edgefirst-schemas 3.2.0

// SPDX-License-Identifier: Apache-2.0
// Copyright © 2025 Au-Zone Technologies. All Rights Reserved.

//! ROS 2 `sensor_msgs` message types.
//!
//! CdrFixed: `NavSatStatus`, `RegionOfInterest`
//!
//! Buffer-backed: `Image`, `CompressedImage`, `Imu`, `NavSatFix`,
//! `PointCloud2`, `PointField` (with `PointFieldView`), `CameraInfo`
//!
//! Pointcloud access: [`pointcloud`] module provides zero-copy
//! [`DynPointCloud`](pointcloud::DynPointCloud) and
//! [`PointCloud<P>`](pointcloud::PointCloud) views over PointCloud2 data.

pub mod pointcloud;

use crate::builtin_interfaces::Time;
use crate::cdr::*;
use crate::geometry_msgs::{Quaternion, Vector3};
use crate::std_msgs::Header;

// ── CdrFixed types ──────────────────────────────────────────────────

#[derive(PartialEq, Clone, Copy, Debug)]
pub struct NavSatStatus {
    pub status: i8,
    pub service: u16,
}

impl CdrFixed for NavSatStatus {
    // WARNING: position-dependent. 4 bytes only when embedded at an even
    // CDR-relative offset; 3 bytes at odd relative offsets (no pre-u16 pad).
    // Do NOT compute post-field positions as `offsets[0] + CDR_SIZE` — use
    // a cursor-captured offset instead. See CdrFixed trait docs and
    // NavSatFix::from_cdr for the correct pattern. EDGEAI-1243.
    const CDR_SIZE: usize = 4; // i8(1) + pad(1) + u16(2)
    fn read_cdr(cursor: &mut CdrCursor<'_>) -> Result<Self, CdrError> {
        let status = cursor.read_i8()?;
        let service = cursor.read_u16()?;
        Ok(NavSatStatus { status, service })
    }
    fn write_cdr(&self, writer: &mut CdrWriter<'_>) {
        writer.write_i8(self.status);
        writer.write_u16(self.service);
    }
    fn size_cdr(sizer: &mut CdrSizer) {
        sizer.size_i8();
        sizer.size_u16();
    }
}

#[derive(PartialEq, Clone, Copy, Debug)]
pub struct RegionOfInterest {
    pub x_offset: u32,
    pub y_offset: u32,
    pub height: u32,
    pub width: u32,
    pub do_rectify: bool,
}

impl CdrFixed for RegionOfInterest {
    const CDR_SIZE: usize = 17; // 4 x u32(16) + bool(1)
    fn read_cdr(cursor: &mut CdrCursor<'_>) -> Result<Self, CdrError> {
        Ok(RegionOfInterest {
            x_offset: cursor.read_u32()?,
            y_offset: cursor.read_u32()?,
            height: cursor.read_u32()?,
            width: cursor.read_u32()?,
            do_rectify: cursor.read_bool()?,
        })
    }
    fn write_cdr(&self, writer: &mut CdrWriter<'_>) {
        writer.write_u32(self.x_offset);
        writer.write_u32(self.y_offset);
        writer.write_u32(self.height);
        writer.write_u32(self.width);
        writer.write_bool(self.do_rectify);
    }
    fn size_cdr(sizer: &mut CdrSizer) {
        sizer.size_u32();
        sizer.size_u32();
        sizer.size_u32();
        sizer.size_u32();
        sizer.size_bool();
    }
}

// ── Helper arrays ───────────────────────────────────────────────────

fn read_f64_array9(c: &mut CdrCursor<'_>) -> Result<[f64; 9], CdrError> {
    Ok([
        c.read_f64()?,
        c.read_f64()?,
        c.read_f64()?,
        c.read_f64()?,
        c.read_f64()?,
        c.read_f64()?,
        c.read_f64()?,
        c.read_f64()?,
        c.read_f64()?,
    ])
}

fn write_f64_array9(w: &mut CdrWriter<'_>, a: &[f64; 9]) {
    for v in a {
        w.write_f64(*v);
    }
}

fn size_f64_array9(s: &mut CdrSizer) {
    for _ in 0..9 {
        s.size_f64();
    }
}

fn read_f64_array12(c: &mut CdrCursor<'_>) -> Result<[f64; 12], CdrError> {
    Ok([
        c.read_f64()?,
        c.read_f64()?,
        c.read_f64()?,
        c.read_f64()?,
        c.read_f64()?,
        c.read_f64()?,
        c.read_f64()?,
        c.read_f64()?,
        c.read_f64()?,
        c.read_f64()?,
        c.read_f64()?,
        c.read_f64()?,
    ])
}

fn write_f64_array12(w: &mut CdrWriter<'_>, a: &[f64; 12]) {
    for v in a {
        w.write_f64(*v);
    }
}

fn size_f64_array12(s: &mut CdrSizer) {
    for _ in 0..12 {
        s.size_f64();
    }
}

// ── PointField helpers ──────────────────────────────────────────────

/// Zero-copy view of a PointField element within a CDR sequence.
pub struct PointFieldView<'a> {
    pub name: &'a str,
    pub offset: u32,
    pub datatype: u8,
    pub count: u32,
}

fn scan_point_field_element<'a>(c: &mut CdrCursor<'a>) -> Result<PointFieldView<'a>, CdrError> {
    let name = c.read_string()?;
    let offset = c.read_u32()?;
    let datatype = c.read_u8()?;
    let count = c.read_u32()?;
    Ok(PointFieldView {
        name,
        offset,
        datatype,
        count,
    })
}

fn write_point_field_element(w: &mut CdrWriter<'_>, f: &PointFieldView<'_>) {
    w.write_string(f.name);
    w.write_u32(f.offset);
    w.write_u8(f.datatype);
    w.write_u32(f.count);
}

fn size_point_field_element(s: &mut CdrSizer, name: &str) {
    s.size_string(name);
    s.size_u32();
    s.size_u8();
    s.size_u32();
}

/// Non-allocating iterator over PointField descriptors in a PointCloud2.
///
/// Yields [`PointFieldView`] items by parsing the CDR field array on
/// each call to `next()`. No heap allocation occurs — the iterator
/// borrows directly from the PointCloud2 buffer.
///
/// Implements [`ExactSizeIterator`], so `iter.len()` returns the
/// remaining field count.
pub struct PointFieldIter<'a> {
    cursor: CdrCursor<'a>,
    remaining: usize,
}

impl<'a> Iterator for PointFieldIter<'a> {
    type Item = PointFieldView<'a>;

    fn next(&mut self) -> Option<Self::Item> {
        if self.remaining == 0 {
            return None;
        }
        self.remaining -= 1;
        Some(
            scan_point_field_element(&mut self.cursor)
                .expect("point field elements validated during from_cdr"),
        )
    }

    fn size_hint(&self) -> (usize, Option<usize>) {
        (self.remaining, Some(self.remaining))
    }
}

impl ExactSizeIterator for PointFieldIter<'_> {}

// ── Buffer-backed types ─────────────────────────────────────────────

// ── CompressedImage<B> ──────────────────────────────────────────────
//
// CDR layout:
//   4: stamp (8 bytes)
//  12: frame_id (string) → offsets[0]
//   ~: format (string) → offsets[1]
//   ~: data (byte seq) → offsets[2]

pub struct CompressedImage<B> {
    buf: B,
    offsets: [usize; 3],
}

impl<B: AsRef<[u8]>> CompressedImage<B> {
    pub fn from_cdr(buf: B) -> Result<Self, CdrError> {
        let header = Header::<&[u8]>::from_cdr(buf.as_ref())?;
        let o0 = header.end_offset();
        let mut c = CdrCursor::resume(buf.as_ref(), o0);
        let _ = c.read_string()?; // format
        let o1 = c.offset();
        let _ = c.read_bytes()?; // data
        let o2 = c.offset();
        Ok(CompressedImage {
            offsets: [o0, o1, o2],
            buf,
        })
    }

    /// Returns a `Header` view (re-parses CDR prefix; prefer `stamp()`/`frame_id()`).
    pub fn header(&self) -> Header<&[u8]> {
        Header::from_cdr(self.buf.as_ref()).expect("header bytes validated during from_cdr")
    }
    pub fn stamp(&self) -> Time {
        rd_time(self.buf.as_ref(), CDR_HEADER_SIZE)
    }
    pub fn frame_id(&self) -> &str {
        rd_string(self.buf.as_ref(), CDR_HEADER_SIZE + 8).0
    }
    pub fn format(&self) -> &str {
        rd_string(self.buf.as_ref(), self.offsets[0]).0
    }
    pub fn data(&self) -> &[u8] {
        rd_bytes(self.buf.as_ref(), self.offsets[1]).0
    }
    pub fn as_cdr(&self) -> &[u8] {
        self.buf.as_ref()
    }
    pub fn cdr_size(&self) -> usize {
        self.buf.as_ref().len()
    }
    pub fn to_cdr(&self) -> Vec<u8> {
        self.buf.as_ref().to_vec()
    }
}

impl CompressedImage<Vec<u8>> {
    #[deprecated(
        since = "3.2.0",
        note = "use CompressedImage::builder() for allocation-free buffer reuse; CompressedImage::new will be removed in 4.0"
    )]
    pub fn new(stamp: Time, frame_id: &str, format: &str, data: &[u8]) -> Result<Self, CdrError> {
        let mut sizer = CdrSizer::new();
        Time::size_cdr(&mut sizer);
        sizer.size_string(frame_id);
        let o0 = sizer.offset();
        sizer.size_string(format);
        let o1 = sizer.offset();
        sizer.size_bytes(data.len());
        let o2 = sizer.offset();

        let mut buf = vec![0u8; sizer.size()];
        let mut w = CdrWriter::new(&mut buf)?;
        stamp.write_cdr(&mut w);
        w.write_string(frame_id);
        w.write_string(format);
        w.write_bytes(data);
        w.finish()?;

        Ok(CompressedImage {
            offsets: [o0, o1, o2],
            buf,
        })
    }

    pub fn into_cdr(self) -> Vec<u8> {
        self.buf
    }

    /// Start a new `CompressedImageBuilder` with zero-valued defaults.
    ///
    /// Generic in `'a` so the compiler infers it from subsequent setter
    /// borrows rather than forcing `'static`.
    pub fn builder<'a>() -> CompressedImageBuilder<'a> {
        CompressedImageBuilder::new()
    }
}

// ── CompressedImageBuilder<'a> ──────────────────────────────────────

/// Builder for `CompressedImage<Vec<u8>>` with buffer-reuse finalizers.
pub struct CompressedImageBuilder<'a> {
    stamp: Time,
    frame_id: std::borrow::Cow<'a, str>,
    format: std::borrow::Cow<'a, str>,
    data: &'a [u8],
}

impl<'a> Default for CompressedImageBuilder<'a> {
    fn default() -> Self {
        Self {
            stamp: Time { sec: 0, nanosec: 0 },
            frame_id: std::borrow::Cow::Borrowed(""),
            format: std::borrow::Cow::Borrowed(""),
            data: &[],
        }
    }
}

impl<'a> CompressedImageBuilder<'a> {
    pub fn new() -> Self {
        Self::default()
    }

    pub fn stamp(&mut self, t: Time) -> &mut Self {
        self.stamp = t;
        self
    }
    pub fn frame_id(&mut self, s: impl Into<std::borrow::Cow<'a, str>>) -> &mut Self {
        self.frame_id = s.into();
        self
    }
    pub fn format(&mut self, s: impl Into<std::borrow::Cow<'a, str>>) -> &mut Self {
        self.format = s.into();
        self
    }
    pub fn data(&mut self, d: &'a [u8]) -> &mut Self {
        self.data = d;
        self
    }

    fn size(&self) -> usize {
        let mut s = CdrSizer::new();
        Time::size_cdr(&mut s);
        s.size_string(&self.frame_id);
        s.size_string(&self.format);
        s.size_bytes(self.data.len());
        s.size()
    }

    fn write_into(&self, buf: &mut [u8]) -> Result<(), CdrError> {
        let mut w = CdrWriter::new(buf)?;
        self.stamp.write_cdr(&mut w);
        w.write_string(&self.frame_id);
        w.write_string(&self.format);
        w.write_bytes(self.data);
        w.finish()
    }

    /// Allocate a fresh `Vec<u8>` and return a fully-parsed `CompressedImage<Vec<u8>>`.
    pub fn build(&self) -> Result<CompressedImage<Vec<u8>>, CdrError> {
        let mut buf = vec![0u8; self.size()];
        self.write_into(&mut buf)?;
        CompressedImage::from_cdr(buf)
    }

    /// Serialize into the caller's `Vec<u8>`, resizing to exactly the encoded size.
    pub fn encode_into_vec(&self, buf: &mut Vec<u8>) -> Result<(), CdrError> {
        buf.resize(self.size(), 0);
        self.write_into(buf)
    }

    /// Serialize into `buf` and return bytes written. Errors with `BufferTooShort`
    /// when `buf` is smaller than the required size; nothing is mutated in that case.
    pub fn encode_into_slice(&self, buf: &mut [u8]) -> Result<usize, CdrError> {
        let need = self.size();
        if buf.len() < need {
            return Err(CdrError::BufferTooShort {
                need,
                have: buf.len(),
            });
        }
        self.write_into(&mut buf[..need])?;
        Ok(need)
    }
}

impl<B: AsRef<[u8]> + AsMut<[u8]>> CompressedImage<B> {
    pub fn set_stamp(&mut self, t: Time) -> Result<(), CdrError> {
        let b = self.buf.as_mut();
        wr_i32(b, CDR_HEADER_SIZE, t.sec)?;
        wr_u32(b, CDR_HEADER_SIZE + 4, t.nanosec)
    }
}

// ── Image<B> ────────────────────────────────────────────────────────
//
// CDR layout:
//   4: stamp (8 bytes)
//  12: frame_id (string) → offsets[0]
//   ~: height (u32), width (u32)
//   ~: encoding (string) → offsets[1]
//   ~: is_bigendian (u8)
//   ~: step (u32)
//   ~: data (byte seq) → offsets[2]

pub struct Image<B> {
    buf: B,
    offsets: [usize; 3],
}

impl<B: AsRef<[u8]>> Image<B> {
    pub fn from_cdr(buf: B) -> Result<Self, CdrError> {
        let header = Header::<&[u8]>::from_cdr(buf.as_ref())?;
        let o0 = header.end_offset();
        let mut c = CdrCursor::resume(buf.as_ref(), o0);
        let _ = c.read_u32()?; // height
        let _ = c.read_u32()?; // width
        let _ = c.read_string()?; // encoding
        let o1 = c.offset();
        let _ = c.read_u8()?; // is_bigendian
        let _ = c.read_u32()?; // step
        let _ = c.read_bytes()?; // data
        let o2 = c.offset();
        Ok(Image {
            offsets: [o0, o1, o2],
            buf,
        })
    }

    /// Returns a `Header` view (re-parses CDR prefix; prefer `stamp()`/`frame_id()`).
    pub fn header(&self) -> Header<&[u8]> {
        Header::from_cdr(self.buf.as_ref()).expect("header bytes validated during from_cdr")
    }
    pub fn stamp(&self) -> Time {
        rd_time(self.buf.as_ref(), CDR_HEADER_SIZE)
    }
    pub fn frame_id(&self) -> &str {
        rd_string(self.buf.as_ref(), CDR_HEADER_SIZE + 8).0
    }

    pub fn height(&self) -> u32 {
        let p = align(self.offsets[0], 4);
        rd_u32(self.buf.as_ref(), p)
    }

    pub fn width(&self) -> u32 {
        let p = align(self.offsets[0], 4) + 4;
        rd_u32(self.buf.as_ref(), p)
    }

    pub fn encoding(&self) -> &str {
        let p = align(self.offsets[0], 4) + 8;
        rd_string(self.buf.as_ref(), p).0
    }

    pub fn is_bigendian(&self) -> u8 {
        rd_u8(self.buf.as_ref(), self.offsets[1])
    }

    pub fn step(&self) -> u32 {
        let p = align(self.offsets[1] + 1, 4);
        rd_u32(self.buf.as_ref(), p)
    }

    pub fn data(&self) -> &[u8] {
        let p = align(self.offsets[1] + 1, 4) + 4;
        rd_bytes(self.buf.as_ref(), p).0
    }

    pub fn as_cdr(&self) -> &[u8] {
        self.buf.as_ref()
    }
    pub fn cdr_size(&self) -> usize {
        self.buf.as_ref().len()
    }
    pub fn to_cdr(&self) -> Vec<u8> {
        self.buf.as_ref().to_vec()
    }
}

impl Image<Vec<u8>> {
    #[deprecated(
        since = "3.2.0",
        note = "use Image::builder() for allocation-free buffer reuse; Image::new will be removed in 4.0"
    )]
    pub fn new(
        stamp: Time,
        frame_id: &str,
        height: u32,
        width: u32,
        encoding: &str,
        is_bigendian: u8,
        step: u32,
        data: &[u8],
    ) -> Result<Self, CdrError> {
        let mut sizer = CdrSizer::new();
        Time::size_cdr(&mut sizer);
        sizer.size_string(frame_id);
        let o0 = sizer.offset();
        sizer.size_u32(); // height
        sizer.size_u32(); // width
        sizer.size_string(encoding);
        let o1 = sizer.offset();
        sizer.size_u8(); // is_bigendian
        sizer.size_u32(); // step
        sizer.size_bytes(data.len());
        let o2 = sizer.offset();

        let mut buf = vec![0u8; sizer.size()];
        let mut w = CdrWriter::new(&mut buf)?;
        stamp.write_cdr(&mut w);
        w.write_string(frame_id);
        w.write_u32(height);
        w.write_u32(width);
        w.write_string(encoding);
        w.write_u8(is_bigendian);
        w.write_u32(step);
        w.write_bytes(data);
        w.finish()?;

