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ClickHouse/src/IO/parseDateTimeBestEffort.cpp

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#include <common/DateLUTImpl.h>
#include <Common/StringUtils/StringUtils.h>
#include <IO/ReadBuffer.h>
#include <IO/ReadHelpers.h>
#include <IO/WriteHelpers.h>
#include <IO/parseDateTimeBestEffort.h>
#include <limits>
namespace DB
{
namespace ErrorCodes
{
extern const int LOGICAL_ERROR;
extern const int CANNOT_PARSE_DATETIME;
}
namespace
{
inline size_t readDigits(char * res, size_t max_chars, ReadBuffer & in)
{
size_t num_chars = 0;
while (!in.eof() && isNumericASCII(*in.position()) && num_chars < max_chars)
{
res[num_chars] = *in.position() - '0';
++num_chars;
++in.position();
}
return num_chars;
}
inline size_t readAlpha(char * res, size_t max_chars, ReadBuffer & in)
{
size_t num_chars = 0;
while (!in.eof() && isAlphaASCII(*in.position()) && num_chars < max_chars)
{
res[num_chars] = *in.position();
++num_chars;
++in.position();
}
return num_chars;
}
#if defined(__PPC__)
#if !__clang__
#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
#endif
#endif
template <size_t digit, size_t power_of_ten, typename T>
inline void readDecimalNumberImpl(T & res, const char * src)
{
res += src[digit] * power_of_ten;
if constexpr (digit > 0)
readDecimalNumberImpl<digit - 1, power_of_ten * 10>(res, src);
}
template <size_t num_digits, typename T>
inline void readDecimalNumber(T & res, const char * src)
{
readDecimalNumberImpl<num_digits - 1, 1>(res, src);
}
template <typename T>
inline void readDecimalNumber(T & res, size_t num_digits, const char * src)
{
#define READ_DECIMAL_NUMBER(N) do { res *= common::exp10_i32(N); readDecimalNumber<N>(res, src); src += (N); num_digits -= (N); } while (false)
while (num_digits)
{
switch (num_digits)
{
case 3: READ_DECIMAL_NUMBER(3); break;
case 2: READ_DECIMAL_NUMBER(2); break;
case 1: READ_DECIMAL_NUMBER(1); break;
default: READ_DECIMAL_NUMBER(4); break;
}
}
#undef READ_DECIMAL_NUMBER
}
struct DateTimeSubsecondPart
{
Int64 value;
UInt8 digits;
};
template <typename ReturnType>
ReturnType parseDateTimeBestEffortImpl(
time_t & res,
ReadBuffer & in,
const DateLUTImpl & local_time_zone,
const DateLUTImpl & utc_time_zone,
DateTimeSubsecondPart * fractional)
{
auto on_error = [](const std::string & message [[maybe_unused]], int code [[maybe_unused]])
{
if constexpr (std::is_same_v<ReturnType, void>)
throw Exception(message, code);
else
return false;
};
UInt16 year = 0;
UInt8 month = 0;
UInt8 day_of_month = 0;
UInt8 hour = 0;
UInt8 minute = 0;
UInt8 second = 0;
bool has_time = false;
bool has_time_zone_offset = false;
bool time_zone_offset_negative = false;
UInt8 time_zone_offset_hour = 0;
UInt8 time_zone_offset_minute = 0;
bool is_pm = false;
auto read_alpha_month = [&month] (const auto & alpha)
{
if (0 == strncasecmp(alpha, "Jan", 3)) month = 1;
else if (0 == strncasecmp(alpha, "Feb", 3)) month = 2;
else if (0 == strncasecmp(alpha, "Mar", 3)) month = 3;
else if (0 == strncasecmp(alpha, "Apr", 3)) month = 4;
else if (0 == strncasecmp(alpha, "May", 3)) month = 5;
else if (0 == strncasecmp(alpha, "Jun", 3)) month = 6;
else if (0 == strncasecmp(alpha, "Jul", 3)) month = 7;
else if (0 == strncasecmp(alpha, "Aug", 3)) month = 8;
else if (0 == strncasecmp(alpha, "Sep", 3)) month = 9;
else if (0 == strncasecmp(alpha, "Oct", 3)) month = 10;
else if (0 == strncasecmp(alpha, "Nov", 3)) month = 11;
else if (0 == strncasecmp(alpha, "Dec", 3)) month = 12;
else
return false;
return true;
};
while (!in.eof())
{
char digits[std::numeric_limits<UInt64>::digits10];
size_t num_digits = 0;
if (!year || !has_time)
{
num_digits = readDigits(digits, sizeof(digits), in);
if (num_digits == 10 && !year && !has_time)
{
/// This is unix timestamp.
