aboutsummaryrefslogtreecommitdiffhomepage
path: root/tensorflow/core/lib/io/iterator.h
diff options
context:
space:
mode:
authorGravatar Manjunath Kudlur <keveman@gmail.com>2015-11-06 16:27:58 -0800
committerGravatar Manjunath Kudlur <keveman@gmail.com>2015-11-06 16:27:58 -0800
commitf41959ccb2d9d4c722fe8fc3351401d53bcf4900 (patch)
treeef0ca22cb2a5ac4bdec9d080d8e0788a53ed496d /tensorflow/core/lib/io/iterator.h
TensorFlow: Initial commit of TensorFlow library.
TensorFlow is an open source software library for numerical computation using data flow graphs. Base CL: 107276108
Diffstat (limited to 'tensorflow/core/lib/io/iterator.h')
-rw-r--r--tensorflow/core/lib/io/iterator.h93
1 files changed, 93 insertions, 0 deletions
diff --git a/tensorflow/core/lib/io/iterator.h b/tensorflow/core/lib/io/iterator.h
new file mode 100644
index 0000000000..603a2f95fe
--- /dev/null
+++ b/tensorflow/core/lib/io/iterator.h
@@ -0,0 +1,93 @@
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+//
+// An iterator yields a sequence of key/value pairs from a source.
+// The following class defines the interface. Multiple implementations
+// are provided by this library. In particular, iterators are provided
+// to access the contents of a Table or a DB.
+//
+// Multiple threads can invoke const methods on an Iterator without
+// external synchronization, but if any of the threads may call a
+// non-const method, all threads accessing the same Iterator must use
+// external synchronization.
+
+#ifndef TENSORFLOW_LIB_IO_ITERATOR_H_
+#define TENSORFLOW_LIB_IO_ITERATOR_H_
+
+#include "tensorflow/core/lib/core/stringpiece.h"
+#include "tensorflow/core/public/status.h"
+
+namespace tensorflow {
+namespace table {
+
+class Iterator {
+ public:
+ Iterator();
+ virtual ~Iterator();
+
+ // An iterator is either positioned at a key/value pair, or
+ // not valid. This method returns true iff the iterator is valid.
+ virtual bool Valid() const = 0;
+
+ // Position at the first key in the source. The iterator is Valid()
+ // after this call iff the source is not empty.
+ virtual void SeekToFirst() = 0;
+
+ // Position at the first key in the source that is at or past target.
+ // The iterator is Valid() after this call iff the source contains
+ // an entry that comes at or past target.
+ virtual void Seek(const StringPiece& target) = 0;
+
+ // Moves to the next entry in the source. After this call, Valid() is
+ // true iff the iterator was not positioned at the last entry in the source.
+ // REQUIRES: Valid()
+ virtual void Next() = 0;
+
+ // Return the key for the current entry. The underlying storage for
+ // the returned slice is valid only until the next modification of
+ // the iterator.
+ // REQUIRES: Valid()
+ virtual StringPiece key() const = 0;
+
+ // Return the value for the current entry. The underlying storage for
+ // the returned slice is valid only until the next modification of
+ // the iterator.
+ // REQUIRES: Valid()
+ virtual StringPiece value() const = 0;
+
+ // If an error has occurred, return it. Else return an ok status.
+ virtual Status status() const = 0;
+
+ // Clients are allowed to register function/arg1/arg2 triples that
+ // will be invoked when this iterator is destroyed.
+ //
+ // Note that unlike all of the preceding methods, this method is
+ // not abstract and therefore clients should not override it.
+ typedef void (*CleanupFunction)(void* arg1, void* arg2);
+ void RegisterCleanup(CleanupFunction function, void* arg1, void* arg2);
+
+ private:
+ struct Cleanup {
+ CleanupFunction function;
+ void* arg1;
+ void* arg2;
+ Cleanup* next;
+ };
+ Cleanup cleanup_;
+
+ // No copying allowed
+ Iterator(const Iterator&);
+ void operator=(const Iterator&);
+};
+
+// Return an empty iterator (yields nothing).
+extern Iterator* NewEmptyIterator();
+
+// Return an empty iterator with the specified status.
+extern Iterator* NewErrorIterator(const Status& status);
+
+} // namespace table
+} // namespace tensorflow
+
+#endif // TENSORFLOW_LIB_IO_ITERATOR_H_