YugabyteDB (2.13.0.0-b42, bfc6a6643e7399ac8a0e81d06a3ee6d6571b33ab)

// Copyright 2004 and onwards Google Inc.

//

// The following only applies to changes made to this file as part of YugaByte development.

//

// Portions Copyright (c) YugaByte, Inc.

//

// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except

// in compliance with the License.  You may obtain a copy of the License at

//

// http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software distributed under the License

// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express

// or implied.  See the License for the specific language governing permissions and limitations

// under the License.

//

//

#include "yb/gutil/strings/stringpiece.h"

#include <string.h>

#include <algorithm>

#include <string>

#include <glog/logging.h>

#include "yb/gutil/hash/hash.h"

#include "yb/gutil/stl_util.h"

#include "yb/gutil/strings/memutil.h"

using std::copy;

using std::max;

using std::min;

using std::reverse;

using std::sort;

using std::swap;

using std::string;

namespace std {

  size_t hash<GStringPiece>::operator()(GStringPiece s) const {

    return HashTo32(s.data(), s.size());

  }

} // namespace std

std::ostream& operator<<(std::ostream& o, GStringPiece piece) {

  o.write(piece.data(), piece.size());

  return o;

}

GStringPiece::GStringPiece(GStringPiece x, size_type pos)

    : ptr_(x.ptr_ + pos), length_(x.length_ - pos) {

  DCHECK_LE(0, pos);

  DCHECK_LE(pos, x.length_);

}

GStringPiece::GStringPiece(GStringPiece x, size_type pos, size_type len)

    : ptr_(x.ptr_ + pos), length_(min(len, x.length_ - pos)) {

  DCHECK_LE(0, pos);

  DCHECK_LE(pos, x.length_);

  DCHECK_GE(len, 0);

}

void GStringPiece::CopyToString(string* target) const {

  STLAssignToString(target, ptr_, length_);

}

void GStringPiece::AppendToString(string* target) const {

  STLAppendToString(target, ptr_, length_);

}

GStringPiece::size_type GStringPiece::copy(char* buf, size_type n, size_type pos) const {

  size_type ret = min(length_ - pos, n);

  memcpy(buf, ptr_ + pos, ret);

  return ret;

}

bool GStringPiece::contains(GStringPiece s) const {

  return find(s, 0) != npos;

}

GStringPiece::size_type GStringPiece::find(GStringPiece s, size_type pos) const {

  if (length_ <= 0 || pos > static_cast<size_type>(length_)) {

    if (length_ == 0 && pos == 0 && s.length_ == 0) return 0;

    return npos;

  }

  const char *result = memmatch(ptr_ + pos, length_ - pos,

                                s.ptr_, s.length_);

  return result ? result - ptr_ : npos;

}

GStringPiece::size_type GStringPiece::find(char c, size_type pos) const {

  if (length_ <= 0 || pos >= static_cast<size_type>(length_)) {

    return npos;

  }

  const char* result = static_cast<const char*>(

      memchr(ptr_ + pos, c, length_ - pos));

  return result != nullptr ? result - ptr_ : npos;

}

GStringPiece::size_type GStringPiece::rfind(GStringPiece 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;

}

// Search range is [0..pos] inclusive.  If pos == npos, search everything.

GStringPiece::size_type GStringPiece::rfind(char c, size_type pos) const {

  // Note: memrchr() is not available on Windows.

  if (length_ <= 0) return npos;

  for (size_t i = min(pos + 1, length_); i > 0;) {

    --i;

    if (ptr_[i] == c) {

      return i;

    }

  }

  return npos;

}

// For each character in characters_wanted, sets the index corresponding

// to the ASCII code of that character to 1 in table.  This is used by

// the find_.*_of methods below to tell whether or not a character is in

// the lookup table in constant time.

