github.com/maruel/nin@v0.0.0-20220112143044-f35891e3ce7e/src/string_piece.h (about)

     1  // Copyright 2011 Google Inc. All Rights Reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  #ifndef NINJA_STRINGPIECE_H_
    16  #define NINJA_STRINGPIECE_H_
    17  
    18  #include <string>
    19  
    20  #include <string.h>
    21  
    22  /// StringPiece represents a slice of a string whose memory is managed
    23  /// externally.  It is useful for reducing the number of std::strings
    24  /// we need to allocate.
    25  struct StringPiece {
    26    typedef const char* const_iterator;
    27  
    28    StringPiece() : str_(NULL), len_(0) {}
    29  
    30    /// The constructors intentionally allow for implicit conversions.
    31    StringPiece(const std::string& str) : str_(str.data()), len_(str.size()) {}
    32    StringPiece(const char* str) : str_(str), len_(strlen(str)) {}
    33  
    34    StringPiece(const char* str, size_t len) : str_(str), len_(len) {}
    35  
    36    bool operator==(const StringPiece& other) const {
    37      return len_ == other.len_ && memcmp(str_, other.str_, len_) == 0;
    38    }
    39  
    40    bool operator!=(const StringPiece& other) const {
    41      return !(*this == other);
    42    }
    43  
    44    /// Convert the slice into a full-fledged std::string, copying the
    45    /// data into a new string.
    46    std::string AsString() const {
    47      return len_ ? std::string(str_, len_) : std::string();
    48    }
    49  
    50    const_iterator begin() const {
    51      return str_;
    52    }
    53  
    54    const_iterator end() const {
    55      return str_ + len_;
    56    }
    57  
    58    char operator[](size_t pos) const {
    59      return str_[pos];
    60    }
    61  
    62    size_t size() const {
    63      return len_;
    64    }
    65  
    66    const char* str_;
    67    size_t len_;
    68  };
    69  
    70  #endif  // NINJA_STRINGPIECE_H_