like-predicate.h

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// Copyright 2012 Cloudera Inc.
//
// 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.


#ifndef IMPALA_EXPRS_LIKE_PREDICATE_H_
#define IMPALA_EXPRS_LIKE_PREDICATE_H_

#include <boost/scoped_ptr.hpp>
#include <re2/re2.h>
#include <string>

#include "exprs/predicate.h"
#include "gen-cpp/Exprs_types.h"
#include "runtime/string-search.h"
#include "udf/udf.h"

namespace re2 {
class RE2;
}

namespace impala {

class LikePredicate: public Predicate {
 public:
  ~LikePredicate();

 protected:
  friend class Expr;
  LikePredicate(const TExprNode& node);

 private:
  typedef impala_udf::BooleanVal (*LikePredicateFunction) (impala_udf::FunctionContext*,
      const impala_udf::StringVal&, const impala_udf::StringVal&);

  struct LikePredicateState {
    char escape_char_;

    LikePredicateFunction function_;

    std::string search_string_;

    StringValue search_string_sv_;

    StringSearch substring_pattern_;

    boost::scoped_ptr<re2::RE2> regex_;

    LikePredicateState() : escape_char_('\\') {
    }

    void SetSearchString(const std::string& search_string) {
      search_string_ = search_string;
      search_string_sv_ = StringValue(search_string);
      substring_pattern_ = StringSearch(&search_string_sv_);
    }
  };

  friend class OpcodeRegistry;

  static void LikePrepare(impala_udf::FunctionContext* context,
      impala_udf::FunctionContext::FunctionStateScope scope);

  static impala_udf::BooleanVal Like(impala_udf::FunctionContext* context,
      const impala_udf::StringVal& val, const impala_udf::StringVal& pattern);

  static void LikeClose(impala_udf::FunctionContext* context,
      impala_udf::FunctionContext::FunctionStateScope scope);

  static void RegexPrepare(impala_udf::FunctionContext* context,
      impala_udf::FunctionContext::FunctionStateScope scope);

  static impala_udf::BooleanVal Regex(impala_udf::FunctionContext* context,
      const impala_udf::StringVal& val, const impala_udf::StringVal& pattern);

  static void RegexClose(impala_udf::FunctionContext*,
      impala_udf::FunctionContext::FunctionStateScope scope);

  static impala_udf::BooleanVal RegexFn(impala_udf::FunctionContext* context,
      const impala_udf::StringVal& val, const impala_udf::StringVal& pattern);

  static impala_udf::BooleanVal LikeFn(impala_udf::FunctionContext* context,
      const impala_udf::StringVal& val, const impala_udf::StringVal& pattern);

  static impala_udf::BooleanVal ConstantSubstringFn(impala_udf::FunctionContext* context,
      const impala_udf::StringVal& val, const impala_udf::StringVal& pattern);

  static impala_udf::BooleanVal ConstantStartsWithFn(impala_udf::FunctionContext* context,
      const impala_udf::StringVal& val, const impala_udf::StringVal& pattern);

  static impala_udf::BooleanVal ConstantEndsWithFn(impala_udf::FunctionContext* context,
      const impala_udf::StringVal& val, const impala_udf::StringVal& pattern);

  static impala_udf::BooleanVal ConstantEqualsFn(impala_udf::FunctionContext* context,
      const impala_udf::StringVal& val, const impala_udf::StringVal& pattern);

  static impala_udf::BooleanVal ConstantRegexFnPartial(
      impala_udf::FunctionContext* context, const impala_udf::StringVal& val,
      const impala_udf::StringVal& pattern);

  static impala_udf::BooleanVal ConstantRegexFn(impala_udf::FunctionContext* context,
      const impala_udf::StringVal& val, const impala_udf::StringVal& pattern);

  static impala_udf::BooleanVal RegexMatch(impala_udf::FunctionContext* context,
      const impala_udf::StringVal& val, const impala_udf::StringVal& pattern,
      bool is_like_pattern);

  static void ConvertLikePattern(impala_udf::FunctionContext* context,
      const impala_udf::StringVal& pattern, std::string* re_pattern);
};

}  // namespace impala

#endif  // IMPALA_EXPRS_LIKE_PREDICATE_H_