chromium/third_party/cld_3/src/src/script_span/offsetmap.h

// Copyright 2013 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//
// Author: [email protected] (Dick Sites)
//

#ifndef SCRIPT_SPAN_OFFSETMAP_H_
#define SCRIPT_SPAN_OFFSETMAP_H_

#include <string>                       // for string

#include "integral_types.h"             // for uint32

// ***************************** OffsetMap **************************
//
// An OffsetMap object is a container for a mapping from offsets in one text
// buffer A' to offsets in another text buffer A. It is most useful when A' is
// built from A via substitutions that occasionally do not preserve byte length.
//
// A series of operators are used to build the correspondence map, then
// calls can be made to map an offset in A' to an offset in A, or vice versa.
// The map starts with offset 0 in A corresponding to offset 0 in A'.
// The mapping is then built sequentially, adding on byte ranges that are
// identical in A and A', byte ranges that are inserted in A', and byte ranges
// that are deleted from A. All bytes beyond those specified when building the
// map are assumed to correspond, i.e. a Copy(infinity) is assumed at the
// end of the map.
//
// The internal data structure records positions at which bytes are added or
// deleted. Using the map is O(1) when increasing the A' or A offset
// monotonically, and O(n) when accessing random offsets, where n is the
// number of differences.
//

namespace chrome_lang_id {
namespace CLD2 {

class OffsetMap { … };

}  // namespace CLD2
}  // namespace chrome_lang_id

#endif  // SCRIPT_SPAN_OFFSETMAP_H_