fastserial 0.1.1

//! # FastSerial
//!
//! `fastserial` is a high-performance, format-agnostic serialization framework for Rust.
//! It is an **ambitious project** designed for specific high-throughput use cases
//! by leveraging specialized code generation and SIMD-accelerated scanning.
//!
//! ## Design Goals
//!
//! - **High Performance**: Aiming for maximum throughput in JSON and Binary formats.
//! - **Zero-Copy**: Borrowed data types (like `&str` and `&[u8]`) are deserialized without allocation.
//! - **SIMD Acceleration**: First-class support for AVX2 and SSE4.2 instructions for JSON parsing.
//! - **Safety First**: While leveraging `unsafe` for SIMD, the public API remains completely safe.
//! - **Minimal Overhead**: Thin abstraction layer that compiles down to efficient machine code.
//!
//! ## Supported Formats
//!
//! | Format | Module | Description |
//! |--------|--------|-------------|
//! | JSON   | [`json`] | High-speed JSON with SIMD scanning. |
//! | Binary | [`binary`] | Compact, schema-validated binary format. |
//!
//! ## Core Traits
//!
//! There are two primary traits that power `fastserial`:
//!
//! 1.  **[`Encode`]**: Types that can be serialized into a supported format.
//! 2.  **[`Decode`]**: Types that can be deserialized from a byte buffer.
//!
//! For most users, these traits should be implemented using the `derive` macros:
//!
//! ```rust
//! use fastserial::{Encode, Decode, json};
//!
//! #[derive(Encode, Decode, Debug, PartialEq)]
//! struct User {
//!     id: u64,
//!     username: String,
//!     email: String,
//! }
//!
//! # fn main() -> Result<(), fastserial::Error> {
//! let user = User {
//!     id: 42,
//!     username: "dev_user".to_string(),
//!     email: "dev@example.com".to_string(),
//! };
//!
//! // Serialize to JSON string
//! let json_data = json::encode(&user)?;
//!
//! // Deserialize back to struct
//! let decoded: User = json::decode(&json_data)?;
//!
//! assert_eq!(user, decoded);
//! # Ok(())
//! # }
//! ```
//!
//! ## SIMD Support and Safety
//!
//! `fastserial` automatically detects CPU features at runtime to use the fastest possible
//! implementation.
//!
//! - **AVX2**: Used on modern x86_64 CPUs for 32-byte parallel scanning.
//! - **SSE4.2**: Fallback for older x86_64 CPUs.
//! - **Scalar**: Default implementation for other architectures or when SIMD is disabled.
//!
//! All `unsafe` code used for SIMD is encapsulated within the [`simd`] module and is
//! thoroughly tested for memory safety.
//!
//! ## Feature Flags
//!
//! - `std` (default): Enables support for `std` types like `String`, `Vec`, and `std::error::Error`.
//! - `json` (default): Enables JSON serialization/deserialization.
//! - `binary` (default): Enables FastSerial binary format.
//! - `chrono`: Enables serialization support for `chrono` date/time types.
//! - `profile`: Enables internal profiling for performance debugging.

#![no_std]

#[cfg(feature = "std")]
extern crate std;

#[cfg(feature = "std")]
extern crate alloc;

/// Derive macro for the `Decode` trait.
pub use fastserial_derive::Decode;
/// Derive macro for the `Encode` trait.
pub use fastserial_derive::Encode;

/// Codec implementations for various formats (JSON, Binary, etc.)
pub mod codec;
/// I/O traits and buffers for reading and writing.
pub mod io;
/// Schema hashing and validation.
pub mod schema;
/// SIMD-accelerated low-level operations.
pub mod simd;

mod error;
mod format;
pub mod value;

pub use error::Error;
pub use format::Format;
pub use value::Value;

/// Trait for types that can be encoded into a format.
///
/// This trait is the primary interface for serialization. It is recommended to use
/// `#[derive(Encode)]` to implement this trait for your structs.
///
/// # Examples
///
/// ```rust
/// use fastserial::Encode;
///
/// #[derive(Encode)]
/// struct MyData {
///     value: u32,
/// }
/// ```
pub trait Encode {
    /// A unique 64-bit hash representing the schema of the type.
    ///
    /// This hash is used by formats like Binary to ensure that the data
    /// being deserialized matches the struct definition.
    const SCHEMA_HASH: u64;