readDecimalNumber<10>(res, digits);
return ReturnType(true);
}
else if (num_digits == 9 && !year && !has_time)
{
/// This is unix timestamp.
readDecimalNumber<9>(res, digits);
return ReturnType(true);
}
else if (num_digits == 14 && !year && !has_time)
{
/// This is YYYYMMDDhhmmss
readDecimalNumber<4>(year, digits);
readDecimalNumber<2>(month, digits + 4);
readDecimalNumber<2>(day_of_month, digits + 6);
readDecimalNumber<2>(hour, digits + 8);
readDecimalNumber<2>(minute, digits + 10);
readDecimalNumber<2>(second, digits + 12);
has_time = true;
}
else if (num_digits == 8 && !year)
{
/// This is YYYYMMDD
readDecimalNumber<4>(year, digits);
readDecimalNumber<2>(month, digits + 4);
readDecimalNumber<2>(day_of_month, digits + 6);
}
else if (num_digits == 6)
{
/// This is YYYYMM
if (!year && !month)
{
readDecimalNumber<4>(year, digits);
readDecimalNumber<2>(month, digits + 4);
}
else if (!has_time)
{
readDecimalNumber<2>(hour, digits);
readDecimalNumber<2>(minute, digits + 2);
readDecimalNumber<2>(second, digits + 4);
has_time = true;
}
else
return on_error("Cannot read DateTime: ambiguous 6 digits, it can be YYYYMM or hhmmss", ErrorCodes::CANNOT_PARSE_DATETIME);
}
else if (num_digits == 4 && !year)
{
/// YYYY
/// YYYY*MM
/// YYYY*MM*DD
/// YYYY*M
/// YYYY*M*DD
/// YYYY*M*D
readDecimalNumber<4>(year, digits);
if (!in.eof())
{
char delimiter_after_year = *in.position();
if (delimiter_after_year < 0x20
|| delimiter_after_year == ','
|| delimiter_after_year == ';'
|| delimiter_after_year == '\''
|| delimiter_after_year == '"')
break;
if (month)
continue;
++in.position();
num_digits = readDigits(digits, sizeof(digits), in);
if (num_digits == 2)
readDecimalNumber<2>(month, digits);
else if (num_digits == 1)
readDecimalNumber<1>(month, digits);
else if (delimiter_after_year == ' ')
continue;
else
return on_error("Cannot read DateTime: unexpected number of decimal digits after year: " + toString(num_digits), ErrorCodes::CANNOT_PARSE_DATETIME);
/// Only the same delimiter.
