/// <summary>
/// Convert a datetime from the universal time scale stored as a
/// <c>BigDecimal</c> to a <c>long</c> in the given time scale.
/// Since this calculation requires a divide, we must round. The straight
/// forward way to round by adding half of the divisor will push the sum out
/// of range for values within have the divisor of the limits of the
/// precision of a <c>long</c>. To get around this, we do the rounding
/// like this:
/// <p>
/// <code>
/// (universalTime - units + units/2) / units + 1
/// </code>
/// <p>
/// (i.e. we subtract units first to guarantee that we'll still be in range
/// when we add <code>units/2</code>. We then need to add one to the quotent
/// to make up for the extra subtraction. This simplifies to:
/// <p>
/// <code>
/// (universalTime - units/2) / units - 1
/// </code>
/// <p>
/// For negative values to round away from zero, we need to flip the signs:
/// <p>
/// <code>
/// (universalTime + units/2) / units + 1
/// </code>
/// <p>
/// Since we also need to subtract the epochOffset, we fold the
/// <code>+/- 1</code> into the offset value. (i.e.
/// <c>epochOffsetP1</c>, <c>epochOffsetM1</c>.)
/// </summary>
///
/// <param name="universalTime">The datetime in the universal time scale</param>
/// <param name="timeScale">The time scale to convert to</param>
/// <returns>The datetime converted to the given time scale</returns>
/// @stable ICU 3.2
public static long ToLong(long universalTime, int timeScale)
{
UniversalTimeScale.TimeScaleData data = ToRangeCheck(universalTime, timeScale);
if (universalTime < 0)
{
if (universalTime < data.minRound)
{
return((universalTime + data.unitsRound) / data.units
- data.epochOffsetP1);
}
return((universalTime - data.unitsRound) / data.units
- data.epochOffset);
}
if (universalTime > data.maxRound)
{
return((universalTime - data.unitsRound) / data.units
- data.epochOffsetM1);
}
return((universalTime + data.unitsRound) / data.units
- data.epochOffset);
}
/// <summary>
/// Convert a <c>BigDecimal</c> datetime from the given time scale to
/// the universal time scale. All calculations are done using
/// <c>BigDecimal</c> to guarantee that the value does not go out of
/// range.
/// </summary>
///
/// <param name="otherTime">The <c>BigDecimal</c> datetime</param>
/// <param name="timeScale">The time scale to convert from</param>
/// <returns>The datetime converted to the universal time scale</returns>
/// @stable ICU 3.2
public static BigDecimal BigDecimalFrom(BigDecimal otherTime, int timeScale)
{
UniversalTimeScale.TimeScaleData data = GetTimeScaleData(timeScale);
BigDecimal units_0 = new BigDecimal(data.units);
BigDecimal epochOffset_1 = new BigDecimal(data.epochOffset);
return(otherTime.Add(epochOffset_1).Multiply(units_0));
}
/// <exclude/>
/// <summary>
/// Convert a time in the Universal Time Scale into another time scale. The
/// division used to do the conversion rounds down.
/// NOTE: This is an internal routine used by the tool that generates the to
/// and from limits. Use it at your own risk.
/// </summary>
///
/// <param name="universalTime">the time in the Universal Time scale</param>
/// <param name="timeScale">the time scale to convert to</param>
/// <returns>the time in the given time scale</returns>
public static BigDecimal ToBigDecimalTrunc(BigDecimal universalTime,
int timeScale)
{
UniversalTimeScale.TimeScaleData data = GetTimeScaleData(timeScale);
BigDecimal units_0 = new BigDecimal(data.units);
BigDecimal epochOffset_1 = new BigDecimal(data.epochOffset);
return(universalTime.Divide(units_0, IBM.ICU.Math.BigDecimal.ROUND_DOWN).Subtract(
epochOffset_1));
}
private static UniversalTimeScale.TimeScaleData FromRangeCheck(long otherTime, int scale)
{
UniversalTimeScale.TimeScaleData data = GetTimeScaleData(scale);
if (otherTime >= data.fromMin && otherTime <= data.fromMax)
{
return(data);
}
throw new ArgumentException("otherTime out of range:"
+ otherTime);
}
private static UniversalTimeScale.TimeScaleData ToRangeCheck(long universalTime, int scale)
{
UniversalTimeScale.TimeScaleData data = GetTimeScaleData(scale);
if (universalTime >= data.toMin && universalTime <= data.toMax)
{
return(data);
}
throw new ArgumentException("universalTime out of range:"
+ universalTime);
}
/// <summary>
/// Get a value associated with a particular time scale.
/// </summary>
///
/// <param name="scale">- the time scale</param>
/// <param name="value">- a constant representing the value to get</param>
/// <returns>- the value.</returns>
/// @stable ICU 3.2
public static long GetTimeScaleValue(int scale, int value_ren)
{
UniversalTimeScale.TimeScaleData data = GetTimeScaleData(scale);
switch (value_ren)
{
case UNITS_VALUE:
return(data.units);
case EPOCH_OFFSET_VALUE:
return(data.epochOffset);
case FROM_MIN_VALUE:
return(data.fromMin);
case FROM_MAX_VALUE:
return(data.fromMax);
case TO_MIN_VALUE:
return(data.toMin);
case TO_MAX_VALUE:
return(data.toMax);
case EPOCH_OFFSET_PLUS_1_VALUE:
return(data.epochOffsetP1);
case EPOCH_OFFSET_MINUS_1_VALUE:
return(data.epochOffsetM1);
case UNITS_ROUND_VALUE:
return(data.unitsRound);
case MIN_ROUND_VALUE:
return(data.minRound);
case MAX_ROUND_VALUE:
return(data.maxRound);
default:
throw new ArgumentException("value out of range: " + value_ren);
}
}
// /CLOVER:ON
/// <summary>
/// Convert a <c>long</c> datetime from the given time scale to the
/// universal time scale.
/// </summary>
///
/// <param name="otherTime">The <c>long</c> datetime</param>
/// <param name="timeScale">The time scale to convert from</param>
/// <returns>The datetime converted to the universal time scale</returns>
/// @stable ICU 3.2
public static long From(long otherTime, int timeScale)
{
UniversalTimeScale.TimeScaleData data = FromRangeCheck(otherTime, timeScale);
return((otherTime + data.epochOffset) * data.units);
}
