From 870f41469025fc6e4ba0d16a4e634c79c571c50d Mon Sep 17 00:00:00 2001
From: Thomas Waldmann <tw@waldmann-edv.de>
Date: Thu, 20 Nov 2025 01:35:03 +0100
Subject: [PATCH] buzhash/buzhash64: initialise all-zero memory more
 efficiently

---
 src/borg/chunkers/buzhash.pyx   | 6 +++---
 src/borg/chunkers/buzhash64.pyx | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/borg/chunkers/buzhash.pyx b/src/borg/chunkers/buzhash.pyx
index 4453d511d..627d5ba62 100644
--- a/src/borg/chunkers/buzhash.pyx
+++ b/src/borg/chunkers/buzhash.pyx
@@ -7,7 +7,7 @@ import time
 from cpython.bytes cimport PyBytes_AsString
 from libc.stdint cimport uint8_t, uint32_t
 from libc.stdlib cimport malloc, free
-from libc.string cimport memcpy, memmove
+from libc.string cimport memcpy, memmove, memset
 
 from ..constants import CH_DATA, CH_ALLOC, CH_HOLE, zeros
 from .reader import FileReader, Chunk
@@ -199,8 +199,8 @@ cdef class Chunker:
                 # Copy data from chunk to our buffer
                 memcpy(self.data + self.position + self.remaining, <const unsigned char*>PyBytes_AsString(chunk.data), n)
             else:
-                # For holes, fill with zeros
-                memcpy(self.data + self.position + self.remaining, <const unsigned char*>PyBytes_AsString(zeros[:n]), n)
+                # For holes, fill with zeros using memset
+                memset(self.data + self.position + self.remaining, 0, n)
 
             self.remaining += n
             self.bytes_read += n
diff --git a/src/borg/chunkers/buzhash64.pyx b/src/borg/chunkers/buzhash64.pyx
index f16ddb3ef..c241e5845 100644
--- a/src/borg/chunkers/buzhash64.pyx
+++ b/src/borg/chunkers/buzhash64.pyx
@@ -8,7 +8,7 @@ import time
 from cpython.bytes cimport PyBytes_AsString
 from libc.stdint cimport uint8_t, uint64_t
 from libc.stdlib cimport malloc, free
-from libc.string cimport memcpy, memmove
+from libc.string cimport memcpy, memmove, memset
 
 from ..crypto.low_level import CSPRNG
 
@@ -176,8 +176,8 @@ cdef class ChunkerBuzHash64:
                 # Copy data from chunk to our buffer
                 memcpy(self.data + self.position + self.remaining, <const unsigned char*>PyBytes_AsString(chunk.data), n)
             else:
-                # For holes, fill with zeros
-                memcpy(self.data + self.position + self.remaining, <const unsigned char*>PyBytes_AsString(zeros[:n]), n)
+                # For holes, fill with zeros using memset
+                memset(self.data + self.position + self.remaining, 0, n)
 
             self.remaining += n
             self.bytes_read += n