base/i18n: Class for efficiently searching the same query over many texts.

base/i18n/string_search.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_I18N_STRING_SEARCH_H_
 #define BASE_I18N_STRING_SEARCH_H_
 
 #include "base/i18n/base_i18n_export.h"
 #include "base/strings/string16.h"
 
+struct UStringSearch;
+
 namespace base {
 namespace i18n {
 
 // Returns true if |in_this| contains |find_this|. If |match_index| or
 // |match_length| are non-NULL, they are assigned the start position and total
 // length of the match.
 //
 // Only differences between base letters are taken into consideration. Case and
 // accent differences are ignored. Please refer to 'primary level' in
 // http://userguide.icu-project.org/collation/concepts for additional details.
 BASE_I18N_EXPORT
     bool StringSearchIgnoringCaseAndAccents(const string16& find_this,
                                             const string16& in_this,
                                             size_t* match_index,
                                             size_t* match_length);
 
+// This class is for speeding up multiple StringSearchIgnoringCaseAndAccents()
+// with the same |find_this| argument. |find_this| is passed as the constructor
+// argument, and precomputation for searching is done only at that timing.
+class BASE_I18N_EXPORT FixedPatternStringSearchIgnoringCaseAndAccents {
+ public:
+  explicit FixedPatternStringSearchIgnoringCaseAndAccents(
+      const string16& find_this);
+  ~FixedPatternStringSearchIgnoringCaseAndAccents();
+
+  // Returns true if |in_this| contains |find_this|. If |match_index| or
+  // |match_length| are non-NULL, they are assigned the start position and total
+  // length of the match.
+  bool Search(const string16& in_this,
+              size_t* match_index,
+              size_t* match_length);
+
+ private:
+  string16 find_this_;
+  UStringSearch* search_;
+};
+
 }  // namespace i18n
 }  // namespace base
 
 #endif  // BASE_I18N_STRING_SEARCH_H_