cudf 0.3.1

Safe Rust bindings for NVIDIA libcudf -- GPU-accelerated DataFrame operations
Documentation 
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//! ORC I/O.

use crate::error::{CudfError, Result};
use crate::io::parquet::Compression;
use crate::table::{Table, TableWithMetadata};

pub struct OrcReader {
    path: String,
    columns: Vec<String>,
    skip_rows: i64,
    num_rows: i64,
}

impl OrcReader {
    pub fn new(path: impl Into<String>) -> Self {
        Self {
            path: path.into(),
            columns: vec![],
            skip_rows: -1,
            num_rows: -1,
        }
    }
    pub fn columns(mut self, cols: Vec<String>) -> Self {
        self.columns = cols;
        self
    }
    pub fn skip_rows(mut self, n: usize) -> Self {
        self.skip_rows = n as i64;
        self
    }
    pub fn num_rows(mut self, n: usize) -> Self {
        self.num_rows = n as i64;
        self
    }
    pub fn read(self) -> Result<Table> {
        let raw = cudf_cxx::io::orc::ffi::read_orc(
            &self.path,
            &self.columns,
            self.skip_rows,
            self.num_rows,
        )
        .map_err(CudfError::from_cxx)?;
        Ok(Table { inner: raw })
    }

    /// Read an ORC file, returning both the table and column names
    /// from the file schema metadata.
    pub fn read_with_metadata(self) -> Result<TableWithMetadata> {
        let raw = cudf_cxx::io::orc::ffi::read_orc_with_metadata(
            &self.path,
            &self.columns,
            self.skip_rows,
            self.num_rows,
        )
        .map_err(CudfError::from_cxx)?;
        TableWithMetadata::from_raw(raw)
    }
}

pub struct OrcWriter<'a> {
    table: &'a Table,
    path: String,
    compression: Compression,
}

impl<'a> OrcWriter<'a> {
    pub fn new(table: &'a Table, path: impl Into<String>) -> Self {
        Self {
            table,
            path: path.into(),
            compression: Compression::Snappy,
        }
    }
    pub fn compression(mut self, c: Compression) -> Self {
        self.compression = c;
        self
    }
    pub fn write(self) -> Result<()> {
        cudf_cxx::io::orc::ffi::write_orc(&self.table.inner, &self.path, self.compression as i32)
            .map_err(CudfError::from_cxx)
    }
}

pub fn read_orc(path: impl Into<String>) -> Result<Table> {
    OrcReader::new(path).read()
}
pub fn write_orc(table: &Table, path: impl Into<String>) -> Result<()> {
    OrcWriter::new(table, path).write()
}