fix: Add Windows support for ntohl/ntohs with platform-specific headers

Replace POSIX-specific arpa/inet.h with conditional compilation that uses
winsock2.h on Windows and arpa/inet.h on POSIX systems.

This ensures the driver can be compiled on Windows without modification.

Changes:
- cassandra/cython_marshal.pyx: Add platform detection for ntohs/ntohl
- cassandra/ioutils.pyx: Add platform detection for ntohl

Signed-off-by: Yaniv Kaul <yaniv.kaul@scylladb.com>

Author: mykaul

cassandra/cython_marshal.pyx

@@ -20,9 +20,17 @@ from libc.string cimport memcpy
 from cassandra.buffer cimport Buffer, buf_read, to_bytes
 
 # Use ntohs/ntohl for efficient big-endian to native conversion (single bswap instruction on x86)
-cdef extern from "arpa/inet.h" nogil:
-    uint16_t ntohs(uint16_t netshort)
-    uint32_t ntohl(uint32_t netlong)
+# Platform-specific header: arpa/inet.h on POSIX, winsock2.h on Windows
+cdef extern from *:
+    """
+    #ifdef _WIN32
+        #include <winsock2.h>
+    #else
+        #include <arpa/inet.h>
+    #endif
+    """
+    uint16_t ntohs(uint16_t netshort) nogil
+    uint32_t ntohl(uint32_t netlong) nogil
 
 cdef bint is_little_endian
 from cassandra.util import is_little_endian

cassandra/ioutils.pyx

@@ -19,8 +19,16 @@ from libc.stdint cimport int32_t, uint32_t
 from cassandra.bytesio cimport BytesIOReader
 
 # Use ntohl for efficient big-endian to native conversion (single bswap instruction)
-cdef extern from "arpa/inet.h" nogil:
-    uint32_t ntohl(uint32_t netlong)
+# Platform-specific header: arpa/inet.h on POSIX, winsock2.h on Windows
+cdef extern from *:
+    """
+    #ifdef _WIN32
+        #include <winsock2.h>
+    #else
+        #include <arpa/inet.h>
+    #endif
+    """
+    uint32_t ntohl(uint32_t netlong) nogil
 
 
 cdef inline int get_buf(BytesIOReader reader, Buffer *buf_out) except -1: