fast coercion date and time

Gemfile

@@ -23,5 +23,6 @@ group :benchmarks do
     gem "fast_attributes"
     gem "hotch"
     gem "virtus"
+    gem "activemodel"
   end
 end

benchmarks/coercions_date.rb

@@ -0,0 +1,48 @@
+# frozen_string_literal: true
+
+require "active_model"
+require "benchmark/ips"
+require "dry/types"
+
+am = ActiveModel::Type::Date.new
+dry = Dry::Types["params.date"]
+
+["2020-01-20", "3rd Feb 2001"].each do |d|
+  Benchmark.ips do |x|
+    x.report("DRY #{d}") do |n|
+      while n > 0
+        dry[d]
+        n -= 1
+      end
+    end
+
+    x.report("AM #{d}") do |n|
+      while n > 0
+        am.cast(d)
+        n -= 1
+      end
+    end
+
+    x.compare!
+  end
+end
+
+# before
+#
+# Comparison:
+#        AM 2020-01-20:   712594.2 i/s
+#       DRY 2020-01-20:   234735.9 i/s - 3.04x  (± 0.00) slower
+#
+# Comparison:
+#     DRY 3rd Feb 2001:   148000.4 i/s
+#      AM 3rd Feb 2001:   140262.5 i/s - same-ish: difference falls within error
+
+# after
+#
+# Comparison:
+#        AM 2020-01-20:   694511.8 i/s
+#       DRY 2020-01-20:   692906.6 i/s - same-ish: difference falls within error
+#
+# Comparison:
+#     DRY 3rd Feb 2001:   141146.9 i/s
+#      AM 3rd Feb 2001:   139686.5 i/s - same-ish: difference falls within error

benchmarks/coercions_time.rb

@@ -0,0 +1,60 @@
+# frozen_string_literal: true
+
+require "benchmark/ips"
+require "dry/types"
+require "active_model"
+require "active_support/core_ext/time/zones"
+require 'pry'
+
+::Time.zone_default = "Moscow"
+am = ActiveModel::Type::Time.new
+dry = Dry::Types["params.time"]
+
+["2020-01-20 19:40:22", "2021-02-03T00:10:54.597+03:00", "Thu Nov 29 14:33:20 2001"].each do |d|
+  Benchmark.ips do |x|
+    x.report("DRY #{d}") do |n|
+      while n > 0
+        dry[d]
+        n -= 1
+      end
+    end
+
+    x.report("AM #{d}") do |n|
+      while n > 0
+        am.cast(d)
+        n -= 1
+      end
+    end
+
+    x.compare!
+  end
+end
+
+
+# before
+#
+# Comparison:
+# AM 2020-01-20 19:40:22:   130660.9 i/s
+# DRY 2020-01-20 19:40:22:    58853.9 i/s - 2.22x  (± 0.00) slower
+#
+# Comparison:
+# DRY 2021-02-03T00:10:54.597+03:00:    52110.0 i/s
+# AM 2021-02-03T00:10:54.597+03:00:    39652.9 i/s - 1.31x  (± 0.00) slower
+#
+# Comparison:
+# DRY Thu Nov 29 14:33:20 2001:    44819.1 i/s
+# AM Thu Nov 29 14:33:20 2001:    33064.5 i/s - 1.36x  (± 0.00) slower
+
+# after
+#
+# Comparison:
+# DRY 2020-01-20 19:40:22:   190951.9 i/s
+# AM 2020-01-20 19:40:22:   131920.6 i/s - 1.45x  (± 0.00) slower
+#
+# Comparison:
+# DRY 2021-02-03T00:10:54.597+03:00:   157549.5 i/s
+# AM 2021-02-03T00:10:54.597+03:00:    40502.8 i/s - 3.89x  (± 0.00) slower
+#
+# Comparison:
+# DRY Thu Nov 29 14:33:20 2001:    44376.3 i/s
+# AM Thu Nov 29 14:33:20 2001:    33955.3 i/s - 1.31x  (± 0.00) slower

lib/dry/types/coercions.rb

@@ -18,7 +18,7 @@ module Coercions
       def to_date(input, &block)
         if input.respond_to?(:to_str)
           begin
-            ::Date.parse(input)
+            fast_string_to_date(input) || ::Date.parse(input)
           rescue ArgumentError, RangeError => e
             CoercionError.handle(e, &block)
           end
@@ -64,7 +64,7 @@ def to_date_time(input, &block)
       def to_time(input, &block)
         if input.respond_to?(:to_str)
           begin
-            ::Time.parse(input)
+            fast_string_to_time(input) || ::Time.parse(input)
           rescue ArgumentError => e
             CoercionError.handle(e, &block)
           end
@@ -102,6 +102,37 @@ def to_symbol(input, &block)
       def empty_str?(value)
         EMPTY_STRING.eql?(value)
       end
+
+      ISO_DATE = /\A(\d{4})-(\d\d)-(\d\d)\z/
+      def fast_string_to_date(string)
+        if string =~ ISO_DATE
+          ::Date.new $1.to_i, $2.to_i, $3.to_i
+        end
+      end
+
+      ISO_DATETIME = /
+        \A
+        (\d{4})-(\d\d)-(\d\d)(?:T|\s)            # 2020-06-20T
+        (\d\d):(\d\d):(\d\d)(?:\.(\d{1,6})\d*)?  # 10:20:30.123456
+        (?:(Z(?=\z)|[+-]\d\d)(?::?(\d\d))?)?     # +09:00
+        \z
+      /x
+      def fast_string_to_time(string)
+        return unless ISO_DATETIME =~ string
+
+        usec = $7.to_i
+        usec_len = $7&.length
+        if usec_len&.< 6
+          usec *= 10**(6 - usec_len)
+        end
+
+        if $8
+          offset = $8 == "Z" ? 0 : $8.to_i * 3600 + $9.to_i * 60
+        end
+
+        ::Time.local($1.to_i, $2.to_i, $3.to_i, $4.to_i, $5.to_i, $6.to_i, usec, offset)
+      end
+
     end
   end
 end