Replace boost with C++20

CHANGELOG.rst

@@ -3,6 +3,11 @@ Version history / changelog
 
 From version 2.0.0, turbodbc adapts semantic versioning.
 
+Version 5.2.0
+--------------------
+
+* Drop ``boost``, use C++20
+
 Version 5.1.1, 5.1.2
 --------------------
 

cpp/turbodbc/Library/src/cursor.cpp

@@ -6,7 +6,7 @@
 #include <cpp_odbc/statement.h>
 #include <cpp_odbc/error.h>
 
-#include <boost/variant/get.hpp>
+#include <variant>
 #include <sqlext.h>
 #include <stdexcept>
 

cpp/turbodbc/Library/src/descriptions/boolean_description.cpp

@@ -1,6 +1,6 @@
 #include <turbodbc/descriptions/boolean_description.h>
 
-#include <boost/variant/get.hpp>
+#include <variant>
 #include <sqlext.h>
 
 namespace turbodbc {

cpp/turbodbc/Library/src/descriptions/date_description.cpp

@@ -2,7 +2,7 @@
 
 #include <sqlext.h>
 
-#include <boost/variant/get.hpp>
+#include <variant>
 #include <cstring>
 
 namespace turbodbc {

cpp/turbodbc/Library/src/descriptions/floating_point_description.cpp

@@ -2,7 +2,7 @@
 
 #include <sqlext.h>
 
-#include <boost/variant/get.hpp>
+#include <variant>
 #include <cstring>
 
 namespace turbodbc {

cpp/turbodbc/Library/src/descriptions/integer_description.cpp

@@ -2,7 +2,7 @@
 
 #include <sqlext.h>
 
-#include <boost/variant/get.hpp>
+#include <variant>
 #include <cstring>
 
 namespace turbodbc {

cpp/turbodbc/Library/src/descriptions/string_description.cpp

@@ -1,6 +1,6 @@
 #include <turbodbc/descriptions/string_description.h>
 
-#include <boost/variant/get.hpp>
+#include <variant>
 
 #include <sqlext.h>
 #include <cstring>

cpp/turbodbc/Library/src/descriptions/timestamp_description.cpp

@@ -2,7 +2,7 @@
 
 #include <sqlext.h>
 
-#include <boost/variant/get.hpp>
+#include <variant>
 #include <cstring>
 
 namespace turbodbc {

cpp/turbodbc/Library/src/descriptions/unicode_description.cpp

@@ -1,6 +1,6 @@
 #include <turbodbc/descriptions/unicode_description.h>
 
-#include <boost/variant/get.hpp>
+#include <variant>
 
 #ifdef _WIN32
 #include <windows.h>

cpp/turbodbc/Library/src/field_translators/boolean_translator.cpp

@@ -1,6 +1,6 @@
 #include <turbodbc/field_translators/boolean_translator.h>
 
-#include <boost/variant/get.hpp>
+#include <variant>
 
 
 namespace turbodbc { namespace field_translators {

cpp/turbodbc/Library/src/field_translators/date_translator.cpp

@@ -1,6 +1,6 @@
 #include <turbodbc/field_translators/date_translator.h>
 
-#include <boost/variant/get.hpp>
+#include <chrono>
 
 #include <sql.h>
 
@@ -13,8 +13,13 @@ date_translator::~date_translator() = default;
 
 field date_translator::do_make_field(char const * data_pointer) const
 {
-	auto const date = reinterpret_cast<SQL_DATE_STRUCT const *>(data_pointer);
-	return {boost::gregorian::date(date->year, date->month, date->day)};
+    auto const sql_date = reinterpret_cast<SQL_DATE_STRUCT const *>(data_pointer);
+    std::chrono::year_month_day ymd{
+        std::chrono::year{sql_date->year},
+        std::chrono::month{sql_date->month},
+        std::chrono::day{sql_date->day}
+    };
+    return {ymd};
 }
 
 

cpp/turbodbc/Library/src/field_translators/float64_translator.cpp

@@ -1,6 +1,6 @@
 #include <turbodbc/field_translators/float64_translator.h>
 
-#include <boost/variant/get.hpp>
+#include <variant>
 #include <sqlext.h>
 
 namespace turbodbc { namespace field_translators {

cpp/turbodbc/Library/src/field_translators/int64_translator.cpp

@@ -1,6 +1,6 @@
 #include <turbodbc/field_translators/int64_translator.h>
 
-#include <boost/variant/get.hpp>
+#include <variant>
 #include <sqlext.h>
 
 namespace turbodbc { namespace field_translators {

cpp/turbodbc/Library/src/field_translators/string_translator.cpp

@@ -1,6 +1,6 @@
 #include <turbodbc/field_translators/string_translator.h>
 
-#include <boost/variant/get.hpp>
+#include <variant>
 
 #include <stdexcept>
 

cpp/turbodbc/Library/src/field_translators/timestamp_translator.cpp

@@ -1,6 +1,6 @@
 #include <turbodbc/field_translators/timestamp_translator.h>
 
-#include <boost/variant/get.hpp>
+#include <chrono>
 
 #include <sql.h>
 
@@ -13,14 +13,24 @@ timestamp_translator::~timestamp_translator() = default;
 
