From 7ad7e49a09b384dd76b35922ee224d601ab3b9fd Mon Sep 17 00:00:00 2001
From: Rafal Praczyk <rafalmaciejpraczyk@gmail.com>
Date: Sun, 9 Aug 2026 12:47:30 +0200
Subject: [PATCH 1/3] perf(stdnum.pl): optimize PESEL & NIP validation checksum
 algorithms

---
 stdnum/pl/nip.py   | 4 +++-
 stdnum/pl/pesel.py | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/stdnum/pl/nip.py b/stdnum/pl/nip.py
index bfc7506e..622830bc 100644
--- a/stdnum/pl/nip.py
+++ b/stdnum/pl/nip.py
@@ -48,7 +48,9 @@ def compact(number: str) -> str:
 def checksum(number: str) -> int:
     """Calculate the checksum."""
     weights = (6, 5, 7, 2, 3, 4, 5, 6, 7, -1)
-    return sum(w * int(n) for w, n in zip(weights, number)) % 11
+    d = [ord(c) - 48 for c in number]
+    return sum(d[i] * weights[i] for i in range(len(d))) % 11
+
 
 
 def validate(number: str) -> str:
diff --git a/stdnum/pl/pesel.py b/stdnum/pl/pesel.py
index 38ff544e..a160b1a9 100644
--- a/stdnum/pl/pesel.py
+++ b/stdnum/pl/pesel.py
@@ -92,10 +92,12 @@ def calc_check_digit(number: str) -> str:
     """Calculate the check digit for organisations. The number passed
     should not have the check digit included."""
     weights = (1, 3, 7, 9, 1, 3, 7, 9, 1, 3)
-    check = sum(w * int(n) for w, n in zip(weights, number))
+    d = [ord(c) - 48 for c in number[:10]]
+    check = sum(d[i] * weights[i] for i in range(len(d)))
     return str((10 - check) % 10)
 
 
+
 def validate(number: str) -> str:
     """Check if the number is a valid national identification number. This
     checks the length, formatting and check digit."""

From bcd59d1f8764f1daf03924808364d58e36fe61a3 Mon Sep 17 00:00:00 2001
From: Rafal Praczyk <rafalmaciejpraczyk@gmail.com>
Date: Sun, 9 Aug 2026 12:51:08 +0200
Subject: [PATCH 2/3] style: fix flake8 E303 blank line spacing

---
 stdnum/pl/nip.py   | 1 -
 stdnum/pl/pesel.py | 1 -
 2 files changed, 2 deletions(-)

diff --git a/stdnum/pl/nip.py b/stdnum/pl/nip.py
index 622830bc..cda58baa 100644
--- a/stdnum/pl/nip.py
+++ b/stdnum/pl/nip.py
@@ -52,7 +52,6 @@ def checksum(number: str) -> int:
     return sum(d[i] * weights[i] for i in range(len(d))) % 11
 
 
-
 def validate(number: str) -> str:
     """Check if the number is a valid VAT number. This checks the length,
     formatting and check digit."""
diff --git a/stdnum/pl/pesel.py b/stdnum/pl/pesel.py
index a160b1a9..51ef19c7 100644
--- a/stdnum/pl/pesel.py
+++ b/stdnum/pl/pesel.py
@@ -97,7 +97,6 @@ def calc_check_digit(number: str) -> str:
     return str((10 - check) % 10)
 
 
-
 def validate(number: str) -> str:
     """Check if the number is a valid national identification number. This
     checks the length, formatting and check digit."""

From c9af059b0a4fb52ca81169fb44c2628ad01ac5e4 Mon Sep 17 00:00:00 2001
From: Rafal Praczyk <rafalmaciejpraczyk@gmail.com>
Date: Fri, 14 Aug 2026 23:45:34 +0200
Subject: [PATCH 3/3] perf(pl): use zero-allocation in-place accumulator loop
 for checksums

---
 stdnum/pl/nip.py   | 10 +++++++---
 stdnum/pl/pesel.py | 11 +++++++----
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/stdnum/pl/nip.py b/stdnum/pl/nip.py
index cda58baa..537356d8 100644
--- a/stdnum/pl/nip.py
+++ b/stdnum/pl/nip.py
@@ -45,11 +45,15 @@ def compact(number: str) -> str:
     return number
 
 
+_weights = (6, 5, 7, 2, 3, 4, 5, 6, 7, -1)
+
+
 def checksum(number: str) -> int:
     """Calculate the checksum."""
-    weights = (6, 5, 7, 2, 3, 4, 5, 6, 7, -1)
-    d = [ord(c) - 48 for c in number]
-    return sum(d[i] * weights[i] for i in range(len(d))) % 11
+    total = 0
+    for w, n in zip(_weights, number):
+        total += w * (ord(n) - 48)
+    return total % 11
 
 
 def validate(number: str) -> str:
diff --git a/stdnum/pl/pesel.py b/stdnum/pl/pesel.py
index 51ef19c7..e7d1fb33 100644
--- a/stdnum/pl/pesel.py
+++ b/stdnum/pl/pesel.py
@@ -88,13 +88,16 @@ def get_gender(number: str) -> str:
         return 'M'
 
 
+_weights = (1, 3, 7, 9, 1, 3, 7, 9, 1, 3)
+
+
 def calc_check_digit(number: str) -> str:
     """Calculate the check digit for organisations. The number passed
     should not have the check digit included."""
-    weights = (1, 3, 7, 9, 1, 3, 7, 9, 1, 3)
-    d = [ord(c) - 48 for c in number[:10]]
-    check = sum(d[i] * weights[i] for i in range(len(d)))
-    return str((10 - check) % 10)
+    total = 0
+    for w, n in zip(_weights, number):
+        total += w * (ord(n) - 48)
+    return str((10 - total) % 10)
 
 
 def validate(number: str) -> str: