perf: Add basic parser benchmark test

Signed-off-by: 35V LG84 <[email protected]>

CREDITS.adoc

@@ -39,3 +39,8 @@ Build-tools (used to build Tackler):
 * https://github.com/RustSec/rustsec/tree/main/cargo-audit[cargo audit]
 * https://github.com/EmbarkStudios/cargo-deny[cargo deny]
 
+Benchmarks, flamegraphs, etc:
+
+* https://github.com/bheisler/criterion.rs[criterion]
+* https://github.com/flamegraph-rs/flamegraph[flamegraph]
+

tackler-core/Cargo.toml

@@ -56,4 +56,9 @@ tikv-jemallocator = { workspace = true }
 [dev-dependencies]
 rust_decimal_macros = { workspace = true }
 indoc = { workspace = true }
+criterion = { version = "0.5", features = ["html_reports"] }
+
+[[bench]]
+name = "parser_bench"
+harness = false
 

tackler-core/benches/parser_bench.rs

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2025 E257.FI
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+use criterion::{criterion_group, criterion_main, Criterion};
+use indoc::indoc;
+use tackler_core::kernel::Settings;
+use tackler_core::parser::string_to_txns;
+use tackler_rs::IndocUtils;
+
+fn criterion_benchmark(c: &mut Criterion) {
+    let mut settings = Settings::default();
+
+    #[rustfmt::skip]
+    let input = 
+        indoc!(
+            "|2024-12-31T23:58:59.123456789+02:00 (#001) 'bells 'n whistles
+             | # uuid: 506a2d55-2375-4d51-af3a-cf5021f04de9
+             | # tags: cef, first, second
+             | # location: geo:1.111,2.222,3.333
+             | ; first txn comment
+             | ; second txn comment
+             | e:d:f 26 bar·He_50L @ 1.25 EUR ; 32.50 EUR
+             | a:b:c
+             |
+             |").strip_margin();
+
+    c.bench_function("parser", |b| {
+        b.iter(|| {
+            let res = string_to_txns(input.as_ref(), &mut settings);
+            assert!(res.is_ok());
+        })
+    });
+}
+
+criterion_group!(benches, criterion_benchmark);
+criterion_main!(benches);