// The argument `table' must be an array that is large enough to hold all

// the possible values of an unsigned char.  Thus it should be be declared

// as follows:

//   bool table[UCHAR_MAX + 1]

static inline void BuildLookupTable(GStringPiece characters_wanted,

                                    bool* table) {

  const size_t length = characters_wanted.length();

  const char* const data = characters_wanted.data();

  for (size_t i = 0; i < length; ++i) {

    table[static_cast<unsigned char>(data[i])] = true;

  }

}

GStringPiece::size_type GStringPiece::find_first_of(GStringPiece s, size_type pos) const {

  if (length_ <= 0 || s.length_ <= 0) {

    return npos;

  }

  // Avoid the cost of BuildLookupTable() for a single-character search.

  if (s.length_ == 1) return find_first_of(s.ptr_[0], pos);

  bool lookup[UCHAR_MAX + 1] = { false };

  BuildLookupTable(s, lookup);

  for (size_type i = pos; i < length_; ++i) {

    if (lookup[static_cast<unsigned char>(ptr_[i])]) {

      return i;

    }

  }

  return npos;

}

GStringPiece::size_type GStringPiece::find_first_not_of(GStringPiece s, size_type pos) const {

  if (length_ <= 0) return npos;

  if (s.length_ <= 0) return 0;

  // Avoid the cost of BuildLookupTable() for a single-character search.

  if (s.length_ == 1) return find_first_not_of(s.ptr_[0], pos);

  bool lookup[UCHAR_MAX + 1] = { false };

  BuildLookupTable(s, lookup);

  for (size_type i = pos; i < length_; ++i) {

    if (!lookup[static_cast<unsigned char>(ptr_[i])]) {

      return i;

    }

  }

  return npos;

}

GStringPiece::size_type GStringPiece::find_first_not_of(char c, size_type pos) const {

  if (length_ <= 0) return npos;

  for (; pos < length_; ++pos) {

    if (ptr_[pos] != c) {

      return pos;

    }

  }

  return npos;

}

GStringPiece::size_type GStringPiece::find_last_of(GStringPiece s, size_type pos) const {

  if (length_ <= 0 || s.length_ <= 0) return npos;

  // Avoid the cost of BuildLookupTable() for a single-character search.

  if (s.length_ == 1) return find_last_of(s.ptr_[0], pos);

  bool lookup[UCHAR_MAX + 1] = { false };

  BuildLookupTable(s, lookup);

  for (size_t i = min(pos + 1, length_); i > 0;) {

    --i;

    if (lookup[static_cast<unsigned char>(ptr_[i])]) {

      return i;

    }

  }

  return npos;

}

GStringPiece::size_type GStringPiece::find_last_not_of(GStringPiece s, size_type pos) const {

  if (length_ <= 0) return npos;

  size_type i = min(pos + 1, length_);

  if (s.length_ <= 0) return i - 1;

  // Avoid the cost of BuildLookupTable() for a single-character search.

  if (s.length_ == 1) return find_last_not_of(s.ptr_[0], pos);

  bool lookup[UCHAR_MAX + 1] = { false };

  BuildLookupTable(s, lookup);

  while (i > 0) {

    --i;

    if (!lookup[static_cast<unsigned char>(ptr_[i])]) {

      return i;

    }

  }

  return npos;

}

GStringPiece::size_type GStringPiece::find_last_not_of(char c, size_type pos) const {

  if (length_ <= 0) return npos;

  for (size_type i = min(pos + 1, length_); i > 0;) {

    --i;

    if (ptr_[i] != c) {

      return i;

    }

  }

  return npos;

}

GStringPiece GStringPiece::substr(size_type pos, size_type n) const {

  if (pos > length_) pos = length_;

  if (n > length_ - pos) n = length_ - pos;

  return GStringPiece(ptr_ + pos, n);

}

const GStringPiece::size_type GStringPiece::npos = size_type(-1);

size_t GStringPiece::hash() const {

  return HashStringThoroughly(data(), size());

}