rust: add a new deserializer version (#3)

.github/workflows/bench.yml

@@ -5,9 +5,6 @@ on:
     branches: [ "main" ]
   pull_request:
     branches: [ "*" ]
-    paths:
-        - '.github/**-java.yml'
-        - 'java/**'
 
 jobs:
   bench:
@@ -18,7 +15,10 @@ jobs:
     - name: setup-files
       run: ./uncompress.sh
 
-    - name: rust/benchmark
+    - name: rust/benchmark/v2
+      run: cd rust/serdejsonbench && cargo build -r --examples && ./target/release/examples/bench --console --times 10 --method v2
+
+    - name: rust/benchmark/v1
       run: cd rust/serdejsonbench && cargo build -r --examples && ./target/release/examples/bench --console --times 10
 
     - uses: actions/setup-dotnet@v3

rust/serdejsonbench/examples/bench.rs

@@ -1,36 +1,70 @@
-use serdejsonbench::JsonIterator;
-use std::{io::Write, time::Instant};
-
-fn parse() {
-    let iter = JsonIterator::new(r#"../../json/256MB.json"#.into());
-    let mut count = 0;
-    for json in iter {
-        let json = json.unwrap();
-        assert_eq!("FULL", json.delta_mode);
-        count = count + 1;
-    }
-    assert_eq!(68495, count);
-}
-
-fn main() {
-    let args: Vec<String> = std::env::args().skip(1).collect();
-
-    if args.len() == 3 && args[0] == "--console" && args[1] == "--times" {
-        let now = Instant::now();
-        let times: u32 = args[2].as_str().parse().unwrap();
-
-        for _ in 0..times {
-            print!(".");
-            std::io::stdout().flush().unwrap();
-            parse();
-        }
-
-        let elapsed = now.elapsed().as_millis();
-        let avg = elapsed / u128::from(times);
-        println!("done in {elapsed}ms avg {avg}ms");
-    } else {
-        panic!("bad arguments {args:?}")
-    }
-
-    println!("done");
-}
+use serdejsonbench::JsonIterator;
+use serdejsonbench::{iter_json_array, Json};
+use std::fs::File;
+use std::{io::Write, time::Instant};
+
+use std::io::BufReader;
+
+fn parsev2() {
+    let reader = BufReader::with_capacity(8192, File::open(r#"../../json/256MB.json"#).unwrap());
+    let iter = iter_json_array(reader);
+    let mut count = 0;
+    for json in iter {
+        let json: Json = json.unwrap();
+        assert_eq!("FULL", json.delta_mode);
+        count = count + 1;
+    }
+    assert_eq!(68495, count);
+}
+
+fn parse() {
+    let iter = JsonIterator::new(r#"../../json/256MB.json"#.into());
+    let mut count = 0;
+    for json in iter {
+        let json = json.unwrap();
+        assert_eq!("FULL", json.delta_mode);
+        count = count + 1;
+    }
+    assert_eq!(68495, count);
+}
+
+enum Method {
+    V1,
+    V2,
+}
+
+fn main() {
+    let args: Vec<String> = std::env::args().skip(1).collect();
+
+    if args.len() > 2 && args[0] == "--console" && args[1] == "--times" {
+        let now = Instant::now();
+        let times: u32 = args[2].as_str().parse().unwrap();
+
+        let method = if args.len() > 4 && args[3] == "--method" && args[4] == "v2" {
+            println!("v2 version");
+            Method::V2
+        } else {
+            println!("v1 version");
+            Method::V1
+        };
+
+        let parse = match method {
+            Method::V1 => parse,
+            Method::V2 => parsev2,
+        };
+
+        for _ in 0..times {
+            print!(".");
+            std::io::stdout().flush().unwrap();
+            parse();
+        }
+
+        let elapsed = now.elapsed().as_millis();
+        let avg = elapsed / u128::from(times);
+        println!("done in {elapsed}ms avg {avg}ms");
+    } else {
+        panic!("bad arguments {args:?}")
+    }
+
+    println!("done");
+}

rust/serdejsonbench/examples/serde_json_stream_deserializer.rs

@@ -1,22 +1,20 @@
-//https://github.com/serde-rs/json/issues/404#issuecomment-674293399
-
-use serdejsonbench::JsonIterator;
-
-fn main() -> std::io::Result<()> {
-    let iter = JsonIterator::new(
-        r#"../../json/256MB.json"#.into(),
-    );
-    let mut count = 0;
-    for json in iter {
-        let json = json.unwrap();
-        assert_eq!("FULL", json.delta_mode);
-        count = count + 1;
-        if count % 1000 == 0 {
-            println!("{count}");
-        }
-    }
-
-    assert_eq!(68495, count);
-    println!("done");
-    Ok(())
-}
+//https://github.com/serde-rs/json/issues/404#issuecomment-674293399
+
+use serdejsonbench::JsonIterator;
+
+fn main() -> std::io::Result<()> {
+    let iter = JsonIterator::new(r#"../../json/256MB.json"#.into());
+    let mut count = 0;
+    for json in iter {
+        let json = json.unwrap();
+        assert_eq!("FULL", json.delta_mode);
+        count = count + 1;
+        if count % 1000 == 0 {
+            println!("{count}");
+        }
+    }
+
+    assert_eq!(68495, count);
+    println!("done");
+    Ok(())
+}

