pdfrum-type1 0.1.0

//! Getting from a `/FontFile` blob to two byte ranges: the ASCII clear portion
//! and the still-encrypted private portion.
//!
//! A Type 1 font program arrives in one of three wrappers, and the font dict's
//! `/Length1` `/Length2` `/Length3` cannot be trusted to describe them —
//! PDFium ignores those keys entirely and so do we, sniffing the bytes instead.
//!
//! - **PFB**: a chain of `[0x80, type, len:u32le, data…]` records, type 1 for
//!   ASCII text, 2 for binary, 3 for end-of-file. The clear part is the leading
//!   text record; the binary records concatenated are the eexec ciphertext.
//! - **PFA**: plain ASCII beginning `%!PS-AdobeFont` or `%!FontType1`, with the
//!   private portion written as hexadecimal after the `eexec` keyword.
//! - **bare**: neither marker. Treated as PFA-shaped, because that is what a
//!   stripped-down embedded font usually is.
//!
//! The output is deliberately owned rather than borrowed: PFB's binary
//! segments are non-contiguous and PFA's hex needs decoding, so a `&[u8]` view
//! of the ciphertext does not exist in the general case.

use crate::error::Error;
use pdfrum_common::{DiagKind, Diagnostics, Severity, hex_digit};

/// Which wrapper the bytes turned out to be in. Reported so callers (and
/// tests) can tell a genuine PFA from a bare program that merely parses like
/// one.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Container {
    /// Segmented binary container (`0x80 0x01 …`).
    Pfb,
    /// ASCII container with a `%!PS-AdobeFont` or `%!FontType1` banner.
    Pfa,
    /// No recognisable banner; read as if it were PFA.
    Bare,
}

/// A font program split into its two halves, ready for `eexec` decryption.
#[derive(Debug, Clone)]
pub struct Split {
    /// Which wrapper this came out of.
    pub container: Container,
    /// The cleartext PostScript preamble: everything up to and including the
    /// `eexec` keyword's whitespace.
    pub clear: Vec<u8>,
    /// The still-encrypted private portion, hex-decoded if it was hex.
    pub cipher: Vec<u8>,
}

const PFB_MARKER: u8 = 0x80;
const PFB_TEXT: u8 = 1;
const PFB_BINARY: u8 = 2;
const PFB_EOF: u8 = 3;

/// A Type 1 program as a PDF `/FontFile` stream: the bytes to store, and the
/// ISO 32000-1 §9.9 table 127 lengths that partition them.
///
/// The two are produced together because table 127 defines the three lengths
/// as a *partition of the stream's decoded data* — `/Length1` the clear-text
/// portion, `/Length2` the encrypted portion, `/Length3` the fixed-content
/// (`cleartomark`) portion — so computing lengths for one byte string and
/// storing another is the defect this type exists to make unrepresentable.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct FontFile {
    /// The bytes to write as the stream's decoded data. `length1 + length2 +
    /// length3 == program.len()` always holds.
    pub program: Vec<u8>,
    /// Bytes of clear-text ASCII, up to and including the `eexec` line.
    pub length1: u32,
    /// Bytes of the `eexec`-encrypted private portion, in whatever form it is
    /// stored — binary for a PFB, and still hexadecimal for a PFA whose
    /// private portion was written that way, which §9.9 permits.
    pub length2: u32,
    /// Bytes of the fixed 512-zeros-plus-`cleartomark` trailer, 0 when the
    /// program carries none.
    pub length3: u32,
}

/// Unwrap a Type 1 program into the `/FontFile` stream a PDF writer stores.
///
/// A PFB is a container, not a font program: its record headers and end marker
/// are framing that must not reach the stream, so the record bodies are
/// concatenated into the PFA-shaped raw program table 127 describes and the
/// three lengths are those bodies' sizes. A PFA or bare program is stored
/// as-is, with `/Length1` ending at the `eexec` boundary, `/Length3` covering
/// a trailing `cleartomark` block when there is one, and `/Length2` the
/// remainder. A program with no `eexec` at all is entirely `/Length1`.
#[must_use]
pub fn font_file(bytes: &[u8]) -> FontFile {
    if bytes.first() == Some(&PFB_MARKER) {
        return pfb_font_file(bytes);
    }
    ascii_font_file(bytes)
}