        Ok(Image {
            offsets: [o0, o1, o2],
            buf,
        })
    }

    pub fn into_cdr(self) -> Vec<u8> {
        self.buf
    }

    /// Start a new `ImageBuilder` with zero-valued defaults.
    ///
    /// Returned with a generic lifetime parameter `'a` so the compiler
    /// infers it from subsequent setter calls — `.data(&local_pixels)`
    /// binds `'a` to the caller's scope without forcing `'static`.
    pub fn builder<'a>() -> ImageBuilder<'a> {
        ImageBuilder::new()
    }
}

impl<B: AsRef<[u8]> + AsMut<[u8]>> Image<B> {
    pub fn set_stamp(&mut self, t: Time) -> Result<(), CdrError> {
        let b = self.buf.as_mut();
        wr_i32(b, CDR_HEADER_SIZE, t.sec)?;
        wr_u32(b, CDR_HEADER_SIZE + 4, t.nanosec)
    }

    pub fn set_height(&mut self, h: u32) -> Result<(), CdrError> {
        let p = align(self.offsets[0], 4);
        wr_u32(self.buf.as_mut(), p, h)
    }

    pub fn set_width(&mut self, w: u32) -> Result<(), CdrError> {
        let p = align(self.offsets[0], 4) + 4;
        wr_u32(self.buf.as_mut(), p, w)
    }

    pub fn set_is_bigendian(&mut self, v: u8) -> Result<(), CdrError> {
        wr_u8(self.buf.as_mut(), self.offsets[1], v)
    }

    pub fn set_step(&mut self, v: u32) -> Result<(), CdrError> {
        let p = align(self.offsets[1] + 1, 4);
        wr_u32(self.buf.as_mut(), p, v)
    }
}

// ── ImageBuilder<'a> ────────────────────────────────────────────────

/// Builder for `Image<Vec<u8>>` with buffer-reuse finalizers.
///
/// Strings use `Cow<'a, str>` so that `frame_id("lit")` borrows a `&'static str`
/// and `frame_id(owned)` takes ownership. Bulk `data` is always borrowed for
/// zero-copy input semantics; the borrow must remain valid until `build()`,
/// `encode_into_vec()`, or `encode_into_slice()` is called.
pub struct ImageBuilder<'a> {
    stamp: Time,
    frame_id: std::borrow::Cow<'a, str>,
    height: u32,
    width: u32,
    encoding: std::borrow::Cow<'a, str>,
    is_bigendian: u8,
    step: u32,
    data: &'a [u8],
}

impl<'a> Default for ImageBuilder<'a> {
    fn default() -> Self {
        Self {
            stamp: Time { sec: 0, nanosec: 0 },
            frame_id: std::borrow::Cow::Borrowed(""),
            height: 0,
            width: 0,
            encoding: std::borrow::Cow::Borrowed(""),
            is_bigendian: 0,
            step: 0,
            data: &[],
        }
    }
}

impl<'a> ImageBuilder<'a> {
    pub fn new() -> Self {
        Self::default()
    }

    pub fn stamp(&mut self, t: Time) -> &mut Self {
        self.stamp = t;
        self
    }
    pub fn frame_id(&mut self, s: impl Into<std::borrow::Cow<'a, str>>) -> &mut Self {
        self.frame_id = s.into();
        self
    }
    pub fn height(&mut self, h: u32) -> &mut Self {
        self.height = h;
        self
    }
    pub fn width(&mut self, w: u32) -> &mut Self {
        self.width = w;
        self
    }
    pub fn encoding(&mut self, s: impl Into<std::borrow::Cow<'a, str>>) -> &mut Self {
        self.encoding = s.into();
        self
    }
    pub fn is_bigendian(&mut self, v: u8) -> &mut Self {
        self.is_bigendian = v;
        self
    }
    pub fn step(&mut self, v: u32) -> &mut Self {
        self.step = v;
        self
    }
    pub fn data(&mut self, d: &'a [u8]) -> &mut Self {
        self.data = d;
        self
    }

    fn size(&self) -> usize {
        let mut s = CdrSizer::new();
        Time::size_cdr(&mut s);
        s.size_string(&self.frame_id);
        s.size_u32(); // height
        s.size_u32(); // width
        s.size_string(&self.encoding);
        s.size_u8(); // is_bigendian
        s.size_u32(); // step
        s.size_bytes(self.data.len());
        s.size()
    }

    fn write_into(&self, buf: &mut [u8]) -> Result<(), CdrError> {
        let mut w = CdrWriter::new(buf)?;
        self.stamp.write_cdr(&mut w);
        w.write_string(&self.frame_id);
        w.write_u32(self.height);
        w.write_u32(self.width);
        w.write_string(&self.encoding);
        w.write_u8(self.is_bigendian);
        w.write_u32(self.step);
        w.write_bytes(self.data);
        w.finish()
    }

    /// Allocate a fresh `Vec<u8>` and return a fully-parsed `Image<Vec<u8>>`.
    pub fn build(&self) -> Result<Image<Vec<u8>>, CdrError> {
        let mut buf = vec![0u8; self.size()];
        self.write_into(&mut buf)?;
        Image::from_cdr(buf)
    }

    /// Serialize into the caller's `Vec<u8>`, resizing to exactly the encoded
    /// size. After return, `buf.len()` is the CDR size and `&buf[..]` is a
    /// complete CDR message. Reuses existing allocation when capacity suffices.
    pub fn encode_into_vec(&self, buf: &mut Vec<u8>) -> Result<(), CdrError> {
        buf.resize(self.size(), 0);
        self.write_into(buf)
    }

    /// Serialize into `buf` and return bytes written. Errors with
    /// `BufferTooShort` when `buf` is smaller than the required size; nothing
    /// is mutated in that case.
    pub fn encode_into_slice(&self, buf: &mut [u8]) -> Result<usize, CdrError> {
        let need = self.size();
        if buf.len() < need {
            return Err(CdrError::BufferTooShort {
                need,
                have: buf.len(),
            });
        }
        self.write_into(&mut buf[..need])?;
        Ok(need)
    }
}

// ── Imu<B> ──────────────────────────────────────────────────────────
//
// CDR layout: Header → offsets[0], then:
//   Quaternion(32) + [f64;9](72) + Vector3(24) + [f64;9](72)
//   + Vector3(24) + [f64;9](72) = 296 bytes fixed payload

pub struct Imu<B> {
    buf: B,
    offsets: [usize; 1],
}

impl<B: AsRef<[u8]>> Imu<B> {
    pub fn from_cdr(buf: B) -> Result<Self, CdrError> {
        let header = Header::<&[u8]>::from_cdr(buf.as_ref())?;
        let o0 = header.end_offset();
        let mut c = CdrCursor::resume(buf.as_ref(), o0);
        Quaternion::read_cdr(&mut c)?;
        read_f64_array9(&mut c)?;
        Vector3::read_cdr(&mut c)?;
        read_f64_array9(&mut c)?;
        Vector3::read_cdr(&mut c)?;
        read_f64_array9(&mut c)?;
        Ok(Imu { offsets: [o0], buf })
    }

    /// Returns a `Header` view (re-parses CDR prefix; prefer `stamp()`/`frame_id()`).
    pub fn header(&self) -> Header<&[u8]> {
        Header::from_cdr(self.buf.as_ref()).expect("header bytes validated during from_cdr")
    }
    pub fn stamp(&self) -> Time {
        rd_time(self.buf.as_ref(), CDR_HEADER_SIZE)
    }
    pub fn frame_id(&self) -> &str {
        rd_string(self.buf.as_ref(), CDR_HEADER_SIZE + 8).0
    }

    // Imu fixed layout after orientation (Quaternion=32):
    //   orientation_cov[9](72), angular_vel(24), angular_vel_cov[9](72),
    //   linear_acc(24), linear_acc_cov[9](72)
    fn fixed_base(&self) -> usize {
        cdr_align(self.offsets[0], 8)
    }

    pub fn orientation(&self) -> Quaternion {
        let mut c = CdrCursor::resume(self.buf.as_ref(), self.offsets[0]);
        Quaternion::read_cdr(&mut c).expect("orientation field validated during from_cdr")
    }

    pub fn orientation_covariance(&self) -> [f64; 9] {
        let mut c = CdrCursor::resume(self.buf.as_ref(), self.fixed_base() + 32);
        read_f64_array9(&mut c).expect("covariance field validated during from_cdr")
    }

    pub fn angular_velocity(&self) -> Vector3 {
        let mut c = CdrCursor::resume(self.buf.as_ref(), self.fixed_base() + 104);
        Vector3::read_cdr(&mut c).expect("vector3 field validated during from_cdr")
    }

    pub fn angular_velocity_covariance(&self) -> [f64; 9] {
        let mut c = CdrCursor::resume(self.buf.as_ref(), self.fixed_base() + 128);
        read_f64_array9(&mut c).expect("covariance field validated during from_cdr")
    }

    pub fn linear_acceleration(&self) -> Vector3 {
        let mut c = CdrCursor::resume(self.buf.as_ref(), self.fixed_base() + 200);
        Vector3::read_cdr(&mut c).expect("vector3 field validated during from_cdr")
    }

    pub fn linear_acceleration_covariance(&self) -> [f64; 9] {
        let mut c = CdrCursor::resume(self.buf.as_ref(), self.fixed_base() + 224);
        read_f64_array9(&mut c).expect("covariance field validated during from_cdr")
    }

    pub fn as_cdr(&self) -> &[u8] {
        self.buf.as_ref()
    }
    pub fn to_cdr(&self) -> Vec<u8> {
        self.buf.as_ref().to_vec()
    }
}

impl Imu<Vec<u8>> {
    #[deprecated(
        since = "3.2.0",
        note = "use Imu::builder() for allocation-free buffer reuse; Imu::new will be removed in 4.0"
    )]
    pub fn new(
        stamp: Time,
        frame_id: &str,
        orientation: Quaternion,
        orientation_covariance: [f64; 9],
        angular_velocity: Vector3,
        angular_velocity_covariance: [f64; 9],
        linear_acceleration: Vector3,
        linear_acceleration_covariance: [f64; 9],
    ) -> Result<Self, CdrError> {
        let mut sizer = CdrSizer::new();
        Time::size_cdr(&mut sizer);
        sizer.size_string(frame_id);
        let o0 = sizer.offset();
        Quaternion::size_cdr(&mut sizer);
        size_f64_array9(&mut sizer);
        Vector3::size_cdr(&mut sizer);
        size_f64_array9(&mut sizer);
        Vector3::size_cdr(&mut sizer);
        size_f64_array9(&mut sizer);

        let mut buf = vec![0u8; sizer.size()];
        let mut w = CdrWriter::new(&mut buf)?;
        stamp.write_cdr(&mut w);
        w.write_string(frame_id);
        orientation.write_cdr(&mut w);
        write_f64_array9(&mut w, &orientation_covariance);
        angular_velocity.write_cdr(&mut w);
        write_f64_array9(&mut w, &angular_velocity_covariance);
        linear_acceleration.write_cdr(&mut w);
        write_f64_array9(&mut w, &linear_acceleration_covariance);
        w.finish()?;

        Ok(Imu { offsets: [o0], buf })
    }

    pub fn into_cdr(self) -> Vec<u8> {
        self.buf
    }

    /// Start a new `ImuBuilder` with zero-valued defaults.
    pub fn builder<'a>() -> ImuBuilder<'a> {
        ImuBuilder::new()
    }
}

// ── ImuBuilder<'a> ──────────────────────────────────────────────────

/// Builder for `Imu<Vec<u8>>` with buffer-reuse finalizers.
pub struct ImuBuilder<'a> {
    stamp: Time,
    frame_id: std::borrow::Cow<'a, str>,
    orientation: Quaternion,
    orientation_covariance: [f64; 9],
    angular_velocity: Vector3,
    angular_velocity_covariance: [f64; 9],
    linear_acceleration: Vector3,
    linear_acceleration_covariance: [f64; 9],
}

impl<'a> Default for ImuBuilder<'a> {
    fn default() -> Self {
        Self {
            stamp: Time { sec: 0, nanosec: 0 },
            frame_id: std::borrow::Cow::Borrowed(""),
            orientation: Quaternion {
                x: 0.0,
                y: 0.0,
                z: 0.0,
                w: 0.0,
            },
            orientation_covariance: [0.0; 9],
            angular_velocity: Vector3 {
                x: 0.0,
                y: 0.0,
                z: 0.0,
            },
            angular_velocity_covariance: [0.0; 9],
            linear_acceleration: Vector3 {
                x: 0.0,
                y: 0.0,
                z: 0.0,
            },
            linear_acceleration_covariance: [0.0; 9],
        }
    }
}

impl<'a> ImuBuilder<'a> {
    pub fn new() -> Self {
        Self::default()
    }

    pub fn stamp(&mut self, t: Time) -> &mut Self {
        self.stamp = t;
        self
    }
    pub fn frame_id(&mut self, s: impl Into<std::borrow::Cow<'a, str>>) -> &mut Self {
        self.frame_id = s.into();
        self
    }
    pub fn orientation(&mut self, q: Quaternion) -> &mut Self {
        self.orientation = q;
        self
    }
    pub fn orientation_covariance(&mut self, c: [f64; 9]) -> &mut Self {
        self.orientation_covariance = c;
        self
    }
    pub fn angular_velocity(&mut self, v: Vector3) -> &mut Self {
        self.angular_velocity = v;
        self
    }
    pub fn angular_velocity_covariance(&mut self, c: [f64; 9]) -> &mut Self {
        self.angular_velocity_covariance = c;
        self
    }
    pub fn linear_acceleration(&mut self, v: Vector3) -> &mut Self {
        self.linear_acceleration = v;
        self
    }
    pub fn linear_acceleration_covariance(&mut self, c: [f64; 9]) -> &mut Self {
        self.linear_acceleration_covariance = c;
        self
    }

    fn size(&self) -> usize {
        let mut s = CdrSizer::new();
        Time::size_cdr(&mut s);
        s.size_string(&self.frame_id);
        Quaternion::size_cdr(&mut s);
        size_f64_array9(&mut s);
        Vector3::size_cdr(&mut s);
        size_f64_array9(&mut s);
        Vector3::size_cdr(&mut s);
        size_f64_array9(&mut s);
        s.size()
    }

    fn write_into(&self, buf: &mut [u8]) -> Result<(), CdrError> {
        let mut w = CdrWriter::new(buf)?;
        self.stamp.write_cdr(&mut w);
        w.write_string(&self.frame_id);
        self.orientation.write_cdr(&mut w);
        write_f64_array9(&mut w, &self.orientation_covariance);
        self.angular_velocity.write_cdr(&mut w);
        write_f64_array9(&mut w, &self.angular_velocity_covariance);
        self.linear_acceleration.write_cdr(&mut w);
        write_f64_array9(&mut w, &self.linear_acceleration_covariance);
        w.finish()
    }

    pub fn build(&self) -> Result<Imu<Vec<u8>>, CdrError> {
        let mut buf = vec![0u8; self.size()];
        self.write_into(&mut buf)?;
        Imu::from_cdr(buf)
    }

    pub fn encode_into_vec(&self, buf: &mut Vec<u8>) -> Result<(), CdrError> {
        buf.resize(self.size(), 0);
        self.write_into(buf)
    }

    pub fn encode_into_slice(&self, buf: &mut [u8]) -> Result<usize, CdrError> {
        let need = self.size();
        if buf.len() < need {
            return Err(CdrError::BufferTooShort {
                need,
                have: buf.len(),
            });
        }
        self.write_into(&mut buf[..need])?;
        Ok(need)
    }
}

impl<B: AsRef<[u8]> + AsMut<[u8]>> Imu<B> {
    pub fn set_stamp(&mut self, t: Time) -> Result<(), CdrError> {
        let b = self.buf.as_mut();
        wr_i32(b, CDR_HEADER_SIZE, t.sec)?;
        wr_u32(b, CDR_HEADER_SIZE + 4, t.nanosec)
    }

    pub fn set_orientation(&mut self, q: Quaternion) -> Result<(), CdrError> {
        let p = self.fixed_base();
        let b = self.buf.as_mut();
        wr_f64(b, p, q.x)?;
        wr_f64(b, p + 8, q.y)?;
        wr_f64(b, p + 16, q.z)?;
        wr_f64(b, p + 24, q.w)
    }

    pub fn set_orientation_covariance(&mut self, c: [f64; 9]) -> Result<(), CdrError> {
        let p = self.fixed_base() + 32;
        let b = self.buf.as_mut();
        for (i, v) in c.iter().enumerate() {
            wr_f64(b, p + i * 8, *v)?;
        }
        Ok(())
    }

    pub fn set_angular_velocity(&mut self, v: Vector3) -> Result<(), CdrError> {
        let p = self.fixed_base() + 104;
        let b = self.buf.as_mut();
        wr_f64(b, p, v.x)?;
        wr_f64(b, p + 8, v.y)?;
        wr_f64(b, p + 16, v.z)
    }

    pub fn set_angular_velocity_covariance(&mut self, c: [f64; 9]) -> Result<(), CdrError> {
        let p = self.fixed_base() + 128;
        let b = self.buf.as_mut();
        for (i, v) in c.iter().enumerate() {
            wr_f64(b, p + i * 8, *v)?;
        }
        Ok(())
    }

    pub fn set_linear_acceleration(&mut self, v: Vector3) -> Result<(), CdrError> {
        let p = self.fixed_base() + 200;
        let b = self.buf.as_mut();
        wr_f64(b, p, v.x)?;
        wr_f64(b, p + 8, v.y)?;
        wr_f64(b, p + 16, v.z)
    }

    pub fn set_linear_acceleration_covariance(&mut self, c: [f64; 9]) -> Result<(), CdrError> {
        let p = self.fixed_base() + 224;
        let b = self.buf.as_mut();
        for (i, v) in c.iter().enumerate() {
            wr_f64(b, p + i * 8, *v)?;
        }
        Ok(())
    }
}

