commit 6f1c60fc70eaf7cecd30c36918d4af1096675359
Author: Spencer Killen <sjkillen@ualberta.ca>
Date:   Sun Nov 26 16:16:45 2023 -0700

    proof of concept MDD

diff --git a/.gitignore b/.gitignore
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+++ b/.gitignore
@@ -0,0 +1 @@
+/target
diff --git a/Cargo.lock b/Cargo.lock
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+++ b/Cargo.lock
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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "pointcache"
+version = "0.1.0"
diff --git a/Cargo.toml b/Cargo.toml
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+++ b/Cargo.toml
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+[package]
+name = "pointcache"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/README.md b/README.md
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+++ b/README.md
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+# Parser / Encoder for pointcache file formats
+
+## References
+- https://github.com/brainexcerpts/MDD_file_exporter
\ No newline at end of file
diff --git a/output.mdd b/output.mdd
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diff --git a/src/lib.rs b/src/lib.rs
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+++ b/src/lib.rs
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+use std::fmt::Display;
+use std::io::Write;
+use std::mem::size_of;
+use std::ops::Range;
+use std::{
+    error::Error,
+    fs::File,
+    io::{BufReader, Read, Seek, SeekFrom},
+    iter::repeat,
+};
+
+pub trait PointCache {
+    fn map<F: FnMut(MDDFrame) -> Result<(), Box<dyn Error>>>(
+        infile: File,
+        op: F,
+    ) -> Result<(), Box<dyn Error>>;
+    fn map_to<F: FnMut(MDDFrame) -> Result<MDDFrame, Box<dyn Error>>>(
+        infile: File,
+        outfile: File,
+        op: F,
+    ) -> Result<(), Box<dyn Error>>;
+}
+
+pub struct MDDSeekableFile;
+struct MDDSeekableFileReader {
+    total_frames: i32,
+    total_points: i32,
+    data: Box<dyn Iterator<Item = Result<MDDFrame, Box<dyn Error>>>>,
+}
+
+#[derive(Debug)]
+pub struct Point {
+    x: f32,
+    y: f32,
+    z: f32,
+}
+#[derive(Debug)]
+pub struct MDDFrame {
+    frame_idx: usize,
+    point_idx: usize,
+    time: f32,
+    point: Point,
+}
+
+impl MDDSeekableFile {
+    fn read_header(infile: &mut File) -> Result<(i32, i32), Box<dyn Error>> {
+        infile.seek(SeekFrom::Start(0));
+        let mut buff = [0u8; size_of::<i32>()];
+        infile.read_exact(&mut buff)?;
+        let total_frames = i32::from_be_bytes(buff);
+        infile.read_exact(&mut buff)?;
+        let total_points = i32::from_be_bytes(buff);
+
+        return Ok((total_frames, total_points));
+    }
+    fn write_header(
+        outfile: &mut File,
+        total_frames: i32,
+        total_points: i32,
+    ) -> Result<(), Box<dyn Error>> {
+        outfile.seek(SeekFrom::Start(0));
+        outfile.write_all(&total_frames.to_be_bytes())?;
+        outfile.write_all(&total_points.to_be_bytes())?;
+        Ok(())
+    }
+    fn read(mut infile: File) -> Result<MDDSeekableFileReader, Box<dyn Error>> {
+        let (total_frames, total_points) = MDDSeekableFile::read_header(&mut infile)?;
+        let time_byte_offset = (total_frames as usize) * size_of::<f32>();
+
+        let mut buff = [0u8; size_of::<f32>()];
+        let times = Box::new(
+            repeat(())
+                .map::<Result<_, Box<dyn Error>>, _>(move |()| {
+                    //times.read_exact(&mut buff)?;
+                    //Ok(f32::from_be_bytes(buff))
+                    Ok(0.0)
+                })
+                .take(total_frames.try_into()?),
+        );
+
+        let header_size: u64 = (size_of::<i32>() * 2).try_into()?;
+        let f32_size: u64 = size_of::<f32>().try_into()?;
+        let mut buff = [0u8; size_of::<f32>()];
+        let data = Box::new(
+            (0..((total_frames * total_points) as u64)).map::<Result<_, Box<dyn Error>>, _>(
+                move |count| {
+                    let frame_idx: usize = (count / (total_points as u64)).try_into()?;
+                    let time_offset: u64 = f32_size * (frame_idx as u64);
