use std::collections::BTreeMap;
use crate::error::{AppError, Result};
#[derive(Debug, Clone, PartialEq)]
pub enum MsgValue {
Nil,
Bool(bool),
Int(i64),
UInt(u64),
String(String),
Array(Vec<MsgValue>),
Map(BTreeMap<String, MsgValue>),
}
impl MsgValue {
pub fn get(&self, key: &str) -> Option<&MsgValue> {
match self {
MsgValue::Map(map) => map.get(key),
_ => None,
}
}
pub fn as_str(&self) -> Option<&str> {
match self {
MsgValue::String(value) => Some(value.as_str()),
_ => None,
}
}
pub fn as_array(&self) -> Option<&[MsgValue]> {
match self {
MsgValue::Array(values) => Some(values.as_slice()),
_ => None,
}
}
pub fn as_map(&self) -> Option<&BTreeMap<String, MsgValue>> {
match self {
MsgValue::Map(map) => Some(map),
_ => None,
}
}
pub fn as_u64(&self) -> Option<u64> {
match self {
MsgValue::UInt(value) => Some(*value),
MsgValue::Int(value) if *value >= 0 => Some(*value as u64),
_ => None,
}
}
}
pub fn encode(value: &MsgValue) -> Vec<u8> {
let mut buffer = Vec::new();
encode_value(value, &mut buffer);
buffer
}
pub fn decode(bytes: &[u8]) -> Result<MsgValue> {
let (value, consumed) = decode_value(bytes, 0)?;
if consumed != bytes.len() {
return Err(AppError::Msgpack(
"trailing bytes in msgpack payload".to_string(),
));
}
Ok(value)
}
fn encode_value(value: &MsgValue, buffer: &mut Vec<u8>) {
match value {
MsgValue::Nil => buffer.push(0xc0),
MsgValue::Bool(false) => buffer.push(0xc2),
MsgValue::Bool(true) => buffer.push(0xc3),
MsgValue::Int(value) => encode_int(*value, buffer),
MsgValue::UInt(value) => encode_uint(*value, buffer),
MsgValue::String(value) => encode_str(value, buffer),
MsgValue::Array(values) => encode_array(values, buffer),
MsgValue::Map(map) => encode_map(map, buffer),
}
}
fn encode_uint(value: u64, buffer: &mut Vec<u8>) {
match value {
0..=127 => buffer.push(value as u8),
128..=255 => {
buffer.push(0xcc);
buffer.push(value as u8);
}
256..=65_535 => {
buffer.push(0xcd);
buffer.extend_from_slice(&(value as u16).to_be_bytes());
}
65_536..=4_294_967_295 => {
buffer.push(0xce);
buffer.extend_from_slice(&(value as u32).to_be_bytes());
}
_ => {
buffer.push(0xcf);
buffer.extend_from_slice(&value.to_be_bytes());
}
}
}
fn encode_int(value: i64, buffer: &mut Vec<u8>) {
if (-32..=127).contains(&value) {
if value >= 0 {
buffer.push(value as u8);
} else {
buffer.push((value as i8) as u8);
}
return;
}
if (-128..=-33).contains(&value) {
buffer.push(0xd0);
buffer.push(value as i8 as u8);
} else if (-32_768..=-129).contains(&value) {
buffer.push(0xd1);
buffer.extend_from_slice(&(value as i16).to_be_bytes());
} else if (-2_147_483_648..=-32_769).contains(&value) {
buffer.push(0xd2);
buffer.extend_from_slice(&(value as i32).to_be_bytes());
} else {
buffer.push(0xd3);
buffer.extend_from_slice(&value.to_be_bytes());
}
}
fn encode_str(value: &str, buffer: &mut Vec<u8>) {
let bytes = value.as_bytes();
let len = bytes.len();
if len <= 31 {
buffer.push(0xa0 | (len as u8));
} else if len <= 255 {
buffer.push(0xd9);
buffer.push(len as u8);
