Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1741 insertions, 0 deletions

diff --git a/intl/icu/source/i18n/unicode/udat.h b/intl/icu/source/i18n/unicode/udat.h
new file mode 100644
index 0000000000..3823dc88c4
--- /dev/null
+++ b/intl/icu/source/i18n/unicode/udat.h
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+// © 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+/*
+ *******************************************************************************
+ * Copyright (C) 1996-2016, International Business Machines
+ * Corporation and others. All Rights Reserved.
+ *******************************************************************************
+*/
+
+#ifndef UDAT_H
+#define UDAT_H
+
+#include "unicode/utypes.h"
+
+#if !UCONFIG_NO_FORMATTING
+
+#include "unicode/ucal.h"
+#include "unicode/unum.h"
+#include "unicode/udisplaycontext.h"
+#include "unicode/ufieldpositer.h"
+
+#if U_SHOW_CPLUSPLUS_API
+#include "unicode/localpointer.h"
+#endif   // U_SHOW_CPLUSPLUS_API
+
+/**
+ * \file
+ * \brief C API: DateFormat
+ *
+ * <h2> Date Format C API</h2>
+ *
+ * Date Format C API  consists of functions that convert dates and
+ * times from their internal representations to textual form and back again in a
+ * language-independent manner. Converting from the internal representation (milliseconds
+ * since midnight, January 1, 1970) to text is known as "formatting," and converting
+ * from text to millis is known as "parsing."  We currently define only one concrete
+ * structure UDateFormat, which can handle pretty much all normal
+ * date formatting and parsing actions.
+ * <P>
+ * Date Format helps you to format and parse dates for any locale. Your code can
+ * be completely independent of the locale conventions for months, days of the
+ * week, or even the calendar format: lunar vs. solar.
+ * <P>
+ * To format a date for the current Locale with default time and date style,
+ * use one of the static factory methods:
+ * <pre>
+ * \code
+ *  UErrorCode status = U_ZERO_ERROR;
+ *  UChar *myString;
+ *  int32_t myStrlen = 0;
+ *  UDateFormat* dfmt = udat_open(UDAT_DEFAULT, UDAT_DEFAULT, NULL, NULL, -1, NULL, -1, &status);
+ *  myStrlen = udat_format(dfmt, myDate, NULL, myStrlen, NULL, &status);
+ *  if (status==U_BUFFER_OVERFLOW_ERROR){
+ *      status=U_ZERO_ERROR;
+ *      myString=(UChar*)malloc(sizeof(UChar) * (myStrlen+1) );
+ *      udat_format(dfmt, myDate, myString, myStrlen+1, NULL, &status);
+ *  }
+ * \endcode
+ * </pre>
+ * If you are formatting multiple numbers, it is more efficient to get the
+ * format and use it multiple times so that the system doesn't have to fetch the
+ * information about the local language and country conventions multiple times.
+ * <pre>
+ * \code
+ *  UErrorCode status = U_ZERO_ERROR;
+ *  int32_t i, myStrlen = 0;
+ *  UChar* myString;
+ *  char buffer[1024];
+ *  UDate myDateArr[] = { 0.0, 100000000.0, 2000000000.0 }; // test values
+ *  UDateFormat* df = udat_open(UDAT_DEFAULT, UDAT_DEFAULT, NULL, NULL, -1, NULL, 0, &status);
+ *  for (i = 0; i < 3; i++) {
+ *      myStrlen = udat_format(df, myDateArr[i], NULL, myStrlen, NULL, &status);
+ *      if(status == U_BUFFER_OVERFLOW_ERROR){
+ *          status = U_ZERO_ERROR;
+ *          myString = (UChar*)malloc(sizeof(UChar) * (myStrlen+1) );
+ *          udat_format(df, myDateArr[i], myString, myStrlen+1, NULL, &status);
+ *          printf("%s\n", u_austrcpy(buffer, myString) );
+ *          free(myString);
+ *      }
+ *  }
+ * \endcode
+ * </pre>
+ * To get specific fields of a date, you can use UFieldPosition to
+ * get specific fields.
+ * <pre>
+ * \code
+ *  UErrorCode status = U_ZERO_ERROR;
+ *  UFieldPosition pos;
+ *  UChar *myString;
+ *  int32_t myStrlen = 0;
+ *  char buffer[1024];
+ *
+ *  pos.field = 1;  // Same as the DateFormat::EField enum
+ *  UDateFormat* dfmt = udat_open(UDAT_DEFAULT, UDAT_DEFAULT, NULL, -1, NULL, 0, &status);
+ *  myStrlen = udat_format(dfmt, myDate, NULL, myStrlen, &pos, &status);
+ *  if (status==U_BUFFER_OVERFLOW_ERROR){
+ *      status=U_ZERO_ERROR;
+ *      myString=(UChar*)malloc(sizeof(UChar) * (myStrlen+1) );
+ *      udat_format(dfmt, myDate, myString, myStrlen+1, &pos, &status);
+ *  }
+ *  printf("date format: %s\n", u_austrcpy(buffer, myString));
+ *  buffer[pos.endIndex] = 0;   // NULL terminate the string.
+ *  printf("UFieldPosition position equals %s\n", &buffer[pos.beginIndex]);
+ * \endcode
+ * </pre>
+ * To format a date for a different Locale, specify it in the call to
+ * udat_open()
+ * <pre>
+ * \code
+ *        UDateFormat* df = udat_open(UDAT_SHORT, UDAT_SHORT, "fr_FR", NULL, -1, NULL, 0, &status);
+ * \endcode
+ * </pre>
+ * You can use a DateFormat API udat_parse() to parse.
+ * <pre>
+ * \code
+ *  UErrorCode status = U_ZERO_ERROR;
+ *  int32_t parsepos=0;
+ *  UDate myDate = udat_parse(df, myString, u_strlen(myString), &parsepos, &status);
+ * \endcode
+ * </pre>
+ *  You can pass in different options for the arguments for date and time style
+ *  to control the length of the result; from SHORT to MEDIUM to LONG to FULL.
+ *  The exact result depends on the locale, but generally:
+ *  see UDateFormatStyle for more details
+ * <ul type=round>
+ *   <li>   UDAT_SHORT is completely numeric, such as 12/13/52 or 3:30pm
+ *   <li>   UDAT_MEDIUM is longer, such as Jan 12, 1952
+ *   <li>   UDAT_LONG is longer, such as January 12, 1952 or 3:30:32pm
+ *   <li>   UDAT_FULL is pretty completely specified, such as
+ *          Tuesday, April 12, 1952 AD or 3:30:42pm PST.
+ * </ul>
+ * You can also set the time zone on the format if you wish.
+ * <P>
+ * You can also use forms of the parse and format methods with Parse Position and
+ * UFieldPosition to allow you to
+ * <ul type=round>
+ *   <li>   Progressively parse through pieces of a string.
+ *   <li>   Align any particular field, or find out where it is for selection
+ *          on the screen.
+ * </ul>
+ * <p><strong>Date and Time Patterns:</strong></p>
+ *
+ * <p>Date and time formats are specified by <em>date and time pattern</em> strings.
+ * Within date and time pattern strings, all unquoted ASCII letters [A-Za-z] are reserved
+ * as pattern letters representing calendar fields. <code>UDateFormat</code> supports
+ * the date and time formatting algorithm and pattern letters defined by
+ * <a href="http://www.unicode.org/reports/tr35/tr35-dates.html#Date_Field_Symbol_Table">UTS#35
+ * Unicode Locale Data Markup Language (LDML)</a> and further documented for ICU in the
+ * <a href="https://unicode-org.github.io/icu/userguide/format_parse/datetime#date-field-symbol-table">ICU
+ * User Guide</a>.</p>
+ */
+
+/** A date formatter.
+ *  For usage in C programs.
+ *  @stable ICU 2.6
+ */
+typedef void* UDateFormat;
+
+/** The possible date/time format styles
+ *  @stable ICU 2.6
+ */
+typedef enum UDateFormatStyle {
+    /** Full style */
+    UDAT_FULL,
+    /** Long style */
+    UDAT_LONG,
+    /** Medium style */
+    UDAT_MEDIUM,
+    /** Short style */
+    UDAT_SHORT,
+    /** Default style */
+    UDAT_DEFAULT = UDAT_MEDIUM,
+
+    /** Bitfield for relative date */
+    UDAT_RELATIVE = (1 << 7),
+
+    UDAT_FULL_RELATIVE = UDAT_FULL | UDAT_RELATIVE,
+
+    UDAT_LONG_RELATIVE = UDAT_LONG | UDAT_RELATIVE,
+
+    UDAT_MEDIUM_RELATIVE = UDAT_MEDIUM | UDAT_RELATIVE,
+
+    UDAT_SHORT_RELATIVE = UDAT_SHORT | UDAT_RELATIVE,
+
+
+    /** No style */
+    UDAT_NONE = -1,
+
+    /**
+     * Use the pattern given in the parameter to udat_open
+     * @see udat_open
+     * @stable ICU 50
+     */
+    UDAT_PATTERN = -2,
+
+#ifndef U_HIDE_INTERNAL_API
+    /** @internal alias to UDAT_PATTERN */
+    UDAT_IGNORE = UDAT_PATTERN
+#endif /* U_HIDE_INTERNAL_API */
+} UDateFormatStyle;
+
+/* Skeletons for dates. */
+
+/**
+ * Constant for date skeleton with year.
