/*
 vi:ts=8:sw=8:noet
 * Copyright (c) 2006 Luke Dunstan <infidel@users.sourceforge.net>
 * Partly based on code by David Kashtan, Validus Medical Systems
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

/*
 * This file provides various functions that are available on desktop Windows
 * but not on Windows CE
 */

#ifdef _MSC_VER
/* Level 4 warnings caused by windows.h */
#pragma warning(disable : 4214) // nonstandard extension used : bit field types other than int
#pragma warning(disable : 4115) // named type definition in parentheses
#pragma warning(disable : 4201) // nonstandard extension used : nameless struct/union
#pragma warning(disable : 4514) // unreferenced inline function has been removed
#pragma warning(disable : 4244) // conversion from 'int ' to 'unsigned short ', possible loss of data
#pragma warning(disable : 4100) // unreferenced formal parameter
#endif

#include <windows.h>
#include <stdlib.h>

#include "compat_wince.h"


static WCHAR *to_wide_string(LPCSTR pStr)
{
	int nwide;
	WCHAR *buf;

	if(pStr == NULL)
		return NULL;
	nwide = MultiByteToWideChar(CP_ACP, 0, pStr, -1, NULL, 0);
	if(nwide == 0)
		return NULL;
	buf = malloc(nwide * sizeof(WCHAR));
	if(buf == NULL) {
		SetLastError(ERROR_NOT_ENOUGH_MEMORY);
		return NULL;
	}
	if(MultiByteToWideChar(CP_ACP, 0, pStr, -1, buf, nwide) == 0) {
		free(buf);
		return NULL;
	}
	return buf;
}

FILE *fdopen(int handle, const char *mode)
{
	WCHAR *wmode = to_wide_string(mode);
	FILE *result;

	if(wmode != NULL)
		result = _wfdopen((void *)handle, wmode);
	else
		result = NULL;
	free(wmode);
	return result;
}

/*
 *	Time conversion constants
 */
#define FT_EPOCH (116444736000000000i64)
#define	FT_TICKS (10000000i64)

 /*
 *	Convert a FILETIME to a time_t
 */
static time_t convert_FILETIME_to_time_t(FILETIME *File_Time)
{
	__int64 Temp;

	/*
	 *	Convert the FILETIME structure to 100nSecs since 1601 (as a 64-bit value)
	 */
	Temp = (((__int64)File_Time->dwHighDateTime) << 32) + (__int64)File_Time->dwLowDateTime;
	/*
	 *	Convert to seconds from 1970
	 */
	return((time_t)((Temp - FT_EPOCH) / FT_TICKS));
}

/*
 *	Convert a FILETIME to a tm structure
 */
static struct tm *Convert_FILETIME_To_tm(FILETIME *File_Time)
{
	SYSTEMTIME System_Time;
	static struct tm tm = {0};
	static const short Day_Of_Year_By_Month[12] = {(short)(0),
						       (short)(31),
						       (short)(31 + 28),
						       (short)(31 + 28 + 31),
						       (short)(31 + 28 + 31 + 30),
						       (short)(31 + 28 + 31 + 30 + 31),
						       (short)(31 + 28 + 31 + 30 + 31 + 30),
						       (short)(31 + 28 + 31 + 30 + 31 + 30 + 31),
						       (short)(31 + 28 + 31 + 30 + 31 + 30 + 31 + 31),
						       (short)(31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30),
						       (short)(31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31),
						       (short)(31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30)};


	/*
	 *	Turn the FILETIME into a SYSTEMTIME
	 */
	FileTimeToSystemTime(File_Time, &System_Time);
	/*
	 *	Use SYSTEMTIME to fill in the tm structure
	 */
	tm.tm_sec = System_Time.wSecond;
	tm.tm_min = System_Time.wMinute;
	tm.tm_hour = System_Time.wHour;
	tm.tm_mday = System_Time.wDay;
	tm.tm_mon = System_Time.wMonth - 1;
	tm.tm_year = System_Time.wYear - 1900;
	tm.tm_wday = System_Time.wDayOfWeek;
	tm.tm_yday = Day_Of_Year_By_Month[tm.tm_mon] + tm.tm_mday - 1;
	if (tm.tm_mon >= 2) {
		/*
		 *	Check for leap year (every 4 years but not every 100 years but every 400 years)
		 */
		if ((System_Time.wYear % 4) == 0) {
			/*
			 *	It Is a 4th year
			 */
			if ((System_Time.wYear % 100) == 0) {
				/*
				 *	It is a 100th year
				 */
				if ((System_Time.wYear % 400) == 0) {
					/*
					 *	It is a 400th year: It is a leap year
					 */
					tm.tm_yday++;
				}
			} else {
				/*
				 *	It is not a 100th year: It is a leap year
				 */
				tm.tm_yday++;
			}
		}
	}
	return(&tm);
}

/*
 *	Convert a time_t to a FILETIME
 */
static void Convert_time_t_To_FILETIME(time_t Time, FILETIME *File_Time)
{
	__int64 Temp;

	/*
	 *	Use 64-bit calculation to convert seconds since 1970 to
	 *	100nSecs since 1601
	 */
	Temp = ((__int64)Time * FT_TICKS) + FT_EPOCH;
	/*
	 *	Put it into the FILETIME structure
	 */
	File_Time->dwLowDateTime = (DWORD)Temp;
	File_Time->dwHighDateTime = (DWORD)(Temp >> 32);
}

/*
 *	Convert a tm structure to a FILETIME
 */
static FILETIME *Convert_tm_To_FILETIME(struct tm *tm)
{
	SYSTEMTIME System_Time;
	static FILETIME File_Time = {0};

	/*
	 *	Use the tm structure to fill in a SYSTEM
	 */
	System_Time.wYear = tm->tm_year + 1900;
	System_Time.wMonth = tm->tm_mon + 1;
	System_Time.wDayOfWeek = tm->tm_wday;
	System_Time.wDay = tm->tm_mday;
	System_Time.wHour = tm->tm_hour;
	System_Time.wMinute = tm->tm_min;
	System_Time.wSecond = tm->tm_sec;
	System_Time.wMilliseconds = 0;
	/*
	 *	Convert it to a FILETIME and return it
	 */
	SystemTimeToFileTime(&System_Time, &File_Time);
	return(&File_Time);
}


