Added example

.github/workflows/test.yml

@@ -42,7 +42,9 @@ jobs:
       - uses: Swatinem/rust-cache@v1
       - name: Run
         shell: bash
-        run: ARROW2_IGNORE_PARQUET= cargo test --features full
+        run: |
+          cargo check --features full
+          cargo test --tests
 
   clippy:
     name: Clippy

Cargo.toml

@@ -80,7 +80,7 @@ crc = { version = "2", optional = true }
 async-stream = { version = "0.3.2", optional = true }
 
 # ORC support
-orc-format = { git = "https://github.com/DataEngineeringLabs/orc-format.git", branch = "iters", optional = true }
+orc-format = { version = "0.3.0", optional = true }
 
 # Arrow integration tests support
 serde = { version = "^1.0", features = ["rc"], optional = true }

examples/orc_read.rs

@@ -0,0 +1,55 @@
+use arrow2::array::*;
+use arrow2::error::Error;
+use arrow2::io::orc::{format, read};
+
+fn deserialize_column(path: &str, column_name: &str) -> Result<Box<dyn Array>, Error> {
+    // open the file
+    let mut reader = std::fs::File::open(path).unwrap();
+
+    // read its metadata (IO-bounded)
+    let metadata = format::read::read_metadata(&mut reader)?;
+
+    // infer its (Arrow) [`Schema`]
+    let schema = read::infer_schema(&metadata.footer)?;
+
+    // find the position of the column in the schema
+    let (pos, field) = schema
+        .fields
+        .iter()
+        .enumerate()
+        .find(|f| f.1.name == column_name)
+        .unwrap();
+
+    // pick a stripe (basically a set of rows)
+    let stripe = 0;
+
+    // read the stripe's footer (IO-bounded)
+    let footer = format::read::read_stripe_footer(&mut reader, &metadata, stripe, &mut vec![])?;
+
+    // read the column's data from the stripe (IO-bounded)
+    let data_type = field.data_type.clone();
+    let column = format::read::read_stripe_column(
+        &mut reader,
+        &metadata,
+        0,
+        footer,
+        // 1 because ORC schemas always start with a struct, which we ignore
+        1 + pos as u32,
+        vec![],
+    )?;
+
+    // finally, deserialize to Arrow (CPU-bounded)
+    read::deserialize(data_type, &column)
+}
+
+fn main() -> Result<(), Error> {
+    use std::env;
+    let args: Vec<String> = env::args().collect();
+
+    let file_path = &args[1];
+    let column = &args[2];
+
+    let array = deserialize_column(file_path, column)?;
+    println!("{array:?}");
+    Ok(())
+}

src/io/mod.rs

@@ -6,6 +6,7 @@
 pub mod odbc;
 
 #[cfg(feature = "io_orc")]
+#[cfg_attr(docsrs, doc(cfg(feature = "io_orc")))]
 pub mod orc;
 
 #[cfg(any(

tests/it/io/orc/read.rs

@@ -1,5 +1,4 @@
 use arrow2::array::*;
-use arrow2::datatypes::DataType;
 use arrow2::error::Error;
 use arrow2::io::orc::{format, read};