Method: DataView.new

Defined in:
ext/type_array/data_view.c

.new(buf) ⇒ DataView .new("buffer") ⇒ DataView

Creates a new DataView instance. Both ArrayBuffer and data (String) constructors are supported.

Examples

buf = ArrayBuffer.new(8)         =>  ArrayBuffer
view = DataView.new(buf)         =>  DataView

view = DataView.new(buf, 2)      =>  DataView
view.byte_offset                 => 2
view.byte_length                 => 6

view = DataView.new(buf, 2, 4)   =>  DataView
view.byte_offset                 => 2
view.byte_length                 => 2

view = DataView.new("buffer")    =>  DataView

Overloads:



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# File 'ext/type_array/data_view.c', line 74

static VALUE rb_data_view_s_new(int argc, VALUE *argv, VALUE klass)
{
    VALUE data_view;
    unsigned long new_byte_length;
    rb_data_view_t *view = NULL;
    VALUE obj, byte_offset, byte_length, buffer;
    new_byte_length = 0;
    rb_scan_args(argc, argv, "12", &obj, &byte_offset, &byte_length);
    data_view = Data_Make_Struct(klass, rb_data_view_t, rb_mark_data_view, rb_free_data_view, view);
    view->byte_offset = 0;
    view->byte_length = 0;
    if (rb_class_of(obj) == rb_cArrayBuffer) {
        GetArrayBuffer(obj);
        view->byte_length = buf->length;
        view->buf = obj;
    } else if (rb_type(obj) == T_STRING){
        ArrayBufferEncode(obj);
        buffer = rb_alloc_array_buffer((unsigned long)RSTRING_LEN(obj), (void *)RSTRING_PTR(obj));
        GetArrayBuffer(buffer);
        view->byte_length = buf->length;
        view->buf = buffer;
    } else {
        rb_raise(rb_eTypeError, "DataView constructor %s not supported.", RSTRING_PTR(rb_obj_as_string(obj)));
    }
    if (!NIL_P(byte_offset)) {
        Check_Type(byte_offset, T_FIXNUM);
         view->byte_offset = FIX2ULONG(byte_offset);
         if (view->byte_offset >= view->byte_length)
            rb_raise(rb_eRangeError, "Byte offset out of range.");
    }
    if (!NIL_P(byte_length)) {
        Check_Type(byte_length, T_FIXNUM);
        new_byte_length = FIX2ULONG(byte_length);
        if (new_byte_length > view->byte_length)
            rb_raise(rb_eRangeError, "Byte length out of range.");
        if ((view->byte_offset + new_byte_length) > view->byte_length)
            rb_raise(rb_eRangeError, "Byte offset / length is not aligned.");
        view->byte_length = new_byte_length;
    }
    view->byte_length -= view->byte_offset;
    rb_obj_call_init(data_view, 0, NULL);
    return data_view;
}