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//! Serialize a Rust data structure to CBOR data.
#[cfg(feature = "alloc")]
use alloc::vec::Vec;
#[cfg(feature = "std")]
pub use crate::write::IoWrite;
pub use crate::write::{SliceWrite, Write};
use crate::error::{Error, Result};
use half::f16;
use serde::ser::{self, Serialize};
#[cfg(feature = "std")]
use std::io;
use crate::tags::{get_tag, CBOR_NEWTYPE_NAME};
/// Serializes a value to a vector.
#[cfg(any(feature = "std", feature = "alloc"))]
pub fn to_vec<T>(value: &T) -> Result<Vec<u8>>
where
T: ser::Serialize,
{
let mut vec = Vec::new();
value.serialize(&mut Serializer::new(&mut vec))?;
Ok(vec)
}
/// Serializes a value to a vector in packed format.
#[cfg(feature = "std")]
pub fn to_vec_packed<T>(value: &T) -> Result<Vec<u8>>
where
T: ser::Serialize,
{
let mut vec = Vec::new();
value.serialize(&mut Serializer::new(&mut IoWrite::new(&mut vec)).packed_format())?;
Ok(vec)
}
/// Serializes a value to a writer.
#[cfg(feature = "std")]
pub fn to_writer<W, T>(writer: W, value: &T) -> Result<()>
where
W: io::Write,
T: ser::Serialize,
{
value.serialize(&mut Serializer::new(&mut IoWrite::new(writer)))
}
/// A structure for serializing Rust values to CBOR.
#[derive(Debug)]
pub struct Serializer<W> {
writer: W,
packed: bool,
enum_as_map: bool,
}
impl<W> Serializer<W>
where
W: Write,
{
/// Creates a new CBOR serializer.
///
/// `to_vec` and `to_writer` should normally be used instead of this method.
#[inline]
pub fn new(writer: W) -> Self {
Serializer {
writer,
packed: false,
enum_as_map: true,
}
}
/// Choose concise/packed format for serializer.
///
/// In the packed format enum variant names and field names
/// are replaced with numeric indizes to conserve space.
pub fn packed_format(mut self) -> Self {
self.packed = true;
self
}
/// Enable old enum format used by `serde_cbor` versions <= v0.9.
///
/// The `legacy_enums` option determines how enums are encoded.
///
/// This makes no difference when encoding and decoding enums using
/// this crate, but it shows up when decoding to a `Value` or decoding
/// in other languages.
///
/// # Examples
///
/// Given the following enum
///
/// ```rust
/// enum Enum {
/// Unit,
/// NewType(i32),
/// Tuple(String, bool),
/// Struct{ x: i32, y: i32 },
/// }
/// ```
/// we will give the `Value` with the same encoding for each case using
/// JSON notation.
///
/// ## Default encodings
///
/// * `Enum::Unit` encodes as `"Unit"`
/// * `Enum::NewType(10)` encodes as `{"NewType": 10}`
/// * `Enum::Tuple("x", true)` encodes as `{"Tuple": ["x", true]}`
///
/// ## Legacy encodings
///
/// * `Enum::Unit` encodes as `"Unit"`
/// * `Enum::NewType(10)` encodes as `["NewType", 10]`
/// * `Enum::Tuple("x", true)` encodes as `["Tuple", "x", true]`
/// * `Enum::Struct{ x: 5, y: -5 }` encodes as `["Struct", {"x": 5, "y": -5}]`
pub fn legacy_enums(mut self) -> Self {
self.enum_as_map = false;
self
}
/// Writes a CBOR self-describe tag to the stream.
///
/// Tagging allows a decoder to distinguish different file formats based on their content
/// without further information.
#[inline]
pub fn self_describe(&mut self) -> Result<()> {
let mut buf = [6 << 5 | 25, 0, 0];
(&mut buf[1..]).copy_from_slice(&55799u16.to_be_bytes());
self.writer.write_all(&buf).map_err(|e| e.into())
}
/// Unwrap the `Writer` from the `Serializer`.