/************************************************************************/
/*									*/
/*	Errno emulation:  There is no errno on Windows/CE and we need	*/
/*			  to make it per-thread.  So we have a function	*/
/*			  that returns a pointer to the errno for the	*/
/*			  current thread.				*/
/*									*/
/*			  If there is ONLY the main thread then we can	*/
/* 			  quickly return some static storage.		*/
/*									*/
/*			  If we have multiple threads running, we use	*/
/*			  Thread-Local Storage to hold the pointer	*/
/*									*/
/************************************************************************/

/*
 *	Function pointer for returning errno pointer
 */
static int *Initialize_Errno(void);
int *(*__WinCE_Errno_Pointer_Function)(void) = Initialize_Errno;

/*
 *	Static errno storage for the main thread
 */
static int Errno_Storage = 0;

/*
 *	Thread-Local storage slot for errno
 */
static int TLS_Errno_Slot = 0xffffffff;

/*
 *	Number of threads we have running and critical section protection
 *	for manipulating it
 */
static int Number_Of_Threads = 0;
static CRITICAL_SECTION Number_Of_Threads_Critical_Section;

/*
 *	For the main thread only -- return the errno pointer
 */
static int *Get_Main_Thread_Errno(void)
{
	return &Errno_Storage;
}

/*
 *	When there is more than one thread -- return the errno pointer
 */
static int *Get_Thread_Errno(void)
{
	return (int *)TlsGetValue(TLS_Errno_Slot);
}

/*
 *	Initialize a thread's errno
 */
static void Initialize_Thread_Errno(int *Errno_Pointer)
{
	/*
	 *	Make sure we have a slot
	 */
	if (TLS_Errno_Slot == 0xffffffff) {
		/*
		 *	No: Get one
		 */
		TLS_Errno_Slot = (int)TlsAlloc();
		if (TLS_Errno_Slot == 0xffffffff) ExitProcess(3);
	}
	/*
	 *	We can safely check for 0 threads, because
	 *	only the main thread will be initializing
	 *	at this point.  Make sure the critical
	 *	section that protects the number of threads
	 *	is initialized
	 */
	if (Number_Of_Threads == 0)
		InitializeCriticalSection(&Number_Of_Threads_Critical_Section);
	/*
	 *	Store the errno pointer
	 */
	if (TlsSetValue(TLS_Errno_Slot, (LPVOID)Errno_Pointer) == 0) ExitProcess(3);
	/*
	 *	Bump the number of threads
	 */
	EnterCriticalSection(&Number_Of_Threads_Critical_Section);
	Number_Of_Threads++;
	if (Number_Of_Threads > 1) {
		/*
		 *	We have threads other than the main thread:
		 *	  Use thread-local storage
		 */
		__WinCE_Errno_Pointer_Function = Get_Thread_Errno;
	}
	LeaveCriticalSection(&Number_Of_Threads_Critical_Section);
}

/*
 *	Initialize errno emulation on Windows/CE (Main thread)
 */
static int *Initialize_Errno(void)
{
	/*
	 *	Initialize the main thread's errno in thread-local storage
	 */
	Initialize_Thread_Errno(&Errno_Storage);
	/*
	 *	Set the errno function to be the one that returns the
	 *	main thread's errno
	 */
	__WinCE_Errno_Pointer_Function = Get_Main_Thread_Errno;
	/*
	 *	Return the main thread's errno
	 */
	return &Errno_Storage;
}

/*
 *	Initialize errno emulation on Windows/CE (New thread)
 */
void __WinCE_Errno_New_Thread(int *Errno_Pointer)
{
	Initialize_Thread_Errno(Errno_Pointer);
}

/*
 *	Note that a thread has exited
 */
void __WinCE_Errno_Thread_Exit(void)
{
	/*
	 *	Decrease the number of threads
	 */
	EnterCriticalSection(&Number_Of_Threads_Critical_Section);
	Number_Of_Threads--;
	if (Number_Of_Threads <= 1) {
		/*
		 *	We only have the main thread
		 */
		__WinCE_Errno_Pointer_Function = Get_Main_Thread_Errno;
	}
	LeaveCriticalSection(&Number_Of_Threads_Critical_Section);
}


char *
strerror(int errnum)
{
	return "(strerror not implemented)";
}

#define FT_EPOCH (116444736000000000i64)
#define	FT_TICKS (10000000i64)

int
_wstat(const WCHAR *path, struct _stat *buffer)
{
	WIN32_FIND_DATA data;
	HANDLE handle;
	WCHAR *p;

	/* Fail if wildcard characters are specified */
	if (wcscspn(path, L"?*") != wcslen(path))
		return -1;

	handle = FindFirstFile(path, &data);
	if (handle == INVALID_HANDLE_VALUE) {
		errno = GetLastError();
		return -1;
	}
	FindClose(handle);

	/* Found: Convert the file times */
	buffer->st_mtime = convert_FILETIME_to_time_t(&data.ftLastWriteTime);
	if (data.ftLastAccessTime.dwLowDateTime || data.ftLastAccessTime.dwHighDateTime)
		buffer->st_atime = convert_FILETIME_to_time_t(&data.ftLastAccessTime);
	else
		buffer->st_atime = buffer->st_mtime;
	if (data.ftCreationTime.dwLowDateTime || data.ftCreationTime.dwHighDateTime)
		buffer->st_ctime = convert_FILETIME_to_time_t(&data.ftCreationTime);
	else
		buffer->st_ctime = buffer->st_mtime;

	/* Convert the file modes */
	buffer->st_mode = (unsigned short)((data.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) ? (S_IFDIR | S_IEXEC) : S_IFREG);
	buffer->st_mode |= (data.dwFileAttributes & FILE_ATTRIBUTE_READONLY) ? S_IREAD : (S_IREAD | S_IWRITE);
	if((p = wcsrchr(path, L'.')) != NULL) {
		p++;
		if (_wcsicmp(p, L".exe") == 0)
			buffer->st_mode |= S_IEXEC;
	}
	buffer->st_mode |= (buffer->st_mode & 0700) >> 3;
	buffer->st_mode |= (buffer->st_mode & 0700) >> 6;
	/* Set the other information */
	buffer->st_nlink = 1;
	buffer->st_size = (unsigned long int)data.nFileSizeLow;
	buffer->st_uid = 0;
	buffer->st_gid = 0;
	buffer->st_ino = 0 /*data.dwOID ?*/;
	buffer->st_dev = 0;

	return 0;	/* success */
}

/*
 *	Helper function for cemodule -- do an fstat() operation on a Win32 File Handle
 */
int
_fstat(int handle, struct _stat *st)
{
	BY_HANDLE_FILE_INFORMATION Data;

