Sylpheed/crates/sylpheed-formats/examples/voice_region_cap_sweep.rs

//! Is raising the start filter's 1.5 MB cap safe, disc-wide?
//!
//! `voice_region_fix_test.rs` shows that for `ADV` the predecessor start recovers
//! the decoder's own three byte_sizes exactly. But the cap exists to protect a
//! case: the code says *"only within one bank (~1.5 MB), else this is the first cue
//! in its block and the audio starts at the anchor itself"*. Raising it blindly
//! could pull a **previous asset's** streams into the region.
//!
//! So compare, per movie: the chunk list the resolver gives today against the one
//! the predecessor start gives. A safe change makes the FIRST chunk bigger and
//! leaves the rest identical. An unsafe one adds leading chunks.
//!
//!     cargo run -p sylpheed-formats --example voice_region_cap_sweep

use sylpheed_formats::hash::name_hash;
use sylpheed_formats::media::{DirectorySource, DiscSource};
use sylpheed_formats::pak::PakArchive;
use sylpheed_formats::slb::{self, VoiceLang};
use sylpheed_formats::{movie_manifest, movie_voice};

fn main() {
    let disc = std::env::var("SYLPHEED_DISC").expect("SYLPHEED_DISC");
    let src = DirectorySource::new(std::path::PathBuf::from(&disc));
    let code = VoiceLang::English.code_pub();
    let tpak = src.open_pak("dat/tables.pak").expect("tables.pak");
    let manifest = tpak.entries().iter()
        .find_map(|e| tpak.read(e).ok().filter(|b| movie_manifest::is_manifest(b)))
        .expect("manifest");
    let marker = format!("{code}\\Movie\\VOICE_ADV.slb");
    let registry = tpak.entries().iter().find_map(|e| {
        tpak.read(e).ok().filter(|b| b.windows(marker.len()).any(|w| w == marker.as_bytes()))
    }).expect("registry");
    let ids = movie_voice::registry_voice_ids(&registry);
    let stoc = src.read_file("dat/sound.pak").expect("sound.pak");
    let entries = PakArchive::parse_toc(&stoc).expect("toc");

    let (mut same, mut grew, mut extra, mut skip) = (0, 0, 0, 0);
    for m in movie_manifest::parse(&manifest) {
        let movie = m.movie;
        let Some(token) = movie_manifest::voice_token(&manifest, &movie) else { skip += 1; continue };
        let Some(&id) = ids.get(&token) else { skip += 1; continue };
        let Some(anchor) = ["Movie","etc","Voice"].iter().find_map(|dir| {
            let h = name_hash(&format!("{code}\\{dir}\\{token}.slb"));
            entries.binary_search_by_key(&h, |e| e.name_hash).ok().map(|i| entries[i].offset as u64)
        }) else { skip += 1; continue };
        let win_start = anchor.saturating_sub(2*1024*1024) & !3;
        let Ok(window) = src.read_segment_range("dat/sound", win_start, 8*1024*1024) else { skip += 1; continue };
        let Some(end_local) = movie_voice::find_descriptor(&window, id) else { skip += 1; continue };
        let end = win_start + end_local as u64;
        let cand = movie_voice::find_descriptor(&window, id.wrapping_sub(1))
            .or_else(|| movie_voice::find_descriptor_before(&window, end_local))
            .map(|o| win_start + o as u64)
            .filter(|&s| s < end);
        let today = cand.filter(|&s| end - s < 1_500_000).unwrap_or(anchor);
        let Some(proposed) = cand else { skip += 1; continue };
        if today == proposed { same += 1; continue }
        let sizes = |s: u64| -> Vec<usize> {
            src.read_segment_range("dat/sound", s, (end - s) as usize)
                .map(|b| slb::to_xma_riffs(&b).iter().map(|r| r.len() - 60).collect())
                .unwrap_or_default()
        };
        let (a, b) = (sizes(today), sizes(proposed));
        let tail_same = a.len() == b.len() && a.iter().skip(1).eq(b.iter().skip(1));
        let verdict = if a.len() == b.len() && tail_same && b[0] > a[0] {
            grew += 1; "first chunk GREW, tail identical"
        } else if b.len() > a.len() { extra += 1; "EXTRA leading chunks" }
        else { extra += 1; "changed otherwise" };
        println!("{movie:10} today {a:?}\n{:10} prop  {b:?}   {verdict}", "");
    }
    println!("\nunchanged {same}   fixed-cleanly {grew}   would-break {extra}   skipped {skip}");
}