/// Walk PFB records, concatenating their bodies and measuring each class.
///
/// Truncation is tolerated the way [`split_pfb`] tolerates it: a body whose
/// declared length overruns the blob contributes what is actually there, and
/// the walk stops. The invariant survives, because every byte counted is a
/// byte pushed.
fn pfb_font_file(bytes: &[u8]) -> FontFile {
    let mut out = FontFile {
        program: Vec::with_capacity(bytes.len()),
        length1: 0,
        length2: 0,
        length3: 0,
    };
    let mut seen_binary = false;
    let mut at = 0usize;
    while at < bytes.len() {
        let Some(header) = bytes.get(at..at.saturating_add(6)) else {
            break;
        };
        if header.first().copied() != Some(PFB_MARKER) {
            break;
        }
        let Some(k @ (PFB_TEXT | PFB_BINARY)) = header.get(1).copied() else {
            break;
        };
        let declared = le_u32(header.get(2..6).unwrap_or_default()) as usize;
        let body_at = at.saturating_add(6);
        let body = bytes
            .get(body_at..body_at.saturating_add(declared))
            .unwrap_or_else(|| bytes.get(body_at..).unwrap_or_default());
        let n = len_u32(body.len());
        out.program.extend_from_slice(body);
        if k == PFB_TEXT {
            if seen_binary {
                out.length3 = out.length3.saturating_add(n);
            } else {
                out.length1 = out.length1.saturating_add(n);
            }
        } else {
            seen_binary = true;
            out.length2 = out.length2.saturating_add(n);
        }
        at = body_at.saturating_add(body.len());
        if body.len() < declared {
            break;
        }
    }
    if out.program.is_empty() {
        // Not a walkable record chain after all — store what we were given
        // rather than an empty `/FontFile`, and describe it as clear text.
        return FontFile {
            program: bytes.to_vec(),
            length1: len_u32(bytes.len()),
            length2: 0,
            length3: 0,
        };
    }
    out
}

/// Measure an already-raw program: `eexec` splits `/Length1` from `/Length2`,
/// and a trailing zeros block splits `/Length3` off the end.
///
/// The encrypted portion is **not** decoded. A PFA writes it in hexadecimal,
/// and ISO 32000-1 §9.9 permits that in a `/FontFile` — the lengths describe
/// the stored bytes, so hex stays hex and `/Length2` counts hex digits.
fn ascii_font_file(bytes: &[u8]) -> FontFile {
    let Some(key) = find_eexec(bytes) else {
        return FontFile {
            program: bytes.to_vec(),
            length1: len_u32(bytes.len()),
            length2: 0,
            length3: 0,
        };
    };
    let trailer = trailer_start(bytes, key);
    FontFile {
        program: bytes.to_vec(),
        length1: len_u32(key),
        length2: len_u32(trailer.saturating_sub(key)),
        length3: len_u32(bytes.len().saturating_sub(trailer)),
    }
}

/// Where the fixed-content trailer begins: the first of the 512 ASCII `0`
/// digits that close a Type 1 program.
///
/// The Type 1 specification's trailer is exactly 512 zeros — conventionally
/// eight 64-digit lines — followed by `cleartomark`. Counting the *maximal*
/// trailing run of zeros and whitespace would be wrong: a private portion
/// whose last hex digits happen to be zeros would be eaten into `/Length3`.
/// So the count is exact, taken backwards from the last zero, and anything
/// but a 512-zero block means the program has no trailer and `/Length3` is 0.
fn trailer_start(bytes: &[u8], after: usize) -> usize {
    const TRAILER_ZEROS: usize = 512;
    let tail = bytes.get(after..).unwrap_or_default();
    // Walk back over `cleartomark` and its whitespace to the last zero.
    let mut end = tail.len();
    while end > 0 && tail.get(end.saturating_sub(1)) != Some(&b'0') {
        end = end.saturating_sub(1);
    }
    // Then back over exactly 512 zeros, tolerating the line breaks between.
    let mut zeros = 0usize;
    let mut at = end;
    while at > 0 && zeros < TRAILER_ZEROS {
        match tail.get(at.saturating_sub(1)) {
            Some(b'0') => zeros = zeros.saturating_add(1),
            Some(b) if b.is_ascii_whitespace() => {}
            _ => break,
        }
        at = at.saturating_sub(1);
    }
    if zeros == TRAILER_ZEROS {
        after.saturating_add(at)
    } else {
        bytes.len()
    }
}