	/*
	 *	Get the file information
	 */
	if (!GetFileInformationByHandle((HANDLE)handle, &Data)) {
		/*
		 *	Return error
		 */
		errno = GetLastError();
		return(-1);
	}
	/*
	 *	Found: Convert the file times
	 */
	st->st_mtime=(time_t)((*(__int64*)&Data.ftLastWriteTime-FT_EPOCH)/FT_TICKS);
	if(Data.ftLastAccessTime.dwLowDateTime || Data.ftLastAccessTime.dwHighDateTime)
		st->st_atime=(time_t)((*(__int64*)&Data.ftLastAccessTime-FT_EPOCH)/FT_TICKS);
	else
		st->st_atime=st->st_mtime ;
	if(Data.ftCreationTime.dwLowDateTime || Data.ftCreationTime.dwHighDateTime )
		st->st_ctime=(time_t)((*(__int64*)&Data.ftCreationTime-FT_EPOCH)/FT_TICKS);
	else
		st->st_ctime=st->st_mtime ;
	/*
	 *	Convert the file modes
	 */
	st->st_mode = (unsigned short)((Data.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) ? (S_IFDIR | S_IEXEC) : S_IFREG);
	st->st_mode |= (Data.dwFileAttributes & FILE_ATTRIBUTE_READONLY) ? S_IREAD : (S_IREAD | S_IWRITE);
	st->st_mode |= (st->st_mode & 0700) >> 3;
	st->st_mode |= (st->st_mode & 0700) >> 6;
	/*
	 *	Set the other information
	 */
	st->st_nlink=1;
	st->st_size=(unsigned long int)Data.nFileSizeLow;
	st->st_uid=0;
	st->st_gid=0;
	st->st_ino=0;
	st->st_dev=0;
	/*
	 *	Return success
	 */
	return(0);
}

int _wopen(const wchar_t *filename, int oflag, ...)
{
	DWORD Access, ShareMode, CreationDisposition;
	HANDLE Handle;
	static int Modes[4] = {0, (GENERIC_READ | GENERIC_WRITE), GENERIC_READ, GENERIC_WRITE};

	/*
	 *	Calculate the CreateFile arguments
	 */
	Access = Modes[oflag & O_MODE_MASK];
	ShareMode = (oflag & O_EXCL) ? 0 : (FILE_SHARE_READ | FILE_SHARE_WRITE);
	if (oflag & O_TRUNC)
		CreationDisposition = (oflag & O_CREAT) ? CREATE_ALWAYS : TRUNCATE_EXISTING;
	else
		CreationDisposition = (oflag & O_CREAT) ? CREATE_NEW : OPEN_EXISTING;

	Handle = CreateFileW(filename, Access, ShareMode, NULL, CreationDisposition, FILE_ATTRIBUTE_NORMAL, NULL);

	/*
	 *	Deal with errors
	 */
	if (Handle == INVALID_HANDLE_VALUE) {
		errno = GetLastError();
		if ((errno == ERROR_ALREADY_EXISTS) || (errno == ERROR_FILE_EXISTS))
			errno = ERROR_ALREADY_EXISTS;
		return -1;
	}
	/*
	 *	Return the handle
	 */
	return (int)Handle;
}

int
_close(int handle)
{
	if(CloseHandle((HANDLE)handle))
		return 0;
	errno = GetLastError();
	return -1;
}

int
_write(int handle, const void *buffer, unsigned int count)
{
	DWORD numwritten = 0;
	if(!WriteFile((HANDLE)handle, buffer, count, &numwritten, NULL)) {
		errno = GetLastError();
		return -1;
	}
	return numwritten;
}

int
_read(int handle, void *buffer, unsigned int count)
{
	DWORD numread = 0;
	if(!ReadFile((HANDLE)handle, buffer, count, &numread, NULL)) {
		errno = GetLastError();
		return -1;
	}
	return numread;
}

long
_lseek(int handle, long offset, int origin)
{
	DWORD dwMoveMethod;
	DWORD result;

	switch(origin) {
		default:
			errno = EINVAL;
			return -1L;
		case SEEK_SET:
			dwMoveMethod = FILE_BEGIN;
			break;
		case SEEK_CUR:
			dwMoveMethod = FILE_CURRENT;
			break;
		case SEEK_END:
			dwMoveMethod = FILE_END;
			break;
	}
	result = SetFilePointer((HANDLE)handle, offset, NULL, dwMoveMethod);
	if(result == 0xFFFFFFFF) {
		errno = GetLastError();
		return -1;
	}
	return (long)result;
}

int
_wmkdir(const wchar_t *dirname)
{
	if(!CreateDirectoryW(dirname, NULL)) {
		errno = GetLastError();
		return -1;
	}
	return 0;
}

int
_wremove(const wchar_t *filename)
{
	if(!DeleteFileW(filename)) {
		errno = GetLastError();
		return -1;
	}
	return 0;
}

int
_wrename(const wchar_t *oldname, const wchar_t *newname)
{
	if(!MoveFileW(oldname, newname)) {
		errno = GetLastError();
		return -1;
	}
	return 0;
}

wchar_t *
_wgetcwd(wchar_t *buffer, int maxlen)
{
	wchar_t *result;
	WCHAR wszPath[MAX_PATH + 1];
	WCHAR *p;

	if(!GetModuleFileNameW(NULL, wszPath, MAX_PATH + 1)) {
		errno = GetLastError();
		return NULL;
	}
	/* Remove the filename part of the path to leave the directory */
	p = wcsrchr(wszPath, L'\\');
	if(p)
		*p = L'\0';

	if(buffer == NULL)
		result = _wcsdup(wszPath);
	else if(wcslen(wszPath) + 1 > (size_t)maxlen) {
		result = NULL;
		errno = ERROR_INSUFFICIENT_BUFFER;
	} else {
		wcsncpy(buffer, wszPath, maxlen);
		buffer[maxlen - 1] = L'\0';
		result = buffer;
	}
	return result;
}

