epics_base_rs/types/

dbr.rs

use crate::error::{CaError, CaResult};

// DBR type ranges (matches db_access.h):
//   native (0..=6), STS (7..=13), TIME (14..=20), GR (21..=27),
//   CTRL (28..=34), special PUT_ACKT (35), PUT_ACKS (36),
//   STSACK_STRING (37), CLASS_NAME (38).

// Native scalar types (also exposed via DbFieldType enum)
pub const DBR_STRING: u16 = 0;
pub const DBR_SHORT: u16 = 1;
pub const DBR_FLOAT: u16 = 2;
pub const DBR_ENUM: u16 = 3;
pub const DBR_CHAR: u16 = 4;
pub const DBR_LONG: u16 = 5;
pub const DBR_DOUBLE: u16 = 6;
// `DBR_INT` is the libca alias for `DBR_SHORT`.
pub const DBR_INT: u16 = DBR_SHORT;

// Status-only metadata layer (CA-261)
pub const DBR_STS_STRING: u16 = 7;
pub const DBR_STS_SHORT: u16 = 8;
pub const DBR_STS_FLOAT: u16 = 9;
pub const DBR_STS_ENUM: u16 = 10;
pub const DBR_STS_CHAR: u16 = 11;
pub const DBR_STS_LONG: u16 = 12;
pub const DBR_STS_DOUBLE: u16 = 13;
pub const DBR_STS_INT: u16 = DBR_STS_SHORT;

// Status + timestamp layer (CA-262)
pub const DBR_TIME_STRING: u16 = 14;
pub const DBR_TIME_SHORT: u16 = 15;
pub const DBR_TIME_FLOAT: u16 = 16;
pub const DBR_TIME_ENUM: u16 = 17;
pub const DBR_TIME_CHAR: u16 = 18;
pub const DBR_TIME_LONG: u16 = 19;
pub const DBR_TIME_DOUBLE: u16 = 20;
pub const DBR_TIME_INT: u16 = DBR_TIME_SHORT;

// Status + graphic (display limits / units / precision) layer (CA-263)
pub const DBR_GR_STRING: u16 = 21;
pub const DBR_GR_SHORT: u16 = 22;
pub const DBR_GR_FLOAT: u16 = 23;
pub const DBR_GR_ENUM: u16 = 24;
pub const DBR_GR_CHAR: u16 = 25;
pub const DBR_GR_LONG: u16 = 26;
pub const DBR_GR_DOUBLE: u16 = 27;
pub const DBR_GR_INT: u16 = DBR_GR_SHORT;

// Status + graphic + control limits layer (CA-264)
pub const DBR_CTRL_STRING: u16 = 28;
pub const DBR_CTRL_SHORT: u16 = 29;
pub const DBR_CTRL_FLOAT: u16 = 30;
pub const DBR_CTRL_ENUM: u16 = 31;
pub const DBR_CTRL_CHAR: u16 = 32;
pub const DBR_CTRL_LONG: u16 = 33;
pub const DBR_CTRL_DOUBLE: u16 = 34;
pub const DBR_CTRL_INT: u16 = DBR_CTRL_SHORT;

// Special alarm-acknowledgement / introspection types
pub const DBR_PUT_ACKT: u16 = 35;
pub const DBR_PUT_ACKS: u16 = 36;
pub const DBR_STSACK_STRING: u16 = 37;
/// Returns the IOC's record-type class name as a 40-byte string
/// (CA-268, db_access.h: `DBR_CLASS_NAME`).
pub const DBR_CLASS_NAME: u16 = 38;

/// Last allocated DBR type code, matching the C `LAST_BUFFER_TYPE` macro.
pub const LAST_BUFFER_TYPE: u16 = DBR_CLASS_NAME;

