Move ICU headers from public/{common,i18n} to source/{common,i18n}

public/i18n/unicode/utmscale.h

-/*
-*******************************************************************************
-* Copyright (C) 2004 - 2008, International Business Machines Corporation and
-* others. All Rights Reserved.
-*******************************************************************************
-*/
-
-#ifndef UTMSCALE_H
-#define UTMSCALE_H
-
-#include "unicode/utypes.h"
-
-#if !UCONFIG_NO_FORMATTING
-
-/** 
- * \file
- * \brief C API: Universal Time Scale
- *
- * There are quite a few different conventions for binary datetime, depending on different
- * platforms and protocols. Some of these have severe drawbacks. For example, people using
- * Unix time (seconds since Jan 1, 1970) think that they are safe until near the year 2038.
- * But cases can and do arise where arithmetic manipulations causes serious problems. Consider
- * the computation of the average of two datetimes, for example: if one calculates them with
- * <code>averageTime = (time1 + time2)/2</code>, there will be overflow even with dates
- * around the present. Moreover, even if these problems don't occur, there is the issue of
- * conversion back and forth between different systems.
- *
- * <p>
- * Binary datetimes differ in a number of ways: the datatype, the unit,
- * and the epoch (origin). We'll refer to these as time scales. For example:
- *
- * <table border="1" cellspacing="0" cellpadding="4">
- *  <caption>Table 1: Binary Time Scales</caption>
- *  <tr>
- *    <th align="left">Source</th>
- *    <th align="left">Datatype</th>
- *    <th align="left">Unit</th>
- *    <th align="left">Epoch</th>
- *  </tr>
- *
- *  <tr>
- *    <td>UDTS_JAVA_TIME</td>
- *    <td>int64_t</td>
- *    <td>milliseconds</td>
- *    <td>Jan 1, 1970</td>
- *  </tr>
- *  <tr>
- *
- *    <td>UDTS_UNIX_TIME</td>
- *    <td>int32_t or int64_t</td>
- *    <td>seconds</td>
- *    <td>Jan 1, 1970</td>
- *  </tr>
- *  <tr>
- *    <td>UDTS_ICU4C_TIME</td>
- *
- *    <td>double</td>
- *    <td>milliseconds</td>
- *    <td>Jan 1, 1970</td>
- *  </tr>
- *  <tr>
- *    <td>UDTS_WINDOWS_FILE_TIME</td>
- *    <td>int64_t</td>
- *
- *    <td>ticks (100 nanoseconds)</td>
- *    <td>Jan 1, 1601</td>
- *  </tr>
- *  <tr>
- *    <td>UDTS_DOTNET_DATE_TIME</td>
- *    <td>int64_t</td>
- *    <td>ticks (100 nanoseconds)</td>
- *
- *    <td>Jan 1, 0001</td>
- *  </tr>
- *  <tr>
- *    <td>UDTS_MAC_OLD_TIME</td>
- *    <td>int32_t or int64_t</td>
- *    <td>seconds</td>
- *    <td>Jan 1, 1904</td>
- *
- *  </tr>
- *  <tr>
- *    <td>UDTS_MAC_TIME</td>
- *    <td>double</td>
- *    <td>seconds</td>
- *    <td>Jan 1, 2001</td>
- *  </tr>
- *
- *  <tr>
- *    <td>UDTS_EXCEL_TIME</td>
- *    <td>?</td>
- *    <td>days</td>
- *    <td>Dec 31, 1899</td>
- *  </tr>
- *  <tr>
- *
- *    <td>UDTS_DB2_TIME</td>
- *    <td>?</td>
- *    <td>days</td>
- *    <td>Dec 31, 1899</td>
- *  </tr>
- *
- *  <tr>
- *    <td>UDTS_UNIX_MICROSECONDS_TIME</td>
- *    <td>int64_t</td>
- *    <td>microseconds</td>
- *    <td>Jan 1, 1970</td>
- *  </tr>
- * </table>
- *
- * <p>
- * All of the epochs start at 00:00 am (the earliest possible time on the day in question),
- * and are assumed to be UTC.
- *
- * <p>
- * The ranges for different datatypes are given in the following table (all values in years).