if (!day_of_month && checkChar(delimiter_after_year, in))
{
num_digits = readDigits(digits, sizeof(digits), in);
if (num_digits == 2)
readDecimalNumber<2>(day_of_month, digits);
else if (num_digits == 1)
readDecimalNumber<1>(day_of_month, digits);
else if (delimiter_after_year == ' ')
continue;
else
return on_error("Cannot read DateTime: unexpected number of decimal digits after year and month: " + toString(num_digits), ErrorCodes::CANNOT_PARSE_DATETIME);
}
}
}
else if (num_digits == 2 || num_digits == 1)
{
/// hh:mm:ss
/// hh:mm
/// hh - only if already have day of month
/// DD/MM/YYYY
/// DD/MM/YY
/// DD.MM.YYYY
/// DD.MM.YY
/// DD-MM-YYYY
/// DD-MM-YY
/// DD
UInt8 hour_or_day_of_month = 0;
if (num_digits == 2)
readDecimalNumber<2>(hour_or_day_of_month, digits);
else if (num_digits == 1) //-V547
readDecimalNumber<1>(hour_or_day_of_month, digits);
else
return on_error("Cannot read DateTime: logical error, unexpected branch in code", ErrorCodes::LOGICAL_ERROR);
if (checkChar(':', in))
{
if (has_time)
return on_error("Cannot read DateTime: time component is duplicated", ErrorCodes::CANNOT_PARSE_DATETIME);
hour = hour_or_day_of_month;
has_time = true;
num_digits = readDigits(digits, sizeof(digits), in);
if (num_digits == 2)
readDecimalNumber<2>(minute, digits);
else if (num_digits == 1)
readDecimalNumber<1>(minute, digits);
else
return on_error("Cannot read DateTime: unexpected number of decimal digits after hour: " + toString(num_digits), ErrorCodes::CANNOT_PARSE_DATETIME);
if (checkChar(':', in))
{
num_digits = readDigits(digits, sizeof(digits), in);
if (num_digits == 2)
readDecimalNumber<2>(second, digits);
else if (num_digits == 1)
readDecimalNumber<1>(second, digits);
else
return on_error("Cannot read DateTime: unexpected number of decimal digits after hour and minute: " + toString(num_digits), ErrorCodes::CANNOT_PARSE_DATETIME);
}
}
else if (checkChar('/', in) || checkChar('.', in) || checkChar('-', in))
{
if (day_of_month)
return on_error("Cannot read DateTime: day of month is duplicated", ErrorCodes::CANNOT_PARSE_DATETIME);
if (month)
return on_error("Cannot read DateTime: month is duplicated", ErrorCodes::CANNOT_PARSE_DATETIME);
day_of_month = hour_or_day_of_month;
num_digits = readDigits(digits, sizeof(digits), in);
if (num_digits == 2)
readDecimalNumber<2>(month, digits);
else if (num_digits == 1)
readDecimalNumber<1>(month, digits);
else if (num_digits == 0)
{
/// Month in alphabetical form
char alpha[9]; /// The longest month name: September
size_t num_alpha = readAlpha(alpha, sizeof(alpha), in);
if (num_alpha < 3)
return on_error("Cannot read DateTime: unexpected number of alphabetical characters after day of month: " + toString(num_alpha), ErrorCodes::CANNOT_PARSE_DATETIME);
if (!read_alpha_month(alpha))
return on_error("Cannot read DateTime: alphabetical characters after day of month don't look like month: " + std::string(alpha, 3), ErrorCodes::CANNOT_PARSE_DATETIME);
}
else
return on_error("Cannot read DateTime: unexpected number of decimal digits after day of month: " + toString(num_digits), ErrorCodes::CANNOT_PARSE_DATETIME);
if (checkChar('/', in) || checkChar('.', in) || checkChar('-', in))
{
if (year)
return on_error("Cannot read DateTime: year component is duplicated", ErrorCodes::CANNOT_PARSE_DATETIME);
num_digits = readDigits(digits, sizeof(digits), in);
if (num_digits == 4)
readDecimalNumber<4>(year, digits);
else if (num_digits == 2)
{
readDecimalNumber<2>(year, digits);
if (year >= 70)
year += 1900;
else
year += 2000;
}
else
return on_error("Cannot read DateTime: unexpected number of decimal digits after day of month and month: " + toString(num_digits), ErrorCodes::CANNOT_PARSE_DATETIME);
}
}
else
{
if (day_of_month)
hour = hour_or_day_of_month;
else
day_of_month = hour_or_day_of_month;
}
}
else if (num_digits != 0)
return on_error("Cannot read DateTime: unexpected number of decimal digits: " + toString(num_digits), ErrorCodes::CANNOT_PARSE_DATETIME);
}
if (num_digits == 0)
{
char c = *in.position();
/// 'T' is a separator between date and time according to ISO 8601.