+ * @stable ICU 4.0
+ */
+#define UDAT_YEAR                       "y"
+/**
+ * Constant for date skeleton with quarter.
+ * @stable ICU 51
+ */
+#define UDAT_QUARTER                    "QQQQ"
+/**
+ * Constant for date skeleton with abbreviated quarter.
+ * @stable ICU 51
+ */
+#define UDAT_ABBR_QUARTER               "QQQ"
+/**
+ * Constant for date skeleton with year and quarter.
+ * @stable ICU 4.0
+ */
+#define UDAT_YEAR_QUARTER               "yQQQQ"
+/**
+ * Constant for date skeleton with year and abbreviated quarter.
+ * @stable ICU 4.0
+ */
+#define UDAT_YEAR_ABBR_QUARTER          "yQQQ"
+/**
+ * Constant for date skeleton with month.
+ * @stable ICU 4.0
+ */
+#define UDAT_MONTH                      "MMMM"
+/**
+ * Constant for date skeleton with abbreviated month.
+ * @stable ICU 4.0
+ */
+#define UDAT_ABBR_MONTH                 "MMM"
+/**
+ * Constant for date skeleton with numeric month.
+ * @stable ICU 4.0
+ */
+#define UDAT_NUM_MONTH                  "M"
+/**
+ * Constant for date skeleton with year and month.
+ * @stable ICU 4.0
+ */
+#define UDAT_YEAR_MONTH                 "yMMMM"
+/**
+ * Constant for date skeleton with year and abbreviated month.
+ * @stable ICU 4.0
+ */
+#define UDAT_YEAR_ABBR_MONTH            "yMMM"
+/**
+ * Constant for date skeleton with year and numeric month.
+ * @stable ICU 4.0
+ */
+#define UDAT_YEAR_NUM_MONTH             "yM"
+/**
+ * Constant for date skeleton with day.
+ * @stable ICU 4.0
+ */
+#define UDAT_DAY                        "d"
+/**
+ * Constant for date skeleton with year, month, and day.
+ * Used in combinations date + time, date + time + zone, or time + zone.
+ * @stable ICU 4.0
+ */
+#define UDAT_YEAR_MONTH_DAY             "yMMMMd"
+/**
+ * Constant for date skeleton with year, abbreviated month, and day.
+ * Used in combinations date + time, date + time + zone, or time + zone.
+ * @stable ICU 4.0
+ */
+#define UDAT_YEAR_ABBR_MONTH_DAY        "yMMMd"
+/**
+ * Constant for date skeleton with year, numeric month, and day.
+ * Used in combinations date + time, date + time + zone, or time + zone.
+ * @stable ICU 4.0
+ */
+#define UDAT_YEAR_NUM_MONTH_DAY         "yMd"
+/**
+ * Constant for date skeleton with weekday.
+ * @stable ICU 51
+ */
+#define UDAT_WEEKDAY                    "EEEE"
+/**
+ * Constant for date skeleton with abbreviated weekday.
+ * @stable ICU 51
+ */
+#define UDAT_ABBR_WEEKDAY               "E"
+/**
+ * Constant for date skeleton with year, month, weekday, and day.
+ * Used in combinations date + time, date + time + zone, or time + zone.
+ * @stable ICU 4.0
+ */
+#define UDAT_YEAR_MONTH_WEEKDAY_DAY     "yMMMMEEEEd"
+/**
+ * Constant for date skeleton with year, abbreviated month, weekday, and day.
+ * Used in combinations date + time, date + time + zone, or time + zone.
+ * @stable ICU 4.0
+ */
+#define UDAT_YEAR_ABBR_MONTH_WEEKDAY_DAY "yMMMEd"
+/**
+ * Constant for date skeleton with year, numeric month, weekday, and day.
+ * Used in combinations date + time, date + time + zone, or time + zone.
+ * @stable ICU 4.0
+ */
+#define UDAT_YEAR_NUM_MONTH_WEEKDAY_DAY "yMEd"
+/**
+ * Constant for date skeleton with long month and day.
+ * Used in combinations date + time, date + time + zone, or time + zone.
+ * @stable ICU 4.0
+ */
+#define UDAT_MONTH_DAY                  "MMMMd"
+/**
+ * Constant for date skeleton with abbreviated month and day.
+ * Used in combinations date + time, date + time + zone, or time + zone.
+ * @stable ICU 4.0
+ */
+#define UDAT_ABBR_MONTH_DAY             "MMMd"
+/**
+ * Constant for date skeleton with numeric month and day.
+ * Used in combinations date + time, date + time + zone, or time + zone.
+ * @stable ICU 4.0
+ */
+#define UDAT_NUM_MONTH_DAY              "Md"
+/**
+ * Constant for date skeleton with month, weekday, and day.
+ * Used in combinations date + time, date + time + zone, or time + zone.
+ * @stable ICU 4.0
+ */
+#define UDAT_MONTH_WEEKDAY_DAY          "MMMMEEEEd"
+/**
+ * Constant for date skeleton with abbreviated month, weekday, and day.
+ * Used in combinations date + time, date + time + zone, or time + zone.
+ * @stable ICU 4.0
+ */
+#define UDAT_ABBR_MONTH_WEEKDAY_DAY     "MMMEd"
+/**
+ * Constant for date skeleton with numeric month, weekday, and day.
+ * Used in combinations date + time, date + time + zone, or time + zone.
+ * @stable ICU 4.0
+ */
+#define UDAT_NUM_MONTH_WEEKDAY_DAY      "MEd"
+
+/* Skeletons for times. */
+
+/**
+ * Constant for date skeleton with hour, with the locale's preferred hour format (12 or 24).
+ * @stable ICU 4.0
+ */
+#define UDAT_HOUR                       "j"
+/**
+ * Constant for date skeleton with hour in 24-hour presentation.
+ * @stable ICU 51
+ */
+#define UDAT_HOUR24                     "H"
+/**
+ * Constant for date skeleton with minute.
+ * @stable ICU 51
+ */
+#define UDAT_MINUTE                     "m"
+/**
+ * Constant for date skeleton with hour and minute, with the locale's preferred hour format (12 or 24).
+ * Used in combinations date + time, date + time + zone, or time + zone.
+ * @stable ICU 4.0
+ */
+#define UDAT_HOUR_MINUTE                "jm"
+/**
+ * Constant for date skeleton with hour and minute in 24-hour presentation.
+ * Used in combinations date + time, date + time + zone, or time + zone.
+ * @stable ICU 4.0
+ */
+#define UDAT_HOUR24_MINUTE              "Hm"
+/**
+ * Constant for date skeleton with second.
+ * @stable ICU 51
+ */
+#define UDAT_SECOND                     "s"
+/**
+ * Constant for date skeleton with hour, minute, and second,
+ * with the locale's preferred hour format (12 or 24).
+ * Used in combinations date + time, date + time + zone, or time + zone.
+ * @stable ICU 4.0
+ */
+#define UDAT_HOUR_MINUTE_SECOND         "jms"
+/**
+ * Constant for date skeleton with hour, minute, and second in
+ * 24-hour presentation.
+ * Used in combinations date + time, date + time + zone, or time + zone.
+ * @stable ICU 4.0
+ */
+#define UDAT_HOUR24_MINUTE_SECOND       "Hms"
+/**
+ * Constant for date skeleton with minute and second.
+ * Used in combinations date + time, date + time + zone, or time + zone.
+ * @stable ICU 4.0
+ */
+#define UDAT_MINUTE_SECOND              "ms"
+
+/* Skeletons for time zones. */
+
+/**
+ * Constant for <i>generic location format</i>, such as Los Angeles Time;
+ * used in combinations date + time + zone, or time + zone.
+ * @see <a href="http://unicode.org/reports/tr35/#Date_Format_Patterns">LDML Date Format Patterns</a>
+ * @see <a href="http://unicode.org/reports/tr35/#Time_Zone_Fallback">LDML Time Zone Fallback</a>
+ * @stable ICU 51
+ */
+#define UDAT_LOCATION_TZ "VVVV"
+/**
+ * Constant for <i>generic non-location format</i>, such as Pacific Time;
+ * used in combinations date + time + zone, or time + zone.
+ * @see <a href="http://unicode.org/reports/tr35/#Date_Format_Patterns">LDML Date Format Patterns</a>
+ * @see <a href="http://unicode.org/reports/tr35/#Time_Zone_Fallback">LDML Time Zone Fallback</a>
+ * @stable ICU 51
+ */
+#define UDAT_GENERIC_TZ "vvvv"
+/**
+ * Constant for <i>generic non-location format</i>, abbreviated if possible, such as PT;
+ * used in combinations date + time + zone, or time + zone.