- * The range of years includes the entire range expressible with positive and negative
- * values of the datatype. The range of years for double is the range that would be allowed
- * without losing precision to the corresponding unit.
- *
- * <table border="1" cellspacing="0" cellpadding="4">
- *  <tr>
- *    <th align="left">Units</th>
- *    <th align="left">int64_t</th>
- *    <th align="left">double</th>
- *    <th align="left">int32_t</th>
- *  </tr>
- *
- *  <tr>
- *    <td>1 sec</td>
- *    <td align="right">5.84542x10<sup>11</sup></td>
- *    <td align="right">285,420,920.94</td>
- *    <td align="right">136.10</td>
- *  </tr>
- *  <tr>
- *
- *    <td>1 millisecond</td>
- *    <td align="right">584,542,046.09</td>
- *    <td align="right">285,420.92</td>
- *    <td align="right">0.14</td>
- *  </tr>
- *  <tr>
- *    <td>1 microsecond</td>
- *
- *    <td align="right">584,542.05</td>
- *    <td align="right">285.42</td>
- *    <td align="right">0.00</td>
- *  </tr>
- *  <tr>
- *    <td>100 nanoseconds (tick)</td>
- *    <td align="right">58,454.20</td>
- *    <td align="right">28.54</td>
- *    <td align="right">0.00</td>
- *  </tr>
- *  <tr>
- *    <td>1 nanosecond</td>
- *    <td align="right">584.5420461</td>
- *    <td align="right">0.2854</td>
- *    <td align="right">0.00</td>
- *  </tr>
- * </table>
- *
- * <p>
- * These functions implement a universal time scale which can be used as a 'pivot',
- * and provide conversion functions to and from all other major time scales.
- * This datetimes to be converted to the pivot time, safely manipulated,
- * and converted back to any other datetime time scale.
- *
- *<p>
- * So what to use for this pivot? Java time has plenty of range, but cannot represent
- * .NET <code>System.DateTime</code> values without severe loss of precision. ICU4C time addresses this by using a
- * <code>double</code> that is otherwise equivalent to the Java time. However, there are disadvantages
- * with <code>doubles</code>. They provide for much more graceful degradation in arithmetic operations.
- * But they only have 53 bits of accuracy, which means that they will lose precision when
- * converting back and forth to ticks. What would really be nice would be a
- * <code>long double</code> (80 bits -- 64 bit mantissa), but that is not supported on most systems.
- *
- *<p>
- * The Unix extended time uses a structure with two components: time in seconds and a
- * fractional field (microseconds). However, this is clumsy, slow, and
- * prone to error (you always have to keep track of overflow and underflow in the
- * fractional field). <code>BigDecimal</code> would allow for arbitrary precision and arbitrary range,
- * but we do not want to use this as the normal type, because it is slow and does not
- * have a fixed size.
- *
- *<p>
- * Because of these issues, we ended up concluding that the .NET framework's
- * <code>System.DateTime</code> would be the best pivot. However, we use the full range
- * allowed by the datatype, allowing for datetimes back to 29,000 BC and up to 29,000 AD.
- * This time scale is very fine grained, does not lose precision, and covers a range that
- * will meet almost all requirements. It will not handle the range that Java times do,
- * but frankly, being able to handle dates before 29,000 BC or after 29,000 AD is of very limited interest.
- *
- */
-
-/**
- * <code>UDateTimeScale</code> values are used to specify the time scale used for
- * conversion into or out if the universal time scale.
- *
- * @stable ICU 3.2
- */
-typedef enum UDateTimeScale {
-    /**
-     * Used in the JDK. Data is a Java <code>long</code> (<code>int64_t</code>). Value
-     * is milliseconds since January 1, 1970.
-     *
-     * @stable ICU 3.2
-     */
-    UDTS_JAVA_TIME = 0,
-
-    /**
-     * Used on Unix systems. Data is <code>int32_t</code> or <code>int64_t</code>. Value
-     * is seconds since January 1, 1970.
-     *
-     * @stable ICU 3.2
-     */
-    UDTS_UNIX_TIME,
-    
-    /**
-     * Used in IUC4C. Data is a <code>double</code>. Value
-     * is milliseconds since January 1, 1970.