    /// Encodes the type into the provided `WriteBuffer`.
    ///
    /// This method is usually generated by the `derive` macro and handles
    /// the field-by-field serialization.
    fn encode<W: io::WriteBuffer>(&self, w: &mut W) -> Result<(), Error>;

    /// Encodes the type using a specific `Format` implementation.
    ///
    /// This allows the type to customize its representation for different
    /// formats (e.g., JSON vs Binary).
    fn encode_with_format<F: Format, W: io::WriteBuffer>(&self, w: &mut W) -> Result<(), Error> {
        F::encode_struct(self, w)
    }
}

/// Trait for types that can be decoded from a byte buffer.
///
/// The `'de` lifetime represents the lifetime of the input buffer. Types that
/// implement `Decode<'de>` can borrow data directly from this buffer (zero-copy).
///
/// # Examples
///
/// ```rust
/// use fastserial::Decode;
///
/// #[derive(Decode)]
/// struct MyData {
///     owned_string: String,
/// }
/// ```
pub trait Decode<'de>: Sized {
    /// Decodes the type from the provided `ReadBuffer`.
    ///
    /// This method handles field-by-field deserialization and may borrow
    /// from the buffer `r`.
    fn decode(r: &mut io::ReadBuffer<'de>) -> Result<Self, Error>;
}

/// JSON format support.
///
/// This module provides a high-level API for serializing and deserializing data in JSON format.
/// It is powered by SIMD scanning and specialized code generation to achieve maximum throughput.
pub mod json {
    use super::*;

    /// Encodes a value to a JSON byte vector.
    ///
    /// This is a convenience function that allocates a new `Vec<u8>` and serializes the
    /// provided value into it.
    ///
    /// # Examples
    ///
    /// ```rust
    /// use fastserial::json;
    ///
    /// let data = vec![1, 2, 3];
    /// let json_bytes = json::encode(&data).unwrap();
    /// assert_eq!(json_bytes, b"[1,2,3]");
    /// ```
    ///
    /// # Errors
    /// Returns an [`Error`] if the value cannot be encoded (e.g., contains invalid floating point numbers).
    pub fn encode<T: Encode>(val: &T) -> Result<alloc::vec::Vec<u8>, Error> {
        let mut buf = alloc::vec::Vec::with_capacity(256);
        val.encode(&mut buf)?;
        Ok(buf)
    }

    /// Encodes a value into an existing byte vector.
    ///
    /// This is more efficient than [`encode`] if you already have a buffer that can be reused.
    ///
    /// # Arguments
    /// * `val` - The value to encode.
    /// * `buf` - The destination buffer. Encoded data will be appended to it.
    ///
    /// # Examples
    ///
    /// ```rust
    /// use fastserial::json;
    ///
    /// let mut buf = Vec::new();
    /// json::encode_into(&42, &mut buf).unwrap();
    /// assert_eq!(buf, b"42");
    /// ```
    pub fn encode_into<T: Encode>(val: &T, buf: &mut alloc::vec::Vec<u8>) -> Result<(), Error> {
        val.encode(buf)
    }

    /// Decodes a value from a JSON byte slice.
    ///
    /// This function performs zero-copy deserialization where possible, meaning it borrows
    /// strings and byte slices directly from the input `input`.
    ///
    /// # Examples
    ///
    /// ```rust
    /// use fastserial::{Decode, json};
    ///
    /// #[derive(Decode)]
    /// struct Message {
    ///     text: String,
    /// }
    ///
    /// let input = r#"{"text":"Hello"}"#;
    /// let msg: Message = json::decode(input.as_bytes()).unwrap();
    /// assert_eq!(msg.text, "Hello");
    /// ```
    ///
    /// # Errors
    /// Returns an [`Error`] if the JSON is malformed, missing required fields, or contains
    /// invalid data types for the target struct.
    pub fn decode<'de, T: Decode<'de>>(input: &'de [u8]) -> Result<T, Error> {
        let mut r = io::ReadBuffer::new(input);
        let val = T::decode(&mut r)?;
        codec::json::skip_whitespace(&mut r);
        if !r.is_eof() {
            return Err(Error::TrailingData);
        }
        Ok(val)
    }

    pub fn decode_str<'de, T: Decode<'de>>(input: &'de str) -> Result<T, Error> {
        decode(input.as_bytes())
    }