/*
 *	The missing "C" runtime gmtime() function
 */
struct tm *gmtime(const time_t *TimeP)
{
	FILETIME File_Time;

	/*
	 *	Deal with null time pointer
	 */
	if (!TimeP) return(NULL);
	/*
	 *	time_t -> FILETIME -> tm
	 */
	Convert_time_t_To_FILETIME(*TimeP, &File_Time);
	return(Convert_FILETIME_To_tm(&File_Time));
}

/*
 *	The missing "C" runtime localtime() function
 */
struct tm *localtime(const time_t *TimeP)
{
	FILETIME File_Time, Local_File_Time;

	/*
	 *	Deal with null time pointer
	 */
	if (!TimeP) return(NULL);
	/*
	 *	time_t -> FILETIME -> Local FILETIME -> tm
	 */
	Convert_time_t_To_FILETIME(*TimeP, &File_Time);
	FileTimeToLocalFileTime(&File_Time, &Local_File_Time);
	return(Convert_FILETIME_To_tm(&Local_File_Time));
}

/*
 *	The missing "C" runtime mktime() function
 */
time_t mktime(struct tm *tm)
{
	FILETIME *Local_File_Time;
	FILETIME File_Time;

	/*
	 *	tm -> Local FILETIME -> FILETIME -> time_t
	 */
	Local_File_Time = Convert_tm_To_FILETIME(tm);
	LocalFileTimeToFileTime(Local_File_Time, &File_Time);
	return(convert_FILETIME_to_time_t(&File_Time));
}

/*
 *	Missing "C" runtime time() function
 */
time_t time(time_t *TimeP)
{
	SYSTEMTIME System_Time;
	FILETIME File_Time;
	time_t Result;

	/*
	 *	Get the current system time
	 */
	GetSystemTime(&System_Time);
	/*
	 *	SYSTEMTIME -> FILETIME -> time_t
	 */
	SystemTimeToFileTime(&System_Time, &File_Time);
	Result = convert_FILETIME_to_time_t(&File_Time);
	/*
	 *	Return the time_t
	 */
	if (TimeP) *TimeP = Result;
	return(Result);
}

static char Standard_Name[32] = "GMT";
static char Daylight_Name[32] = "GMT";
char *tzname[2] = {Standard_Name, Daylight_Name};
long timezone = 0;
int daylight = 0;

void tzset(void)
{
	TIME_ZONE_INFORMATION Info;
	int Result;

	/*
	 *	Get our current timezone information
	 */
	Result = GetTimeZoneInformation(&Info);
	switch(Result) {
		/*
		 *	We are on standard time
		 */
		case TIME_ZONE_ID_STANDARD:
			daylight = 0;
			break;
		/*
		 *	We are on daylight savings time
		 */
		case TIME_ZONE_ID_DAYLIGHT:
			daylight = 1;
			break;
		/*
		 *	We don't know the timezone information (leave it GMT)
		 */
		default: return;
	}
	/*
	 *	Extract the timezone information
	 */
	timezone = Info.Bias * 60;
	if (Info.StandardName[0])
		WideCharToMultiByte(CP_ACP, 0, Info.StandardName, -1, Standard_Name, sizeof(Standard_Name) - 1, NULL, NULL);
	if (Info.DaylightName[0])
		WideCharToMultiByte(CP_ACP, 0, Info.DaylightName, -1, Daylight_Name, sizeof(Daylight_Name) - 1, NULL, NULL);
}

/*** strftime() from newlib libc/time/strftime.c ***/

/*
 * Sane snprintf(). Acts like snprintf(), but never return -1 or the
 * value bigger than supplied buffer.
 */
static int
Snprintf(char *buf, size_t buflen, const char *fmt, ...)
{
	va_list		ap;
	int		n;

	if (buflen == 0)
		return (0);

	va_start(ap, fmt);
	n = _vsnprintf(buf, buflen, fmt, ap);
	va_end(ap);

	if (n < 0 || n > (int) buflen - 1) {
		n = buflen - 1;
	}
	buf[n] = '\0';

	return (n);
}

#define snprintf Snprintf

/* from libc/include/_ansi.h */
#define _CONST const
#define	_DEFUN(name, arglist, args)	name(args)
#define	_AND		,
/* from libc/time/local.h */
#define TZ_LOCK
#define TZ_UNLOCK
#define _tzname tzname
#define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0)
#define YEAR_BASE	1900
#define SECSPERMIN	60L
#define MINSPERHOUR	60L
#define HOURSPERDAY	24L
#define SECSPERHOUR	(SECSPERMIN * MINSPERHOUR)

/*
 * strftime.c
 * Original Author:	G. Haley
 * Additions from:	Eric Blake
 *
 * Places characters into the array pointed to by s as controlled by the string
 * pointed to by format. If the total number of resulting characters including
 * the terminating null character is not more than maxsize, returns the number
 * of characters placed into the array pointed to by s (not including the
 * terminating null character); otherwise zero is returned and the contents of
 * the array indeterminate.
 */

/*
FUNCTION
<<strftime>>---flexible calendar time formatter

INDEX
	strftime

ANSI_SYNOPSIS
	#include <time.h>
	size_t strftime(char *<[s]>, size_t <[maxsize]>,
			const char *<[format]>, const struct tm *<[timp]>);

TRAD_SYNOPSIS
	#include <time.h>
	size_t strftime(<[s]>, <[maxsize]>, <[format]>, <[timp]>)
	char *<[s]>;
	size_t <[maxsize]>;
	char *<[format]>;
	struct tm *<[timp]>;

DESCRIPTION
<<strftime>> converts a <<struct tm>> representation of the time (at
<[timp]>) into a null-terminated string, starting at <[s]> and occupying
no more than <[maxsize]> characters.