fn len_u32(n: usize) -> u32 {
    u32::try_from(n).unwrap_or(u32::MAX)
}

/// Sniff the container and split the program.
///
/// Damage tolerance mirrors what a Type 1 rasterizer has to survive in the
/// wild: a PFB whose final segment length overruns the blob is truncated to
/// what is there, a missing type-3 terminator is not an error, and a PFA whose
/// hex runs into `0000…0000 cleartomark` simply stops at the first non-hex
/// byte. Each of those records a diagnostic.
///
/// # Errors
///
/// [`Error::Empty`] for an empty blob, [`Error::PfbSegment`] for a PFB whose
/// *first* segment header is unusable (past that point truncation is a
/// recovery, not a failure), and [`Error::NoEexec`] when no private portion can
/// be located at all.
pub fn split(bytes: &[u8], diags: &mut Diagnostics) -> Result<Split, Error> {
    if bytes.is_empty() {
        return Err(Error::Empty);
    }
    if bytes.first() == Some(&PFB_MARKER) {
        return split_pfb(bytes, diags);
    }
    let container = if banner(bytes) {
        Container::Pfa
    } else {
        Container::Bare
    };
    split_ascii(bytes, container, diags)
}

/// Whether the blob opens with one of the two ASCII Type 1 banners. The scan
/// tolerates leading whitespace, which real files do carry.
fn banner(bytes: &[u8]) -> bool {
    let start = bytes
        .iter()
        .position(|b| !b.is_ascii_whitespace())
        .unwrap_or(bytes.len());
    let rest = bytes.get(start..).unwrap_or_default();
    rest.starts_with(b"%!PS-AdobeFont") || rest.starts_with(b"%!FontType1")
}

/// Walk the `[0x80, type, len:u32le]` record chain.
fn split_pfb(bytes: &[u8], diags: &mut Diagnostics) -> Result<Split, Error> {
    let mut clear = Vec::new();
    let mut cipher = Vec::new();
    let mut at = 0usize;
    let mut first = true;

    while at < bytes.len() {
        let Some(header) = bytes.get(at..at.saturating_add(6)) else {
            // A trailing stub too short to be a header. Real files end on a
            // type-3 record; this one did not.
            diags.record(
                Severity::Suspicious,
                DiagKind::Type1PfbTruncated,
                Some(at as u64),
            );
            break;
        };
        let (marker, kind) = (header.first().copied(), header.get(1).copied());
        if marker != Some(PFB_MARKER) {
            if first {
                return Err(Error::PfbSegment { at });
            }
            diags.record(
                Severity::Suspicious,
                DiagKind::Type1PfbTruncated,
                Some(at as u64),
            );
            break;
        }
        match kind {
            Some(PFB_EOF) => break,
            Some(k @ (PFB_TEXT | PFB_BINARY)) => {
                let declared = le_u32(header.get(2..6).unwrap_or_default()) as usize;
                let body_at = at.saturating_add(6);
                let body = if let Some(b) = bytes.get(body_at..body_at.saturating_add(declared)) {
                    b
                } else {
                    // Length overruns the blob: keep what is there.
                    diags.record(
                        Severity::Recovered,
                        DiagKind::Type1PfbTruncated,
                        Some(at as u64),
                    );
                    bytes.get(body_at..).unwrap_or_default()
                };
                if k == PFB_TEXT {
                    // Only the preamble matters; the trailing 512 zeros and
                    // `cleartomark` are a PostScript ritual, not font data,
                    // and they arrive *after* the binary segments.
                    if cipher.is_empty() {
                        clear.extend_from_slice(body);
                    }
                } else {
                    cipher.extend_from_slice(body);
                }
                at = body_at.saturating_add(body.len());
                if body.len() < declared {
                    break;
                }
            }
            _ => {
                if first {
                    return Err(Error::PfbSegment { at });
                }
                diags.record(
                    Severity::Suspicious,
                    DiagKind::Type1PfbTruncated,
                    Some(at as u64),
                );
                break;
            }
        }
        first = false;
    }

    if cipher.is_empty() {
        // A PFB whose text segment nevertheless holds an inline `eexec`
        // section — malformed, but recoverable by reading it as PFA.
        if let Ok(mut ascii) = split_ascii(&clear, Container::Pfb, diags) {
            ascii.container = Container::Pfb;
            return Ok(ascii);
        }
        return Err(Error::NoEexec);
    }
    Ok(Split {
        container: Container::Pfb,
        clear,
        cipher,
    })
}

