Merge pull request #2372 from herwinw/securerandom_random_bytes

Implement Securerandom.random_bytes

lib/securerandom.cpp

@@ -0,0 +1,79 @@
+#include "natalie.hpp"
+#include <random>
+
+using namespace Natalie;
+
+static Value generate_random(double min, double max) {
+    std::random_device rd;
+    std::uniform_real_distribution<double> random_number(min, max);
+    return new FloatObject { random_number(rd) };
+}
+
+static Value generate_random(nat_int_t min, nat_int_t max) {
+    std::random_device rd;
+    std::uniform_int_distribution<nat_int_t> random_number(min, max);
+    return Value::integer(random_number(rd));
+}
+
+Value SecureRandom_random_number(Env *env, Value self, Args &&args, Block *) {
+    args.ensure_argc_between(env, 0, 1);
+    auto arg = args.at(0, NilObject::the());
+    if (arg->is_nil()) {
+        return generate_random(0.0, 1.0);
+    } else {
+        if (arg->is_float()) {
+            double max = arg->as_float()->to_double();
+            if (max <= 0) {
+                env->raise("ArgumentError", "invalid argument - {}", arg->inspect_str(env));
+            }
+            return generate_random(0.0, max);
+        } else if (arg->is_range()) {
+            Value min = arg->as_range()->begin();
+            Value max = arg->as_range()->end();
+            // TODO: There can be different types of objects that respond to + and - (according to the docs)
+            // I'm not sure how we should handle those though (coerce via to_int or to_f?)
+            if (min->is_numeric() && max->is_numeric()) {
+                if (min.send(env, ">"_s, { max })->is_true()) {
+                    env->raise("ArgumentError", "invalid argument - {}", arg->inspect_str(env));
+                }
+
+                if (min->is_float() || max->is_float()) {
+                    double min_rand, max_rand;
+                    if (min->is_float()) {
+                        min_rand = min->as_float()->to_double();
+                    } else {
+                        min_rand = static_cast<double>(IntegerObject::convert_to_native_type<nat_int_t>(env, min));
+                    }
+
+                    if (max->is_float()) {
+                        max_rand = max->as_float()->to_double();
+                    } else {
+                        max_rand = static_cast<double>(IntegerObject::convert_to_native_type<nat_int_t>(env, max));
+                    }
+
+                    return generate_random(min_rand, max_rand);
+                } else {
+                    nat_int_t min_rand = IntegerObject::convert_to_native_type<nat_int_t>(env, min);
+                    nat_int_t max_rand = IntegerObject::convert_to_native_type<nat_int_t>(env, max);
+
+                    if (arg->as_range()->exclude_end()) {
+                        max_rand -= 1;
+                    }
+
+                    return generate_random(min_rand, max_rand);
+                }
+            }
+            env->raise("ArgumentError", "bad value for range");
+        }
+
+        nat_int_t max = IntegerObject::convert_to_nat_int_t(env, arg);
+        if (max <= 0) {
+            env->raise("ArgumentError", "invalid argument - {}", arg->inspect_str(env));
+        }
+        return generate_random(0, max - 1);
+    }
+}
+
+Value init_securerandom(Env *env, Value self) {
+    return NilObject::the();
+}

lib/securerandom.rb

@@ -1,8 +1,13 @@
+require 'natalie/inline'
+require 'securerandom.cpp'
+
 require 'random/formatter'
 
 class SecureRandom
   extend Random::Formatter
 
+  __bind_static_method__ :random_number, :SecureRandom_random_number
+
   def self.bytes(n)
     Random.urandom(n)
   end

