sapling/eden/fs/utils/ChronoUnit.cpp

/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This software may be used and distributed according to the terms of the
 * GNU General Public License version 2.
 */

#include "eden/fs/utils/ChronoUnit.h"

/*
 * This file was originally generated by gperf-3.1, but then hand-tweaked
 * to work more nicely with folly::StringPiece.
 * https://www.gnu.org/software/gperf/
 *
 * C++ code produced by gperf version 3.1
 * Command-line: gperf eden/fs/utils/ChronoUnit.gperf
 * Computed positions: -k'1-3'
 */

using facebook::eden::ChronoUnit;
using folly::StringPiece;

namespace {

#define TOTAL_KEYWORDS 33
#define MIN_WORD_LENGTH 1
#define MAX_WORD_LENGTH 12
#define MIN_HASH_VALUE 1
#define MAX_HASH_VALUE 69
/* maximum key range = 69, duplicates = 0 */

class ChronoUnitPerfectHash {
 private:
  static inline unsigned int hash(StringPiece str);

 public:
  static const ChronoUnit* FOLLY_NULLABLE in_word_set(StringPiece str);
};

inline unsigned int ChronoUnitPerfectHash::hash(StringPiece str) {
  static constexpr std::array<unsigned char, 256> asso_values{
      70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70,
      70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70,
      70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70,
      70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70,
      70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70,
      70, 70, 70, 70, 70, 70, 70, 30, 70, 5,  35, 20, 70, 70, 20, 5,  70, 35,
      25, 5,  0,  0,  70, 70, 20, 0,  70, 10, 70, 0,  70, 0,  70, 70, 70, 70,
      70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70,
      70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70,
      70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70,
      70, 70, 70, 70, 70, 70, 70, 70, 0,  70, 70, 70, 70, 70, 70, 70, 70, 70,
      70, 70, 70, 70, 70, 70, 70, 70, 0,  70, 70, 70, 70, 70, 70, 70, 70, 70,
      70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70,
      70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70, 70,
      70, 70, 70, 70};
  unsigned int hval = str.size();

  switch (hval) {
    default:
      hval += asso_values[static_cast<unsigned char>(str[2])];
      FOLLY_FALLTHROUGH;
    case 2:
      hval += asso_values[static_cast<unsigned char>(str[1])];
      FOLLY_FALLTHROUGH;
    case 1:
      hval += asso_values[static_cast<unsigned char>(str[0])];
      break;
  }
  return hval;
}

const ChronoUnit* FOLLY_NULLABLE
ChronoUnitPerfectHash::in_word_set(StringPiece str) {
  static constexpr std::array<ChronoUnit, MAX_HASH_VALUE + 1> wordlist{
      {{"", 0, 0},
       {"s", 1, 1},
       {"ns", 1, 1000000000},
       {"\316\274s", 1, 1000000},
       {"", 0, 0},
       {"", 0, 0},
       {"m", 60, 1},
       {"ms", 1, 1000},
       {"mon", 2629746, 1},
       {"", 0, 0},
       {"month", 2629746, 1},
       {"months", 2629746, 1},
       {"us", 1, 1000000},
       {"min", 60, 1},
       {"", 0, 0},
       {"", 0, 0},
       {"minute", 60, 1},
       {"minutes", 60, 1},
       {"", 0, 0},
       {"", 0, 0},
       {"", 0, 0},
       {"h", 3600, 1},
       {"yr", 31556952, 1},
       {"", 0, 0},
       {"", 0, 0},
       {"", 0, 0},
       {"microsecond", 1, 1000000},
       {"microseconds", 1, 1000000},
       {"", 0, 0},
       {"", 0, 0},
       {"", 0, 0},
       {"second", 1, 1},
       {"seconds", 1, 1},
       {"", 0, 0},
       {"hour", 3600, 1},
       {"hours", 3600, 1},
       {"d", 86400, 1},
       {"wk", 604800, 1},
       {"", 0, 0},
       {"", 0, 0},
       {"nanosecond", 1, 1000000000},
       {"nanoseconds", 1, 1000000000},
       {"hr", 3600, 1},
       {"", 0, 0},
       {"week", 604800, 1},
       {"weeks", 604800, 1},
       {"millisecond", 1, 1000},
       {"milliseconds", 1, 1000},
       {"", 0, 0},
       {"", 0, 0},
       {"", 0, 0},
       {"", 0, 0},
       {"", 0, 0},
       {"", 0, 0},
       {"year", 31556952, 1},
       {"years", 31556952, 1},
       {"", 0, 0},
       {"", 0, 0},
       {"", 0, 0},
       {"", 0, 0},
       {"", 0, 0},
       {"", 0, 0},
       {"", 0, 0},
       {"", 0, 0},
       {"", 0, 0},
       {"", 0, 0},
       {"", 0, 0},
       {"", 0, 0},
       {"day", 86400, 1},
       {"days", 86400, 1}}};

  if (str.size() <= MAX_WORD_LENGTH && str.size() >= MIN_WORD_LENGTH) {
    unsigned int key = hash(str);
    if (key <= MAX_HASH_VALUE) {
      if (wordlist[key].name == str) {
        return &wordlist[key];
      }
    }
  }
  return nullptr;
}

} // unnamed namespace

namespace facebook::eden {

const ChronoUnit* FOLLY_NULLABLE lookupChronoUnitInfo(StringPiece unitName) {
  return ChronoUnitPerfectHash::in_word_set(unitName);
}

} // namespace facebook::eden