/// But don't skip it if we didn't read the date part yet, because 'T' is also a prefix or 'Tue' and 'Thu'.
if (c == ' ' || (c == 'T' && year && !has_time))
{
++in.position();
}
else if (c == 'Z')
{
++in.position();
has_time_zone_offset = true;
}
else if (c == '.') /// We don't support comma (ISO 8601:2004) for fractional part of second to not mess up with CSV separator.
{
if (!has_time)
return on_error("Cannot read DateTime: unexpected point symbol", ErrorCodes::CANNOT_PARSE_DATETIME);
++in.position();
num_digits = readDigits(digits, sizeof(digits), in);
if (fractional)
{
using FractionalType = typename std::decay<decltype(fractional->value)>::type;
// Reading more decimal digits than fits into FractionalType would case an
// overflow, so it is better to skip all digits from the right side that do not
// fit into result type. To provide less precise value rather than bogus one.
num_digits = std::min(static_cast<size_t>(std::numeric_limits<FractionalType>::digits10), num_digits);
fractional->digits = num_digits;
readDecimalNumber(fractional->value, num_digits, digits);
}
}
else if (c == '+' || c == '-')
{
++in.position();
has_time_zone_offset = true;
if (c == '-')
time_zone_offset_negative = true;
num_digits = readDigits(digits, sizeof(digits), in);
if (num_digits == 4)
{
readDecimalNumber<2>(time_zone_offset_hour, digits);
readDecimalNumber<2>(time_zone_offset_minute, digits + 2);
}
else if (num_digits == 3)
{
readDecimalNumber<1>(time_zone_offset_hour, digits);
readDecimalNumber<2>(time_zone_offset_minute, digits + 1);
}
else if (num_digits == 2)
{
readDecimalNumber<2>(time_zone_offset_hour, digits);
}
else if (num_digits == 1)
{
readDecimalNumber<1>(time_zone_offset_hour, digits);
}
else
return on_error("Cannot read DateTime: unexpected number of decimal digits for time zone offset: " + toString(num_digits), ErrorCodes::CANNOT_PARSE_DATETIME);
if (num_digits < 3 && checkChar(':', in))
{
num_digits = readDigits(digits, sizeof(digits), in);
if (num_digits == 2)
{
readDecimalNumber<2>(time_zone_offset_minute, digits);
}
else if (num_digits == 1)
{
readDecimalNumber<1>(time_zone_offset_minute, digits);
}
else
return on_error("Cannot read DateTime: unexpected number of decimal digits for time zone offset in minutes: " + toString(num_digits), ErrorCodes::CANNOT_PARSE_DATETIME);
}
}
else
{
char alpha[3];
size_t num_alpha = readAlpha(alpha, sizeof(alpha), in);
if (!num_alpha)
{
break;
}
else if (num_alpha == 1)
{
return on_error("Cannot read DateTime: unexpected alphabetical character", ErrorCodes::CANNOT_PARSE_DATETIME);
}
else if (num_alpha == 2)
{
if (alpha[1] == 'M' || alpha[1] == 'm')
{
if (alpha[0] == 'A' || alpha[0] == 'a')
{
}
else if (alpha[0] == 'P' || alpha[0] == 'p')
{
is_pm = true;
}
else
return on_error("Cannot read DateTime: unexpected word", ErrorCodes::CANNOT_PARSE_DATETIME);
}
else
return on_error("Cannot read DateTime: unexpected word", ErrorCodes::CANNOT_PARSE_DATETIME);
}
else if (num_alpha == 3)
{
bool has_day_of_week = false;
if (read_alpha_month(alpha))
{
}
else if (0 == strncasecmp(alpha, "UTC", 3)) has_time_zone_offset = true; // NOLINT
else if (0 == strncasecmp(alpha, "GMT", 3)) has_time_zone_offset = true;
else if (0 == strncasecmp(alpha, "MSK", 3)) { has_time_zone_offset = true; time_zone_offset_hour = 3; }
else if (0 == strncasecmp(alpha, "MSD", 3)) { has_time_zone_offset = true; time_zone_offset_hour = 4; }
