pcre_stringpiece.h.in

   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 namespace pcrecpp {
  56
  57 using std::memcmp;
  58 using std::strlen;
  59 using std::string;
  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 PCRECPP_EXP_DECL std::ostream& operator<<(std::ostream& o,
 178                                           const pcrecpp::StringPiece& piece);
 179
 180 #endif /* _PCRE_STRINGPIECE_H */