time.c

它通过提供glibc兼容使得应用程序移植到较小的c 库时相当得容易. 它能够应用到带虚拟存储的Linux和uClinux上.在大多数带MMU部件的平台上为使它更加紧凑,它也能够编译成共享库.uClib

				if (((i&128) + field_val) == 0) { /* mod 12? == 0 */
					field_val = j; /* set to 12 */
				}
			}
			field_val += (i & 1);
			if ((i & 8) && !field_val) {
				field_val += 7;
			}
		}
		
		if ((code & MASK_SPEC) == STRING_SPEC) {
			o_count = SIZE_MAX;
			field_val += spec[STRINGS_NL_ITEM_START + (code & 0xf)];
			o = nl_langinfo(_NL_ITEM(LC_TIME, field_val));
		} else {
			o_count = ((i >> 1) & 3) + 1;
			o = buf + o_count;
			do {
				*(char *)(--o) = '0' + (field_val % 10);
				field_val /= 10;
			} while (o > buf);
			if (*buf == '0') {
				*buf = ' ' + (i & 16);
			}
		}
	}

 OUTPUT:
	++p;
	while (o_count && count && *o) {
		*s++ = *o++;
		--o_count;
		--count;
	}
	goto LOOP;
}

#endif
/**********************************************************************/
#ifdef L_strptime

/* TODO:
 * 1) %l and %k are space-padded, so "%l" by itself fails while " %l" succeeds.
 *    Both work for glibc.  So, should we always strip spaces?
 * 2) %Z
 */

/* Notes:
 * There are several differences between this strptime and glibc's strptime.
 * 1) glibc strips leading space before numeric conversions.
 * 2) glibc will read fields without whitespace in between.  SUSv3 states
 *    that you must have whitespace between conversion operators.  Besides,
 *    how do you know how long a number should be if there are leading 0s?
 * 3) glibc attempts to compute some the struct tm fields based on the
 *    data retrieved; tm_wday in particular.  I don't as I consider it
 *     another glibc attempt at mind-reading...
 */

#define NO_E_MOD		0x80
#define NO_O_MOD		0x40

#define ILLEGAL_SPEC	0x3f

#define INT_SPEC		0x00	/* must be 0x00!! */
#define STRING_SPEC		0x10	/* must be 0x10!! */
#define CALC_SPEC		0x20
#define STACKED_SPEC	0x30

#define MASK_SPEC		0x30

/* Warning: Assumes ASCII values! (as do lots of other things in the lib...) */
static const unsigned char spec[] = {
	/* A */		0x02 |  STRING_SPEC | NO_E_MOD | NO_O_MOD,
	/* B */		0x01 |  STRING_SPEC | NO_E_MOD | NO_O_MOD,
	/* C */		0x08 |     INT_SPEC            | NO_O_MOD,
	/* D */		0x01 | STACKED_SPEC | NO_E_MOD | NO_O_MOD,
	/* E */		       ILLEGAL_SPEC | NO_E_MOD | NO_O_MOD,
	/* F */		0x02 | STACKED_SPEC | NO_E_MOD | NO_O_MOD, /* glibc */
	/* G */		0x0f |     INT_SPEC | NO_E_MOD | NO_O_MOD, /* glibc */
	/* H */		0x06 |     INT_SPEC | NO_E_MOD,
	/* I */		0x07 |     INT_SPEC | NO_E_MOD,
	/* J */		       ILLEGAL_SPEC | NO_E_MOD | NO_O_MOD,
	/* K */		       ILLEGAL_SPEC | NO_E_MOD | NO_O_MOD,
	/* L */		       ILLEGAL_SPEC | NO_E_MOD | NO_O_MOD,
	/* M */		0x04 |     INT_SPEC | NO_E_MOD,
	/* N */		       ILLEGAL_SPEC | NO_E_MOD | NO_O_MOD,
	/* O */		       ILLEGAL_SPEC | NO_E_MOD | NO_O_MOD,
	/* P */		0x00 |  STRING_SPEC | NO_E_MOD | NO_O_MOD, /* glibc */
	/* Q */		       ILLEGAL_SPEC | NO_E_MOD | NO_O_MOD,
	/* R */		0x03 | STACKED_SPEC | NO_E_MOD | NO_O_MOD,
	/* S */		0x05 |     INT_SPEC | NO_E_MOD,
	/* T */		0x04 | STACKED_SPEC | NO_E_MOD | NO_O_MOD,
	/* U */		0x0c |     INT_SPEC | NO_E_MOD,
	/* V */		0x0d |     INT_SPEC | NO_E_MOD | NO_O_MOD, /* glibc */
	/* W */		0x0c |     INT_SPEC | NO_E_MOD,
	/* X */		0x0a | STACKED_SPEC            | NO_O_MOD,
	/* Y */		0x0a |     INT_SPEC            | NO_O_MOD,
	/* Z */		0x02 |    CALC_SPEC | NO_E_MOD | NO_O_MOD, /* glibc */