} else if len <= 65_535 {
buffer.push(0xda);
buffer.extend_from_slice(&(len as u16).to_be_bytes());
} else {
buffer.push(0xdb);
buffer.extend_from_slice(&(len as u32).to_be_bytes());
}
buffer.extend_from_slice(bytes);
}
fn encode_array(values: &[MsgValue], buffer: &mut Vec<u8>) {
let len = values.len();
if len <= 15 {
buffer.push(0x90 | (len as u8));
} else if len <= 65_535 {
buffer.push(0xdc);
buffer.extend_from_slice(&(len as u16).to_be_bytes());
} else {
buffer.push(0xdd);
buffer.extend_from_slice(&(len as u32).to_be_bytes());
}
for value in values {
encode_value(value, buffer);
}
}
fn encode_map(map: &BTreeMap<String, MsgValue>, buffer: &mut Vec<u8>) {
let len = map.len();
if len <= 15 {
buffer.push(0x80 | (len as u8));
} else if len <= 65_535 {
buffer.push(0xde);
buffer.extend_from_slice(&(len as u16).to_be_bytes());
} else {
buffer.push(0xdf);
buffer.extend_from_slice(&(len as u32).to_be_bytes());
}
for (key, value) in map {
encode_str(key, buffer);
encode_value(value, buffer);
}
}
fn decode_value(bytes: &[u8], index: usize) -> Result<(MsgValue, usize)> {
let prefix = *bytes
.get(index)
.ok_or_else(|| AppError::Msgpack("unexpected end of msgpack payload".to_string()))?;
match prefix {
0xc0 => Ok((MsgValue::Nil, index + 1)),
0xc2 => Ok((MsgValue::Bool(false), index + 1)),
0xc3 => Ok((MsgValue::Bool(true), index + 1)),
0xcc => {
let value = read_u8(bytes, index + 1)? as u64;
Ok((MsgValue::UInt(value), index + 2))
}
0xcd => {
let value = read_u16(bytes, index + 1)? as u64;
Ok((MsgValue::UInt(value), index + 3))
}
0xce => {
let value = read_u32(bytes, index + 1)? as u64;
Ok((MsgValue::UInt(value), index + 5))
}
0xcf => {
let value = read_u64(bytes, index + 1)?;
Ok((MsgValue::UInt(value), index + 9))
}
0xd0 => {
let value = read_i8(bytes, index + 1)? as i64;
Ok((MsgValue::Int(value), index + 2))
}
0xd1 => {
let value = read_i16(bytes, index + 1)? as i64;
Ok((MsgValue::Int(value), index + 3))
}
0xd2 => {
let value = read_i32(bytes, index + 1)? as i64;
Ok((MsgValue::Int(value), index + 5))
}
0xd3 => {
let value = read_i64(bytes, index + 1)?;
Ok((MsgValue::Int(value), index + 9))
}
0xd9 => {
let len = read_u8(bytes, index + 1)? as usize;
decode_str(bytes, index + 2, len)
}
0xda => {
let len = read_u16(bytes, index + 1)? as usize;
decode_str(bytes, index + 3, len)
}
0xdb => {
let len = read_u32(bytes, index + 1)? as usize;
decode_str(bytes, index + 5, len)
}
0xdc => {
let len = read_u16(bytes, index + 1)? as usize;
decode_array(bytes, index + 3, len)
}
0xdd => {
let len = read_u32(bytes, index + 1)? as usize;
decode_array(bytes, index + 5, len)
}
0xde => {
let len = read_u16(bytes, index + 1)? as usize;
decode_map(bytes, index + 3, len)
}
0xdf => {
let len = read_u32(bytes, index + 1)? as usize;
decode_map(bytes, index + 5, len)
}
0x80..=0x8f => {
let len = (prefix & 0x0f) as usize;
decode_map(bytes, index + 1, len)
}
0x90..=0x9f => {
let len = (prefix & 0x0f) as usize;
decode_array(bytes, index + 1, len)
}