    pub fn encode_pretty<T: Encode>(val: &T) -> Result<alloc::vec::Vec<u8>, Error> {
        let compact = encode(val)?;
        let value: crate::Value = decode(&compact)?;
        let mut buf = alloc::vec::Vec::with_capacity(compact.len() * 2);
        pretty_print_value(&value, &mut buf, 0)?;
        Ok(buf)
    }

    fn pretty_print_value(
        val: &crate::Value,
        buf: &mut alloc::vec::Vec<u8>,
        indent: usize,
    ) -> Result<(), Error> {
        use crate::io::WriteBuffer;
        match val {
            crate::Value::Null => buf.write_bytes(b"null"),
            crate::Value::Bool(true) => buf.write_bytes(b"true"),
            crate::Value::Bool(false) => buf.write_bytes(b"false"),
            crate::Value::Number(_) | crate::Value::String(_) => val.encode(buf),
            crate::Value::Array(arr) => {
                if arr.is_empty() {
                    return buf.write_bytes(b"[]");
                }
                buf.write_bytes(b"[\n")?;
                let child_indent = indent + 2;
                for (i, item) in arr.iter().enumerate() {
                    for _ in 0..child_indent {
                        buf.write_byte(b' ')?;
                    }
                    pretty_print_value(item, buf, child_indent)?;
                    if i + 1 < arr.len() {
                        buf.write_byte(b',')?;
                    }
                    buf.write_byte(b'\n')?;
                }
                for _ in 0..indent {
                    buf.write_byte(b' ')?;
                }
                buf.write_byte(b']')
            }
            crate::Value::Object(map) => {
                if map.is_empty() {
                    return buf.write_bytes(b"{}");
                }
                buf.write_bytes(b"{\n")?;
                let child_indent = indent + 2;
                let len = map.len();
                for (i, (k, v)) in map.iter().enumerate() {
                    for _ in 0..child_indent {
                        buf.write_byte(b' ')?;
                    }
                    codec::json::write_str(k, buf)?;
                    buf.write_bytes(b": ")?;
                    pretty_print_value(v, buf, child_indent)?;
                    if i + 1 < len {
                        buf.write_byte(b',')?;
                    }
                    buf.write_byte(b'\n')?;
                }
                for _ in 0..indent {
                    buf.write_byte(b' ')?;
                }
                buf.write_byte(b'}')
            }
        }
    }
}

/// FastSerial binary format support.
///
/// The binary format is a high-performance, compact representation of data.
/// It includes a 16-byte header with a magic number, version, and schema hash
/// to ensure data integrity and compatibility.
///
/// ### Header Specification (16 bytes)
///
/// | Bytes | Name | Description |
/// |-------|------|-------------|
/// | 0-3   | Magic | Fixed string `FBIN`. |
/// | 4-5   | Version | Format version (current: `0x0001`). |
/// | 6-13  | Schema Hash | 64-bit hash of the target type's schema. |
/// | 14-15 | Reserved | Reserved for future use. |
pub mod binary {
    use super::*;

    const MAGIC: [u8; 4] = *b"FBIN";
    const VERSION: u16 = 0x0001;

    /// Encodes a value to a new byte vector using the FastSerial binary format.
    ///
    /// This function automatically prepends the 16-byte protocol header.
    /// Use [`encode_raw`] for faster encoding without header.
    ///
    /// # Examples
    ///
    /// ```rust
    /// use fastserial::binary;
    ///
    /// let data = 12345u64;
    /// let bin_data = binary::encode(&data).unwrap();
    /// assert!(bin_data.starts_with(b"FBIN"));
    /// ```
    ///
    /// # Returns
    /// A `Vec<u8>` containing the header followed by the serialized data.
    pub fn encode<T: Encode>(val: &T) -> Result<alloc::vec::Vec<u8>, Error> {
        let mut buf = alloc::vec::Vec::with_capacity(256);
        buf.extend_from_slice(&MAGIC);
        buf.extend_from_slice(&VERSION.to_le_bytes());
        buf.extend_from_slice(&T::SCHEMA_HASH.to_le_bytes());
        buf.extend_from_slice(&[0, 0]);
        val.encode(&mut buf)?;
        Ok(buf)
    }

