From d6ac0c4aa2e64d59ed11c8964c83b580d9257489 Mon Sep 17 00:00:00 2001
From: Casey Clements <casey.clements@mongodb.com>
Date: Tue, 1 Oct 2024 09:19:26 -0400
Subject: [PATCH 1/2] Fix for ZSeries

---
 bson/binary.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/bson/binary.py b/bson/binary.py
index 47c52d4892..4fab4dd71e 100644
--- a/bson/binary.py
+++ b/bson/binary.py
@@ -432,7 +432,7 @@ def from_vector(
             raise NotImplementedError("%s not yet supported" % dtype)
 
         metadata = struct.pack("<sB", dtype.value, padding)
-        data = struct.pack(f"{len(vector)}{format_str}", *vector)
+        data = struct.pack(f"<{len(vector)}{format_str}", *vector)
         return cls(metadata + data, subtype=VECTOR_SUBTYPE)
 
     def as_vector(self) -> BinaryVector:
@@ -454,7 +454,7 @@ def as_vector(self) -> BinaryVector:
 
         if dtype == BinaryVectorDtype.INT8:
             dtype_format = "b"
-            format_string = f"{n_values}{dtype_format}"
+            format_string = f"<{n_values}{dtype_format}"
             vector = list(struct.unpack_from(format_string, self, position))
             return BinaryVector(vector, dtype, padding)
 

From 70d7a4146dbc1df1c65026164818144f2047edbc Mon Sep 17 00:00:00 2001
From: Casey Clements <casey.clements@mongodb.com>
Date: Tue, 1 Oct 2024 10:12:44 -0400
Subject: [PATCH 2/2] Endianness take II

---
 bson/binary.py | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/bson/binary.py b/bson/binary.py
index 4fab4dd71e..96b61b6dab 100644
--- a/bson/binary.py
+++ b/bson/binary.py
@@ -465,13 +465,16 @@ def as_vector(self) -> BinaryVector:
                 raise ValueError(
                     "Corrupt data. N bytes for a float32 vector must be a multiple of 4."
                 )
-            vector = list(struct.unpack_from(f"{n_values}f", self, position))
+            dtype_format = "f"
+            format_string = f"<{n_values}{dtype_format}"
+            vector = list(struct.unpack_from(format_string, self, position))
             return BinaryVector(vector, dtype, padding)
 
         elif dtype == BinaryVectorDtype.PACKED_BIT:
             # data packed as uint8
             dtype_format = "B"
-            unpacked_uint8s = list(struct.unpack_from(f"{n_values}{dtype_format}", self, position))
+            format_string = f"<{n_values}{dtype_format}"
+            unpacked_uint8s = list(struct.unpack_from(format_string, self, position))
             return BinaryVector(unpacked_uint8s, dtype, padding)
 
         else: