| // Copyright 2021 The Fuchsia Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include <lib/fidl/llcpp/message_storage.h> |
| #include <zircon/assert.h> |
| #include <zircon/compiler.h> |
| |
| namespace fidl { |
| |
| AnyMemoryResource MakeFidlAnyMemoryResource(fidl::BufferSpan buffer_span) { |
| uint8_t* data = buffer_span.data; |
| uint32_t capacity = buffer_span.capacity; |
| uint32_t used = 0; |
| |
| return [data, capacity, used](uint32_t num_bytes) mutable -> uint8_t* { |
| uint32_t used_original = used; |
| if (unlikely(add_overflow(used, num_bytes, &used))) { |
| // Allocation overflowed, revert to previous state. |
| used = used_original; |
| return nullptr; |
| } |
| if (used > capacity) { |
| // Allocation failed, revert to previous state. |
| used = used_original; |
| return nullptr; |
| } |
| return &data[used_original]; |
| }; |
| } |
| |
| } // namespace fidl |