// ── NavSatFix<B> ────────────────────────────────────────────────────
//
// CDR layout: Header → offsets[0] (status start), then:
//   NavSatStatus (3 or 4 bytes — internal padding depends on start parity)
//   + pad to 8 → offsets[1] (latitude start)
//   + latitude(f64) + longitude(f64) + altitude(f64)
//   + position_covariance([f64;9]) + position_covariance_type(u8)
//
// `offsets[1]` must be captured from the cursor, not derived from
// `offsets[0] + NavSatStatus::CDR_SIZE`, because CDR_SIZE is 4 only when
// offsets[0] lands at an even CDR-relative position; at odd relative
// positions the `int8`+`uint16` pair occupies 3 bytes (no pre-u16 pad).
// See EDGEAI-1243.

pub struct NavSatFix<B> {
    buf: B,
    offsets: [usize; 2],
}

impl<B: AsRef<[u8]>> NavSatFix<B> {
    pub fn from_cdr(buf: B) -> Result<Self, CdrError> {
        let header = Header::<&[u8]>::from_cdr(buf.as_ref())?;
        let o0 = header.end_offset();
        let mut c = CdrCursor::resume(buf.as_ref(), o0);
        NavSatStatus::read_cdr(&mut c)?;
        c.align(8);
        let o1 = c.offset();
        c.read_f64()?; // latitude
        c.read_f64()?; // longitude
        c.read_f64()?; // altitude
        read_f64_array9(&mut c)?; // position_covariance
        c.read_u8()?; // position_covariance_type
        Ok(NavSatFix {
            offsets: [o0, o1],
            buf,
        })
    }

    /// Returns a `Header` view (re-parses CDR prefix; prefer `stamp()`/`frame_id()`).
    pub fn header(&self) -> Header<&[u8]> {
        Header::from_cdr(self.buf.as_ref()).expect("header bytes validated during from_cdr")
    }
    pub fn stamp(&self) -> Time {
        rd_time(self.buf.as_ref(), CDR_HEADER_SIZE)
    }
    pub fn frame_id(&self) -> &str {
        rd_string(self.buf.as_ref(), CDR_HEADER_SIZE + 8).0
    }

    pub fn status(&self) -> NavSatStatus {
        let mut c = CdrCursor::resume(self.buf.as_ref(), self.offsets[0]);
        NavSatStatus::read_cdr(&mut c).expect("status field validated during from_cdr")
    }

    // NavSatFix fixed layout (starting at offsets[1]):
    //   lat(8), lon(8), alt(8), pos_cov[9](72), pos_cov_type(1)
    #[inline]
    fn fixed_base(&self) -> usize {
        self.offsets[1]
    }

    pub fn latitude(&self) -> f64 {
        rd_f64(self.buf.as_ref(), self.fixed_base())
    }
    pub fn longitude(&self) -> f64 {
        rd_f64(self.buf.as_ref(), self.fixed_base() + 8)
    }
    pub fn altitude(&self) -> f64 {
        rd_f64(self.buf.as_ref(), self.fixed_base() + 16)
    }

    pub fn position_covariance(&self) -> [f64; 9] {
        let mut c = CdrCursor::resume(self.buf.as_ref(), self.fixed_base() + 24);
        read_f64_array9(&mut c).expect("covariance field validated during from_cdr")
    }

    pub fn position_covariance_type(&self) -> u8 {
        rd_u8(self.buf.as_ref(), self.fixed_base() + 96)
    }

    pub fn as_cdr(&self) -> &[u8] {
        self.buf.as_ref()
    }
    pub fn to_cdr(&self) -> Vec<u8> {
        self.buf.as_ref().to_vec()
    }
}

impl NavSatFix<Vec<u8>> {
    #[deprecated(
        since = "3.2.0",
        note = "use NavSatFix::builder() for allocation-free buffer reuse; NavSatFix::new will be removed in 4.0"
    )]
    pub fn new(
        stamp: Time,
        frame_id: &str,
        status: NavSatStatus,
        latitude: f64,
        longitude: f64,
        altitude: f64,
        position_covariance: [f64; 9],
        position_covariance_type: u8,
    ) -> Result<Self, CdrError> {
        let mut sizer = CdrSizer::new();
        Time::size_cdr(&mut sizer);
        sizer.size_string(frame_id);
        let o0 = sizer.offset();
        NavSatStatus::size_cdr(&mut sizer);
        sizer.align(8);
        let o1 = sizer.offset();
        sizer.size_f64(); // latitude
        sizer.size_f64(); // longitude
        sizer.size_f64(); // altitude
        size_f64_array9(&mut sizer);
        sizer.size_u8(); // position_covariance_type

        let mut buf = vec![0u8; sizer.size()];
        let mut w = CdrWriter::new(&mut buf)?;
        stamp.write_cdr(&mut w);
        w.write_string(frame_id);
        status.write_cdr(&mut w);
        w.write_f64(latitude);
        w.write_f64(longitude);
        w.write_f64(altitude);
        write_f64_array9(&mut w, &position_covariance);
        w.write_u8(position_covariance_type);
        w.finish()?;

        Ok(NavSatFix {
            offsets: [o0, o1],
            buf,
        })
    }

    pub fn into_cdr(self) -> Vec<u8> {
        self.buf
    }

    /// Start a new `NavSatFixBuilder` with zero-valued defaults.
    pub fn builder<'a>() -> NavSatFixBuilder<'a> {
        NavSatFixBuilder::new()
    }
}

// ── NavSatFixBuilder<'a> ────────────────────────────────────────────

/// Builder for `NavSatFix<Vec<u8>>` with buffer-reuse finalizers.
pub struct NavSatFixBuilder<'a> {
    stamp: Time,
    frame_id: std::borrow::Cow<'a, str>,
    status: NavSatStatus,
    latitude: f64,
    longitude: f64,
    altitude: f64,
    position_covariance: [f64; 9],
    position_covariance_type: u8,
}

impl<'a> Default for NavSatFixBuilder<'a> {
    fn default() -> Self {
        Self {
            stamp: Time { sec: 0, nanosec: 0 },
            frame_id: std::borrow::Cow::Borrowed(""),
            status: NavSatStatus {
                status: 0,
                service: 0,
            },
            latitude: 0.0,
            longitude: 0.0,
            altitude: 0.0,
            position_covariance: [0.0; 9],
            position_covariance_type: 0,
        }
    }
}

impl<'a> NavSatFixBuilder<'a> {
    pub fn new() -> Self {
        Self::default()
    }

    pub fn stamp(&mut self, t: Time) -> &mut Self {
        self.stamp = t;
        self
    }
    pub fn frame_id(&mut self, s: impl Into<std::borrow::Cow<'a, str>>) -> &mut Self {
        self.frame_id = s.into();
        self
    }
    pub fn status(&mut self, s: NavSatStatus) -> &mut Self {
        self.status = s;
        self
    }
    pub fn latitude(&mut self, v: f64) -> &mut Self {
        self.latitude = v;
        self
    }
    pub fn longitude(&mut self, v: f64) -> &mut Self {
        self.longitude = v;
        self
    }
    pub fn altitude(&mut self, v: f64) -> &mut Self {
        self.altitude = v;
        self
    }
    pub fn position_covariance(&mut self, c: [f64; 9]) -> &mut Self {
        self.position_covariance = c;
        self
    }
    pub fn position_covariance_type(&mut self, v: u8) -> &mut Self {
        self.position_covariance_type = v;
        self
    }

    fn size(&self) -> usize {
        let mut s = CdrSizer::new();
        Time::size_cdr(&mut s);
        s.size_string(&self.frame_id);
        NavSatStatus::size_cdr(&mut s);
        s.align(8);
        s.size_f64(); // latitude
        s.size_f64(); // longitude
        s.size_f64(); // altitude
        size_f64_array9(&mut s);
        s.size_u8(); // position_covariance_type
        s.size()
    }

    fn write_into(&self, buf: &mut [u8]) -> Result<(), CdrError> {
        let mut w = CdrWriter::new(buf)?;
        self.stamp.write_cdr(&mut w);
        w.write_string(&self.frame_id);
        self.status.write_cdr(&mut w);
        w.write_f64(self.latitude);
        w.write_f64(self.longitude);
        w.write_f64(self.altitude);
        write_f64_array9(&mut w, &self.position_covariance);
        w.write_u8(self.position_covariance_type);
        w.finish()
    }

    pub fn build(&self) -> Result<NavSatFix<Vec<u8>>, CdrError> {
        let mut buf = vec![0u8; self.size()];
        self.write_into(&mut buf)?;
        NavSatFix::from_cdr(buf)
    }

    pub fn encode_into_vec(&self, buf: &mut Vec<u8>) -> Result<(), CdrError> {
        buf.resize(self.size(), 0);
        self.write_into(buf)
    }

    pub fn encode_into_slice(&self, buf: &mut [u8]) -> Result<usize, CdrError> {
        let need = self.size();
        if buf.len() < need {
            return Err(CdrError::BufferTooShort {
                need,
                have: buf.len(),
            });
        }
        self.write_into(&mut buf[..need])?;
        Ok(need)
    }
}

impl<B: AsRef<[u8]> + AsMut<[u8]>> NavSatFix<B> {
    pub fn set_stamp(&mut self, t: Time) -> Result<(), CdrError> {
        let b = self.buf.as_mut();
        wr_i32(b, CDR_HEADER_SIZE, t.sec)?;
        wr_u32(b, CDR_HEADER_SIZE + 4, t.nanosec)
    }

    /// Set the embedded `NavSatStatus`.
    ///
    /// The u16 `service` field is CDR-aligned to 2 bytes relative to the
    /// enclosing message header, so its byte offset depends on the parity
    /// of `offsets[0]`. We mirror the reader's cursor logic via
    /// [`cdr_align`] — see EDGEAI-1243.
    pub fn set_status(&mut self, s: NavSatStatus) -> Result<(), CdrError> {
        let status_pos = self.offsets[0];
        let service_pos = cdr_align(status_pos + 1, 2);
        let b = self.buf.as_mut();
        wr_i8(b, status_pos, s.status)?;
        wr_u16(b, service_pos, s.service)
    }

    pub fn set_latitude(&mut self, v: f64) -> Result<(), CdrError> {
        let p = self.fixed_base();
        wr_f64(self.buf.as_mut(), p, v)
    }

    pub fn set_longitude(&mut self, v: f64) -> Result<(), CdrError> {
        let p = self.fixed_base() + 8;
        wr_f64(self.buf.as_mut(), p, v)
    }

    pub fn set_altitude(&mut self, v: f64) -> Result<(), CdrError> {
        let p = self.fixed_base() + 16;
        wr_f64(self.buf.as_mut(), p, v)
    }

    pub fn set_position_covariance(&mut self, c: [f64; 9]) -> Result<(), CdrError> {
        let p = self.fixed_base() + 24;
        let b = self.buf.as_mut();
        for (i, v) in c.iter().enumerate() {
            wr_f64(b, p + i * 8, *v)?;
        }
        Ok(())
    }

    pub fn set_position_covariance_type(&mut self, v: u8) -> Result<(), CdrError> {
        let p = self.fixed_base() + 96;
        wr_u8(self.buf.as_mut(), p, v)
    }
}

// ── PointField<B> ───────────────────────────────────────────────────
//
// CDR layout: name (string) → offsets[0], then offset(u32), datatype(u8), count(u32)

pub struct PointField<B> {
    buf: B,
    offsets: [usize; 1],
}

impl<B: AsRef<[u8]>> PointField<B> {
    pub fn from_cdr(buf: B) -> Result<Self, CdrError> {
        let mut c = CdrCursor::new(buf.as_ref())?;
        let _ = c.read_string()?;
        let o0 = c.offset();
        c.read_u32()?;
        c.read_u8()?;
        c.read_u32()?;
        Ok(PointField { offsets: [o0], buf })
    }

    #[inline]
    pub fn name(&self) -> &str {
        rd_string(self.buf.as_ref(), CDR_HEADER_SIZE).0
    }

    pub fn offset(&self) -> u32 {
        let mut c = CdrCursor::resume(self.buf.as_ref(), self.offsets[0]);
        c.read_u32()
            .expect("point field element validated during from_cdr")
    }

    pub fn datatype(&self) -> u8 {
        let mut c = CdrCursor::resume(self.buf.as_ref(), self.offsets[0]);
        c.read_u32()
            .expect("point field element validated during from_cdr"); // skip offset
        c.read_u8()
            .expect("point field element validated during from_cdr")
    }

    pub fn count(&self) -> u32 {
        let mut c = CdrCursor::resume(self.buf.as_ref(), self.offsets[0]);
        c.read_u32()
            .expect("point field element validated during from_cdr"); // skip offset
        c.read_u8()
            .expect("point field element validated during from_cdr"); // skip datatype
        c.read_u32()
            .expect("point field element validated during from_cdr")
    }

    #[inline]
    pub fn as_cdr(&self) -> &[u8] {
        self.buf.as_ref()
    }
    pub fn to_cdr(&self) -> Vec<u8> {
        self.buf.as_ref().to_vec()
    }
}

impl PointField<Vec<u8>> {
    #[deprecated(
        since = "3.2.0",
        note = "use PointField::builder() for allocation-free buffer reuse; PointField::new will be removed in 4.0"
    )]
    pub fn new(name: &str, offset: u32, datatype: u8, count: u32) -> Result<Self, CdrError> {
        let mut sizer = CdrSizer::new();
        sizer.size_string(name);
        let o0 = sizer.offset();
        sizer.size_u32();
        sizer.size_u8();
        sizer.size_u32();

        let mut buf = vec![0u8; sizer.size()];
        let mut w = CdrWriter::new(&mut buf)?;
        w.write_string(name);
        w.write_u32(offset);
        w.write_u8(datatype);
        w.write_u32(count);
        w.finish()?;

        Ok(PointField { offsets: [o0], buf })
    }

    pub fn into_cdr(self) -> Vec<u8> {
        self.buf
    }

    /// Start a new `PointFieldBuilder` with zero-valued defaults.
    pub fn builder<'a>() -> PointFieldBuilder<'a> {
        PointFieldBuilder::new()
    }
}

// ── PointFieldBuilder<'a> ───────────────────────────────────────────

/// Builder for `PointField<Vec<u8>>` with buffer-reuse finalizers.
pub struct PointFieldBuilder<'a> {
    name: std::borrow::Cow<'a, str>,
    offset: u32,
    datatype: u8,
    count: u32,
}

impl<'a> Default for PointFieldBuilder<'a> {
    fn default() -> Self {
        Self {
            name: std::borrow::Cow::Borrowed(""),
            offset: 0,
            datatype: 0,
            count: 0,
        }
    }
}

impl<'a> PointFieldBuilder<'a> {
    pub fn new() -> Self {
        Self::default()
    }

    pub fn name(&mut self, s: impl Into<std::borrow::Cow<'a, str>>) -> &mut Self {
        self.name = s.into();
        self
    }
    pub fn offset(&mut self, v: u32) -> &mut Self {
        self.offset = v;
        self
    }
    pub fn datatype(&mut self, v: u8) -> &mut Self {
        self.datatype = v;
        self
    }
    pub fn count(&mut self, v: u32) -> &mut Self {
        self.count = v;
        self
    }

    fn size(&self) -> usize {
        let mut s = CdrSizer::new();
        s.size_string(&self.name);
        s.size_u32();
        s.size_u8();
        s.size_u32();
        s.size()
    }

    fn write_into(&self, buf: &mut [u8]) -> Result<(), CdrError> {
        let mut w = CdrWriter::new(buf)?;
        w.write_string(&self.name);
        w.write_u32(self.offset);
        w.write_u8(self.datatype);
        w.write_u32(self.count);
        w.finish()
    }

    pub fn build(&self) -> Result<PointField<Vec<u8>>, CdrError> {
        let mut buf = vec![0u8; self.size()];
        self.write_into(&mut buf)?;
        PointField::from_cdr(buf)
    }

    pub fn encode_into_vec(&self, buf: &mut Vec<u8>) -> Result<(), CdrError> {
        buf.resize(self.size(), 0);
        self.write_into(buf)
    }

    pub fn encode_into_slice(&self, buf: &mut [u8]) -> Result<usize, CdrError> {
        let need = self.size();
        if buf.len() < need {
            return Err(CdrError::BufferTooShort {
                need,
                have: buf.len(),
            });
        }
        self.write_into(&mut buf[..need])?;
        Ok(need)
    }
}

impl<B: AsRef<[u8]> + AsMut<[u8]>> PointField<B> {
    /// Byte offset of the `offset` u32 field (4-aligned relative to CDR header).
    #[inline]
    fn offset_pos(&self) -> usize {
        cdr_align(self.offsets[0], 4)
    }

    pub fn set_offset(&mut self, v: u32) -> Result<(), CdrError> {
        let p = self.offset_pos();
        wr_u32(self.buf.as_mut(), p, v)
    }

    pub fn set_datatype(&mut self, v: u8) -> Result<(), CdrError> {
        let p = self.offset_pos() + 4;
        wr_u8(self.buf.as_mut(), p, v)
    }

    pub fn set_count(&mut self, v: u32) -> Result<(), CdrError> {
        // datatype(u8) followed by count(u32) with 4-byte alignment.
        let p = cdr_align(self.offset_pos() + 5, 4);
        wr_u32(self.buf.as_mut(), p, v)
    }
}