#[inline]
pub fn into_inner(self) -> W {
self.writer
}
#[inline]
fn write_u8(&mut self, major: u8, value: u8) -> Result<()> {
if value <= 0x17 {
self.writer.write_all(&[major << 5 | value])
} else {
let buf = [major << 5 | 24, value];
self.writer.write_all(&buf)
}
.map_err(|e| e.into())
}
#[inline]
fn write_u16(&mut self, major: u8, value: u16) -> Result<()> {
if value <= u16::from(u8::max_value()) {
self.write_u8(major, value as u8)
} else {
let mut buf = [major << 5 | 25, 0, 0];
(&mut buf[1..]).copy_from_slice(&value.to_be_bytes());
self.writer.write_all(&buf).map_err(|e| e.into())
}
}
#[inline]
fn write_u32(&mut self, major: u8, value: u32) -> Result<()> {
if value <= u32::from(u16::max_value()) {
self.write_u16(major, value as u16)
} else {
let mut buf = [major << 5 | 26, 0, 0, 0, 0];
(&mut buf[1..]).copy_from_slice(&value.to_be_bytes());
self.writer.write_all(&buf).map_err(|e| e.into())
}
}
#[inline]
fn write_u64(&mut self, major: u8, value: u64) -> Result<()> {
if value <= u64::from(u32::max_value()) {
self.write_u32(major, value as u32)
} else {
let mut buf = [major << 5 | 27, 0, 0, 0, 0, 0, 0, 0, 0];
(&mut buf[1..]).copy_from_slice(&value.to_be_bytes());
self.writer.write_all(&buf).map_err(|e| e.into())
}
}
#[inline]
fn serialize_collection<'a>(
&'a mut self,
major: u8,
len: Option<usize>,
) -> Result<CollectionSerializer<'a, W>> {
let needs_eof = match len {
Some(len) => {
self.write_u64(major, len as u64)?;
false
}
None => {
self.writer
.write_all(&[major << 5 | 31])
.map_err(|e| e.into())?;
true
}
};
Ok(CollectionSerializer {
ser: self,
needs_eof,
})
}
}
impl<'a, W> ser::Serializer for &'a mut Serializer<W>
where
W: Write,
{
type Ok = ();
type Error = Error;
type SerializeSeq = CollectionSerializer<'a, W>;
type SerializeTuple = &'a mut Serializer<W>;
type SerializeTupleStruct = &'a mut Serializer<W>;
type SerializeTupleVariant = &'a mut Serializer<W>;
type SerializeMap = CollectionSerializer<'a, W>;
type SerializeStruct = StructSerializer<'a, W>;
type SerializeStructVariant = StructSerializer<'a, W>;
#[inline]
fn serialize_bool(self, value: bool) -> Result<()> {
let value = if value { 0xf5 } else { 0xf4 };
self.writer.write_all(&[value]).map_err(|e| e.into())
}
#[inline]
fn serialize_i8(self, value: i8) -> Result<()> {
if value < 0 {
self.write_u8(1, -(value + 1) as u8)
} else {
self.write_u8(0, value as u8)
}
}
#[inline]
fn serialize_i16(self, value: i16) -> Result<()> {
if value < 0 {
self.write_u16(1, -(value + 1) as u16)
} else {
self.write_u16(0, value as u16)
}
}
#[inline]
fn serialize_i32(self, value: i32) -> Result<()> {
if value < 0 {
self.write_u32(1, -(value + 1) as u32)
} else {
self.write_u32(0, value as u32)
}
}
#[inline]
fn serialize_i64(self, value: i64) -> Result<()> {
if value < 0 {
self.write_u64(1, -(value + 1) as u64)
} else {
self.write_u64(0, value as u64)
}
}
#[inline]
fn serialize_i128(self, value: i128) -> Result<()> {
if value < 0 {
if -(value + 1) > i128::from(u64::max_value()) {