    /// Decodes a value from a byte slice using the FastSerial binary format.
    ///
    /// This function validates the magic number, version, and schema hash
    /// before performing deserialization.
    ///
    /// # Examples
    ///
    /// ```rust
    /// use fastserial::{Encode, Decode, binary};
    ///
    /// #[derive(Encode, Decode, PartialEq, Debug)]
    /// struct Data { id: u32 }
    ///
    /// let original = Data { id: 100 };
    /// let bytes = binary::encode(&original).unwrap();
    /// let decoded: Data = binary::decode(&bytes).unwrap();
    /// assert_eq!(original, decoded);
    /// ```
    ///
    /// # Errors
    /// Returns [`Error::InvalidMagic`] if the header is missing, or [`Error::InvalidUtf8`]
    /// if the schema hash doesn't match (coming soon).
    pub fn decode<'de, T: Decode<'de>>(input: &'de [u8]) -> Result<T, Error> {
        if input.len() < 16 {
            return Err(Error::UnexpectedEof);
        }
        if input[0..4] != MAGIC {
            return Err(Error::InvalidMagic);
        }
        let version = u16::from_le_bytes([input[4], input[5]]);
        if version != VERSION {
            return Err(Error::UnsupportedVersion { version });
        }
        // TODO: Validate T::SCHEMA_HASH against input[6..14]
        let mut r = io::ReadBuffer::new(&input[16..]);
        let val = T::decode(&mut r)?;
        if !r.is_eof() {
            return Err(Error::TrailingData);
        }
        Ok(val)
    }

    /// Encodes a value to binary without the 16-byte header.
    ///
    /// This is faster for internal use where the schema is known.
    ///
    /// # Examples
    ///
    /// ```rust
    /// use fastserial::binary;
    ///
    /// let data = 12345u64;
    /// let bin_data = binary::encode_raw(&data).unwrap();
    /// assert!(!bin_data.starts_with(b"FBIN"));
    /// ```
    pub fn encode_raw<T: Encode>(val: &T) -> Result<alloc::vec::Vec<u8>, Error> {
        let mut buf = alloc::vec::Vec::with_capacity(256);
        val.encode(&mut buf)?;
        Ok(buf)
    }

    /// Decodes a value from binary without parsing the header.
    ///
    /// Use this with data encoded via [`encode_raw`].
    ///
    /// # Examples
    ///
    /// ```rust
    /// use fastserial::{Encode, Decode, binary};
    ///
    /// #[derive(Encode, Decode, PartialEq, Debug)]
    /// struct Data { id: u32 }
    ///
    /// let original = Data { id: 100 };
    /// let bytes = binary::encode_raw(&original).unwrap();
    /// let decoded: Data = binary::decode_raw(&bytes).unwrap();
    /// assert_eq!(original, decoded);
    /// ```
    pub fn decode_raw<'de, T: Decode<'de>>(input: &'de [u8]) -> Result<T, Error> {
        let mut r = io::ReadBuffer::new(input);
        let val = T::decode(&mut r)?;
        if !r.is_eof() {
            return Err(Error::TrailingData);
        }
        Ok(val)
    }
}

mod option_impl {
    use super::*;

    impl<T: Encode> Encode for Option<T> {
        const SCHEMA_HASH: u64 = 0;

        #[inline]
        fn encode<W: io::WriteBuffer>(&self, w: &mut W) -> Result<(), Error> {
            match self {
                None => w.write_bytes(b"null"),
                Some(v) => v.encode(w),
            }
        }

        #[inline]
        fn encode_with_format<F: Format, W: io::WriteBuffer>(
            &self,
            w: &mut W,
        ) -> Result<(), Error> {
            match self {
                None => F::write_null(w),
                Some(v) => v.encode_with_format::<F, W>(w),
            }
        }
    }

    impl<'de, T: Decode<'de>> Decode<'de> for Option<T> {
        #[inline]
        fn decode(r: &mut io::ReadBuffer<'de>) -> Result<Self, Error> {
            codec::json::skip_whitespace(r);
            if r.peek() == b'n' {
                r.expect_bytes(b"null")?;
                Ok(None)
            } else {
                Ok(Some(T::decode(r)?))
            }
        }
    }
}

mod vec_impl {
    use super::*;

    impl<T: Encode> Encode for alloc::vec::Vec<T> {
        const SCHEMA_HASH: u64 = 0;

        #[inline]
        fn encode<W: io::WriteBuffer>(&self, w: &mut W) -> Result<(), Error> {
            w.write_byte(b'[')?;
            let mut iter = self.iter();
            if let Some(item) = iter.next() {
                item.encode(w)?;
                for item in iter {
                    w.write_byte(b',')?;
                    item.encode(w)?;
                }
            }
            w.write_byte(b']')
        }