+ * @see <a href="http://unicode.org/reports/tr35/#Date_Format_Patterns">LDML Date Format Patterns</a>
+ * @see <a href="http://unicode.org/reports/tr35/#Time_Zone_Fallback">LDML Time Zone Fallback</a>
+ * @stable ICU 51
+ */
+#define UDAT_ABBR_GENERIC_TZ "v"
+/**
+ * Constant for <i>specific non-location format</i>, such as Pacific Daylight Time;
+ * used in combinations date + time + zone, or time + zone.
+ * @see <a href="http://unicode.org/reports/tr35/#Date_Format_Patterns">LDML Date Format Patterns</a>
+ * @see <a href="http://unicode.org/reports/tr35/#Time_Zone_Fallback">LDML Time Zone Fallback</a>
+ * @stable ICU 51
+ */
+#define UDAT_SPECIFIC_TZ "zzzz"
+/**
+ * Constant for <i>specific non-location format</i>, abbreviated if possible, such as PDT;
+ * used in combinations date + time + zone, or time + zone.
+ * @see <a href="http://unicode.org/reports/tr35/#Date_Format_Patterns">LDML Date Format Patterns</a>
+ * @see <a href="http://unicode.org/reports/tr35/#Time_Zone_Fallback">LDML Time Zone Fallback</a>
+ * @stable ICU 51
+ */
+#define UDAT_ABBR_SPECIFIC_TZ "z"
+/**
+ * Constant for <i>localized GMT/UTC format</i>, such as GMT+8:00 or HPG-8:00;
+ * used in combinations date + time + zone, or time + zone.
+ * @see <a href="http://unicode.org/reports/tr35/#Date_Format_Patterns">LDML Date Format Patterns</a>
+ * @see <a href="http://unicode.org/reports/tr35/#Time_Zone_Fallback">LDML Time Zone Fallback</a>
+ * @stable ICU 51
+ */
+#define UDAT_ABBR_UTC_TZ "ZZZZ"
+
+/* deprecated skeleton constants */
+
+#ifndef U_HIDE_DEPRECATED_API
+/**
+ * Constant for date skeleton with standalone month.
+ * @deprecated ICU 50 Use UDAT_MONTH instead.
+ */
+#define UDAT_STANDALONE_MONTH           "LLLL"
+/**
+ * Constant for date skeleton with standalone abbreviated month.
+ * @deprecated ICU 50 Use UDAT_ABBR_MONTH instead.
+ */
+#define UDAT_ABBR_STANDALONE_MONTH      "LLL"
+
+/**
+ * Constant for date skeleton with hour, minute, and generic timezone.
+ * @deprecated ICU 50 Use instead UDAT_HOUR_MINUTE UDAT_ABBR_GENERIC_TZ or some other timezone presentation.
+ */
+#define UDAT_HOUR_MINUTE_GENERIC_TZ     "jmv"
+/**
+ * Constant for date skeleton with hour, minute, and timezone.
+ * @deprecated ICU 50 Use instead UDAT_HOUR_MINUTE UDAT_ABBR_SPECIFIC_TZ or some other timezone presentation.
+ */
+#define UDAT_HOUR_MINUTE_TZ             "jmz"
+/**
+ * Constant for date skeleton with hour and generic timezone.
+ * @deprecated ICU 50 Use instead UDAT_HOUR UDAT_ABBR_GENERIC_TZ or some other timezone presentation.
+ */
+#define UDAT_HOUR_GENERIC_TZ            "jv"
+/**
+ * Constant for date skeleton with hour and timezone.
+ * @deprecated ICU 50 Use instead UDAT_HOUR UDAT_ABBR_SPECIFIC_TZ or some other timezone presentation.
+ */
+#define UDAT_HOUR_TZ                    "jz"
+#endif  /* U_HIDE_DEPRECATED_API */
+
+#ifndef U_HIDE_INTERNAL_API
+/**
+ * Constant for Unicode string name of new (in 2019) Japanese calendar era,
+ * root/English abbreviated version (ASCII-range characters).
+ * @internal
+ */
+#define JP_ERA_2019_ROOT                "Reiwa"
+/**
+ * Constant for Unicode string name of new (in 2019) Japanese calendar era,
+ * Japanese abbreviated version (Han, or fullwidth Latin for testing).
+ * @internal
+ */
+#define JP_ERA_2019_JA                  "\\u4EE4\\u548C"
+/**
+ * Constant for Unicode string name of new (in 2019) Japanese calendar era,
+ * root and Japanese narrow version (ASCII-range characters).
+ * @internal
+ */
+#define JP_ERA_2019_NARROW              "R"
+#endif  // U_HIDE_INTERNAL_API
+
+/**
+ * FieldPosition and UFieldPosition selectors for format fields
+ * defined by DateFormat and UDateFormat.
+ * @stable ICU 3.0
+ */
+typedef enum UDateFormatField {
+    /**
+     * FieldPosition and UFieldPosition selector for 'G' field alignment,
+     * corresponding to the UCAL_ERA field.
+     * @stable ICU 3.0
+     */
+    UDAT_ERA_FIELD = 0,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'y' field alignment,
+     * corresponding to the UCAL_YEAR field.
+     * @stable ICU 3.0
+     */
+    UDAT_YEAR_FIELD = 1,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'M' field alignment,
+     * corresponding to the UCAL_MONTH field.
+     * @stable ICU 3.0
+     */
+    UDAT_MONTH_FIELD = 2,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'd' field alignment,
+     * corresponding to the UCAL_DATE field.
+     * @stable ICU 3.0
+     */
+    UDAT_DATE_FIELD = 3,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'k' field alignment,
+     * corresponding to the UCAL_HOUR_OF_DAY field.
+     * UDAT_HOUR_OF_DAY1_FIELD is used for the one-based 24-hour clock.
+     * For example, 23:59 + 01:00 results in 24:59.
+     * @stable ICU 3.0
+     */
+    UDAT_HOUR_OF_DAY1_FIELD = 4,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'H' field alignment,
+     * corresponding to the UCAL_HOUR_OF_DAY field.
+     * UDAT_HOUR_OF_DAY0_FIELD is used for the zero-based 24-hour clock.
+     * For example, 23:59 + 01:00 results in 00:59.
+     * @stable ICU 3.0
+     */
+    UDAT_HOUR_OF_DAY0_FIELD = 5,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'm' field alignment,
+     * corresponding to the UCAL_MINUTE field.
+     * @stable ICU 3.0
+     */
+    UDAT_MINUTE_FIELD = 6,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 's' field alignment,
+     * corresponding to the UCAL_SECOND field.
+     * @stable ICU 3.0
+     */
+    UDAT_SECOND_FIELD = 7,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'S' field alignment,
+     * corresponding to the UCAL_MILLISECOND field.
+     *
+     * Note: Time formats that use 'S' can display a maximum of three
+     * significant digits for fractional seconds, corresponding to millisecond
+     * resolution and a fractional seconds sub-pattern of SSS. If the
+     * sub-pattern is S or SS, the fractional seconds value will be truncated
+     * (not rounded) to the number of display places specified. If the
+     * fractional seconds sub-pattern is longer than SSS, the additional
+     * display places will be filled with zeros.
+     * @stable ICU 3.0
+     */
+    UDAT_FRACTIONAL_SECOND_FIELD = 8,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'E' field alignment,
+     * corresponding to the UCAL_DAY_OF_WEEK field.
+     * @stable ICU 3.0
+     */
+    UDAT_DAY_OF_WEEK_FIELD = 9,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'D' field alignment,
+     * corresponding to the UCAL_DAY_OF_YEAR field.
+     * @stable ICU 3.0
+     */
+    UDAT_DAY_OF_YEAR_FIELD = 10,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'F' field alignment,
+     * corresponding to the UCAL_DAY_OF_WEEK_IN_MONTH field.
+     * @stable ICU 3.0
+     */
+    UDAT_DAY_OF_WEEK_IN_MONTH_FIELD = 11,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'w' field alignment,
+     * corresponding to the UCAL_WEEK_OF_YEAR field.
+     * @stable ICU 3.0
+     */
+    UDAT_WEEK_OF_YEAR_FIELD = 12,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'W' field alignment,
+     * corresponding to the UCAL_WEEK_OF_MONTH field.
+     * @stable ICU 3.0
+     */
+    UDAT_WEEK_OF_MONTH_FIELD = 13,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'a' field alignment,
+     * corresponding to the UCAL_AM_PM field.
+     * @stable ICU 3.0
+     */
+    UDAT_AM_PM_FIELD = 14,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'h' field alignment,
+     * corresponding to the UCAL_HOUR field.
+     * UDAT_HOUR1_FIELD is used for the one-based 12-hour clock.
+     * For example, 11:30 PM + 1 hour results in 12:30 AM.
+     * @stable ICU 3.0
+     */
+    UDAT_HOUR1_FIELD = 15,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'K' field alignment,
+     * corresponding to the UCAL_HOUR field.
+     * UDAT_HOUR0_FIELD is used for the zero-based 12-hour clock.
+     * For example, 11:30 PM + 1 hour results in 00:30 AM.
