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|
use std::fmt::Display;
use crate::messages::MessageSkipperError;
/// Message decoding error
#[derive(thiserror::Error, Debug, Clone)]
pub enum MessageDecodeError {
/// More data was expected but none is available
#[error("eof unexpected")]
UnexpectedEof,
/// A received string could not be decoded as UTF8
#[error("invalid utf8 string")]
Utf8Error(#[from] std::str::Utf8Error),
}
pub(crate) fn encode_vlq_int(output: &mut Vec<u8>, v: u32) {
let sv = v as i32;
if !(-(1 << 26)..(3 << 26)).contains(&sv) {
output.push(((sv >> 28) & 0x7F) as u8 | 0x80);
}
if !(-(1 << 19)..(3 << 19)).contains(&sv) {
output.push(((sv >> 21) & 0x7F) as u8 | 0x80);
}
if !(-(1 << 12)..(3 << 12)).contains(&sv) {
output.push(((sv >> 14) & 0x7F) as u8 | 0x80);
}
if !(-(1 << 5)..(3 << 5)).contains(&sv) {
output.push(((sv >> 7) & 0x7F) as u8 | 0x80);
}
output.push((sv & 0x7F) as u8);
}
pub(crate) fn next_byte(data: &mut &[u8]) -> Result<u8, MessageDecodeError> {
if data.is_empty() {
Err(MessageDecodeError::UnexpectedEof)
} else {
let v = data[0];
*data = &data[1..];
Ok(v)
}
}
pub(crate) fn parse_vlq_int(data: &mut &[u8]) -> Result<u32, MessageDecodeError> {
let mut c = next_byte(data)? as u32;
let mut v = c & 0x7F;
if (c & 0x60) == 0x60 {
v |= (-0x20i32) as u32;
}
while c & 0x80 != 0 {
c = next_byte(data)? as u32;
v = (v << 7) | (c & 0x7F);
}
Ok(v)
}
pub trait Readable<'de>: Sized {
fn read(data: &mut &'de [u8]) -> Result<Self, MessageDecodeError>;
fn skip(data: &mut &[u8]) -> Result<(), MessageDecodeError>;
}
pub trait Writable: Sized {
fn write(&self, output: &mut Vec<u8>);
}
pub trait Borrowable: Sized {
type Borrowed<'a>
where
Self: 'a;
fn from_borrowed(src: Self::Borrowed<'_>) -> Self;
}
pub trait ToFieldType: Sized {
fn as_field_type() -> FieldType;
}
macro_rules! int_readwrite {
( $type:tt, $field_type:expr ) => {
impl Readable<'_> for $type {
fn read(data: &mut &[u8]) -> Result<Self, MessageDecodeError> {
parse_vlq_int(data).map(|v| v as $type)
}
fn skip(data: &mut &[u8]) -> Result<(), MessageDecodeError> {
parse_vlq_int(data).map(|_| ())
}
}
impl Writable for $type {
fn write(&self, output: &mut Vec<u8>) {
encode_vlq_int(output, *self as u32)
}
}
impl Borrowable for $type {
type Borrowed<'a> = Self;
fn from_borrowed(src: Self::Borrowed<'_>) -> Self {
src
}
}
impl ToFieldType for $type {
fn as_field_type() -> FieldType {
$field_type
}
}
};
}
int_readwrite!(u32, FieldType::U32);
int_readwrite!(i32, FieldType::I32);
int_readwrite!(u16, FieldType::U16);
int_readwrite!(i16, FieldType::I16);
int_readwrite!(u8, FieldType::U8);
impl Readable<'_> for bool {
fn read(data: &mut &[u8]) -> Result<Self, MessageDecodeError> {
parse_vlq_int(data).map(|v| v != 0)
}
fn skip(data: &mut &[u8]) -> Result<(), MessageDecodeError> {
parse_vlq_int(data).map(|_| ())
}
}
impl Writable for bool {
fn write(&self, output: &mut Vec<u8>) {
encode_vlq_int(output, u32::from(*self))
}
}
impl Borrowable for bool {
type Borrowed<'a> = Self;
fn from_borrowed(src: Self::Borrowed<'_>) -> Self {
src
}
}
impl ToFieldType for bool {
fn as_field_type() -> FieldType {
FieldType::U8
}
}
impl<'de> Readable<'de> for &'de [u8] {
fn read(data: &mut &'de [u8]) -> Result<&'de [u8], MessageDecodeError> {
let len = parse_vlq_int(data)? as usize;
if data.len() < len {
Err(MessageDecodeError::UnexpectedEof)
} else {
let ret = &data[..len];
*data = &data[len..];
Ok(ret)
}
}
fn skip(data: &mut &[u8]) -> Result<(), MessageDecodeError> {
let len = parse_vlq_int(data)? as usize;
if data.len() < len {
Err(MessageDecodeError::UnexpectedEof)
} else {
*data = &data[len..];
Ok(())
}
}
}
impl Writable for &[u8] {
fn write(&self, output: &mut Vec<u8>) {
encode_vlq_int(output, self.len() as u32);
output.extend_from_slice(self);
}
}
impl Borrowable for Vec<u8> {
type Borrowed<'a> = &'a [u8];
fn from_borrowed(src: Self::Borrowed<'_>) -> Self {
src.into()
}
}
impl ToFieldType for Vec<u8> {
fn as_field_type() -> FieldType {
FieldType::ByteArray
}
}
impl<'de> Readable<'de> for &'de str {
fn read(data: &mut &'de [u8]) -> Result<&'de str, MessageDecodeError> {
let len = parse_vlq_int(data)? as usize;
if data.len() < len {
Err(MessageDecodeError::UnexpectedEof)
} else {
let ret = &data[..len];
*data = &data[len..];
Ok(std::str::from_utf8(ret)?)