// ── PointCloud2<B> ──────────────────────────────────────────────────
//
// CDR layout: Header → offsets[0],
//   height(u32), width(u32),
//   fields(Vec<PointField>) → offsets[1],
//   is_bigendian(bool), point_step(u32), row_step(u32),
//   data(Vec<u8>) → offsets[2], is_dense(bool)

pub struct PointCloud2<B> {
    buf: B,
    offsets: [usize; 3],
}

impl<B: AsRef<[u8]>> PointCloud2<B> {
    pub fn from_cdr(buf: B) -> Result<Self, CdrError> {
        let header = Header::<&[u8]>::from_cdr(buf.as_ref())?;
        let o0 = header.end_offset();
        let mut c = CdrCursor::resume(buf.as_ref(), o0);
        c.read_u32()?; // height
        c.read_u32()?; // width
        let raw_fields = c.read_u32()?;
        let fields_count = c.check_seq_count(raw_fields, 9)?;
        for _ in 0..fields_count {
            scan_point_field_element(&mut c)?;
        }
        let o1 = c.offset();
        c.read_bool()?; // is_bigendian
        c.read_u32()?; // point_step
        c.read_u32()?; // row_step
        let _ = c.read_bytes()?; // data
        let o2 = c.offset();
        c.read_bool()?; // is_dense
        Ok(PointCloud2 {
            offsets: [o0, o1, o2],
            buf,
        })
    }

    /// Returns a `Header` view (re-parses CDR prefix; prefer `stamp()`/`frame_id()`).
    pub fn header(&self) -> Header<&[u8]> {
        Header::from_cdr(self.buf.as_ref()).expect("header bytes validated during from_cdr")
    }
    pub fn stamp(&self) -> Time {
        rd_time(self.buf.as_ref(), CDR_HEADER_SIZE)
    }
    pub fn frame_id(&self) -> &str {
        rd_string(self.buf.as_ref(), CDR_HEADER_SIZE + 8).0
    }

    pub fn height(&self) -> u32 {
        rd_u32(self.buf.as_ref(), align(self.offsets[0], 4))
    }
    pub fn width(&self) -> u32 {
        rd_u32(self.buf.as_ref(), align(self.offsets[0], 4) + 4)
    }
    pub fn fields_len(&self) -> u32 {
        rd_u32(self.buf.as_ref(), align(self.offsets[0], 4) + 8)
    }

    pub fn fields(&self) -> Vec<PointFieldView<'_>> {
        let b = self.buf.as_ref();
        let p = align(self.offsets[0], 4) + 8;
        let count = rd_u32(b, p) as usize;
        let mut c = CdrCursor::resume(b, p + 4);
        (0..count)
            .map(|_| {
                scan_point_field_element(&mut c)
                    .expect("point field elements validated during from_cdr")
            })
            .collect()
    }

    /// Non-allocating iterator over the PointField descriptors.
    pub fn fields_iter(&self) -> PointFieldIter<'_> {
        let b = self.buf.as_ref();
        let p = align(self.offsets[0], 4) + 8;
        let count = rd_u32(b, p) as usize;
        let cursor = CdrCursor::resume(b, p + 4);
        PointFieldIter {
            cursor,
            remaining: count,
        }
    }

    /// Total number of points (height × width).
    pub fn point_count(&self) -> usize {
        (self.height() as usize) * (self.width() as usize)
    }

    /// Create a dynamic (runtime-typed) point cloud view over the data buffer.
    pub fn as_dyn_cloud(
        &self,
    ) -> Result<pointcloud::DynPointCloud<'_>, pointcloud::PointCloudError> {
        pointcloud::DynPointCloud::from_pointcloud2(self)
    }

    /// Create a statically-typed point cloud view, validating field layout.
    pub fn as_typed_cloud<P: pointcloud::Point>(
        &self,
    ) -> Result<pointcloud::PointCloud<'_, P>, pointcloud::PointCloudError> {
        pointcloud::PointCloud::from_pointcloud2(self)
    }

    pub fn is_bigendian(&self) -> bool {
        rd_bool(self.buf.as_ref(), self.offsets[1])
    }
    pub fn point_step(&self) -> u32 {
        rd_u32(self.buf.as_ref(), align(self.offsets[1] + 1, 4))
    }
    pub fn row_step(&self) -> u32 {
        rd_u32(self.buf.as_ref(), align(self.offsets[1] + 1, 4) + 4)
    }

    pub fn data(&self) -> &[u8] {
        rd_bytes(self.buf.as_ref(), align(self.offsets[1] + 1, 4) + 8).0
    }

    pub fn is_dense(&self) -> bool {
        rd_bool(self.buf.as_ref(), self.offsets[2])
    }

    pub fn as_cdr(&self) -> &[u8] {
        self.buf.as_ref()
    }
    pub fn to_cdr(&self) -> Vec<u8> {
        self.buf.as_ref().to_vec()
    }
}

impl PointCloud2<Vec<u8>> {
    #[deprecated(
        since = "3.2.0",
        note = "use PointCloud2::builder() for allocation-free buffer reuse; PointCloud2::new will be removed in 4.0"
    )]
    pub fn new(
        stamp: Time,
        frame_id: &str,
        height: u32,
        width: u32,
        fields: &[PointFieldView<'_>],
        is_bigendian: bool,
        point_step: u32,
        row_step: u32,
        data: &[u8],
        is_dense: bool,
    ) -> Result<Self, CdrError> {
        let mut sizer = CdrSizer::new();
        Time::size_cdr(&mut sizer);
        sizer.size_string(frame_id);
        let o0 = sizer.offset();
        sizer.size_u32(); // height
        sizer.size_u32(); // width
        sizer.size_u32(); // fields count
        for f in fields {
            size_point_field_element(&mut sizer, f.name);
        }
        let o1 = sizer.offset();
        sizer.size_bool(); // is_bigendian
        sizer.size_u32(); // point_step
        sizer.size_u32(); // row_step
        sizer.size_bytes(data.len());
        let o2 = sizer.offset();
        sizer.size_bool(); // is_dense

        let mut buf = vec![0u8; sizer.size()];
        let mut w = CdrWriter::new(&mut buf)?;
        stamp.write_cdr(&mut w);
        w.write_string(frame_id);
        w.write_u32(height);
        w.write_u32(width);
        w.write_u32(fields.len() as u32);
        for f in fields {
            write_point_field_element(&mut w, f);
        }
        w.write_bool(is_bigendian);
        w.write_u32(point_step);
        w.write_u32(row_step);
        w.write_bytes(data);
        w.write_bool(is_dense);
        w.finish()?;

        Ok(PointCloud2 {
            offsets: [o0, o1, o2],
            buf,
        })
    }

    pub fn into_cdr(self) -> Vec<u8> {
        self.buf
    }

    /// Start a new `PointCloud2Builder` with zero-valued defaults.
    ///
    /// Generic in `'a` so the compiler infers it from subsequent
    /// `.fields(...)` / `.data(...)` borrows rather than forcing `'static`.
    pub fn builder<'a>() -> PointCloud2Builder<'a> {
        PointCloud2Builder::new()
    }
}

// ── PointCloud2Builder<'a> ──────────────────────────────────────────

/// Builder for `PointCloud2<Vec<u8>>` with buffer-reuse finalizers.
///
/// `fields` and `data` are borrowed from caller-owned memory. Each
/// `PointFieldView` in the slice borrows its `name` field as well.
/// All borrows must remain valid until a finalizer is called.
pub struct PointCloud2Builder<'a> {
    stamp: Time,
    frame_id: std::borrow::Cow<'a, str>,
    height: u32,
    width: u32,
    fields: &'a [PointFieldView<'a>],
    is_bigendian: bool,
    point_step: u32,
    row_step: u32,
    data: &'a [u8],
    is_dense: bool,
}

impl<'a> Default for PointCloud2Builder<'a> {
    fn default() -> Self {
        Self {
            stamp: Time { sec: 0, nanosec: 0 },
            frame_id: std::borrow::Cow::Borrowed(""),
            height: 0,
            width: 0,
            fields: &[],
            is_bigendian: false,
            point_step: 0,
            row_step: 0,
            data: &[],
            is_dense: false,
        }
    }
}

impl<'a> PointCloud2Builder<'a> {
    pub fn new() -> Self {
        Self::default()
    }

    pub fn stamp(&mut self, t: Time) -> &mut Self {
        self.stamp = t;
        self
    }
    pub fn frame_id(&mut self, s: impl Into<std::borrow::Cow<'a, str>>) -> &mut Self {
        self.frame_id = s.into();
        self
    }
    pub fn height(&mut self, v: u32) -> &mut Self {
        self.height = v;
        self
    }
    pub fn width(&mut self, v: u32) -> &mut Self {
        self.width = v;
        self
    }
    pub fn fields(&mut self, f: &'a [PointFieldView<'a>]) -> &mut Self {
        self.fields = f;
        self
    }
    pub fn is_bigendian(&mut self, v: bool) -> &mut Self {
        self.is_bigendian = v;
        self
    }
    pub fn point_step(&mut self, v: u32) -> &mut Self {
        self.point_step = v;
        self
    }
    pub fn row_step(&mut self, v: u32) -> &mut Self {
        self.row_step = v;
        self
    }
    pub fn data(&mut self, d: &'a [u8]) -> &mut Self {
        self.data = d;
        self
    }
    pub fn is_dense(&mut self, v: bool) -> &mut Self {
        self.is_dense = v;
        self
    }

    fn size(&self) -> usize {
        let mut s = CdrSizer::new();
        Time::size_cdr(&mut s);
        s.size_string(&self.frame_id);
        s.size_u32(); // height
        s.size_u32(); // width
        s.size_u32(); // fields count
        for f in self.fields {
            size_point_field_element(&mut s, f.name);
        }
        s.size_bool(); // is_bigendian
        s.size_u32(); // point_step
        s.size_u32(); // row_step
        s.size_bytes(self.data.len());
        s.size_bool(); // is_dense
        s.size()
    }

    fn write_into(&self, buf: &mut [u8]) -> Result<(), CdrError> {
        let mut w = CdrWriter::new(buf)?;
        self.stamp.write_cdr(&mut w);
        w.write_string(&self.frame_id);
        w.write_u32(self.height);
        w.write_u32(self.width);
        w.write_u32(self.fields.len() as u32);
        for f in self.fields {
            write_point_field_element(&mut w, f);
        }
        w.write_bool(self.is_bigendian);
        w.write_u32(self.point_step);
        w.write_u32(self.row_step);
        w.write_bytes(self.data);
        w.write_bool(self.is_dense);
        w.finish()
    }

    pub fn build(&self) -> Result<PointCloud2<Vec<u8>>, CdrError> {
        let mut buf = vec![0u8; self.size()];
        self.write_into(&mut buf)?;
        PointCloud2::from_cdr(buf)
    }

    pub fn encode_into_vec(&self, buf: &mut Vec<u8>) -> Result<(), CdrError> {
        buf.resize(self.size(), 0);
        self.write_into(buf)
    }

    pub fn encode_into_slice(&self, buf: &mut [u8]) -> Result<usize, CdrError> {
        let need = self.size();
        if buf.len() < need {
            return Err(CdrError::BufferTooShort {
                need,
                have: buf.len(),
            });
        }
        self.write_into(&mut buf[..need])?;
        Ok(need)
    }
}

impl<B: AsRef<[u8]> + AsMut<[u8]>> PointCloud2<B> {
    pub fn set_stamp(&mut self, t: Time) -> Result<(), CdrError> {
        let b = self.buf.as_mut();
        wr_i32(b, CDR_HEADER_SIZE, t.sec)?;
        wr_u32(b, CDR_HEADER_SIZE + 4, t.nanosec)
    }

    pub fn set_height(&mut self, h: u32) -> Result<(), CdrError> {
        let p = align(self.offsets[0], 4);
        wr_u32(self.buf.as_mut(), p, h)
    }

    pub fn set_width(&mut self, w: u32) -> Result<(), CdrError> {
        let p = align(self.offsets[0], 4) + 4;
        wr_u32(self.buf.as_mut(), p, w)
    }

    pub fn set_is_bigendian(&mut self, v: bool) -> Result<(), CdrError> {
        wr_bool(self.buf.as_mut(), self.offsets[1], v)
    }

    pub fn set_point_step(&mut self, v: u32) -> Result<(), CdrError> {
        let p = align(self.offsets[1] + 1, 4);
        wr_u32(self.buf.as_mut(), p, v)
    }

    pub fn set_row_step(&mut self, v: u32) -> Result<(), CdrError> {
        let p = align(self.offsets[1] + 1, 4) + 4;
        wr_u32(self.buf.as_mut(), p, v)
    }

    pub fn set_is_dense(&mut self, v: bool) -> Result<(), CdrError> {
        wr_bool(self.buf.as_mut(), self.offsets[2], v)
    }
}

// ── CameraInfo<B> ───────────────────────────────────────────────────
//
// CDR layout: Header → offsets[0],
//   height(u32), width(u32), distortion_model(string) → offsets[1],
//   d(Vec<f64>) → offsets[2], k[9], r[9], p[12],
//   binning_x(u32), binning_y(u32), roi(RegionOfInterest)

pub struct CameraInfo<B> {
    buf: B,
    offsets: [usize; 3],
}

impl<B: AsRef<[u8]>> CameraInfo<B> {
    pub fn from_cdr(buf: B) -> Result<Self, CdrError> {
        let header = Header::<&[u8]>::from_cdr(buf.as_ref())?;
        let o0 = header.end_offset();
        let mut c = CdrCursor::resume(buf.as_ref(), o0);
        c.read_u32()?; // height
        c.read_u32()?; // width
        let _ = c.read_string()?; // distortion_model
        let o1 = c.offset();
        let d_count = c.read_u32()? as usize;
        c.skip_seq_8(d_count)?;
        let o2 = c.offset();
        read_f64_array9(&mut c)?; // k
        read_f64_array9(&mut c)?; // r
        read_f64_array12(&mut c)?; // p
        c.read_u32()?; // binning_x
        c.read_u32()?; // binning_y
        RegionOfInterest::read_cdr(&mut c)?;
        Ok(CameraInfo {
            offsets: [o0, o1, o2],
            buf,
        })
    }

    /// Returns a `Header` view (re-parses CDR prefix; prefer `stamp()`/`frame_id()`).
    pub fn header(&self) -> Header<&[u8]> {
        Header::from_cdr(self.buf.as_ref()).expect("header bytes validated during from_cdr")
    }
    pub fn stamp(&self) -> Time {
        rd_time(self.buf.as_ref(), CDR_HEADER_SIZE)
    }
    pub fn frame_id(&self) -> &str {
        rd_string(self.buf.as_ref(), CDR_HEADER_SIZE + 8).0
    }

    pub fn height(&self) -> u32 {
        rd_u32(self.buf.as_ref(), align(self.offsets[0], 4))
    }
    pub fn width(&self) -> u32 {
        rd_u32(self.buf.as_ref(), align(self.offsets[0], 4) + 4)
    }

    pub fn distortion_model(&self) -> &str {
        rd_string(self.buf.as_ref(), align(self.offsets[0], 4) + 8).0
    }

    /// Number of distortion coefficients.
    pub fn d_len(&self) -> usize {
        rd_u32(self.buf.as_ref(), align(self.offsets[1], 4)) as usize
    }

    /// Read the i-th distortion coefficient (zero-copy, on-demand).
    pub fn d_get(&self, i: usize) -> f64 {
        let start = cdr_align(align(self.offsets[1], 4) + 4, 8);
        rd_f64(self.buf.as_ref(), start + i * 8)
    }

    // Fixed region after d: k[9](72) + r[9](72) + p[12](96) + binning(8) + roi(17)
    fn fixed_base(&self) -> usize {
        cdr_align(self.offsets[2], 8)
    }

    pub fn k(&self) -> [f64; 9] {
        let mut c = CdrCursor::resume(self.buf.as_ref(), self.fixed_base());
        read_f64_array9(&mut c).expect("covariance field validated during from_cdr")
    }

    pub fn r(&self) -> [f64; 9] {
        let mut c = CdrCursor::resume(self.buf.as_ref(), self.fixed_base() + 72);
        read_f64_array9(&mut c).expect("covariance field validated during from_cdr")
    }

    pub fn p(&self) -> [f64; 12] {
        let mut c = CdrCursor::resume(self.buf.as_ref(), self.fixed_base() + 144);
        read_f64_array12(&mut c).expect("projection matrix validated during from_cdr")
    }

    pub fn binning_x(&self) -> u32 {
        rd_u32(self.buf.as_ref(), self.fixed_base() + 240)
    }
    pub fn binning_y(&self) -> u32 {
        rd_u32(self.buf.as_ref(), self.fixed_base() + 244)
    }

    pub fn roi(&self) -> RegionOfInterest {
        let mut c = CdrCursor::resume(self.buf.as_ref(), self.fixed_base() + 248);
        RegionOfInterest::read_cdr(&mut c).expect("roi field validated during from_cdr")
    }

    pub fn as_cdr(&self) -> &[u8] {
        self.buf.as_ref()
    }
    pub fn to_cdr(&self) -> Vec<u8> {
        self.buf.as_ref().to_vec()
    }
}

impl CameraInfo<Vec<u8>> {
    #[deprecated(
        since = "3.2.0",
        note = "use CameraInfo::builder() for allocation-free buffer reuse; CameraInfo::new will be removed in 4.0"
    )]
    #[allow(clippy::too_many_arguments)]
    pub fn new(
        stamp: Time,
        frame_id: &str,
        height: u32,
        width: u32,
        distortion_model: &str,
        d: &[f64],
        k: [f64; 9],
        r: [f64; 9],
        p: [f64; 12],
        binning_x: u32,
        binning_y: u32,
        roi: RegionOfInterest,
    ) -> Result<Self, CdrError> {
        let mut sizer = CdrSizer::new();
        Time::size_cdr(&mut sizer);
        sizer.size_string(frame_id);
        let o0 = sizer.offset();
        sizer.size_u32(); // height
        sizer.size_u32(); // width
        sizer.size_string(distortion_model);
        let o1 = sizer.offset();
        sizer.size_u32();
        sizer.size_seq_8(d.len());
        let o2 = sizer.offset();
        size_f64_array9(&mut sizer);
        size_f64_array9(&mut sizer);
        size_f64_array12(&mut sizer);
        sizer.size_u32(); // binning_x
        sizer.size_u32(); // binning_y
        RegionOfInterest::size_cdr(&mut sizer);

        let mut buf = vec![0u8; sizer.size()];
        let mut w = CdrWriter::new(&mut buf)?;
        stamp.write_cdr(&mut w);
        w.write_string(frame_id);
        w.write_u32(height);
        w.write_u32(width);
        w.write_string(distortion_model);
        w.write_u32(d.len() as u32);
        w.write_slice_f64(d);
        write_f64_array9(&mut w, &k);
        write_f64_array9(&mut w, &r);
        write_f64_array12(&mut w, &p);
        w.write_u32(binning_x);
        w.write_u32(binning_y);
        roi.write_cdr(&mut w);
        w.finish()?;