+     * @stable ICU 3.0
+     */
+    UDAT_HOUR0_FIELD = 16,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'z' field alignment,
+     * corresponding to the UCAL_ZONE_OFFSET and
+     * UCAL_DST_OFFSET fields.
+     * @stable ICU 3.0
+     */
+    UDAT_TIMEZONE_FIELD = 17,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'Y' field alignment,
+     * corresponding to the UCAL_YEAR_WOY field.
+     * @stable ICU 3.0
+     */
+    UDAT_YEAR_WOY_FIELD = 18,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'e' field alignment,
+     * corresponding to the UCAL_DOW_LOCAL field.
+     * @stable ICU 3.0
+     */
+    UDAT_DOW_LOCAL_FIELD = 19,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'u' field alignment,
+     * corresponding to the UCAL_EXTENDED_YEAR field.
+     * @stable ICU 3.0
+     */
+    UDAT_EXTENDED_YEAR_FIELD = 20,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'g' field alignment,
+     * corresponding to the UCAL_JULIAN_DAY field.
+     * @stable ICU 3.0
+     */
+    UDAT_JULIAN_DAY_FIELD = 21,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'A' field alignment,
+     * corresponding to the UCAL_MILLISECONDS_IN_DAY field.
+     * @stable ICU 3.0
+     */
+    UDAT_MILLISECONDS_IN_DAY_FIELD = 22,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'Z' field alignment,
+     * corresponding to the UCAL_ZONE_OFFSET and
+     * UCAL_DST_OFFSET fields.
+     * @stable ICU 3.0
+     */
+    UDAT_TIMEZONE_RFC_FIELD = 23,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'v' field alignment,
+     * corresponding to the UCAL_ZONE_OFFSET field.
+     * @stable ICU 3.4
+     */
+    UDAT_TIMEZONE_GENERIC_FIELD = 24,
+    /**
+     * FieldPosition selector for 'c' field alignment,
+     * corresponding to the {@link #UCAL_DOW_LOCAL} field.
+     * This displays the stand alone day name, if available.
+     * @stable ICU 3.4
+     */
+    UDAT_STANDALONE_DAY_FIELD = 25,
+
+    /**
+     * FieldPosition selector for 'L' field alignment,
+     * corresponding to the {@link #UCAL_MONTH} field.
+     * This displays the stand alone month name, if available.
+     * @stable ICU 3.4
+     */
+    UDAT_STANDALONE_MONTH_FIELD = 26,
+
+    /**
+     * FieldPosition selector for "Q" field alignment,
+     * corresponding to quarters. This is implemented
+     * using the {@link #UCAL_MONTH} field. This
+     * displays the quarter.
+     * @stable ICU 3.6
+     */
+    UDAT_QUARTER_FIELD = 27,
+
+    /**
+     * FieldPosition selector for the "q" field alignment,
+     * corresponding to stand-alone quarters. This is
+     * implemented using the {@link #UCAL_MONTH} field.
+     * This displays the stand-alone quarter.
+     * @stable ICU 3.6
+     */
+    UDAT_STANDALONE_QUARTER_FIELD = 28,
+
+    /**
+     * FieldPosition and UFieldPosition selector for 'V' field alignment,
+     * corresponding to the UCAL_ZONE_OFFSET field.
+     * @stable ICU 3.8
+     */
+    UDAT_TIMEZONE_SPECIAL_FIELD = 29,
+
+    /**
+     * FieldPosition selector for "U" field alignment,
+     * corresponding to cyclic year names. This is implemented
+     * using the {@link #UCAL_YEAR} field. This displays
+     * the cyclic year name, if available.
+     * @stable ICU 49
+     */
+    UDAT_YEAR_NAME_FIELD = 30,
+
+    /**
+     * FieldPosition selector for 'O' field alignment,
+     * corresponding to the UCAL_ZONE_OFFSET and UCAL_DST_OFFSETfields.
+     * This displays the localized GMT format.
+     * @stable ICU 51
+     */
+    UDAT_TIMEZONE_LOCALIZED_GMT_OFFSET_FIELD = 31,
+
+    /**
+     * FieldPosition selector for 'X' field alignment,
+     * corresponding to the UCAL_ZONE_OFFSET and UCAL_DST_OFFSETfields.
+     * This displays the ISO 8601 local time offset format or UTC indicator ("Z").
+     * @stable ICU 51
+     */
+    UDAT_TIMEZONE_ISO_FIELD = 32,
+
+    /**
+     * FieldPosition selector for 'x' field alignment,
+     * corresponding to the UCAL_ZONE_OFFSET and UCAL_DST_OFFSET fields.
+     * This displays the ISO 8601 local time offset format.
+     * @stable ICU 51
+     */
+    UDAT_TIMEZONE_ISO_LOCAL_FIELD = 33,
+
+#ifndef U_HIDE_INTERNAL_API
+    /**
+     * FieldPosition and UFieldPosition selector for 'r' field alignment,
+     * no directly corresponding UCAL_ field.
+     * @internal ICU 53
+     */
+    UDAT_RELATED_YEAR_FIELD = 34,
+#endif  /* U_HIDE_INTERNAL_API */
+
+    /**
+     * FieldPosition selector for 'b' field alignment.
+     * Displays midnight and noon for 12am and 12pm, respectively, if available;
+     * otherwise fall back to AM / PM.
+     * @stable ICU 57
+     */
+    UDAT_AM_PM_MIDNIGHT_NOON_FIELD = 35,
+
+    /* FieldPosition selector for 'B' field alignment.
+     * Displays flexible day periods, such as "in the morning", if available.
+     * @stable ICU 57
+     */
+    UDAT_FLEXIBLE_DAY_PERIOD_FIELD = 36,
+
+#ifndef U_HIDE_INTERNAL_API
+    /**
+     * FieldPosition and UFieldPosition selector for time separator,
+     * no corresponding UCAL_ field. No pattern character is currently
+     * defined for this.
+     * @internal
+     */
+    UDAT_TIME_SEPARATOR_FIELD = 37,
+#endif  /* U_HIDE_INTERNAL_API */
+
+#ifndef U_HIDE_DEPRECATED_API
+    /**
+     * Number of FieldPosition and UFieldPosition selectors for
+     * DateFormat and UDateFormat.
+     * Valid selectors range from 0 to UDAT_FIELD_COUNT-1.
+     * @deprecated ICU 58 The numeric value may change over time, see ICU ticket #12420.
+     */
+    UDAT_FIELD_COUNT = 38
+#endif  /* U_HIDE_DEPRECATED_API */
+} UDateFormatField;
+
+
+#ifndef U_HIDE_INTERNAL_API
+/**
+ * Is a pattern character defined for UDAT_TIME_SEPARATOR_FIELD?
+ * In ICU 55 it was COLON, but that was withdrawn in ICU 56.
+ * @internal ICU 56
+ */
+#define UDAT_HAS_PATTERN_CHAR_FOR_TIME_SEPARATOR 0
+#endif /* U_HIDE_INTERNAL_API */
+
+
+/**
+ * Maps from a UDateFormatField to the corresponding UCalendarDateFields.
+ *
+ * Note 1: Since the mapping is many-to-one, there is no inverse mapping.
+ *
+ * Note 2: There is no UErrorCode parameter, so in case of error (UDateFormatField is
+ * unknown or has no corresponding UCalendarDateFields value), the function returns the
+ * current value of UCAL_FIELD_COUNT. However, that value may change from release to
+ * release and is consequently deprecated. For a future-proof runtime way of checking
+ * for errors:
+ * a) First save the value returned by the function when it is passed an invalid value
+ *    such as "(UDateFormatField)-1".
+ * b) Then, to test for errors when passing some other UDateFormatField value, check
+ *     whether the function returns that saved value.
+ *
+ * @param field the UDateFormatField.
+ * @return the UCalendarDateField. In case of error (UDateFormatField is unknown or has
+ *   no corresponding UCalendarDateFields value) this will be the current value of
+ *   UCAL_FIELD_COUNT, but that value may change from release to release.
+ *   See Note 2 above.
+ * @stable ICU 4.4
+ */
+U_CAPI UCalendarDateFields U_EXPORT2
+udat_toCalendarDateField(UDateFormatField field);
+
+
+/**
+ * Open a new UDateFormat for formatting and parsing dates and times.
+ * A UDateFormat may be used to format dates in calls to {@link #udat_format },
+ * and to parse dates in calls to {@link #udat_parse }.
+ * @param timeStyle The style used to format times; one of UDAT_FULL, UDAT_LONG,
+ * UDAT_MEDIUM, UDAT_SHORT, UDAT_DEFAULT, or UDAT_NONE (relative time styles
+ * are not currently supported).
+ * When the pattern parameter is used, pass in UDAT_PATTERN for both timeStyle and dateStyle.
+ * @param dateStyle The style used to format dates; one of UDAT_FULL, UDAT_LONG,
+ * UDAT_MEDIUM, UDAT_SHORT, UDAT_DEFAULT, UDAT_FULL_RELATIVE, UDAT_LONG_RELATIVE,
+ * UDAT_MEDIUM_RELATIVE, UDAT_SHORT_RELATIVE, or UDAT_NONE.