/// EPICS DBR field types (native types only)
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
#[repr(u16)]
pub enum DbFieldType {
    String = 0,
    Short = 1, // aka Int16
    Float = 2,
    Enum = 3,
    Char = 4, // aka UInt8
    Long = 5, // aka Int32
    Double = 6,
    /// Internal-only type for int64in/int64out records.
    /// No CA wire type 7 exists; over CA these PVs appear as Double (type 6).
    Int64 = 7,
    /// Internal-only type for unsigned 64-bit EPICS fields (C `DBF_UINT64`,
    /// dbStatic `dbfType` index 8). The CA wire protocol has no 64-bit
    /// type, so over CA these PVs appear as Double (type 6); over PVA they
    /// are served natively as `ulong`. Mirrors `Int64`'s CA handling.
    UInt64 = 8,
    /// Internal-only type for unsigned 16-bit EPICS fields (C `DBF_USHORT`,
    /// dbStatic `dbfType`). The CA wire protocol has no unsigned types, so
    /// the IOC promotes `DBF_USHORT` to the next signed type that holds its
    /// full `0..=65535` range — `DBR_LONG` (the C `dbDBRnewToDBRold` table,
    /// `db_convert.h`: `5, /*DBR_USHORT to DBR_LONG*/`). Over PVA pvxs
    /// serves it natively as `ushort` (`ioc/typeutils.cpp:38-40`:
    /// `DBR_USHORT -> TypeCode::UInt16`). The discriminant is an internal
    /// marker (not a CA wire code); see [`Self::ca_wire_type`].
    UShort = 9,
    /// Internal-only type for unsigned 32-bit EPICS fields (C `DBF_ULONG`,
    /// dbStatic `dbfType`). `0..=4294967295` does not fit in `i32`, so the
    /// IOC promotes `DBF_ULONG` to `DBR_DOUBLE` over CA exactly like
    /// `UInt64`/`Int64` (`db_convert.h`: `6, /*DBR_ULONG to DBR_DOUBLE*/`).
    /// Over PVA pvxs serves it natively as `uint` (`ioc/typeutils.cpp:43-44`:
    /// `DBR_ULONG -> TypeCode::UInt32`).
    ULong = 10,
    /// Internal-only type for unsigned 8-bit EPICS fields (C `DBF_UCHAR`,
    /// dbStatic `dbfType` index 2 / `waveform` `FTVL=UCHAR`). Unlike the
    /// signed `Char` (epicsInt8), this is epicsUInt8. The CA wire protocol
    /// has no unsigned types, so the IOC promotes `DBF_UCHAR` to `DBR_CHAR`
    /// — the same 1-byte wire type as `Char` (the C `dbDBRnewToDBRold` table,
    /// `db_convert.h`: `4, /*DBR_UCHAR to DBR_CHAR*/`); the raw bytes are
    /// identical, only the signedness of the interpretation differs. Over PVA
    /// pvxs serves it natively as `ubyte` (`ioc/typeutils.cpp:34-35`:
    /// `DBR_UCHAR -> TypeCode::UInt8`), distinct from `Char`'s signed `byte`.
    /// The discriminant is an internal marker (not a CA wire code); see
    /// [`Self::ca_wire_type`].
    UChar = 11,
}

impl DbFieldType {
    pub fn from_u16(v: u16) -> CaResult<Self> {
        match v {
            0 => Ok(Self::String),
            1 => Ok(Self::Short),
            2 => Ok(Self::Float),
            3 => Ok(Self::Enum),
            4 => Ok(Self::Char),
            5 => Ok(Self::Long),
            6 => Ok(Self::Double),
            _ => Err(CaError::UnsupportedType(v)),
        }
    }

    /// Size in bytes for a single element of this type's native carrier.
    ///
    /// This is the carrier width (`UShort` = 2, `ULong` = 4), not the
    /// CA-wire-promoted width: the CA value path always promotes via
    /// [`crate::types::EpicsValue::dbr_type`] first and sizes buffers off
    /// the promoted type (`UShort`→`Long`=4, `ULong`→`Double`=8), so this
    /// width is never used to size a CA value array for the unsigned types.
    pub fn element_size(&self) -> usize {
        match self {
            Self::String => 40, // MAX_STRING_SIZE
            Self::Short | Self::Enum | Self::UShort => 2,
            Self::Float | Self::Long | Self::ULong => 4,
            Self::Char | Self::UChar => 1,
            Self::Double | Self::Int64 | Self::UInt64 => 8,
        }
    }

    /// Return the wire type code as a `u16`. The internal-only types have
    /// no CA wire code, so they report the signed CA type the IOC promotes
    /// them to (C `dbDBRnewToDBRold`, `db_convert.h`): `Int64`/`UInt64`/
    /// `ULong` → `DBR_DOUBLE` (6), `UShort` → `DBR_LONG` (5, the smallest
    /// signed CA type that holds the full `0..=65535` range), `UChar` →
    /// `DBR_CHAR` (4, same 1-byte wire type — the bytes are identical, only
    /// the interpretation is unsigned).
    fn ca_wire_type(&self) -> u16 {
        match self {
            Self::Int64 | Self::UInt64 | Self::ULong => Self::Double as u16,
            Self::UShort => Self::Long as u16,
            Self::UChar => Self::Char as u16,
            other => *other as u16,
        }
    }

