From 113c446fc573dc59336f8bb7fb70a22f86639530 Mon Sep 17 00:00:00 2001
From: Daniele Varrazzo <daniele.varrazzo@gmail.com>
Date: Sun, 9 May 2021 23:17:59 +0200
Subject: [PATCH] Use faster C mod operator in Decimal dump

---
 psycopg3_c/psycopg3_c/types/numeric.pyx | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/psycopg3_c/psycopg3_c/types/numeric.pyx b/psycopg3_c/psycopg3_c/types/numeric.pyx
index 9cbf94d96..c0d8e7224 100644
--- a/psycopg3_c/psycopg3_c/types/numeric.pyx
+++ b/psycopg3_c/psycopg3_c/types/numeric.pyx
@@ -544,6 +544,7 @@ static const int pydigit_weights[] = {1000, 100, 10, 1};
     const int[4] pydigit_weights
 
 @cython.final
+@cython.cdivision(True)
 cdef class DecimalBinaryDumper(CDumper):
 
     format = PQ_BINARY
@@ -609,6 +610,9 @@ cdef class DecimalBinaryDumper(CDumper):
         # but without changing the digits tuple.
         cdef int wi = 0
         cdef int mod = (ndigits - dscale) % DEC_DIGITS
+        if mod < 0:
+            # the difference between C and Py % operator
+            mod += 4
         if mod:
             wi = DEC_DIGITS - mod
             ndigits += wi
-- 
2.47.2