+                    let time_size: u64 = f32_size * (total_frames as u64);
+                    let data_offset: u64 = f32_size * count * 3;
+
+                    infile.seek(SeekFrom::Start(header_size + time_offset))?;
+                    infile.read_exact(&mut buff)?;
+                    let time = f32::from_be_bytes(buff);
+
+                    infile.seek(SeekFrom::Start(header_size + time_size + data_offset))?;
+                    infile.read_exact(&mut buff)?;
+                    let x = f32::from_be_bytes(buff);
+                    infile.read_exact(&mut buff)?;
+                    let y = f32::from_be_bytes(buff);
+                    infile.read_exact(&mut buff)?;
+                    let z = f32::from_be_bytes(buff);
+                    let point = Point { x, y, z };
+
+                    let point_idx: usize = (count % (total_points as u64)).try_into()?;
+                    Ok(MDDFrame {
+                        frame_idx,
+                        point_idx,
+                        time,
+                        point,
+                    })
+                },
+            ),
+        );
+
+        Ok(MDDSeekableFileReader {
+            total_frames,
+            total_points,
+            data,
+        })
+    }
+}
+
+#[derive(Debug)]
+struct ExaustedPointsUnexpectedly;
+impl Display for ExaustedPointsUnexpectedly {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "ExaustedPointsUnexpectedly")
+    }
+}
+impl Error for ExaustedPointsUnexpectedly {}
+
+impl PointCache for MDDSeekableFile {
+    fn map<F>(infile: File, mut op: F) -> Result<(), Box<dyn Error>>
+    where
+        F: FnMut(MDDFrame) -> Result<(), Box<dyn Error>>,
+    {
+        let MDDSeekableFileReader {
+            total_frames: _,
+            total_points: _,
+            data,
+        } = MDDSeekableFile::read(infile)?;
+
+        for frame in data {
+            op(frame?)?;
+        }
+
+        Ok(())
+    }
+
+    fn map_to<F>(mut infile: File, mut outfile: File, mut op: F) -> Result<(), Box<dyn Error>>
+    where
+        F: FnMut(MDDFrame) -> Result<MDDFrame, Box<dyn Error>>,
+    {
+        let (total_frames, total_points) = MDDSeekableFile::read_header(&mut infile)?;
+        MDDSeekableFile::write_header(&mut outfile, total_frames, total_points)?;
+
+        let header_size: u64 = (size_of::<i32>() * 2).try_into()?;
+        let f32_size: u64 = size_of::<f32>().try_into()?;
+        let mut count = 0;
+
+        Self::map(infile, |frame| {
+            let frame = op(frame)?;
+            let frame_idx: u64 = count / (total_points as u64);
+            let time_offset: u64 = f32_size * frame_idx;
+            let time_size: u64 = f32_size * (total_frames as u64);
+            let data_offset: u64 = f32_size * count * 3;
+
+            outfile.seek(SeekFrom::Start(header_size + time_offset))?;
+            outfile.write_all(&frame.time.to_be_bytes())?;
+
+            outfile.seek(SeekFrom::Start(header_size + time_size + data_offset))?;
+            outfile.write_all(&frame.point.x.to_be_bytes())?;
+            outfile.write_all(&frame.point.y.to_be_bytes())?;
+            outfile.write_all(&frame.point.z.to_be_bytes())?;
+
+            count += 1;
+            Ok(())
+        })?;
+        Ok(())
+    }
+}
+
+pub fn add(left: usize, right: usize) -> usize {
+    left + right
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn it_works() -> Result<(), Box<dyn Error>> {
+        let infile = File::open("test_cube.mdd")?;
+        let outfile = File::create("output.mdd")?;
+        println!("MAPPING test_cube.mdd to output.mdd");
+        MDDSeekableFile::map_to(infile, outfile, |mut frame| {
+            frame.point.x = frame.frame_idx as f32;
+            frame.point.y = (frame.frame_idx * 2) as f32;
+            frame.point.z = 0.0;
+
+            println!("{:?}", frame);
+            Ok(frame)
+        })?;
+        println!("\nReading back output.mdd");
+        let infile = File::open("output.mdd")?;
+        MDDSeekableFile::map(infile, |frame| {
+            println!("{:?}", frame);
+            Ok(())
+        })?;
+        Ok(())
+    }
+}
diff --git a/test_cube.mdd b/test_cube.mdd
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