        #[inline]
        fn encode_with_format<F: Format, W: io::WriteBuffer>(
            &self,
            w: &mut W,
        ) -> Result<(), Error> {
            F::begin_array(self.len(), w)?;
            let mut iter = self.iter();
            if let Some(item) = iter.next() {
                item.encode_with_format::<F, W>(w)?;
                for item in iter {
                    F::array_separator(w)?;
                    item.encode_with_format::<F, W>(w)?;
                }
            }
            F::end_array(w)
        }
    }

    impl<'de, T: Decode<'de>> Decode<'de> for alloc::vec::Vec<T> {
        #[inline]
        fn decode(r: &mut io::ReadBuffer<'de>) -> Result<Self, Error> {
            r.expect_byte(b'[')?;
            let mut vec = alloc::vec::Vec::new();
            codec::json::skip_whitespace(r);
            if r.peek() == b']' {
                r.advance(1);
                return Ok(vec);
            }
            loop {
                vec.push(T::decode(r)?);
                codec::json::skip_comma_or_close(r, b']')?;
                if r.peek() == b']' {
                    r.advance(1);
                    break;
                }
            }
            Ok(vec)
        }
    }
}

macro_rules! impl_primitive {
    ($($ty:ty => $write_fn:ident, $read_fn:ident, $hash:literal),* $(,)?) => {
        $(
            impl Encode for $ty {
                const SCHEMA_HASH: u64 = $hash;

                #[inline(always)]
                fn encode<W: io::WriteBuffer>(&self, w: &mut W) -> Result<(), Error> {
                    codec::json::$write_fn(*self, w)
                }

                #[inline(always)]
                fn encode_with_format<F: Format, W: io::WriteBuffer>(&self, w: &mut W) -> Result<(), Error> {
                    F::write_u64(*self as u64, w)
                }
            }

            impl<'de> Decode<'de> for $ty {
                #[inline(always)]
                fn decode(r: &mut io::ReadBuffer<'de>) -> Result<Self, Error> {
                    codec::json::$read_fn(r)
                }
            }
        )*
    };
}

impl_primitive! {
    u8 => write_u8, read_u8, 0x7a3c8d2e,
    u16 => write_u16, read_u16, 0x8b4d9e3f,
    u32 => write_u32, read_u32, 0x9c5e0f4a,
    u64 => write_u64, read_u64, 0xad6f1a5b,
    i8 => write_i8, read_i8, 0xbe7a2b6c,
    i16 => write_i16, read_i16, 0xcf8b3c7d,
    i32 => write_i32, read_i32, 0xde9c4d8e,
    i64 => write_i64, read_i64, 0xefad5e9f,
    f32 => write_f32, read_f32, 0xf0be6faa,
    f64 => write_f64, read_f64, 0x01cf8fbb,
    bool => write_bool, read_bool, 0x12d090cc,
}

impl Encode for () {
    const SCHEMA_HASH: u64 = 0x23e1a1dd;

    #[inline]
    fn encode<W: io::WriteBuffer>(&self, w: &mut W) -> Result<(), Error> {
        codec::json::write_null(w)
    }
}

impl<'de> Decode<'de> for () {
    #[inline]
    fn decode(r: &mut io::ReadBuffer<'de>) -> Result<Self, Error> {
        codec::json::read_null(r)
    }
}

impl Encode for alloc::string::String {
    const SCHEMA_HASH: u64 = 0x34f2b2ee3d6e8cbb;

    #[inline]
    fn encode<W: io::WriteBuffer>(&self, w: &mut W) -> Result<(), Error> {
        codec::json::write_str(self, w)
    }

    #[inline]
    fn encode_with_format<F: Format, W: io::WriteBuffer>(&self, w: &mut W) -> Result<(), Error> {
        F::write_str(self, w)
    }
}

impl<'de> Decode<'de> for alloc::string::String {
    #[inline]
    fn decode(r: &mut io::ReadBuffer<'de>) -> Result<Self, Error> {
        Ok(codec::json::read_string_cow(r)?.into_owned())
    }
}

impl Encode for &str {
    const SCHEMA_HASH: u64 = 0x45c3c3ff4e7d9dcc;

    #[inline]
    fn encode<W: io::WriteBuffer>(&self, w: &mut W) -> Result<(), Error> {
        codec::json::write_str(self, w)
    }

