Function copy

modules/llrt_buffer/src/buffer.rs:319–354

Prototype Methods

(
    this: This<Object<'js>>,
    ctx: Ctx<'js>,
    target: ObjectBytes<'js>,
    args: Rest<usize>,
)

// Prototype Methods
fn copy<'js>(
    this: This<Object<'js>>,
    ctx: Ctx<'js>,
    target: ObjectBytes<'js>,
    args: Rest<usize>,
) -> Result<usize> {
    let mut args_iter = args.0.into_iter();
    let target_start = args_iter.next().unwrap_or_default();
    let source_start = args_iter.next().unwrap_or_default();
    let source_end = args_iter.next().unwrap_or_else(|| this.0.len());

    let mut copyable_length = 0;

    if source_start >= source_end {
        return Ok(copyable_length);
    }

    let source_bytes = ObjectBytes::from(&ctx, this.0.as_inner())?;
    let source_bytes = source_bytes.as_bytes(&ctx)?;

    if let Some((array_buffer, _, _)) = target.get_array_buffer()? {
        let raw = array_buffer
            .as_raw()
            .ok_or(ERROR_MSG_ARRAY_BUFFER_DETACHED)
            .or_throw(&ctx)?;

        let target_bytes = unsafe { slice::from_raw_parts_mut(raw.ptr.as_ptr(), raw.len) };

        copyable_length = (source_end - source_start).min(raw.len - target_start);

        target_bytes[target_start..target_start + copyable_length]
            .copy_from_slice(&source_bytes[source_start..source_start + copyable_length]);
    }

    Ok(copyable_length)
}

fn subarray<'js>(
    this: This<Object<'js>>,