Optimize G-code processing time by using M73OffsetTemplate for plate number offsets

tests/test_gcode_prepare_cache.py

@@ -71,6 +71,61 @@ class GcodePrepareCacheTest(unittest.TestCase):
             self.assertEqual(captured_gcode.count("G0 Y250 F3000 ;Patched"), 3)
             self.assertNotIn("G0 Y254 F3000", captured_gcode)
 
+    def test_repeated_copies_prepare_m73_template_once_per_member(self) -> None:
+        with tempfile.TemporaryDirectory() as directory:
+            root = Path(directory)
+            source_3mf = root / "source.3mf"
+            output_3mf = root / "out.3mf"
+            swap_gcode = root / "swap.gcode"
+            self.write_archive(source_3mf)
+            swap_gcode.write_text("; swap\nG1 X5\n", encoding="utf-8")
+
+            m73_template_calls = 0
+            captured_gcode = ""
+            original_prepare_m73 = builder.prepare_m73_offset_template
+
+            def count_m73_template_calls(text: str):
+                nonlocal m73_template_calls
+                m73_template_calls += 1
+                return original_prepare_m73(text)
+
+            def capture_gcode(
+                base_3mf: Path,
+                output_3mf: Path,
+                gcode_bytes: bytes,
+                sources: list[builder.PlateSource],
+                options: BuildOptions,
+            ) -> str:
+                nonlocal captured_gcode
+                captured_gcode = gcode_bytes.decode("utf-8")
+                return hashlib.md5(gcode_bytes).hexdigest()
+
+            options = BuildOptions(
+                swap_gcode=swap_gcode,
+                output_3mf=output_3mf,
+                apply_gcode_patches=False,
+                show_plate_number=True,
+                swap_after_final=False,
+                line_ending="lf",
+                add_preview_label=False,
+            )
+
+            with (
+                patch.object(builder, "prepare_m73_offset_template", side_effect=count_m73_template_calls),
+                patch.object(
+                    builder,
+                    "write_output_3mf",
+                    side_effect=capture_gcode,
+                ),
+            ):
+                result = builder.build_packed_3mf([PlateJob(source_3mf, 3)], options)
+
+            self.assertEqual(result.plate_count, 3)
+            self.assertEqual(m73_template_calls, 1)
+            self.assertIn("M73 P0 R6010", captured_gcode)
+            self.assertIn("M73 P0 R12010", captured_gcode)
+            self.assertIn("M73 P0 R18010", captured_gcode)
+
     @staticmethod
     def write_archive(path: Path) -> None:
         slice_info = """<?xml version="1.0" encoding="UTF-8"?>

tests/test_m73_offset_template.py

@@ -0,0 +1,42 @@
+from __future__ import annotations
+
+import unittest
+
+from a1_swap_mod_packer.gcode import M73_RE, apply_plate_number_offset, prepare_m73_offset_template
+
+
+class M73OffsetTemplateTest(unittest.TestCase):
+    def test_template_matches_previous_regex_replacement_semantics(self) -> None:
+        gcode = (
+            "M73 P0 R10\n"
+            "; M73 P0 R20\n"
+            " M73 P0 R30\n"
+            "M73 P50 R5999 ; comment\n"
+            "G1 X1\n"
+            "M73 P100 R0\n"
+        )
+
+        def previous_apply(text: str, plate_number: int) -> str:
+            minute_offset = plate_number * 100 * 60
+
+            def replace(match) -> str:
+                prefix = match.group(1)
+                remaining_minutes = int(match.group(2)) + minute_offset
+                suffix = match.group(3)
+                return f"{prefix}{remaining_minutes}{suffix}"
+
+            return M73_RE.sub(replace, text)
+
+        template = prepare_m73_offset_template(gcode)
+        for plate_number in (1, 2, 10):
+            self.assertEqual(template.apply(plate_number), previous_apply(gcode, plate_number))
+            self.assertEqual(apply_plate_number_offset(gcode, plate_number), previous_apply(gcode, plate_number))
+
+    def test_template_without_m73_matches_returns_original_text(self) -> None:
+        gcode = "G1 X1\n; M73 P0 R10\n"
+        template = prepare_m73_offset_template(gcode)
+        self.assertEqual(template.apply(3), gcode)
+
+
+if __name__ == "__main__":
+    unittest.main()