diff --git a/ext/fiddle/pointer.c b/ext/fiddle/pointer.c index 15107e38..5c71967a 100644 --- a/ext/fiddle/pointer.c +++ b/ext/fiddle/pointer.c @@ -799,6 +799,33 @@ rb_fiddle_ptr_s_to_ptr(VALUE self, VALUE val) return ptr; } +/* + * call-seq: + * Fiddle::Pointer.read(address, len) => string + * + * Or read the memory at address +address+ with length +len+ and return a + * string with that memory + */ + +static VALUE +rb_fiddle_ptr_read_mem(VALUE klass, VALUE address, VALUE len) +{ + return rb_str_new((char *)NUM2PTR(address), NUM2ULONG(len)); +} + +/* + * call-seq: + * Fiddle::Pointer.write(address, str) + * + * Write bytes in +str+ to the location pointed to by +address+. + */ +static VALUE +rb_fiddle_ptr_write_mem(VALUE klass, VALUE addr, VALUE str) +{ + memcpy(NUM2PTR(addr), StringValuePtr(str), RSTRING_LEN(str)); + return str; +} + void Init_fiddle_pointer(void) { @@ -815,6 +842,8 @@ Init_fiddle_pointer(void) rb_define_singleton_method(rb_cPointer, "malloc", rb_fiddle_ptr_s_malloc, -1); rb_define_singleton_method(rb_cPointer, "to_ptr", rb_fiddle_ptr_s_to_ptr, 1); rb_define_singleton_method(rb_cPointer, "[]", rb_fiddle_ptr_s_to_ptr, 1); + rb_define_singleton_method(rb_cPointer, "read", rb_fiddle_ptr_read_mem, 2); + rb_define_singleton_method(rb_cPointer, "write", rb_fiddle_ptr_write_mem, 2); rb_define_method(rb_cPointer, "initialize", rb_fiddle_ptr_initialize, -1); rb_define_method(rb_cPointer, "free=", rb_fiddle_ptr_free_set, 1); rb_define_method(rb_cPointer, "free", rb_fiddle_ptr_free_get, 0); diff --git a/test/fiddle/test_pointer.rb b/test/fiddle/test_pointer.rb index d6cba04b..f2c1d285 100644 --- a/test/fiddle/test_pointer.rb +++ b/test/fiddle/test_pointer.rb @@ -10,6 +10,22 @@ def dlwrap arg Fiddle.dlwrap arg end + def test_can_read_write_memory + # Allocate some memory + address = Fiddle.malloc(Fiddle::SIZEOF_VOIDP) + + bytes_to_write = Fiddle::SIZEOF_VOIDP.times.to_a.pack("C*") + + # Write to the memory + Fiddle::Pointer.write(address, bytes_to_write) + + # Read the bytes out again + bytes = Fiddle::Pointer.read(address, Fiddle::SIZEOF_VOIDP) + assert_equal bytes_to_write, bytes + ensure + Fiddle.free address + end + def test_cptr_to_int null = Fiddle::NULL assert_equal(null.to_i, null.to_int)