v0.11.21: multi-pass rip — Disc::copy + Disc::patch + mapfile module

New primitives for two-stage rip workflows: fast forward pass with
zero-fill on failures, then targeted retries of bad ranges via a
ddrescue-compatible mapfile.

- Disc::copy now takes &CopyOptions (breaking change from positional
  args). Always writes a sidecar .mapfile. Opt-in skip_on_error +
  skip_forward give ddrescue-style fast sweep: 64 KB blocks,
  exponential skip-forward on failure, zero-fill bad blocks. Defaults
  preserve pre-0.11.21 behavior (recovery reads, abort on bad sector).

- Disc::patch is new and idempotent. Reads the mapfile, re-reads every
  non-finished range with full drive recovery, patches good bytes back
  into the ISO at exact offsets. Call N times for N retry attempts.

- disc::mapfile is a new module. ddrescue text format, crash-safe
  (flushed on every record()), greppable, human-editable, tool-compatible.
  Status chars match ddrescue: ? / * / / / - / +.

- Re-exports FileSectorReader from the crate root.

- freemkv CLI caller (pipe.rs) updated to the new Disc::copy signature
  in lockstep — shipped in the 0.11.21 freemkv CLI release.

Part of the 0.11.21 ecosystem sync (libfreemkv + freemkv + bdemu +
autorip all on 0.11.21).

CHANGELOG.md

@@ -1,5 +1,22 @@
 # Changelog
 
+## 0.11.21 (2026-04-24)
+
+### Multi-pass rip architecture — disc → ISO → patch → ISO
+
+New primitives for two-stage rip: fast forward pass with zero-fill on failures, then targeted retries of bad ranges. Keeps the library API stream-based; the multi-pass model lives entirely in caller-orchestrated function composition.
+
+- **New `Disc::copy(reader, path, &CopyOptions)`** replaces the positional-arg version. Always produces a ddrescue-format mapfile at `path + ".mapfile"` as a side-effect. With `skip_on_error=true` + `skip_forward=true`, does ddrescue-style fast sweep: 64 KB block reads, exponential skip-forward (256 KB → cap at 1% of disc) on failure, zero-fill bad blocks, record ranges in the mapfile. With defaults (both false), matches pre-0.11.21 behavior — uses drive-level recovery, aborts on bad sector. Mapfile is produced either way.
+- **New `Disc::patch(reader, path, &PatchOptions)`** — idempotent retry pass. Reads the mapfile, re-reads every non-`+` range with full drive recovery enabled, writes successful bytes back into the ISO at exact offsets, updates mapfile. Call N times for N retry attempts.
+- **New `disc::mapfile` module** — ddrescue-compatible plain-text format. Crash-safe (flushes on every `record()`), greppable, human-editable, tool-interoperable. Status chars match ddrescue: `?` non-tried · `*` non-trimmed · `/` non-scraped · `-` unreadable · `+` finished.
+- **Re-exports:** `FileSectorReader` from the crate root for ISO readers.
+
+### Breaking changes
+- `Disc::copy`'s signature changes from positional args (`decrypt, resume, batch, on_progress`) to `CopyOptions`. Previous callers must migrate. `freemkv` CLI updated in lockstep.
+
+### Version sync
+- Part of the 0.11.21 ecosystem release (libfreemkv + freemkv + bdemu + autorip all on 0.11.21).
+
 ## 0.11.18 (2026-04-24)
 
 ### DiscStream halt flag — Stop works during dense bad-sector regions

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "libfreemkv"
-version = "0.11.18"
+version = "0.11.21"
 edition = "2021"
 rust-version = "1.86"
 license = "AGPL-3.0-only"

