diff --git a/cgo/sha1.go b/cgo/sha1.go
index dc8d21b..b32dada 100644
--- a/cgo/sha1.go
+++ b/cgo/sha1.go
@@ -65,3 +65,14 @@ func Sum(data []byte) ([]byte, bool) {
 
 	return d.sum()
 }
+
+func (d *digest) Write(p []byte) (nn int, err error) {
+	if len(p) == 0 {
+		return 0, nil
+	}
+
+	data := (*C.char)(unsafe.Pointer(&p[0]))
+	C.SHA1DCUpdate(&d.ctx, data, (C.size_t)(len(p)))
+
+	return len(p), nil
+}
diff --git a/cgo/sha1_nix.go b/cgo/sha1_nix.go
deleted file mode 100644
index 447e939..0000000
--- a/cgo/sha1_nix.go
+++ /dev/null
@@ -1,22 +0,0 @@
-//go:build !windows && !arm
-// +build !windows,!arm
-
-package cgo
-
-// #include <sha1.h>
-// #include <stdlib.h>
-// #include <stddef.h>
-import "C"
-
-import "unsafe"
-
-func (d *digest) Write(p []byte) (nn int, err error) {
-	if len(p) == 0 {
-		return 0, nil
-	}
-
-	data := (*C.char)(unsafe.Pointer(&p[0]))
-	C.SHA1DCUpdate(&d.ctx, data, (C.ulong)(len(p)))
-
-	return len(p), nil
-}
diff --git a/cgo/sha1_nix_armhf.go b/cgo/sha1_nix_armhf.go
deleted file mode 100644
index 80e3836..0000000
--- a/cgo/sha1_nix_armhf.go
+++ /dev/null
@@ -1,22 +0,0 @@
-//go:build !windows && arm
-// +build !windows,arm
-
-package cgo
-
-// #include <sha1.h>
-// #include <stdlib.h>
-// #include <stddef.h>
-import "C"
-
-import "unsafe"
-
-func (d *digest) Write(p []byte) (nn int, err error) {
-	if len(p) == 0 {
-		return 0, nil
-	}
-
-	data := (*C.char)(unsafe.Pointer(&p[0]))
-	C.SHA1DCUpdate(&d.ctx, data, (C.uint)(len(p)))
-
-	return len(p), nil
-}
diff --git a/cgo/sha1_windows.go b/cgo/sha1_windows.go
deleted file mode 100644
index 37f985b..0000000
--- a/cgo/sha1_windows.go
+++ /dev/null
@@ -1,22 +0,0 @@
-//go:build windows
-// +build windows
-
-package cgo
-
-// #include <sha1.h>
-// #include <stdlib.h>
-// #include <stddef.h>
-import "C"
-
-import "unsafe"
-
-func (d *digest) Write(p []byte) (nn int, err error) {
-	if len(p) == 0 {
-		return 0, nil
-	}
-
-	data := (*C.char)(unsafe.Pointer(&p[0]))
-	C.SHA1DCUpdate(&d.ctx, data, (C.ulonglong)(len(p)))
-
-	return len(p), nil
-}