Initial release

thirdparty/libwebm/webm_parser/src/skip_parser.cc

@@ -0,0 +1,59 @@
+// Copyright (c) 2016 The WebM project authors. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the LICENSE file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS.  All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+#include "src/skip_parser.h"
+
+#include <cassert>
+#include <cstdint>
+
+#include "webm/element.h"
+#include "webm/reader.h"
+#include "webm/status.h"
+
+namespace webm {
+
+Status SkipParser::Init(const ElementMetadata& metadata,
+                        std::uint64_t max_size) {
+  assert(metadata.size == kUnknownElementSize || metadata.size <= max_size);
+
+  if (metadata.size == kUnknownElementSize) {
+    return Status(Status::kInvalidElementSize);
+  }
+
+  num_bytes_remaining_ = metadata.size;
+
+  return Status(Status::kOkCompleted);
+}
+
+Status SkipParser::Feed(Callback* callback, Reader* reader,
+                        std::uint64_t* num_bytes_read) {
+  assert(callback != nullptr);
+  assert(reader != nullptr);
+  assert(num_bytes_read != nullptr);
+
+  *num_bytes_read = 0;
+
+  if (num_bytes_remaining_ == 0) {
+    return Status(Status::kOkCompleted);
+  }
+
+  Status status;
+  do {
+    std::uint64_t local_num_bytes_read = 0;
+    status = reader->Skip(num_bytes_remaining_, &local_num_bytes_read);
+    assert((status.completed_ok() &&
+            local_num_bytes_read == num_bytes_remaining_) ||
+           (status.ok() && local_num_bytes_read < num_bytes_remaining_) ||
+           (!status.ok() && local_num_bytes_read == 0));
+    *num_bytes_read += local_num_bytes_read;
+    num_bytes_remaining_ -= local_num_bytes_read;
+  } while (status.code == Status::kOkPartial);
+
+  return status;
+}
+
+}  // namespace webm