+#![allow(unused_variables)]
+use endian::{Endian, Parse};
+use std::io::{BufReader, Error as IoError, Read};
+use thiserror::Error;
+
+pub mod endian;
+
+#[derive(Error, Debug)]
+pub enum Error {
+ #[error("Not an SPSS system file")]
+ NotASystemFile,
+
+ #[error("I/O error ({source})")]
+ Io {
+ #[from]
+ source: IoError,
+ },
+
+ #[error("Invalid SAV compression code {0}")]
+ InvalidSavCompression(u32),
+
+ #[error("Invalid ZSAV compression code {0}")]
+ InvalidZsavCompression(u32),
+}
+
+#[derive(Error, Debug)]
+pub enum Warning {
+ #[error("Unexpected floating-point bias {0} or unrecognized floating-point format.")]
+ UnexpectedBias(f64),
+}
+
+#[derive(Copy, Clone, Debug)]
+pub enum Compression {
+ Simple,
+ ZLib,
+}
+
+pub struct Reader<R: Read> {
+ r: BufReader<R>,
+}
+
+pub const ASCII_MAGIC: &[u8; 4] = b"$FL2";
+pub const ASCII_ZMAGIC: &[u8; 4] = b"$FL3";
+pub const EBCDIC_MAGIC: &[u8; 4] = &[0x5b, 0xc6, 0xd3, 0xf2];
+
+pub struct FileHeader {
+ /// First 4 bytes of the file, one of `ASCII_MAGIC`, `ASCII_ZMAGIC`, and
+ /// `EBCDIC_MAGIC`.
+ pub magic: [u8; 4],
+
+ /// True if `magic` indicates that this file contained zlib-compressed data.
+ pub is_zsav: bool,
+
+ /// True if `magic` indicates that this file contained EBCDIC data.
+ pub is_ebcdic: bool,
+
+ /// 0-based variable index of the weight variable, or `None` if the file is
+ /// unweighted.
+ pub weight_index: Option<u32>,
+
+ /// Number of variable positions, or `None` if the value in the file is
+ /// questionably trustworthy.
+ pub nominal_case_size: Option<u32>,
+
+ /// `dd mmm yy` in the file's encoding.
+ pub creation_date: [u8; 9],
+
+ /// `HH:MM:SS` in the file's encoding.
+ pub creation_time: [u8; 8],
+
+ /// Eye-catcher string, then product name, in the file's encoding. Padded
+ /// on the right with spaces.
+ pub eye_catcher: [u8; 60],
+
+ /// File label, in the file's encoding. Padded on the right with spaces.
+ pub file_label: [u8; 64],
+}
+
+impl<R: Read> Reader<R> {
+ pub fn new(r: R, warn: impl Fn(Warning)) -> Result<Reader<R>, Error> {
+ let mut r = BufReader::new(r);
+
+ let magic: [u8; 4] = read_bytes(&mut r)?;
+ let (is_zsav, is_ebcdic) = match &magic {
+ ASCII_MAGIC => (false, false),
+ ASCII_ZMAGIC => (true, false),
+ EBCDIC_MAGIC => (false, true),
+ _ => return Err(Error::NotASystemFile),
+ };
+
+ let eye_catcher: [u8; 60] = read_bytes(&mut r)?;
+ let layout_code: [u8; 4] = read_bytes(&mut r)?;
+ let endianness = Endian::identify_u32(2, layout_code)
+ .or_else(|| Endian::identify_u32(2, layout_code))
+ .ok_or_else(|| Error::NotASystemFile)?;
+
+ let nominal_case_size: u32 = endianness.parse(read_bytes(&mut r)?);
+ let nominal_case_size = (nominal_case_size <= u32::MAX / 32).then_some(nominal_case_size);
+
+ let compression_code: u32 = endianness.parse(read_bytes(&mut r)?);
+ let compression = match (is_zsav, compression_code) {
+ (false, 0) => None,
+ (false, 1) => Some(Compression::Simple),
+ (true, 2) => Some(Compression::ZLib),
+ (false, code) => return Err(Error::InvalidSavCompression(code)),
+ (true, code) => return Err(Error::InvalidZsavCompression(code)),
+ };
+
+ let weight_index: u32 = endianness.parse(read_bytes(&mut r)?);
+ let weight_index = (weight_index > 0).then_some(weight_index - 1);
+
+ let n_cases: u32 = endianness.parse(read_bytes(&mut r)?);
+ let n_cases = (n_cases <= u32::MAX / 4).then_some(n_cases);
+
+ let bias: f64 = endianness.parse(read_bytes(&mut r)?);
+ if bias != 100.0 {
+ warn(Warning::UnexpectedBias(bias))
+ }
+
+ let creation_date: [u8; 9] = read_bytes(&mut r)?;
+ let creation_time: [u8; 8] = read_bytes(&mut r)?;
+ let file_label: [u8; 64] = read_bytes(&mut r)?;
+ let _: [u8; 3] = read_bytes(&mut r)?;
+
+ let header = FileHeader {
+ magic,
+ is_zsav,
+ is_ebcdic,
+ weight_index,
+ nominal_case_size,
+ creation_date,
+ creation_time,
+ eye_catcher,
+ file_label,
+ };
+
+ Ok(Reader { r })
+ }
+}
+
+fn read_bytes<const N: usize, R: Read>(r: &mut R) -> Result<[u8; N], IoError> {
+ let mut buf = [0; N];
+ r.read_exact(&mut buf)?;
+ Ok(buf)
+}
+
+/*
+fn trim_end(mut s: Vec<u8>, c: u8) -> Vec<u8> {
+ while s.last() == Some(&c) {
+ s.pop();
+ }
+ s
+}
+
+fn skip_bytes<R: Read>(r: &mut R, mut n: u64) -> Result<(), IoError> {
+ let mut buf = [0; 1024];
+ while n > 0 {
+ let chunk = u64::min(n, buf.len() as u64);
+ r.read_exact(&mut buf[0..chunk as usize])?;
+ n -= chunk;
+ }
+ Ok(())
+}
+
+*/