD_ADMITTED);
+	const string & population = fields.at(FIELD_POPULATION);
+	const string & order = fields.at(FIELD_ORDER);
+
+	// We make a document and tell the term generator to use this.
+	Xapian::Document doc;
+	termgenerator.set_document(doc);
+
+// Start of example code.
+	// Index each field with a suitable prefix.
+	termgenerator.index_text(name, 1, "S");
+	termgenerator.index_text(description, 1, "XD");
+	termgenerator.index_text(motto, 1, "XM");
+
+	// Index fields without prefixes for general search.
+	termgenerator.index_text(name);
+	termgenerator.increase_termpos();
+	termgenerator.index_text(description);
+	termgenerator.increase_termpos();
+	termgenerator.index_text(motto);
+
+	// Add document values.
+	if (!admitted.empty()) {
+	    doc.add_value(1, xapian.sortable_serialise(atoi(admitted.substr(0, 4).c_str())));
+	    doc.add_value(2, admitted); // YYYYMMDD
+	}
+	if (!population.empty()) {
+	    doc.add_value(3, xapian.sortable_serialise(atoi(population.c_str())));
+	}
+// End of example code.
+
+	// Store all the fields for display purposes.
+	doc.set_data(name + "\n" + description + "\n" + motto + "\n" +
+		     admitted + "\n" + population + "\n" + order);
+
+	// We use the order to ensure each object ends up in the
+	// database only once no matter how many times we run the
+	// indexer.
+	string idterm = "Q" + order;
+	doc.add_boolean_term(idterm);
+	db.replace_document(idterm, doc);
+    }
+}
+
+int main(int argc, char** argv) {
+    if (argc != 3) {
+	cerr << "Usage: " << argv[0] << " DATAPATH DBPATH" << endl;
+	return 1;
+    }
+    index(argv[1], argv[2]);
+}