+ * When the pattern parameter is used, pass in UDAT_PATTERN for both timeStyle and dateStyle.
+ * As currently implemented,
+ * relative date formatting only affects a limited range of calendar days before or
+ * after the current date, based on the CLDR &lt;field type="day"&gt;/&lt;relative&gt; data: For
+ * example, in English, "Yesterday", "Today", and "Tomorrow". Outside of this range,
+ * dates are formatted using the corresponding non-relative style.
+ * @param locale The locale specifying the formatting conventions
+ * @param tzID A timezone ID specifying the timezone to use.  If 0, use
+ * the default timezone.
+ * @param tzIDLength The length of tzID, or -1 if null-terminated.
+ * @param pattern A pattern specifying the format to use.
+ * @param patternLength The number of characters in the pattern, or -1 if null-terminated.
+ * @param status A pointer to an UErrorCode to receive any errors
+ * @return A pointer to a UDateFormat to use for formatting dates and times, or 0 if
+ * an error occurred.
+ * @stable ICU 2.0
+ */
+U_CAPI UDateFormat* U_EXPORT2
+udat_open(UDateFormatStyle  timeStyle,
+          UDateFormatStyle  dateStyle,
+          const char        *locale,
+          const UChar       *tzID,
+          int32_t           tzIDLength,
+          const UChar       *pattern,
+          int32_t           patternLength,
+          UErrorCode        *status);
+
+
+/**
+* Close a UDateFormat.
+* Once closed, a UDateFormat may no longer be used.
+* @param format The formatter to close.
+* @stable ICU 2.0
+*/
+U_CAPI void U_EXPORT2
+udat_close(UDateFormat* format);
+
+
+/**
+ * DateFormat boolean attributes
+ *
+ * @stable ICU 53
+ */
+typedef enum UDateFormatBooleanAttribute {
+   /**
+     * indicates whether whitespace is allowed. Includes trailing dot tolerance.
+     * @stable ICU 53
+     */
+    UDAT_PARSE_ALLOW_WHITESPACE = 0,
+    /**
+     * indicates tolerance of numeric data when String data may be assumed. eg: UDAT_YEAR_NAME_FIELD,
+     * UDAT_STANDALONE_MONTH_FIELD, UDAT_DAY_OF_WEEK_FIELD
+     * @stable ICU 53
+     */
+    UDAT_PARSE_ALLOW_NUMERIC = 1,
+    /**
+     * indicates tolerance of a partial literal match
+     * e.g. accepting "--mon-02-march-2011" for a pattern of "'--: 'EEE-WW-MMMM-yyyy"
+     * @stable ICU 56
+     */
+    UDAT_PARSE_PARTIAL_LITERAL_MATCH = 2,
+    /**
+     * indicates tolerance of pattern mismatch between input data and specified format pattern.
+     * e.g. accepting "September" for a month pattern of MMM ("Sep")
+     * @stable ICU 56
+     */
+    UDAT_PARSE_MULTIPLE_PATTERNS_FOR_MATCH = 3,
+
+    /* Do not conditionalize the following with #ifndef U_HIDE_DEPRECATED_API,
+     * it is needed for layout of DateFormat object. */
+#ifndef U_FORCE_HIDE_DEPRECATED_API
+    /**
+     * One more than the highest normal UDateFormatBooleanAttribute value.
+     * @deprecated ICU 58 The numeric value may change over time, see ICU ticket #12420.
+     */
+    UDAT_BOOLEAN_ATTRIBUTE_COUNT = 4
+#endif  // U_FORCE_HIDE_DEPRECATED_API
+} UDateFormatBooleanAttribute;
+
+/**
+ * Get a boolean attribute associated with a UDateFormat.
+ * An example would be a true value for a key of UDAT_PARSE_ALLOW_WHITESPACE indicating allowing whitespace leniency.
+ * If the formatter does not understand the attribute, -1 is returned.
+ * @param fmt The formatter to query.
+ * @param attr The attribute to query; e.g. UDAT_PARSE_ALLOW_WHITESPACE.
+ * @param status A pointer to an UErrorCode to receive any errors
+ * @return The value of attr.
+ * @stable ICU 53
+ */
+U_CAPI UBool U_EXPORT2
+udat_getBooleanAttribute(const UDateFormat* fmt, UDateFormatBooleanAttribute attr, UErrorCode* status);
+
+/**
+ * Set a boolean attribute associated with a UDateFormat.
+ * An example of a boolean attribute is parse leniency control.  If the formatter does not understand
+ * the attribute, the call is ignored.
+ * @param fmt The formatter to set.
+ * @param attr The attribute to set; one of UDAT_PARSE_ALLOW_WHITESPACE or UDAT_PARSE_ALLOW_NUMERIC
+ * @param newValue The new value of attr.
+ * @param status A pointer to an UErrorCode to receive any errors
+ * @stable ICU 53
+ */
+U_CAPI void U_EXPORT2
+udat_setBooleanAttribute(UDateFormat *fmt, UDateFormatBooleanAttribute attr, UBool newValue, UErrorCode* status);
+
+/**
+ * Hour Cycle.
+ * @stable ICU 67
+ */
+typedef enum UDateFormatHourCycle {
+    /**
+     * Hour in am/pm (0~11)
+     * @stable ICU 67
+     */
+    UDAT_HOUR_CYCLE_11,
+
+    /**
+     * Hour in am/pm (1~12)
+     * @stable ICU 67
+     */
+    UDAT_HOUR_CYCLE_12,
+
+    /**
+     * Hour in day (0~23)
+     * @stable ICU 67
+     */
+    UDAT_HOUR_CYCLE_23,
+
+    /**
+     * Hour in day (1~24)
+     * @stable ICU 67
+     */
+    UDAT_HOUR_CYCLE_24
+} UDateFormatHourCycle;
+
+#if U_SHOW_CPLUSPLUS_API
+
+U_NAMESPACE_BEGIN
+
+/**
+ * \class LocalUDateFormatPointer
+ * "Smart pointer" class, closes a UDateFormat via udat_close().
+ * For most methods see the LocalPointerBase base class.
+ *
+ * @see LocalPointerBase
+ * @see LocalPointer
+ * @stable ICU 4.4
+ */
+U_DEFINE_LOCAL_OPEN_POINTER(LocalUDateFormatPointer, UDateFormat, udat_close);
+
+U_NAMESPACE_END
+
+#endif
+
+/**
+ * Open a copy of a UDateFormat.
+ * This function performs a deep copy.
+ * @param fmt The format to copy
+ * @param status A pointer to an UErrorCode to receive any errors.
+ * @return A pointer to a UDateFormat identical to fmt.
+ * @stable ICU 2.0
+ */
+U_CAPI UDateFormat* U_EXPORT2
+udat_clone(const UDateFormat *fmt,
+       UErrorCode *status);
+
+/**
+* Format a date using a UDateFormat.
+* The date will be formatted using the conventions specified in {@link #udat_open }
+* @param format The formatter to use
+* @param dateToFormat The date to format
+* @param result A pointer to a buffer to receive the formatted number.
+* @param resultLength The maximum size of result.
+* @param position A pointer to a UFieldPosition.  On input, position->field
+* is read.  On output, position->beginIndex and position->endIndex indicate
+* the beginning and ending indices of field number position->field, if such
+* a field exists.  This parameter may be NULL, in which case no field
+* position data is returned.
+* @param status A pointer to an UErrorCode to receive any errors
+* @return The total buffer size needed; if greater than resultLength, the output was truncated.
+* @see udat_parse
+* @see UFieldPosition
+* @stable ICU 2.0
+*/
+U_CAPI int32_t U_EXPORT2
+udat_format(    const    UDateFormat*    format,
+                        UDate           dateToFormat,
+                        UChar*          result,
+                        int32_t         resultLength,
+                        UFieldPosition* position,
+                        UErrorCode*     status);
+
+/**
+* Format a date using an UDateFormat.
+* The date will be formatted using the conventions specified in {@link #udat_open }
+* @param format The formatter to use
+* @param calendar The calendar to format. The calendar instance might be
+*                 mutated if fields are not yet fully calculated, though
+*                 the function won't change the logical date and time held
+*                 by the instance.
+* @param result A pointer to a buffer to receive the formatted number.
+* @param capacity The maximum size of result.
+* @param position A pointer to a UFieldPosition.  On input, position->field
+* is read.  On output, position->beginIndex and position->endIndex indicate
+* the beginning and ending indices of field number position->field, if such
+* a field exists.  This parameter may be NULL, in which case no field
+* position data is returned.
+* @param status A pointer to an UErrorCode to receive any errors
+* @return The total buffer size needed; if greater than resultLength, the output was truncated.
+* @see udat_format
+* @see udat_parseCalendar
+* @see UFieldPosition
+* @stable ICU 55
+*/
+U_CAPI int32_t U_EXPORT2
+udat_formatCalendar(    const UDateFormat*  format,
+                        UCalendar*      calendar,
+                        UChar*          result,
+                        int32_t         capacity,
+                        UFieldPosition* position,
+                        UErrorCode*     status);
+
+/**
+* Format a date using a UDateFormat.
