时间和字符串格式的相互转换

visual studio 2022测试通过

1 timeformat.h

#pragma once
#ifndef TIME_FORMAT_H
#define TIME_FORMAT_H
#include
<ctype.h>
#include
<string>
#include
<time.h>
#include <string>
#include <time.h>
#include <sstream>
using namespace std;
//source:https ://blog.csdn.net/wisage/article/details/6269997
//https://www.jianshu.com/p/da8fee6702c9
/*
* We do not implement alternate representations. However, we always
* check whether a given modifier is allowed for a certain conversion.
*/
#define
ALT_E
0x01
#define
ALT_O
0x02
//#define LEGAL_ALT(x)
{ if (alt_format & ~(x)) return (0); }
#define
LEGAL_ALT(x)
{ ; }
#define
TM_YEAR_BASE
(1900)
static
int conv_num(const char**, int*, int, int);
static
int strncasecmp(char* s1, char* s2, size_t n);
static
const char* day[7] = {
"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday",
"Friday", "Saturday"
};
static
const char* abday[7] = {
"Sun","Mon","Tue","Wed","Thu","Fri","Sat"
};
static
const char* mon[12] = {
"January", "February", "March", "April", "May", "June", "July",
"August", "September", "October", "November", "December"
};
static
const char* abmon[12] = {
"Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
};
static
const char* am_pm[2] = {
"AM", "PM"
};
char* strptime(const char* buf, const char* fmt, struct tm* tm);
static
int conv_num(const char** buf, int* dest, int llim, int ulim);
int
strncasecmp(char* s1, char* s2, size_t n);
time_t str2date(const string& dateStr, const char& dateDiv = '-');
time_t str2time(const string& dateStr, const char& dateDiv = '-', const char& timeDiv = ':');
time_t str2time(const string& dateStr, const string& format);
time_t mkgmtime(tm* pTm);
std::string ShowHM(const time_t& t, const char& timeDiv = ':');
std::string ShowHMS(const time_t& t, const char& timeDiv = ':');
std::string ShowYMD(const time_t& t, const char& dateDiv = '-');
std::string ShowDateTime(const time_t& t, const char& dateDiv = '-', const char& timeDiv = ':');
std::string ShowDateTime(const tm& t, const char& dateDiv = '-', const char& timeDiv = ':');
std::string ShowDateTime(const time_t* t, const string& format);
std::string ShowDateTime(const tm* t, const string& format);
#endif // !TIME_FORMAT_H

