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udat.h File Reference

C API: DateFormat. More...

#include "unicode/utypes.h"
#include "unicode/ucal.h"
#include "unicode/unum.h"

Go to the source code of this file.

Typedefs

typedef void * UDateFormat
 A date formatter.
typedef enum UDateFormatStyle UDateFormatStyle
typedef enum UDateFormatSymbolType UDateFormatSymbolType
typedef UDateFormatSymbols UDateFormatSymbols

Enumerations

enum  UDateFormatStyle {
  UDAT_FULL, UDAT_LONG, UDAT_MEDIUM, UDAT_SHORT,
  UDAT_DEFAULT = UDAT_MEDIUM, UDAT_NONE = -1, UDAT_IGNORE = -2
}
 The possible date/time format styles. More...
enum  UDateFormatSymbolType {
  UDAT_ERAS, UDAT_MONTHS, UDAT_SHORT_MONTHS, UDAT_WEEKDAYS,
  UDAT_SHORT_WEEKDAYS, UDAT_AM_PMS, UDAT_LOCALIZED_CHARS
}
 The possible types of date format symbols. More...

Functions

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)
 Open a new UDateFormat for formatting and parsing dates and times.
U_CAPI void U_EXPORT2 udat_close (UDateFormat *format)
 Close a UDateFormat.
U_CAPI UDateFormat *U_EXPORT2 udat_clone (const UDateFormat *fmt, UErrorCode *status)
 Open a copy of a UDateFormat.
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.
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.
U_CAPI void U_EXPORT2 udat_parseCalendar (const UDateFormat *format, UCalendar *calendar, const UChar *text, int32_t textLength, int32_t *parsePos, UErrorCode *status)
 Parse a string into an date/time using a UDateFormat.
U_CAPI UBool U_EXPORT2 udat_isLenient (const UDateFormat *fmt)
 Determine if an UDateFormat will perform lenient parsing.
U_CAPI void U_EXPORT2 udat_setLenient (UDateFormat *fmt, UBool isLenient)
 Specify whether an UDateFormat will perform lenient parsing.
U_CAPI const UCalendar *U_EXPORT2 udat_getCalendar (const UDateFormat *fmt)
 Get the UCalendar associated with an UDateFormat.
U_CAPI void U_EXPORT2 udat_setCalendar (UDateFormat *fmt, const UCalendar *calendarToSet)
 Set the UCalendar associated with an UDateFormat.
U_CAPI const UNumberFormat
*U_EXPORT2 
udat_getNumberFormat (const UDateFormat *fmt)
 Get the UNumberFormat associated with an UDateFormat.
U_CAPI void U_EXPORT2 udat_setNumberFormat (UDateFormat *fmt, const UNumberFormat *numberFormatToSet)
 Set the UNumberFormat associated with an UDateFormat.
U_CAPI const char *U_EXPORT2 udat_getAvailable (int32_t index)
 Get a locale for which date/time formatting patterns are available.
U_CAPI int32_t U_EXPORT2 udat_countAvailable (void)
 Determine how many locales have date/time formatting patterns available.
U_CAPI UDate U_EXPORT2 udat_get2DigitYearStart (const UDateFormat *fmt, UErrorCode *status)
 Get the year relative to which all 2-digit years are interpreted.
U_CAPI void U_EXPORT2 udat_set2DigitYearStart (UDateFormat *fmt, UDate d, UErrorCode *status)
 Set the year relative to which all 2-digit years will be interpreted.
U_CAPI int32_t U_EXPORT2 udat_toPattern (const UDateFormat *fmt, UBool localized, UChar *result, int32_t resultLength, UErrorCode *status)
 Extract the pattern from a UDateFormat.
U_CAPI void U_EXPORT2 udat_applyPattern (UDateFormat *format, UBool localized, const UChar *pattern, int32_t patternLength)
 Set the pattern used by an UDateFormat.
U_CAPI int32_t U_EXPORT2 udat_getSymbols (const UDateFormat *fmt, UDateFormatSymbolType type, int32_t index, UChar *result, int32_t resultLength, UErrorCode *status)
 Get the symbols associated with an UDateFormat.
U_CAPI int32_t U_EXPORT2 udat_countSymbols (const UDateFormat *fmt, UDateFormatSymbolType type)
 Count the number of particular symbols for an UDateFormat.
U_CAPI void U_EXPORT2 udat_setSymbols (UDateFormat *format, UDateFormatSymbolType type, int32_t index, UChar *value, int32_t valueLength, UErrorCode *status)
 Set the symbols associated with an UDateFormat.


Detailed Description

C API: DateFormat.

Date Format C API

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.

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.