	/* WARNING! This assumes orderings:
	 *    AM,PM
	 *    ABDAY_1-ABDAY-7,DAY_1-DAY_7
	 *    ABMON_1-ABMON_12,MON_1-MON12
	 * Also, there are exactly 6 bytes between 'Z' and 'a'.
	 */
#define STRINGS_NL_ITEM_START (26)
	_NL_ITEM_INDEX(AM_STR),		/* p (P) */
	_NL_ITEM_INDEX(ABMON_1),	/* B, b */
	_NL_ITEM_INDEX(ABDAY_1),	/* A, a */
	2,
	24,
	14,

	/* a */		0x02 |  STRING_SPEC | NO_E_MOD | NO_O_MOD,
	/* b */		0x01 |  STRING_SPEC | NO_E_MOD | NO_O_MOD,
	/* c */		0x08 | STACKED_SPEC            | NO_O_MOD,
	/* d */		0x00 |     INT_SPEC | NO_E_MOD,
	/* e */		0x00 |     INT_SPEC | NO_E_MOD,
	/* f */		       ILLEGAL_SPEC | NO_E_MOD | NO_O_MOD,
	/* g */		0x0e |     INT_SPEC | NO_E_MOD | NO_O_MOD, /* glibc */
	/* h */		0x01 |  STRING_SPEC | NO_E_MOD | NO_O_MOD,
	/* i */		       ILLEGAL_SPEC | NO_E_MOD | NO_O_MOD,
	/* j */		0x01 |     INT_SPEC | NO_E_MOD | NO_O_MOD,
	/* k */		0x06 |     INT_SPEC | NO_E_MOD,            /* glibc */
	/* l */		0x07 |     INT_SPEC | NO_E_MOD,            /* glibc */
	/* m */		0x02 |     INT_SPEC | NO_E_MOD,
	/* n */		0x00 | STACKED_SPEC | NO_E_MOD | NO_O_MOD,
	/* o */		       ILLEGAL_SPEC | NO_E_MOD | NO_O_MOD,
	/* p */		0x00 |  STRING_SPEC | NO_E_MOD | NO_O_MOD,
	/* q */		       ILLEGAL_SPEC | NO_E_MOD | NO_O_MOD,
	/* r */		0x0b | STACKED_SPEC | NO_E_MOD | NO_O_MOD,
	/* s */		0x00 |    CALC_SPEC | NO_E_MOD | NO_O_MOD, /* glibc */
	/* t */		0x00 | STACKED_SPEC | NO_E_MOD | NO_O_MOD,
	/* u */		0x0b |     INT_SPEC | NO_E_MOD | NO_O_MOD, /* glibc */
	/* v */		       ILLEGAL_SPEC | NO_E_MOD | NO_O_MOD,
	/* w */		0x03 |     INT_SPEC | NO_E_MOD,
	/* x */		0x09 | STACKED_SPEC            | NO_O_MOD,
	/* y */		0x09 |     INT_SPEC,
	/* z */		0x01 |    CALC_SPEC | NO_E_MOD | NO_O_MOD, /* glibc */