You control the format of the output using the string at <[format]>.
<<*<[format]>>> can contain two kinds of specifications: text to be
copied literally into the formatted string, and time conversion
specifications.  Time conversion specifications are two- and
three-character sequences beginning with `<<%>>' (use `<<%%>>' to
include a percent sign in the output).  Each defined conversion
specification selects only the specified field(s) of calendar time
data from <<*<[timp]>>>, and converts it to a string in one of the
following ways:

o+
o %a
A three-letter abbreviation for the day of the week. [tm_wday]

o %A
The full name for the day of the week, one of `<<Sunday>>',
`<<Monday>>', `<<Tuesday>>', `<<Wednesday>>', `<<Thursday>>',
`<<Friday>>', or `<<Saturday>>'. [tm_wday]

o %b
A three-letter abbreviation for the month name. [tm_mon]

o %B
The full name of the month, one of `<<January>>', `<<February>>',
`<<March>>', `<<April>>', `<<May>>', `<<June>>', `<<July>>',
`<<August>>', `<<September>>', `<<October>>', `<<November>>',
`<<December>>'. [tm_mon]

o %c
A string representing the complete date and time, in the form
`<<"%a %b %e %H:%M:%S %Y">>' (example "Mon Apr 01 13:13:13
1992"). [tm_sec, tm_min, tm_hour, tm_mday, tm_mon, tm_year, tm_wday]

o %C
The century, that is, the year divided by 100 then truncated.  For
4-digit years, the result is zero-padded and exactly two characters;
but for other years, there may a negative sign or more digits.  In
this way, `<<%C%y>>' is equivalent to `<<%Y>>'. [tm_year]

o %d
The day of the month, formatted with two digits (from `<<01>>' to
`<<31>>'). [tm_mday]

o %D
A string representing the date, in the form `<<"%m/%d/%y">>'.
[tm_mday, tm_mon, tm_year]

o %e
The day of the month, formatted with leading space if single digit
(from `<<1>>' to `<<31>>'). [tm_mday]

o %E<<x>>
In some locales, the E modifier selects alternative representations of
certain modifiers <<x>>.  But in the "C" locale supported by newlib,
it is ignored, and treated as %<<x>>.

o %F
A string representing the ISO 8601:2000 date format, in the form
`<<"%Y-%m-%d">>'. [tm_mday, tm_mon, tm_year]

o %g
The last two digits of the week-based year, see specifier %G (from
`<<00>>' to `<<99>>'). [tm_year, tm_wday, tm_yday]

o %G
The week-based year. In the ISO 8601:2000 calendar, week 1 of the year
includes January 4th, and begin on Mondays. Therefore, if January 1st,
2nd, or 3rd falls on a Sunday, that day and earlier belong to the last
week of the previous year; and if December 29th, 30th, or 31st falls
on Monday, that day and later belong to week 1 of the next year.  For
consistency with %Y, it always has at least four characters.
Example: "%G" for Saturday 2nd January 1999 gives "1998", and for
Tuesday 30th December 1997 gives "1998". [tm_year, tm_wday, tm_yday]

o %h
A three-letter abbreviation for the month name (synonym for
"%b"). [tm_mon]

o %H
The hour (on a 24-hour clock), formatted with two digits (from
`<<00>>' to `<<23>>'). [tm_hour]

o %I
The hour (on a 12-hour clock), formatted with two digits (from
`<<01>>' to `<<12>>'). [tm_hour]

o %j
The count of days in the year, formatted with three digits
(from `<<001>>' to `<<366>>'). [tm_yday]

o %k
The hour (on a 24-hour clock), formatted with leading space if single
digit (from `<<0>>' to `<<23>>'). Non-POSIX extension. [tm_hour]

o %l
The hour (on a 12-hour clock), formatted with leading space if single
digit (from `<<1>>' to `<<12>>'). Non-POSIX extension. [tm_hour]

o %m
The month number, formatted with two digits (from `<<01>>' to `<<12>>').
[tm_mon]

o %M
The minute, formatted with two digits (from `<<00>>' to `<<59>>'). [tm_min]

o %n
A newline character (`<<\n>>').

o %O<<x>>
In some locales, the O modifier selects alternative digit characters
for certain modifiers <<x>>.  But in the "C" locale supported by newlib, it
is ignored, and treated as %<<x>>.

o %p
Either `<<AM>>' or `<<PM>>' as appropriate. [tm_hour]

o %r
The 12-hour time, to the second.  Equivalent to "%I:%M:%S %p". [tm_sec,
tm_min, tm_hour]

o %R
The 24-hour time, to the minute.  Equivalent to "%H:%M". [tm_min, tm_hour]

o %S
The second, formatted with two digits (from `<<00>>' to `<<60>>').  The
value 60 accounts for the occasional leap second. [tm_sec]

o %t
A tab character (`<<\t>>').

o %T
The 24-hour time, to the second.  Equivalent to "%H:%M:%S". [tm_sec,
tm_min, tm_hour]

o %u
The weekday as a number, 1-based from Monday (from `<<1>>' to
`<<7>>'). [tm_wday]

o %U
The week number, where weeks start on Sunday, week 1 contains the first
Sunday in a year, and earlier days are in week 0.  Formatted with two
digits (from `<<00>>' to `<<53>>').  See also <<%W>>. [tm_wday, tm_yday]

o %V
The week number, where weeks start on Monday, week 1 contains January 4th,
and earlier days are in the previous year.  Formatted with two digits
(from `<<01>>' to `<<53>>').  See also <<%G>>. [tm_year, tm_wday, tm_yday]

o %w
The weekday as a number, 0-based from Sunday (from `<<0>>' to `<<6>>').
[tm_wday]

o %W
The week number, where weeks start on Monday, week 1 contains the first
Monday in a year, and earlier days are in week 0.  Formatted with two
digits (from `<<00>>' to `<<53>>'). [tm_wday, tm_yday]

o %x
A string representing the complete date, equivalent to "%m/%d/%y".
[tm_mon, tm_mday, tm_year]

o %X
A string representing the full time of day (hours, minutes, and
seconds), equivalent to "%H:%M:%S". [tm_sec, tm_min, tm_hour]

o %y
The last two digits of the year (from `<<00>>' to `<<99>>'). [tm_year]

o %Y
The full year, equivalent to <<%C%y>>.  It will always have at least four
characters, but may have more.  The year is accurate even when tm_year
added to the offset of 1900 overflows an int. [tm_year]