2 timeformat.cpp

#include "timeformat.h"
char*
strptime(const char* buf, const char* fmt, struct tm* tm)
{
char c;
const char* bp;
size_t len = 0;
int alt_format, i, split_year = 0;
bp = buf;
while ((c = *fmt) != '') {
/* Clear `alternate' modifier prior to new conversion. */
alt_format = 0;
/* Eat up white-space. */
if (isspace(c)) {
while (isspace(*bp))
bp++;
fmt++;
continue;
}
if ((c = *fmt++) != '%')
goto literal;
again:
switch (c = *fmt++) {
case '%': /* "%%" is converted to "%". */
literal :
if (c != *bp++)
return (0);
break;
/*
* "Alternative" modifiers. Just set the appropriate flag
* and start over again.
*/
case 'E': /* "%E?" alternative conversion modifier. */
LEGAL_ALT(0);
alt_format |= ALT_E;
goto again;
case 'O': /* "%O?" alternative conversion modifier. */
LEGAL_ALT(0);
alt_format |= ALT_O;
goto again;
/*
* "Complex" conversion rules, implemented through recursion.
*/
case 'c': /* Date and time, using the locale's format. */
LEGAL_ALT(ALT_E);
if (!(bp = strptime(bp, "%x %X", tm)))
return (0);
break;
case 'D': /* The date as "%m/%d/%y". */
LEGAL_ALT(0);
if (!(bp = strptime(bp, "%m/%d/%y", tm)))
return (0);
break;
case 'R': /* The time as "%H:%M". */
LEGAL_ALT(0);
if (!(bp = strptime(bp, "%H:%M", tm)))
return (0);
break;
case 'r': /* The time in 12-hour clock representation. */
LEGAL_ALT(0);
if (!(bp = strptime(bp, "%I:%M:%S %p", tm)))
return (0);
break;
case 'T': /* The time as "%H:%M:%S". */
LEGAL_ALT(0);
if (!(bp = strptime(bp, "%H:%M:%S", tm)))
return (0);
break;
case 'X': /* The time, using the locale's format. */
LEGAL_ALT(ALT_E);
if (!(bp = strptime(bp, "%H:%M:%S", tm)))
return (0);
break;
case 'x': /* The date, using the locale's format. */
LEGAL_ALT(ALT_E);
if (!(bp = strptime(bp, "%m/%d/%y", tm)))
return (0);
break;
/*
* "Elementary" conversion rules.
*/
case 'A': /* The day of week, using the locale's form. */
case 'a':
LEGAL_ALT(0);
for (i = 0; i < 7; i++) {
/* Full name. */
len = strlen(day[i]);
if (strncasecmp((char*)(day[i]), (char*)bp, len) == 0)
break;
/* Abbreviated name. */
len = strlen(abday[i]);
if (strncasecmp((char*)(abday[i]), (char*)bp, len) == 0)
break;
}
/* Nothing matched. */
if (i == 7)
return (0);
tm->tm_wday = i;
bp += len;
break;
case 'B': /* The month, using the locale's form. */
case 'b':
case 'h':
LEGAL_ALT(0);
for (i = 0; i < 12; i++) {
/* Full name. */
len = strlen(mon[i]);
if (strncasecmp((char*)(mon[i]), (char*)bp, len) == 0)
break;
/* Abbreviated name. */
len = strlen(abmon[i]);
if (strncasecmp((char*)(abmon[i]), (char*)bp, len) == 0)
break;
}
/* Nothing matched. */
if (i == 12)
return (0);
tm->tm_mon = i;
bp += len;
break;
case 'C': /* The century number. */
LEGAL_ALT(ALT_E);
if (!(conv_num(&bp, &i, 0, 99)))
return (0);
if (split_year) {
tm->tm_year = (tm->tm_year % 100) + (i * 100);
}
else {
tm->tm_year = i * 100;
split_year = 1;
}
break;
case 'd': /* The day of month. */
case 'e':
LEGAL_ALT(ALT_O);
if (!(conv_num(&bp, &tm->tm_mday, 1, 31)))
return (0);
break;
case 'k': /* The hour (24-hour clock representation). */
LEGAL_ALT(0);
/* FALLTHROUGH */
case 'H':
LEGAL_ALT(ALT_O);
if (!(conv_num(&bp, &tm->tm_hour, 0, 23)))
return (0);
break;
case 'l': /* The hour (12-hour clock representation). */
LEGAL_ALT(0);
/* FALLTHROUGH */
case 'I':
LEGAL_ALT(ALT_O);
if (!(conv_num(&bp, &tm->tm_hour, 1, 12)))
return (0);
if (tm->tm_hour == 12)
tm->tm_hour = 0;
break;
case 'j': /* The day of year. */
LEGAL_ALT(0);
if (!(conv_num(&bp, &i, 1, 366)))
return (0);
tm->tm_yday = i - 1;
break;
case 'M': /* The minute. */
LEGAL_ALT(ALT_O);
if (!(conv_num(&bp, &tm->tm_min, 0, 59)))
return (0);
break;
case 'm': /* The month. */
LEGAL_ALT(ALT_O);
if (!(conv_num(&bp, &i, 1, 12)))
return (0);
tm->tm_mon = i - 1;
break;
case 'p': /* The locale's equivalent of AM/PM. */
LEGAL_ALT(0);
/* AM? */
if (_stricmp(am_pm[0], bp) == 0) {
if (tm->tm_hour > 11)
return (0);
bp += strlen(am_pm[0]);
break;
}
/* PM? */
else if (_stricmp(am_pm[1], bp) == 0) {
if (tm->tm_hour > 11)
return (0);
tm->tm_hour += 12;
bp += strlen(am_pm[1]);
break;
}
/* Nothing matched. */
return (0);
case 'S': /* The seconds. */
LEGAL_ALT(ALT_O);
if (!(conv_num(&bp, &tm->tm_sec, 0, 61)))
return (0);
break;
case 'U': /* The week of year, beginning on sunday. */
case 'W': /* The week of year, beginning on monday. */
LEGAL_ALT(ALT_O);
/*
* XXX This is bogus, as we can not assume any valid
* information present in the tm structure at this
* point to calculate a real value, so just check the
* range for now.
*/
if (!(conv_num(&bp, &i, 0, 53)))
return (0);
break;
case 'w': /* The day of week, beginning on sunday. */
LEGAL_ALT(ALT_O);