        Ok(CameraInfo {
            offsets: [o0, o1, o2],
            buf,
        })
    }

    pub fn into_cdr(self) -> Vec<u8> {
        self.buf
    }

    /// Start a new `CameraInfoBuilder` with zero-valued defaults.
    pub fn builder<'a>() -> CameraInfoBuilder<'a> {
        CameraInfoBuilder::new()
    }
}

// ── CameraInfoBuilder<'a> ───────────────────────────────────────────

/// Builder for `CameraInfo<Vec<u8>>` with buffer-reuse finalizers.
///
/// `d` is borrowed for zero-copy input. `k`, `r`, `p` are fixed-size
/// arrays stored by value. All other fields are owned/copied.
pub struct CameraInfoBuilder<'a> {
    stamp: Time,
    frame_id: std::borrow::Cow<'a, str>,
    height: u32,
    width: u32,
    distortion_model: std::borrow::Cow<'a, str>,
    d: &'a [f64],
    k: [f64; 9],
    r: [f64; 9],
    p: [f64; 12],
    binning_x: u32,
    binning_y: u32,
    roi: RegionOfInterest,
}

impl<'a> Default for CameraInfoBuilder<'a> {
    fn default() -> Self {
        Self {
            stamp: Time { sec: 0, nanosec: 0 },
            frame_id: std::borrow::Cow::Borrowed(""),
            height: 0,
            width: 0,
            distortion_model: std::borrow::Cow::Borrowed(""),
            d: &[],
            k: [0.0; 9],
            r: [0.0; 9],
            p: [0.0; 12],
            binning_x: 0,
            binning_y: 0,
            roi: RegionOfInterest {
                x_offset: 0,
                y_offset: 0,
                height: 0,
                width: 0,
                do_rectify: false,
            },
        }
    }
}

impl<'a> CameraInfoBuilder<'a> {
    pub fn new() -> Self {
        Self::default()
    }

    pub fn stamp(&mut self, t: Time) -> &mut Self {
        self.stamp = t;
        self
    }
    pub fn frame_id(&mut self, s: impl Into<std::borrow::Cow<'a, str>>) -> &mut Self {
        self.frame_id = s.into();
        self
    }
    pub fn height(&mut self, v: u32) -> &mut Self {
        self.height = v;
        self
    }
    pub fn width(&mut self, v: u32) -> &mut Self {
        self.width = v;
        self
    }
    pub fn distortion_model(&mut self, s: impl Into<std::borrow::Cow<'a, str>>) -> &mut Self {
        self.distortion_model = s.into();
        self
    }
    pub fn d(&mut self, d: &'a [f64]) -> &mut Self {
        self.d = d;
        self
    }
    pub fn k(&mut self, k: [f64; 9]) -> &mut Self {
        self.k = k;
        self
    }
    pub fn r(&mut self, r: [f64; 9]) -> &mut Self {
        self.r = r;
        self
    }
    pub fn p(&mut self, p: [f64; 12]) -> &mut Self {
        self.p = p;
        self
    }
    pub fn binning_x(&mut self, v: u32) -> &mut Self {
        self.binning_x = v;
        self
    }
    pub fn binning_y(&mut self, v: u32) -> &mut Self {
        self.binning_y = v;
        self
    }
    pub fn roi(&mut self, r: RegionOfInterest) -> &mut Self {
        self.roi = r;
        self
    }

    fn size(&self) -> usize {
        let mut s = CdrSizer::new();
        Time::size_cdr(&mut s);
        s.size_string(&self.frame_id);
        s.size_u32(); // height
        s.size_u32(); // width
        s.size_string(&self.distortion_model);
        s.size_u32();
        s.size_seq_8(self.d.len());
        size_f64_array9(&mut s);
        size_f64_array9(&mut s);
        size_f64_array12(&mut s);
        s.size_u32(); // binning_x
        s.size_u32(); // binning_y
        RegionOfInterest::size_cdr(&mut s);
        s.size()
    }

    fn write_into(&self, buf: &mut [u8]) -> Result<(), CdrError> {
        let mut w = CdrWriter::new(buf)?;
        self.stamp.write_cdr(&mut w);
        w.write_string(&self.frame_id);
        w.write_u32(self.height);
        w.write_u32(self.width);
        w.write_string(&self.distortion_model);
        w.write_u32(self.d.len() as u32);
        w.write_slice_f64(self.d);
        write_f64_array9(&mut w, &self.k);
        write_f64_array9(&mut w, &self.r);
        write_f64_array12(&mut w, &self.p);
        w.write_u32(self.binning_x);
        w.write_u32(self.binning_y);
        self.roi.write_cdr(&mut w);
        w.finish()
    }

    pub fn build(&self) -> Result<CameraInfo<Vec<u8>>, CdrError> {
        let mut buf = vec![0u8; self.size()];
        self.write_into(&mut buf)?;
        CameraInfo::from_cdr(buf)
    }

    pub fn encode_into_vec(&self, buf: &mut Vec<u8>) -> Result<(), CdrError> {
        buf.resize(self.size(), 0);
        self.write_into(buf)
    }

    pub fn encode_into_slice(&self, buf: &mut [u8]) -> Result<usize, CdrError> {
        let need = self.size();
        if buf.len() < need {
            return Err(CdrError::BufferTooShort {
                need,
                have: buf.len(),
            });
        }
        self.write_into(&mut buf[..need])?;
        Ok(need)
    }
}

impl<B: AsRef<[u8]> + AsMut<[u8]>> CameraInfo<B> {
    pub fn set_stamp(&mut self, t: Time) -> Result<(), CdrError> {
        let b = self.buf.as_mut();
        wr_i32(b, CDR_HEADER_SIZE, t.sec)?;
        wr_u32(b, CDR_HEADER_SIZE + 4, t.nanosec)
    }

    pub fn set_height(&mut self, h: u32) -> Result<(), CdrError> {
        let p = align(self.offsets[0], 4);
        wr_u32(self.buf.as_mut(), p, h)
    }

    pub fn set_width(&mut self, w: u32) -> Result<(), CdrError> {
        let p = align(self.offsets[0], 4) + 4;
        wr_u32(self.buf.as_mut(), p, w)
    }

    pub fn set_k(&mut self, k: [f64; 9]) -> Result<(), CdrError> {
        let p = self.fixed_base();
        let b = self.buf.as_mut();
        for (i, v) in k.iter().enumerate() {
            wr_f64(b, p + i * 8, *v)?;
        }
        Ok(())
    }

    pub fn set_r(&mut self, r: [f64; 9]) -> Result<(), CdrError> {
        let p = self.fixed_base() + 72;
        let b = self.buf.as_mut();
        for (i, v) in r.iter().enumerate() {
            wr_f64(b, p + i * 8, *v)?;
        }
        Ok(())
    }

    pub fn set_p(&mut self, p_mat: [f64; 12]) -> Result<(), CdrError> {
        let p = self.fixed_base() + 144;
        let b = self.buf.as_mut();
        for (i, v) in p_mat.iter().enumerate() {
            wr_f64(b, p + i * 8, *v)?;
        }
        Ok(())
    }

    pub fn set_binning_x(&mut self, v: u32) -> Result<(), CdrError> {
        let p = self.fixed_base() + 240;
        wr_u32(self.buf.as_mut(), p, v)
    }

    pub fn set_binning_y(&mut self, v: u32) -> Result<(), CdrError> {
        let p = self.fixed_base() + 244;
        wr_u32(self.buf.as_mut(), p, v)
    }

    pub fn set_roi(&mut self, r: RegionOfInterest) -> Result<(), CdrError> {
        let p = self.fixed_base() + 248;
        let b = self.buf.as_mut();
        wr_u32(b, p, r.x_offset)?;
        wr_u32(b, p + 4, r.y_offset)?;
        wr_u32(b, p + 8, r.height)?;
        wr_u32(b, p + 12, r.width)?;
        wr_bool(b, p + 16, r.do_rectify)
    }
}

// ── Constants ───────────────────────────────────────────────────────

pub mod nav_sat_fix {
    pub const COVARIANCE_TYPE_UNKNOWN: u8 = 0;
    pub const COVARIANCE_TYPE_APPROXIMATED: u8 = 1;
    pub const COVARIANCE_TYPE_DIAGONAL_KNOWN: u8 = 2;
    pub const COVARIANCE_TYPE_KNOWN: u8 = 3;
}

pub mod nav_sat_status {
    pub const STATUS_NO_FIX: i8 = -1;
    pub const STATUS_FIX: i8 = 0;
    pub const STATUS_SBAS_FIX: i8 = 1;
    pub const STATUS_GBAS_FIX: i8 = 2;
    pub const SERVICE_GPS: u8 = 1;
    pub const SERVICE_GLONASS: u8 = 2;
    pub const SERVICE_COMPASS: u8 = 4;
    pub const SERVICE_GALILEO: u8 = 8;
}

pub mod point_field {
    pub const INT8: u8 = 1;
    pub const UINT8: u8 = 2;
    pub const INT16: u8 = 3;
    pub const UINT16: u8 = 4;
    pub const INT32: u8 = 5;
    pub const UINT32: u8 = 6;
    pub const FLOAT32: u8 = 7;
    pub const FLOAT64: u8 = 8;
}

// ── MagneticField<B> ────────────────────────────────────────────────
//
// CDR layout: Header → offsets[0] (start of magnetic_field, 8-aligned),
//   Vector3 magnetic_field (24 bytes), float64[9] covariance (72 bytes).
// offsets[0] is captured from the cursor after Header+align(8) to avoid
// the EDGEAI-1243 class of bug.

pub struct MagneticField<B> {
    buf: B,
    offsets: [usize; 1],
}

impl<B: AsRef<[u8]>> MagneticField<B> {
    pub fn from_cdr(buf: B) -> Result<Self, CdrError> {
        let header = Header::<&[u8]>::from_cdr(buf.as_ref())?;
        let pre = header.end_offset();
        let mut c = CdrCursor::resume(buf.as_ref(), pre);
        c.align(8);
        let o0 = c.offset();
        Vector3::read_cdr(&mut c)?;
        read_f64_array9(&mut c)?;
        Ok(MagneticField { offsets: [o0], buf })
    }

    /// Returns a `Header` view by re-parsing the CDR buffer prefix.
    pub fn header(&self) -> Header<&[u8]> {
        Header::from_cdr(self.buf.as_ref()).expect("header bytes validated during from_cdr")
    }
    pub fn stamp(&self) -> Time {
        rd_time(self.buf.as_ref(), CDR_HEADER_SIZE)
    }
    pub fn frame_id(&self) -> &str {
        rd_string(self.buf.as_ref(), CDR_HEADER_SIZE + 8).0
    }
    pub fn magnetic_field(&self) -> Vector3 {
        let mut c = CdrCursor::resume(self.buf.as_ref(), self.offsets[0]);
        Vector3::read_cdr(&mut c).expect("magnetic_field validated during from_cdr")
    }
    pub fn magnetic_field_covariance(&self) -> [f64; 9] {
        let mut c = CdrCursor::resume(self.buf.as_ref(), self.offsets[0] + 24);
        read_f64_array9(&mut c).expect("covariance validated during from_cdr")
    }
    pub fn as_cdr(&self) -> &[u8] {
        self.buf.as_ref()
    }
    pub fn to_cdr(&self) -> Vec<u8> {
        self.buf.as_ref().to_vec()
    }
}

impl MagneticField<Vec<u8>> {
    #[deprecated(
        since = "3.2.0",
        note = "use MagneticField::builder() for allocation-free buffer reuse; MagneticField::new will be removed in 4.0"
    )]
    pub fn new(
        stamp: Time,
        frame_id: &str,
        magnetic_field: Vector3,
        magnetic_field_covariance: [f64; 9],
    ) -> Result<Self, CdrError> {
        let mut sizer = CdrSizer::new();
        Time::size_cdr(&mut sizer);
        sizer.size_string(frame_id);
        sizer.align(8);
        let o0 = sizer.offset();
        Vector3::size_cdr(&mut sizer);
        size_f64_array9(&mut sizer);

        let mut buf = vec![0u8; sizer.size()];
        let mut w = CdrWriter::new(&mut buf)?;
        stamp.write_cdr(&mut w);
        w.write_string(frame_id);
        magnetic_field.write_cdr(&mut w);
        write_f64_array9(&mut w, &magnetic_field_covariance);
        w.finish()?;

        Ok(MagneticField { offsets: [o0], buf })
    }

    pub fn into_cdr(self) -> Vec<u8> {
        self.buf
    }

    /// Start a new `MagneticFieldBuilder` with zero-valued defaults.
    pub fn builder<'a>() -> MagneticFieldBuilder<'a> {
        MagneticFieldBuilder::new()
    }
}

// ── MagneticFieldBuilder<'a> ────────────────────────────────────────

/// Builder for `MagneticField<Vec<u8>>` with buffer-reuse finalizers.
pub struct MagneticFieldBuilder<'a> {
    stamp: Time,
    frame_id: std::borrow::Cow<'a, str>,
    magnetic_field: Vector3,
    magnetic_field_covariance: [f64; 9],
}

impl<'a> Default for MagneticFieldBuilder<'a> {
    fn default() -> Self {
        Self {
            stamp: Time { sec: 0, nanosec: 0 },
            frame_id: std::borrow::Cow::Borrowed(""),
            magnetic_field: Vector3 {
                x: 0.0,
                y: 0.0,
                z: 0.0,
            },
            magnetic_field_covariance: [0.0; 9],
        }
    }
}

impl<'a> MagneticFieldBuilder<'a> {
    pub fn new() -> Self {
        Self::default()
    }

    pub fn stamp(&mut self, t: Time) -> &mut Self {
        self.stamp = t;
        self
    }
    pub fn frame_id(&mut self, s: impl Into<std::borrow::Cow<'a, str>>) -> &mut Self {
        self.frame_id = s.into();
        self
    }
    pub fn magnetic_field(&mut self, v: Vector3) -> &mut Self {
        self.magnetic_field = v;
        self
    }
    pub fn magnetic_field_covariance(&mut self, c: [f64; 9]) -> &mut Self {
        self.magnetic_field_covariance = c;
        self
    }

    fn size(&self) -> usize {
        let mut s = CdrSizer::new();
        Time::size_cdr(&mut s);
        s.size_string(&self.frame_id);
        s.align(8);
        Vector3::size_cdr(&mut s);
        size_f64_array9(&mut s);
        s.size()
    }

    fn write_into(&self, buf: &mut [u8]) -> Result<(), CdrError> {
        let mut w = CdrWriter::new(buf)?;
        self.stamp.write_cdr(&mut w);
        w.write_string(&self.frame_id);
        self.magnetic_field.write_cdr(&mut w);
        write_f64_array9(&mut w, &self.magnetic_field_covariance);
        w.finish()
    }

    pub fn build(&self) -> Result<MagneticField<Vec<u8>>, CdrError> {
        let mut buf = vec![0u8; self.size()];
        self.write_into(&mut buf)?;
        MagneticField::from_cdr(buf)
    }

    pub fn encode_into_vec(&self, buf: &mut Vec<u8>) -> Result<(), CdrError> {
        buf.resize(self.size(), 0);
        self.write_into(buf)
    }

    pub fn encode_into_slice(&self, buf: &mut [u8]) -> Result<usize, CdrError> {
        let need = self.size();
        if buf.len() < need {
            return Err(CdrError::BufferTooShort {
                need,
                have: buf.len(),
            });
        }
        self.write_into(&mut buf[..need])?;
        Ok(need)
    }
}

impl<B: AsRef<[u8]> + AsMut<[u8]>> MagneticField<B> {
    pub fn set_stamp(&mut self, t: Time) -> Result<(), CdrError> {
        let b = self.buf.as_mut();
        wr_i32(b, CDR_HEADER_SIZE, t.sec)?;
        wr_u32(b, CDR_HEADER_SIZE + 4, t.nanosec)
    }

    pub fn set_magnetic_field(&mut self, v: Vector3) -> Result<(), CdrError> {
        let p = self.offsets[0];
        let b = self.buf.as_mut();
        wr_f64(b, p, v.x)?;
        wr_f64(b, p + 8, v.y)?;
        wr_f64(b, p + 16, v.z)
    }

    pub fn set_magnetic_field_covariance(&mut self, c: [f64; 9]) -> Result<(), CdrError> {
        let p = self.offsets[0] + 24;
        let b = self.buf.as_mut();
        for (i, v) in c.iter().enumerate() {
            wr_f64(b, p + i * 8, *v)?;
        }
        Ok(())
    }
}