#define INT_FIELD_START (26+6+26)
	/* (field #) << 3  + lower bound (0|1) + correction 0:none, 2:-1, 4:-1900
	 * followed by upper bound prior to correction with 1=>366 and 2=>9999. */
	/* d, e */	(3 << 3) + 1 + 0, 31,
	/* j */		(7 << 3) + 1 + 2, /* 366 */ 1,
	/* m */		(4 << 3) + 1 + 2, 12,
	/* w */		(6 << 3) + 0 + 0, 6,
	/* M */		(1 << 3) + 0 + 0, 59,
	/* S */		0        + 0 + 0, 60,
	/* H (k) */	(2 << 3) + 0 + 0, 23,
	/* I (l) */	(9 << 3) + 1 + 0, 12, /* goes with 8 -- am/pm */
	/* C */		(10<< 3) + 0 + 0, 99,
	/* y */		(11<< 3) + 0 + 0, 99,
	/* Y */		(5 << 3) + 0 + 4, /* 9999 */ 2,
	/* u */		(6 << 3) + 1 + 0, 7,
	/* The following are processed and range-checked, but ignored otherwise. */
	/* U, W */	(12<< 3) + 0 + 0, 53,
	/* V */		(12<< 3) + 1 + 0, 53,
	/* g */		(12<< 3) + 0 + 0, 99,
	/* G */		(12<< 3) + 0 /*+ 4*/, /* 9999 */ 2, /* Note: -1 or 10000? */

#define STACKED_STRINGS_START (INT_FIELD_START+32)
	5, 6, 14, 22, 27,			/* 5 - offsets from offset-count to strings */
	' ', 0,						/* 2 - %n or %t */
	'%', 'm', '/', '%', 'd', '/', '%', 'y', 0, /* 9 - %D */
	'%', 'Y', '-', '%', 'm', '-', '%', 'd', 0, /* 9 - %F (glibc extension) */
	'%', 'H', ':', '%', 'M', 0,	/* 6 - %R*/
	'%', 'H', ':', '%', 'M', ':', '%', 'S', 0, /* 9 - %T */

#define STACKED_STRINGS_NL_ITEM_START (STACKED_STRINGS_START + 40)
	_NL_ITEM_INDEX(D_T_FMT),	/* c */
	_NL_ITEM_INDEX(D_FMT),		/* x */
	_NL_ITEM_INDEX(T_FMT),		/* X */
	_NL_ITEM_INDEX(T_FMT_AMPM), /* r */
#ifdef ENABLE_ERA_CODE
	_NL_ITEM_INDEX(ERA_D_T_FMT), /* Ec */
	_NL_ITEM_INDEX(ERA_D_FMT),	/* Ex */
	_NL_ITEM_INDEX(ERA_T_FMT),	/* EX */
#endif
};

#define MAX_PUSH 4

char *strptime(const char *__restrict buf, const char *__restrict format,
			   struct tm *__restrict tm)
{
	register const char *p;
	char *o;
	const char *stack[MAX_PUSH];
	int i, j, lvl;
	int fields[13];
	unsigned char mod;
	unsigned char code;

	i = 0;
	do {
		fields[i] = INT_MIN;
	} while (++i < 13);

	lvl = 0;
	p = format;

 LOOP:
	if (!*p) {
		if (lvl == 0) {			/* Done. */
			if (fields[6] == 7) { /* Cleanup for %u here since just once. */
				fields[6] = 0;	/* Don't use mod in case unset. */
			}

			i = 0;
			do {				/* Store the values into tm. */
				((int *) tm)[i] = fields[i];
			} while (++i < 8);

			return (char *) buf; /* Success. */
		}
		p = stack[--lvl];
		goto LOOP;
	}

	if ((*p == '%') && (*++p != '%')) {
		mod = ILLEGAL_SPEC;
		if ((*p == 'O') || (*p == 'E')) { /* Modifier? */
			mod |= ((*p == 'O') ? NO_O_MOD : NO_E_MOD);
			++p;
		}

