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 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.

 // Use of this source code is governed by a BSD-style license that can be

 // found in the LICENSE file.

 // Copied from strings/stringpiece.h with modifications

 //

 // A string-like object that points to a sized piece of memory.

 //

 // Functions or methods may use const StringPiece& parameters to accept either

 // a "const char*" or a "string" value that will be implicitly converted to

 // a StringPiece.  The implicit conversion means that it is often appropriate

 // to include this .h file in other files rather than forward-declaring

 // StringPiece as would be appropriate for most other Google classes.

 //

 // Systematic usage of StringPiece is encouraged as it will reduce unnecessary

 // conversions from "const char*" to "string" and back again.

 //

 #ifndef BASE_STRING_PIECE_H_

 #define BASE_STRING_PIECE_H_

 #include <algorithm>

 #include <iosfwd>

 #include <string>

 #include "base/basictypes.h"

 class StringPiece {

  public:

   typedef size_t size_type;

  private:

   const char*   ptr_;

   size_type     length_;

  public:

   // We provide non-explicit singleton constructors so users can pass

   // in a "const char*" or a "string" wherever a "StringPiece" is

   // expected.

   StringPiece() : ptr_(NULL), length_(0) { }

   StringPiece(const char* str)

     : ptr_(str), length_((str == NULL) ? 0 : strlen(str)) { }

   StringPiece(const std::string& str)

     : ptr_(str.data()), length_(str.size()) { }

   StringPiece(const char* offset, size_type len)

     : ptr_(offset), length_(len) { }

   // data() may return a pointer to a buffer with embedded NULs, and the

   // returned buffer may or may not be null terminated.  Therefore it is

   // typically a mistake to pass data() to a routine that expects a NUL

   // terminated string.

   const char* data() const { return ptr_; }

   size_type size() const { return length_; }

   size_type length() const { return length_; }

   bool empty() const { return length_ == 0; }

   void clear() { ptr_ = NULL; length_ = 0; }

   void set(const char* data, size_type len) { ptr_ = data; length_ = len; }

   void set(const char* str) {

     ptr_ = str;

     length_ = str ? strlen(str) : 0;

   }

   void set(const void* data, size_type len) {

     ptr_ = reinterpret_cast<const char*>(data);

     length_ = len;

   }

   char operator[](size_type i) const { return ptr_[i]; }

   void remove_prefix(size_type n) {

     ptr_ += n;

     length_ -= n;

   }

   void remove_suffix(size_type n) {

     length_ -= n;

   }

   int compare(const StringPiece& x) const {

     int r = wordmemcmp(ptr_, x.ptr_, std::min(length_, x.length_));

     if (r == 0) {

       if (length_ < x.length_) r = -1;

       else if (length_ > x.length_) r = +1;

     }

     return r;

   }

   std::string as_string() const {

     // std::string doesn't like to take a NULL pointer even with a 0 size.

     return std::string(!empty() ? data() : "", size());

   }

   void CopyToString(std::string* target) const;

   void AppendToString(std::string* target) const;

   // Does "this" start with "x"

   bool starts_with(const StringPiece& x) const {

     return ((length_ >= x.length_) &&

             (wordmemcmp(ptr_, x.ptr_, x.length_) == 0));

   }

   // Does "this" end with "x"

   bool ends_with(const StringPiece& x) const {

     return ((length_ >= x.length_) &&

             (wordmemcmp(ptr_ + (length_-x.length_), x.ptr_, x.length_) == 0));

   }

   // standard STL container boilerplate

   typedef char value_type;

   typedef const char* pointer;

   typedef const char& reference;

   typedef const char& const_reference;

   typedef ptrdiff_t difference_type;

   static const size_type npos;

   typedef const char* const_iterator;

   typedef const char* iterator;

   typedef std::reverse_iterator<const_iterator> const_reverse_iterator;

   typedef std::reverse_iterator<iterator> reverse_iterator;

   iterator begin() const { return ptr_; }

   iterator end() const { return ptr_ + length_; }

   const_reverse_iterator rbegin() const {

     return const_reverse_iterator(ptr_ + length_);

   }

   const_reverse_iterator rend() const {

     return const_reverse_iterator(ptr_);

   }

   size_type max_size() const { return length_; }

   size_type capacity() const { return length_; }

   size_type copy(char* buf, size_type n, size_type pos = 0) const;

   size_type find(const StringPiece& s, size_type pos = 0) const;

   size_type find(char c, size_type pos = 0) const;

   size_type rfind(const StringPiece& s, size_type pos = npos) const;

   size_type rfind(char c, size_type pos = npos) const;

   size_type find_first_of(const StringPiece& s, size_type pos = 0) const;

   size_type find_first_of(char c, size_type pos = 0) const {

     return find(c, pos);

   }

   size_type find_first_not_of(const StringPiece& s, size_type pos = 0) const;

   size_type find_first_not_of(char c, size_type pos = 0) const;

   size_type find_last_of(const StringPiece& s, size_type pos = npos) const;

   size_type find_last_of(char c, size_type pos = npos) const {

     return rfind(c, pos);

   }

   size_type find_last_not_of(const StringPiece& s, size_type pos = npos) const;

   size_type find_last_not_of(char c, size_type pos = npos) const;

   StringPiece substr(size_type pos, size_type n = npos) const;

   static int wordmemcmp(const char* p, const char* p2, size_type N) {

     return memcmp(p, p2, N);

   }

 };

 bool operator==(const ::StringPiece& x, const ::StringPiece& y);

 inline bool operator!=(const ::StringPiece& x, const ::StringPiece& y) {

   return !(x == y);

 }

 inline bool operator<(const ::StringPiece& x, const ::StringPiece& y) {

   const int r = ::StringPiece::wordmemcmp(x.data(), y.data(),

                                         std::min(x.size(), y.size()));

   return ((r < 0) || ((r == 0) && (x.size() < y.size())));

 }

 inline bool operator>(const ::StringPiece& x, const ::StringPiece& y) {

   return y < x;

 }

 inline bool operator<=(const ::StringPiece& x, const ::StringPiece& y) {

   return !(x > y);

 }

 inline bool operator>=(const ::StringPiece& x, const ::StringPiece& y) {

   return !(x < y);

 }

 // allow StringPiece to be logged (needed for unit testing).

 extern std::ostream& operator<<(std::ostream& o, const ::StringPiece& piece);

 #endif  // BASE_STRING_PIECE_H_