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 // 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: dsites@google.com (Dick Sites)

 //

 #ifndef I18N_ENCODINGS_CLD2_INTERNAL_GETONESCRIPTSPAN_H_

 #define I18N_ENCODINGS_CLD2_INTERNAL_GETONESCRIPTSPAN_H_

 #include "integral_types.h"

 #include "langspan.h"

 #include "offsetmap.h"

 namespace CLD2 {

 static const int kMaxScriptBuffer = 40960;

 static const int kMaxScriptLowerBuffer = (kMaxScriptBuffer * 3) / 2;

 static const int kMaxScriptBytes = kMaxScriptBuffer - 32;   // Leave some room

 static const int kWithinScriptTail = 32;    // Stop at word space in last

                                             // N bytes of script buffer

 static inline bool IsContinuationByte(char c) {

   return static_cast<signed char>(c) < -64;

 }

 // Gets lscript number for letters; always returns

 //   0 (common script) for non-letters

 int GetUTF8LetterScriptNum(const char* src);

 // Update src pointer to point to next quadgram, +2..+5

 // Looks at src[0..4]

 const char* AdvanceQuad(const char* src);

 class ScriptScanner {

  public:

   ScriptScanner(const char* buffer, int buffer_length, bool is_plain_text);

   ScriptScanner(const char* buffer, int buffer_length, bool is_plain_text,

                 bool any_text, bool any_script);

   ~ScriptScanner();

   // Copy next run of same-script non-tag letters to buffer [NUL terminated]

   bool GetOneScriptSpan(LangSpan* span);

   // Force Latin and Cyrillic scripts to be lowercase

   void LowerScriptSpan(LangSpan* span);

   // Copy next run of same-script non-tag letters to buffer [NUL terminated]

   // Force Latin and Cyrillic scripts to be lowercase

   bool GetOneScriptSpanLower(LangSpan* span);

   // Copy next run of non-tag characters to buffer [NUL terminated]

   // This just removes tags and removes entities

   // Buffer has leading space

   bool GetOneTextSpan(LangSpan* span);

   // Maps byte offset in most recent GetOneScriptSpan/Lower

   // span->text [0..text_bytes] into an additional byte offset from

   // span->offset, to get back to corresponding text in the original

   // input buffer.

   // text_offset must be the first byte

   // of a UTF-8 character, or just beyond the last character. Normally this

   // routine is called with the first byte of an interesting range and

   // again with the first byte of the following range.

   int MapBack(int text_offset);

   const char* GetBufferStart() {return start_byte_;};

  private:

   // Skip over tags and non-letters

   int SkipToFrontOfSpan(const char* src, int len, int* script);

   const char* start_byte_;        // Starting byte of buffer to scan

   const char* next_byte_;         // First unscanned byte

   const char* next_byte_limit_;   // Last byte + 1

   int byte_length_;               // Bytes left: next_byte_limit_ - next_byte_

   bool is_plain_text_;            // true fo text, false for HTML

   char* script_buffer_;           // Holds text with expanded entities

   char* script_buffer_lower_;     // Holds lowercased text

   bool letters_marks_only_;       // To distinguish scriptspan of one

                                   // letters/marks vs. any mixture of text

   bool one_script_only_;          // To distinguish scriptspan of one

                                   // script vs. any mixture of scripts

   int exit_state_;                // For tag parser kTagParseTbl_0, based

                                   // on letters_marks_only_

  public :

   // Expose for debugging

   OffsetMap map2original_;    // map from script_buffer_ to buffer

   OffsetMap map2uplow_;       // map from script_buffer_lower_ to script_buffer_

 };

 }  // namespace CLD2

 #endif  // I18N_ENCODINGS_CLD2_INTERNAL_GETONESCRIPTSPAN_H_