+* The date will be formatted using the conventions specified in {@link #udat_open}
+* @param format
+*          The formatter to use
+* @param dateToFormat
+*          The date to format
+* @param result
+*          A pointer to a buffer to receive the formatted number.
+* @param resultLength
+*          The maximum size of result.
+* @param fpositer
+*          A pointer to a UFieldPositionIterator created by {@link #ufieldpositer_open}
+*          (may be NULL if field position information is not needed). Any
+*          iteration information already present in the UFieldPositionIterator
+*          will be deleted, and the iterator will be reset to apply to the
+*          fields in the formatted string created by this function call; the
+*          field values provided by {@link #ufieldpositer_next} will be from the
+*          UDateFormatField enum.
+* @param status
+*          A pointer to a UErrorCode to receive any errors
+* @return
+*          The total buffer size needed; if greater than resultLength, the output was truncated.
+* @see udat_parse
+* @see UFieldPositionIterator
+* @stable ICU 55
+*/
+U_CAPI int32_t U_EXPORT2
+udat_formatForFields(   const UDateFormat* format,
+                        UDate           dateToFormat,
+                        UChar*          result,
+                        int32_t         resultLength,
+                        UFieldPositionIterator* fpositer,
+                        UErrorCode*     status);
+
+/**
+* Format a date using a UDateFormat.
+* The date will be formatted using the conventions specified in {@link #udat_open }
+* @param format
+*          The formatter to use
+* @param calendar
+*          The calendar to format. The calendar instance might be mutated if fields
+*          are not yet fully calculated, though the function won't change the logical
+*          date and time held by the instance.
+* @param result
+*          A pointer to a buffer to receive the formatted number.
+* @param capacity
+*          The maximum size of result.
+* @param fpositer
+*          A pointer to a UFieldPositionIterator created by {@link #ufieldpositer_open}
+*          (may be NULL if field position information is not needed). Any
+*          iteration information already present in the UFieldPositionIterator
+*          will be deleted, and the iterator will be reset to apply to the
+*          fields in the formatted string created by this function call; the
+*          field values provided by {@link #ufieldpositer_next} will be from the
+*          UDateFormatField enum.
+* @param status
+*          A pointer to a UErrorCode to receive any errors
+* @return
+*          The total buffer size needed; if greater than resultLength, the output was truncated.
+* @see udat_format
+* @see udat_parseCalendar
+* @see UFieldPositionIterator
+* @stable ICU 55
+*/
+U_CAPI int32_t U_EXPORT2
+udat_formatCalendarForFields( const UDateFormat* format,
+                        UCalendar*      calendar,
+                        UChar*          result,
+                        int32_t         capacity,
+                        UFieldPositionIterator* fpositer,
+                        UErrorCode*     status);
+
+
+/**
+* Parse a string into an date/time using a UDateFormat.
+* The date will be parsed using the conventions specified in {@link #udat_open }.
+* <P>
+* Note that the normal date formats associated with some calendars - such
+* as the Chinese lunar calendar - do not specify enough fields to enable
+* dates to be parsed unambiguously. In the case of the Chinese lunar
+* calendar, while the year within the current 60-year cycle is specified,
+* the number of such cycles since the start date of the calendar (in the
+* UCAL_ERA field of the UCalendar object) is not normally part of the format,
+* and parsing may assume the wrong era. For cases such as this it is
+* recommended that clients parse using udat_parseCalendar with the UCalendar
+* passed in set to the current date, or to a date within the era/cycle that
+* should be assumed if absent in the format.
+*
+* @param format The formatter to use.
+* @param text The text to parse.
+* @param textLength The length of text, or -1 if null-terminated.
+* @param parsePos If not 0, on input a pointer to an integer specifying the offset at which
+* to begin parsing.  If not 0, on output the offset at which parsing ended.
+* @param status A pointer to an UErrorCode to receive any errors
+* @return The value of the parsed date/time
+* @see udat_format
+* @stable ICU 2.0
+*/
+U_CAPI UDate U_EXPORT2
+udat_parse(const    UDateFormat*    format,
+           const    UChar*          text,
+                    int32_t         textLength,
+                    int32_t         *parsePos,
+                    UErrorCode      *status);
+
+/**
+* Parse a string into an date/time using a UDateFormat.
+* The date will be parsed using the conventions specified in {@link #udat_open }.
+* @param format The formatter to use.
+* @param calendar A calendar set on input to the date and time to be used for
+*                 missing values in the date/time string being parsed, and set
+*                 on output to the parsed date/time. When the calendar type is
+*                 different from the internal calendar held by the UDateFormat
+*                 instance, the internal calendar will be cloned to a work
+*                 calendar set to the same milliseconds and time zone as this
+*                 calendar parameter, field values will be parsed based on the
+*                 work calendar, then the result (milliseconds and time zone)
+*                 will be set in this calendar.
+* @param text The text to parse.
+* @param textLength The length of text, or -1 if null-terminated.
+* @param parsePos If not 0, on input a pointer to an integer specifying the offset at which
+* to begin parsing.  If not 0, on output the offset at which parsing ended.
+* @param status A pointer to an UErrorCode to receive any errors
+* @see udat_format
+* @stable ICU 2.0
+*/
+U_CAPI void U_EXPORT2
+udat_parseCalendar(const    UDateFormat*    format,
+                            UCalendar*      calendar,
+                   const    UChar*          text,
+                            int32_t         textLength,
+                            int32_t         *parsePos,
+                            UErrorCode      *status);
+
+/**
+* Determine if an UDateFormat will perform lenient parsing.
+* With lenient parsing, the parser may use heuristics to interpret inputs that do not
+* precisely match the pattern. With strict parsing, inputs must match the pattern.
+* @param fmt The formatter to query
+* @return true if fmt is set to perform lenient parsing, false otherwise.
+* @see udat_setLenient
+* @stable ICU 2.0
+*/
+U_CAPI UBool U_EXPORT2
+udat_isLenient(const UDateFormat* fmt);
+
+/**
+* Specify whether an UDateFormat will perform lenient parsing.
+* With lenient parsing, the parser may use heuristics to interpret inputs that do not
+* precisely match the pattern. With strict parsing, inputs must match the pattern.
+* @param fmt The formatter to set
+* @param isLenient true if fmt should perform lenient parsing, false otherwise.
+* @see dat_isLenient
+* @stable ICU 2.0
+*/
+U_CAPI void U_EXPORT2
+udat_setLenient(    UDateFormat*    fmt,
+                    UBool          isLenient);
+
+/**
+* Get the UCalendar associated with an UDateFormat.
+* A UDateFormat uses a UCalendar to convert a raw value to, for example,
+* the day of the week.
+* @param fmt The formatter to query.
+* @return A pointer to the UCalendar used by fmt.
+* @see udat_setCalendar
+* @stable ICU 2.0
+*/
+U_CAPI const UCalendar* U_EXPORT2
+udat_getCalendar(const UDateFormat* fmt);
+
+/**
+* Set the UCalendar associated with an UDateFormat.
+* A UDateFormat uses a UCalendar to convert a raw value to, for example,
+* the day of the week.
+* @param fmt The formatter to set.
+* @param calendarToSet A pointer to an UCalendar to be used by fmt.
+* @see udat_setCalendar
+* @stable ICU 2.0
+*/
+U_CAPI void U_EXPORT2
+udat_setCalendar(            UDateFormat*    fmt,
+                    const   UCalendar*      calendarToSet);
+
+/**
+* Get the UNumberFormat associated with an UDateFormat.
+* A UDateFormat uses a UNumberFormat to format numbers within a date,
+* for example the day number.
+* @param fmt The formatter to query.
+* @return A pointer to the UNumberFormat used by fmt to format numbers.
+* @see udat_setNumberFormat
+* @stable ICU 2.0
+*/
+U_CAPI const UNumberFormat* U_EXPORT2
+udat_getNumberFormat(const UDateFormat* fmt);
+
+/**
+* Get the UNumberFormat for specific field associated with an UDateFormat.
+* For example: 'y' for year and 'M' for month
+* @param fmt The formatter to query.
+* @param field the field to query
+* @return A pointer to the UNumberFormat used by fmt to format field numbers.
+* @see udat_setNumberFormatForField
+* @stable ICU 54
+*/
+U_CAPI const UNumberFormat* U_EXPORT2
+udat_getNumberFormatForField(const UDateFormat* fmt, UChar field);
+
+/**
+* Set the UNumberFormat for specific field associated with an UDateFormat.
+* It can be a single field like: "y"(year) or "M"(month)
+* It can be several field combined together: "yM"(year and month)
+* Note:
+* 1 symbol field is enough for multiple symbol field (so "y" will override "yy", "yyy")
+* If the field is not numeric, then override has no effect (like "MMM" will use abbreviation, not numerical field)
+*
+* @param fields the fields to set
+* @param fmt The formatter to set.
+* @param numberFormatToSet A pointer to the UNumberFormat to be used by fmt to format numbers.