    /// Return the `DBR_STS_xxx` type code for this native type
    /// (Int64 maps to `DBR_STS_DOUBLE`).
    pub fn sts_dbr_type(&self) -> u16 {
        self.ca_wire_type() + 7
    }

    /// Return the `DBR_TIME_xxx` type code for this native type
    /// (Int64 maps to `DBR_TIME_DOUBLE`).
    pub fn time_dbr_type(&self) -> u16 {
        self.ca_wire_type() + 14
    }

    /// Return the `DBR_GR_xxx` type code for this native type
    /// (Int64 maps to `DBR_GR_DOUBLE`).
    pub fn gr_dbr_type(&self) -> u16 {
        self.ca_wire_type() + 21
    }

    /// Return the `DBR_CTRL_xxx` type code for this native type
    /// (Int64 maps to `DBR_CTRL_DOUBLE`).
    pub fn ctrl_dbr_type(&self) -> u16 {
        self.ca_wire_type() + 28
    }

    /// Calculate total buffer size for N elements of this type.
    /// Equivalent to C EPICS dbValueSize(type) * count.
    pub fn buffer_size(&self, count: usize) -> usize {
        self.element_size() * count
    }

    /// Map field type to request type (C EPICS mapDBFToDBR).
    /// DBF_MENU and DBF_DEVICE map to DBR_ENUM in C EPICS.
    /// In Rust these are already represented as DbFieldType::Enum,
    /// so this is an identity mapping for documentation/completeness.
    pub fn to_dbr_type(&self) -> DbFieldType {
        *self
    }
}

/// dbStatic link-field classes — the three `dbfType` values that mark a
/// record field as a *link* rather than a value
/// (`dbFldTypes.h`: `DBF_INLINK`=14, `DBF_OUTLINK`=15, `DBF_FWDLINK`=16).
///
/// pvxs rejects a QSRV group PUT to any field whose
/// `dbChannelFinalFieldType` falls in `DBF_INLINK..=DBF_FWDLINK`
/// (`ioc/groupsource.cpp:596-606`). The Rust port has no dbStatic field
/// table, so [`dbf_link_class`] reconstructs the same classification from
/// the EPICS Base / synApps `*.dbd(.pod)` link-field families and returns
/// the matching class. Consumers gate "is this field a link" on
/// `dbf_link_class(..).is_some()` (or [`is_link_dbf_type`] when they
/// already hold a dbStatic code), rather than maintaining their own
/// partial spelling lists.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
#[repr(u8)]
pub enum DbfLinkClass {
    /// `DBF_INLINK` (14) — an input link (`INP`, `DOL`, `SIML`, …).
    InLink = DBF_INLINK,
    /// `DBF_OUTLINK` (15) — an output link (`OUT`, `LNKn`, …).
    OutLink = DBF_OUTLINK,
    /// `DBF_FWDLINK` (16) — a forward link (`FLNK`).
    FwdLink = DBF_FWDLINK,
}

/// `dbFldTypes.h` `DBF_INLINK`.
pub const DBF_INLINK: u8 = 14;
/// `dbFldTypes.h` `DBF_OUTLINK`.
pub const DBF_OUTLINK: u8 = 15;
/// `dbFldTypes.h` `DBF_FWDLINK`.
pub const DBF_FWDLINK: u8 = 16;

impl DbfLinkClass {
    /// The dbStatic `dbfType` numeric code (`dbFldTypes.h`).
    pub fn dbf_type(self) -> u8 {
        self as u8
    }
}

/// True iff `dbf_type` is a link class — the exact
/// `DBF_INLINK <= t <= DBF_FWDLINK` range check pvxs applies in
/// `ioc/groupsource.cpp:596-606`. Use when a caller already holds a
/// dbStatic field-type code; [`dbf_link_class`] is the name-keyed entry
/// point for the Rust port, which carries no dbStatic table.
pub fn is_link_dbf_type(dbf_type: u8) -> bool {
    (DBF_INLINK..=DBF_FWDLINK).contains(&dbf_type)
}