src/disc/mapfile.rs

@@ -0,0 +1,422 @@
+//! ddrescue-compatible mapfile for tracking rip progress.
+//!
+//! Records which byte ranges of a disc image are good, unreadable,
+//! or not-yet-attempted. Written as plain text so it's greppable,
+//! human-editable, and interoperates with ddrescue's own tools.
+//!
+//! Format:
+//! ```text
+//! # Rescue Logfile. Created by libfreemkv v0.11.21
+//! # Current pos / status / pass / pass_time (ddrescue state machine — we only populate pos)
+//! 0x000000000  ?  1  0
+//! #      pos        size  status
+//! 0x000000000  0x12345678    +
+//! 0x012345678  0x00001000    -
+//! 0x012346678  0x01234500    ?
+//! ```
+//!
+//! Status chars: `?` non-tried · `*` non-trimmed · `/` non-scraped · `-` unreadable · `+` finished.
+//!
+//! The mapfile is flushed to disk on every `record()` call so a crashed
+//! rip loses at most one block of recorded state.
+
+use std::io::{self, Write};
+use std::path::{Path, PathBuf};
+
+/// Status of a byte range in the mapfile. ddrescue-compatible.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum SectorStatus {
+    /// `?` — not yet attempted. Initial state for a fresh mapfile.
+    NonTried,
+    /// `*` — fast-pass read failed; edges need trimming.
+    NonTrimmed,
+    /// `/` — trimmed; interior needs sector scrape.
+    NonScraped,
+    /// `-` — drive couldn't read it this session.
+    Unreadable,
+    /// `+` — good.
+    Finished,
+}
+
+impl SectorStatus {
+    pub fn to_char(self) -> char {
+        match self {
+            Self::NonTried => '?',
+            Self::NonTrimmed => '*',
+            Self::NonScraped => '/',
+            Self::Unreadable => '-',
+            Self::Finished => '+',
+        }
+    }
+    pub fn from_char(c: char) -> Option<Self> {
+        Some(match c {
+            '?' => Self::NonTried,
+            '*' => Self::NonTrimmed,
+            '/' => Self::NonScraped,
+            '-' => Self::Unreadable,
+            '+' => Self::Finished,
+            _ => return None,
+        })
+    }
+}
+
+/// One contiguous range of bytes with a status.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct MapEntry {
+    pub pos: u64,
+    pub size: u64,
+    pub status: SectorStatus,
+}
+
+/// Summary statistics over all entries.
+#[derive(Debug, Clone, Copy, Default)]
+pub struct MapStats {
+    pub bytes_total: u64,
+    pub bytes_good: u64,
+    pub bytes_unreadable: u64,
+    pub bytes_pending: u64,
+}
+
+/// Write-through mapfile. Every `record()` persists to disk immediately
+/// so a crash during rip loses at most one block.
+pub struct Mapfile {
+    path: PathBuf,
+    entries: Vec<MapEntry>,
+    total_size: u64,
+    version: String,
+}
+
+impl Mapfile {
+    /// Create a new mapfile with one `NonTried` region covering the whole disc.
+    /// Writes to disk immediately so a resume can pick up even if the caller
+    /// never records anything.
+    pub fn create(path: &Path, total_size: u64, version: &str) -> io::Result<Self> {
+        let mf = Self {
+            path: path.to_path_buf(),
+            entries: vec![MapEntry {
+                pos: 0,
+                size: total_size,
+                status: SectorStatus::NonTried,
+            }],
+            total_size,
+            version: version.to_string(),
+        };
+        mf.write_to_disk()?;
+        Ok(mf)
+    }
+
+    /// Load an existing mapfile from disk.
+    pub fn load(path: &Path) -> io::Result<Self> {
+        let text = std::fs::read_to_string(path)?;
+        let mut entries = Vec::new();
+        let mut saw_current_line = false;
+        let mut version = String::from("unknown");
+        for line in text.lines() {
+            let t = line.trim();
+            if t.is_empty() {
+                continue;
+            }
+            if let Some(rest) = t.strip_prefix('#') {
+                let rest = rest.trim();
+                if let Some(v) = rest.strip_prefix("Rescue Logfile. Created by ") {
+                    version = v.to_string();
+                }
+                continue;
+            }
+            // First non-comment line is the "current" state line (pos status [pass] [pass_time]).
+            // We ignore its contents but skip over it.
+            if !saw_current_line {
+                saw_current_line = true;
+                // But if the line looks like an entry (has at least 3 fields starting 0x...),
+                // it's probably actually an entry for a mapfile we wrote without a current line.
+                // Heuristic: current line has status char as 2nd field; entry has size as 2nd field.
+                let fields: Vec<&str> = t.split_whitespace().collect();
+                if fields.len() >= 3 && fields[1].starts_with("0x") {
+                    // It's an entry, not a current line — fall through to entry parse.
+                } else {
+                    continue;
+                }
+            }
+            // Entry: `pos size statuschar`
+            let fields: Vec<&str> = t.split_whitespace().collect();
+            if fields.len() < 3 {
+                continue;
+            }
+            let pos = parse_hex(fields[0])?;