/// Find `eexec` in an ASCII program and take everything after it, hex-decoding
/// when the tail is hex.
fn split_ascii(
    bytes: &[u8],
    container: Container,
    diags: &mut Diagnostics,
) -> Result<Split, Error> {
    let key = find_eexec(bytes).ok_or(Error::NoEexec)?;
    let clear = bytes.get(..key).unwrap_or_default().to_vec();
    let tail = bytes.get(key..).unwrap_or_default();

    // The private portion is hex when its first four *significant* bytes are
    // all hex digits — the test FreeType uses, and it is reliable because a
    // binary section's first four bytes are random ciphertext.
    let significant: Vec<u8> = tail
        .iter()
        .copied()
        .filter(|b| !b.is_ascii_whitespace())
        .take(4)
        .collect();
    let is_hex = significant.len() == 4 && significant.iter().all(u8::is_ascii_hexdigit);

    let cipher = if is_hex {
        hex_decode(tail, diags)
    } else {
        tail.to_vec()
    };
    Ok(Split {
        container,
        clear,
        cipher,
    })
}

/// Locate the byte just past the `eexec` keyword and its following
/// end-of-line.
///
/// The keyword is matched only at a token boundary, so `eexec` inside a
/// comment or a `(string)` does not trigger. Exactly one EOL is consumed —
/// `\r\n`, `\r` or `\n` — plus any run of spaces or tabs before it, matching
/// what the Type 1 specification says the interpreter does.
fn find_eexec(bytes: &[u8]) -> Option<usize> {
    let mut i = 0usize;
    while i < bytes.len() {
        match bytes.get(i).copied() {
            // Skip a `%` comment to end of line.
            Some(b'%') => {
                while i < bytes.len() && !matches!(bytes.get(i), Some(b'\r' | b'\n')) {
                    i = i.saturating_add(1);
                }
            }
            // Skip a `(…)` string, honouring nesting and backslash escapes.
            Some(b'(') => {
                let mut depth = 1usize;
                i = i.saturating_add(1);
                while i < bytes.len() && depth > 0 {
                    match bytes.get(i).copied() {
                        Some(b'\\') => i = i.saturating_add(1),
                        Some(b'(') => depth = depth.saturating_add(1),
                        Some(b')') => depth = depth.saturating_sub(1),
                        _ => {}
                    }
                    i = i.saturating_add(1);
                }
            }
            _ => {
                if bytes.get(i..i.saturating_add(5)) == Some(b"eexec".as_slice())
                    && before_is_boundary(bytes, i)
                    && after_is_boundary(bytes, i.saturating_add(5))
                {
                    return Some(skip_one_eol(bytes, i.saturating_add(5)));
                }
                i = i.saturating_add(1);
            }
        }
    }
    None
}

fn before_is_boundary(bytes: &[u8], at: usize) -> bool {
    at == 0
        || at
            .checked_sub(1)
            .and_then(|p| bytes.get(p))
            .is_some_and(|b| b.is_ascii_whitespace() || *b == b'/')
}

fn after_is_boundary(bytes: &[u8], at: usize) -> bool {
    bytes.get(at).is_none_or(u8::is_ascii_whitespace)
}

/// Consume trailing blanks then exactly one line ending.
fn skip_one_eol(bytes: &[u8], mut at: usize) -> usize {
    while matches!(bytes.get(at), Some(b' ' | b'\t')) {
        at = at.saturating_add(1);
    }
    match bytes.get(at) {
        Some(b'\r') => {
            at = at.saturating_add(1);
            if bytes.get(at) == Some(&b'\n') {
                at = at.saturating_add(1);
            }
        }
        Some(b'\n') => at = at.saturating_add(1),
        _ => {}
    }
    at
}

