Struct ReadStatMetadata 

pub struct ReadStatMetadata {

    pub row_count: i32,
    pub var_count: i32,
    pub table_name: String,
    pub file_label: String,
    pub file_encoding: String,
    pub version: i32,
    pub is64bit: i32,
    pub creation_time: String,
    pub modified_time: String,
    pub compression: ReadStatCompress,
    pub endianness: ReadStatEndian,
    pub vars: BTreeMap<i32, ReadStatVarMetadata>,
    pub schema: Schema,
}

File-level metadata extracted from a .sas7bdat file.

Populated by the handle_metadata and handle_variable FFI callbacks during parsing. After parsing, call read_metadata to populate all fields and build the Arrow [Schema].

Fields

row_count: i32

Number of rows (observations) in the dataset.

var_count: i32

Number of variables (columns) in the dataset.

table_name: String

Internal table name from the SAS file header.

file_label: String

User-assigned file label.

file_encoding: String

Character encoding of the file (e.g. "UTF-8", "WINDOWS-1252").

version: i32

SAS file format version number.

is64bit: i32

Whether the file uses 64-bit format (0 = 32-bit, 1 = 64-bit).

creation_time: String

File creation timestamp (formatted as YYYY-MM-DD HH:MM:SS).

modified_time: String

File modification timestamp (formatted as YYYY-MM-DD HH:MM:SS).

compression: ReadStatCompress

Compression method used in the file.

endianness: ReadStatEndian

Byte order (endianness) of the file.

vars: BTreeMap<i32, ReadStatVarMetadata>

Per-variable metadata, keyed by variable index.

schema: Schema

Arrow schema derived from variable types. Not serialized.

Implementations

impl ReadStatMetadata

pub fn new() -> Self

Creates a new ReadStatMetadata with default (empty) values.

fn initialize_schema(&self) -> Schema

pub fn read_metadata( &mut self, rsp: &ReadStatPath, skip_row_count: bool, ) -> Result<(), ReadStatError>

Parses metadata from the .sas7bdat file referenced by rsp.

Sets up the ReadStat C parser with metadata and variable handlers, then invokes parsing. On success, builds the Arrow [Schema] from the discovered variable types. If skip_row_count is true, sets a row limit of 1 to skip counting all rows (faster for metadata-only queries).

Errors

Returns ReadStatError if FFI parsing fails.

pub fn read_metadata_from_bytes( &mut self, bytes: &[u8], skip_row_count: bool, ) -> Result<(), ReadStatError>

Parses metadata from an in-memory byte slice containing .sas7bdat data.

Equivalent to read_metadata but reads from a &[u8] buffer instead of a file path. Useful for WASM targets, cloud storage, HTTP uploads, and testing without filesystem access.

Errors

Returns ReadStatError if FFI parsing fails.

Panics

Panics if the dummy path CString allocation fails (should never happen).

pub fn read_metadata_from_mmap( &mut self, path: &Path, skip_row_count: bool, ) -> Result<(), ReadStatError>

Parses metadata from a memory-mapped .sas7bdat file.

Opens the file at path and memory-maps it, avoiding explicit read syscalls. The OS loads pages on demand and manages caching automatically. This is especially beneficial for large files where it avoids copying file data through kernel buffers.

Safety

Memory mapping is safe as long as the file is not modified or truncated by another process while the map is active. This is the standard expectation for .sas7bdat files, which are read-only artifacts.

Errors

Returns ReadStatError if the file cannot be opened, mapped, or parsed.

pub fn parse_columns_file(path: &Path) -> Result<Vec<String>, ReadStatError>

Parses a columns file, returning column names.

Lines starting with # are treated as comments and blank lines are skipped. Each remaining line is trimmed and used as a column name.

Errors

Returns ReadStatError if the file cannot be read.

pub fn resolve_selected_columns( &self, columns: Option<Vec<String>>, ) -> Result<Option<BTreeMap<i32, i32>>, ReadStatError>

Validates column names against the dataset’s variables and returns a mapping of original variable index to new contiguous index.

Returns Ok(None) if columns is None (no filtering requested). Returns Err(ColumnsNotFound) if any requested names are not in the dataset.

Errors

Returns ReadStatError::ColumnsNotFound if any requested column names do not exist in the dataset.

pub fn filter_to_selected_columns(&self, mapping: &BTreeMap<i32, i32>) -> Self

Returns a new ReadStatMetadata with only the selected variables, re-keyed with contiguous indices starting from 0.

Constructs the result directly instead of cloning the full struct, avoiding a deep clone of unselected variables and the original schema.

Trait Implementations

impl Clone for ReadStatMetadata

fn clone(&self) -> ReadStatMetadata

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ReadStatMetadata

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ReadStatMetadata

fn default() -> Self

Returns the “default value” for a type.

impl Serialize for ReadStatMetadata

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.