// ── FluidPressure<B> ────────────────────────────────────────────────
//
// CDR layout: Header → offsets[0] (start of fluid_pressure, 8-aligned),
//   float64 fluid_pressure (8 bytes), float64 variance (8 bytes).

pub struct FluidPressure<B> {
    buf: B,
    offsets: [usize; 1],
}

impl<B: AsRef<[u8]>> FluidPressure<B> {
    pub fn from_cdr(buf: B) -> Result<Self, CdrError> {
        let header = Header::<&[u8]>::from_cdr(buf.as_ref())?;
        let pre = header.end_offset();
        let mut c = CdrCursor::resume(buf.as_ref(), pre);
        c.align(8);
        let o0 = c.offset();
        c.read_f64()?; // fluid_pressure
        c.read_f64()?; // variance
        Ok(FluidPressure { offsets: [o0], buf })
    }

    pub fn header(&self) -> Header<&[u8]> {
        Header::from_cdr(self.buf.as_ref()).expect("header bytes validated during from_cdr")
    }
    pub fn stamp(&self) -> Time {
        rd_time(self.buf.as_ref(), CDR_HEADER_SIZE)
    }
    pub fn frame_id(&self) -> &str {
        rd_string(self.buf.as_ref(), CDR_HEADER_SIZE + 8).0
    }
    pub fn fluid_pressure(&self) -> f64 {
        rd_f64(self.buf.as_ref(), self.offsets[0])
    }
    pub fn variance(&self) -> f64 {
        rd_f64(self.buf.as_ref(), self.offsets[0] + 8)
    }
    pub fn as_cdr(&self) -> &[u8] {
        self.buf.as_ref()
    }
    pub fn to_cdr(&self) -> Vec<u8> {
        self.buf.as_ref().to_vec()
    }
}

impl FluidPressure<Vec<u8>> {
    #[deprecated(
        since = "3.2.0",
        note = "use FluidPressure::builder() for allocation-free buffer reuse; FluidPressure::new will be removed in 4.0"
    )]
    pub fn new(
        stamp: Time,
        frame_id: &str,
        fluid_pressure: f64,
        variance: f64,
    ) -> Result<Self, CdrError> {
        let mut sizer = CdrSizer::new();
        Time::size_cdr(&mut sizer);
        sizer.size_string(frame_id);
        sizer.align(8);
        let o0 = sizer.offset();
        sizer.size_f64();
        sizer.size_f64();

        let mut buf = vec![0u8; sizer.size()];
        let mut w = CdrWriter::new(&mut buf)?;
        stamp.write_cdr(&mut w);
        w.write_string(frame_id);
        w.write_f64(fluid_pressure);
        w.write_f64(variance);
        w.finish()?;

        Ok(FluidPressure { offsets: [o0], buf })
    }

    pub fn into_cdr(self) -> Vec<u8> {
        self.buf
    }

    /// Start a new `FluidPressureBuilder` with zero-valued defaults.
    pub fn builder<'a>() -> FluidPressureBuilder<'a> {
        FluidPressureBuilder::new()
    }
}

// ── FluidPressureBuilder<'a> ────────────────────────────────────────

/// Builder for `FluidPressure<Vec<u8>>` with buffer-reuse finalizers.
pub struct FluidPressureBuilder<'a> {
    stamp: Time,
    frame_id: std::borrow::Cow<'a, str>,
    fluid_pressure: f64,
    variance: f64,
}

impl<'a> Default for FluidPressureBuilder<'a> {
    fn default() -> Self {
        Self {
            stamp: Time { sec: 0, nanosec: 0 },
            frame_id: std::borrow::Cow::Borrowed(""),
            fluid_pressure: 0.0,
            variance: 0.0,
        }
    }
}

impl<'a> FluidPressureBuilder<'a> {
    pub fn new() -> Self {
        Self::default()
    }

    pub fn stamp(&mut self, t: Time) -> &mut Self {
        self.stamp = t;
        self
    }
    pub fn frame_id(&mut self, s: impl Into<std::borrow::Cow<'a, str>>) -> &mut Self {
        self.frame_id = s.into();
        self
    }
    pub fn fluid_pressure(&mut self, v: f64) -> &mut Self {
        self.fluid_pressure = v;
        self
    }
    pub fn variance(&mut self, v: f64) -> &mut Self {
        self.variance = v;
        self
    }

    fn size(&self) -> usize {
        let mut s = CdrSizer::new();
        Time::size_cdr(&mut s);
        s.size_string(&self.frame_id);
        s.align(8);
        s.size_f64();
        s.size_f64();
        s.size()
    }

    fn write_into(&self, buf: &mut [u8]) -> Result<(), CdrError> {
        let mut w = CdrWriter::new(buf)?;
        self.stamp.write_cdr(&mut w);
        w.write_string(&self.frame_id);
        w.write_f64(self.fluid_pressure);
        w.write_f64(self.variance);
        w.finish()
    }

    pub fn build(&self) -> Result<FluidPressure<Vec<u8>>, CdrError> {
        let mut buf = vec![0u8; self.size()];
        self.write_into(&mut buf)?;
        FluidPressure::from_cdr(buf)
    }

    pub fn encode_into_vec(&self, buf: &mut Vec<u8>) -> Result<(), CdrError> {
        buf.resize(self.size(), 0);
        self.write_into(buf)
    }

    pub fn encode_into_slice(&self, buf: &mut [u8]) -> Result<usize, CdrError> {
        let need = self.size();
        if buf.len() < need {
            return Err(CdrError::BufferTooShort {
                need,
                have: buf.len(),
            });
        }
        self.write_into(&mut buf[..need])?;
        Ok(need)
    }
}

impl<B: AsRef<[u8]> + AsMut<[u8]>> FluidPressure<B> {
    pub fn set_stamp(&mut self, t: Time) -> Result<(), CdrError> {
        let b = self.buf.as_mut();
        wr_i32(b, CDR_HEADER_SIZE, t.sec)?;
        wr_u32(b, CDR_HEADER_SIZE + 4, t.nanosec)
    }

    pub fn set_fluid_pressure(&mut self, v: f64) -> Result<(), CdrError> {
        wr_f64(self.buf.as_mut(), self.offsets[0], v)
    }

    pub fn set_variance(&mut self, v: f64) -> Result<(), CdrError> {
        wr_f64(self.buf.as_mut(), self.offsets[0] + 8, v)
    }
}

// ── Temperature<B> ──────────────────────────────────────────────────
//
// CDR layout: Header → offsets[0] (start of temperature, 8-aligned),
//   float64 temperature (8 bytes), float64 variance (8 bytes).

pub struct Temperature<B> {
    buf: B,
    offsets: [usize; 1],
}

impl<B: AsRef<[u8]>> Temperature<B> {
    pub fn from_cdr(buf: B) -> Result<Self, CdrError> {
        let header = Header::<&[u8]>::from_cdr(buf.as_ref())?;
        let pre = header.end_offset();
        let mut c = CdrCursor::resume(buf.as_ref(), pre);
        c.align(8);
        let o0 = c.offset();
        c.read_f64()?; // temperature
        c.read_f64()?; // variance
        Ok(Temperature { offsets: [o0], buf })
    }

    pub fn header(&self) -> Header<&[u8]> {
        Header::from_cdr(self.buf.as_ref()).expect("header bytes validated during from_cdr")
    }
    pub fn stamp(&self) -> Time {
        rd_time(self.buf.as_ref(), CDR_HEADER_SIZE)
    }
    pub fn frame_id(&self) -> &str {
        rd_string(self.buf.as_ref(), CDR_HEADER_SIZE + 8).0
    }
    pub fn temperature(&self) -> f64 {
        rd_f64(self.buf.as_ref(), self.offsets[0])
    }
    pub fn variance(&self) -> f64 {
        rd_f64(self.buf.as_ref(), self.offsets[0] + 8)
    }
    pub fn as_cdr(&self) -> &[u8] {
        self.buf.as_ref()
    }
    pub fn to_cdr(&self) -> Vec<u8> {
        self.buf.as_ref().to_vec()
    }
}

impl Temperature<Vec<u8>> {
    #[deprecated(
        since = "3.2.0",
        note = "use Temperature::builder() for allocation-free buffer reuse; Temperature::new will be removed in 4.0"
    )]
    pub fn new(
        stamp: Time,
        frame_id: &str,
        temperature: f64,
        variance: f64,
    ) -> Result<Self, CdrError> {
        let mut sizer = CdrSizer::new();
        Time::size_cdr(&mut sizer);
        sizer.size_string(frame_id);
        sizer.align(8);
        let o0 = sizer.offset();
        sizer.size_f64();
        sizer.size_f64();

        let mut buf = vec![0u8; sizer.size()];
        let mut w = CdrWriter::new(&mut buf)?;
        stamp.write_cdr(&mut w);
        w.write_string(frame_id);
        w.write_f64(temperature);
        w.write_f64(variance);
        w.finish()?;

        Ok(Temperature { offsets: [o0], buf })
    }

    pub fn into_cdr(self) -> Vec<u8> {
        self.buf
    }

    /// Start a new `TemperatureBuilder` with zero-valued defaults.
    pub fn builder<'a>() -> TemperatureBuilder<'a> {
        TemperatureBuilder::new()
    }
}

// ── TemperatureBuilder<'a> ──────────────────────────────────────────

/// Builder for `Temperature<Vec<u8>>` with buffer-reuse finalizers.
pub struct TemperatureBuilder<'a> {
    stamp: Time,
    frame_id: std::borrow::Cow<'a, str>,
    temperature: f64,
    variance: f64,
}

impl<'a> Default for TemperatureBuilder<'a> {
    fn default() -> Self {
        Self {
            stamp: Time { sec: 0, nanosec: 0 },
            frame_id: std::borrow::Cow::Borrowed(""),
            temperature: 0.0,
            variance: 0.0,
        }
    }
}

impl<'a> TemperatureBuilder<'a> {
    pub fn new() -> Self {
        Self::default()
    }

    pub fn stamp(&mut self, t: Time) -> &mut Self {
        self.stamp = t;
        self
    }
    pub fn frame_id(&mut self, s: impl Into<std::borrow::Cow<'a, str>>) -> &mut Self {
        self.frame_id = s.into();
        self
    }
    pub fn temperature(&mut self, v: f64) -> &mut Self {
        self.temperature = v;
        self
    }
    pub fn variance(&mut self, v: f64) -> &mut Self {
        self.variance = v;
        self
    }

    fn size(&self) -> usize {
        let mut s = CdrSizer::new();
        Time::size_cdr(&mut s);
        s.size_string(&self.frame_id);
        s.align(8);
        s.size_f64();
        s.size_f64();
        s.size()
    }

    fn write_into(&self, buf: &mut [u8]) -> Result<(), CdrError> {
        let mut w = CdrWriter::new(buf)?;
        self.stamp.write_cdr(&mut w);
        w.write_string(&self.frame_id);
        w.write_f64(self.temperature);
        w.write_f64(self.variance);
        w.finish()
    }

    pub fn build(&self) -> Result<Temperature<Vec<u8>>, CdrError> {
        let mut buf = vec![0u8; self.size()];
        self.write_into(&mut buf)?;
        Temperature::from_cdr(buf)
    }

    pub fn encode_into_vec(&self, buf: &mut Vec<u8>) -> Result<(), CdrError> {
        buf.resize(self.size(), 0);
        self.write_into(buf)
    }

    pub fn encode_into_slice(&self, buf: &mut [u8]) -> Result<usize, CdrError> {
        let need = self.size();
        if buf.len() < need {
            return Err(CdrError::BufferTooShort {
                need,
                have: buf.len(),
            });
        }
        self.write_into(&mut buf[..need])?;
        Ok(need)
    }
}

impl<B: AsRef<[u8]> + AsMut<[u8]>> Temperature<B> {
    pub fn set_stamp(&mut self, t: Time) -> Result<(), CdrError> {
        let b = self.buf.as_mut();
        wr_i32(b, CDR_HEADER_SIZE, t.sec)?;
        wr_u32(b, CDR_HEADER_SIZE + 4, t.nanosec)
    }

    pub fn set_temperature(&mut self, v: f64) -> Result<(), CdrError> {
        wr_f64(self.buf.as_mut(), self.offsets[0], v)
    }

    pub fn set_variance(&mut self, v: f64) -> Result<(), CdrError> {
        wr_f64(self.buf.as_mut(), self.offsets[0] + 8, v)
    }
}

// ── BatteryState<B> ─────────────────────────────────────────────────
//
// CDR layout: Header → offsets[0] (start of fixed scalars, 4-aligned),
//   float32 voltage, temperature, current, charge, capacity,
//   design_capacity, percentage (7×4 = 28 bytes),
//   uint8 power_supply_status, power_supply_health,
//   power_supply_technology, bool present (4 bytes, no trailing pad
//   until next 4-aligned field),
//   uint32 count + float32[] cell_voltage → offsets[1] (byte index of
//     the seq count u32),
//   uint32 count + float32[] cell_temperature → offsets[2],
//   string location → offsets[3],
//   string serial_number → offsets[4].

/// `POWER_SUPPLY_STATUS_*` values for [`BatteryState::power_supply_status`].
pub mod power_supply_status {
    pub const UNKNOWN: u8 = 0;
    pub const CHARGING: u8 = 1;
    pub const DISCHARGING: u8 = 2;
    pub const NOT_CHARGING: u8 = 3;
    pub const FULL: u8 = 4;
}

/// `POWER_SUPPLY_HEALTH_*` values for [`BatteryState::power_supply_health`].
pub mod power_supply_health {
    pub const UNKNOWN: u8 = 0;
    pub const GOOD: u8 = 1;
    pub const OVERHEAT: u8 = 2;
    pub const DEAD: u8 = 3;
    pub const OVERVOLTAGE: u8 = 4;
    pub const UNSPEC_FAILURE: u8 = 5;
    pub const COLD: u8 = 6;
    pub const WATCHDOG_TIMER_EXPIRE: u8 = 7;
    pub const SAFETY_TIMER_EXPIRE: u8 = 8;
}

/// `POWER_SUPPLY_TECHNOLOGY_*` values for [`BatteryState::power_supply_technology`].
pub mod power_supply_technology {
    pub const UNKNOWN: u8 = 0;
    pub const NIMH: u8 = 1;
    pub const LION: u8 = 2;
    pub const LIPO: u8 = 3;
    pub const LIFE: u8 = 4;
    pub const NICD: u8 = 5;
    pub const LIMN: u8 = 6;
}

pub struct BatteryState<B> {
    buf: B,
    // [0]: voltage start (4-aligned after Header).
    // [1]: start of cell_voltage seq-count u32.
    // [2]: start of cell_temperature seq-count u32.
    // [3]: start of location string.
    // [4]: start of serial_number string.
    offsets: [usize; 5],
}

impl<B: AsRef<[u8]>> BatteryState<B> {
    pub fn from_cdr(buf: B) -> Result<Self, CdrError> {
        let header = Header::<&[u8]>::from_cdr(buf.as_ref())?;
        let pre = header.end_offset();
        let mut c = CdrCursor::resume(buf.as_ref(), pre);
        c.align(4);
        let o0 = c.offset();
        // Seven f32 scalars
        for _ in 0..7 {
            c.read_f32()?;
        }
        c.read_u8()?; // power_supply_status
        c.read_u8()?; // power_supply_health
        c.read_u8()?; // power_supply_technology
        c.read_bool()?; // present
        let o1 = c.offset();
        // f32 = 4 bytes each; hardening check against pathological counts.
        let raw = c.read_u32()?;
        let cv_len = c.check_seq_count(raw, 4)?;
        for _ in 0..cv_len {
            c.read_f32()?;
        }
        let o2 = c.offset();
        let raw = c.read_u32()?;
        let ct_len = c.check_seq_count(raw, 4)?;
        for _ in 0..ct_len {
            c.read_f32()?;
        }
        let o3 = c.offset();
        c.read_string()?; // location
        let o4 = c.offset();
        c.read_string()?; // serial_number
        Ok(BatteryState {
            offsets: [o0, o1, o2, o3, o4],
            buf,
        })
    }