o %z
The offset from UTC.  The format consists of a sign (negative is west of
Greewich), two characters for hour, then two characters for minutes
(-hhmm or +hhmm).  If tm_isdst is negative, the offset is unknown and no
output is generated; if it is zero, the offset is the standard offset for
the current time zone; and if it is positive, the offset is the daylight
savings offset for the current timezone. The offset is determined from
the TZ environment variable, as if by calling tzset(). [tm_isdst]

o %Z
The time zone name.  If tm_isdst is negative, no output is generated.
Otherwise, the time zone name is based on the TZ environment variable,
as if by calling tzset(). [tm_isdst]

o %%
A single character, `<<%>>'.
o-

RETURNS
When the formatted time takes up no more than <[maxsize]> characters,
the result is the length of the formatted string.  Otherwise, if the
formatting operation was abandoned due to lack of room, the result is
<<0>>, and the string starting at <[s]> corresponds to just those
parts of <<*<[format]>>> that could be completely filled in within the
<[maxsize]> limit.

PORTABILITY
ANSI C requires <<strftime>>, but does not specify the contents of
<<*<[s]>>> when the formatted string would require more than
<[maxsize]> characters.  Unrecognized specifiers and fields of
<<timp>> that are out of range cause undefined results.  Since some
formats expand to 0 bytes, it is wise to set <<*<[s]>>> to a nonzero
value beforehand to distinguish between failure and an empty string.
This implementation does not support <<s>> being NULL, nor overlapping
<<s>> and <<format>>.

<<strftime>> requires no supporting OS subroutines.
*/

static _CONST int dname_len[7] =
{6, 6, 7, 9, 8, 6, 8};

static _CONST char *_CONST dname[7] =
{"Sunday", "Monday", "Tuesday", "Wednesday",
 "Thursday", "Friday", "Saturday"};

static _CONST int mname_len[12] =
{7, 8, 5, 5, 3, 4, 4, 6, 9, 7, 8, 8};

static _CONST char *_CONST mname[12] =
{"January", "February", "March", "April",
 "May", "June", "July", "August", "September", "October", "November",
 "December"};

/* Using the tm_year, tm_wday, and tm_yday components of TIM_P, return
   -1, 0, or 1 as the adjustment to add to the year for the ISO week
   numbering used in "%g%G%V", avoiding overflow.  */
static int
_DEFUN (iso_year_adjust, (tim_p),
	_CONST struct tm *tim_p)
{
  /* Account for fact that tm_year==0 is year 1900.  */
  int leap = isleap (tim_p->tm_year + (YEAR_BASE
				       - (tim_p->tm_year < 0 ? 0 : 2000)));

  /* Pack the yday, wday, and leap year into a single int since there are so
     many disparate cases.  */
#define PACK(yd, wd, lp) (((yd) << 4) + (wd << 1) + (lp))
  switch (PACK (tim_p->tm_yday, tim_p->tm_wday, leap))
    {
    case PACK (0, 5, 0): /* Jan 1 is Fri, not leap.  */
    case PACK (0, 6, 0): /* Jan 1 is Sat, not leap.  */
    case PACK (0, 0, 0): /* Jan 1 is Sun, not leap.  */
    case PACK (0, 5, 1): /* Jan 1 is Fri, leap year.  */
    case PACK (0, 6, 1): /* Jan 1 is Sat, leap year.  */
    case PACK (0, 0, 1): /* Jan 1 is Sun, leap year.  */
    case PACK (1, 6, 0): /* Jan 2 is Sat, not leap.  */
    case PACK (1, 0, 0): /* Jan 2 is Sun, not leap.  */
    case PACK (1, 6, 1): /* Jan 2 is Sat, leap year.  */
    case PACK (1, 0, 1): /* Jan 2 is Sun, leap year.  */
    case PACK (2, 0, 0): /* Jan 3 is Sun, not leap.  */
    case PACK (2, 0, 1): /* Jan 3 is Sun, leap year.  */
      return -1; /* Belongs to last week of previous year.  */
    case PACK (362, 1, 0): /* Dec 29 is Mon, not leap.  */
    case PACK (363, 1, 1): /* Dec 29 is Mon, leap year.  */
    case PACK (363, 1, 0): /* Dec 30 is Mon, not leap.  */
    case PACK (363, 2, 0): /* Dec 30 is Tue, not leap.  */
    case PACK (364, 1, 1): /* Dec 30 is Mon, leap year.  */
    case PACK (364, 2, 1): /* Dec 30 is Tue, leap year.  */
    case PACK (364, 1, 0): /* Dec 31 is Mon, not leap.  */
    case PACK (364, 2, 0): /* Dec 31 is Tue, not leap.  */
    case PACK (364, 3, 0): /* Dec 31 is Wed, not leap.  */
    case PACK (365, 1, 1): /* Dec 31 is Mon, leap year.  */
    case PACK (365, 2, 1): /* Dec 31 is Tue, leap year.  */
    case PACK (365, 3, 1): /* Dec 31 is Wed, leap year.  */
      return 1; /* Belongs to first week of next year.  */
    }
  return 0; /* Belongs to specified year.  */
#undef PACK
}

size_t
_DEFUN (strftime, (s, maxsize, format, tim_p),
	char *s _AND
	size_t maxsize _AND
	_CONST char *format _AND
	_CONST struct tm *tim_p)
{
  size_t count = 0;
  int i;

  for (;;)
    {
      while (*format && *format != '%')
	{
	  if (count < maxsize - 1)
	    s[count++] = *format++;
	  else
	    return 0;
	}

      if (*format == '\0')
	break;

      format++;
      if (*format == 'E' || *format == 'O')
	format++;

