use crate::descriptor::descriptor_type; use crate::driver::EndpointAddress; use crate::types::InterfaceNumber; #[derive(Copy, Clone, PartialEq, Eq, Debug)] #[cfg_attr(feature = "defmt", derive(defmt::Format))] pub struct ReadError; pub struct Reader<'a> { data: &'a [u8], } impl<'a> Reader<'a> { pub const fn new(data: &'a [u8]) -> Self { Self { data } } pub const fn eof(&self) -> bool { self.data.is_empty() } pub fn read(&mut self) -> Result<[u8; N], ReadError> { let n = self.data.get(0..N).ok_or(ReadError)?; self.data = &self.data[N..]; Ok(n.try_into().unwrap()) } pub fn read_u8(&mut self) -> Result { Ok(u8::from_le_bytes(self.read()?)) } pub fn read_u16(&mut self) -> Result { Ok(u16::from_le_bytes(self.read()?)) } pub fn read_slice(&mut self, len: usize) -> Result<&'a [u8], ReadError> { let res = self.data.get(0..len).ok_or(ReadError)?; self.data = &self.data[len..]; Ok(res) } pub fn read_descriptors(&mut self) -> DescriptorIter<'_, 'a> { DescriptorIter { r: self } } } pub struct DescriptorIter<'a, 'b> { r: &'a mut Reader<'b>, } impl<'a, 'b> Iterator for DescriptorIter<'a, 'b> { type Item = Result<(u8, Reader<'a>), ReadError>; fn next(&mut self) -> Option { if self.r.eof() { return None; } let len = match self.r.read_u8() { Ok(x) => x, Err(e) => return Some(Err(e)), }; let type_ = match self.r.read_u8() { Ok(x) => x, Err(e) => return Some(Err(e)), }; let data = match self.r.read_slice(len as usize - 2) { Ok(x) => x, Err(e) => return Some(Err(e)), }; Some(Ok((type_, Reader::new(data)))) } } #[derive(Copy, Clone, PartialEq, Eq, Debug)] #[cfg_attr(feature = "defmt", derive(defmt::Format))] pub struct EndpointInfo { pub configuration: u8, pub interface: InterfaceNumber, pub interface_alt: u8, pub ep_address: EndpointAddress, } pub fn foreach_endpoint(data: &[u8], mut f: impl FnMut(EndpointInfo)) -> Result<(), ReadError> { let mut ep = EndpointInfo { configuration: 0, interface: InterfaceNumber(0), interface_alt: 0, ep_address: EndpointAddress::from(0), }; for res in Reader::new(data).read_descriptors() { let (kind, mut r) = res?; match kind { descriptor_type::CONFIGURATION => { let _total_length = r.read_u16()?; let _total_length = r.read_u8()?; ep.configuration = r.read_u8()?; } descriptor_type::INTERFACE => { ep.interface = InterfaceNumber(r.read_u8()?); ep.interface_alt = r.read_u8()?; } descriptor_type::ENDPOINT => { ep.ep_address = EndpointAddress::from(r.read_u8()?); f(ep); } _ => {} } } Ok(()) }