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use crate::*;
/// Describes type of Value.
#[derive(
Clone,
Debug,
Default,
Hash,
PartialEq,
Eq,
PartialOrd,
Ord,
serde::Serialize,
serde::Deserialize,
)]
pub enum DataType {
#[default]
/// Todo
Empty,
/// e.g. `( string, string, int )`
Tuple(LVec<DataType>),
/// e.g. `struct{ name: string, email: string, created: date }`
Struct(LVec<(LString, DataType)>),
/// e.g. `enum{ leaf: int, node: [int] }`
Enum(LVec<(LString, DataType)>),
/// e.g. `string`
String,
/// e.g. `binary`
Binary,
/// e.g. `int`
Int,
// Array of values.
// Array(usize, LBox<DataType>),
/// List of values.
List(LBox<DataType>),
// e.g. `[string->int]`
// Map(LBox<DataType>, LBox<DataType>),
/// List of 64-bit integers.
IList,
DataType,
TabInfo,
}
impl DataType {
/// Encode value (which must match DataType) as bytes. DataType will later be used to decode the bytes.
pub fn value_to_bytes(&self, val: &Value) -> LVec<u8> {
let mut w = LVec::new();
self.value_to_writer(val, &mut w);
w
}
/// Encode value (which must match DataType) as bytes. DataType will later be used to decode the bytes.
pub fn value_to_writer<W: std::io::Write>(&self, val: &Value, w: &mut W) {
match self {
DataType::Tuple(types) => {
let list = val.list();
for (i, t) in types.into_iter().enumerate() {
t.value_to_writer(&list[i], w);
}
}
DataType::Struct(fields) => {
let list = val.list();
for (i, f) in fields.into_iter().enumerate() {
f.1.value_to_writer(&list[i], w);
}
}
DataType::Enum(variants) => {
let (tag, val) = val.en();
self.write_usize(*tag, w);
variants[*tag].1.value_to_writer(val, w);
}
DataType::String => {
let s = val.string();
self.write_usize(s.len(), w);
let _ = w.write(s.as_bytes());
}
DataType::Binary => {
let b = val.binary();
self.write_usize(b.len(), w);
let _ = w.write(b);
}
DataType::Int => {
let i = val.int();
let _ = w.write(&i.to_le_bytes());
}
DataType::Empty => {}
DataType::List(t) => {
let list = val.list();
self.write_usize(list.len(), w);
for v in list {
t.value_to_writer(v, w);
}
}
DataType::IList => {
let list = val.ilist();
self.write_usize(list.len(), w);
for i in list {
self.write_int(*i, w);
}
}
DataType::DataType => {
let val = val.datatype().to_bytes();
self.write_usize(val.len(), w);
let _ = w.write(&val);
}
DataType::TabInfo => {
let val = val.tabinfo().to_bytes();
self.write_usize(val.len(), w);
let _ = w.write(&val);
}
}
}
/// Decode bytes of this DataType. ix is advanced according to the bytes read from buf. Returns decoded Value.
pub fn bytes_to_value(&self, buf: &[u8]) -> Value {
let mut ix = 0;
self.to_value(buf, &mut ix)
}
/// Decode bytes of this DataType. ix is advanced according to the bytes read from buf. Returns decoded Value.
fn to_value(&self, buf: &[u8], ix: &mut usize) -> Value {
match self {
DataType::Tuple(types) => {
let mut list = LVec::with_capacity(types.len());
for t in types {
let v = t.to_value(buf, ix);
list.push(v);
}
Value::List(list)
}
DataType::Struct(fields) => {
let mut list = LVec::with_capacity(fields.len());
for f in fields {
let v = f.1.to_value(buf, ix);
list.push(v);
}
Value::List(list)
}
DataType::Enum(variants) => {
let tag = self.read_usize(buf, ix);
let val = variants[tag].1.to_value(buf, ix);
Value::Enum(tag, LBox::new(val))
}
DataType::String => {
let len = self.read_usize(buf, ix);
let s = &buf[*ix..*ix + len];
*ix += len;
let s = str::from_utf8(s).unwrap();
let s = LString::from(s);
Value::String(s)
}
DataType::Binary => {
let len = self.read_usize(buf, ix);
let b = &buf[*ix..*ix + len];
*ix += len;
let b = LVec::<u8>::from(b);
Value::Binary(b)
}
DataType::Int => {
let i = self.read_int(buf, ix);
Value::Int(i)
}
DataType::Empty => Value::Empty,
DataType::List(t) => {
let len = self.read_usize(buf, ix);
let mut list = LVec::with_capacity(len);
for _i in 0..len {
let v = t.to_value(buf, ix);
list.push(v);
}
Value::List(list)
}
DataType::IList => {
let len = self.read_usize(buf, ix);
let mut list = LVec::with_capacity(len);
for _i in 0..len {
let i = self.read_int(buf, ix);
list.push(i);
}
Value::IList(list)
}
DataType::DataType => {
let len = self.read_usize(buf, ix);
let b = &buf[*ix..*ix + len];
*ix += len;
Value::DataType(DataType::from_bytes(b))
}
DataType::TabInfo => {
let len = self.read_usize(buf, ix);
let b = &buf[*ix..*ix + len];
*ix += len;
Value::TabInfo(TabInfo::from_bytes(b))
}
}
}
fn write_usize<W: std::io::Write>(&self, mut val: usize, w: &mut W) {
/*
// Use a variable length encoding to be efficient for small sizes.
let val = val as u64;
let _ = w.write(&val.to_le_bytes());
*/
let mut buf = [0u8; 10]; // 7 * 10 = 70 bits, which is more than 64 bits.
let mut ix = 0;
loop {
let b = (val % 128) as u8;
val /= 128;
if val == 0 {
buf[ix] = b;
ix += 1;
break;
} else {
buf[ix] = b + 128;
ix += 1;
}
}
let _ = w.write(&buf[0..ix]);
}
fn read_usize(&self, buf: &[u8], ix: &mut usize) -> usize {
// Use a variable length encoding to be efficient for small sizes.
// let x = u64::from_le_bytes(buf[*ix..*ix + 8].try_into().unwrap());
// *ix += 8;
// x as usize
// Last byte has 0 in top bit.
let mut x: usize = 0;
let mut i = 0;
loop {
let b = buf[*ix];
*ix += 1;
let f = b & 128;
x += ((b & 127) as usize) << i;
if f == 0 {
break;
}
i += 7;
}
x
}
fn write_int<W: std::io::Write>(&self, val: i64, w: &mut W) {
// Could use a variable length encoding to be efficient for small ints.
let _ = w.write(&val.to_le_bytes());
}
fn read_int(&self, buf: &[u8], ix: &mut usize) -> i64 {
// Could use a variable length encoding to be efficient for small ints.
let x = i64::from_le_bytes(buf[*ix..*ix + 8].try_into().unwrap());
*ix += 8;
x
}
pub fn to_bytes(&self) -> Vec<u8> {
postcard::to_stdvec(self).unwrap()
}
pub fn from_bytes(b: &[u8]) -> Self {
postcard::from_bytes(b).unwrap()
}
}