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incubator-nuttx/libc/time/lib_strftime.c

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/****************************************************************************
* libc/time/lib_strftime.c
*
* Copyright (C) 2009, 2011, 2013 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdio.h>
#include <time.h>
#include <debug.h>
#include <nuttx/time.h>
/****************************************************************************
* Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Public Constant Data
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
static const char * const g_abbrevmonthname[12] =
{
"Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
};
static const char * const g_monthname[12] =
{
"January", "February", "March", "April", "May", "June",
"July", "August", "September", "October", "November", "December"
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Function: strftime
*
* Description:
* The strftime() function formats the broken-down time tm according to
* the format specification format and places the result in the character
* array s of size max.
*
* Ordinary characters placed in the format string are copied to s without
* conversion. Conversion specifications are introduced by a '%' charac-
* ter, and terminated by a conversion specifier character, and are
* replaced in s as follows:
*
* %b The abbreviated month name according to the current locale.
* %B The full month name according to the current locale.
* %C The century number (year/100) as a 2-digit integer. (SU)
* %d The day of the month as a decimal number (range 01 to 31).
* %e Like %d, the day of the month as a decimal number, but a leading
* zero is replaced by a space.
* %h Equivalent to %b. (SU)
* %H The hour as a decimal number using a 24-hour clock (range 00 to 23).
* %I The hour as a decimal number using a 12-hour clock (range 01 to 12).
* %j The day of the year as a decimal number (range 001 to 366).
* %k The hour (24-hour clock) as a decimal number (range 0 to 23);
* single digits are preceded by a blank. (See also %H.) (TZ)
* %l The hour (12-hour clock) as a decimal number (range 1 to 12);
* single digits are preceded by a blank. (See also %I.) (TZ)
* %m The month as a decimal number (range 01 to 12).
* %M The minute as a decimal number (range 00 to 59).
* %n A newline character. (SU)
* %p Either "AM" or "PM" according to the given time value, or the
* corresponding strings for the current locale. Noon is treated
* as "PM" and midnight as "AM".
* %P Like %p but in lowercase: "am" or "pm" or a corresponding string
* for the current locale. (GNU)
* %s The number of seconds since the Epoch, that is, since 1970-01-01
* 00:00:00 UTC. (TZ)
* %S The second as a decimal number (range 00 to 60). (The range is
* up to 60 to allow for occasional leap seconds.)
* %t A tab character. (SU)
* %y The year as a decimal number without a century (range 00 to 99).
* %Y The year as a decimal number including the century.
* %% A literal '%' character.
*
* Returned Value:
* The strftime() function returns the number of characters placed in the
* array s, not including the terminating null byte, provided the string,
* including the terminating null byte, fits. Otherwise, it returns 0,
* and the contents of the array is undefined.
*
****************************************************************************/
size_t strftime(char *s, size_t max, const char *format, const struct tm *tm)
{
const char *str;
char *dest = s;
int chleft = max;
int value;
int len;
while (*format && chleft > 0)
{
/* Just copy regular characters */
if (*format != '%')
{
*dest++ = *format++;
chleft--;
continue;
}
/* Handle the format character */
format++;
len = 0;
switch (*format++)
{
/* %a: A three-letter abbreviation for the day of the week. */
/* %A: The full name for the day of the week. */
case 'a':
case 'A':
{
len = snprintf(dest, chleft, "Day"); /* Not supported */
}
break;
/* %h: Equivalent to %b */
case 'h':
/* %b: The abbreviated month name according to the current locale. */
case 'b':
{
if (tm->tm_mon < 12)
{
str = g_abbrevmonthname[tm->tm_mon];
len = snprintf(dest, chleft, "%s", str);
}
}
break;
/* %B: The full month name according to the current locale. */
case 'B':
{
if (tm->tm_mon < 12)
{
str = g_monthname[tm->tm_mon];
len = snprintf(dest, chleft, "%s", str);
}
}
break;
/* %y: The year as a decimal number without a century (range 00 to 99). */
case 'y':
/* %C: The century number (year/100) as a 2-digit integer. */
case 'C':
{
len = snprintf(dest, chleft, "%02d", tm->tm_year % 100);
}
break;
/* %d: The day of the month as a decimal number (range 01 to 31). */
case 'd':
{
len = snprintf(dest, chleft, "%02d", tm->tm_mday);
}
break;
/* %e: Like %d, the day of the month as a decimal number, but a leading
* zero is replaced by a space.
