Date format converter－藍色情懷

Date format converter
/*
 * dtconfig.c
 *
 * Created by Jackie Xie on 2012-02-09.
 * Copyright 2011 Jackie Xie. All rights reserved.
 *
 */

#include <ctype.h>
#include <errno.h>
#include <getopt.h>
#include <math.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <time.h>
#include <sys/time.h>

/* ======================(function header)========================
Function Name: char *GetStrBetweenStr(char *,
 char *,char *)
Description: retrieve a string from between left position
 and right position string.
Arguments:char *s,char *lstr,char *rstr
Return: string
written by jackie xie
Date: 2007/07/10
================================================================*/
char *GetStrBetweenStr(char *s,char *lstr,char *rstr)
{
   char *p=s,*lp=s,*rp;
   do
   {
      /*trim(lstr);
 trim(rstr);*/
      lp=strstr(lp,lstr);
      if(lp)
      {
         rp=lstr;
         do lp++; while(*rp++);
         lp--;
         rp=strstr(lp,rstr);
         if(rp)
         {
            if(lp!=rp)
            {
               do *p++=*lp++; while(lp<rp);
               lp--;
            }
            rp=rstr;
            do lp++; while(*rp++);
            lp--;
         }
      }
   } while(lp);
   *p=0;
   return s;
}

/* ======================(function header)========================
Function Name: int matchStrPosAt (const char *, const char *)
Description: find the sub-string from the source string.
Arguments: const char *, const char *
Return: Returns "the array element number"(or "position") where 
 "sub-string" matches before in "original string", or return 
 "-1" if substr is not present in "original string".
written by jackie xie
Date : 2007/07/10
================================================================*/
/* 
 * delimiters <= n：return position before n-th matched substr.
 * delimiters = 0：do nothing.
 * delimiters >= n：return position after n-th matched substr.
 */
int matchStrPosAt (char * substr, char * str, int delimiters)
{
	int i = -1, k, str_index, total = 0;
	int substr_len = strlen(substr), str_len = strlen(str);
	int matchpos = -1;
	int delimiter[str_len], ind_delim = 0;
	//int n = abs(delimiters);

	for(k=0; k<=str_len ; k++)
		delimiter[k] = -1;

	if (str == NULL || substr == NULL) return -1;

	/* substr has to be smaller than str */
	if (substr_len > str_len) return -1;

	/* look through str for substr, stopping at end of string or when the length
 * of substr exceeds the remaining number of characters to be searched */ 
	while (str[++i] != '\0' && (str_len - i + 1) > substr_len) 
	{
		for (str_index = 0; str_index < substr_len; ++str_index)
		{
			/* definitely not at location i */
			if (str[i + str_index] != substr[str_index])
				break;
			/* if last letter matches, then we know the whole thing matched */
			else if (str_index == substr_len - 1)
			{
				if(delimiters >= 1)
				{
					i += substr_len -1;
					delimiter[++ind_delim] = i;
					//printf("delimiter[%d] = %d\n", ind_delim, delimiter[ind_delim]);
				}
				else if(delimiters == 0)
					return i;
				else if(delimiters == -1)
					total++;
			}
		}
	}

	if(delimiters == 0)
		return -1;						/* substr not present in str */
	else if(delimiters == -1)
		return total;					/* the total numbers of substr */
	else if(delimiters < ind_delim)
		matchpos = delimiter[delimiters];
	else
		matchpos = delimiter[ind_delim];

	return matchpos;
}

/* ======================(function header)========================
Function Name: int strcutail (char *str, const char *n, int pos)
Description: To remove the sub-string which is starting at 
 n-th delimiter(or include it) to the end of input string.
Arguments: char *, const char *
Return: Returns the string which was cut the tailed sub-string off.
written by Jackie Xie
Date : 2011/07/15
================================================================*/
char *strcutail (char *str, const char *n, int pos)
{
	int i, _newStrLen = matchStrPosAt(n, str, abs(pos));
	char* _new;
	
	if(_newStrLen >= 0){
		if (pos >= 0)
			++_newStrLen;			
		if ((_new = (char *)malloc(_newStrLen)) == NULL)
			return "NULL";

		(_new)[_newStrLen] = '\0';		

