[Autoloop: perf-comparison] Iteration 408: add readFwf benchmark pair

Run: https://github.com/githubnext/tsb/actions/runs/29645946373

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: github-actions[bot]

benchmarks/pandas/bench_read_fwf.py

@@ -0,0 +1,37 @@
+"""Benchmark: read_fwf — parse a fixed-width formatted text file into a DataFrame.
+Dataset: 10,000 rows x 4 columns (id, name, value, flag).
+"""
+import json, time, io
+import numpy as np
+import pandas as pd
+
+ROWS = 10_000
+WARMUP = 3
+ITERATIONS = 10
+
+# Build fixed-width text matching the TypeScript benchmark
+lines = ["id    name      value     flag"]
+for i in range(ROWS):
+    id_col = str(i).rjust(6)
+    name_col = ("item" + str(i % 500)).ljust(10)
+    value_col = f"{np.sin(i * 0.01) * 1000:.3f}".rjust(10)
+    flag_col = ("Y" if i % 2 == 0 else "N").ljust(4)
+    lines.append(id_col + name_col + value_col + flag_col)
+text = "\n".join(lines)
+
+colspecs = [(0, 6), (6, 16), (16, 26), (26, 30)]
+
+for _ in range(WARMUP):
+    pd.read_fwf(io.StringIO(text), colspecs=colspecs, header=0)
+
+start = time.perf_counter()
+for _ in range(ITERATIONS):
+    pd.read_fwf(io.StringIO(text), colspecs=colspecs, header=0)
+total = (time.perf_counter() - start) * 1000
+
+print(json.dumps({
+    "function": "readFwf",
+    "mean_ms": total / ITERATIONS,
+    "iterations": ITERATIONS,
+    "total_ms": total,
+}))

benchmarks/tsb/bench_read_fwf.ts

@@ -0,0 +1,39 @@
+/**
+ * Benchmark: readFwf — parse a fixed-width formatted text file into a DataFrame.
+ * Dataset: 10,000 rows × 4 columns (id, name, value, flag).
+ */
+import { readFwf } from "../../src/index.js";
+
+const ROWS = 10_000;
+const WARMUP = 3;
+const ITERATIONS = 10;
+
+// Build a fixed-width text: id(6), name(10), value(10), flag(4)
+const lines: string[] = ["id    name      value     flag"];
+for (let i = 0; i < ROWS; i++) {
+  const id = String(i).padStart(6);
+  const name = ("item" + (i % 500)).padEnd(10);
+  const value = (Math.sin(i * 0.01) * 1000).toFixed(3).padStart(10);
+  const flag = (i % 2 === 0 ? "Y" : "N").padEnd(4);
+  lines.push(id + name + value + flag);
+}
+const text = lines.join("\n");
+
+for (let i = 0; i < WARMUP; i++) {
+  readFwf(text, { colspecs: [[0, 6], [6, 16], [16, 26], [26, 30]] });
+}
+
+const start = performance.now();
+for (let i = 0; i < ITERATIONS; i++) {
+  readFwf(text, { colspecs: [[0, 6], [6, 16], [16, 26], [26, 30]] });
+}
+const total = performance.now() - start;
+
+console.log(
+  JSON.stringify({
+    function: "readFwf",
+    mean_ms: total / ITERATIONS,
+    iterations: ITERATIONS,
+    total_ms: total,
+  }),
+);