/// Classify a record field by its dbStatic link class, or `None` when it
/// is not a link field. This is the single canonical owner of the
/// "is this field a link" rule for the Rust port — the structural
/// replacement for the partial, per-consumer name lists that the
/// `groupsource.cpp:596-606` review flagged (a record-type-blind
/// spelling list re-opens the bypass for every record that names a link
/// field outside the list).
///
/// `record_type` is the record's `recordType` (`ai`, `bo`, `seq`, …); it
/// is consulted to resolve the two direction-ambiguous fields that share a
/// spelling across record families:
///   - `SIOL` is `DBF_OUTLINK` on output records and `DBF_INLINK` on input
///     records (compare `boRecord.dbd.pod:318` `SIOL,DBF_OUTLINK` vs
///     `aiRecord`/`biRecord` `SIOL,DBF_INLINK`).
///   - `LNK0..LNKF` is `DBF_FWDLINK` on `fanoutRecord` (the multi-forward
///     fan-out family) and `DBF_OUTLINK` on `seqRecord` / synApps
///     `sseqRecord` (compare `fanoutRecord.dbd.pod` `field(LNK0,DBF_FWDLINK)`
///     vs `seqRecord.dbd.pod` `field(LNK0,DBF_OUTLINK)`).
///
/// Every other family has a fixed class across all record types.
///
/// Names and classes are taken verbatim from EPICS Base / synApps
/// `*.dbd(.pod)`:
///   - dbCommon: `FLNK`→Fwd, `SDIS`/`TSEL`→In.
///   - `INP`/`DOL`/`SIML`/`NVL`/`SVL`/`SUBL`/`SELL`→In, `OUT`→Out.
///   - `SIOL`→Out on output records, else In.
///   - `INPA..INPU`/`INP0..INP9`→In; `OUTA..OUTU`→Out.
///   - `DOL0..DOL9`/`DOLA..DOLF`→In.
///   - `LNK0..LNK9`/`LNKA..LNKF`→Fwd on `fanout`, else Out.
pub fn dbf_link_class(record_type: &str, field: &str) -> Option<DbfLinkClass> {
    use DbfLinkClass::*;
    let f = field.trim().to_ascii_uppercase();

    // Exact dbCommon + record-specific named link fields.
    match f.as_str() {
        "FLNK" => return Some(FwdLink),
        "SDIS" | "TSEL" | "INP" | "DOL" | "SIML" | "NVL" | "SVL" | "SUBL" | "SELL" => {
            return Some(InLink);
        }
        "OUT" => return Some(OutLink),
        "SIOL" => {
            return Some(if is_output_record_type(record_type) {
                OutLink
            } else {
                InLink
            });
        }
        _ => {}
    }

    // Indexed / lettered link families: a known prefix plus exactly one
    // alphanumeric suffix character. The DBDs use `A..U` / `0..9` / `A..F`,
    // but any single-alnum suffix on these prefixes is a link in every
    // base record that defines the family, so a one-char-suffix rule is
    // both complete and on the safe (reject) side for custom records.
    let one_alnum = |rest: &str| rest.len() == 1 && rest.as_bytes()[0].is_ascii_alphanumeric();
    // `LNK0..LNKF` is direction-ambiguous by record type the same way
    // `SIOL` is: `fanoutRecord` declares the family as `DBF_FWDLINK`
    // (multi-forward fan-out), every other family that uses the spelling
    // (`seqRecord`, synApps `sseqRecord`) declares it `DBF_OUTLINK`.
    // Resolve it once here so the prefix table below carries a single
    // class per spelling rather than collapsing fanout's forward links to
    // output links by prefix.
    let lnk_class = if is_fanout_link_record(record_type) {
        FwdLink
    } else {
        OutLink
    };
    for (prefix, class) in [
        ("INP", InLink),
        ("DOL", InLink),
        ("OUT", OutLink),
        ("LNK", lnk_class),
    ] {
        if let Some(rest) = f.strip_prefix(prefix) {
            if one_alnum(rest) {
                return Some(class);
            }
        }
    }
    None
}

/// Record types whose `SIOL` simulation-output link is `DBF_OUTLINK`
/// (the output records). Input records declare `SIOL` as `DBF_INLINK`.
/// Same output-record set as the device-write records — compare
/// `crate::server::record::Record::can_device_write`.
fn is_output_record_type(record_type: &str) -> bool {
    matches!(
        record_type,
        "ao" | "bo" | "longout" | "int64out" | "mbbo" | "mbboDirect" | "stringout" | "lso" | "aao"
    )
}

/// `fanoutRecord` is the one Base family whose `LNK0..LNKF` fields are
/// `DBF_FWDLINK` (forward links fired in numerical order). Every other
/// family that uses the same `LNK*` spelling — `seqRecord`, synApps
/// `sseqRecord` — declares them `DBF_OUTLINK`. Compare
/// `fanoutRecord.dbd.pod` `field(LNK0,DBF_FWDLINK)` vs `seqRecord.dbd.pod`
/// `field(LNK0,DBF_OUTLINK)`.
fn is_fanout_link_record(record_type: &str) -> bool {
    record_type == "fanout"
}

