Improvements for decimal_class: BigDecimal

Rakefile

@@ -94,7 +94,7 @@ task :check_env do
 end
 
 desc "Testing library (pure ruby)"
-task :test_pure => [ :set_env_pure, :check_env, :do_test_pure ]
+task :test_pure => [ :set_env_pure, :check_env, :do_test_pure, :do_test_additions_pure ]
 task(:set_env_pure) { ENV['JSON'] = 'pure' }
 
 UndocumentedTestTask.new do |t|
@@ -106,6 +106,15 @@ UndocumentedTestTask.new do |t|
   t.options = '-v'
 end
 
+UndocumentedTestTask.new do |t|
+  t.name = 'do_test_additions_pure'
+  t.libs << 'lib' << 'tests' << 'tests/lib'
+  t.ruby_opts << "-rhelper"
+  t.test_files = FileList['tests/additions/*_test.rb']
+  t.verbose = true
+  t.options = '-v'
+end
+
 desc "Testing library (pure ruby and extension)"
 task :test => [ :test_pure, :test_ext ]
 
@@ -174,7 +183,7 @@ if defined?(RUBY_ENGINE) and RUBY_ENGINE == 'jruby'
   end
 
   desc "Testing library (jruby)"
-  task :test_ext => [ :set_env_ext, :create_jar, :check_env, :do_test_ext ]
+  task :test_ext => [ :set_env_ext, :create_jar, :check_env, :do_test_ext, :do_test_additions_ext ]
   task(:set_env_ext) { ENV['JSON'] = 'ext' }
 
   UndocumentedTestTask.new do |t|
@@ -185,6 +194,14 @@ if defined?(RUBY_ENGINE) and RUBY_ENGINE == 'jruby'
     t.options = '-v'
   end
 
+  UndocumentedTestTask.new do |t|
+    t.name = 'do_test_additions_ext'
+    t.libs << 'lib' << 'tests'
+    t.test_files = FileList['tests/additions/*_test.rb']
+    t.verbose = true
+    t.options = '-v'
+  end
+
   file JRUBY_PARSER_JAR => :compile do
     cd 'java/src' do
       parser_classes = FileList[
@@ -249,7 +266,7 @@ else
   end
 
   desc "Testing library (extension)"
-  task :test_ext => [ :check_env, :compile, :do_test_ext ]
+  task :test_ext => [ :check_env, :compile, :do_test_ext, :do_test_additions_ext ]
 
   UndocumentedTestTask.new do |t|
     t.name = 'do_test_ext'
@@ -260,6 +277,15 @@ else
     t.options = '-v'
   end
 
+  UndocumentedTestTask.new do |t|
+    t.name = 'do_test_additions_ext'
+    t.libs << 'lib' << 'tests' << "tests/lib"
+    t.ruby_opts << '-rhelper'
+    t.test_files = FileList['tests/additions/*_test.rb']
+    t.verbose = true
+    t.options = '-v'
+  end
+
   desc "Generate parser with ragel"
   task :ragel => EXT_PARSER_SRC
 

ext/json/ext/generator/generator.c

@@ -1006,6 +1006,20 @@ static void generate_json_float(FBuffer *buffer, VALUE Vstate, JSON_Generator_St
     fbuffer_append_str(buffer, tmp);
 }
 
+static void generate_json_bigdecimal(FBuffer *buffer, VALUE Vstate, JSON_Generator_State *state, VALUE obj)
+{
+    char allow_nan = state->allow_nan;
+    VALUE tmp = rb_funcall(obj, i_to_s, 1, rb_str_new_cstr("F"));
+    if (!allow_nan) {
+        if (rb_funcall(obj, rb_intern("infinite?"), 0) == Qtrue || rb_funcall(obj, rb_intern("nan?"), 0) == Qtrue) {
+            fbuffer_free(buffer);
+            rb_raise(eGeneratorError, "%u: %"PRIsVALUE" not allowed in JSON", __LINE__, RB_OBJ_STRING(tmp));
+        }
+    }
+    rb_funcall(tmp, rb_intern("force_encoding"), 1, rb_str_new_cstr("ASCII"));
+    fbuffer_append_str(buffer, tmp);
+}
+
 static void generate_json(FBuffer *buffer, VALUE Vstate, JSON_Generator_State *state, VALUE obj)
 {
     VALUE tmp;
@@ -1028,6 +1042,8 @@ static void generate_json(FBuffer *buffer, VALUE Vstate, JSON_Generator_State *s
         generate_json_bignum(buffer, Vstate, state, obj);
     } else if (klass == rb_cFloat) {
         generate_json_float(buffer, Vstate, state, obj);
+    } else if (rb_str_equal(rb_class_name(klass), rb_str_new_cstr("BigDecimal"))) {
+        generate_json_bigdecimal(buffer, Vstate, state, obj);
     } else if (rb_respond_to(obj, i_to_json)) {
         tmp = rb_funcall(obj, i_to_json, 1, Vstate);
         Check_Type(tmp, T_STRING);