-     *
-     * @stable ICU 3.2
-     */
-    UDTS_ICU4C_TIME,
-    
-    /**
-     * Used in Windows for file times. Data is an <code>int64_t</code>. Value
-     * is ticks (1 tick == 100 nanoseconds) since January 1, 1601.
-     *
-     * @stable ICU 3.2
-     */
-    UDTS_WINDOWS_FILE_TIME,
-    
-    /**
-     * Used in the .NET framework's <code>System.DateTime</code> structure. Data is an <code>int64_t</code>. Value
-     * is ticks (1 tick == 100 nanoseconds) since January 1, 0001.
-     *
-     * @stable ICU 3.2
-     */
-    UDTS_DOTNET_DATE_TIME,
-    
-    /**
-     * Used in older Macintosh systems. Data is <code>int32_t</code> or <code>int64_t</code>. Value
-     * is seconds since January 1, 1904.
-     *
-     * @stable ICU 3.2
-     */
-    UDTS_MAC_OLD_TIME,
-    
-    /**
-     * Used in newer Macintosh systems. Data is a <code>double</code>. Value
-     * is seconds since January 1, 2001.
-     *
-     * @stable ICU 3.2
-     */
-    UDTS_MAC_TIME,
-    
-    /**
-     * Used in Excel. Data is an <code>?unknown?</code>. Value
-     * is days since December 31, 1899.
-     *
-     * @stable ICU 3.2
-     */
-    UDTS_EXCEL_TIME,
-    
-    /**
-     * Used in DB2. Data is an <code>?unknown?</code>. Value
-     * is days since December 31, 1899.
-     *
-     * @stable ICU 3.2
-     */
-    UDTS_DB2_TIME,
-
-    /**
-     * Data is a <code>long</code>. Value is microseconds since January 1, 1970.
-     * Similar to Unix time (linear value from 1970) and struct timeval
-     * (microseconds resolution).
-     *
-     * @stable ICU 3.8
-     */
-    UDTS_UNIX_MICROSECONDS_TIME,
-
-    /**
-     * The first unused time scale value. The limit of this enum
-     */
-    UDTS_MAX_SCALE
-} UDateTimeScale;
-
-/**
- * <code>UTimeScaleValue</code> values are used to specify the time scale values
- * to <code>utmscale_getTimeScaleValue</code>.
- *
- * @see utmscale_getTimeScaleValue
- *
- * @stable ICU 3.2
- */
-typedef enum UTimeScaleValue {
-    /**
-     * The constant used to select the units vale
-     * for a time scale.
-     * 
-     * @see utmscale_getTimeScaleValue
-     *
-     * @stable ICU 3.2
-     */
-    UTSV_UNITS_VALUE = 0,
-
-    /**
-     * The constant used to select the epoch offset value
-     * for a time scale.
-     * 
-     * @see utmscale_getTimeScaleValue
-     *
-     * @stable ICU 3.2
-     */
-    UTSV_EPOCH_OFFSET_VALUE=1,
-
-    /**
-     * The constant used to select the minimum from value
-     * for a time scale.
-     * 
-     * @see utmscale_getTimeScaleValue
-     *
-     * @stable ICU 3.2
-     */
-    UTSV_FROM_MIN_VALUE=2,
-
-    /**
-     * The constant used to select the maximum from value
-     * for a time scale.
-     * 
-     * @see utmscale_getTimeScaleValue
-     *
-     * @stable ICU 3.2
-     */
-    UTSV_FROM_MAX_VALUE=3,
-
-    /**
-     * The constant used to select the minimum to value
-     * for a time scale.
-     * 
-     * @see utmscale_getTimeScaleValue
-     *
-     * @stable ICU 3.2
-     */
-    UTSV_TO_MIN_VALUE=4,
-
-    /**
-     * The constant used to select the maximum to value
-     * for a time scale.
-     * 
-     * @see utmscale_getTimeScaleValue
-     *
-     * @stable ICU 3.2
-     */
-    UTSV_TO_MAX_VALUE=5,
-
-#ifndef U_HIDE_INTERNAL_API
-    /**
-     * The constant used to select the epoch plus one value
-     * for a time scale.