rust/serdejsonbench/examples/stream_deserializer_api_example.rs

@@ -1,11 +1,11 @@
-use serde_json::{Deserializer, Value};
-
-fn main() {
-    let data = "{\"k\": 3}1\"cool\"\"stuff\" 3{}  [0, 1, 2]";
-
-    let stream = Deserializer::from_str(data).into_iter::<Value>();
-
-    for value in stream {
-        println!("{}", value.unwrap());
-    }
-}
+use serde_json::{Deserializer, Value};
+
+fn main() {
+    let data = "{\"k\": 3}1\"cool\"\"stuff\" 3{}  [0, 1, 2]";
+
+    let stream = Deserializer::from_str(data).into_iter::<Value>();
+
+    for value in stream {
+        println!("{}", value.unwrap());
+    }
+}

rust/serdejsonbench/src/lib.rs

@@ -1,9 +1,13 @@
-//https://github.com/serde-rs/json/issues/404#issuecomment-674293399
-mod types;
-pub use types::Json;
-
-mod serde_json_stream_deserializer;
-pub use serde_json_stream_deserializer::JsonIterator;
-
-mod serde_json_simple_deserializer;
-pub use serde_json_simple_deserializer::{read_from_file, readone_from_file};
+//https://github.com/serde-rs/json/issues/404#issuecomment-674293399
+mod types;
+pub use types::Json;
+
+mod serde_json_stream_deserializer;
+pub use serde_json_stream_deserializer::JsonIterator;
+
+mod serde_json_simple_deserializer;
+pub use serde_json_simple_deserializer::{read_from_file, readone_from_file};
+
+mod serde_json_stream_deserializer2;
+
+pub use serde_json_stream_deserializer2::iter_json_array;

rust/serdejsonbench/src/serde_json_stream_deserializer2.rs

@@ -0,0 +1,59 @@
+// https://github.com/serde-rs/json/issues/404#issuecomment-892957228
+use serde::de::DeserializeOwned;
+use serde_json::{self, Deserializer};
+use std::io::{self, Read};
+
+fn read_skipping_ws(mut reader: impl Read) -> io::Result<u8> {
+    loop {
+        let mut byte = 0u8;
+        reader.read_exact(std::slice::from_mut(&mut byte))?;
+        if !byte.is_ascii_whitespace() {
+            return Ok(byte);
+        }
+    }
+}
+
+fn invalid_data(msg: &str) -> io::Error {
+    io::Error::new(io::ErrorKind::InvalidData, msg)
+}
+
+fn deserialize_single<T: DeserializeOwned, R: Read>(reader: R) -> io::Result<T> {
+    let next_obj = Deserializer::from_reader(reader).into_iter::<T>().next();
+    match next_obj {
+        Some(result) => result.map_err(Into::into),
+        None => Err(invalid_data("premature EOF")),
+    }
+}
+
+fn yield_next_obj<T: DeserializeOwned, R: Read>(
+    mut reader: R,
+    at_start: &mut bool,
+) -> io::Result<Option<T>> {
+    if !*at_start {
+        *at_start = true;
+        if read_skipping_ws(&mut reader)? == b'[' {
+            // read the next char to see if the array is empty
+            let peek = read_skipping_ws(&mut reader)?;
+            if peek == b']' {
+                Ok(None)
+            } else {
+                deserialize_single(io::Cursor::new([peek]).chain(reader)).map(Some)
+            }
+        } else {
+            Err(invalid_data("`[` not found"))
+        }
+    } else {
+        match read_skipping_ws(&mut reader)? {
+            b',' => deserialize_single(reader).map(Some),
+            b']' => Ok(None),
+            _ => Err(invalid_data("`,` or `]` not found")),
+        }
+    }
+}
+
+pub fn iter_json_array<T: DeserializeOwned, R: Read>(
+    mut reader: R,
+) -> impl Iterator<Item = Result<T, io::Error>> {
+    let mut at_start = false;
+    std::iter::from_fn(move || yield_next_obj(&mut reader, &mut at_start).transpose())
+}