    #[inline]
    fn encode_with_format<F: Format, W: io::WriteBuffer>(&self, w: &mut W) -> Result<(), Error> {
        F::write_str(self, w)
    }
}

impl<'de> Decode<'de> for &'de str {
    #[inline]
    fn decode(r: &mut io::ReadBuffer<'de>) -> Result<Self, Error> {
        codec::json::read_string(r)
    }
}

impl Encode for &[u8] {
    const SCHEMA_HASH: u64 = 0x56d4d4ff5f8deed;

    #[inline]
    fn encode<W: io::WriteBuffer>(&self, w: &mut W) -> Result<(), Error> {
        codec::json::write_bytes(self, w)
    }

    #[inline]
    fn encode_with_format<F: Format, W: io::WriteBuffer>(&self, w: &mut W) -> Result<(), Error> {
        F::write_bytes(self, w)
    }
}

impl<'de> Decode<'de> for &'de [u8] {
    #[inline]
    fn decode(r: &mut io::ReadBuffer<'de>) -> Result<Self, Error> {
        codec::json::read_bytes(r)
    }
}

#[cfg(feature = "chrono")]
mod chrono_impl {
    use super::*;
    use chrono::{DateTime, Utc};

    impl Encode for DateTime<Utc> {
        const SCHEMA_HASH: u64 = 0x67e5e5ff6f9efffe;

        #[inline]
        fn encode<W: io::WriteBuffer>(&self, w: &mut W) -> Result<(), Error> {
            let s = self.to_rfc3339();
            codec::json::write_str(&s, w)
        }

        #[inline]
        fn encode_with_format<F: Format, W: io::WriteBuffer>(
            &self,
            w: &mut W,
        ) -> Result<(), Error> {
            let s = self.to_rfc3339();
            F::write_str(&s, w)
        }
    }

    impl<'de> Decode<'de> for DateTime<Utc> {
        #[inline]
        fn decode(r: &mut io::ReadBuffer<'de>) -> Result<Self, Error> {
            let s = codec::json::read_string(r)?;
            DateTime::parse_from_rfc3339(s)
                .map(|dt| dt.with_timezone(&Utc))
                .map_err(|_| Error::InvalidUtf8 {
                    byte_offset: r.get_pos(),
                })
        }
    }
}

#[cfg(feature = "std")]
mod hashmap_impl {
    use super::*;
    use std::collections::HashMap;

    impl<K: Encode + core::fmt::Display, V: Encode> Encode for HashMap<K, V> {
        const SCHEMA_HASH: u64 = 0;

        #[inline]
        fn encode<W: io::WriteBuffer>(&self, w: &mut W) -> Result<(), Error> {
            w.write_byte(b'{')?;
            let mut first = true;
            for (k, v) in self {
                if !first {
                    w.write_byte(b',')?;
                }
                first = false;
                let key_str = alloc::format!("{}", k);
                codec::json::write_str(&key_str, w)?;
                w.write_byte(b':')?;
                v.encode(w)?;
            }
            w.write_byte(b'}')
        }
    }

    impl<'de, V: Decode<'de>> Decode<'de> for HashMap<alloc::string::String, V> {
        #[inline]
        fn decode(r: &mut io::ReadBuffer<'de>) -> Result<Self, Error> {
            codec::json::skip_whitespace(r);
            r.expect_byte(b'{')?;
            let mut map = HashMap::new();
            codec::json::skip_whitespace(r);
            if r.peek() == b'}' {
                r.advance(1);
                return Ok(map);
            }
            loop {
                codec::json::skip_whitespace(r);
                let key = codec::json::read_string_cow(r)?.into_owned();
                codec::json::skip_whitespace(r);
                r.expect_byte(b':')?;
                let val = V::decode(r)?;
                map.insert(key, val);
                codec::json::skip_comma_or_close(r, b'}')?;
                if r.peek() == b'}' {
                    r.advance(1);
                    break;
                }
            }
            Ok(map)
        }
    }
}

mod btreemap_impl {
    use super::*;
    use alloc::collections::BTreeMap;

    impl<K: Encode + core::fmt::Display, V: Encode> Encode for BTreeMap<K, V> {
        const SCHEMA_HASH: u64 = 0;