-     * 
-     * NOTE: This is an internal value. DO NOT USE IT. May not
-     * actually be equal to the epoch offset value plus one.
-     * 
-     * @see utmscale_getTimeScaleValue
-     *
-     * @internal ICU 3.2
-     */
-    UTSV_EPOCH_OFFSET_PLUS_1_VALUE=6,
-
-    /**
-     * The constant used to select the epoch plus one value
-     * for a time scale.
-     * 
-     * NOTE: This is an internal value. DO NOT USE IT. May not
-     * actually be equal to the epoch offset value plus one.
-     * 
-     * @see utmscale_getTimeScaleValue
-     *
-     * @internal ICU 3.2
-     */
-    UTSV_EPOCH_OFFSET_MINUS_1_VALUE=7,
-
-    /**
-     * The constant used to select the units round value
-     * for a time scale.
-     * 
-     * NOTE: This is an internal value. DO NOT USE IT.
-     * 
-     * @see utmscale_getTimeScaleValue
-     *
-     * @internal ICU 3.2
-     */
-    UTSV_UNITS_ROUND_VALUE=8,
-
-    /**
-     * The constant used to select the minimum safe rounding value
-     * for a time scale.
-     * 
-     * NOTE: This is an internal value. DO NOT USE IT.
-     * 
-     * @see utmscale_getTimeScaleValue
-     *
-     * @internal ICU 3.2
-     */
-    UTSV_MIN_ROUND_VALUE=9,
-
-    /**
-     * The constant used to select the maximum safe rounding value
-     * for a time scale.
-     * 
-     * NOTE: This is an internal value. DO NOT USE IT.
-     * 
-     * @see utmscale_getTimeScaleValue
-     *
-     * @internal ICU 3.2
-     */
-    UTSV_MAX_ROUND_VALUE=10,
-
-#endif /* U_HIDE_INTERNAL_API */
-
-    /**
-     * The number of time scale values, in other words limit of this enum.
-     * 
-     * @see utmscale_getTimeScaleValue
-     */
-    UTSV_MAX_SCALE_VALUE=11
-
-} UTimeScaleValue;
-
-/**
- * Get a value associated with a particular time scale.
- * 
- * @param timeScale The time scale
- * @param value A constant representing the value to get
- * @param status The status code. Set to <code>U_ILLEGAL_ARGUMENT_ERROR</code> if arguments are invalid.
- * @return - the value.
- * 
- * @stable ICU 3.2
- */
-U_STABLE int64_t U_EXPORT2
-    utmscale_getTimeScaleValue(UDateTimeScale timeScale, UTimeScaleValue value, UErrorCode *status);
-
-/* Conversion to 'universal time scale' */
-
-/**
- * Convert a <code>int64_t</code> datetime from the given time scale to the universal time scale.
- *
- * @param otherTime The <code>int64_t</code> datetime
- * @param timeScale The time scale to convert from
- * @param status The status code. Set to <code>U_ILLEGAL_ARGUMENT_ERROR</code> if the conversion is out of range.
- * 
- * @return The datetime converted to the universal time scale
- *
- * @stable ICU 3.2
- */
-U_STABLE int64_t U_EXPORT2
-    utmscale_fromInt64(int64_t otherTime, UDateTimeScale timeScale, UErrorCode *status);
-
-/* Conversion from 'universal time scale' */
-
-/**
- * Convert a datetime from the universal time scale to a <code>int64_t</code> in the given time scale.
- *
- * @param universalTime The datetime in the universal time scale
- * @param timeScale The time scale to convert to
- * @param status The status code. Set to <code>U_ILLEGAL_ARGUMENT_ERROR</code> if the conversion is out of range.
- * 
- * @return The datetime converted to the given time scale
- *
- * @stable ICU 3.2
- */
-U_STABLE int64_t U_EXPORT2
-    utmscale_toInt64(int64_t universalTime, UDateTimeScale timeScale, UErrorCode *status);
-
-#endif /* #if !UCONFIG_NO_FORMATTING */
-
-#endif
-