 field timestamp_translator::do_make_field(char const * data_pointer) const
 {
-	auto const ts = reinterpret_cast<SQL_TIMESTAMP_STRUCT const *>(data_pointer);
-	// map SQL nanosecond precision to posix_time microsecond precision
-	int64_t const adjusted_fraction = ts->fraction / 1000;
-	return {boost::posix_time::ptime{
-										{static_cast<short unsigned int>(ts->year), ts->month, ts->day},
-										{ts->hour, ts->minute, ts->second, adjusted_fraction}
-									}
-			};
+    auto const ts = reinterpret_cast<SQL_TIMESTAMP_STRUCT const *>(data_pointer);
+    int64_t const adjusted_fraction = ts->fraction / 1000;
+
+    std::chrono::year_month_day ymd{
+        std::chrono::year{ts->year},
+        std::chrono::month{ts->month},
+        std::chrono::day{ts->day}
+    };
+    std::chrono::sys_days sd{ymd};
+
+    auto time_of_day = std::chrono::hours(ts->hour)
+                     + std::chrono::minutes(ts->minute)
+                     + std::chrono::seconds(ts->second)
+                     + std::chrono::microseconds(adjusted_fraction);
+
+    std::chrono::system_clock::time_point tp = sd + time_of_day;
+
+    return {tp};
 }
 
 } }

cpp/turbodbc/Library/src/make_description.cpp

@@ -3,12 +3,14 @@
 #include <turbodbc/descriptions.h>
 #include <sqlext.h>
 
-#include <boost/variant/apply_visitor.hpp>
+#include <chrono>
+#include <variant>
 
 #include <stdexcept>
 #include <sstream>
 #include <algorithm>
 
+#include <cmath> // for std::ceil
 
 namespace turbodbc {
 
@@ -64,7 +66,7 @@ std::unique_ptr<description const> make_decimal_description(cpp_odbc::column_des
 
 using description_ptr = description const *;
 
-struct description_by_value : public boost::static_visitor<description_ptr> {
+struct description_by_value {
     description_ptr operator()(int64_t const &) const
     {
         return new integer_description;
@@ -80,12 +82,12 @@ struct description_by_value : public boost::static_visitor<description_ptr> {
         return new boolean_description;
     }
 
-    description_ptr operator()(boost::gregorian::date const &) const
+    description_ptr operator()(std::chrono::year_month_day const &) const
     {
         return new date_description;
     }
 
-    description_ptr operator()(boost::posix_time::ptime const &) const
+    description_ptr operator()(std::chrono::system_clock::time_point const &) const
     {
         return new timestamp_description;
     }
@@ -164,7 +166,7 @@ std::unique_ptr<description const> make_description(cpp_odbc::column_description
 
 std::unique_ptr<description const> make_description(field const & value)
 {
-    return std::unique_ptr<description const>(boost::apply_visitor(description_by_value{}, value));
+    return std::unique_ptr<description const>(std::visit(description_by_value{}, value));
 }
 
 std::unique_ptr<description const> make_description(type_code type, std::size_t size)

cpp/turbodbc/Library/src/parameter_sets/set_field.cpp

@@ -1,16 +1,17 @@
 #include <turbodbc/parameter_sets/set_field.h>
 
-#include <boost/variant/static_visitor.hpp>
-#include <boost/variant/apply_visitor.hpp>
-
+#include <variant>
+#include <cstring>
+#include <chrono>
+#include <sql.h>
 
 namespace turbodbc {
 
 namespace {
 
 	std::size_t const size_not_important = 0;
 
-	class is_suitable_for : public boost::static_visitor<bool> {
+	class is_suitable_for {
 	public:
 		is_suitable_for(parameter const & param) :
 				parameter_(param)
@@ -28,11 +29,11 @@ namespace {
 			return parameter_.is_suitable_for(type_code::floating_point, size_not_important);
 		}
 
-		bool operator()(boost::posix_time::ptime const &) const {
+		bool operator()(std::chrono::system_clock::time_point const &) const {
 			return parameter_.is_suitable_for(type_code::timestamp, size_not_important);
 		}
 
-		bool operator()(boost::gregorian::date const &) const {
+		bool operator()(std::chrono::year_month_day const &) const {
 			return parameter_.is_suitable_for(type_code::date, size_not_important);
 		}
 
@@ -45,7 +46,7 @@ namespace {
 	};
 
 
-	class set_field_for : public boost::static_visitor<> {
+	class set_field_for {
 	public:
 		set_field_for(cpp_odbc::writable_buffer_element & destination) :
 				destination_(destination)
@@ -65,36 +66,41 @@ namespace {
 
 		void operator()(double const & value)
 		{
-			*reinterpret_cast<double *>(destination_.data_pointer) = boost::get<double>(value);
+			*reinterpret_cast<double *>(destination_.data_pointer) = value;
 			destination_.indicator = sizeof(double);
 		}
 