      switch (*format)
	{
	case 'a':
	  for (i = 0; i < 3; i++)
	    {
	      if (count < maxsize - 1)
		s[count++] =
		  dname[tim_p->tm_wday][i];
	      else
		return 0;
	    }
	  break;
	case 'A':
	  for (i = 0; i < dname_len[tim_p->tm_wday]; i++)
	    {
	      if (count < maxsize - 1)
		s[count++] =
		  dname[tim_p->tm_wday][i];
	      else
		return 0;
	    }
	  break;
	case 'b':
	case 'h':
	  for (i = 0; i < 3; i++)
	    {
	      if (count < maxsize - 1)
		s[count++] =
		  mname[tim_p->tm_mon][i];
	      else
		return 0;
	    }
	  break;
	case 'B':
	  for (i = 0; i < mname_len[tim_p->tm_mon]; i++)
	    {
	      if (count < maxsize - 1)
		s[count++] =
		  mname[tim_p->tm_mon][i];
	      else
		return 0;
	    }
	  break;
	case 'c':
	  {
	    /* Length is not known because of %C%y, so recurse. */
	    size_t adjust = strftime (&s[count], maxsize - count,
				      "%a %b %e %H:%M:%S %C%y", tim_p);
	    if (adjust > 0)
	      count += adjust;
	    else
	      return 0;
	  }
	  break;
	case 'C':
	  {
	    /* Examples of (tm_year + YEAR_BASE) that show how %Y == %C%y
	       with 32-bit int.
	       %Y		%C		%y
	       2147485547	21474855	47
	       10000		100		00
	       9999		99		99
	       0999		09		99
	       0099		00		99
	       0001		00		01
	       0000		00		00
	       -001		-0		01
	       -099		-0		99
	       -999		-9		99
	       -1000		-10		00
	       -10000		-100		00
	       -2147481748	-21474817	48

	       Be careful of both overflow and sign adjustment due to the
	       asymmetric range of years.
	    */
	    int neg = tim_p->tm_year < -YEAR_BASE;
	    int century = tim_p->tm_year >= 0
	      ? tim_p->tm_year / 100 + YEAR_BASE / 100
	      : abs (tim_p->tm_year + YEAR_BASE) / 100;
            count += snprintf (&s[count], maxsize - count, "%s%.*d",
                               neg ? "-" : "", 2 - neg, century);
            if (count >= maxsize)
              return 0;
	  }
	  break;
	case 'd':
	case 'e':
	  if (count < maxsize - 2)
	    {
	      sprintf (&s[count], *format == 'd' ? "%.2d" : "%2d",
		       tim_p->tm_mday);
	      count += 2;
	    }
	  else
	    return 0;
	  break;
	case 'D':
	case 'x':
	  /* %m/%d/%y */
	  if (count < maxsize - 8)
	    {
	      sprintf (&s[count], "%.2d/%.2d/%.2d",
		       tim_p->tm_mon + 1, tim_p->tm_mday,
		       tim_p->tm_year >= 0 ? tim_p->tm_year % 100
		       : abs (tim_p->tm_year + YEAR_BASE) % 100);
	      count += 8;
	    }
	  else
	    return 0;
	  break;
        case 'F':
	  {
	    /* Length is not known because of %C%y, so recurse. */
	    size_t adjust = strftime (&s[count], maxsize - count,
				      "%C%y-%m-%d", tim_p);
	    if (adjust > 0)
	      count += adjust;
	    else
	      return 0;
	  }
          break;
        case 'g':
	  if (count < maxsize - 2)
	    {
	      /* Be careful of both overflow and negative years, thanks to
		 the asymmetric range of years.  */
	      int adjust = iso_year_adjust (tim_p);
	      int year = tim_p->tm_year >= 0 ? tim_p->tm_year % 100
		: abs (tim_p->tm_year + YEAR_BASE) % 100;
	      if (adjust < 0 && tim_p->tm_year <= -YEAR_BASE)
		adjust = 1;
	      else if (adjust > 0 && tim_p->tm_year < -YEAR_BASE)
		adjust = -1;
	      sprintf (&s[count], "%.2d",
		       ((year + adjust) % 100 + 100) % 100);
	      count += 2;
	    }
	  else
	    return 0;
          break;
        case 'G':
	  {
	    /* See the comments for 'C' and 'Y'; this is a variable length
	       field.  Although there is no requirement for a minimum number
	       of digits, we use 4 for consistency with 'Y'.  */
	    int neg = tim_p->tm_year < -YEAR_BASE;
	    int adjust = iso_year_adjust (tim_p);
	    int century = tim_p->tm_year >= 0
	      ? tim_p->tm_year / 100 + YEAR_BASE / 100
	      : abs (tim_p->tm_year + YEAR_BASE) / 100;
	    int year = tim_p->tm_year >= 0 ? tim_p->tm_year % 100
	      : abs (tim_p->tm_year + YEAR_BASE) % 100;
	    if (adjust < 0 && tim_p->tm_year <= -YEAR_BASE)
	      neg = adjust = 1;
	    else if (adjust > 0 && neg)
	      adjust = -1;
	    year += adjust;
	    if (year == -1)
	      {
		year = 99;
		--century;
	      }
	    else if (year == 100)
	      {
		year = 0;
		++century;
	      }
            count += snprintf (&s[count], maxsize - count, "%s%.*d%.2d",
                               neg ? "-" : "", 2 - neg, century, year);
            if (count >= maxsize)
              return 0;
	  }
          break;
	case 'H':
	case 'k':
	  if (count < maxsize - 2)
	    {
	      sprintf (&s[count], *format == 'k' ? "%2d" : "%.2d",
		       tim_p->tm_hour);
	      count += 2;
	    }
	  else
	    return 0;
	  break;
	case 'I':
	case 'l':
	  if (count < maxsize - 2)
	    {
	      if (tim_p->tm_hour == 0 ||
		  tim_p->tm_hour == 12)
		{
		  s[count++] = '1';
		  s[count++] = '2';
		}
	      else
		{
		  sprintf (&s[count], *format == 'I' ? "%.2d" : "%2d",
			   tim_p->tm_hour % 12);
		  count += 2;
		}
	    }
	  else
	    return 0;
	  break;
	case 'j':
	  if (count < maxsize - 3)
	    {
	      sprintf (&s[count], "%.3d",
		       tim_p->tm_yday + 1);
	      count += 3;
	    }
	  else
	    return 0;
	  break;
	case 'm':
	  if (count < maxsize - 2)
	    {
	      sprintf (&s[count], "%.2d",
		       tim_p->tm_mon + 1);
	      count += 2;
	    }
	  else
	    return 0;
	  break;
	case 'M':
	  if (count < maxsize - 2)
	    {
	      sprintf (&s[count], "%.2d",
		       tim_p->tm_min);
	      count += 2;
	    }
	  else
	    return 0;
	  break;
	case 'n':
	  if (count < maxsize - 1)
	    s[count++] = '\n';
	  else
	    return 0;
	  break;
	case 'p':
	  if (count < maxsize - 2)
	    {
	      if (tim_p->tm_hour < 12)
		s[count++] = 'A';
	      else
		s[count++] = 'P';