+* @param status error code passed around (memory allocation or invalid fields)
+* @see udat_getNumberFormatForField
+* @stable ICU 54
+*/
+U_CAPI void U_EXPORT2
+udat_adoptNumberFormatForFields(  UDateFormat* fmt,
+                            const UChar* fields,
+                                  UNumberFormat*  numberFormatToSet,
+                                  UErrorCode* status);
+/**
+* Set the UNumberFormat associated with an UDateFormat.
+* A UDateFormat uses a UNumberFormat to format numbers within a date,
+* for example the day number.
+* This method also clears per field NumberFormat instances previously
+* set by {@see udat_setNumberFormatForField}
+* @param fmt The formatter to set.
+* @param numberFormatToSet A pointer to the UNumberFormat to be used by fmt to format numbers.
+* @see udat_getNumberFormat
+* @see udat_setNumberFormatForField
+* @stable ICU 2.0
+*/
+U_CAPI void U_EXPORT2
+udat_setNumberFormat(            UDateFormat*    fmt,
+                        const   UNumberFormat*  numberFormatToSet);
+/**
+* Adopt the UNumberFormat associated with an UDateFormat.
+* A UDateFormat uses a UNumberFormat to format numbers within a date,
+* for example the day number.
+* @param fmt The formatter to set.
+* @param numberFormatToAdopt A pointer to the UNumberFormat to be used by fmt to format numbers.
+* @see udat_getNumberFormat
+* @stable ICU 54
+*/
+U_CAPI void U_EXPORT2
+udat_adoptNumberFormat(            UDateFormat*    fmt,
+                                   UNumberFormat*  numberFormatToAdopt);
+/**
+* Get a locale for which date/time formatting patterns are available.
+* A UDateFormat in a locale returned by this function will perform the correct
+* formatting and parsing for the locale.
+* @param localeIndex The index of the desired locale.
+* @return A locale for which date/time formatting patterns are available, or 0 if none.
+* @see udat_countAvailable
+* @stable ICU 2.0
+*/
+U_CAPI const char* U_EXPORT2
+udat_getAvailable(int32_t localeIndex);
+
+/**
+* Determine how many locales have date/time  formatting patterns available.
+* This function is most useful as determining the loop ending condition for
+* calls to {@link #udat_getAvailable }.
+* @return The number of locales for which date/time formatting patterns are available.
+* @see udat_getAvailable
+* @stable ICU 2.0
+*/
+U_CAPI int32_t U_EXPORT2
+udat_countAvailable(void);
+
+/**
+* Get the year relative to which all 2-digit years are interpreted.
+* For example, if the 2-digit start year is 2100, the year 99 will be
+* interpreted as 2199.
+* @param fmt The formatter to query.
+* @param status A pointer to an UErrorCode to receive any errors
+* @return The year relative to which all 2-digit years are interpreted.
+* @see udat_Set2DigitYearStart
+* @stable ICU 2.0
+*/
+U_CAPI UDate U_EXPORT2
+udat_get2DigitYearStart(    const   UDateFormat     *fmt,
+                                    UErrorCode      *status);
+
+/**
+* Set the year relative to which all 2-digit years will be interpreted.
+* For example, if the 2-digit start year is 2100, the year 99 will be
+* interpreted as 2199.
+* @param fmt The formatter to set.
+* @param d The year relative to which all 2-digit years will be interpreted.
+* @param status A pointer to an UErrorCode to receive any errors
+* @see udat_Set2DigitYearStart
+* @stable ICU 2.0
+*/
+U_CAPI void U_EXPORT2
+udat_set2DigitYearStart(    UDateFormat     *fmt,
+                            UDate           d,
+                            UErrorCode      *status);
+
+/**
+* Extract the pattern from a UDateFormat.
+* The pattern will follow the pattern syntax rules.
+* @param fmt The formatter to query.
+* @param localized true if the pattern should be localized, false otherwise.
+* @param result A pointer to a buffer to receive the pattern.
+* @param resultLength The maximum size of result.
+* @param status A pointer to an UErrorCode to receive any errors
+* @return The total buffer size needed; if greater than resultLength, the output was truncated.
+* @see udat_applyPattern
+* @stable ICU 2.0
+*/
+U_CAPI int32_t U_EXPORT2
+udat_toPattern(    const   UDateFormat     *fmt,
+                        UBool          localized,
+                        UChar           *result,
+                        int32_t         resultLength,
+                        UErrorCode      *status);
+
+/**
+* Set the pattern used by an UDateFormat.
+* The pattern should follow the pattern syntax rules.
+* @param format The formatter to set.
+* @param localized true if the pattern is localized, false otherwise.
+* @param pattern The new pattern
+* @param patternLength The length of pattern, or -1 if null-terminated.
+* @see udat_toPattern
+* @stable ICU 2.0
+*/
+U_CAPI void U_EXPORT2
+udat_applyPattern(            UDateFormat     *format,
+                            UBool          localized,
+                    const   UChar           *pattern,
+                            int32_t         patternLength);
+
+/**
+ * The possible types of date format symbols
+ * @stable ICU 2.6
+ */
+typedef enum UDateFormatSymbolType {
+    /** The era names, for example AD */
+    UDAT_ERAS,
+    /** The month names, for example February */
+    UDAT_MONTHS,
+    /** The short month names, for example Feb. */
+    UDAT_SHORT_MONTHS,
+    /** The CLDR-style format "wide" weekday names, for example Monday */
+    UDAT_WEEKDAYS,
+    /**
+     * The CLDR-style format "abbreviated" (not "short") weekday names, for example "Mon."
+     * For the CLDR-style format "short" weekday names, use UDAT_SHORTER_WEEKDAYS.
+     */
+    UDAT_SHORT_WEEKDAYS,
+    /** The AM/PM names, for example AM */
+    UDAT_AM_PMS,
+    /** The localized characters */
+    UDAT_LOCALIZED_CHARS,
+    /** The long era names, for example Anno Domini */
+    UDAT_ERA_NAMES,
+    /** The narrow month names, for example F */
+    UDAT_NARROW_MONTHS,
+    /** The CLDR-style format "narrow" weekday names, for example "M" */
+    UDAT_NARROW_WEEKDAYS,
+    /** Standalone context versions of months */
+    UDAT_STANDALONE_MONTHS,
+    UDAT_STANDALONE_SHORT_MONTHS,
+    UDAT_STANDALONE_NARROW_MONTHS,
+    /** The CLDR-style stand-alone "wide" weekday names */
+    UDAT_STANDALONE_WEEKDAYS,
+    /**
+     * The CLDR-style stand-alone "abbreviated" (not "short") weekday names.
+     * For the CLDR-style stand-alone "short" weekday names, use UDAT_STANDALONE_SHORTER_WEEKDAYS.
+     */
+    UDAT_STANDALONE_SHORT_WEEKDAYS,
+    /** The CLDR-style stand-alone "narrow" weekday names */
+    UDAT_STANDALONE_NARROW_WEEKDAYS,
+    /** The quarters, for example 1st Quarter */
+    UDAT_QUARTERS,
+    /** The short quarter names, for example Q1 */
+    UDAT_SHORT_QUARTERS,
+    /** Standalone context versions of quarters */
+    UDAT_STANDALONE_QUARTERS,
+    UDAT_STANDALONE_SHORT_QUARTERS,
+    /**
+     * The CLDR-style short weekday names, e.g. "Su", Mo", etc.
+     * These are named "SHORTER" to contrast with the constants using _SHORT_
+     * above, which actually get the CLDR-style *abbreviated* versions of the
+     * corresponding names.
+     * @stable ICU 51
+     */
+    UDAT_SHORTER_WEEKDAYS,
+    /**
+     * Standalone version of UDAT_SHORTER_WEEKDAYS.
+     * @stable ICU 51
+     */
+    UDAT_STANDALONE_SHORTER_WEEKDAYS,
+    /**
+     * Cyclic year names (only supported for some calendars, and only for FORMAT usage;
+     * udat_setSymbols not supported for UDAT_CYCLIC_YEARS_WIDE)
+     * @stable ICU 54
+     */
+    UDAT_CYCLIC_YEARS_WIDE,
+    /**
+     * Cyclic year names (only supported for some calendars, and only for FORMAT usage)
+     * @stable ICU 54
+     */
+    UDAT_CYCLIC_YEARS_ABBREVIATED,
+    /**
+     * Cyclic year names (only supported for some calendars, and only for FORMAT usage;
+     * udat_setSymbols not supported for UDAT_CYCLIC_YEARS_NARROW)
+     * @stable ICU 54
+     */
+    UDAT_CYCLIC_YEARS_NARROW,
+    /**
+     * Calendar zodiac  names (only supported for some calendars, and only for FORMAT usage;
+     * udat_setSymbols not supported for UDAT_ZODIAC_NAMES_WIDE)
+     * @stable ICU 54
+     */
+    UDAT_ZODIAC_NAMES_WIDE,
+    /**
+     * Calendar zodiac  names (only supported for some calendars, and only for FORMAT usage)
+     * @stable ICU 54
+     */
+    UDAT_ZODIAC_NAMES_ABBREVIATED,
+    /**
+     * Calendar zodiac  names (only supported for some calendars, and only for FORMAT usage;
+     * udat_setSymbols not supported for UDAT_ZODIAC_NAMES_NARROW)
+     * @stable ICU 54
+     */
+    UDAT_ZODIAC_NAMES_NARROW,
+    
+    /**
+     * The narrow quarter names, for example 1
+     * @stable ICU 70
+     */
+    UDAT_NARROW_QUARTERS,
+    
+    /**
+     * The narrow standalone quarter names, for example 1
+     * @stable ICU 70
+     */
+    UDAT_STANDALONE_NARROW_QUARTERS
+} UDateFormatSymbolType;
+
+struct UDateFormatSymbols;
+/** Date format symbols.