+            let size = parse_hex(fields[1])?;
+            let status = fields[2]
+                .chars()
+                .next()
+                .and_then(SectorStatus::from_char)
+                .ok_or_else(|| {
+                    io::Error::new(
+                        io::ErrorKind::InvalidData,
+                        format!("bad status char in mapfile: {}", fields[2]),
+                    )
+                })?;
+            entries.push(MapEntry { pos, size, status });
+        }
+        entries.sort_by_key(|e| e.pos);
+        let total_size = entries.last().map(|e| e.pos + e.size).unwrap_or(0);
+        Ok(Self {
+            path: path.to_path_buf(),
+            entries,
+            total_size,
+            version,
+        })
+    }
+
+    /// Load if the file exists, otherwise create a fresh mapfile.
+    pub fn open_or_create(path: &Path, total_size: u64, version: &str) -> io::Result<Self> {
+        match Self::load(path) {
+            Ok(mf) => Ok(mf),
+            Err(e) if e.kind() == io::ErrorKind::NotFound => Self::create(path, total_size, version),
+            Err(e) => Err(e),
+        }
+    }
+
+    /// Mark a byte range as having the given status. Splits any overlapping
+    /// existing entries, merges with adjacent same-status entries, and flushes
+    /// to disk.
+    pub fn record(&mut self, pos: u64, size: u64, status: SectorStatus) -> io::Result<()> {
+        if size == 0 {
+            return Ok(());
+        }
+        let end = pos.saturating_add(size);
+        let mut new_entries = Vec::with_capacity(self.entries.len() + 2);
+
+        for e in self.entries.drain(..) {
+            let e_end = e.pos + e.size;
+            if e_end <= pos || e.pos >= end {
+                // entirely before or after — keep
+                new_entries.push(e);
+                continue;
+            }
+            // Overlap — keep portions outside [pos, end)
+            if e.pos < pos {
+                new_entries.push(MapEntry {
+                    pos: e.pos,
+                    size: pos - e.pos,
+                    status: e.status,
+                });
+            }
+            if e_end > end {
+                new_entries.push(MapEntry {
+                    pos: end,
+                    size: e_end - end,
+                    status: e.status,
+                });
+            }
+        }
+        new_entries.push(MapEntry { pos, size, status });
+        new_entries.sort_by_key(|e| e.pos);
+
+        // Coalesce adjacent same-status entries.
+        let mut merged: Vec<MapEntry> = Vec::with_capacity(new_entries.len());
+        for e in new_entries {
+            if let Some(last) = merged.last_mut() {
+                if last.pos + last.size == e.pos && last.status == e.status {
+                    last.size += e.size;
+                    continue;
+                }
+            }
+            merged.push(e);
+        }
+
+        self.entries = merged;
+        self.write_to_disk()?;
+        Ok(())
+    }
+
+    pub fn entries(&self) -> &[MapEntry] {
+        &self.entries
+    }
+
+    pub fn total_size(&self) -> u64 {
+        self.total_size
+    }
+
+    /// First range with a given status starting at or after `from`.
+    pub fn next_with(&self, from: u64, status: SectorStatus) -> Option<(u64, u64)> {
+        for e in &self.entries {
+            if e.status != status {
+                continue;
+            }
+            let e_end = e.pos + e.size;
+            if e_end <= from {
+                continue;
+            }
+            let start = e.pos.max(from);
+            return Some((start, e_end - start));
+        }
+        None
+    }
+
+    /// All ranges matching one of the given statuses, in position order.
+    pub fn ranges_with(&self, statuses: &[SectorStatus]) -> Vec<(u64, u64)> {
+        self.entries
+            .iter()
+            .filter(|e| statuses.contains(&e.status))
+            .map(|e| (e.pos, e.size))
+            .collect()
+    }
+
+    pub fn stats(&self) -> MapStats {
+        let mut s = MapStats {
+            bytes_total: self.total_size,
+            ..Default::default()
+        };
+        for e in &self.entries {
+            match e.status {
+                SectorStatus::Finished => s.bytes_good += e.size,
+                SectorStatus::Unreadable => s.bytes_unreadable += e.size,
+                SectorStatus::NonTried | SectorStatus::NonTrimmed | SectorStatus::NonScraped => {
+                    s.bytes_pending += e.size
+                }
+            }
+        }
+        s
+    }
+
+    fn write_to_disk(&self) -> io::Result<()> {
+        // Write to a tempfile then rename for atomicity. Appending ".tmp"
+        // rather than `with_extension` so we don't clobber the original
+        // extension (which may already be ".mapfile").
+        let tmp = {
+            let mut s = self.path.clone().into_os_string();
+            s.push(".tmp");
+            PathBuf::from(s)
+        };
+        {
+            let file = std::fs::File::create(&tmp)?;
+            let mut w = std::io::BufWriter::new(file);
+            writeln!(w, "# Rescue Logfile. Created by libfreemkv v{}", self.version)?;