return Err(Error::message("The number can't be stored in CBOR"));
}
self.write_u64(1, -(value + 1) as u64)
} else {
if value > i128::from(u64::max_value()) {
return Err(Error::message("The number can't be stored in CBOR"));
}
self.write_u64(0, value as u64)
}
}
#[inline]
fn serialize_u8(self, value: u8) -> Result<()> {
self.write_u8(0, value)
}
#[inline]
fn serialize_u16(self, value: u16) -> Result<()> {
self.write_u16(0, value)
}
#[inline]
fn serialize_u32(self, value: u32) -> Result<()> {
self.write_u32(0, value)
}
#[inline]
fn serialize_u64(self, value: u64) -> Result<()> {
self.write_u64(0, value)
}
#[inline]
fn serialize_u128(self, value: u128) -> Result<()> {
if value > u128::from(u64::max_value()) {
return Err(Error::message("The number can't be stored in CBOR"));
}
self.write_u64(0, value as u64)
}
#[inline]
#[allow(clippy::float_cmp)]
fn serialize_f32(self, value: f32) -> Result<()> {
if value.is_infinite() {
if value.is_sign_positive() {
self.writer.write_all(&[0xf9, 0x7c, 0x00])
} else {
self.writer.write_all(&[0xf9, 0xfc, 0x00])
}
} else if value.is_nan() {
self.writer.write_all(&[0xf9, 0x7e, 0x00])
} else if f32::from(f16::from_f32(value)) == value {
let mut buf = [0xf9, 0, 0];
(&mut buf[1..]).copy_from_slice(&f16::from_f32(value).to_bits().to_be_bytes());
self.writer.write_all(&buf)
} else {
let mut buf = [0xfa, 0, 0, 0, 0];
(&mut buf[1..]).copy_from_slice(&value.to_bits().to_be_bytes());
self.writer.write_all(&buf)
}
.map_err(|e| e.into())
}
#[inline]
#[allow(clippy::float_cmp)]
fn serialize_f64(self, value: f64) -> Result<()> {
if !value.is_finite() || f64::from(value as f32) == value {
self.serialize_f32(value as f32)
} else {
let mut buf = [0xfb, 0, 0, 0, 0, 0, 0, 0, 0];
(&mut buf[1..]).copy_from_slice(&value.to_bits().to_be_bytes());
self.writer.write_all(&buf).map_err(|e| e.into())
}
}
#[inline]
fn serialize_char(self, value: char) -> Result<()> {
// A char encoded as UTF-8 takes 4 bytes at most.
let mut buf = [0; 4];
self.serialize_str(value.encode_utf8(&mut buf))
}
#[inline]
fn serialize_str(self, value: &str) -> Result<()> {
self.write_u64(3, value.len() as u64)?;
self.writer
.write_all(value.as_bytes())
.map_err(|e| e.into())
}
#[inline]
fn serialize_bytes(self, value: &[u8]) -> Result<()> {
self.write_u64(2, value.len() as u64)?;
self.writer.write_all(value).map_err(|e| e.into())
}
#[inline]
fn serialize_unit(self) -> Result<()> {
self.serialize_none()
}
#[inline]
fn serialize_some<T>(self, value: &T) -> Result<()>
where
T: ?Sized + ser::Serialize,
{
value.serialize(self)
}
#[inline]
fn serialize_none(self) -> Result<()> {
self.writer.write_all(&[0xf6]).map_err(|e| e.into())
}
#[inline]
fn serialize_unit_struct(self, _name: &'static str) -> Result<()> {
self.serialize_unit()
}
#[inline]
fn serialize_unit_variant(
self,
_name: &'static str,
variant_index: u32,
variant: &'static str,
) -> Result<()> {
if self.packed {
self.serialize_u32(variant_index)
