Class StringPiece

be/src/gutil/strings/stringpiece.h:130–298

#include "gutil/hash/hash.h"

class StringPiece {
 private:
  const char*   ptr_;
  int           length_;

 public:
  // We provide non-explicit singleton constructors so users can pass
  // in a "const char*" or a "string" wherever a "StringPiece" is
  // expected.
  //
  // Style guide exception granted:
  // http://goto/style-guide-exception-20978288
  StringPiece() : ptr_(NULL), length_(0) {}
  StringPiece(const char* str)  // NOLINT(runtime/explicit)
      : ptr_(str), length_(0) {
    if (str != NULL) {
      size_t length = strlen(str);
      assert(length <= static_cast<size_t>(std::numeric_limits<int>::max()));
      length_ = static_cast<int>(length);
    }
  }
  StringPiece(const std::string& str)  // NOLINT(runtime/explicit)
      : ptr_(str.data()), length_(0) {
    size_t length = str.size();
    assert(length <= static_cast<size_t>(std::numeric_limits<int>::max()));
    length_ = static_cast<int>(length);
  }
  StringPiece(const char* offset, int len) : ptr_(offset), length_(len) {
    assert(len >= 0);
  }

  // Substring of another StringPiece.
  // pos must be non-negative and <= x.length().
  StringPiece(StringPiece x, int pos);
  // Substring of another StringPiece.
  // pos must be non-negative and <= x.length().
  // len must be non-negative and will be pinned to at most x.length() - pos.
  StringPiece(StringPiece x, int pos, int 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_; }
  int size() const { return length_; }
  int length() const { return length_; }
  bool empty() const { return length_ == 0; }

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

  void set(const char* data, int len) {
    assert(len >= 0);
    ptr_ = data;
    length_ = len;
  }