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      1 // Copyright (c) 2005, Google Inc.
      2 // All rights reserved.
      3 //
      4 // Redistribution and use in source and binary forms, with or without
      5 // modification, are permitted provided that the following conditions are
      6 // met:
      7 //
      8 //     * Redistributions of source code must retain the above copyright
      9 // notice, this list of conditions and the following disclaimer.
     10 //     * Redistributions in binary form must reproduce the above
     11 // copyright notice, this list of conditions and the following disclaimer
     12 // in the documentation and/or other materials provided with the
     13 // distribution.
     14 //     * Neither the name of Google Inc. nor the names of its
     15 // contributors may be used to endorse or promote products derived from
     16 // this software without specific prior written permission.
     17 //
     18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29 //
     30 // Author: Sanjay Ghemawat
     31 //
     32 // A string like object that points into another piece of memory.
     33 // Useful for providing an interface that allows clients to easily
     34 // pass in either a "const char*" or a "string".
     35 //
     36 // Arghh!  I wish C++ literals were automatically of type "string".
     37 
     38 #ifndef _PCRE_STRINGPIECE_H
     39 #define _PCRE_STRINGPIECE_H
     40 
     41 #include <cstring>
     42 #include <string>
     43 #include <iosfwd>    // for ostream forward-declaration
     44 
     45 #if @pcre_have_type_traits@
     46 #define HAVE_TYPE_TRAITS
     47 #include <type_traits.h>
     48 #elif @pcre_have_bits_type_traits@
     49 #define HAVE_TYPE_TRAITS
     50 #include <bits/type_traits.h>
     51 #endif
     52 
     53 #include <pcre.h>
     54 
     55 using std::memcmp;
     56 using std::strlen;
     57 using std::string;
     58 
     59 namespace pcrecpp {
     60 
     61 class PCRECPP_EXP_DEFN StringPiece {
     62  private:
     63   const char*   ptr_;
     64   int           length_;
     65 
     66  public:
     67   // We provide non-explicit singleton constructors so users can pass
     68   // in a "const char*" or a "string" wherever a "StringPiece" is
     69   // expected.
     70   StringPiece()
     71     : ptr_(NULL), length_(0) { }
     72   StringPiece(const char* str)
     73     : ptr_(str), length_(static_cast<int>(strlen(ptr_))) { }
     74   StringPiece(const unsigned char* str)
     75     : ptr_(reinterpret_cast<const char*>(str)),
     76       length_(static_cast<int>(strlen(ptr_))) { }
     77   StringPiece(const string& str)
     78     : ptr_(str.data()), length_(static_cast<int>(str.size())) { }
     79   StringPiece(const char* offset, int len)
     80     : ptr_(offset), length_(len) { }
     81 
     82   // data() may return a pointer to a buffer with embedded NULs, and the
     83   // returned buffer may or may not be null terminated.  Therefore it is
     84   // typically a mistake to pass data() to a routine that expects a NUL
     85   // terminated string.  Use "as_string().c_str()" if you really need to do
     86   // this.  Or better yet, change your routine so it does not rely on NUL
     87   // termination.
     88   const char* data() const { return ptr_; }
     89   int size() const { return length_; }
     90   bool empty() const { return length_ == 0; }
     91 
     92   void clear() { ptr_ = NULL; length_ = 0; }
     93   void set(const char* buffer, int len) { ptr_ = buffer; length_ = len; }
     94   void set(const char* str) {
     95     ptr_ = str;
     96     length_ = static_cast<int>(strlen(str));
     97   }
     98   void set(const void* buffer, int len) {
     99     ptr_ = reinterpret_cast<const char*>(buffer);
    100     length_ = len;
    101   }
    102 
    103   char operator[](int i) const { return ptr_[i]; }
    104 
    105   void remove_prefix(int n) {
    106     ptr_ += n;
    107     length_ -= n;
    108   }
    109 
    110   void remove_suffix(int n) {
    111     length_ -= n;
    112   }
    113 
    114   bool operator==(const StringPiece& x) const {
    115     return ((length_ == x.length_) &&
    116             (memcmp(ptr_, x.ptr_, length_) == 0));
    117   }
    118   bool operator!=(const StringPiece& x) const {
    119     return !(*this == x);
    120   }
    121 
    122 #define STRINGPIECE_BINARY_PREDICATE(cmp,auxcmp)                             \
    123   bool operator cmp (const StringPiece& x) const {                           \
    124     int r = memcmp(ptr_, x.ptr_, length_ < x.length_ ? length_ : x.length_); \
    125     return ((r auxcmp 0) || ((r == 0) && (length_ cmp x.length_)));          \
    126   }
    127   STRINGPIECE_BINARY_PREDICATE(<,  <);
    128   STRINGPIECE_BINARY_PREDICATE(<=, <);
    129   STRINGPIECE_BINARY_PREDICATE(>=, >);
    130   STRINGPIECE_BINARY_PREDICATE(>,  >);
    131 #undef STRINGPIECE_BINARY_PREDICATE
    132 
    133   int compare(const StringPiece& x) const {
    134     int r = memcmp(ptr_, x.ptr_, length_ < x.length_ ? length_ : x.length_);
    135     if (r == 0) {
    136       if (length_ < x.length_) r = -1;
    137       else if (length_ > x.length_) r = +1;
    138     }
    139     return r;
    140   }
    141 
    142   string as_string() const {
    143     return string(data(), size());
    144   }
    145 
    146   void CopyToString(string* target) const {
    147     target->assign(ptr_, length_);
    148   }
    149 
    150   // Does "this" start with "x"
    151   bool starts_with(const StringPiece& x) const {
    152     return ((length_ >= x.length_) && (memcmp(ptr_, x.ptr_, x.length_) == 0));
    153   }
    154 };
    155 
    156 }   // namespace pcrecpp
    157 
    158 // ------------------------------------------------------------------
    159 // Functions used to create STL containers that use StringPiece
    160 //  Remember that a StringPiece's lifetime had better be less than
    161 //  that of the underlying string or char*.  If it is not, then you
    162 //  cannot safely store a StringPiece into an STL container
    163 // ------------------------------------------------------------------
    164 
    165 #ifdef HAVE_TYPE_TRAITS
    166 // This makes vector<StringPiece> really fast for some STL implementations
    167 template<> struct __type_traits<pcrecpp::StringPiece> {
    168   typedef __true_type    has_trivial_default_constructor;
    169   typedef __true_type    has_trivial_copy_constructor;
    170   typedef __true_type    has_trivial_assignment_operator;
    171   typedef __true_type    has_trivial_destructor;
    172   typedef __true_type    is_POD_type;
    173 };
    174 #endif
    175 
    176 // allow StringPiece to be logged
    177 std::ostream& operator<<(std::ostream& o, const pcrecpp::StringPiece& piece);
    178 
    179 #endif /* _PCRE_STRINGPIECE_H */
    180