} else {
self.serialize_str(variant)
}
}
#[inline]
fn serialize_newtype_struct<T>(self, name: &'static str, value: &T) -> Result<()>
where
T: ?Sized + ser::Serialize,
{
if name == CBOR_NEWTYPE_NAME {
for tag in get_tag().into_iter() {
self.write_u64(6, tag)?;
}
}
value.serialize(self)
}
#[inline]
fn serialize_newtype_variant<T>(
self,
name: &'static str,
variant_index: u32,
variant: &'static str,
value: &T,
) -> Result<()>
where
T: ?Sized + ser::Serialize,
{
if self.enum_as_map {
self.write_u64(5, 1u64)?;
variant.serialize(&mut *self)?;
} else {
self.writer.write_all(&[4 << 5 | 2]).map_err(|e| e.into())?;
self.serialize_unit_variant(name, variant_index, variant)?;
}
value.serialize(self)
}
#[inline]
fn serialize_seq(self, len: Option<usize>) -> Result<CollectionSerializer<'a, W>> {
self.serialize_collection(4, len)
}
#[inline]
fn serialize_tuple(self, len: usize) -> Result<&'a mut Serializer<W>> {
self.write_u64(4, len as u64)?;
Ok(self)
}
#[inline]
fn serialize_tuple_struct(
self,
_name: &'static str,
len: usize,
) -> Result<&'a mut Serializer<W>> {
self.serialize_tuple(len)
}
#[inline]
fn serialize_tuple_variant(
self,
name: &'static str,
variant_index: u32,
variant: &'static str,
len: usize,
) -> Result<&'a mut Serializer<W>> {
if self.enum_as_map {
self.write_u64(5, 1u64)?;
variant.serialize(&mut *self)?;
self.serialize_tuple(len)
} else {
self.write_u64(4, (len + 1) as u64)?;
self.serialize_unit_variant(name, variant_index, variant)?;
Ok(self)
}
}
#[inline]
fn serialize_map(self, len: Option<usize>) -> Result<CollectionSerializer<'a, W>> {
self.serialize_collection(5, len)
}
#[cfg(not(feature = "std"))]
fn collect_str<T: ?Sized>(self, value: &T) -> Result<()>
where
T: core::fmt::Display,
{
use crate::write::FmtWrite;
use core::fmt::Write;
let mut w = FmtWrite::new(&mut self.writer);
write!(w, "{}", value)?;
Ok(())
}
#[inline]
fn serialize_struct(self, _name: &'static str, len: usize) -> Result<StructSerializer<'a, W>> {
self.write_u64(5, len as u64)?;
Ok(StructSerializer { ser: self, idx: 0 })
}
#[inline]
fn serialize_struct_variant(
self,
name: &'static str,
variant_index: u32,
variant: &'static str,
len: usize,
) -> Result<StructSerializer<'a, W>> {
if self.enum_as_map {
self.write_u64(5, 1u64)?;
} else {
self.writer.write_all(&[4 << 5 | 2]).map_err(|e| e.into())?;
}
self.serialize_unit_variant(name, variant_index, variant)?;
self.serialize_struct(name, len)
}
#[inline]
fn is_human_readable(&self) -> bool {
false
}
}
impl<'a, W> ser::SerializeTuple for &'a mut Serializer<W>
where
W: Write,
{
type Ok = ();
type Error = Error;
#[inline]
fn serialize_element<T>(&mut self, value: &T) -> Result<()>
where
T: ?Sized + ser::Serialize,
{
value.serialize(&mut **self)
}
#[inline]
fn end(self) -> Result<()> {
Ok(())
}
}
impl<'a, W> ser::SerializeTupleStruct for &'a mut Serializer<W>
where
W: Write,
{
type Ok = ();
type Error = Error;
#[inline]
fn serialize_field<T>(&mut self, value: &T) -> Result<()>