else if (0 == strncasecmp(alpha, "Mon", 3)) has_day_of_week = true; // NOLINT
else if (0 == strncasecmp(alpha, "Tue", 3)) has_day_of_week = true;
else if (0 == strncasecmp(alpha, "Wed", 3)) has_day_of_week = true;
else if (0 == strncasecmp(alpha, "Thu", 3)) has_day_of_week = true;
else if (0 == strncasecmp(alpha, "Fri", 3)) has_day_of_week = true;
else if (0 == strncasecmp(alpha, "Sat", 3)) has_day_of_week = true;
else if (0 == strncasecmp(alpha, "Sun", 3)) has_day_of_week = true;
else
return on_error("Cannot read DateTime: unexpected word", ErrorCodes::CANNOT_PARSE_DATETIME);
while (!in.eof() && isAlphaASCII(*in.position()))
++in.position();
/// For RFC 2822
if (has_day_of_week)
checkChar(',', in);
}
else
return on_error("Cannot read DateTime: logical error, unexpected branch in code", ErrorCodes::LOGICAL_ERROR);
}
}
}
if (!year)
year = 2000;
if (!month)
month = 1;
if (!day_of_month)
day_of_month = 1;
if (is_pm && hour < 12)
hour += 12;
auto adjust_time_zone = [&]
{
if (time_zone_offset_hour)
{
if (time_zone_offset_negative)
res += time_zone_offset_hour * 3600;
else
res -= time_zone_offset_hour * 3600;
}
if (time_zone_offset_minute)
{
if (time_zone_offset_negative)
res += time_zone_offset_minute * 60;
else
res -= time_zone_offset_minute * 60;
}
};
if (has_time_zone_offset)
{
res = utc_time_zone.makeDateTime(year, month, day_of_month, hour, minute, second);
adjust_time_zone();
}
else
{
res = local_time_zone.makeDateTime(year, month, day_of_month, hour, minute, second);
}
return ReturnType(true);
}
template <typename ReturnType>
ReturnType parseDateTime64BestEffortImpl(DateTime64 & res, UInt32 scale, ReadBuffer & in, const DateLUTImpl & local_time_zone, const DateLUTImpl & utc_time_zone)
{
time_t whole;
DateTimeSubsecondPart subsecond = {0, 0}; // needs to be explicitly initialized sine it could be missing from input string
if (!parseDateTimeBestEffortImpl<bool>(whole, in, local_time_zone, utc_time_zone, &subsecond))
return ReturnType(false);
DateTime64::NativeType fractional = subsecond.value;
if (scale < subsecond.digits)
{
fractional /= common::exp10_i64(subsecond.digits - scale);
}
else if (scale > subsecond.digits)
{
fractional *= common::exp10_i64(scale - subsecond.digits);
}
res = DecimalUtils::decimalFromComponents<DateTime64>(whole, fractional, scale);
return ReturnType(true);
}
}
#if defined(__PPC__)
#if !__clang__
#pragma GCC diagnostic pop
#endif
#endif
void parseDateTimeBestEffort(time_t & res, ReadBuffer & in, const DateLUTImpl & local_time_zone, const DateLUTImpl & utc_time_zone)
{
parseDateTimeBestEffortImpl<void>(res, in, local_time_zone, utc_time_zone, nullptr);
}
bool tryParseDateTimeBestEffort(time_t & res, ReadBuffer & in, const DateLUTImpl & local_time_zone, const DateLUTImpl & utc_time_zone)
{
return parseDateTimeBestEffortImpl<bool>(res, in, local_time_zone, utc_time_zone, nullptr);
}
void parseDateTime64BestEffort(DateTime64 & res, UInt32 scale, ReadBuffer & in, const DateLUTImpl & local_time_zone, const DateLUTImpl & utc_time_zone)
{
return parseDateTime64BestEffortImpl<void>(res, scale, in, local_time_zone, utc_time_zone);
}
bool tryParseDateTime64BestEffort(DateTime64 & res, UInt32 scale, ReadBuffer & in, const DateLUTImpl & local_time_zone, const DateLUTImpl & utc_time_zone)
{
return parseDateTime64BestEffortImpl<bool>(res, scale, in, local_time_zone, utc_time_zone);
}
}
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