        #[inline]
        fn encode<W: io::WriteBuffer>(&self, w: &mut W) -> Result<(), Error> {
            w.write_byte(b'{')?;
            let mut first = true;
            for (k, v) in self {
                if !first {
                    w.write_byte(b',')?;
                }
                first = false;
                let key_str = alloc::format!("{}", k);
                codec::json::write_str(&key_str, w)?;
                w.write_byte(b':')?;
                v.encode(w)?;
            }
            w.write_byte(b'}')
        }
    }

    impl<'de, V: Decode<'de>> Decode<'de> for BTreeMap<alloc::string::String, V> {
        #[inline]
        fn decode(r: &mut io::ReadBuffer<'de>) -> Result<Self, Error> {
            codec::json::skip_whitespace(r);
            r.expect_byte(b'{')?;
            let mut map = BTreeMap::new();
            codec::json::skip_whitespace(r);
            if r.peek() == b'}' {
                r.advance(1);
                return Ok(map);
            }
            loop {
                codec::json::skip_whitespace(r);
                let key = codec::json::read_string_cow(r)?.into_owned();
                codec::json::skip_whitespace(r);
                r.expect_byte(b':')?;
                let val = V::decode(r)?;
                map.insert(key, val);
                codec::json::skip_comma_or_close(r, b'}')?;
                if r.peek() == b'}' {
                    r.advance(1);
                    break;
                }
            }
            Ok(map)
        }
    }
}

macro_rules! impl_tuple {
    ($($idx:tt $T:ident),+) => {
        impl<$($T: Encode),+> Encode for ($($T,)+) {
            const SCHEMA_HASH: u64 = 0;

            #[inline]
            fn encode<W: io::WriteBuffer>(&self, w: &mut W) -> Result<(), Error> {
                w.write_byte(b'[')?;
                impl_tuple!(@encode self w $($idx $T),+);
                w.write_byte(b']')
            }
        }

        impl<'de, $($T: Decode<'de>),+> Decode<'de> for ($($T,)+) {
            #[inline]
            fn decode(r: &mut io::ReadBuffer<'de>) -> Result<Self, Error> {
                codec::json::skip_whitespace(r);
                r.expect_byte(b'[')?;
                impl_tuple!(@decode r $($idx $T),+);
                codec::json::skip_whitespace(r);
                r.expect_byte(b']')?;
                Ok(($($T,)+))
            }
        }
    };

    (@encode $self:ident $w:ident $first_idx:tt $first_T:ident $(, $idx:tt $T:ident)*) => {
        $self.$first_idx.encode($w)?;
        $(
            $w.write_byte(b',')?;
            $self.$idx.encode($w)?;
        )*
    };

    (@decode $r:ident $first_idx:tt $first_T:ident $(, $idx:tt $T:ident)*) => {
        codec::json::skip_whitespace($r);
        #[allow(non_snake_case)]
        let $first_T = $first_T::decode($r)?;
        $(
            codec::json::skip_comma_or_close($r, b']')?;
            #[allow(non_snake_case)]
            let $T = $T::decode($r)?;
        )*
    };
}

impl_tuple!(0 A);
impl_tuple!(0 A, 1 B);
impl_tuple!(0 A, 1 B, 2 C);
impl_tuple!(0 A, 1 B, 2 C, 3 D);
impl_tuple!(0 A, 1 B, 2 C, 3 D, 4 E2);
impl_tuple!(0 A, 1 B, 2 C, 3 D, 4 E2, 5 F2);
impl_tuple!(0 A, 1 B, 2 C, 3 D, 4 E2, 5 F2, 6 G);
impl_tuple!(0 A, 1 B, 2 C, 3 D, 4 E2, 5 F2, 6 G, 7 H);
impl_tuple!(0 A, 1 B, 2 C, 3 D, 4 E2, 5 F2, 6 G, 7 H, 8 I2);
impl_tuple!(0 A, 1 B, 2 C, 3 D, 4 E2, 5 F2, 6 G, 7 H, 8 I2, 9 J);
impl_tuple!(0 A, 1 B, 2 C, 3 D, 4 E2, 5 F2, 6 G, 7 H, 8 I2, 9 J, 10 K);
impl_tuple!(0 A, 1 B, 2 C, 3 D, 4 E2, 5 F2, 6 G, 7 H, 8 I2, 9 J, 10 K, 11 L);

#[cfg(feature = "msgpack")]
pub mod msgpack {
    pub use crate::codec::msgpack::*;
}