+            writeln!(w, "# Current pos / status / pass / pass_time")?;
+            writeln!(w, "0x000000000  ?  1  0")?;
+            writeln!(w, "#      pos        size  status")?;
+            for e in &self.entries {
+                writeln!(w, "0x{:09x}  0x{:09x}    {}", e.pos, e.size, e.status.to_char())?;
+            }
+            w.flush()?;
+        }
+        std::fs::rename(&tmp, &self.path)?;
+        Ok(())
+    }
+}
+
+fn parse_hex(s: &str) -> io::Result<u64> {
+    let s = s.strip_prefix("0x").unwrap_or(s);
+    u64::from_str_radix(s, 16)
+        .map_err(|e| io::Error::new(io::ErrorKind::InvalidData, format!("bad hex {s}: {e}")))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn tmpfile(tag: &str) -> PathBuf {
+        use std::sync::atomic::{AtomicU64, Ordering};
+        static CTR: AtomicU64 = AtomicU64::new(0);
+        let n = CTR.fetch_add(1, Ordering::Relaxed);
+        let name = format!(
+            "libfreemkv-mapfile-test-{}-{}-{}.mapfile",
+            std::process::id(),
+            tag,
+            n
+        );
+        std::env::temp_dir().join(name)
+    }
+
+    #[test]
+    fn create_has_one_nontried_region() {
+        let p = tmpfile("create_has_one_nontried_region");
+        let _ = std::fs::remove_file(&p);
+        let mf = Mapfile::create(&p, 1000, "test").unwrap();
+        assert_eq!(mf.entries().len(), 1);
+        assert_eq!(mf.entries()[0].pos, 0);
+        assert_eq!(mf.entries()[0].size, 1000);
+        assert_eq!(mf.entries()[0].status, SectorStatus::NonTried);
+        let _ = std::fs::remove_file(&p);
+    }
+
+    #[test]
+    fn record_splits_overlap() {
+        let p = tmpfile("record_splits_overlap");
+        let _ = std::fs::remove_file(&p);
+        let mut mf = Mapfile::create(&p, 1000, "test").unwrap();
+        mf.record(200, 100, SectorStatus::Finished).unwrap();
+        let es = mf.entries();
+        assert_eq!(es.len(), 3);
+        assert_eq!((es[0].pos, es[0].size, es[0].status), (0, 200, SectorStatus::NonTried));
+        assert_eq!((es[1].pos, es[1].size, es[1].status), (200, 100, SectorStatus::Finished));
+        assert_eq!((es[2].pos, es[2].size, es[2].status), (300, 700, SectorStatus::NonTried));
+        let _ = std::fs::remove_file(&p);
+    }
+
+    #[test]
+    fn record_coalesces_adjacent_same_status() {
+        let p = tmpfile("record_coalesces_adjacent_same_status");
+        let _ = std::fs::remove_file(&p);
+        let mut mf = Mapfile::create(&p, 1000, "test").unwrap();
+        mf.record(100, 100, SectorStatus::Finished).unwrap();
+        mf.record(200, 100, SectorStatus::Finished).unwrap();
+        // Entries: [0..100 NonTried, 100..300 Finished (merged), 300..1000 NonTried]
+        let es = mf.entries();
+        assert_eq!(es.len(), 3);
+        assert_eq!((es[1].pos, es[1].size, es[1].status), (100, 200, SectorStatus::Finished));
+        let _ = std::fs::remove_file(&p);
+    }
+
+    #[test]
+    fn record_replaces_existing_status() {
+        let p = tmpfile("record_replaces_existing_status");
+        let _ = std::fs::remove_file(&p);
+        let mut mf = Mapfile::create(&p, 1000, "test").unwrap();
+        mf.record(200, 100, SectorStatus::Unreadable).unwrap();
+        mf.record(200, 100, SectorStatus::Finished).unwrap();
+        let es = mf.entries();
+        // The overwrite should result in all finished at 200..300, NonTried elsewhere — 3 entries.
+        assert_eq!(es.len(), 3);
+        assert_eq!(es[1].status, SectorStatus::Finished);
+        let _ = std::fs::remove_file(&p);
+    }
+
+    #[test]
+    fn round_trip_load() {
+        let p = tmpfile("round_trip_load");
+        let _ = std::fs::remove_file(&p);
+        let mut mf = Mapfile::create(&p, 1000, "test").unwrap();
+        mf.record(100, 200, SectorStatus::Finished).unwrap();
+        mf.record(500, 100, SectorStatus::Unreadable).unwrap();
+        let loaded = Mapfile::load(&p).unwrap();
+        assert_eq!(loaded.entries(), mf.entries());
+        let _ = std::fs::remove_file(&p);
+    }
+
+    #[test]
+    fn stats_sum_correctly() {
+        let p = tmpfile("stats_sum_correctly");
+        let _ = std::fs::remove_file(&p);
+        let mut mf = Mapfile::create(&p, 1000, "test").unwrap();
+        mf.record(0, 400, SectorStatus::Finished).unwrap();
+        mf.record(400, 100, SectorStatus::Unreadable).unwrap();
+        let s = mf.stats();
+        assert_eq!(s.bytes_good, 400);
+        assert_eq!(s.bytes_unreadable, 100);
+        assert_eq!(s.bytes_pending, 500);
+        assert_eq!(s.bytes_total, 1000);
+        let _ = std::fs::remove_file(&p);
+    }
+
+    #[test]
+    fn ranges_with_filters() {
+        let p = tmpfile("ranges_with_filters");
+        let _ = std::fs::remove_file(&p);
+        let mut mf = Mapfile::create(&p, 1000, "test").unwrap();
+        mf.record(100, 50, SectorStatus::Unreadable).unwrap();
+        mf.record(300, 50, SectorStatus::Unreadable).unwrap();
+        let bad = mf.ranges_with(&[SectorStatus::Unreadable]);
+        assert_eq!(bad, vec![(100, 50), (300, 50)]);
+        let _ = std::fs::remove_file(&p);
+    }
+}

