Add disc format parsers: UDF, MPLS, CLPI

- udf.rs: read files from Blu-ray disc filesystem
- mpls.rs: parse playlists → titles with clips and timestamps
- clpi.rs: parse clip info → EP map with coarse/fine SPN entries
- disc.rs: high-level title scanning, sector extent mapping
- drive.rs: add read_disc() for unencrypted reads, scsi_execute()
- error.rs: add E6000 DiscError

Stage 1 of freemkv rip: identify titles and their sector ranges.

src/mpls.rs

@@ -0,0 +1,123 @@
+//! MPLS playlist parser — Blu-ray movie playlists.
+//!
+//! Each .mpls file in BDMV/PLAYLIST/ defines a title.
+//! Contains play items (clips) with in/out timestamps,
+//! stream info (video, audio, subtitle tracks).
+//!
+//! Reference: https://github.com/lw/BluRay/wiki/MPLS
+
+use crate::error::{Error, Result};
+
+/// Parsed MPLS playlist.
+#[derive(Debug)]
+pub struct Playlist {
+    /// MPLS version (e.g. "0200" or "0300")
+    pub version: String,
+    /// Play items in playback order
+    pub play_items: Vec<PlayItem>,
+    /// Number of video streams
+    pub video_stream_count: u16,
+    /// Number of audio streams
+    pub audio_stream_count: u16,
+}
+
+/// A play item — one clip reference with in/out times.
+#[derive(Debug)]
+pub struct PlayItem {
+    /// Clip filename without extension (e.g. "00001")
+    pub clip_id: String,
+    /// In-time in 45kHz ticks
+    pub in_time: u32,
+    /// Out-time in 45kHz ticks
+    pub out_time: u32,
+    /// Connection condition (1=seamless, 5/6=non-seamless)
+    pub connection_condition: u8,
+}
+
+/// Parse an MPLS file from raw bytes.
+pub fn parse(data: &[u8]) -> Result<Playlist> {
+    if data.len() < 40 {
+        return Err(Error::DiscError { detail: "MPLS too short".into() });
+    }
+
+    // Header: "MPLS" + version (4 bytes ASCII)
+    if &data[0..4] != b"MPLS" {
+        return Err(Error::DiscError { detail: "not an MPLS file".into() });
+    }
+    let version = String::from_utf8_lossy(&data[4..8]).to_string();
+
+    // Offsets table at bytes 8-19
+    let playlist_start = u32::from_be_bytes([data[8], data[9], data[10], data[11]]) as usize;
+    let _playlist_mark_start = u32::from_be_bytes([data[12], data[13], data[14], data[15]]) as usize;
+
+    if playlist_start + 10 > data.len() {
+        return Err(Error::DiscError { detail: "MPLS playlist offset out of range".into() });
+    }
+
+    // PlayList section
+    let pl = &data[playlist_start..];
+    let _pl_length = u32::from_be_bytes([pl[0], pl[1], pl[2], pl[3]]) as usize;
+    // pl[4..6] reserved
+    let num_play_items = u16::from_be_bytes([pl[6], pl[7]]) as usize;
+    let _num_sub_paths = u16::from_be_bytes([pl[8], pl[9]]) as usize;
+
+    let mut play_items = Vec::with_capacity(num_play_items);
+    let mut pos = 10; // start of first play item
+
+    let mut video_streams: u16 = 0;
+    let mut audio_streams: u16 = 0;
+
+    for _ in 0..num_play_items {
+        if playlist_start + pos + 2 > data.len() {
+            break;
+        }
+
+        let item_length = u16::from_be_bytes([pl[pos], pl[pos + 1]]) as usize;
+        if playlist_start + pos + item_length + 2 > data.len() {
+            break;
+        }
+
+        let item = &pl[pos + 2..pos + 2 + item_length];
+
+        // Clip ID: 5 bytes ASCII at offset 0 (e.g. "00001")
+        let clip_id = String::from_utf8_lossy(&item[0..5]).to_string();
+        // item[5..9] = codec ID ("M2TS")
+        // item[9] = connection condition (bits)
+        let connection_condition = item[9] & 0x0F;
+        // item[10] = ref to STC_id
+        // item[12..16] = IN_time
+        let in_time = u32::from_be_bytes([item[12], item[13], item[14], item[15]]);
+        // item[16..20] = OUT_time
+        let out_time = u32::from_be_bytes([item[16], item[17], item[18], item[19]]);
+
+        // STN table follows at offset 20 within the play item
+        if item.len() > 22 {
+            let stn_length = u16::from_be_bytes([item[20], item[21]]) as usize;
+            if stn_length > 4 && item.len() > 24 {
+                // Number of primary video/audio entries
+                let n_video = item[24] as u16;
+                let n_audio = item[25] as u16;
+                if video_streams == 0 {
+                    video_streams = n_video;
+                    audio_streams = n_audio;
+                }
+            }
+        }
+
+        play_items.push(PlayItem {
+            clip_id,
+            in_time,
+            out_time,
+            connection_condition,
+        });
+
+        pos += 2 + item_length;
+    }
+
+    Ok(Playlist {
+        version,
+        play_items,
+        video_stream_count: video_streams,
+        audio_stream_count: audio_streams,
+    })
+}