/// Calculate buffer size for a DBR type including metadata, matching C
/// `dbr_size_n(TYPE, COUNT) = dbr_size[TYPE] + (COUNT-1)*dbr_value_size[TYPE]`.
///
/// the metadata length is taken from
/// [`crate::types::codec::dbr_meta_size`] — the single owner that the
/// serializers (`serialize_dbr` / `encode_dbr`) emit against — so the
/// explicit-count pad/truncate and no-read-access frame paths size
/// TIME / GR / CTRL bodies exactly as the encoder writes them. A
/// `metadata_matches_encoded_length` test pins `encoded_len ==
/// dbr_buffer_size` across the whole (dbr_type, native) matrix, so the
/// sizer can no longer drift from the encoder.
pub fn dbr_buffer_size(dbr_type: u16, native_type: DbFieldType, count: usize) -> usize {
    // DBR_CLASS_NAME (38) is always one MAX_STRING_SIZE (40) string,
    // regardless of `count` or `native_type` — it carries no value[]
    // array, so the generic meta+value formula does not apply.
    if dbr_type == DBR_CLASS_NAME {
        return 40;
    }
    let value_size = native_type.element_size() * count;
    crate::types::codec::dbr_meta_size(dbr_type, native_type) + value_size
}

/// Extract the native DBF type index (0-6) from any DBR type code.
fn dbr_native_index(dbr_type: u16) -> Option<u16> {
    match dbr_type {
        0..=6 => Some(dbr_type),
        7..=13 => Some(dbr_type - 7),
        14..=20 => Some(dbr_type - 14),
        21..=27 => Some(dbr_type - 21),
        28..=34 => Some(dbr_type - 28),
        // Alarm-acknowledge writes carry a single u16, so map them to
        // Short for codec purposes. STSACK_STRING returns a string body
        // so it maps to String.
        35 | 36 => Some(1), // DBR_PUT_ACKT / DBR_PUT_ACKS — u16
        37 => Some(0),      // DBR_STSACK_STRING — value is a string
        // DBR_CLASS_NAME is a single fixed 40-byte string carrying the
        // record's recordType. Treat as String for codec purposes.
        38 => Some(0),
        _ => None,
    }
}

pub fn native_type_for_dbr(dbr_type: u16) -> CaResult<DbFieldType> {
    match dbr_native_index(dbr_type) {
        Some(idx) => DbFieldType::from_u16(idx),
        None => Err(CaError::UnsupportedType(dbr_type)),
    }
}

/// DBR request-type names indexed by type code, mirroring the C
/// `dbr_text[]` table (`ca/src/client/access.cpp`). Index 0 =
/// `DBR_STRING` … index 38 = `DBR_CLASS_NAME`.
const DBR_TEXT: [&str; (LAST_BUFFER_TYPE + 1) as usize] = [
    "DBR_STRING",
    "DBR_SHORT",
    "DBR_FLOAT",
    "DBR_ENUM",
    "DBR_CHAR",
    "DBR_LONG",
    "DBR_DOUBLE",
    "DBR_STS_STRING",
    "DBR_STS_SHORT",
    "DBR_STS_FLOAT",
    "DBR_STS_ENUM",
    "DBR_STS_CHAR",
    "DBR_STS_LONG",
    "DBR_STS_DOUBLE",
    "DBR_TIME_STRING",
    "DBR_TIME_SHORT",
    "DBR_TIME_FLOAT",
    "DBR_TIME_ENUM",
    "DBR_TIME_CHAR",
    "DBR_TIME_LONG",
    "DBR_TIME_DOUBLE",
    "DBR_GR_STRING",
    "DBR_GR_SHORT",
    "DBR_GR_FLOAT",
    "DBR_GR_ENUM",
    "DBR_GR_CHAR",
    "DBR_GR_LONG",
    "DBR_GR_DOUBLE",
    "DBR_CTRL_STRING",
    "DBR_CTRL_SHORT",
    "DBR_CTRL_FLOAT",
    "DBR_CTRL_ENUM",
    "DBR_CTRL_CHAR",
    "DBR_CTRL_LONG",
    "DBR_CTRL_DOUBLE",
    "DBR_PUT_ACKT",
    "DBR_PUT_ACKS",
    "DBR_STSACK_STRING",
    "DBR_CLASS_NAME",
];