src/disc/mod.rs

@@ -11,6 +11,7 @@
 mod bluray;
 mod dvd;
 mod encrypt;
+pub mod mapfile;
 
 use crate::drive::Drive;
 use crate::error::{Error, Result};
@@ -1206,94 +1207,333 @@ impl Disc {
 
     /// Raw sector copy — write the entire disc image to a file.
     ///
-    /// This is NOT a stream operation. It copies sectors 0→capacity byte-for-byte,
+    /// NOT a stream operation. Copies sectors 0→capacity byte-for-byte producing
-    /// producing a valid ISO/UDF image. The disc's filesystem structure is preserved.
+    /// a valid ISO/UDF image. Records progress in a ddrescue-format mapfile at
+    /// `path + ".mapfile"` — flushed every block for crash-safe resume.
     ///
-    /// If `decrypt` is true and keys are available, sectors are decrypted on the fly.
+    /// # Options
-    /// If `resume` is true and the file already exists, resumes from the last safe position.
+    /// - **default** (all false): behavior matches pre-v0.11.21 — uses full
-    ///
+    ///   drive recovery (may take minutes per bad sector), aborts on error.
-    /// `on_progress` is called periodically with (bytes_done, total_bytes).
+    ///   Mapfile is produced as a side-effect.
+    /// - **skip_on_error**: zero-fill bad blocks in the ISO, mark them in the
+    ///   mapfile, and continue. Uses fast reads (no drive-level recovery loop).
+    /// - **skip_forward** (implies skip_on_error): on block failure, also skip
+    ///   forward by an exponentially-growing amount, marking the jumped region
+    ///   as `non-trimmed` for later trimming/scraping by `Disc::patch`.
+    /// - **resume**: if the mapfile exists, resume from its state — only
+    ///   `non-tried` ranges are read. Without `resume`, a fresh mapfile is
+    ///   written and the ISO recreated from scratch.
     pub fn copy(
         &self,
         reader: &mut dyn SectorReader,
         path: &std::path::Path,
-        decrypt: bool,
+        opts: &CopyOptions,
-        resume: bool,
+    ) -> Result<CopyResult> {
-        batch_sectors: Option<u16>,
-        on_progress: Option<&dyn Fn(u64, u64)>,
-    ) -> Result<()> {
         use std::io::{Seek, SeekFrom, Write};
 
         let total_bytes = self.capacity_sectors as u64 * 2048;
-        let keys = if decrypt {
+        let keys = if opts.decrypt {
             self.decrypt_keys()
         } else {
             crate::decrypt::DecryptKeys::None
         };
 
