diff --git a/lib/zip_source_file_win32.c b/lib/zip_source_file_win32.c
index 3c55d601f..2e63f5cf2 100644
--- a/lib/zip_source_file_win32.c
+++ b/lib/zip_source_file_win32.c
@@ -84,8 +84,7 @@ void _zip_win32_op_close(zip_source_file_context_t *ctx) {
 zip_int64_t _zip_win32_op_read(zip_source_file_context_t *ctx, void *buf, zip_uint64_t len) {
     DWORD i;
 
-    /* TODO: cap len to "DWORD_MAX" */
-    if (!ReadFile((HANDLE)ctx->f, buf, (DWORD)len, &i, NULL)) {
+    if (!ReadFile((HANDLE)ctx->f, buf, _zip_win32_clamp_length(len), &i, NULL)) {
         zip_error_set(&ctx->error, ZIP_ER_READ, _zip_win32_error_to_errno(GetLastError()));
         return -1;
     }
@@ -166,6 +165,11 @@ int _zip_win32_error_to_errno(DWORD win32err) {
 }
 
 
+DWORD _zip_win32_clamp_length(zip_uint64_t len) {
+    return (DWORD)ZIP_MIN(len, ZIP_UINT32_MAX);
+}
+
+
 static bool _zip_stat_win32(zip_source_file_context_t *ctx, zip_source_file_stat_t *st, HANDLE h) {
     FILETIME mtimeft;
     time_t mtime;
diff --git a/lib/zip_source_file_win32.h b/lib/zip_source_file_win32.h
index da691f0a4..1a0d2b7b0 100644
--- a/lib/zip_source_file_win32.h
+++ b/lib/zip_source_file_win32.h
@@ -67,6 +67,7 @@ typedef struct zip_win32_file_operations zip_win32_file_operations_t;
 extern zip_source_file_operations_t _zip_source_file_win32_named_ops;
 
 void _zip_win32_op_close(zip_source_file_context_t *ctx);
+DWORD _zip_win32_clamp_length(zip_uint64_t len);
 zip_int64_t _zip_win32_op_read(zip_source_file_context_t *ctx, void *buf, zip_uint64_t len);
 bool _zip_win32_op_seek(zip_source_file_context_t *ctx, void *f, zip_int64_t offset, int whence);
 zip_int64_t _zip_win32_op_tell(zip_source_file_context_t *ctx, void *f);
diff --git a/lib/zip_source_file_win32_named.c b/lib/zip_source_file_win32_named.c
index df3c41ce2..9fdfc99e6 100644
--- a/lib/zip_source_file_win32_named.c
+++ b/lib/zip_source_file_win32_named.c
@@ -241,13 +241,27 @@ static char *_zip_win32_named_op_string_duplicate(zip_source_file_context_t *ctx
 
 
 static zip_int64_t _zip_win32_named_op_write(zip_source_file_context_t *ctx, const void *data, zip_uint64_t len) {
+    const zip_uint8_t *buf = (const zip_uint8_t *)data;
+    zip_uint64_t written = 0;
     DWORD ret;
-    if (!WriteFile((HANDLE)ctx->fout, data, (DWORD)len, &ret, NULL) || ret != len) {
-        zip_error_set(&ctx->error, ZIP_ER_WRITE, _zip_win32_error_to_errno(GetLastError()));
-        return -1;
+
+    while (written < len) {
+        DWORD chunk = _zip_win32_clamp_length(len - written);
+        const void *chunk_data = written == 0 ? data : buf + written;
+
+        if (!WriteFile((HANDLE)ctx->fout, chunk_data, chunk, &ret, NULL)) {
+            zip_error_set(&ctx->error, ZIP_ER_WRITE, _zip_win32_error_to_errno(GetLastError()));
+            return -1;
+        }
+        if (ret == 0) {
+            zip_error_set(&ctx->error, ZIP_ER_WRITE, EINTR);
+            return -1;
+        }
+
+        written += ret;
     }
 
-    return (zip_int64_t)ret;
+    return (zip_int64_t)written;
 }