		if (!*p
			|| (((unsigned char)(((*p) | 0x20) - 'a')) >= 26)
			|| (((code = spec[(int)(*p - 'A')]) & mod) >= ILLEGAL_SPEC)
			) {
			return NULL;		/* Illegal spec. */
		}

		if ((code & MASK_SPEC) == STACKED_SPEC) {
			if (lvl == MAX_PUSH) {
				return NULL;	/* Stack full so treat as illegal spec. */
			}
			stack[lvl++] = ++p;
			if ((code &= 0xf) < 8) {
				p = ((const char *) spec) + STACKED_STRINGS_START + code;
				p += *((unsigned char *)p);
				goto LOOP;
			}

			p = ((const char *) spec) + STACKED_STRINGS_NL_ITEM_START
				+ (code & 7);
#ifdef ENABLE_ERA_CODE
			if ((mod & NO_E_MOD) /* Actually, this means E modifier present. */
				&& (*(o = nl_langinfo(_NL_ITEM(LC_TIME,
											   (int)(((unsigned char *)p)[4]))
									  )))
				) {
				p = o;
				goto LOOP;
			}
#endif
			p = nl_langinfo(_NL_ITEM(LC_TIME,
									 (int)(*((unsigned char *)p))));
			goto LOOP;
		}

		++p;

		if ((code & MASK_SPEC) == STRING_SPEC) {
			code &= 0xf;
			j = spec[STRINGS_NL_ITEM_START + 3 + code];
			i = _NL_ITEM(LC_TIME, spec[STRINGS_NL_ITEM_START + code]);
			/* Go backwards to check full names before abreviations. */
			do {
				--j;
				o = nl_langinfo(i+j);
				if (!strncasecmp(buf,o,strlen(o)) && *o) { /* Found a match. */
					do {
						++buf;
					} while (*++o);
					if (!code) { /* am/pm */
						fields[8] = j * 12;
						if (fields[9] >= 0) { /* We have a previous %I or %l. */
							fields[2] = fields[9] + fields[8];
						}
					} else {	/* day (4) or month (6) */
						fields[2 + (code << 1)]
							= j % (spec[STRINGS_NL_ITEM_START + 3 + code] >> 1);
					}
					goto LOOP;
				}
			} while (j);
			return NULL;		/* Failed to match. */
		}

		if ((code & MASK_SPEC) == CALC_SPEC) {
			if ((code &= 0xf) < 1) { /* s or z*/
				time_t t;

				o = (char *) buf;
				i = errno;
				__set_errno(0);
				if (!isspace(*buf)) { /* Signal an error if whitespace. */
#ifdef TIME_T_IS_UNSIGNED
					t = strtoul(buf, &o, 10);
#else
					t = strtol(buf, &o, 10);
#endif
				}
				if ((o == buf) || errno) { /* Not a number or overflow. */
					return NULL;
				}
				__set_errno(i);	/* Restore errno. */
				buf = o;

				if (!code) {	/* s */
					localtime_r(&t, tm); /* TODO: check for failure? */
					i = 0;
					do {		/* Now copy values from tm to fields. */
						 fields[i] = ((int *) tm)[i];
					} while (++i < 8);
				}
			}
			/* TODO: glibc treats %Z as a nop.  For now, do the same. */
			goto LOOP;
		}

		assert((code & MASK_SPEC) == INT_SPEC);
		{
			register const unsigned char *x;
			code &= 0xf;
			x = spec + INT_FIELD_START + (code << 1);
			if ((j = x[1]) < 3) { /* upper bound (inclusive) */
				j = ((j==1) ? 366 : 9999);
			}
			i = -1;
			while (isdigit(*buf)) {
				if (i < 0) {
					i = 0;
				}
				if ((i = 10*i + (*buf - '0')) > j) { /* Overflow. */
					return NULL;
				}
				++buf;
			}
			if (i < (*x & 1)) {	/* This catches no-digit case too. */
				return NULL;
			}
			if (*x & 2) {
				--i;
			}
			if (*x & 4) {
				i -= 1900;
			}