/// Decode hex until the first byte that is neither a hex digit nor whitespace.
fn hex_decode(bytes: &[u8], diags: &mut Diagnostics) -> Vec<u8> {
    let mut out = Vec::with_capacity(bytes.len() / 2);
    let mut high: Option<u8> = None;
    for (i, b) in bytes.iter().enumerate() {
        if b.is_ascii_whitespace() {
            continue;
        }
        let Some(nibble) = hex_digit(*b) else {
            if i.saturating_add(1) < bytes.len() {
                diags.record(
                    Severity::Recovered,
                    DiagKind::Type1HexTruncated,
                    Some(i as u64),
                );
            }
            break;
        };
        match high.take() {
            None => high = Some(nibble),
            Some(h) => out.push((h << 4) | nibble),
        }
    }
    out
}

fn le_u32(b: &[u8]) -> u32 {
    let g = |i: usize| u32::from(b.get(i).copied().unwrap_or(0));
    g(0) | (g(1) << 8) | (g(2) << 16) | (g(3) << 24)
}

#[cfg(test)]
#[allow(
    clippy::indexing_slicing,
    clippy::float_cmp,
    clippy::cast_possible_truncation,
    clippy::cast_sign_loss,
    clippy::similar_names
)]
mod tests {
    use super::{Container, split};
    use pdfrum_common::{DiagKind, Diagnostics};

    /// A minimal PFB: text segment, binary segment, EOF.
    fn pfb(text: &[u8], binary: &[u8]) -> Vec<u8> {
        let mut v = vec![0x80, 1];
        v.extend_from_slice(&(text.len() as u32).to_le_bytes());
        v.extend_from_slice(text);
        v.extend_from_slice(&[0x80, 2]);
        v.extend_from_slice(&(binary.len() as u32).to_le_bytes());
        v.extend_from_slice(binary);
        v.extend_from_slice(&[0x80, 3]);
        v
    }

    #[test]
    fn pfb_and_pfa_agree() {
        let mut d = Diagnostics::default();
        let clear = b"%!PS-AdobeFont-1.0: T 1\n/FontName /T def\ncurrentfile eexec\n";
        let binary = b"\x01\x02\x03\x04rest-of-the-private-dict";

        let from_pfb = split(&pfb(clear, binary), &mut d).unwrap();
        assert_eq!(from_pfb.container, Container::Pfb);
        assert_eq!(from_pfb.clear, clear);
        assert_eq!(from_pfb.cipher, binary);

        // The same font written as PFA: the binary section spelled in hex.
        let mut pfa = clear.to_vec();
        for b in binary {
            pfa.extend_from_slice(format!("{b:02X}").as_bytes());
        }
        let from_pfa = split(&pfa, &mut d).unwrap();
        assert_eq!(from_pfa.container, Container::Pfa);
        assert_eq!(from_pfa.clear, clear);
        assert_eq!(from_pfa.cipher, binary);
    }

    #[test]
    fn truncated_pfb_segment_keeps_what_it_has() {
        // Eat the two-byte EOF record and four bytes of the binary payload,
        // so the declared length of 8 overruns what is there.
        let mut good = pfb(b"%!PS-AdobeFont\n", b"abcdefgh");
        good.truncate(good.len() - 6);
        let mut d = Diagnostics::default();
        let s = split(&good, &mut d).unwrap();
        assert_eq!(s.cipher, b"abcd");
        assert!(d.contains(&DiagKind::Type1PfbTruncated));
    }

    #[test]
    fn bare_program_reads_as_pfa_shaped() {
        let mut d = Diagnostics::default();
        let s = split(
            b"/FontName /T def\ncurrentfile eexec\n\x01\x02\x03\x04tail",
            &mut d,
        )
        .unwrap();
        assert_eq!(s.container, Container::Bare);
        assert_eq!(s.cipher, b"\x01\x02\x03\x04tail");
    }

    #[test]
    fn eexec_in_a_comment_or_string_is_not_the_keyword() {
        let mut d = Diagnostics::default();
        // The payload's first four bytes are not all hex digits, so it is read
        // as binary rather than hex-decoded.
        let s = split(
            b"%!PS-AdobeFont\n% eexec here\n(eexec there) def\ncurrentfile eexec\r\n\x01\x02\x03\x04real",
            &mut d,
        )
        .unwrap();
        assert_eq!(s.cipher, b"\x01\x02\x03\x04real");
        assert!(s.clear.ends_with(b"eexec\r\n"));
    }