where
T: ?Sized + ser::Serialize,
{
value.serialize(&mut **self)
}
#[inline]
fn end(self) -> Result<()> {
Ok(())
}
}
impl<'a, W> ser::SerializeTupleVariant for &'a mut Serializer<W>
where
W: Write,
{
type Ok = ();
type Error = Error;
#[inline]
fn serialize_field<T>(&mut self, value: &T) -> Result<()>
where
T: ?Sized + ser::Serialize,
{
value.serialize(&mut **self)
}
#[inline]
fn end(self) -> Result<()> {
Ok(())
}
}
#[doc(hidden)]
pub struct StructSerializer<'a, W> {
ser: &'a mut Serializer<W>,
idx: u32,
}
impl<'a, W> StructSerializer<'a, W>
where
W: Write,
{
#[inline]
fn serialize_field_inner<T>(&mut self, key: &'static str, value: &T) -> Result<()>
where
T: ?Sized + ser::Serialize,
{
if self.ser.packed {
self.idx.serialize(&mut *self.ser)?;
} else {
key.serialize(&mut *self.ser)?;
}
value.serialize(&mut *self.ser)?;
self.idx += 1;
Ok(())
}
#[inline]
fn skip_field_inner(&mut self, _: &'static str) -> Result<()> {
self.idx += 1;
Ok(())
}
#[inline]
fn end_inner(self) -> Result<()> {
Ok(())
}
}
impl<'a, W> ser::SerializeStruct for StructSerializer<'a, W>
where
W: Write,
{
type Ok = ();
type Error = Error;
#[inline]
fn serialize_field<T>(&mut self, key: &'static str, value: &T) -> Result<()>
where
T: ?Sized + ser::Serialize,
{
self.serialize_field_inner(key, value)
}
#[inline]
fn skip_field(&mut self, key: &'static str) -> Result<()> {
self.skip_field_inner(key)
}
#[inline]
fn end(self) -> Result<()> {
self.end_inner()
}
}
impl<'a, W> ser::SerializeStructVariant for StructSerializer<'a, W>
where
W: Write,
{
type Ok = ();
type Error = Error;
#[inline]
fn serialize_field<T>(&mut self, key: &'static str, value: &T) -> Result<()>
where
T: ?Sized + ser::Serialize,
{
self.serialize_field_inner(key, value)
}
#[inline]
fn skip_field(&mut self, key: &'static str) -> Result<()> {
self.skip_field_inner(key)
}
#[inline]
fn end(self) -> Result<()> {
self.end_inner()
}
}
#[doc(hidden)]
pub struct CollectionSerializer<'a, W> {
ser: &'a mut Serializer<W>,
needs_eof: bool,
}
impl<'a, W> CollectionSerializer<'a, W>
where
W: Write,
{
#[inline]
fn end_inner(self) -> Result<()> {
if self.needs_eof {
self.ser.writer.write_all(&[0xff]).map_err(|e| e.into())
} else {
Ok(())
}
}
}
impl<'a, W> ser::SerializeSeq for CollectionSerializer<'a, W>
where
W: Write,
{
type Ok = ();
type Error = Error;
#[inline]
fn serialize_element<T>(&mut self, value: &T) -> Result<()>
where
T: ?Sized + ser::Serialize,
{
value.serialize(&mut *self.ser)
}
#[inline]
fn end(self) -> Result<()> {
self.end_inner()
}
}
impl<'a, W> ser::SerializeMap for CollectionSerializer<'a, W>
where
W: Write,
{
type Ok = ();
type Error = Error;
#[inline]
fn serialize_key<T>(&mut self, key: &T) -> Result<()>
where
T: ?Sized + ser::Serialize,
{
key.serialize(&mut *self.ser)
}
#[inline]
fn serialize_value<T>(&mut self, value: &T) -> Result<()>
where
T: ?Sized + ser::Serialize,
{
value.serialize(&mut *self.ser)
}
#[inline]
fn end(self) -> Result<()> {
self.end_inner()
}
}