0xa0..=0xbf => {
let len = (prefix & 0x1f) as usize;
decode_str(bytes, index + 1, len)
}
0xe0..=0xff => Ok((MsgValue::Int((prefix as i8) as i64), index + 1)),
0x00..=0x7f => Ok((MsgValue::UInt(prefix as u64), index + 1)),
_ => Err(AppError::Msgpack(format!(
"unsupported msgpack prefix: 0x{prefix:02x}"
))),
}
}
fn decode_str(bytes: &[u8], index: usize, len: usize) -> Result<(MsgValue, usize)> {
let end = index
.checked_add(len)
.ok_or_else(|| AppError::Msgpack("msgpack string length overflow".to_string()))?;
let slice = bytes
.get(index..end)
.ok_or_else(|| AppError::Msgpack("unexpected end of msgpack string".to_string()))?;
let value = String::from_utf8(slice.to_vec())
.map_err(|e| AppError::Msgpack(format!("invalid utf-8 string: {e}")))?;
Ok((MsgValue::String(value), end))
}
fn decode_array(bytes: &[u8], mut index: usize, len: usize) -> Result<(MsgValue, usize)> {
let mut values = Vec::with_capacity(len);
for _ in 0..len {
let (value, next) = decode_value(bytes, index)?;
values.push(value);
index = next;
}
Ok((MsgValue::Array(values), index))
}
fn decode_map(bytes: &[u8], mut index: usize, len: usize) -> Result<(MsgValue, usize)> {
let mut map = BTreeMap::new();
for _ in 0..len {
let (key_value, next_key) = decode_value(bytes, index)?;
index = next_key;
let key = key_value
.as_str()
.ok_or_else(|| AppError::Msgpack("msgpack map key was not a string".to_string()))?;
let (value, next_value) = decode_value(bytes, index)?;
index = next_value;
map.insert(key.to_string(), value);
}
Ok((MsgValue::Map(map), index))
}
fn read_u8(bytes: &[u8], index: usize) -> Result<u8> {
bytes
.get(index)
.copied()
.ok_or_else(|| AppError::Msgpack("unexpected end of msgpack payload".to_string()))
}
fn read_i8(bytes: &[u8], index: usize) -> Result<i8> {
Ok(read_u8(bytes, index)? as i8)
}
fn read_u16(bytes: &[u8], index: usize) -> Result<u16> {
let end = index + 2;
let slice = bytes
.get(index..end)
.ok_or_else(|| AppError::Msgpack("unexpected end of msgpack payload".to_string()))?;
Ok(u16::from_be_bytes([slice[0], slice[1]]))
}
fn read_i16(bytes: &[u8], index: usize) -> Result<i16> {
Ok(i16::from_be_bytes(read_u16(bytes, index)?.to_be_bytes()))
}
fn read_u32(bytes: &[u8], index: usize) -> Result<u32> {
let end = index + 4;
let slice = bytes
.get(index..end)
.ok_or_else(|| AppError::Msgpack("unexpected end of msgpack payload".to_string()))?;
Ok(u32::from_be_bytes([slice[0], slice[1], slice[2], slice[3]]))
}
fn read_i32(bytes: &[u8], index: usize) -> Result<i32> {
Ok(i32::from_be_bytes(read_u32(bytes, index)?.to_be_bytes()))
}
fn read_u64(bytes: &[u8], index: usize) -> Result<u64> {
let end = index + 8;
let slice = bytes
.get(index..end)
.ok_or_else(|| AppError::Msgpack("unexpected end of msgpack payload".to_string()))?;
Ok(u64::from_be_bytes([
slice[0], slice[1], slice[2], slice[3], slice[4], slice[5], slice[6], slice[7],
]))
}
fn read_i64(bytes: &[u8], index: usize) -> Result<i64> {
Ok(i64::from_be_bytes(read_u64(bytes, index)?.to_be_bytes()))
}