    /// The partition ISO 32000-1 §9.9 table 127 asks for, on the wrapper that
    /// breaks it: a PFB's framing is 6 bytes per record plus a 2-byte end
    /// marker, and none of it is font data.
    #[test]
    fn pfb_font_file_drops_the_framing_and_partitions_what_is_left() {
        let clear = b"%!PS-AdobeFont-1.0: T 1\ncurrentfile eexec\n";
        let binary = b"\x01\x02\x03\x04private";
        let mut wrapped = pfb(clear, binary);
        // The trailer PFB files carry after the binary: a text record holding
        // the 512 zeros and `cleartomark`.
        let trailer = {
            let mut t = vec![b'0'; 512];
            t.extend_from_slice(b"\ncleartomark\n");
            t
        };
        wrapped.truncate(wrapped.len() - 2); // drop the 0x80 0x03 marker
        wrapped.extend_from_slice(&[0x80, 1]);
        wrapped.extend_from_slice(&(trailer.len() as u32).to_le_bytes());
        wrapped.extend_from_slice(&trailer);
        wrapped.extend_from_slice(&[0x80, 3]);

        let file = super::font_file(&wrapped);
        assert_eq!(
            file.program.len() as u32,
            file.length1 + file.length2 + file.length3,
            "the three lengths must partition the stored program"
        );
        assert!(file.program.starts_with(b"%!"));
        assert_eq!(file.length1 as usize, clear.len());
        assert_eq!(file.length2 as usize, binary.len());
        assert_eq!(file.length3 as usize, trailer.len());
        assert_eq!(&file.program[..clear.len()], clear);
        assert_eq!(
            &file.program[clear.len()..clear.len() + binary.len()],
            binary
        );
        // 20 bytes of framing — three 6-byte headers and the 2-byte end
        // marker — are gone.
        assert_eq!(file.program.len() + 20, wrapped.len());
    }

    /// A PFA has no wrapper: it is stored as-is, hex private portion included,
    /// with the lengths measured off the `eexec` boundary and the trailer.
    #[test]
    fn pfa_font_file_is_stored_as_is_with_hex_kept_hex() {
        let mut pfa = b"%!PS-AdobeFont-1.0: T 1\ncurrentfile eexec\n".to_vec();
        let head = pfa.len();
        pfa.extend_from_slice(b"41424344454647484950\n");
        let cipher = pfa.len() - head;
        let mut trailer = vec![b'0'; 512];
        trailer.extend_from_slice(b"\ncleartomark\n");
        pfa.extend_from_slice(&trailer);

        let file = super::font_file(&pfa);
        assert_eq!(file.program, pfa, "a raw program is stored unchanged");
        assert_eq!(
            file.program.len() as u32,
            file.length1 + file.length2 + file.length3
        );
        assert_eq!(file.length1 as usize, head);
        assert_eq!(file.length2 as usize, cipher);
        assert_eq!(file.length3 as usize, trailer.len());
    }

    /// No trailer, no `/Length3`: the partition still holds, with the
    /// encrypted portion running to the end.
    #[test]
    fn a_program_without_a_trailer_has_length3_zero() {
        let raw = b"%!FontType1\ncurrentfile eexec\n\x01\x02\x03\x04tail";
        let file = super::font_file(raw);
        assert_eq!(file.length3, 0);
        assert_eq!(
            file.program.len() as u32,
            file.length1 + file.length2 + file.length3
        );
        assert_eq!(file.program, raw);
    }

    /// Bytes with no `eexec` at all are still stored and still partitioned —
    /// as one clear-text portion, which is the only honest reading.
    #[test]
    fn a_program_without_eexec_is_all_length1() {
        let file = super::font_file(b"not a font");
        assert_eq!(file.length1, 10);
        assert_eq!((file.length2, file.length3), (0, 0));
        assert_eq!(file.program, b"not a font");
    }

    /// A truncated PFB keeps what it has, and the invariant survives: every
    /// byte counted is a byte pushed.
    #[test]
    fn truncated_pfb_font_file_still_partitions() {
        let mut good = pfb(b"%!PS-AdobeFont\ncurrentfile eexec\n", b"abcdefgh");
        good.truncate(good.len() - 6);
        let file = super::font_file(&good);
        assert_eq!(
            file.program.len() as u32,
            file.length1 + file.length2 + file.length3
        );
        assert_eq!(file.length2, 4);
    }

    #[test]
    fn hex_stops_at_the_first_non_hex_byte() {
        let mut d = Diagnostics::default();
        let s = split(b"%!FontType1\neexec\n4142 4344 zz9999", &mut d).unwrap();
        assert_eq!(s.cipher, b"ABCD");
        assert!(d.contains(&DiagKind::Type1HexTruncated));
    }
}