/// Resolve a DBR request-type name to its type code, mirroring the C
/// `dbr_text_to_type` macro (`db_access.h`): an exact, **case-sensitive**
/// `strcmp` search of the `dbr_text[]` table. Returns the matching code
/// (`0..=38`) or `None` when no name matches.
///
/// The case sensitivity is faithful to C — the `caget`/`caput` tools
/// feed `-d <type>` straight through this search, so `-d DBR_TIME_FLOAT`
/// resolves while `-d dbr_time_float` does not (the C tool then reverts
/// to its plain/native request). Callers that accept the bare family
/// (`caget -d TIME_FLOAT`) retry with a `DBR_` prefix, exactly as
/// `caget.c` does.
pub fn dbr_text_to_type(text: &str) -> Option<u16> {
    DBR_TEXT.iter().position(|&n| n == text).map(|i| i as u16)
}

#[cfg(test)]
mod buffer_size_tests {
    use super::*;

    /// STS meta size is per-type. `dbr_sts_double` carries a
    /// 4-byte `dbr_long_t` RISC_pad (db_access.h:233-238) → meta 8.
    #[test]
    fn sts_double_meta_is_8() {
        // scalar: 8 (meta) + 8 (value) = 16
        assert_eq!(dbr_buffer_size(DBR_STS_DOUBLE, DbFieldType::Double, 1), 16);
        // n elements: 8 + 8*n
        assert_eq!(
            dbr_buffer_size(DBR_STS_DOUBLE, DbFieldType::Double, 5),
            8 + 8 * 5
        );
    }

    /// `dbr_sts_char` carries a 1-byte RISC_pad
    /// (db_access.h:218-223) → meta 5.
    #[test]
    fn sts_char_meta_is_5() {
        assert_eq!(dbr_buffer_size(DBR_STS_CHAR, DbFieldType::Char, 1), 6);
        assert_eq!(dbr_buffer_size(DBR_STS_CHAR, DbFieldType::Char, 10), 5 + 10);
    }

    /// types with no STS RISC pad keep the flat 4-byte meta.
    #[test]
    fn sts_short_meta_is_4() {
        assert_eq!(dbr_buffer_size(DBR_STS_SHORT, DbFieldType::Short, 1), 6);
        assert_eq!(dbr_buffer_size(DBR_STS_LONG, DbFieldType::Long, 1), 8);
        assert_eq!(dbr_buffer_size(DBR_STS_FLOAT, DbFieldType::Float, 1), 8);
    }

    /// Plain values carry no metadata.
    #[test]
    fn plain_value_size_only() {
        assert_eq!(dbr_buffer_size(DBR_DOUBLE, DbFieldType::Double, 3), 24);
    }

    /// TIME structs carry a per-type RISC pad before `value[0]`
    /// (C `dbr_time_*`, db_access.h:250-300). The pre-fix flat 12-byte
    /// TIME meta truncated double/short/enum/char bodies.
    #[test]
    fn time_meta_includes_risc_pad() {
        // double: 12 + RISC_pad(4) + value(8) = 24 (was wrongly 20).
        assert_eq!(dbr_buffer_size(DBR_TIME_DOUBLE, DbFieldType::Double, 1), 24);
        // short/enum: 12 + pad(2) + value(2) = 16.
        assert_eq!(dbr_buffer_size(DBR_TIME_SHORT, DbFieldType::Short, 1), 16);
        assert_eq!(dbr_buffer_size(DBR_TIME_ENUM, DbFieldType::Enum, 1), 16);
        // char: 12 + pad(3) + value(1) = 16.
        assert_eq!(dbr_buffer_size(DBR_TIME_CHAR, DbFieldType::Char, 1), 16);
        // float/long: no pad (value already 4-aligned at offset 12).
        assert_eq!(dbr_buffer_size(DBR_TIME_FLOAT, DbFieldType::Float, 1), 16);
        assert_eq!(dbr_buffer_size(DBR_TIME_LONG, DbFieldType::Long, 1), 16);
        // Explicit count scales the value array after the pad.
        assert_eq!(
            dbr_buffer_size(DBR_TIME_DOUBLE, DbFieldType::Double, 4),
            16 + 8 * 4
        );
    }