    pub fn header(&self) -> Header<&[u8]> {
        Header::from_cdr(self.buf.as_ref()).expect("header bytes validated during from_cdr")
    }
    pub fn stamp(&self) -> Time {
        rd_time(self.buf.as_ref(), CDR_HEADER_SIZE)
    }
    pub fn frame_id(&self) -> &str {
        rd_string(self.buf.as_ref(), CDR_HEADER_SIZE + 8).0
    }
    pub fn voltage(&self) -> f32 {
        rd_f32(self.buf.as_ref(), self.offsets[0])
    }
    pub fn temperature(&self) -> f32 {
        rd_f32(self.buf.as_ref(), self.offsets[0] + 4)
    }
    pub fn current(&self) -> f32 {
        rd_f32(self.buf.as_ref(), self.offsets[0] + 8)
    }
    pub fn charge(&self) -> f32 {
        rd_f32(self.buf.as_ref(), self.offsets[0] + 12)
    }
    pub fn capacity(&self) -> f32 {
        rd_f32(self.buf.as_ref(), self.offsets[0] + 16)
    }
    pub fn design_capacity(&self) -> f32 {
        rd_f32(self.buf.as_ref(), self.offsets[0] + 20)
    }
    pub fn percentage(&self) -> f32 {
        rd_f32(self.buf.as_ref(), self.offsets[0] + 24)
    }
    pub fn power_supply_status(&self) -> u8 {
        rd_u8(self.buf.as_ref(), self.offsets[0] + 28)
    }
    pub fn power_supply_health(&self) -> u8 {
        rd_u8(self.buf.as_ref(), self.offsets[0] + 29)
    }
    pub fn power_supply_technology(&self) -> u8 {
        rd_u8(self.buf.as_ref(), self.offsets[0] + 30)
    }
    pub fn present(&self) -> bool {
        rd_bool(self.buf.as_ref(), self.offsets[0] + 31)
    }
    pub fn cell_voltage_len(&self) -> u32 {
        rd_u32(self.buf.as_ref(), self.offsets[1])
    }
    /// Byte offset of the `cell_voltage` sequence (u32 count, then elements).
    /// Exposed for allocation-free decoders (e.g. FFI).
    pub fn cell_voltage_seq_offset(&self) -> usize {
        self.offsets[1]
    }
    pub fn cell_voltage(&self) -> Vec<f32> {
        let mut c = CdrCursor::resume(self.buf.as_ref(), self.offsets[1]);
        let n = c
            .read_u32()
            .expect("cell_voltage length validated during from_cdr") as usize;
        let mut out = Vec::with_capacity(n);
        for _ in 0..n {
            out.push(
                c.read_f32()
                    .expect("cell_voltage element validated during from_cdr"),
            );
        }
        out
    }
    pub fn cell_temperature_len(&self) -> u32 {
        rd_u32(self.buf.as_ref(), self.offsets[2])
    }
    /// Byte offset of the `cell_temperature` sequence (u32 count, then elements).
    /// Exposed for allocation-free decoders (e.g. FFI).
    pub fn cell_temperature_seq_offset(&self) -> usize {
        self.offsets[2]
    }
    pub fn cell_temperature(&self) -> Vec<f32> {
        let mut c = CdrCursor::resume(self.buf.as_ref(), self.offsets[2]);
        let n = c
            .read_u32()
            .expect("cell_temperature length validated during from_cdr") as usize;
        let mut out = Vec::with_capacity(n);
        for _ in 0..n {
            out.push(
                c.read_f32()
                    .expect("cell_temperature element validated during from_cdr"),
            );
        }
        out
    }
    pub fn location(&self) -> &str {
        rd_string(self.buf.as_ref(), self.offsets[3]).0
    }
    pub fn serial_number(&self) -> &str {
        rd_string(self.buf.as_ref(), self.offsets[4]).0
    }
    pub fn as_cdr(&self) -> &[u8] {
        self.buf.as_ref()
    }
    pub fn to_cdr(&self) -> Vec<u8> {
        self.buf.as_ref().to_vec()
    }
}

impl BatteryState<Vec<u8>> {
    #[deprecated(
        since = "3.2.0",
        note = "use BatteryState::builder() for allocation-free buffer reuse; BatteryState::new will be removed in 4.0"
    )]
    #[allow(clippy::too_many_arguments)]
    pub fn new(
        stamp: Time,
        frame_id: &str,
        voltage: f32,
        temperature: f32,
        current: f32,
        charge: f32,
        capacity: f32,
        design_capacity: f32,
        percentage: f32,
        power_supply_status: u8,
        power_supply_health: u8,
        power_supply_technology: u8,
        present: bool,
        cell_voltage: &[f32],
        cell_temperature: &[f32],
        location: &str,
        serial_number: &str,
    ) -> Result<Self, CdrError> {
        let mut sizer = CdrSizer::new();
        Time::size_cdr(&mut sizer);
        sizer.size_string(frame_id);
        sizer.align(4);
        let o0 = sizer.offset();
        for _ in 0..7 {
            sizer.size_f32();
        }
        sizer.size_u8();
        sizer.size_u8();
        sizer.size_u8();
        sizer.size_bool();
        let o1 = sizer.offset();
        sizer.size_u32();
        for _ in cell_voltage {
            sizer.size_f32();
        }
        let o2 = sizer.offset();
        sizer.size_u32();
        for _ in cell_temperature {
            sizer.size_f32();
        }
        let o3 = sizer.offset();
        sizer.size_string(location);
        let o4 = sizer.offset();
        sizer.size_string(serial_number);

        let mut buf = vec![0u8; sizer.size()];
        let mut w = CdrWriter::new(&mut buf)?;
        stamp.write_cdr(&mut w);
        w.write_string(frame_id);
        w.write_f32(voltage);
        w.write_f32(temperature);
        w.write_f32(current);
        w.write_f32(charge);
        w.write_f32(capacity);
        w.write_f32(design_capacity);
        w.write_f32(percentage);
        w.write_u8(power_supply_status);
        w.write_u8(power_supply_health);
        w.write_u8(power_supply_technology);
        w.write_bool(present);
        w.write_u32(cell_voltage.len() as u32);
        for v in cell_voltage {
            w.write_f32(*v);
        }
        w.write_u32(cell_temperature.len() as u32);
        for v in cell_temperature {
            w.write_f32(*v);
        }
        w.write_string(location);
        w.write_string(serial_number);
        w.finish()?;

        Ok(BatteryState {
            offsets: [o0, o1, o2, o3, o4],
            buf,
        })
    }

    pub fn into_cdr(self) -> Vec<u8> {
        self.buf
    }

    /// Start a new `BatteryStateBuilder` with zero-valued defaults.
    pub fn builder<'a>() -> BatteryStateBuilder<'a> {
        BatteryStateBuilder::new()
    }
}

// ── BatteryStateBuilder<'a> ─────────────────────────────────────────

/// Builder for `BatteryState<Vec<u8>>` with buffer-reuse finalizers.
///
/// The two `f32` sequences (`cell_voltage`, `cell_temperature`) are
/// borrowed for zero-copy input; both strings use `Cow<'a, str>`.
pub struct BatteryStateBuilder<'a> {
    stamp: Time,
    frame_id: std::borrow::Cow<'a, str>,
    voltage: f32,
    temperature: f32,
    current: f32,
    charge: f32,
    capacity: f32,
    design_capacity: f32,
    percentage: f32,
    power_supply_status: u8,
    power_supply_health: u8,
    power_supply_technology: u8,
    present: bool,
    cell_voltage: &'a [f32],
    cell_temperature: &'a [f32],
    location: std::borrow::Cow<'a, str>,
    serial_number: std::borrow::Cow<'a, str>,
}

impl<'a> Default for BatteryStateBuilder<'a> {
    fn default() -> Self {
        Self {
            stamp: Time { sec: 0, nanosec: 0 },
            frame_id: std::borrow::Cow::Borrowed(""),
            voltage: 0.0,
            temperature: 0.0,
            current: 0.0,
            charge: 0.0,
            capacity: 0.0,
            design_capacity: 0.0,
            percentage: 0.0,
            power_supply_status: 0,
            power_supply_health: 0,
            power_supply_technology: 0,
            present: false,
            cell_voltage: &[],
            cell_temperature: &[],
            location: std::borrow::Cow::Borrowed(""),
            serial_number: std::borrow::Cow::Borrowed(""),
        }
    }
}

impl<'a> BatteryStateBuilder<'a> {
    pub fn new() -> Self {
        Self::default()
    }

    pub fn stamp(&mut self, t: Time) -> &mut Self {
        self.stamp = t;
        self
    }
    pub fn frame_id(&mut self, s: impl Into<std::borrow::Cow<'a, str>>) -> &mut Self {
        self.frame_id = s.into();
        self
    }
    pub fn voltage(&mut self, v: f32) -> &mut Self {
        self.voltage = v;
        self
    }
    pub fn temperature(&mut self, v: f32) -> &mut Self {
        self.temperature = v;
        self
    }
    pub fn current(&mut self, v: f32) -> &mut Self {
        self.current = v;
        self
    }
    pub fn charge(&mut self, v: f32) -> &mut Self {
        self.charge = v;
        self
    }
    pub fn capacity(&mut self, v: f32) -> &mut Self {
        self.capacity = v;
        self
    }
    pub fn design_capacity(&mut self, v: f32) -> &mut Self {
        self.design_capacity = v;
        self
    }
    pub fn percentage(&mut self, v: f32) -> &mut Self {
        self.percentage = v;
        self
    }
    pub fn power_supply_status(&mut self, v: u8) -> &mut Self {
        self.power_supply_status = v;
        self
    }
    pub fn power_supply_health(&mut self, v: u8) -> &mut Self {
        self.power_supply_health = v;
        self
    }
    pub fn power_supply_technology(&mut self, v: u8) -> &mut Self {
        self.power_supply_technology = v;
        self
    }
    pub fn present(&mut self, v: bool) -> &mut Self {
        self.present = v;
        self
    }
    pub fn cell_voltage(&mut self, v: &'a [f32]) -> &mut Self {
        self.cell_voltage = v;
        self
    }
    pub fn cell_temperature(&mut self, v: &'a [f32]) -> &mut Self {
        self.cell_temperature = v;
        self
    }
    pub fn location(&mut self, s: impl Into<std::borrow::Cow<'a, str>>) -> &mut Self {
        self.location = s.into();
        self
    }
    pub fn serial_number(&mut self, s: impl Into<std::borrow::Cow<'a, str>>) -> &mut Self {
        self.serial_number = s.into();
        self
    }

    fn size(&self) -> usize {
        let mut s = CdrSizer::new();
        Time::size_cdr(&mut s);
        s.size_string(&self.frame_id);
        s.align(4);
        for _ in 0..7 {
            s.size_f32();
        }
        s.size_u8();
        s.size_u8();
        s.size_u8();
        s.size_bool();
        s.size_u32();
        for _ in self.cell_voltage {
            s.size_f32();
        }
        s.size_u32();
        for _ in self.cell_temperature {
            s.size_f32();
        }
        s.size_string(&self.location);
        s.size_string(&self.serial_number);
        s.size()
    }

    fn write_into(&self, buf: &mut [u8]) -> Result<(), CdrError> {
        let mut w = CdrWriter::new(buf)?;
        self.stamp.write_cdr(&mut w);
        w.write_string(&self.frame_id);
        w.write_f32(self.voltage);
        w.write_f32(self.temperature);
        w.write_f32(self.current);
        w.write_f32(self.charge);
        w.write_f32(self.capacity);
        w.write_f32(self.design_capacity);
        w.write_f32(self.percentage);
        w.write_u8(self.power_supply_status);
        w.write_u8(self.power_supply_health);
        w.write_u8(self.power_supply_technology);
        w.write_bool(self.present);
        w.write_u32(self.cell_voltage.len() as u32);
        for v in self.cell_voltage {
            w.write_f32(*v);
        }
        w.write_u32(self.cell_temperature.len() as u32);
        for v in self.cell_temperature {
            w.write_f32(*v);
        }
        w.write_string(&self.location);
        w.write_string(&self.serial_number);
        w.finish()
    }

    pub fn build(&self) -> Result<BatteryState<Vec<u8>>, CdrError> {
        let mut buf = vec![0u8; self.size()];
        self.write_into(&mut buf)?;
        BatteryState::from_cdr(buf)
    }

    pub fn encode_into_vec(&self, buf: &mut Vec<u8>) -> Result<(), CdrError> {
        buf.resize(self.size(), 0);
        self.write_into(buf)
    }

    pub fn encode_into_slice(&self, buf: &mut [u8]) -> Result<usize, CdrError> {
        let need = self.size();
        if buf.len() < need {
            return Err(CdrError::BufferTooShort {
                need,
                have: buf.len(),
            });
        }
        self.write_into(&mut buf[..need])?;
        Ok(need)
    }
}

impl<B: AsRef<[u8]> + AsMut<[u8]>> BatteryState<B> {
    pub fn set_stamp(&mut self, t: Time) -> Result<(), CdrError> {
        let b = self.buf.as_mut();
        wr_i32(b, CDR_HEADER_SIZE, t.sec)?;
        wr_u32(b, CDR_HEADER_SIZE + 4, t.nanosec)
    }

    pub fn set_voltage(&mut self, v: f32) -> Result<(), CdrError> {
        wr_f32(self.buf.as_mut(), self.offsets[0], v)
    }

    pub fn set_temperature(&mut self, v: f32) -> Result<(), CdrError> {
        wr_f32(self.buf.as_mut(), self.offsets[0] + 4, v)
    }

    pub fn set_current(&mut self, v: f32) -> Result<(), CdrError> {
        wr_f32(self.buf.as_mut(), self.offsets[0] + 8, v)
    }

    pub fn set_charge(&mut self, v: f32) -> Result<(), CdrError> {
        wr_f32(self.buf.as_mut(), self.offsets[0] + 12, v)
    }

    pub fn set_capacity(&mut self, v: f32) -> Result<(), CdrError> {
        wr_f32(self.buf.as_mut(), self.offsets[0] + 16, v)
    }

    pub fn set_design_capacity(&mut self, v: f32) -> Result<(), CdrError> {
        wr_f32(self.buf.as_mut(), self.offsets[0] + 20, v)
    }

    pub fn set_percentage(&mut self, v: f32) -> Result<(), CdrError> {
        wr_f32(self.buf.as_mut(), self.offsets[0] + 24, v)
    }

    pub fn set_power_supply_status(&mut self, v: u8) -> Result<(), CdrError> {
        wr_u8(self.buf.as_mut(), self.offsets[0] + 28, v)
    }

    pub fn set_power_supply_health(&mut self, v: u8) -> Result<(), CdrError> {
        wr_u8(self.buf.as_mut(), self.offsets[0] + 29, v)
    }

    pub fn set_power_supply_technology(&mut self, v: u8) -> Result<(), CdrError> {
        wr_u8(self.buf.as_mut(), self.offsets[0] + 30, v)
    }

    pub fn set_present(&mut self, v: bool) -> Result<(), CdrError> {
        wr_bool(self.buf.as_mut(), self.offsets[0] + 31, v)
    }
}

// ── Registry ────────────────────────────────────────────────────────

/// Check if a type name is supported by this module.
pub fn is_type_supported(type_name: &str) -> bool {
    matches!(
        type_name,
        "BatteryState"
            | "CameraInfo"
            | "CompressedImage"
            | "FluidPressure"
            | "Image"
            | "Imu"
            | "MagneticField"
            | "NavSatFix"
            | "NavSatStatus"
            | "PointCloud2"
            | "PointField"
            | "RegionOfInterest"
            | "Temperature"
    )
}

/// List all type schema names in this module.
pub fn list_types() -> &'static [&'static str] {
    &[
        "sensor_msgs/msg/BatteryState",
        "sensor_msgs/msg/CameraInfo",
        "sensor_msgs/msg/CompressedImage",
        "sensor_msgs/msg/FluidPressure",
        "sensor_msgs/msg/Image",
        "sensor_msgs/msg/Imu",
        "sensor_msgs/msg/MagneticField",
        "sensor_msgs/msg/NavSatFix",
        "sensor_msgs/msg/NavSatStatus",
        "sensor_msgs/msg/PointCloud2",
        "sensor_msgs/msg/PointField",
        "sensor_msgs/msg/RegionOfInterest",
        "sensor_msgs/msg/Temperature",
    ]
}

// SchemaType implementations
use crate::schema_registry::SchemaType;

impl SchemaType for NavSatStatus {
    const SCHEMA_NAME: &'static str = "sensor_msgs/msg/NavSatStatus";
}

impl SchemaType for RegionOfInterest {
    const SCHEMA_NAME: &'static str = "sensor_msgs/msg/RegionOfInterest";
}

#[cfg(test)]
#[allow(deprecated)] // Tests exercise Image::new / PointCloud2::new, which are deprecated in 3.2.0 but still supported until 4.0.
mod tests {
    use super::*;
    use crate::builtin_interfaces::Time;
    use crate::cdr::{decode_fixed, encode_fixed};
    use crate::geometry_msgs::{Quaternion, Vector3};

    #[test]
    fn compressed_image_roundtrip() {
        let img = CompressedImage::new(
            Time::new(100, 500_000_000),
            "camera",
            "jpeg",
            &[0xFF, 0xD8, 0xFF],
        )
        .unwrap();
        assert_eq!(img.stamp(), Time::new(100, 500_000_000));
        assert_eq!(img.frame_id(), "camera");
        assert_eq!(img.format(), "jpeg");
        assert_eq!(img.data(), &[0xFF, 0xD8, 0xFF]);

        let bytes = img.to_cdr();
        let decoded = CompressedImage::from_cdr(bytes).unwrap();
        assert_eq!(decoded.format(), "jpeg");
        assert_eq!(decoded.data(), &[0xFF, 0xD8, 0xFF]);
    }

    #[test]
    fn image_roundtrip() {
        let data = vec![128u8; 1920 * 480];
        let img = Image::new(
            Time::new(100, 500_000_000),
            "camera_optical",
            480,
            640,
            "rgb8",
            0,
            1920,
            &data,
        )
        .unwrap();
        assert_eq!(img.height(), 480);
        assert_eq!(img.width(), 640);
        assert_eq!(img.encoding(), "rgb8");
        assert_eq!(img.is_bigendian(), 0);
        assert_eq!(img.step(), 1920);
        assert_eq!(img.data().len(), 1920 * 480);

        let bytes = img.to_cdr();
        let decoded = Image::from_cdr(bytes).unwrap();
        assert_eq!(decoded.height(), 480);
        assert_eq!(decoded.width(), 640);
    }

    #[test]
    fn imu_roundtrip() {
        let imu = Imu::new(
            Time::new(100, 0),
            "imu_link",
            Quaternion {
                x: 0.0,
                y: 0.0,
                z: 0.0,
                w: 1.0,
            },
            [0.0; 9],
            Vector3 {
                x: 0.1,
                y: 0.2,
                z: 9.8,
            },
            [0.0; 9],
            Vector3 {
                x: 0.0,
                y: 0.0,
                z: 0.0,
            },
            [0.0; 9],
        )
        .unwrap();
        assert_eq!(imu.stamp(), Time::new(100, 0));
        let bytes = imu.to_cdr();
        let decoded = Imu::from_cdr(bytes).unwrap();
        assert_eq!(decoded.orientation().w, 1.0);
        assert!((decoded.angular_velocity().z - 9.8).abs() < 1e-10);
    }

