From 8709fb6f7ccf2cf4598fc2bab635e757340f39c2 Mon Sep 17 00:00:00 2001
From: artemp <artem@mapnik.org>
Date: Mon, 24 Aug 2015 16:35:32 +0200
Subject: [PATCH] CSV - optimise parsing by providing num_columns hint

---
 include/mapnik/csv/csv_grammar.hpp   | 13 +++++++------
 plugins/input/csv/csv_featureset.cpp |  2 +-
 plugins/input/csv/csv_featureset.hpp |  2 +-
 plugins/input/csv/csv_utils.hpp      |  7 ++++---
 4 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/include/mapnik/csv/csv_grammar.hpp b/include/mapnik/csv/csv_grammar.hpp
index 62bfc4166..d6996a96e 100644
--- a/include/mapnik/csv/csv_grammar.hpp
+++ b/include/mapnik/csv/csv_grammar.hpp
@@ -37,13 +37,14 @@ using csv_line = columns;
 using csv_data = std::vector<csv_line>;
 
 template <typename Iterator>
-struct csv_line_grammar : qi::grammar<Iterator, csv_line(std::string const&), qi::blank_type>
+struct csv_line_grammar : qi::grammar<Iterator, void(csv_line&, std::string const&), qi::blank_type>
 {
     csv_line_grammar() : csv_line_grammar::base_type(line)
     {
         using namespace qi;
         qi::_a_type _a;
         qi::_r1_type _r1;
+        qi::_r2_type _r2;
         qi::lit_type lit;
         //qi::eol_type eol;
         qi::_val_type _val;
@@ -65,18 +66,18 @@ struct csv_line_grammar : qi::grammar<Iterator, csv_line(std::string const&), qi
             ("\"\"", '\"') // double quote
             ;
 
-        line = column(_r1) % char_(_r1)
+        line = column(_r2)[boost::phoenix::push_back(_r1,_1)]  % char_(_r2)
             ;
         column = quoted | *(char_ - (lit(_r1) /*| eol*/))
             ;
-        text = *(unesc_char |  (char_ - char_(_r1)))
+        quoted = omit[char_("\"'")[_a = _1]] > text(_a)[boost::phoenix::swap(_val,_1)] > -lit(_a)
             ;
-        quoted = omit[char_("\"'")[_a = _1]] >> text(_a)[_val = _1] >> -lit(_a)
+        text = *(unesc_char | (char_ - char_(_r1)))
             ;
-        BOOST_SPIRIT_DEBUG_NODES((line)(column)(quoted));
+        //BOOST_SPIRIT_DEBUG_NODES((line)(column)(quoted));
     }
   private:
-    qi::rule<Iterator, csv_line(std::string const&), qi::blank_type> line;
+    qi::rule<Iterator, void(csv_line&,std::string const&), qi::blank_type> line;
     qi::rule<Iterator, column(std::string const&)> column; // no-skip
     qi::rule<Iterator, std::string(char)> text;
     qi::rule<Iterator, qi::locals<char>, std::string()> quoted;
diff --git a/plugins/input/csv/csv_featureset.cpp b/plugins/input/csv/csv_featureset.cpp
index 9219dec03..4a9e74a9f 100644
--- a/plugins/input/csv/csv_featureset.cpp
+++ b/plugins/input/csv/csv_featureset.cpp
@@ -55,7 +55,7 @@ csv_featureset::~csv_featureset() {}
 
 mapnik::feature_ptr csv_featureset::parse_feature(char const* beg, char const* end)
 {
-    auto values = csv_utils::parse_line(beg, end, separator_);
+    auto values = csv_utils::parse_line(beg, end, separator_, headers_.size());
     auto geom = detail::extract_geometry(values, locator_);
     if (!geom.is<mapnik::geometry::geometry_empty>())
     {
diff --git a/plugins/input/csv/csv_featureset.hpp b/plugins/input/csv/csv_featureset.hpp
index 380a582bf..1fc2103f2 100644
--- a/plugins/input/csv/csv_featureset.hpp
+++ b/plugins/input/csv/csv_featureset.hpp
@@ -48,7 +48,7 @@ private:
     mapnik::feature_ptr parse_feature(char const* beg, char const* end);
     file_ptr file_;
     std::string const& separator_;
-    std::vector<std::string> headers_;
+    std::vector<std::string> const& headers_;
     const array_type index_array_;
     array_type::const_iterator index_itr_;
     array_type::const_iterator index_end_;
diff --git a/plugins/input/csv/csv_utils.hpp b/plugins/input/csv/csv_utils.hpp
index 79653e273..67bb47864 100644
--- a/plugins/input/csv/csv_utils.hpp
+++ b/plugins/input/csv/csv_utils.hpp
@@ -49,11 +49,12 @@ namespace csv_utils
 
 static const mapnik::csv_line_grammar<char const*> line_g;
 
-static mapnik::csv_line parse_line(char const* start, char const* end, std::string const& separator)
+static mapnik::csv_line parse_line(char const* start, char const* end, std::string const& separator, std::size_t num_columns)
 {
     mapnik::csv_line values;
+    if (num_columns > 0) values.reserve(num_columns);
     boost::spirit::standard::blank_type blank;
-    if (!boost::spirit::qi::phrase_parse(start, end, (line_g)(boost::phoenix::cref(separator)), blank,values))
+    if (!boost::spirit::qi::phrase_parse(start, end, (line_g)(boost::phoenix::ref(values), boost::phoenix::cref(separator)), blank))
     {
         throw std::runtime_error("Failed to parse CSV line:\n" + std::string(start, end));
     }
@@ -64,7 +65,7 @@ static mapnik::csv_line parse_line(std::string const& line_str, std::string cons
 {
     auto start = line_str.c_str();
     auto end   = start + line_str.length();
-    return parse_line(start, end, separator);
+    return parse_line(start, end, separator, 0);
 }
 
 static inline bool is_likely_number(std::string const& value)