*/
case 'e':
{
len = snprintf(dest, chleft, "%2d", tm->tm_mday);
}
break;
/* %H: The hour as a decimal number using a 24-hour clock (range 00 to 23). */
case 'H':
{
len = snprintf(dest, chleft, "%02d", tm->tm_hour);
}
break;
/* %I: The hour as a decimal number using a 12-hour clock (range 01 to 12). */
case 'I':
{
len = snprintf(dest, chleft, "%02d", tm->tm_hour % 12);
}
break;
/* %j: The day of the year as a decimal number (range 001 to 366). */
case 'j':
{
if (tm->tm_mon < 12)
{
value = clock_daysbeforemonth(tm->tm_mon, clock_isleapyear(tm->tm_year)) + tm->tm_mday;
len = snprintf(dest, chleft, "%03d", value);
}
}
break;
/* %k: The hour (24-hour clock) as a decimal number (range 0 to 23);
* single digits are preceded by a blank.
*/
case 'k':
{
len = snprintf(dest, chleft, "%2d", tm->tm_hour);
}
break;
/* %l: The hour (12-hour clock) as a decimal number (range 1 to 12);
* single digits are preceded by a blank.
*/
case 'l':
{
len = snprintf(dest, chleft, "%2d", tm->tm_hour % 12);
}
break;
/* %m: The month as a decimal number (range 01 to 12). */
case 'm':
{
len = snprintf(dest, chleft, "%02d", tm->tm_mon + 1);
}
break;
/* %M: The minute as a decimal number (range 00 to 59). */
case 'M':
{
len = snprintf(dest, chleft, "%02d", tm->tm_min);
}
break;
/* %n: A newline character. */
case 'n':
{
*dest = '\n';
len = 1;
}
break;
/* %p: Either "AM" or "PM" according to the given time value. */
case 'p':
{
if (tm->tm_hour >= 12)
{
str = "PM";
}
else
{
str = "AM";
}
len = snprintf(dest, chleft, "%s", str);
}
break;
/* %P: Like %p but in lowercase: "am" or "pm" */
case 'P':
{
if (tm->tm_hour >= 12)
{
str = "pm";
}
else
{
str = "am";
}
len = snprintf(dest, chleft, "%s", str);
}
break;
/* %s: The number of seconds since the Epoch, that is, since 1970-01-01
* 00:00:00 UTC.
*/
case 's':
{
len = snprintf(dest, chleft, "%d", mktime(tm));
}
break;
/* %S: The second as a decimal number (range 00 to 60). (The range is
* up to 60 to allow for occasional leap seconds.)
*/
case 'S':
{
len = snprintf(dest, chleft, "%02d", tm->tm_sec);
}
break;
/* %t: A tab character. */
case 't':
{
*dest = '\t';
len = 1;
}
break;
/* %Y: The year as a decimal number including the century. */
case 'Y':
{
len = snprintf(dest, chleft, "%04d", tm->tm_year + 1900);
}
break;
/* %%: A literal '%' character. */
case '%':
{
*dest = '%';
len = 1;
}
break;
}
/* Update counts and pointers */
dest += len;
chleft -= len;
}
/* We get here because either we have reached the end of the format string
* or because there is no more space in the user-provided buffer and the
* resulting string has been truncated.
*
* Is there space remaining in the user-provided buffer for the NUL
* terminator?
*/
if (chleft > 0)
{
/* Yes, append terminating NUL byte */
*dest = '\0';
/* And return the number of bytes in the resulting string (excluding
* the NUL terminator).
*/
return max - chleft;
}
/* The string was truncated and/or not properly terminated. Return
* zero.
*/
return 0;
}
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