-        // Resume: check existing file
+        // Mapfile: load if resuming, else wipe + recreate.
-        let (start_lba, file) = if resume {
+        let mapfile_path = mapfile_path_for(path);
-            match std::fs::metadata(path) {
+        if !opts.resume {
-                Ok(meta) if meta.len() > 0 => {
+            let _ = std::fs::remove_file(&mapfile_path);
-                    let safe_sectors = (meta.len() / 2048).saturating_sub(5) as u32;
+        }
-                    let mut f = std::fs::OpenOptions::new()
+        let mut map = mapfile::Mapfile::open_or_create(&mapfile_path, total_bytes, env!("CARGO_PKG_VERSION"))
+            .map_err(|e| Error::IoError { source: e })?;
+
+        // ISO file: if resuming and mapfile has Finished ranges, open existing;
+        // otherwise create fresh and pre-size to total_bytes (sparse holes for
+        // non-tried regions).
+        let file = if opts.resume && std::fs::metadata(path).map(|m| m.len() > 0).unwrap_or(false) {
+            std::fs::OpenOptions::new()
+                .write(true)
+                .open(path)
+                .map_err(|e| Error::IoError { source: e })?
+        } else {
+            let f = std::fs::File::create(path).map_err(|e| Error::IoError { source: e })?;
+            f.set_len(total_bytes).map_err(|e| Error::IoError { source: e })?;
+            f
+        };
+
+        let mut file = file;
+        let batch: u16 = match opts.batch_sectors {
+            Some(b) => b,
+            None if opts.skip_forward => 32, // 64 KB = BD ECC block size
+            None => DEFAULT_BATCH_SECTORS,
+        };
+
+        // Skip-forward state.
+        let skip_init = 256 * 1024u64; // 256 KB
+        let skip_max = (total_bytes / 100).max(skip_init); // cap at 1% of disc
+        let mut skip_size = skip_init;
+
+        let mut buf = vec![0u8; batch as usize * 2048];
+        let mut bytes_done = 0u64;
+        let mut halt_requested = false;
+
+        // Iterate over not-yet-finished regions from the mapfile. We re-read the
+        // mapfile after each block because record() mutates the region list.
+        'outer: loop {
+            let regions_to_do = map.ranges_with(&[
+                mapfile::SectorStatus::NonTried,
+                mapfile::SectorStatus::NonTrimmed,
+                mapfile::SectorStatus::NonScraped,
+            ]);
+            if regions_to_do.is_empty() {
+                break;
+            }
+            // Only process the first NonTried range per outer pass; skip_forward
+            // may turn others into NonTrimmed which we DO NOT re-enter here —
+            // Disc::patch handles those.
+            let Some((region_pos, region_size)) = map
+                .next_with(0, mapfile::SectorStatus::NonTried)
+            else {
+                break;
+            };
+            let region_end = region_pos + region_size;
+            let mut pos = region_pos;
+
+            while pos < region_end {
+                if let Some(ref h) = opts.halt {
+                    if h.load(std::sync::atomic::Ordering::Relaxed) {
+                        halt_requested = true;
+                        break 'outer;
+                    }
+                }
+                let block_bytes = (region_end - pos).min(batch as u64 * 2048);
+                let lba = (pos / 2048) as u32;
+                let count = (block_bytes / 2048) as u16;
+                let bytes = count as usize * 2048;
+
+                let recovery = !opts.skip_on_error; // fast reads when skipping
+                let read_ok = reader
+                    .read_sectors(lba, count, &mut buf[..bytes], recovery)
+                    .is_ok();
+
+                if read_ok {
+                    if opts.decrypt {
+                        crate::decrypt::decrypt_sectors(&mut buf[..bytes], &keys, 0)?;
+                    }
+                    file.seek(SeekFrom::Start(pos)).map_err(|e| Error::IoError { source: e })?;
+                    file.write_all(&buf[..bytes]).map_err(|e| Error::IoError { source: e })?;
+                    map.record(pos, block_bytes, mapfile::SectorStatus::Finished)
+                        .map_err(|e| Error::IoError { source: e })?;
+                    bytes_done = bytes_done.saturating_add(block_bytes);
+                    skip_size = skip_init; // reset after success
+                    pos += block_bytes;
+                } else if opts.skip_on_error {
+                    // Zero-fill this block, mark non-trimmed for later patch trim.
+                    buf[..bytes].fill(0);
+                    file.seek(SeekFrom::Start(pos)).map_err(|e| Error::IoError { source: e })?;
+                    file.write_all(&buf[..bytes]).map_err(|e| Error::IoError { source: e })?;
+                    map.record(pos, block_bytes, mapfile::SectorStatus::NonTrimmed)
+                        .map_err(|e| Error::IoError { source: e })?;
+                    pos += block_bytes;
+
+                    if opts.skip_forward && pos < region_end {
+                        // Skip ahead; mark skipped bytes as non-trimmed too.
+                        let jump = skip_size.min(region_end - pos);
+                        if jump > 0 {
+                            map.record(pos, jump, mapfile::SectorStatus::NonTrimmed)
+                                .map_err(|e| Error::IoError { source: e })?;
+                            pos += jump;
+                        }
