xmrs 0.14.6

//! `Module::load_*` impls — auto-detect a tracker file's format
//! from its header and dispatch to the matching format-specific
//! loader (`load_mod`, `load_xm`, `load_s3m`, `load_it`, `load_dw`).
//! SID files are loaded via `SidModule::load` directly and don't go
//! through the autodetect path. DW *is* auto-detected even without
//! a magic header — its probe quadruple is unique enough.

use crate::prelude::*;
use crate::tracker::import::bin_reader::ImportError;

// The module-level gate in `crate::tracker::import::mod` only compiles
// this file when at least one of MOD/XM/S3M/IT/DW is enabled, so
// `load` below always has at least one live branch and `source` is
// always used.

impl Module {
    /// Try to import an Amiga ProTracker MOD file.
    #[cfg(feature = "import_mod")]
    pub fn load_mod(source: &[u8]) -> Result<Self, ImportError> {
        use super::amiga::amiga_module::AmigaModule;

        Ok(AmigaModule::load(source)?.to_module())
    }

    /// Try to import a Fast Tracker II XM module file.
    #[cfg(feature = "import_xm")]
    pub fn load_xm(source: &[u8]) -> Result<Self, ImportError> {
        use super::xm::xmmodule::XmModule;

        Ok(XmModule::load(source)?.to_module())
    }

    /// Try to import a ScreamTracker 3 S3M module file.
    #[cfg(feature = "import_s3m")]
    pub fn load_s3m(source: &[u8]) -> Result<Self, ImportError> {
        use super::s3m::s3m_module::S3mModule;

        Ok(S3mModule::load(source)?.to_module())
    }

    /// Try to import an Impulse Tracker IT module file.
    #[cfg(feature = "import_it")]
    pub fn load_it(source: &[u8]) -> Result<Self, ImportError> {
        use super::it::it_module::ItModule;

        Ok(ItModule::load(source)?.to_module())
    }

    /// Try to import a David Whittaker custom Amiga `.dw` file.
    /// The detection layer runs a probe-quadruple scan (`LEA /
    /// LEA / MOVEQ / DBF`) over the first ~4 KB of the payload
    /// and walks the BSR call graph from there; no magic header
    /// is required.
    #[cfg(feature = "import_dw")]
    pub fn load_dw(source: &[u8]) -> Result<Self, ImportError> {
        use super::dw::dw_module::DwModule;

        Ok(DwModule::load(source)?.to_module())
    }

    /// Import a `.dw` from bytes and give it an explicit title.
    ///
    /// The `.dw` format carries no textual title — the byte-only
    /// [`Self::load_dw`] therefore tags every module with the same
    /// `"David Whittaker (.dw)"` placeholder, which is useless once
    /// several songs sit side by side in an editor. This variant runs
    /// the exact same importer, then overrides [`Module::name`] with
    /// `name` (an empty `name` is ignored, keeping the placeholder).
    ///
    /// Titling needs only `alloc`, so this works in `no_std` builds:
    /// a caller that already has the bytes and a name (from any
    /// source) can title the module without pulling in `std`. The
    /// std-only [`Self::load_dw_path`] is a thin convenience over this.
    #[cfg(feature = "import_dw")]
    pub fn load_dw_named(source: &[u8], name: &str) -> Result<Self, ImportError> {
        let mut module = Self::load_dw(source)?;
        if !name.is_empty() {
            module.name = name.into();
        }
        Ok(module)
    }

    /// Import a `.dw` file from disk and title it after the file name.
    ///
    /// Reads `path`, then delegates to [`Self::load_dw_named`] with the
    /// file stem (the name minus its extension, e.g. `xenon2.dw` →
    /// `xenon2`). Requires `std` for the filesystem read; the titling
    /// itself does not — see [`Self::load_dw_named`].
    #[cfg(all(feature = "import_dw", feature = "std"))]
    pub fn load_dw_path<P: AsRef<std::path::Path>>(path: P) -> Result<Self, ImportError> {
        let path = path.as_ref();
        let data = std::fs::read(path).map_err(|_| ImportError::Other("dw: cannot read file"))?;
        let stem = path.file_stem().and_then(|s| s.to_str()).unwrap_or("");
        Self::load_dw_named(&data, stem)
    }

    /// Try to auto-detect and import any supported historical module
    /// file (MOD / XM / S3M / IT / DW). Formats are tried in the
    /// order XM → S3M → IT → MOD → DW. The Amiga MOD format is
    /// tried late because its detection accepts almost anything;
    /// DW comes after MOD because its detection is structural
    /// (no magic header at all) — running it last avoids ever
    /// stealing a valid MOD parse. Only formats whose `import_*`
    /// feature is enabled are attempted.
    ///
    /// SID is not auto-detected here — it has its own dedicated entry
    /// point via `crate::tracker::import::sid::sid_module::SidModule::load`.
    pub fn load(source: &[u8]) -> Result<Self, ImportError> {
        #[cfg(feature = "import_xm")]
        if let Ok(m) = Self::load_xm(source) {
            return Ok(m);
        };

        #[cfg(feature = "import_s3m")]
        if let Ok(m) = Self::load_s3m(source) {
            return Ok(m);
        };

        #[cfg(feature = "import_it")]
        if let Ok(m) = Self::load_it(source) {
            return Ok(m);
        };

        // The amiga format is tried late because it accepts almost
        // anything as a 15-sample Soundtracker variant.
        #[cfg(feature = "import_mod")]
        if let Ok(m) = Self::load_mod(source) {
            return Ok(m);
        };

        // DW has no header magic at all — its detector scans for
        // an opcode quadruple in the first few KB. Running it
        // last keeps it from intercepting a MOD that happens to
        // begin with the right bytes.
        #[cfg(feature = "import_dw")]
        if let Ok(m) = Self::load_dw(source) {
            return Ok(m);
        };

        // When no MOD/XM/S3M/IT/DW feature is enabled the whole
        // `import_loader` module is gated out in `import::mod`, so
        // we never reach this arm with `source` being the only live
        // binding — the compiler always sees at least one of the
        // `#[cfg]` blocks above as active. The `let _ = source;` is
        // a belt-and-braces silencer for the rare case where only
        // one `load_*` is compiled and a stubborn linter still
        // complains.
        let _ = source;

        Err(ImportError::Other("Unknown data?"))
    }
}