    #[test]
    fn nav_sat_fix_roundtrip() {
        let fix = NavSatFix::new(
            Time::new(100, 0),
            "gps",
            NavSatStatus {
                status: 0,
                service: 1,
            },
            45.5017,
            -73.5673,
            100.0,
            [1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0],
            2,
        )
        .unwrap();
        let bytes = fix.to_cdr();
        let decoded = NavSatFix::from_cdr(bytes).unwrap();
        assert!((decoded.latitude() - 45.5017).abs() < 1e-10);
        assert_eq!(decoded.position_covariance_type(), 2);
    }

    #[test]
    fn nav_sat_status_roundtrip() {
        let status = NavSatStatus {
            status: 0,
            service: 1,
        };
        let bytes = encode_fixed(&status).unwrap();
        let decoded: NavSatStatus = decode_fixed(&bytes).unwrap();
        assert_eq!(status, decoded);
    }

    #[test]
    fn region_of_interest_roundtrip() {
        let roi = RegionOfInterest {
            x_offset: 10,
            y_offset: 20,
            height: 100,
            width: 200,
            do_rectify: true,
        };
        let bytes = encode_fixed(&roi).unwrap();
        let decoded: RegionOfInterest = decode_fixed(&bytes).unwrap();
        assert_eq!(roi, decoded);
    }

    #[test]
    fn point_cloud2_roundtrip() {
        let fields = [
            PointFieldView {
                name: "x",
                offset: 0,
                datatype: 7,
                count: 1,
            },
            PointFieldView {
                name: "y",
                offset: 4,
                datatype: 7,
                count: 1,
            },
            PointFieldView {
                name: "z",
                offset: 8,
                datatype: 7,
                count: 1,
            },
        ];
        let data = vec![0u8; 12288];
        let cloud = PointCloud2::new(
            Time::new(100, 0),
            "lidar",
            1,
            1024,
            &fields,
            false,
            12,
            12288,
            &data,
            true,
        )
        .unwrap();
        let bytes = cloud.to_cdr();
        let decoded = PointCloud2::from_cdr(bytes).unwrap();
        assert_eq!(decoded.height(), 1);
        assert_eq!(decoded.width(), 1024);
        assert_eq!(decoded.fields_len(), 3);
        assert!(decoded.is_dense());
    }

    #[test]
    fn point_cloud2_fields_iter() {
        let fields = [
            PointFieldView {
                name: "x",
                offset: 0,
                datatype: 7,
                count: 1,
            },
            PointFieldView {
                name: "y",
                offset: 4,
                datatype: 7,
                count: 1,
            },
            PointFieldView {
                name: "z",
                offset: 8,
                datatype: 7,
                count: 1,
            },
        ];
        let data = vec![0u8; 36]; // 3 points × 12 bytes
        let cloud = PointCloud2::new(
            Time::new(100, 0),
            "lidar",
            1,
            3,
            &fields,
            false,
            12,
            36,
            &data,
            true,
        )
        .unwrap();
        let cdr = cloud.to_cdr();
        let decoded = PointCloud2::from_cdr(cdr).unwrap();

        let iter_fields: Vec<_> = decoded.fields_iter().collect();
        assert_eq!(iter_fields.len(), 3);
        assert_eq!(iter_fields[0].name, "x");
        assert_eq!(iter_fields[1].name, "y");
        assert_eq!(iter_fields[2].name, "z");
        assert_eq!(iter_fields[0].offset, 0);
        assert_eq!(iter_fields[1].offset, 4);
        assert_eq!(iter_fields[2].offset, 8);
        assert_eq!(decoded.point_count(), 3);
    }

    #[test]
    fn camera_info_roundtrip() {
        let roi = RegionOfInterest {
            x_offset: 0,
            y_offset: 0,
            height: 480,
            width: 640,
            do_rectify: false,
        };
        let cam = CameraInfo::new(
            Time::new(100, 0),
            "camera",
            480,
            640,
            "plumb_bob",
            &[0.1, -0.2, 0.0, 0.0, 0.0],
            [500.0, 0.0, 320.0, 0.0, 500.0, 240.0, 0.0, 0.0, 1.0],
            [1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0],
            [
                500.0, 0.0, 320.0, 0.0, 0.0, 500.0, 240.0, 0.0, 0.0, 0.0, 1.0, 0.0,
            ],
            1,
            1,
            roi,
        )
        .unwrap();
        let bytes = cam.to_cdr();
        let decoded = CameraInfo::from_cdr(bytes).unwrap();
        assert_eq!(decoded.height(), 480);
        assert_eq!(decoded.width(), 640);
        assert_eq!(decoded.distortion_model(), "plumb_bob");
        assert_eq!(decoded.d_len(), 5);
        assert_eq!(decoded.binning_x(), 1);
    }

    // EDGEAI-1243 regression: NavSatFix accessors must return the encoded
    // values for every valid `frame_id` length, not just the one used in the
    // golden fixture. The pre-fix `fixed_base = cdr_align(offsets[0] + 4, 8)`
    // formula was wrong whenever the CDR-relative position of `offsets[0]`
    // landed at a residue that made `NavSatStatus` occupy 3 bytes rather
    // than 4. Sweep frame_id lengths 0..=16 to cover every mod-8 residue.
    #[test]
    fn navsatfix_accessors_robust_across_frame_id_alignments() {
        let lat = 43.6532_f64;
        let lon = -79.3832_f64;
        let alt = 150.0_f64;
        let cov = [0.1, 0.0, 0.0, 0.0, 0.2, 0.0, 0.0, 0.0, 0.3_f64];
        let cov_type = 2_u8;
        let status = NavSatStatus {
            status: 0,
            service: 1,
        };
        for len in 0..=16_usize {
            let frame_id: String = "x".repeat(len);
            let fix = NavSatFix::new(
                Time::new(1, 0),
                &frame_id,
                status,
                lat,
                lon,
                alt,
                cov,
                cov_type,
            )
            .unwrap();
            let bytes = fix.to_cdr();
            let view = NavSatFix::from_cdr(&bytes[..]).unwrap();
            assert_eq!(view.frame_id(), frame_id, "frame_id at len={len}");
            let rx_status = view.status();
            assert_eq!(rx_status.status, 0, "status.status at len={len}");
            assert_eq!(rx_status.service, 1, "status.service at len={len}");
            assert_eq!(view.latitude(), lat, "latitude at len={len}");
            assert_eq!(view.longitude(), lon, "longitude at len={len}");
            assert_eq!(view.altitude(), alt, "altitude at len={len}");
            assert_eq!(
                view.position_covariance(),
                cov,
                "position_covariance at len={len}"
            );
            assert_eq!(
                view.position_covariance_type(),
                cov_type,
                "position_covariance_type at len={len}"
            );
        }
    }

    // Direct reproduction of the EDGEAI-1243 bug report: `"gps_link"`
    // (8-char frame_id) is the canonical ROS 2 GPS frame and was the
    // original trigger. Kept alongside the parametric sweep so the
    // connection to the JIRA is explicit.
    #[test]
    fn navsatfix_gps_link_frame_id_regression() {
        let status = NavSatStatus {
            status: 0,
            service: 1,
        };
        let fix = NavSatFix::new(
            Time::new(0, 0),
            "gps_link",
            status,
            43.6532,
            -79.3832,
            150.0,
            [0.0; 9],
            0,
        )
        .unwrap();
        let bytes = fix.to_cdr();
        let rx = NavSatFix::from_cdr(&bytes[..]).unwrap();
        assert_eq!(rx.latitude(), 43.6532);
        assert_eq!(rx.longitude(), -79.3832);
        assert_eq!(rx.altitude(), 150.0);
    }

    /// Guard: in-place scalar setters on every buffer-backed sensor_msgs
    /// type must produce byte-identical CDR to the equivalent builder.
    #[test]
    fn sensor_setter_byte_parity() {
        // Imu
        let imu_a = Imu::builder()
            .stamp(Time::new(100, 500))
            .frame_id("imu_link")
            .orientation(Quaternion {
                x: 0.1,
                y: 0.2,
                z: 0.3,
                w: 0.4,
            })
            .orientation_covariance([1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0])
            .angular_velocity(Vector3 {
                x: 0.11,
                y: 0.22,
                z: 0.33,
            })
            .angular_velocity_covariance([10.0; 9])
            .linear_acceleration(Vector3 {
                x: 0.44,
                y: 0.55,
                z: 0.66,
            })
            .linear_acceleration_covariance([20.0; 9])
            .build()
            .unwrap();
        let mut imu_b = Imu::builder()
            .stamp(Time::new(0, 0))
            .frame_id("imu_link")
            .build()
            .unwrap();
        imu_b.set_stamp(Time::new(100, 500)).unwrap();
        imu_b
            .set_orientation(Quaternion {
                x: 0.1,
                y: 0.2,
                z: 0.3,
                w: 0.4,
            })
            .unwrap();
        imu_b
            .set_orientation_covariance([1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0])
            .unwrap();
        imu_b
            .set_angular_velocity(Vector3 {
                x: 0.11,
                y: 0.22,
                z: 0.33,
            })
            .unwrap();
        imu_b.set_angular_velocity_covariance([10.0; 9]).unwrap();
        imu_b
            .set_linear_acceleration(Vector3 {
                x: 0.44,
                y: 0.55,
                z: 0.66,
            })
            .unwrap();
        imu_b.set_linear_acceleration_covariance([20.0; 9]).unwrap();
        assert_eq!(imu_a.as_cdr(), imu_b.as_cdr(), "Imu byte mismatch");

        // NavSatFix — exercises the EDGEAI-1243-sensitive NavSatStatus setter.
        let nsf_a = NavSatFix::builder()
            .stamp(Time::new(5, 6))
            .frame_id("gps")
            .status(NavSatStatus {
                status: 1,
                service: 3,
            })
            .latitude(45.5)
            .longitude(-73.6)
            .altitude(100.0)
            .position_covariance([0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9])
            .position_covariance_type(2)
            .build()
            .unwrap();
        let mut nsf_b = NavSatFix::builder()
            .stamp(Time::new(0, 0))
            .frame_id("gps")
            .build()
            .unwrap();
        nsf_b.set_stamp(Time::new(5, 6)).unwrap();
        nsf_b
            .set_status(NavSatStatus {
                status: 1,
                service: 3,
            })
            .unwrap();
        nsf_b.set_latitude(45.5).unwrap();
        nsf_b.set_longitude(-73.6).unwrap();
        nsf_b.set_altitude(100.0).unwrap();
        nsf_b
            .set_position_covariance([0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9])
            .unwrap();
        nsf_b.set_position_covariance_type(2).unwrap();
        assert_eq!(nsf_a.as_cdr(), nsf_b.as_cdr(), "NavSatFix byte mismatch");

        // PointField
        let pf_a = PointField::builder()
            .name("x")
            .offset(16)
            .datatype(7)
            .count(3)
            .build()
            .unwrap();
        let mut pf_b = PointField::builder().name("x").build().unwrap();
        pf_b.set_offset(16).unwrap();
        pf_b.set_datatype(7).unwrap();
        pf_b.set_count(3).unwrap();
        assert_eq!(pf_a.as_cdr(), pf_b.as_cdr(), "PointField byte mismatch");

        // PointCloud2
        let pc_a = PointCloud2::builder()
            .stamp(Time::new(1, 2))
            .frame_id("base_link")
            .height(480)
            .width(640)
            .is_bigendian(true)
            .point_step(16)
            .row_step(16 * 640)
            .is_dense(true)
            .build()
            .unwrap();
        let mut pc_b = PointCloud2::builder()
            .stamp(Time::new(0, 0))
            .frame_id("base_link")
            .build()
            .unwrap();
        pc_b.set_stamp(Time::new(1, 2)).unwrap();
        pc_b.set_height(480).unwrap();
        pc_b.set_width(640).unwrap();
        pc_b.set_is_bigendian(true).unwrap();
        pc_b.set_point_step(16).unwrap();
        pc_b.set_row_step(16 * 640).unwrap();
        pc_b.set_is_dense(true).unwrap();
        assert_eq!(pc_a.as_cdr(), pc_b.as_cdr(), "PointCloud2 byte mismatch");

        // CameraInfo
        let k = [1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0];
        let r = [10.0, 11.0, 12.0, 13.0, 14.0, 15.0, 16.0, 17.0, 18.0];
        let p = [
            20.0, 21.0, 22.0, 23.0, 24.0, 25.0, 26.0, 27.0, 28.0, 29.0, 30.0, 31.0,
        ];
        let roi = RegionOfInterest {
            x_offset: 1,
            y_offset: 2,
            height: 3,
            width: 4,
            do_rectify: true,
        };
        let ci_a = CameraInfo::builder()
            .stamp(Time::new(7, 8))
            .frame_id("cam")
            .height(480)
            .width(640)
            .distortion_model("plumb_bob")
            .d(&[0.1, 0.2])
            .k(k)
            .r(r)
            .p(p)
            .binning_x(2)
            .binning_y(3)
            .roi(roi)
            .build()
            .unwrap();
        let mut ci_b = CameraInfo::builder()
            .stamp(Time::new(0, 0))
            .frame_id("cam")
            .distortion_model("plumb_bob")
            .d(&[0.1, 0.2])
            .build()
            .unwrap();
        ci_b.set_stamp(Time::new(7, 8)).unwrap();
        ci_b.set_height(480).unwrap();
        ci_b.set_width(640).unwrap();
        ci_b.set_k(k).unwrap();
        ci_b.set_r(r).unwrap();
        ci_b.set_p(p).unwrap();
        ci_b.set_binning_x(2).unwrap();
        ci_b.set_binning_y(3).unwrap();
        ci_b.set_roi(roi).unwrap();
        assert_eq!(ci_a.as_cdr(), ci_b.as_cdr(), "CameraInfo byte mismatch");

        // MagneticField
        let mf_a = MagneticField::builder()
            .stamp(Time::new(9, 10))
            .frame_id("imu")
            .magnetic_field(Vector3 {
                x: 1.0,
                y: 2.0,
                z: 3.0,
            })
            .magnetic_field_covariance([1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0])
            .build()
            .unwrap();
        let mut mf_b = MagneticField::builder()
            .stamp(Time::new(0, 0))
            .frame_id("imu")
            .build()
            .unwrap();
        mf_b.set_stamp(Time::new(9, 10)).unwrap();
        mf_b.set_magnetic_field(Vector3 {
            x: 1.0,
            y: 2.0,
            z: 3.0,
        })
        .unwrap();
        mf_b.set_magnetic_field_covariance([1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0])
            .unwrap();
        assert_eq!(mf_a.as_cdr(), mf_b.as_cdr(), "MagneticField byte mismatch");

        // FluidPressure
        let fp_a = FluidPressure::builder()
            .stamp(Time::new(11, 12))
            .frame_id("barometer")
            .fluid_pressure(101_325.0)
            .variance(0.5)
            .build()
            .unwrap();
        let mut fp_b = FluidPressure::builder()
            .stamp(Time::new(0, 0))
            .frame_id("barometer")
            .build()
            .unwrap();
        fp_b.set_stamp(Time::new(11, 12)).unwrap();
        fp_b.set_fluid_pressure(101_325.0).unwrap();
        fp_b.set_variance(0.5).unwrap();
        assert_eq!(fp_a.as_cdr(), fp_b.as_cdr(), "FluidPressure byte mismatch");

        // Temperature
        let t_a = Temperature::builder()
            .stamp(Time::new(13, 14))
            .frame_id("temp")
            .temperature(25.5)
            .variance(0.1)
            .build()
            .unwrap();
        let mut t_b = Temperature::builder()
            .stamp(Time::new(0, 0))
            .frame_id("temp")
            .build()
            .unwrap();
        t_b.set_stamp(Time::new(13, 14)).unwrap();
        t_b.set_temperature(25.5).unwrap();
        t_b.set_variance(0.1).unwrap();
        assert_eq!(t_a.as_cdr(), t_b.as_cdr(), "Temperature byte mismatch");

        // BatteryState
        let bs_a = BatteryState::builder()
            .stamp(Time::new(15, 16))
            .frame_id("batt")
            .voltage(12.1)
            .temperature(25.0)
            .current(-1.5)
            .charge(0.5)
            .capacity(2.0)
            .design_capacity(2.5)
            .percentage(0.75)
            .power_supply_status(1)
            .power_supply_health(2)
            .power_supply_technology(3)
            .present(true)
            .build()
            .unwrap();
        let mut bs_b = BatteryState::builder()
            .stamp(Time::new(0, 0))
            .frame_id("batt")
            .build()
            .unwrap();
        bs_b.set_stamp(Time::new(15, 16)).unwrap();
        bs_b.set_voltage(12.1).unwrap();
        bs_b.set_temperature(25.0).unwrap();
        bs_b.set_current(-1.5).unwrap();
        bs_b.set_charge(0.5).unwrap();
        bs_b.set_capacity(2.0).unwrap();
        bs_b.set_design_capacity(2.5).unwrap();
        bs_b.set_percentage(0.75).unwrap();
        bs_b.set_power_supply_status(1).unwrap();
        bs_b.set_power_supply_health(2).unwrap();
        bs_b.set_power_supply_technology(3).unwrap();
        bs_b.set_present(true).unwrap();
        assert_eq!(bs_a.as_cdr(), bs_b.as_cdr(), "BatteryState byte mismatch");
    }
}