[libc-commits] [clang] [libc] [libc] Support opaque FILE* on baremetal (PR #168931)

[Michael Jones via libc-commits]

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@@ -0,0 +1,33 @@
+//===-- Implementation of fread for baremetal -------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/stdio/fread.h"
+
+#include "hdr/types/FILE.h"
+#include "src/__support/common.h"
+#include "src/__support/libc_errno.h"
+#include "src/__support/macros/config.h"
+#include "src/stdio/baremetal/file_internal.h"
+
+#include <stddef.h>
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(size_t, fread,
+                   (void *__restrict buffer, size_t size, size_t nmemb,
+                    ::FILE *stream)) {
+  if (size == 0 || nmemb == 0)
+    return 0;
+  auto result =
+      read_internal(reinterpret_cast<char *>(buffer), size * nmemb, stream);
----------------
michaelrj-google wrote:

given that the expectation is this will be read into a buffer and both `size` and `nmemb` are `size_t` I'm not concerned with overflow. Normally `size_t` is `uint64`, meaning you'd need to try and read 2^64 bytes bytes before it was an issue.

https://github.com/llvm/llvm-project/pull/168931