		/* copy sub-string from the head of the string to the specified delimiter */
		for (i = 0; i < _newStrLen; ++i)
			(_new)[i] = str[i];

		strcpy(str, _new);
		free (_new);
	}
	return str;
}

/* ======================(function header)========================
Function Name: int strmhead (char *str, const char *n, int pos)
Description: To cut the front of sub-string which is starting at the
 matched delimiter and ending of the input string.
Arguments: char *, const char *
Return: The string which was cut the front of input string till the 
 specified delimiter.
written by Jackie Xie
Date : 2011/08/12
================================================================*/
char *strmhead (char *str, const char *n, int pos)
{
	int i, _matchedStrLen = matchStrPosAt(n, str, abs(pos));
	int str_len = strlen(str);
	int _newStrLen = 0;
	
	char* _new;
	
	if(_matchedStrLen >= 0){
		if (pos >= 0)
			_matchedStrLen -= strlen(n);
			
		_newStrLen = str_len - _matchedStrLen;

		if ((_new = (char *)malloc(_newStrLen)) == NULL)
			return "NULL";

		(_new)[_newStrLen+1] = '\0';		

		/* copy sub-string from specified delimiter */
		for (i = 0; i < _newStrLen; ++i)
			(_new)[i] = str[_matchedStrLen +1 + i];
		strcpy(str, _new);
		free (_new);
	}
	
	return str;
}

bool isLeapYear (int year)
{
	if(((year % 4==0) && (year%100 != 0)) || (year % 400 == 0))
	   return true;
	else
		return false;	
}

/*
 * Convert a date to days since 1970.
 * written by jackiexie
 * Date : 2012/02/08
 */
int date2jds(char* datetime)
{
	time_t when;
	struct tm	tm;
	char	*end;

	memset(&tm, 0, sizeof(tm));
	end = strptime(datetime, "%Y-%m-%d", &tm);
	if (end == NULL || *end) {
		fprintf(stderr, "could not parse: %s\n", datetime);
		return 0;
	}

	when = mktime(&tm) / 86400;
	//printf("%u\n", (unsigned) (when));
	return when;
}

/*
 * Convert days since 1970 to a date.
 * written by jackiexie
 * Date : 2012/02/08
 */
int jds2date(int days, char* datetime)
{
	time_t when;
	struct tm	*whentm;
	char	res[64];

	when = days * 24 * 60 * 60;
	if ((whentm = localtime(&when)) == NULL) {
		fprintf(stderr, "localtime: %s\n", strerror(errno));
		return -1;
	}

	strftime(res, sizeof(res) - 1, "%Y-%m-%d", whentm);
	res[sizeof(res) - 1] = '\0';
	//printf("%s\n", res);
	sprintf(datetime, "%s", res);

	return 0;
}

/*
 * Convert [J]<days> to M<month>,<week of month>,<week day> format.
 * written by jackiexie
 * Date : 2012/02/08
 */
int jds2mds(int days, char* dst)
{
	time_t when;
	struct tm	*whentm;
	char	month[4], DayOfMonth[3], weekday[3];
	int WeekOfMonth;

	when = days * 24 * 60 * 60;
	if ((whentm = localtime(&when)) == NULL) {
		fprintf(stderr, "localtime: %s\n", strerror(errno));
		return -1;
	}

	strftime(month, sizeof(month) - 1, "M%m", whentm);
	month[sizeof(month) - 1] = '\0';

	strftime(DayOfMonth, sizeof(DayOfMonth) - 1, "%d", whentm);
	DayOfMonth[sizeof(DayOfMonth) - 1] = '\0';
	/* To find current 'week of month'(by 'day of month'(DayOfMonth) */
	WeekOfMonth = ceil(atof(DayOfMonth) / 7);

	strftime(weekday, sizeof(weekday) - 1, "%w", whentm);
	weekday[sizeof(weekday) - 1] = '\0';