	      s[count++] = 'M';
	    }
	  else
	    return 0;
	  break;
	case 'r':
	  if (count < maxsize - 11)
	    {
	      if (tim_p->tm_hour == 0 ||
		  tim_p->tm_hour == 12)
		{
		  s[count++] = '1';
		  s[count++] = '2';
		}
	      else
		{
		  sprintf (&s[count], "%.2d", tim_p->tm_hour % 12);
		  count += 2;
		}
	      s[count++] = ':';
	      sprintf (&s[count], "%.2d",
		       tim_p->tm_min);
	      count += 2;
	      s[count++] = ':';
	      sprintf (&s[count], "%.2d",
		       tim_p->tm_sec);
	      count += 2;
	      s[count++] = ' ';
	      if (tim_p->tm_hour < 12)
		s[count++] = 'A';
	      else
		s[count++] = 'P';

	      s[count++] = 'M';
	    }
	  else
	    return 0;
	  break;
        case 'R':
          if (count < maxsize - 5)
            {
              sprintf (&s[count], "%.2d:%.2d", tim_p->tm_hour, tim_p->tm_min);
              count += 5;
            }
          else
            return 0;
          break;
	case 'S':
	  if (count < maxsize - 2)
	    {
	      sprintf (&s[count], "%.2d",
		       tim_p->tm_sec);
	      count += 2;
	    }
	  else
	    return 0;
	  break;
	case 't':
	  if (count < maxsize - 1)
	    s[count++] = '\t';
	  else
	    return 0;
	  break;
        case 'T':
        case 'X':
          if (count < maxsize - 8)
            {
              sprintf (&s[count], "%.2d:%.2d:%.2d", tim_p->tm_hour,
                       tim_p->tm_min, tim_p->tm_sec);
              count += 8;
            }
          else
            return 0;
          break;
        case 'u':
          if (count < maxsize - 1)
            {
              if (tim_p->tm_wday == 0)
                s[count++] = '7';
              else
                s[count++] = '0' + tim_p->tm_wday;
            }
          else
            return 0;
          break;
	case 'U':
	  if (count < maxsize - 2)
	    {
	      sprintf (&s[count], "%.2d",
		       (tim_p->tm_yday + 7 -
			tim_p->tm_wday) / 7);
	      count += 2;
	    }
	  else
	    return 0;
	  break;
        case 'V':
	  if (count < maxsize - 2)
	    {
	      int adjust = iso_year_adjust (tim_p);
	      int wday = (tim_p->tm_wday) ? tim_p->tm_wday - 1 : 6;
	      int week = (tim_p->tm_yday + 10 - wday) / 7;
	      if (adjust > 0)
		week = 1;
	      else if (adjust < 0)
		/* Previous year has 53 weeks if current year starts on
		   Fri, and also if current year starts on Sat and
		   previous year was leap year.  */
		week = 52 + (4 >= (wday - tim_p->tm_yday
				   - isleap (tim_p->tm_year
					     + (YEAR_BASE - 1
						- (tim_p->tm_year < 0
						   ? 0 : 2000)))));
	      sprintf (&s[count], "%.2d", week);
	      count += 2;
	    }
	  else
	    return 0;
          break;
	case 'w':
	  if (count < maxsize - 1)
            s[count++] = '0' + tim_p->tm_wday;
	  else
	    return 0;
	  break;
	case 'W':
	  if (count < maxsize - 2)
	    {
	      int wday = (tim_p->tm_wday) ? tim_p->tm_wday - 1 : 6;
	      sprintf (&s[count], "%.2d",
		       (tim_p->tm_yday + 7 - wday) / 7);
	      count += 2;
	    }
	  else
	    return 0;
	  break;
	case 'y':
	  if (count < maxsize - 2)
	    {
	      /* Be careful of both overflow and negative years, thanks to
		 the asymmetric range of years.  */
	      int year = tim_p->tm_year >= 0 ? tim_p->tm_year % 100
		: abs (tim_p->tm_year + YEAR_BASE) % 100;
	      sprintf (&s[count], "%.2d", year);
	      count += 2;
	    }
	  else
	    return 0;
	  break;
	case 'Y':
	  {
	    /* Length is not known because of %C%y, so recurse. */
	    size_t adjust = strftime (&s[count], maxsize - count,
				      "%C%y", tim_p);
	    if (adjust > 0)
	      count += adjust;
	    else
	      return 0;
	  }
	  break;
        case 'z':
#ifndef _WIN32_WCE
          if (tim_p->tm_isdst >= 0)
            {
	      if (count < maxsize - 5)
		{
		  long offset;
		  __tzinfo_type *tz = __gettzinfo ();
		  TZ_LOCK;
		  /* The sign of this is exactly opposite the envvar TZ.  We
		     could directly use the global _timezone for tm_isdst==0,
		     but have to use __tzrule for daylight savings.  */
		  offset = -tz->__tzrule[tim_p->tm_isdst > 0].offset;
		  TZ_UNLOCK;
		  sprintf (&s[count], "%+03ld%.2ld", offset / SECSPERHOUR,
			   labs (offset / SECSPERMIN) % 60L);
		  count += 5;
		}
	      else
		return 0;
            }
          break;
#endif
	case 'Z':
	  if (tim_p->tm_isdst >= 0)
	    {
	      int size;
	      TZ_LOCK;
	      size = strlen(_tzname[tim_p->tm_isdst > 0]);
	      for (i = 0; i < size; i++)
		{
		  if (count < maxsize - 1)
		    s[count++] = _tzname[tim_p->tm_isdst > 0][i];
		  else
		    {
		      TZ_UNLOCK;
		      return 0;
		    }
		}
	      TZ_UNLOCK;
	    }
	  break;
	case '%':
	  if (count < maxsize - 1)
	    s[count++] = '%';
	  else
	    return 0;
	  break;
	}
      if (*format)
	format++;
      else
	break;
    }
  if (maxsize)
    s[count] = '\0';

  return count;
}