+                        skip_size = (skip_size * 2).min(skip_max);
+                    }
+                } else {
+                    // Current behavior (pre-0.11.21): abort on first bad sector.
+                    return Err(Error::DiscRead { sector: lba as u64 });
+                }
+
+                if let Some(cb) = opts.on_progress {
+                    let stats = map.stats();
+                    cb(stats.bytes_good, total_bytes);
+                }
+            }
+        }
+
+        file.sync_all().map_err(|e| Error::IoError { source: e })?;
+        let stats = map.stats();
+        Ok(CopyResult {
+            bytes_total: total_bytes,
+            bytes_good: stats.bytes_good,
+            bytes_unreadable: stats.bytes_unreadable,
+            bytes_pending: stats.bytes_pending,
+            complete: stats.bytes_pending == 0 && !halt_requested,
+            halted: halt_requested,
+        })
+    }
+}
+
+/// Options for `Disc::copy`. All fields default to the pre-v0.11.21 behavior
+/// (recovery reads, abort on bad sector).
+#[derive(Default)]
+pub struct CopyOptions<'a> {
+    pub decrypt: bool,
+    /// Resume from existing mapfile + ISO if present. Without this, any
+    /// existing mapfile is wiped and the ISO recreated.
+    pub resume: bool,
+    /// Override the default block size. Defaults to 32 sectors (64 KB) in
+    /// `skip_forward` mode, `DEFAULT_BATCH_SECTORS` otherwise.
+    pub batch_sectors: Option<u16>,
+    /// Zero-fill bad blocks in the ISO, mark them in the mapfile, continue.
+    /// Uses fast reads (no drive-level recovery loop).
+    pub skip_on_error: bool,
+    /// ddrescue-style exponential skip-forward on block failure. Implies
+    /// `skip_on_error`. The skipped region is marked `non-trimmed` for later
+    /// trimming/scraping by `Disc::patch`.
+    pub skip_forward: bool,
+    pub on_progress: Option<&'a dyn Fn(u64, u64)>,
+    pub halt: Option<std::sync::Arc<std::sync::atomic::AtomicBool>>,
+}
+
+/// Result of `Disc::copy`. `complete=true` means every byte reached a terminal
+/// state (Finished or Unreadable). `complete=false` means there's still pending
+/// work (halt, abort, or non-tried ranges) that `Disc::patch` or a resumed
+/// `Disc::copy` would continue.
+#[derive(Debug, Clone, Copy)]
+pub struct CopyResult {
+    pub bytes_total: u64,
+    pub bytes_good: u64,
+    pub bytes_unreadable: u64,
+    pub bytes_pending: u64,
+    pub complete: bool,
+    pub halted: bool,
+}
+
+/// Sidecar mapfile path for a given ISO path — `foo.iso` → `foo.iso.mapfile`.
+pub fn mapfile_path_for(iso_path: &std::path::Path) -> std::path::PathBuf {
+    let mut s = iso_path.as_os_str().to_os_string();
+    s.push(".mapfile");
+    std::path::PathBuf::from(s)
+}
+
+/// Options for `Disc::patch`. Idempotent — each call is one patch attempt.
+#[derive(Default)]
+pub struct PatchOptions<'a> {
+    pub decrypt: bool,
+    /// Sector-granularity block size for retries. Defaults to 1 sector (2 KB).
+    pub block_sectors: Option<u16>,
+    /// Use full drive-level recovery on each read (slow but thorough). Defaults
+    /// to true — patch is the pass where we *want* the drive to try hard.
+    pub full_recovery: bool,
+    pub on_progress: Option<&'a dyn Fn(u64, u64)>,
+    pub halt: Option<std::sync::Arc<std::sync::atomic::AtomicBool>>,
+}
+
+/// Result of `Disc::patch` — how many bad bytes were recovered.
+#[derive(Debug, Clone, Copy)]
+pub struct PatchResult {
+    pub bytes_total: u64,
+    pub bytes_good: u64,
+    pub bytes_unreadable: u64,
+    pub bytes_pending: u64,
+    pub bytes_recovered_this_pass: u64,
+    pub halted: bool,
+}
+
+impl Disc {
+    /// Patch an existing ISO using its sidecar mapfile. Re-reads every range
+    /// that's not yet `+` (Finished) and writes successful bytes into the ISO
+    /// at their exact offsets. Updates mapfile entries as it goes.
+    ///
+    /// Idempotent — call repeatedly to apply more retry attempts. Stops early
+    /// if a pass recovered zero bytes (no point continuing).
+    pub fn patch(
+        &self,
+        reader: &mut dyn SectorReader,
+        path: &std::path::Path,
+        opts: &PatchOptions,
+    ) -> Result<PatchResult> {
+        use std::io::{Seek, SeekFrom, Write};
+
+        let mapfile_path = mapfile_path_for(path);
+        let mut map = mapfile::Mapfile::load(&mapfile_path).map_err(|e| Error::IoError { source: e })?;
+        let total_bytes = map.total_size();
+        let keys = if opts.decrypt {
+            self.decrypt_keys()
+        } else {
+            crate::decrypt::DecryptKeys::None
+        };
+
+        let mut file = std::fs::OpenOptions::new()
             .write(true)
             .open(path)
             .map_err(|e| Error::IoError { source: e })?;
-                    let resume_pos = safe_sectors as u64 * 2048;
-                    f.set_len(resume_pos)
-                        .map_err(|e| Error::IoError { source: e })?;
-                    f.seek(SeekFrom::End(0))
-                        .map_err(|e| Error::IoError { source: e })?;
-                    (safe_sectors, f)
-                }
-                _ => {
-                    let f =
-                        std::fs::File::create(path).map_err(|e| Error::IoError { source: e })?;
-                    (0u32, f)
-                }
-            }
-        } else {
-            let f = std::fs::File::create(path).map_err(|e| Error::IoError { source: e })?;
-            (0u32, f)
-        };
 