+ *  For usage in C programs.
+ *  @stable ICU 2.6
+ */
+typedef struct UDateFormatSymbols UDateFormatSymbols;
+
+/**
+* Get the symbols associated with an UDateFormat.
+* The symbols are what a UDateFormat uses to represent locale-specific data,
+* for example month or day names.
+* @param fmt The formatter to query.
+* @param type The type of symbols to get.  One of UDAT_ERAS, UDAT_MONTHS, UDAT_SHORT_MONTHS,
+* UDAT_WEEKDAYS, UDAT_SHORT_WEEKDAYS, UDAT_AM_PMS, or UDAT_LOCALIZED_CHARS
+* @param symbolIndex The desired symbol of type type.
+* @param result A pointer to a buffer to receive the pattern.
+* @param resultLength The maximum size of result.
+* @param status A pointer to an UErrorCode to receive any errors
+* @return The total buffer size needed; if greater than resultLength, the output was truncated.
+* @see udat_countSymbols
+* @see udat_setSymbols
+* @stable ICU 2.0
+*/
+U_CAPI int32_t U_EXPORT2
+udat_getSymbols(const   UDateFormat             *fmt,
+                        UDateFormatSymbolType   type,
+                        int32_t                 symbolIndex,
+                        UChar                   *result,
+                        int32_t                 resultLength,
+                        UErrorCode              *status);
+
+/**
+* Count the number of particular symbols for an UDateFormat.
+* This function is most useful as for determining the loop termination condition
+* for calls to {@link #udat_getSymbols }.
+* @param fmt The formatter to query.
+* @param type The type of symbols to count.  One of UDAT_ERAS, UDAT_MONTHS, UDAT_SHORT_MONTHS,
+* UDAT_WEEKDAYS, UDAT_SHORT_WEEKDAYS, UDAT_AM_PMS, or UDAT_LOCALIZED_CHARS
+* @return The number of symbols of type type.
+* @see udat_getSymbols
+* @see udat_setSymbols
+* @stable ICU 2.0
+*/
+U_CAPI int32_t U_EXPORT2
+udat_countSymbols(    const    UDateFormat                *fmt,
+                            UDateFormatSymbolType    type);
+
+/**
+* Set the symbols associated with an UDateFormat.
+* The symbols are what a UDateFormat uses to represent locale-specific data,
+* for example month or day names.
+* @param format The formatter to set
+* @param type The type of symbols to set.  One of UDAT_ERAS, UDAT_MONTHS, UDAT_SHORT_MONTHS,
+* UDAT_WEEKDAYS, UDAT_SHORT_WEEKDAYS, UDAT_AM_PMS, or UDAT_LOCALIZED_CHARS
+* @param symbolIndex The index of the symbol to set of type type.
+* @param value The new value
+* @param valueLength The length of value, or -1 if null-terminated
+* @param status A pointer to an UErrorCode to receive any errors
+* @see udat_getSymbols
+* @see udat_countSymbols
+* @stable ICU 2.0
+*/
+U_CAPI void U_EXPORT2
+udat_setSymbols(    UDateFormat             *format,
+                    UDateFormatSymbolType   type,
+                    int32_t                 symbolIndex,
+                    UChar                   *value,
+                    int32_t                 valueLength,
+                    UErrorCode              *status);
+
+/**
+ * Get the locale for this date format object.
+ * You can choose between valid and actual locale.
+ * @param fmt The formatter to get the locale from
+ * @param type type of the locale we're looking for (valid or actual)
+ * @param status error code for the operation
+ * @return the locale name
+ * @stable ICU 2.8
+ */
+U_CAPI const char* U_EXPORT2
+udat_getLocaleByType(const UDateFormat *fmt,
+                     ULocDataLocaleType type,
+                     UErrorCode* status);
+
+/**
+ * Set a particular UDisplayContext value in the formatter, such as
+ * UDISPCTX_CAPITALIZATION_FOR_STANDALONE.
+ * @param fmt The formatter for which to set a UDisplayContext value.
+ * @param value The UDisplayContext value to set.
+ * @param status A pointer to an UErrorCode to receive any errors
+ * @stable ICU 51
+ */
+U_CAPI void U_EXPORT2
+udat_setContext(UDateFormat* fmt, UDisplayContext value, UErrorCode* status);
+
+/**
+ * Get the formatter's UDisplayContext value for the specified UDisplayContextType,
+ * such as UDISPCTX_TYPE_CAPITALIZATION.
+ * @param fmt The formatter to query.
+ * @param type The UDisplayContextType whose value to return
+ * @param status A pointer to an UErrorCode to receive any errors
+ * @return The UDisplayContextValue for the specified type.
+ * @stable ICU 53
+ */
+U_CAPI UDisplayContext U_EXPORT2
+udat_getContext(const UDateFormat* fmt, UDisplayContextType type, UErrorCode* status);
+
+#ifndef U_HIDE_INTERNAL_API
+/**
+* Extract the date pattern from a UDateFormat set for relative date formatting.
+* The pattern will follow the pattern syntax rules.
+* @param fmt The formatter to query.
+* @param result A pointer to a buffer to receive the pattern.
+* @param resultLength The maximum size of result.
+* @param status A pointer to a UErrorCode to receive any errors
+* @return The total buffer size needed; if greater than resultLength, the output was truncated.
+* @see udat_applyPatternRelative
+* @internal ICU 4.2 technology preview
+*/
+U_CAPI int32_t U_EXPORT2
+udat_toPatternRelativeDate(const UDateFormat *fmt,
+                           UChar             *result,
+                           int32_t           resultLength,
+                           UErrorCode        *status);
+
+/**
+* Extract the time pattern from a UDateFormat set for relative date formatting.
+* The pattern will follow the pattern syntax rules.
+* @param fmt The formatter to query.
+* @param result A pointer to a buffer to receive the pattern.
+* @param resultLength The maximum size of result.
+* @param status A pointer to a UErrorCode to receive any errors
+* @return The total buffer size needed; if greater than resultLength, the output was truncated.
+* @see udat_applyPatternRelative
+* @internal ICU 4.2 technology preview
+*/
+U_CAPI int32_t U_EXPORT2
+udat_toPatternRelativeTime(const UDateFormat *fmt,
+                           UChar             *result,
+                           int32_t           resultLength,
+                           UErrorCode        *status);
+
+/**
+* Set the date & time patterns used by a UDateFormat set for relative date formatting.
+* The patterns should follow the pattern syntax rules.
+* @param format The formatter to set.
+* @param datePattern The new date pattern
+* @param datePatternLength The length of datePattern, or -1 if null-terminated.
+* @param timePattern The new time pattern
+* @param timePatternLength The length of timePattern, or -1 if null-terminated.
+* @param status A pointer to a UErrorCode to receive any errors
+* @see udat_toPatternRelativeDate, udat_toPatternRelativeTime
+* @internal ICU 4.2 technology preview
+*/
+U_CAPI void U_EXPORT2
+udat_applyPatternRelative(UDateFormat *format,
+                          const UChar *datePattern,
+                          int32_t     datePatternLength,
+                          const UChar *timePattern,
+                          int32_t     timePatternLength,
+                          UErrorCode  *status);
+
+/**
+ * @internal
+ * @see udat_open
+ */
+typedef UDateFormat* (U_EXPORT2 *UDateFormatOpener) (UDateFormatStyle  timeStyle,
+                                                    UDateFormatStyle  dateStyle,
+                                                    const char        *locale,
+                                                    const UChar       *tzID,
+                                                    int32_t           tzIDLength,
+                                                    const UChar       *pattern,
+                                                    int32_t           patternLength,
+                                                    UErrorCode        *status);
+
+/**
+ * Register a provider factory
+ * @internal ICU 49
+ */
+U_CAPI void U_EXPORT2
+udat_registerOpener(UDateFormatOpener opener, UErrorCode *status);
+
+/**
+ * Un-Register a provider factory
+ * @internal ICU 49
+ */
+U_CAPI UDateFormatOpener U_EXPORT2
+udat_unregisterOpener(UDateFormatOpener opener, UErrorCode *status);
+#endif  /* U_HIDE_INTERNAL_API */
+
+
+#endif /* #if !UCONFIG_NO_FORMATTING */
+
+#endif