    /// GR/CTRL metadata is per native type (the pre-fix single
    /// broad formula over-padded short/char/float/long and dropped the
    /// enum `no_str` word).
    #[test]
    fn gr_ctrl_meta_is_per_type() {
        // GR (6 limits): head(4) + layout.
        assert_eq!(dbr_buffer_size(DBR_GR_SHORT, DbFieldType::Short, 1), 24 + 2);
        assert_eq!(dbr_buffer_size(DBR_GR_FLOAT, DbFieldType::Float, 1), 40 + 4);
        assert_eq!(
            dbr_buffer_size(DBR_GR_DOUBLE, DbFieldType::Double, 1),
            64 + 8
        );
        assert_eq!(dbr_buffer_size(DBR_GR_CHAR, DbFieldType::Char, 1), 19 + 1);
        assert_eq!(dbr_buffer_size(DBR_GR_LONG, DbFieldType::Long, 1), 36 + 4);
        // Enum: head(4) + no_str(2) + 16*26 strings = 422, value(2).
        assert_eq!(dbr_buffer_size(DBR_GR_ENUM, DbFieldType::Enum, 1), 422 + 2);
        // CTRL adds two control limits.
        assert_eq!(
            dbr_buffer_size(DBR_CTRL_DOUBLE, DbFieldType::Double, 1),
            80 + 8
        );
        assert_eq!(
            dbr_buffer_size(DBR_CTRL_SHORT, DbFieldType::Short, 1),
            28 + 2
        );
        assert_eq!(dbr_buffer_size(DBR_CTRL_CHAR, DbFieldType::Char, 1), 21 + 1);
    }
}

#[cfg(test)]
mod dbf_link_class_tests {
    use super::*;

    #[test]
    fn dbcommon_links_classified_uniformly() {
        // Present on every record (dbCommon.dbd).
        assert_eq!(dbf_link_class("ai", "FLNK"), Some(DbfLinkClass::FwdLink));
        assert_eq!(dbf_link_class("ao", "SDIS"), Some(DbfLinkClass::InLink));
        assert_eq!(dbf_link_class("calc", "TSEL"), Some(DbfLinkClass::InLink));
    }

    #[test]
    fn record_specific_link_families_the_old_name_list_missed() {
        // The families the reviewed partial spelling list omitted, each a
        // DBF_INLINK/OUTLINK in EPICS Base `*.dbd.pod`:
        //   seqRecord DOL0 (INLINK) / LNK0 (OUTLINK) / DOLA / DOLF / LNKF
        assert_eq!(dbf_link_class("seq", "DOL0"), Some(DbfLinkClass::InLink));
        assert_eq!(dbf_link_class("seq", "LNK0"), Some(DbfLinkClass::OutLink));
        assert_eq!(dbf_link_class("seq", "DOLA"), Some(DbfLinkClass::InLink));
        assert_eq!(dbf_link_class("seq", "DOLF"), Some(DbfLinkClass::InLink));
        assert_eq!(dbf_link_class("seq", "LNKF"), Some(DbfLinkClass::OutLink));
        //   selRecord NVL (INLINK); histogramRecord SVL (INLINK)
        assert_eq!(dbf_link_class("sel", "NVL"), Some(DbfLinkClass::InLink));
        assert_eq!(
            dbf_link_class("histogram", "SVL"),
            Some(DbfLinkClass::InLink)
        );
        //   calc/aSub INPA..INPU (INLINK); fanout/aSub OUTA (OUTLINK)
        assert_eq!(dbf_link_class("calc", "INPA"), Some(DbfLinkClass::InLink));
        assert_eq!(dbf_link_class("aSub", "INPU"), Some(DbfLinkClass::InLink));
        assert_eq!(
            dbf_link_class("fanout", "OUTA"),
            Some(DbfLinkClass::OutLink)
        );
        //   printf INP0..INP9 (INLINK)
        assert_eq!(dbf_link_class("printf", "INP0"), Some(DbfLinkClass::InLink));
    }

    #[test]
    fn siol_class_depends_on_record_direction() {
        // boRecord.dbd.pod:318 SIOL=DBF_OUTLINK; ai/bi SIOL=DBF_INLINK.
        assert_eq!(dbf_link_class("bo", "SIOL"), Some(DbfLinkClass::OutLink));
        assert_eq!(dbf_link_class("ao", "SIOL"), Some(DbfLinkClass::OutLink));
        assert_eq!(dbf_link_class("ai", "SIOL"), Some(DbfLinkClass::InLink));
        assert_eq!(dbf_link_class("bi", "SIOL"), Some(DbfLinkClass::InLink));
        // SIML is always DBF_INLINK regardless of direction.
        assert_eq!(dbf_link_class("bo", "SIML"), Some(DbfLinkClass::InLink));
        assert_eq!(dbf_link_class("ai", "SIML"), Some(DbfLinkClass::InLink));
    }