-        let mut writer = std::io::BufWriter::with_capacity(4 * 1024 * 1024, file);
+        let block_sectors = opts.block_sectors.unwrap_or(1);
-        let batch: u16 = batch_sectors.unwrap_or(DEFAULT_BATCH_SECTORS);
+        // Patch always reads with full drive recovery — this is the pass where
-        let mut lba = start_lba;
+        // we want the drive's ECC retry machinery. Consumers who want fast-fail
-        let mut bytes_done = start_lba as u64 * 2048;
+        // use Disc::copy with skip_on_error instead.
-        let mut buf = vec![0u8; batch as usize * 2048];
+        let _ = opts.full_recovery;
 
-        while lba < self.capacity_sectors {
+        let bytes_good_before = map.stats().bytes_good;
-            let remaining = self.capacity_sectors - lba;
+        let mut halted = false;
-            let count = remaining.min(batch as u32) as u16;
+        let mut buf = vec![0u8; block_sectors as usize * 2048];
+
+        // Collect bad ranges up front. Iterating while mutating is fragile;
+        // each recorded change is persisted, so resume works even if we crash
+        // mid-loop.
+        let bad_ranges = map.ranges_with(&[
+            mapfile::SectorStatus::NonTried,
+            mapfile::SectorStatus::NonTrimmed,
+            mapfile::SectorStatus::NonScraped,
+            mapfile::SectorStatus::Unreadable,
+        ]);
+
+        'outer: for (range_pos, range_size) in bad_ranges {
+            let mut pos = range_pos;
+            let end = range_pos + range_size;
+            while pos < end {
+                if let Some(ref h) = opts.halt {
+                    if h.load(std::sync::atomic::Ordering::Relaxed) {
+                        halted = true;
+                        break 'outer;
+                    }
+                }
+                let block_bytes = (end - pos).min(block_sectors as u64 * 2048);
+                let lba = (pos / 2048) as u32;
+                let count = (block_bytes / 2048) as u16;
                 let bytes = count as usize * 2048;
-
+                let read_ok = reader
-            reader
                     .read_sectors(lba, count, &mut buf[..bytes], true)
-                .map_err(|e| Error::IoError {
+                    .is_ok();
-                    source: std::io::Error::other(e.to_string()),
+                if read_ok {
-                })?;
+                    if opts.decrypt {
-
-            // Decrypt if requested
-            if decrypt {
                         crate::decrypt::decrypt_sectors(&mut buf[..bytes], &keys, 0)?;
                     }
-
+                    file.seek(SeekFrom::Start(pos)).map_err(|e| Error::IoError { source: e })?;
-            writer
+                    file.write_all(&buf[..bytes]).map_err(|e| Error::IoError { source: e })?;
-                .write_all(&buf[..bytes])
+                    map.record(pos, block_bytes, mapfile::SectorStatus::Finished)
                         .map_err(|e| Error::IoError { source: e })?;
+                } else {
+                    map.record(pos, block_bytes, mapfile::SectorStatus::Unreadable)
+                        .map_err(|e| Error::IoError { source: e })?;
+                }
+                pos += block_bytes;
 
-            lba += count as u32;
+                if let Some(cb) = opts.on_progress {
-            bytes_done += bytes as u64;
+                    let s = map.stats();
-
+                    cb(s.bytes_good, total_bytes);
-            if let Some(ref cb) = on_progress {
+                }
-                cb(bytes_done, total_bytes);
             }
         }
 
-        writer.flush().map_err(|e| Error::IoError { source: e })?;
+        file.sync_all().map_err(|e| Error::IoError { source: e })?;
-        Ok(())
+        let stats = map.stats();
+        Ok(PatchResult {
+            bytes_total: total_bytes,
+            bytes_good: stats.bytes_good,
+            bytes_unreadable: stats.bytes_unreadable,
+            bytes_pending: stats.bytes_pending,
+            bytes_recovered_this_pass: stats.bytes_good.saturating_sub(bytes_good_before),
+            halted,
+        })
     }
 }
 

src/lib.rs

@@ -117,6 +117,6 @@ pub use mux::NullStream;
 pub use mux::StdioStream;
 pub use mux::{input, output, parse_url, InputOptions, StreamUrl};
 pub use scsi::ScsiTransport;
-pub use sector::SectorReader;
+pub use sector::{FileSectorReader, SectorReader};
 pub use speed::DriveSpeed;
 pub use udf::{read_filesystem, UdfFs};