faster double and date parsing

ml_date.cpp

@@ -23,19 +23,59 @@ std::string date_to_string(const long datetime, const std::string format) {
 	return "invalid argument";
 }
 
+time_t time_to_epoch ( const struct tm *ltm, int utcdiff ) {
+	//   const int mon_days [] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
+	const int mon_days [] = {31, 31+28, 31+28+31,
+				 31+28+31+30, 31+28+31+30+31, 31+28+31+30+31+30,
+				 31+28+31+30+31+30+31, 31+28+31+30+31+30+31+31, 31+28+31+30+31+30+31+31+30,
+				 31+28+31+30+31+30+31+31+30+31, 31+28+31+30+31+30+31+31+30+31+30, 31+28+31+30+31+30+31+31+30+31+30+31};
+
+	long tyears, tdays, leaps, utc_hrs;
+	int i;
+
+	tyears = ltm->tm_year - 70 ; // tm->tm_year is from 1900.
+	leaps = (tyears + 2) / 4; // no of next two lines until year 2100.
+	//i = (ltm->tm_year – 100) / 100;
+	//leaps -= ( (i/4)*3 + i%4 );
+
+	//   tdays = 0;
+	//   for (i=0; i < ltm->tm_mon; i++) tdays += mon_days[i];
+	tdays = mon_days[ltm->tm_mon-1];
+
+	tdays += ltm->tm_mday-1; // days of month passed.
+	tdays = tdays + (tyears * 365) + leaps;
+
+	utc_hrs = ltm->tm_hour + utcdiff/3600; // for your time zone.
+	return (tdays * 86400) + (utc_hrs * 3600) + (ltm->tm_min * 60) + ltm->tm_sec;
+}
 
-std::istringstream in_ss;
 long string_to_date(const std::string &datestr, const std::string &format) {
 	// format for example "%d.%m.%Y";
 
-	in_ss.clear();
-	in_ss.str(datestr);
+	struct tm tm;
+	memset(&tm, 0, sizeof(tm));
+	if (strptime(datestr.c_str(), format.c_str(), &tm)) {
+		time_t curTime;
+		struct tm * timeinfo;
 
-	date::sys_seconds tp;
-	date::from_stream(in_ss, format.c_str(), tp);
-	return tp.time_since_epoch().count();
+		time(&curTime );
+		timeinfo = localtime(&curTime);
+
+		timeinfo->tm_year = tm.tm_year;
+		timeinfo->tm_mon = tm.tm_mon;
+		timeinfo->tm_mday = tm.tm_mday;
+		timeinfo->tm_hour = tm.tm_hour;
+		timeinfo->tm_min = tm.tm_min;
+		timeinfo->tm_sec = tm.tm_sec;
+
+		return time_to_epoch(timeinfo, -1 * timeinfo->tm_gmtoff);
+	}
+
+	// throw Exception("invalid date string or format");
+	return -1;
 }
 
+
 long add_to_date(const long datetime, const long quantity, const std::string &part) {
 	// part is one of 'year', 'month', 'day', 'hour', 'minute' or 'second'
 

row.h

@@ -35,6 +35,8 @@ namespace usql {
 	bool getBoolValue() override { throw Exception("getDateValue not supported on ColNullValue"); };
 
 	int compare(ColValue &other) override;
+
+	virtual ~ColNullValue() = default;
     };
 
 
@@ -52,6 +54,8 @@ namespace usql {
 	int compare(ColValue &other) override;
 
 	long m_integer;
+
+	virtual ~ColIntegerValue() = default;
     };
 
 
@@ -68,6 +72,8 @@ namespace usql {
 
 	int compare(ColValue &other) override;
 
+	virtual ~ColDoubleValue() = default;
+
 	double m_double;
     };
 
@@ -103,6 +109,8 @@ namespace usql {
 
         int compare(ColValue &other) override;
 
+	virtual ~ColDateValue() = default;
+
         long m_date;	// seconds since epoch for now
     };
 
@@ -119,6 +127,8 @@ namespace usql {
 
         int compare(ColValue &other) override;
 
+	virtual ~ColBooleanValue() = default;
+
         bool m_bool;
     };
 

table.cpp

@@ -1,7 +1,9 @@
 #include "table.h"
 #include "csvreader.h"
 #include "ml_string.h"
+#include "fast_double_parser.h"
 
+#include <charconv>
 #include <fstream>
 #include <algorithm>
 
@@ -138,11 +140,12 @@ void Table::create_row_from_vector(const std::vector<ColDefNode> &colDefs, const
 }
 
 double Table::string_to_double(const std::string &s) {
-	try {
-		return std::stod(s);
-	} catch (std::invalid_argument &e) {
+	double result;
+	const char * endptr = fast_double_parser::parse_number(s.c_str(), &result);
+	if (endptr == nullptr) {
 		throw Exception("error parsing as double: " + s);
 	}
+	return result;
 }
 
 long Table::string_to_long(const std::string &s) {