September 2017 Update

Task/Call-a-foreign-language-function/Ruby/call-a-foreign-language-function-1.rb

@@ -1,14 +1,34 @@
-require 'ffi'
+/* rc_strdup.c */
+#include <stdlib.h>   /* free() */
+#include <string.h>   /* strdup() */
+#include <ruby.h>
 
-module LibC
-  extend FFI::Library
-  ffi_lib FFI::Platform::LIBC
+static VALUE
+rc_strdup(VALUE obj, VALUE str_in)
+{
+    VALUE str_out;
+    char *c, *d;
 
-  attach_function :strdup, [:string], :pointer
-  attach_function :free, [:pointer], :void
-end
+    /*
+     * Convert Ruby value to C string.  May raise TypeError if the
+     * value isn't a string, or ArgumentError if it contains '\0'.
+     */
+    c = StringValueCStr(str_in);
 
-string = "Hello, World!"
-duplicate = LibC.strdup(string)
-puts duplicate.get_string(0)
-LibC.free(duplicate)
+    /* Call strdup() and perhaps raise Errno::ENOMEM. */
+    d = strdup(c);
+    if (d == NULL)
+	rb_sys_fail(NULL);
+
+    /* Convert C string to Ruby string. */
+    str_out = rb_str_new_cstr(d);
+    free(d);
+    return str_out;
+}
+
+void
+Init_rc_strdup(void)
+{
+    VALUE mRosettaCode = rb_define_module("RosettaCode");
+    rb_define_module_function(mRosettaCode, "strdup", rc_strdup, 1);
+}

Task/Call-a-foreign-language-function/Ruby/call-a-foreign-language-function-2.rb

@@ -1,19 +1,3 @@
-require 'dl'
-require 'fiddle'
-
-# Declare strdup().
-#  * DL::Handle['strdup'] is the address of the function.
-#  * The function takes a pointer and returns a pointer.
-strdup = Fiddle::Function.new(DL::Handle['strdup'],
-                              [DL::TYPE_VOIDP], DL::TYPE_VOIDP)
-
-# Call strdup().
-#  * Fiddle converts our Ruby string to a C string.
-#  * Fiddle returns a DL::CPtr.
-duplicate = strdup.call("This is a string!")
-
-# DL::CPtr#to_s converts our C string to a Ruby string.
-puts duplicate.to_s
-
-# We must call free(), because strdup() allocated memory.
-DL.free duplicate
+# extconf.rb
+require 'mkmf'
+create_makefile('rc_strdup')

Task/Call-a-foreign-language-function/Ruby/call-a-foreign-language-function-3.rb

@@ -1,33 +1,3 @@
-require 'rubygems'
-require 'inline'
-
-class InlineTester
-  def factorial_ruby(n)
-    (1..n).inject(1, :*)
-  end
-
-  inline do |builder|
-    builder.c <<-'END_C'
-      long factorial_c(int max) {
-        long result = 1;
-        int i;
-        for (i = 1; i <= max; ++i)
-          result *= i;
-        return result;
-      }
-    END_C
-  end
-
-  inline do |builder|
-    builder.include %q("math.h")
-    builder.c <<-'END_C'
-      int my_ilogb(double value) {
-        return ilogb(value);
-      }
-    END_C
-  end
-end
-
-t = InlineTester.new
-11.upto(14) {|n| p [n, t.factorial_ruby(n), t.factorial_c(n)]}
-p t.my_ilogb(1000)
+# demo.rb
+require 'rc_strdup'
+puts RosettaCode.strdup('This string gets duplicated.')

Task/Call-a-foreign-language-function/Ruby/call-a-foreign-language-function-4.rb

@@ -0,0 +1,14 @@
+require 'ffi'
+
+module LibC
+  extend FFI::Library
+  ffi_lib FFI::Platform::LIBC
+
+  attach_function :strdup, [:string], :pointer
+  attach_function :free, [:pointer], :void
+end
+
+string = "Hello, World!"
+duplicate = LibC.strdup(string)
+puts duplicate.get_string(0)
+LibC.free(duplicate)

Task/Call-a-foreign-language-function/Ruby/call-a-foreign-language-function-5.rb

@@ -0,0 +1,13 @@
+require 'fiddle'
+
+# Find strdup().  It takes a pointer and returns a pointer.
+strdup = Fiddle::Function
+           .new(Fiddle::Handle['strdup'],
+                [Fiddle::TYPE_VOIDP], Fiddle::TYPE_VOIDP)
+
+# Call strdup().
+#   - It converts our Ruby string to a C string.
+#   - It returns a Fiddle::Pointer.
+duplicate = strdup.call("This is a string!")
+puts duplicate.to_s     # Convert the C string to a Ruby string.
+Fiddle.free duplicate   # free() the memory that strdup() allocated.

Task/Call-a-foreign-language-function/Ruby/call-a-foreign-language-function-6.rb

@@ -0,0 +1,12 @@
+require 'fiddle'
+require 'fiddle/import'
+
+module C
+  extend Fiddle::Importer
+  dlload Fiddle::Handle::DEFAULT
+  extern 'char *strdup(char *)'
+end
+
+duplicate = C.strdup("This is a string!")
+puts duplicate.to_s
+Fiddle.free duplicate

Task/Call-a-foreign-language-function/Ruby/call-a-foreign-language-function-7.rb

@@ -0,0 +1,33 @@
+require 'rubygems'
+require 'inline'
+
+class InlineTester
+  def factorial_ruby(n)
+    (1..n).inject(1, :*)
+  end
+
+  inline do |builder|
+    builder.c <<-'END_C'
+      long factorial_c(int max) {
+        long result = 1;
+        int i;
+        for (i = 1; i <= max; ++i)
+          result *= i;
+        return result;
+      }
+    END_C
+  end
+
+  inline do |builder|
+    builder.include %q("math.h")
+    builder.c <<-'END_C'
+      int my_ilogb(double value) {
+        return ilogb(value);
+      }
+    END_C
+  end
+end
+
+t = InlineTester.new
+11.upto(14) {|n| p [n, t.factorial_ruby(n), t.factorial_c(n)]}
+p t.my_ilogb(1000)