To format a date for the current Locale with default time and date style, use one of the static factory methods:

  UErrorCode status = U_ZERO_ERROR;
  UChar *myString;
  int32_t myStrlen = 0;
  UDateFormat* dfmt = udat_open(UCAL_DEFAULT, UCAL_DEFAULT, NULL, "PST", &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);
  }
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.
  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(UCAL_DEFAULT, UCAL_DEFAULT, NULL, "GMT", &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);
      }
  }
To get specific fields of a date, you can use UFieldPosition to get specific fields.
  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(UCAL_DEFAULT, UCAL_DEFAULT, NULL, "PST", &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]);
To format a date for a different Locale, specify it in the call to udat_open()
        UDateFormat* df = udat_open(UDAT_SHORT, UDAT_SHORT, "fr_FR", "GMT", &status);
You can use a DateFormat API udat_parse() to parse.
  UErrorCode status = U_ZERO_ERROR;
  int32_t parsepos=0;
  UDate myDate = udat_parse(df, myString, u_strlen(myString), &parsepos, &status);
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 You can also set the time zone on the format if you wish.

You can also use forms of the parse and format methods with Parse Position and UFieldPosition to allow you to


Typedef Documentation

typedef void* UDateFormat
 

A date formatter.

For usage in C programs.


Enumeration Type Documentation

enum UDateFormatStyle
 

The possible date/time format styles.

Enumerator:
UDAT_FULL  Full style.
UDAT_LONG  Long style.
UDAT_MEDIUM  Medium style.
UDAT_SHORT  Short style.
UDAT_DEFAULT  Default style.
UDAT_NONE  No style.
UDAT_IGNORE  for internal API use only

enum UDateFormatSymbolType
 

The possible types of date format symbols.

Enumerator:
UDAT_ERAS  The era names, for example AD.
UDAT_MONTHS  The month names, for example February.
UDAT_SHORT_MONTHS  The short month names, for example Feb.
UDAT_WEEKDAYS  The weekday names, for example Monday.
UDAT_SHORT_WEEKDAYS  The short weekday names, for example Mon.
UDAT_AM_PMS  The AM/PM names, for example AM.
UDAT_LOCALIZED_CHARS  The localized characters.


Function Documentation

U_CAPI void U_EXPORT2 udat_applyPattern UDateFormat format,
UBool  localized,
const UChar pattern,
int32_t  patternLength
 

Set the pattern used by an UDateFormat.

The pattern should follow the pattern syntax rules.

Parameters:
fmt The formatter to set.
localized TRUE if the pattern is localized, FALSE otherwise.
pattern The new pattern
patternLength The length of pattern, or -1 if null-terminated.
See also:
udat_toPattern

U_CAPI UDateFormat* U_EXPORT2 udat_clone const UDateFormat fmt,
UErrorCode status
 

Open a copy of a UDateFormat.

This function performs a deep copy.

Parameters:
fmt The format to copy
status A pointer to an UErrorCode to receive any errors.
Returns:
A pointer to a UDateFormat identical to fmt.

U_CAPI void U_EXPORT2 udat_close UDateFormat format  ) 
 

Close a UDateFormat.

Once closed, a UDateFormat may no longer be used.

Parameters:
fmt The formatter to close.

U_CAPI int32_t U_EXPORT2 udat_countAvailable void   ) 
 

Determine how many locales have date/time formatting patterns available.

This function is most useful as determining the loop ending condition for calls to {udat_getAvailable}.

Returns:
The number of locales for which date/time formatting patterns are available.
See also:
udat_getAvailable

U_CAPI int32_t U_EXPORT2 udat_countSymbols const UDateFormat fmt,
UDateFormatSymbolType  type
 

Count the number of particular symbols for an UDateFormat.

This function is most useful as for detemining the loop termination condition for calls to {udat_getSymbols}.

Parameters:
fmt The formatter to query.
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
Returns:
The number of symbols of type type.
See also:
udat_getSymbols

udat_setSymbols

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 {udat_open} or {udat_openPattern}

Parameters:
format The formatter to use
dateToFormat The date to format
result A pointer to a buffer to receive the formatted number.
resultLength The maximum size of result.
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.
status A pointer to an UErrorCode to receive any errors
Returns:
The total buffer size needed; if greater than resultLength, the output was truncated.
See also:
udat_parse

UFieldPosition

U_CAPI UDate U_EXPORT2 udat_get2DigitYearStart const UDateFormat fmt,
UErrorCode status
 

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.

Parameters:
fmt The formatter to query.
status A pointer to an UErrorCode to receive any errors
Returns:
The year relative to which all 2-digit years are interpreted.
See also:
udat_Set2DigitYearStart

U_CAPI const char* U_EXPORT2 udat_getAvailable int32_t  index  ) 
 

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.

Parameters:
index The index of the desired locale.
Returns:
A locale for which date/time formatting patterns are available, or 0 if none.
See also:
udat_countAvailable

U_CAPI const UCalendar* U_EXPORT2 udat_getCalendar const UDateFormat fmt  ) 
 

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.

Parameters:
fmt The formatter to query.
Returns:
A pointer to the UCalendar used by fmt.
See also:
udat_setCalendar

U_CAPI const UNumberFormat* U_EXPORT2 udat_getNumberFormat const UDateFormat fmt  ) 
 

Get the UNumberFormat associated with an UDateFormat.

A UDateFormat uses a UNumberFormat to format numbers within a date, for example the day number.

