text: // Copyright 2004 The RE2 Authors.  All Rights Reserved.
  // Use of this source code is governed by a BSD-style
  // license that can be found in the LICENSE file.
  
  #include "thirdparty/re2-20130115/re2/stringpiece.h"
  #include "thirdparty/re2-20130115/util/util.h"
  
  using re2::StringPiece;
  
  std::ostream& operator<<(std::ostream& o, const StringPiece& piece) {
    o.write(piece.data(), piece.size());
    return o;
  }
  
  bool StringPiece::_equal(const StringPiece& x, const StringPiece& y) {
    int len = x.size();
    if (len != y.size()) {
      return false;
    }
    const char* p = x.data();
    const char* p2 = y.data();
    // Test last byte in case strings share large common prefix
    if ((len > 0) && (p[len-1] != p2[len-1])) return false;
    const char* p_limit = p + len;
    for (; p < p_limit; p++, p2++) {
      if (*p != *p2)
        return false;
    }
    return true;
  }
  
  void StringPiece::CopyToString(string* target) const {
    target->assign(ptr_, length_);
  }
  
  int StringPiece::copy(char* buf, size_type n, size_type pos) const {
    int ret = min(length_ - pos, n);
    memcpy(buf, ptr_ + pos, ret);
    return ret;
  }
  
  int StringPiece::find(const StringPiece& s, size_type pos) const {
    if (length_ < 0 || pos > static_cast<size_type>(length_))
      return npos;
  
    const char* result = std::search(ptr_ + pos, ptr_ + length_,
                                     s.ptr_, s.ptr_ + s.length_);
    const size_type xpos = result - ptr_;
    return xpos + s.length_ <= length_ ? xpos : npos;
  }
  
  int StringPiece::find(char c, size_type pos) const {
    if (length_ <= 0 || pos >= static_cast<size_type>(length_)) {
      return npos;
    }
    const char* result = std::find(ptr_ + pos, ptr_ + length_, c);
    return result != ptr_ + length_ ? result - ptr_ : npos;
  }
  
  int StringPiece::rfind(const StringPiece& s, size_type pos) const {
    if (length_ < s.length_) return npos;
    const size_t ulen = length_;
    if (s.length_ == 0) return min(ulen, pos);
  
    const char* last = ptr_ + min(ulen - s.length_, pos) + s.length_;
    const char* result = std::find_end(ptr_, last, s.ptr_, s.ptr_ + s.length_);
    return result != last ? result - ptr_ : npos;
  }
  
  int StringPiece::rfind(char c, size_type pos) const {
    if (length_ <= 0) return npos;
    for (int i = min(pos, static_cast<size_type>(length_ - 1));
         i >= 0; --i) {
      if (ptr_[i] == c) {
        return i;
      }
    }
    return npos;
  }
  
  StringPiece StringPiece::substr(size_type pos, size_type n) const {
    if (pos > length_) pos = length_;
    if (n > length_ - pos) n = length_ - pos;
    return StringPiece(ptr_ + pos, n);
  }
  
  const StringPiece::size_type StringPiece::npos = size_type(-1);
  