if (!(conv_num(&bp, &tm->tm_wday, 0, 6)))
return (0);
break;
case 'Y': /* The year. */
LEGAL_ALT(ALT_E);
if (!(conv_num(&bp, &i, 0, 9999)))
return (0);
tm->tm_year = i - TM_YEAR_BASE;
break;
case 'y': /* The year within 100 years of the epoch. */
LEGAL_ALT(ALT_E | ALT_O);
if (!(conv_num(&bp, &i, 0, 99)))
return (0);
if (split_year) {
tm->tm_year = ((tm->tm_year / 100) * 100) + i;
break;
}
split_year = 1;
if (i <= 68)
tm->tm_year = i + 2000 - TM_YEAR_BASE;
else
tm->tm_year = i + 1900 - TM_YEAR_BASE;
break;
/*
* Miscellaneous conversions.
*/
case 'n': /* Any kind of white-space. */
case 't':
LEGAL_ALT(0);
while (isspace(*bp))
bp++;
break;
default: /* Unknown/unsupported conversion. */
return (0);
}
}
/* LINTED functional specification */
return ((char*)bp);
}
static
int
conv_num(const char** buf, int* dest, int llim, int ulim)
{
int result = 0;
/* The limit also determines the number of valid digits. */
int rulim = ulim;
if (**buf < '0' || **buf > '9')
return (0);
do {
result *= 10;
result += *(*buf)++ - '0';
rulim /= 10;
} while ((result * 10 <= ulim) && rulim && **buf >= '0' && **buf <= '9');
if (result < llim || result > ulim)
return (0);
*dest = result;
return (1);
}
int
strncasecmp(char* s1, char* s2, size_t n)
{
if (n == 0)
return 0;
while (n-- != 0 && tolower(*s1) == tolower(*s2))
{
if (n == 0 || *s1 == '/0' || *s2 == '/0')
break;
s1++;
s2++;
}
return tolower(*(unsigned char*)s1) - tolower(*(unsigned char*)s2);
}
// time转格式化字符串=====================================
std::string ShowDateTime(const tm* t, const string& format)
{
char s[100];
strftime(s, sizeof(s), format.c_str(), t);
return string(s);
}
std::string ShowDateTime(const time_t* t, const string& format)
{
tm _tm;
gmtime_s(&_tm, t);
return ShowDateTime(&_tm, format);
}
std::string ShowDateTime(const tm& t, const char& dateDiv, const char& timeDiv)
{
ostringstream format;
format << "%Y" << dateDiv << "%m" << dateDiv << "%d" << ' ';
format << "%H" << timeDiv << "%M" << timeDiv << "%S";
return ShowDateTime(&t, format.str());
}
std::string ShowDateTime(const time_t& t, const char& dateDiv, const char& timeDiv)
{
ostringstream format;
format << "%Y" << dateDiv << "%m" << dateDiv << "%d" << ' ';
format << "%H" << timeDiv << "%M" << timeDiv << "%S";
return ShowDateTime(&t, format.str());
}
std::string ShowYMD(const time_t& t, const char& dateDiv)
{
ostringstream format;
format << "%Y" << dateDiv << "%m" << dateDiv << "%d";
return ShowDateTime(&t, format.str());
}
std::string ShowHMS(const time_t& t, const char& timeDiv)
{
ostringstream format;
format << "%H" << timeDiv << "%M" << timeDiv << "%S";
return ShowDateTime(&t, format.str());
}
std::string ShowHM(const time_t& t, const char& timeDiv)
{
ostringstream format;
format << "%H" << timeDiv << "%M";
return ShowDateTime(&t, format.str());
}
// 格式化字符串转time=====================================
time_t mkgmtime(tm* pTm)
{
unsigned int year = pTm->tm_year + 1900;
unsigned int mon = pTm->tm_mon + 1;
unsigned int day = pTm->tm_mday;
unsigned int hour = pTm->tm_hour;
unsigned int min = pTm->tm_min;
unsigned int sec = pTm->tm_sec;
if (0 >= (int)(mon -= 2)) {
/* 1..12 -> 11,12,1..10 */
mon += 12;
/* Puts Feb last since it has leap day */
year -= 1;
}
return (((
(unsigned long)(year / 4 - year / 100 + year / 400 + 367 * mon / 12 + day) +
year * 365 - 719499
) * 24 + hour /* now have hours */
) * 60 + min /* now have minutes */
) * 60 + sec; /* finally seconds */
}
time_t str2time(const string& dateStr, const string& format)
{
tm t;
memset(&t, 0, sizeof(tm));
strptime(dateStr.c_str(), format.c_str(), &t);// windows下用不了
return mkgmtime(&t);
}
time_t str2time(const string& dateStr, const char& dateDiv, const char& timeDiv)
{
string format = "%Y-%m-%d %H:%M:%S";
if (dateDiv != '-')
{
format[2] = format[5] = dateDiv;
}
if (timeDiv != ':')
{
format[11] = format[14] = timeDiv;
}
return str2time(dateStr.c_str(), format);
}
time_t str2date(const string& dateStr, const char& dateDiv)
{
string format = "%Y-%m-%d";
if (dateDiv != '-')
{
format[2] = format[5] = dateDiv;
}
return str2time(dateStr.c_str(), format);
}

3 测试程序

#include "timeformat.h"
#include <iostream>
using namespace std;
int main()
{
// 测试
struct tm* newtime;
newtime = new tm();
//if use this, include conio.h
//memset(&newtime, 0x00, sizeof(struct tm));
strptime("Tue, 27 Nov 2007 05:35:53", "%a, %d %b %Y %H:%M:%S", newtime);
//strptime("03/10/2004 15:54:19","%d/%m/%Y %H:%M:%S",&newtime);
time_t now = time(0);
cout << ShowYMD(now) << endl;
cout << str2date(ShowYMD(now)) << endl;
system("pause");// 暂停以显示终端窗口
return 0;
}

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