diff options
| -rw-r--r-- | ctru-rs/src/applet/swkbd.rs | 48 |
1 files changed, 21 insertions, 27 deletions
diff --git a/ctru-rs/src/applet/swkbd.rs b/ctru-rs/src/applet/swkbd.rs index 27b08ee..7f3dcfd 100644 --- a/ctru-rs/src/applet/swkbd.rs +++ b/ctru-rs/src/applet/swkbd.rs @@ -96,7 +96,8 @@ impl Swkbd { /// Gets input from this keyboard and appends it to the provided string. /// - /// The text received from the keyboard can be up to 2048 bytes in length. + /// The text received from the keyboard will be truncated if it is greater than 2048 bytes + /// in length. pub fn get_utf8(&mut self, buf: &mut String) -> Result<Button, Error> { // Unfortunately the libctru API doesn't really provide a way to get the exact length // of the string that it receieves from the software keyboard. Instead it expects you @@ -104,40 +105,33 @@ impl Swkbd { // you have to set some upper limit on the potential size of the user's input. const MAX_BYTES: usize = 2048; let mut tmp = [0u8; MAX_BYTES]; - let button = unsafe { self.get_bytes(&mut tmp)? }; + let button = self.get_bytes(&mut tmp)?; - // Make sure we haven't overflowed our buffer. libctru might already check this, - // but we'll do it here too just in case + // libctru does, however, seem to ensure that the buffer will always contain a properly + // terminated UTF-8 sequence even if the input has to be truncated, so these operations + // should be safe. let len = unsafe { libc::strlen(tmp.as_ptr()) }; - assert!(len <= MAX_BYTES); + let utf8 = unsafe { str::from_utf8_unchecked(&tmp[..len]) }; - // Not sure if this is falliable or not in this stage of the process, - // but catch any decoding errors to be sure - let utf8 = match str::from_utf8(&tmp[..len]) { - Ok(parsed) => parsed, - Err(_) => return Err(Error::InvalidInput), - }; - - // Finally, copy the validated input into the user's `String` + // Copy the input into the user's `String` *buf += utf8; Ok(button) } - /// Fills the provided buffer with a NUL-terminated sequence of bytes from the software - /// keyboard - /// - /// # Unsafety + /// Fills the provided buffer with a UTF-8 encoded, NUL-terminated sequence of bytes from + /// this software keyboard. /// - /// The received bytes are nominally UTF-8 formatted, but the provided buffer must be large - /// enough to receive both the text from the software keyboard along with a NUL-terminator. - /// Otherwise undefined behavior can result. - pub unsafe fn get_bytes(&mut self, buf: &mut [u8]) -> Result<Button, Error> { - match swkbdInputText(self.state.as_mut(), buf.as_mut_ptr(), buf.len()) { - libctru::SWKBD_BUTTON_NONE => Err(self.parse_swkbd_error()), - libctru::SWKBD_BUTTON_LEFT => Ok(Button::Left), - libctru::SWKBD_BUTTON_MIDDLE => Ok(Button::Middle), - libctru::SWKBD_BUTTON_RIGHT => Ok(Button::Right), - _ => unreachable!(), + /// If the buffer is too small to contain the entire sequence received from the keyboard, + /// the output will be truncated but should still be well-formed UTF-8 + pub fn get_bytes(&mut self, buf: &mut [u8]) -> Result<Button, Error> { + unsafe { + match swkbdInputText(self.state.as_mut(), buf.as_mut_ptr(), buf.len()) { + libctru::SWKBD_BUTTON_NONE => Err(self.parse_swkbd_error()), + libctru::SWKBD_BUTTON_LEFT => Ok(Button::Left), + libctru::SWKBD_BUTTON_MIDDLE => Ok(Button::Middle), + libctru::SWKBD_BUTTON_RIGHT => Ok(Button::Right), + _ => unreachable!(), + } } } |