spec/library/securerandom/random_number_spec.rb

@@ -0,0 +1,107 @@
+require_relative '../../spec_helper'
+require_relative '../../core/random/shared/rand'
+
+require 'securerandom'
+
+describe "SecureRandom.random_number" do
+  it_behaves_like :random_number, :rand, SecureRandom
+  it_behaves_like :random_number, :random_number, SecureRandom
+
+  it "generates a random positive number smaller then the positive integer argument" do
+    (1..64).each do |idx|
+      num = SecureRandom.random_number(idx)
+      num.should be_kind_of(Integer)
+      0.should <= num
+      num.should < idx
+    end
+  end
+
+  it "generates a random (potentially bignum) integer value for bignum argument" do
+    max = 12345678901234567890
+    NATFIXME 'it generates a random (potentially bignum) integer value for bignum argument', exception: RangeError, message: "bignum too big to convert into `long'" do
+      11.times do
+        num = SecureRandom.random_number max
+        num.should be_kind_of(Integer)
+        0.should <= num
+        num.should < max
+      end
+    end
+  end
+
+  it "generates a random float number between 0.0 and 1.0 if no argument provided" do
+    64.times do
+      num = SecureRandom.random_number
+      num.should be_kind_of(Float)
+      0.0.should <= num
+      num.should < 1.0
+    end
+  end
+
+  it "generates a random value in given (integer) range limits" do
+    64.times do
+      num = SecureRandom.random_number 11...13
+      num.should be_kind_of(Integer)
+      11.should <= num
+      num.should < 13
+    end
+  end
+
+  it "generates a random value in given big (integer) range limits" do
+    lower = 12345678901234567890
+    upper = 12345678901234567890 + 5
+    NATFIXME 'it generates a random value in given big (integer) range limits', exception: RangeError, message: "bignum too big to convert into `long long int'" do
+      32.times do
+        num = SecureRandom.random_number lower..upper
+        num.should be_kind_of(Integer)
+        lower.should <= num
+        num.should <= upper
+      end
+    end
+  end
+
+  it "generates a random value in given (float) range limits" do
+    64.times do
+      num = SecureRandom.random_number 0.6..0.9
+      num.should be_kind_of(Float)
+      0.6.should <= num
+      num.should <= 0.9
+    end
+  end
+
+  it "generates a random float number between 0.0 and 1.0 if argument is negative" do
+    NATFIXME 'it generates a random float number between 0.0 and 1.0 if argument is negative', exception: ArgumentError, message: 'invalid argument - -10' do
+      num = SecureRandom.random_number(-10)
+      num.should be_kind_of(Float)
+      0.0.should <= num
+      num.should < 1.0
+    end
+  end
+
+  it "generates a random float number between 0.0 and 1.0 if argument is negative float" do
+    NATFIXME 'it generates a random float number between 0.0 and 1.0 if argument is negative float', exception: ArgumentError, message: 'invalid argument - -11.1' do
+      num = SecureRandom.random_number(-11.1)
+      num.should be_kind_of(Float)
+      0.0.should <= num
+      num.should < 1.0
+    end
+  end
+
+  it "generates different float numbers with subsequent invocations" do
+    # quick and dirty check, but good enough
+    values = []
+    256.times do
+      val = SecureRandom.random_number
+      # make sure the random values are not repeating
+      values.should_not include(val)
+      values << val
+    end
+  end
+
+  it "raises ArgumentError if the argument is non-numeric" do
+    NATFIXME 'it raises ArgumentError if the argument is non-numeric', exception: SpecFailedException do
+      -> {
+        SecureRandom.random_number(Object.new)
+      }.should raise_error(ArgumentError)
+    end
+  end
+end

src/random_object.cpp

@@ -58,19 +58,19 @@ Value RandomObject::rand(Env *env, Value arg) {
                     if (min->is_float()) {
                         min_rand = min->as_float()->to_double();
                     } else {
-                        min_rand = (double)min->as_integer()->to_nat_int_t();
+                        min_rand = static_cast<double>(IntegerObject::convert_to_native_type<nat_int_t>(env, min));
                     }
 
                     if (max->is_float()) {
                         max_rand = max->as_float()->to_double();
                     } else {
-                        max_rand = (double)max->as_integer()->to_nat_int_t();
+                        max_rand = static_cast<double>(IntegerObject::convert_to_native_type<nat_int_t>(env, max));
                     }
 
                     return generate_random(min_rand, max_rand);
                 } else {
-                    nat_int_t min_rand = min->as_integer()->to_nat_int_t();
-                    nat_int_t max_rand = max->as_integer()->to_nat_int_t();
+                    auto min_rand = IntegerObject::convert_to_native_type<nat_int_t>(env, min);
+                    auto max_rand = IntegerObject::convert_to_native_type<nat_int_t>(env, max);
 
                     if (arg->as_range()->exclude_end()) {
                         max_rand -= 1;