    /// `LNK0..LNKF` shares
    /// its spelling across two DBF classes — `fanoutRecord` declares the
    /// family `DBF_FWDLINK`, while `seqRecord`/`sseqRecord` declare it
    /// `DBF_OUTLINK`. The classifier must resolve by `record_type`, not
    /// collapse every `LNK*` to OutLink by prefix.
    #[test]
    fn lnk_class_depends_on_record_type() {
        // fanoutRecord.dbd.pod field(LNK0,DBF_FWDLINK) … field(LNKF,…).
        assert_eq!(
            dbf_link_class("fanout", "LNK0"),
            Some(DbfLinkClass::FwdLink),
            "fanout LNK0 is DBF_FWDLINK (16), not OUTLINK"
        );
        assert_eq!(
            dbf_link_class("fanout", "LNKF"),
            Some(DbfLinkClass::FwdLink),
            "fanout LNKF is DBF_FWDLINK (16), not OUTLINK"
        );
        // seqRecord.dbd.pod field(LNK0,DBF_OUTLINK): the default direction
        // for the shared spelling.
        assert_eq!(dbf_link_class("seq", "LNK0"), Some(DbfLinkClass::OutLink));
        assert_eq!(dbf_link_class("seq", "LNKF"), Some(DbfLinkClass::OutLink));
        // synApps sseqRecord LNK1..LNK9 are also DBF_OUTLINK (LNK10 is the
        // two-char spelling the one-alnum suffix rule deliberately rejects).
        assert_eq!(dbf_link_class("sseq", "LNK1"), Some(DbfLinkClass::OutLink));
        // fanout's dbCommon FLNK is still a forward link (unchanged).
        assert_eq!(
            dbf_link_class("fanout", "FLNK"),
            Some(DbfLinkClass::FwdLink)
        );
    }

    #[test]
    fn plain_value_fields_are_not_links() {
        for f in [
            "VAL", "EGU", "PREC", "HOPR", "RVAL", "DESC", "A", "B", "OVAL",
        ] {
            assert_eq!(dbf_link_class("ai", f), None, "{f} must not be a link");
        }
    }

    #[test]
    fn case_insensitive_and_trims() {
        assert_eq!(dbf_link_class("ai", "inp"), Some(DbfLinkClass::InLink));
        assert_eq!(dbf_link_class("ao", " OUT "), Some(DbfLinkClass::OutLink));
    }

    #[test]
    fn dbf_codes_and_range_match_pvxs() {
        assert_eq!(DbfLinkClass::InLink.dbf_type(), 14);
        assert_eq!(DbfLinkClass::OutLink.dbf_type(), 15);
        assert_eq!(DbfLinkClass::FwdLink.dbf_type(), 16);
        // pvxs groupsource.cpp:596-606 range check.
        assert!(is_link_dbf_type(DBF_INLINK));
        assert!(is_link_dbf_type(DBF_OUTLINK));
        assert!(is_link_dbf_type(DBF_FWDLINK));
        assert!(!is_link_dbf_type(13)); // DBF_DEVICE
        assert!(!is_link_dbf_type(17)); // DBF_NOACCESS
        assert!(!is_link_dbf_type(0)); // DBF_STRING
    }
}

#[cfg(test)]
mod dbr_text_tests {
    use super::*;

    #[test]
    fn resolves_every_type_name_to_its_code() {
        // Round-trip the whole table: each name resolves to its index.
        for (code, name) in DBR_TEXT.iter().enumerate() {
            assert_eq!(
                dbr_text_to_type(name),
                Some(code as u16),
                "{name} should resolve to {code}"
            );
        }
        // Boundary names spot-check (the cited High-finding values).
        assert_eq!(dbr_text_to_type("DBR_STRING"), Some(DBR_STRING));
        assert_eq!(dbr_text_to_type("DBR_TIME_FLOAT"), Some(DBR_TIME_FLOAT));
        assert_eq!(
            dbr_text_to_type("DBR_STSACK_STRING"),
            Some(DBR_STSACK_STRING)
        );
        assert_eq!(dbr_text_to_type("DBR_CLASS_NAME"), Some(DBR_CLASS_NAME));
    }

    #[test]
    fn is_case_sensitive_like_c_strcmp() {
        // C `dbr_text_to_type` uses `strcmp`, so lowercase does not
        // match — the C tools then revert to their plain request.
        assert_eq!(dbr_text_to_type("dbr_time_float"), None);
        assert_eq!(dbr_text_to_type("DBR_Time_Float"), None);
    }

    #[test]
    fn unknown_and_bare_family_names_do_not_match() {
        // Bare family names need the caller's `DBR_` retry — the raw
        // search rejects them, matching C's first-pass `strcmp`.
        assert_eq!(dbr_text_to_type("TIME_FLOAT"), None);
        assert_eq!(dbr_text_to_type("DOUBLE"), None);
        assert_eq!(dbr_text_to_type("DBR_NONSENSE"), None);
        assert_eq!(dbr_text_to_type(""), None);
    }
}