Parameters:
fmt The formatter to query.
Returns:
A pointer to the UNumberFormat used by fmt to format numbers.
See also:
udat_setNumberFormat

U_CAPI int32_t U_EXPORT2 udat_getSymbols const UDateFormat fmt,
UDateFormatSymbolType  type,
int32_t  index,
UChar result,
int32_t  resultLength,
UErrorCode status
 

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.

Parameters:
fmt The formatter to query.
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
index The desired symbol of type type.
result A pointer to a buffer to receive the pattern.
resultLength The maximum size of result.
status A pointer to an UErrorCode to receive any errors
Returns:
The total buffer size needed; if greater than resultLength, the output was truncated.
See also:
udat_countSymbols

udat_setSymbols

U_CAPI UBool U_EXPORT2 udat_isLenient const UDateFormat fmt  ) 
 

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.

Parameters:
fmt The formatter to query
Returns:
TRUE if fmt is set to perform lenient parsing, FALSE otherwise.
See also:
udat_setLenient

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
 

Open a new UDateFormat for formatting and parsing dates and times.

A UDateFormat may be used to format dates in calls to {udat_format}, and to parse dates in calls to {udat_parse}.

Parameters:
timeStyle The style used to format times; one of UDAT_FULL_STYLE, UDAT_LONG_STYLE, UDAT_MEDIUM_STYLE, UDAT_SHORT_STYLE, or UDAT_DEFAULT_STYLE
dateStyle The style used to format dates; one of UDAT_FULL_STYLE, UDAT_LONG_STYLE, UDAT_MEDIUM_STYLE, UDAT_SHORT_STYLE, or UDAT_DEFAULT_STYLE
locale The locale specifying the formatting conventions
tzID A timezone ID specifying the timezone to use. If 0, use the default timezone.
tzIDLength The length of tzID, or -1 if null-terminated.
status A pointer to an UErrorCode to receive any errors
pattern A pattern specifying the format to use.
patternLength The number of characters in the pattern, or -1 if null-terminated.
locale The locale specifying the formatting conventions
status A pointer to an UErrorCode to receive any errors
Returns:
A pointer to a UDateFormat to use for formatting dates and times, or 0 if an error occurred.

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 {udat_open} or {udat_openPattern}

Parameters:
fmt The formatter to use.
text The text to parse.
textLength The length of text, or -1 if null-terminated.
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.
status A pointer to an UErrorCode to receive any errors
Returns:
The value of the parsed date/time
See also:
udat_format

U_CAPI void U_EXPORT2 udat_parseCalendar const UDateFormat format,
UCalendar calendar,
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 {udat_open} or {udat_openPattern}

Parameters:
fmt The formatter to use.
calendar The calendar in which to store the parsed data.
text The text to parse.
textLength The length of text, or -1 if null-terminated.
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.
status A pointer to an UErrorCode to receive any errors
See also:
udat_format

U_CAPI void U_EXPORT2 udat_set2DigitYearStart UDateFormat fmt,
UDate  d,
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.

Parameters:
fmt The formatter to set.
d The year relative to which all 2-digit years will be interpreted.
status A pointer to an UErrorCode to receive any errors
See also:
udat_Set2DigitYearStart

U_CAPI void U_EXPORT2 udat_setCalendar UDateFormat fmt,
const UCalendar calendarToSet
 

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.

Parameters:
fmt The formatter to set.
calendarToSet A pointer to an UCalendar to be used by fmt.
See also:
udat_setCalendar

U_CAPI void U_EXPORT2 udat_setLenient UDateFormat fmt,
UBool  isLenient
 

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.

Parameters:
fmt The formatter to set
isLenient TRUE if fmt should perform lenient parsing, FALSE otherwise.
See also:
dat_isLenient

U_CAPI void U_EXPORT2 udat_setNumberFormat UDateFormat fmt,
const UNumberFormat numberFormatToSet
 

Set the UNumberFormat associated with an UDateFormat.

A UDateFormat uses a UNumberFormat to format numbers within a date, for example the day number.

Parameters:
fmt The formatter to set.
numberFormatToSet A pointer to the UNumberFormat to be used by fmt to format numbers.
See also:
udat_getNumberFormat

U_CAPI void U_EXPORT2 udat_setSymbols UDateFormat format,
UDateFormatSymbolType  type,
int32_t  index,
UChar value,
int32_t  valueLength,
UErrorCode status
 

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.

Parameters:
fmt The formatter to set
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
index The index of the symbol to set of type type.
value The new value
valueLength The length of value, or -1 if null-terminated
status A pointer to an UErrorCode to receive any errors
See also:
udat_getSymbols

udat_countSymbols

U_CAPI int32_t U_EXPORT2 udat_toPattern const UDateFormat fmt,
UBool  localized,
UChar result,
int32_t  resultLength,
UErrorCode status
 

Extract the pattern from a UDateFormat.

The pattern will follow the pattern syntax rules.

Parameters:
fmt The formatter to query.
localized TRUE if the pattern should be localized, FALSE otherwise.
result A pointer to a buffer to receive the pattern.
resultLength The maximum size of result.
status A pointer to an UErrorCode to receive any errors
Returns:
The total buffer size needed; if greater than resultLength, the output was truncated.
See also:
udat_applyPattern


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