src/date/dateparser.cc

// Copyright 2011 the V8 project 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 "src/date/dateparser.h"

#include "src/objects/objects-inl.h"
#include "src/strings/char-predicates-inl.h"

namespace v8 {
namespace internal {

bool DateParser::DayComposer::Write(double* output) {
  if (index_ < 1) return false;
  // Day and month defaults to 1.
  while (index_ < kSize) {
    comp_[index_++] = 1;
  }

  int year = 0;  // Default year is 0 (=> 2000) for KJS compatibility.
  int month = kNone;
  int day = kNone;

  if (named_month_ == kNone) {
    if (is_iso_date_ || (index_ == 3 && !IsDay(comp_[0]))) {
      // YMD
      year = comp_[0];
      month = comp_[1];
      day = comp_[2];
    } else {
      // MD(Y)
      month = comp_[0];
      day = comp_[1];
      if (index_ == 3) year = comp_[2];
    }
  } else {
    month = named_month_;
    if (index_ == 1) {
      // MD or DM
      day = comp_[0];
    } else if (!IsDay(comp_[0])) {
      // YMD, MYD, or YDM
      year = comp_[0];
      day = comp_[1];
    } else {
      // DMY, MDY, or DYM
      day = comp_[0];
      year = comp_[1];
    }
  }

  if (!is_iso_date_) {
    if (Between(year, 0, 49))
      year += 2000;
    else if (Between(year, 50, 99))
      year += 1900;
  }

  if (!Smi::IsValid(year) || !IsMonth(month) || !IsDay(day)) return false;

  output[YEAR] = year;
  output[MONTH] = month - 1;  // 0-based
  output[DAY] = day;
  return true;
}

bool DateParser::TimeComposer::Write(double* output) {
  // All time slots default to 0
  while (index_ < kSize) {
    comp_[index_++] = 0;
  }

  int& hour = comp_[0];
  int& minute = comp_[1];
  int& second = comp_[2];
  int& millisecond = comp_[3];

  if (hour_offset_ != kNone) {
    if (!IsHour12(hour)) return false;
    hour %= 12;
    hour += hour_offset_;
  }

  if (!IsHour(hour) || !IsMinute(minute) || !IsSecond(second) ||
      !IsMillisecond(millisecond)) {
    // A 24th hour is allowed if minutes, seconds, and milliseconds are 0
    if (hour != 24 || minute != 0 || second != 0 || millisecond != 0) {
      return false;
    }
  }

  output[HOUR] = hour;
  output[MINUTE] = minute;
  output[SECOND] = second;
  output[MILLISECOND] = millisecond;
  return true;
}

bool DateParser::TimeZoneComposer::Write(double* output) {
  if (sign_ != kNone) {
    if (hour_ == kNone) hour_ = 0;
    if (minute_ == kNone) minute_ = 0;
    // Avoid signed integer overflow (undefined behavior) by doing unsigned
    // arithmetic.
    unsigned total_seconds_unsigned = hour_ * 3600U + minute_ * 60U;
    if (total_seconds_unsigned > Smi::kMaxValue) return false;
    int total_seconds = static_cast<int>(total_seconds_unsigned);
    if (sign_ < 0) {
      total_seconds = -total_seconds;
    }
    DCHECK(Smi::IsValid(total_seconds));
    output[UTC_OFFSET] = total_seconds;
  } else {
    output[UTC_OFFSET] = std::numeric_limits<double>::quiet_NaN();
  }
  return true;
}

const int8_t
    DateParser::KeywordTable::array[][DateParser::KeywordTable::kEntrySize] = {
        {'j', 'a', 'n', DateParser::MONTH_NAME, 1},
        {'f', 'e', 'b', DateParser::MONTH_NAME, 2},
        {'m', 'a', 'r', DateParser::MONTH_NAME, 3},
        {'a', 'p', 'r', DateParser::MONTH_NAME, 4},
        {'m', 'a', 'y', DateParser::MONTH_NAME, 5},
        {'j', 'u', 'n', DateParser::MONTH_NAME, 6},
        {'j', 'u', 'l', DateParser::MONTH_NAME, 7},
        {'a', 'u', 'g', DateParser::MONTH_NAME, 8},
        {'s', 'e', 'p', DateParser::MONTH_NAME, 9},
        {'o', 'c', 't', DateParser::MONTH_NAME, 10},
        {'n', 'o', 'v', DateParser::MONTH_NAME, 11},
        {'d', 'e', 'c', DateParser::MONTH_NAME, 12},
        {'a', 'm', '\0', DateParser::AM_PM, 0},
        {'p', 'm', '\0', DateParser::AM_PM, 12},
        {'u', 't', '\0', DateParser::TIME_ZONE_NAME, 0},
        {'u', 't', 'c', DateParser::TIME_ZONE_NAME, 0},
        {'z', '\0', '\0', DateParser::TIME_ZONE_NAME, 0},
        {'g', 'm', 't', DateParser::TIME_ZONE_NAME, 0},
        {'c', 'd', 't', DateParser::TIME_ZONE_NAME, -5},
        {'c', 's', 't', DateParser::TIME_ZONE_NAME, -6},
        {'e', 'd', 't', DateParser::TIME_ZONE_NAME, -4},
        {'e', 's', 't', DateParser::TIME_ZONE_NAME, -5},
        {'m', 'd', 't', DateParser::TIME_ZONE_NAME, -6},
        {'m', 's', 't', DateParser::TIME_ZONE_NAME, -7},
        {'p', 'd', 't', DateParser::TIME_ZONE_NAME, -7},
        {'p', 's', 't', DateParser::TIME_ZONE_NAME, -8},
        {'t', '\0', '\0', DateParser::TIME_SEPARATOR, 0},
        {'\0', '\0', '\0', DateParser::INVALID, 0},
};

// We could use perfect hashing here, but this is not a bottleneck.
int DateParser::KeywordTable::Lookup(const uint32_t* pre, int len) {
  int i;
  for (i = 0; array[i][kTypeOffset] != INVALID; i++) {
    int j = 0;
    while (j < kPrefixLength && pre[j] == static_cast<uint32_t>(array[i][j])) {
      j++;
    }
    // Check if we have a match and the length is legal.
    // Word longer than keyword is only allowed for month names.
    if (j == kPrefixLength &&
        (len <= kPrefixLength || array[i][kTypeOffset] == MONTH_NAME)) {
      return i;
    }
  }
  return i;
}

int DateParser::ReadMilliseconds(DateToken token) {
  // Read first three significant digits of the original numeral,
  // as inferred from the value and the number of digits.
  // I.e., use the number of digits to see if there were
  // leading zeros.
  int number = token.number();
  int length = token.length();
  if (length < 3) {
    // Less than three digits. Multiply to put most significant digit
    // in hundreds position.
    if (length == 1) {
      number *= 100;
    } else if (length == 2) {
      number *= 10;
    }
  } else if (length > 3) {
    if (length > kMaxSignificantDigits) length = kMaxSignificantDigits;
    // More than three digits. Divide by 10^(length - 3) to get three
    // most significant digits.
    int factor = 1;
    do {
      DCHECK_LE(factor, 100000000);  // factor won't overflow.
      factor *= 10;
      length--;
    } while (length > 3);
    number /= factor;
  }
  return number;
}

}  // namespace internal
}  // namespace v8