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instance method

IO::Buffer::Slice#initialize_copy

dup → slice

clone → slice

static VALUE
io_buffer_slice_initialize_copy(VALUE self, VALUE other)
{
    if (self == other) return self;
    rb_check_frozen(self);
    struct rb_io_buffer_view *slice = get_io_buffer_view(self);
    const struct rb_io_buffer_view *original = get_io_buffer_view(other);
    if (!io_buffer_slice_p(original)) rb_raise(rb_eTypeError, "Expected IO::Buffer::Slice!");
    if (!NIL_P(slice->source)) rb_raise(rb_eRuntimeError, "Slice is already initialized!");

    slice->base = original->base;
    slice->size = original->size;
    slice->flags = original->flags;
    RB_OBJ_WRITE(self, &slice->source, original->source);
    return self;
}

Copies the view, retaining the same source, offset, and size without copying the underlying bytes. Advancing or resizing the copy does not change the original view; writes through either view affect shared storage.

Example

buffer = IO::Buffer.new(6)
buffer.set_string("abcdef")
slice = buffer.slice(1, 3)
copy = slice.dup
copy.source.equal?(slice.source) # => true
copy.advance(1)
copy.get_string                 # => "cd"
slice.get_string                # => "bcd"
copy.set_string("XY")
buffer.get_string               # => "abXYef"

This differs from IO::Buffer::Storage#dup, which copies the bytes into independent storage. The usual Object#dup and Object#clone frozen-state rules apply.