// Copyright 1999-2005 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 "util/strutil.h"

namespace re2 {

void PrefixSuccessor(std::string* prefix) {

  // We can increment the last character in the string and be done

  // unless that character is 255, in which case we have to erase the

  // last character and increment the previous character, unless that

  // is 255, etc. If the string is empty or consists entirely of

  // 255's, we just return the empty string.

  while (!prefix->empty()) {

    char& c = prefix->back();

    if (c == '\xff') {  // char literal avoids signed/unsigned.

      prefix->pop_back();

    } else {

      ++c;

      break;

    }

  }

}

}  // namespace re2