ext/json/ext/generator/generator.h

@@ -131,6 +131,7 @@ static void generate_json_integer(FBuffer *buffer, VALUE Vstate, JSON_Generator_
 static void generate_json_fixnum(FBuffer *buffer, VALUE Vstate, JSON_Generator_State *state, VALUE obj);
 static void generate_json_bignum(FBuffer *buffer, VALUE Vstate, JSON_Generator_State *state, VALUE obj);
 static void generate_json_float(FBuffer *buffer, VALUE Vstate, JSON_Generator_State *state, VALUE obj);
+static void generate_json_bigdecimal(FBuffer *buffer, VALUE Vstate, JSON_Generator_State *state, VALUE obj);
 static VALUE cState_partial_generate(VALUE self, VALUE obj);
 static VALUE cState_generate(VALUE self, VALUE obj);
 static VALUE cState_initialize(int argc, VALUE *argv, VALUE self);

ext/json/ext/parser/parser.c

@@ -2812,6 +2812,9 @@ static VALUE convert_encoding(VALUE source)
 *   defaults to false.
 * * *object_class*: Defaults to Hash
 * * *array_class*: Defaults to Array
+# * *decimal_class*: Specifies which class to use instead of the default
+#   (Float) when parsing decimal numbers. This class must accept a single
+#   string argument in its constructor.
 */
 static VALUE cParser_initialize(int argc, VALUE *argv, VALUE self)
 {

lib/json.rb

@@ -187,6 +187,19 @@
 #
 # ---
 #
+# Option +decimal_class+ (\Class) specifies which class to use when parsing
+# decimal numbers. This class must accept a single string argument in its
+# constructor. Defaults to Float. BigDecimal will preserve arbitrary precision.
+#
+# With the default, \Float:
+#   source = '3.141592653589793238462643383279'
+#   ruby = JSON.parse(source) # => 3.141592653589793
+# With \BigDecimal:
+#   ruby = JSON.parse(source, {decimal_class: BigDecimal})
+#   ruby # => 0.3141592653589793238462643383279e1
+#
+# ---
+#
 # Option +create_additions+ (boolean) specifies whether to use \JSON additions in parsing.
 # See {\JSON Additions}[#module-JSON-label-JSON+Additions].
 #

lib/json/pure/generator.rb

@@ -1,4 +1,5 @@
 #frozen_string_literal: false
+require "bigdecimal"
 module JSON
   MAP = {
     "\x0" => '\u0000',
@@ -407,6 +408,16 @@ def to_json(state = nil, *)
           end
         end
 
+        module BigDecimal
+          # Returns a JSON string representation for this BigDecimal as a JSON number.
+          def to_json(state = nil, *)
+            if (infinite? || nan?) && !State.from_state(state).allow_nan?
+              raise GeneratorError, "#{self} not allowed in JSON"
+            end
+            to_s("F").force_encoding(Encoding::ASCII)
+          end
+        end
+
         module String
           # This string should be encoded with UTF-8 A call to this method
           # returns a JSON string encoded with UTF16 big endian characters as

tests/json_generator_test.rb

@@ -85,6 +85,14 @@ def test_generate_pretty
     assert_equal '666', pretty_generate(666)
   end
 
+  def test_generate_bigdecimal
+    bd_s = '3.141592653589793238462643383279'
+    bd = BigDecimal(bd_s)
+    assert_equal(bd_s, generate(bd))
+    assert_equal(bd_s, pretty_generate(bd))
+    assert_equal(bd, parse(generate(bd), decimal_class: BigDecimal))
+  end
+
   def test_generate_custom
     state = State.new(:space_before => " ", :space => "   ", :indent => "<i>", :object_nl => "\n", :array_nl => "<a_nl>")
     json = generate({1=>{2=>3,4=>[5,6]}}, state)