/*
 * $Id: time_asctime_r.c,v 1.7 2005-02-25 10:14:21 obarthel Exp $
 *
 * :ts=4
 *
 * Portable ISO 'C' (1994) runtime library for the Amiga computer
 * Copyright (c) 2002-2005 by Olaf Barthel <olsen@sourcery.han.de>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Neither the name of Olaf Barthel nor the names of 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.
 */

#ifndef _STDLIB_NULL_POINTER_CHECK_H
#include "stdlib_null_pointer_check.h"
#endif /* _STDLIB_NULL_POINTER_CHECK_H */

/****************************************************************************/

#ifndef _TIME_HEADERS_H
#include "time_headers.h"
#endif /* _TIME_HEADERS_H */

/****************************************************************************/

STATIC VOID
add_to_string(char * to,size_t to_size,const char * string,size_t * offset_ptr)
{
	size_t offset,len;

	assert( to != NULL && to_size > 0 && string != NULL && offset_ptr != NULL );

	offset = (*offset_ptr);

	assert( offset < to_size );

	len = strlen(string);
	if(offset + len > to_size)
		len = to_size - offset;

	if(len > 0)
	{
		memmove(&to[offset],string,len);

		offset += len;

		(*offset_ptr) = offset;
	}
}

/****************************************************************************/

char *
__asctime_r(const struct tm *tm,char * buffer,size_t buffer_size)
{
	char * result = NULL;

	ENTER();

	SHOWPOINTER(tm);

	assert( tm != NULL || buffer == NULL );

	#if defined(CHECK_FOR_NULL_POINTERS)
	{
		if(tm == NULL || buffer == NULL )
		{
			__set_errno(EFAULT);
			goto out;
		}
	}
	#endif /* CHECK_FOR_NULL_POINTERS */

	if(buffer_size > 0)
	{
		struct tm copy_tm;
		char number[16];
		const char * b;
		size_t offset = 0;

		buffer_size--;

		/* Fill in the week day if it's not in proper range. */
		if(tm->tm_wday < 0 || tm->tm_wday > 6)
		{
			/* We use a peculiar algorithm rather than falling back onto
			   mktime() here in order to avoid trouble with skewed results
			   owing to time zone influence. */
			copy_tm = (*tm);
			copy_tm.tm_wday = __calculate_weekday(tm->tm_year+1900,tm->tm_mon+1,tm->tm_mday);

			tm = &copy_tm;
		}

		assert( 0 <= tm->tm_wday && tm->tm_wday <= 6 );

		b = __abbreviated_week_day_names[tm->tm_wday];

		add_to_string(buffer,buffer_size,b,		&offset);
		add_to_string(buffer,buffer_size," ",	&offset);

		if(0 <= tm->tm_mon && tm->tm_mon <= 11)
			b = __abbreviated_month_names[tm->tm_mon];
		else
			b = "---";

		add_to_string(buffer,buffer_size,b,		&offset);
		add_to_string(buffer,buffer_size," ",	&offset);

		if(1 <= tm->tm_mday && tm->tm_mday <= 31)
			b = __number_to_string((unsigned int)tm->tm_mday,number,sizeof(number),2);
		else
			b = "--";

		add_to_string(buffer,buffer_size,b,		&offset);
		add_to_string(buffer,buffer_size," ",	&offset);

		if(0 <= tm->tm_hour && tm->tm_hour <= 23)
			b = __number_to_string((unsigned int)tm->tm_hour,number,sizeof(number),2);
		else
			b = "--";

		add_to_string(buffer,buffer_size,b,		&offset);
		add_to_string(buffer,buffer_size,":",	&offset);

		if(0 <= tm->tm_min && tm->tm_min <= 59)
			b = __number_to_string((unsigned int)tm->tm_min,number,sizeof(number),2);
		else
			b = "--";

		add_to_string(buffer,buffer_size,b,		&offset);
		add_to_string(buffer,buffer_size,":",	&offset);

		if(0 <= tm->tm_sec && tm->tm_sec <= 59)
			b = __number_to_string((unsigned int)tm->tm_sec,number,sizeof(number),2);
		else
			b = "--";

		add_to_string(buffer,buffer_size,b,		&offset);
		add_to_string(buffer,buffer_size," ",	&offset);

		if(0 <= tm->tm_year)
			b = __number_to_string((unsigned int)1900 + tm->tm_year,number,sizeof(number),0);
		else
			b = "----";

		add_to_string(buffer,buffer_size,b,&offset);

		SHOWSTRING(buffer);

		add_to_string(buffer,buffer_size,"\n",&offset);

		assert( offset <= buffer_size );
		buffer[offset] = '\0';

		result = buffer;
	}
	else
	{
		result = "";
	}

 out:

	RETURN(result);
	return(result);
}

/****************************************************************************/

char *
asctime_r(const struct tm *tm,char * buffer)
{
	char * result;

	ENTER();

	result = __asctime_r(tm,buffer,40);

	RETURN(result);
	return(result);
}