	//printf("%s.%d.%s\n", month, WeekOfMonth, weekday);
	sprintf(dst, "%s.%d.%s", month, WeekOfMonth, weekday);

	return 0;
}

/*
 * Convert days to a date format.
 * written by jackiexie
 * Date : 2012/02/08
 */
int days2date(int Days, char* dst)
{
	time_t baseTime;
	struct tm* pLocalTime=NULL;
	char dt[20];
	int jdays = 0;

	baseTime = time(NULL);
	pLocalTime = localtime(&baseTime);
	pLocalTime->tm_year += 1900;

	sprintf(dt, "%d-1-1", pLocalTime->tm_year);
	jdays = Days + date2jds(dt);
	jdays = (isLeapYear(pLocalTime->tm_year))? jdays+1:jdays;
	jds2date(jdays, dst);
	//return jds2mds(jdays, dst);
	return jdays;
}

/*
 * Convert date to a days format.
 * written by jackiexie
 * Date : 2012/02/08
 */
 int date2days(char* date)
 {
	time_t when;
	struct tm	tm;
	char	*end, dt[20], *year, *month, *day;
	int days = 0, day_of_month = 0;

	year = strdup(date);
	month = strdup(date);
	day  = strdup(date);
	strcutail(year, "-", -1);
	GetStrBetweenStr(month, "-", "-");
	strmhead(day, "-", -2);
	day_of_month = atoi(day);
	sprintf(dt, "%s-1-1", year);
	days = date2jds(dt);
	memset(&tm, 0, sizeof(tm));
	end = strptime(date, "%Y-%m-%d", &tm);
	if (end == NULL || *end || (!strcmp(month, "2") && 
		((day_of_month >= 29 && !isLeapYear(atoi(year))) || 
			(day_of_month > 29 && isLeapYear(atoi(year)))))) {
		fprintf(stderr, "could not parse: %s\n", date);
		return -1;
	}

	when = mktime(&tm) / 86400 - days + 1;
	if(isLeapYear(atoi(year))) --when;
	//printf("date2days = %u\n", (unsigned) (when));
	free(year);

	return when;
 }

int main(int argc, char *argv[])
{
	char help_msg[1024] = "Usage: dtconfig [-d yyyy-mm-dd] [-j <days of this year>] [-m <[J]<days of this year>] [-h]\n\n";
	char *date, dst[64], *tmp;
	int c, days;

	strcat(help_msg, "dtconfig command summary\n");
	strcat(help_msg, "\tdtconfig is a function to convert date format.\n");
	strcat(help_msg, "\t-d：To convert date to days.\n");
	strcat(help_msg, "\t-j：To convert days to date.\n");
	strcat(help_msg, "\t\t leap year : 0 ~ 365 \n");
	strcat(help_msg, "\t\t otherwise : 1 ~ 365 \n");
	strcat(help_msg, "\t-m：To convert 'Jn' to 'Mm.w.d' format. \n");
	strcat(help_msg, "\t\t where 'Jn' is specifies the Julian day, with n between 1 and 365. February 29 is never counted, even in leap years. \n");
	strcat(help_msg, "\t\t where 'n' is the days of this year which means the Julian day, with n between 0 and 365. February 29 is counted in leap years. \n");
	strcat(help_msg, "\t-h：To show this help message.\n");

	if(argc <= 1 || ((isgraph(*argv[1]) || ispunct(*argv[1])) && *argv[1]!='-'))
		fprintf(stderr, "%s", help_msg);

	while ((c = getopt(argc, argv, "D:d:J:j:M:m:h0:?0:0:-")) != -1){
		switch (c) {
			case 'D':
			case 'd':
				date = optarg;
				days = date2days(date);
				printf("%d\n", days);
				break;
			case 'J':
			case 'j':
				days = atoi(optarg);
				date = strdup("yyyy-mm-dd");
				days2date(days, date);
				printf("%s\n", date);
				free(date);
				break;
			case 'M':
			case 'm':
				tmp = strdup(optarg);
				if(strstr(tmp, "J")){
					days = atoi(strmhead(tmp, "J", -1));
					if(days != 59){
						days = days2date(days, dst);
						jds2mds(days, dst);
					}
					else
						printf("Invalid !!!\n");
				}
				else{
					days = atoi(optarg);
					/* step 1 : to find the date by days */
					days = days2date(days, dst);
					/* step 2 : to find the result by Julian day & date */
					jds2mds(days, dst);
				}
				printf("%s\n", dst);
				free(tmp);
				break;
			case 'h':
			case '?':
			default:
				fprintf(stderr, "%s", help_msg);
				exit(0);
				break;
		}
	}

	return 0;
}