-		void operator()(boost::posix_time::ptime const & value)
+		void operator()(std::chrono::system_clock::time_point const & value)
 		{
-			auto const & date = value.date();
-			auto const & time = value.time_of_day();
-			auto destination = reinterpret_cast<SQL_TIMESTAMP_STRUCT *>(destination_.data_pointer);
-
-			destination->year = date.year();
-			destination->month = date.month();
-			destination->day = date.day();
-			destination->hour = time.hours();
-			destination->minute = time.minutes();
-			destination->second = time.seconds();
-			// map posix_time microsecond precision to SQL nanosecond precision
-			destination->fraction = time.fractional_seconds() * 1000;
+			auto tp = value;
+			auto dp = std::chrono::floor<std::chrono::days>(tp);
+			std::chrono::year_month_day ymd{dp};
+			auto time_of_day = tp - dp;
+			auto hrs   = std::chrono::duration_cast<std::chrono::hours>(time_of_day);
+			time_of_day -= hrs;
+			auto mins  = std::chrono::duration_cast<std::chrono::minutes>(time_of_day);
+			time_of_day -= mins;
+			auto secs  = std::chrono::duration_cast<std::chrono::seconds>(time_of_day);
+			time_of_day -= secs;
+			auto micros = std::chrono::duration_cast<std::chrono::microseconds>(time_of_day);
 
+			auto destination = reinterpret_cast<SQL_TIMESTAMP_STRUCT *>(destination_.data_pointer);
+			destination->year = static_cast<SQLSMALLINT>(int(ymd.year()));
+			destination->month = static_cast<SQLUSMALLINT>(unsigned(ymd.month()));
+			destination->day = static_cast<SQLUSMALLINT>(unsigned(ymd.day()));
+			destination->hour = static_cast<SQLUSMALLINT>(hrs.count());
+			destination->minute = static_cast<SQLUSMALLINT>(mins.count());
+			destination->second = static_cast<SQLUSMALLINT>(secs.count());
+			destination->fraction = static_cast<SQLUINTEGER>(micros.count() * 1000);
 			destination_.indicator = sizeof(SQL_TIMESTAMP_STRUCT);
 		}
 
-		void operator()(boost::gregorian::date const & value)
+		void operator()(std::chrono::year_month_day const & value)
 		{
 			auto destination = reinterpret_cast<SQL_DATE_STRUCT *>(destination_.data_pointer);
-
-			destination->year = value.year();
-			destination->month = value.month();
-			destination->day = value.day();
-
+			destination->year = static_cast<SQLSMALLINT>(int(value.year()));
+			destination->month = static_cast<SQLUSMALLINT>(unsigned(value.month()));
+			destination->day = static_cast<SQLUSMALLINT>(unsigned(value.day()));
 			destination_.indicator = sizeof(SQL_DATE_STRUCT);
 		}
 
@@ -114,13 +120,13 @@ namespace {
 
 bool parameter_is_suitable_for(parameter const & param, field const & value)
 {
-	return boost::apply_visitor(is_suitable_for(param), value);
+	return std::visit(is_suitable_for(param), value);
 }
 
 void set_field(field const & value, cpp_odbc::writable_buffer_element & destination)
 {
 	set_field_for visitor(destination);
-	boost::apply_visitor(visitor, value);
+	std::visit(visitor, value);
 }
 
 void set_null(cpp_odbc::writable_buffer_element & destination)

cpp/turbodbc/Library/src/result_sets/bound_result_set.cpp

@@ -5,6 +5,7 @@
 #include <turbodbc/buffer_size.h>
 
 #include <sqlext.h>
+#include <variant>
 
 namespace turbodbc { namespace result_sets {
 
@@ -21,7 +22,7 @@ namespace {
             descriptions.push_back(make_description(from_db, options));
         }
 
-        return boost::apply_visitor(turbodbc::determine_rows_to_buffer(descriptions), options.read_buffer_size);
+        return std::visit(turbodbc::determine_rows_to_buffer(descriptions), options.read_buffer_size);
     }
 
 }

cpp/turbodbc/Library/src/result_sets/double_buffered_result_set.cpp

@@ -4,7 +4,7 @@
 
 #include <turbodbc/buffer_size.h>
 
-#include <boost/variant.hpp>
+#include <variant>
 #include <sqlext.h>
 
 #include <future>
@@ -41,7 +41,7 @@ namespace {
 
     turbodbc::options options_with_half_read_buffer(turbodbc::options options)
     {
-        options.read_buffer_size = boost::apply_visitor(halve_buffer_size(), options.read_buffer_size);
+        options.read_buffer_size = std::visit(halve_buffer_size(), options.read_buffer_size);
         return options;
     }