}
}
fn skip(data: &mut &[u8]) -> Result<(), MessageDecodeError> {
let len = parse_vlq_int(data)? as usize;
if data.len() < len {
Err(MessageDecodeError::UnexpectedEof)
} else {
*data = &data[len..];
Ok(())
}
}
}
impl Writable for &str {
fn write(&self, output: &mut Vec<u8>) {
let bytes = self.as_bytes();
encode_vlq_int(output, bytes.len() as u32);
output.extend_from_slice(bytes);
}
}
impl Borrowable for String {
type Borrowed<'a> = &'a str;
fn from_borrowed(src: Self::Borrowed<'_>) -> Self {
src.to_string()
}
}
impl ToFieldType for String {
fn as_field_type() -> FieldType {
FieldType::String
}
}
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub enum FieldType {
U32,
I32,
U16,
I16,
U8,
String,
ByteArray,
}
impl FieldType {
pub(crate) fn skip(&self, input: &mut &[u8]) -> Result<(), MessageDecodeError> {
match self {
Self::U32 => <u32 as Readable>::skip(input),
Self::I32 => <i32 as Readable>::skip(input),
Self::U16 => <u16 as Readable>::skip(input),
Self::I16 => <i16 as Readable>::skip(input),
Self::U8 => <u8 as Readable>::skip(input),
Self::String => <&str as Readable>::skip(input),
Self::ByteArray => <&[u8] as Readable>::skip(input),
}
}
pub(crate) fn read(&self, input: &mut &[u8]) -> Result<FieldValue, MessageDecodeError> {
Ok(match self {
Self::U32 => FieldValue::U32(<u32 as Readable>::read(input)?),
Self::I32 => FieldValue::I32(<i32 as Readable>::read(input)?),
Self::U16 => FieldValue::U16(<u16 as Readable>::read(input)?),
Self::I16 => FieldValue::I16(<i16 as Readable>::read(input)?),
Self::U8 => FieldValue::U8(<u8 as Readable>::read(input)?),
Self::String => FieldValue::String(<&str as Readable>::read(input)?.into()),
Self::ByteArray => FieldValue::ByteArray(<&[u8] as Readable>::read(input)?.into()),
})
}
pub(crate) fn from_msg(s: &str) -> Result<Self, MessageSkipperError> {
match s {
"%u" => Ok(Self::U32),
"%i" => Ok(Self::I32),
"%hu" => Ok(Self::U16),
"%hi" => Ok(Self::I16),
"%c" => Ok(Self::U8),
"%s" => Ok(Self::String),
"%*s" => Ok(Self::ByteArray),
"%.*s" => Ok(Self::ByteArray),
s => Err(MessageSkipperError::InvalidFormatFieldType(s.to_string())),
}
}
pub(crate) fn from_format(s: &str) -> Result<(Self, &str), MessageSkipperError> {
if let Some(rest) = s.strip_prefix("%u") {
Ok((Self::U32, rest))
} else if let Some(rest) = s.strip_prefix("%i") {
Ok((Self::I32, rest))
} else if let Some(rest) = s.strip_prefix("%hu") {
Ok((Self::U16, rest))
} else if let Some(rest) = s.strip_prefix("%hi") {
Ok((Self::I16, rest))
} else if let Some(rest) = s.strip_prefix("%c") {
Ok((Self::U8, rest))
} else if let Some(rest) = s.strip_prefix("%.*s") {
Ok((Self::ByteArray, rest))
} else if let Some(rest) = s.strip_prefix("%*s") {
Ok((Self::String, rest))
} else {
Err(MessageSkipperError::InvalidFormatFieldType(s.to_string()))
}
}
}
#[derive(Debug)]
pub enum FieldValue {
U32(u32),
I32(i32),
U16(u16),
I16(i16),
U8(u8),
String(String),
ByteArray(Vec<u8>),
}
impl Display for FieldValue {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
Self::U32(v) => write!(f, "{}", v),
Self::I32(v) => write!(f, "{}", v),
Self::U16(v) => write!(f, "{}", v),
Self::I16(v) => write!(f, "{}", v),
Self::U8(v) => write!(f, "{}", v),
Self::String(v) => write!(f, "{}", v),
Self::ByteArray(v) => write!(f, "{:?}", v),
}
}
}
|
