Class StringPiece

Bcore/src/main/cpp/base/stringpiece.h:34–219

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

// to include this .h file in other files rather than forward-declaring
// StringPiece as would be appropriate for most other Google classes.
class StringPiece {
 public:
  // standard STL container boilerplate
  typedef char value_type;
  typedef const char* pointer;
  typedef const char& reference;
  typedef const char& const_reference;
  typedef size_t size_type;
  typedef ptrdiff_t difference_type;
  static constexpr size_type npos = size_type(-1);
  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;

  // We provide non-explicit singleton constructors so users can pass
  // in a "const char*" or a "string" wherever a "StringPiece" is
  // expected.
  StringPiece() : ptr_(nullptr), length_(0) { }
  StringPiece(const char* str)  // NOLINT implicit constructor desired
    : ptr_(str), length_((str == nullptr) ? 0 : strlen(str)) { }
  StringPiece(const std::string& str)  // NOLINT implicit constructor desired
    : ptr_(str.data()), length_(str.size()) { }
  StringPiece(const char* offset, size_t 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_ = nullptr;
    length_ = 0;
  }
  void set(const char* data_in, size_type len) {
    ptr_ = data_in;
    length_ = len;
  }
  void set(const char* str) {
    ptr_ = str;
    if (str != nullptr) {
      length_ = strlen(str);
    } else {
      length_ = 0;
    }
  }
  void set(const void* data_in, size_type len) {
    ptr_ = reinterpret_cast<const char*>(data_in);
    length_ = len;
  }

  char operator[](size_type i) const {
    DCHECK_LT(i, length_);
    return ptr_[i];