			if (*x == (9 << 3) + 1 + 0) { /* %I or %l */
				if (i == 12) {
					i = 0;
				}
				if (fields[8] >= 0) { /* We have a previous %p or %P. */
					fields[2] = i + fields[8];
				}
			}

			fields[(*x) >> 3] = i;

			if (((unsigned char)(*x - (10<< 3) + 0 + 0)) <= 8) { /* %C or %y */
				if ((j = fields[10]) < 0) {	/* No %C, so i must be %y data. */
					if (i <= 68) { /* Map [0-68] to 2000+i */
						i += 100;
					}
				} else {		/* Have %C data, but what about %y? */
					if ((i = fields[11]) < 0) {	/* No %y data. */
						i = 0;	/* Treat %y val as 0 following glibc's example. */
					}
					i += 100*(j - 19);
				}
				fields[5] = i;
			}
		}
		goto LOOP;
	} else if (isspace(*p)) {
		++p;
		while (isspace(*buf)) {
			++buf;
		}
		goto LOOP;
	} else if (*buf++ == *p++) {
		goto LOOP;
	}
	return NULL;
}

#endif
/**********************************************************************/
#ifdef L_time

#ifndef __BCC__
#error The uClibc version of time is in sysdeps/linux/common.
#endif

time_t time(register time_t *tloc)
{
	struct timeval tv;
	register struct timeval *p = &tv;

	gettimeofday(p, NULL);		/* This should never fail... */

	if (tloc) {
		*tloc = p->tv_sec;
	}

	return p->tv_sec;
}

#endif
/**********************************************************************/
#ifdef L_tzset

static const char vals[] = {
	'T', 'Z', 0,				/* 3 */
	'U', 'T', 'C', 0,			/* 4 */
	25, 60, 60, 1,				/* 4 */
	'.', 1,						/* M */
	5, '.', 1,
	6,  0,  0,					/* Note: overloaded for non-M non-J case... */
	0, 1, 0,					/* J */
	',', 'M',      '4', '.', '1', '.', '0',
	',', 'M', '1', '0', '.', '5', '.', '0', 0
};

#define TZ    vals
#define UTC   (vals + 3)
#define RANGE (vals + 7)
#define RULE  (vals + 11 - 1)
#define DEFAULT_RULES (vals + 22)

/* Initialize to UTC. */
int daylight = 0;
long timezone = 0;
char *tzname[2] = { (char *) UTC, (char *) (UTC-1) };

#ifdef __UCLIBC_HAS_THREADS__
pthread_mutex_t _time_tzlock = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
#endif

rule_struct _time_tzinfo[2];

static const char *getoffset(register const char *e, long *pn)
{
	register const char *s = RANGE-1;
	long n;
	int f;

	n = 0;
	f = -1;
	do {
		++s;
		if (isdigit(*e)) {
			f = *e++ - '0';
		}
		if (isdigit(*e)) {
			f = 10 * f + (*e++ - '0');
		}
		if (((unsigned int)f) >= *s) {
			return NULL;
		}
		n = (*s) * n + f;
		f = 0;
		if (*e == ':') {
			++e;
			--f;
		}
	} while (*s > 1);

	*pn = n;
	return e;
}

static const char *getnumber(register const char *e, int *pn)
{
#ifdef __BCC__
	/* bcc can optimize the counter if it thinks it is a pointer... */
	register const char *n = (const char *) 3;
	int f;

	f = 0;
	while (n && isdigit(*e)) {
		f = 10 * f + (*e++ - '0');
		--n;
	}

	*pn = f;
	return (n == (const char *) 3) ? NULL : e;
#else  /* __BCC__ */
	int n, f;

	n = 3;
	f = 0;
	while (n && isdigit(*e)) {
		f = 10 * f + (*e++ - '0');
		--n;
	}

	*pn = f;
	return (n == 3) ? NULL : e;
#endif /* __BCC__ */
}

#ifdef __TIME_TZ_FILE

#ifdef __TIME_TZ_FILE_ONCE
static int TZ_file_read;  		/* Let BSS initialization set this to 0. */
#endif /* __TIME_TZ_FILE_ONCE */