misc.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

			if (p[-1] == (0x80 | '?')
			    && do_gmatch(s, se, prest, pe, isfile))
				return 1;
			for (psub = p; ; psub = pnext) {
				pnext = pat_scan(psub, pe, 1);
				srest = prest == pe ? se : s;
				for (; srest <= se; srest++) {
					if (do_gmatch(s, srest,
						      psub, pnext - 2, isfile)
					    && do_gmatch(srest, se,
							 prest, pe, isfile))
						return 1;
				}
				if (pnext == prest)
					break;
			}
			return 0;

		  case 0x80|'!': /* matches none of the patterns */
			if (!(prest = pat_scan(p, pe, 0)))
				return 0;
			s--;
			for (srest = s; srest <= se; srest++) {
				int matched = 0;

				for (psub = p; ; psub = pnext) {
					pnext = pat_scan(psub, pe, 1);
					if (do_gmatch(s, srest,
						      psub, pnext - 2, isfile))
					{
						matched = 1;
						break;
					}
					if (pnext == prest)
						break;
				}
				if (!matched && do_gmatch(srest, se,
							  prest, pe, isfile))
					return 1;
			}
			return 0;

		  default:
			if (sc != p[-1])
				return 0;
			break;
		}
	}
	return s == se;
}

static const unsigned char *
cclass(p, sub)
	const unsigned char *p;
	register int sub;
{
	register int c, d, not, found = 0;
	const unsigned char *orig_p = p;

	if ((not = (ISMAGIC(*p) && *++p == NOT)))
		p++;
	do {
		c = *p++;
		if (ISMAGIC(c)) {
			c = *p++;
			if ((c & 0x80) && !ISMAGIC(c)) {
				c &= 0x7f;/* extended pattern matching: *+?@! */
				/* XXX the ( char isn't handled as part of [] */
				if (c == ' ') /* simile for @: plain (..) */
					c = '(' /*)*/;
			}
		}
		if (c == '\0')
			/* No closing ] - act as if the opening [ was quoted */
			return sub == '[' ? orig_p : NULL;
		if (ISMAGIC(p[0]) && p[1] == '-'
		    && (!ISMAGIC(p[2]) || p[3] != ']'))
		{
			p += 2; /* MAGIC- */
			d = *p++;
			if (ISMAGIC(d)) {
				d = *p++;
				if ((d & 0x80) && !ISMAGIC(d))
					d &= 0x7f;
			}
			/* POSIX says this is an invalid expression */
			if (c > d)
				return NULL;
		} else
			d = c;
		if (c == sub || (c <= sub && sub <= d))
			found = 1;
	} while (!(ISMAGIC(p[0]) && p[1] == ']'));

	return (found != not) ? p+2 : NULL;
}

/* Look for next ) or | (if match_sep) in *(foo|bar) pattern */
const unsigned char *
pat_scan(p, pe, match_sep)
	const unsigned char *p;
	const unsigned char *pe;
	int match_sep;
{
	int nest = 0;

	for (; p < pe; p++) {
		if (!ISMAGIC(*p))
			continue;
		if ((*++p == /*(*/ ')' && nest-- == 0)
		    || (*p == '|' && match_sep && nest == 0))
			return ++p;
		if ((*p & 0x80) && strchr("*+?@! ", *p & 0x7f))
			nest++;
	}
	return (const unsigned char *) 0;
}


/* -------- qsort.c -------- */

/*
 * quick sort of array of generic pointers to objects.
 */
static void qsort1 ARGS((void **base, void **lim, int (*f)(void *, void *)));

void
qsortp(base, n, f)
	void **base;				/* base address */
	size_t n;				/* elements */
	int (*f) ARGS((void *, void *));	/* compare function */
{
	qsort1(base, base + n, f);
}

#define	swap2(a, b)	{\
	register void *t; t = *(a); *(a) = *(b); *(b) = t;\
}
#define	swap3(a, b, c)	{\
	register void *t; t = *(a); *(a) = *(c); *(c) = *(b); *(b) = t;\
}

static void
qsort1(base, lim, f)
	void **base, **lim;
	int (*f) ARGS((void *, void *));
{
	register void **i, **j;
	register void **lptr, **hptr;
	size_t n;
	int c;

  top:
	n = (lim - base) / 2;
	if (n == 0)
		return;
	hptr = lptr = base+n;
	i = base;
	j = lim - 1;

	for (;;) {
		if (i < lptr) {
			if ((c = (*f)(*i, *lptr)) == 0) {
				lptr --;
				swap2(i, lptr);
				continue;
			}
			if (c < 0) {
				i += 1;
				continue;
			}
		}

	  begin:
		if (j > hptr) {
			if ((c = (*f)(*hptr, *j)) == 0) {
				hptr ++;
				swap2(hptr, j);
				goto begin;
			}
			if (c > 0) {
				if (i == lptr) {
					hptr ++;
					swap3(i, hptr, j);
					i = lptr += 1;
					goto begin;
				}
				swap2(i, j);
				j -= 1;
				i += 1;
				continue;
			}
			j -= 1;
			goto begin;
		}

		if (i == lptr) {
			if (lptr-base >= lim-hptr) {
				qsort1(hptr+1, lim, f);
				lim = lptr;
			} else {
				qsort1(base, lptr, f);
				base = hptr+1;
			}
			goto top;
		}

		lptr -= 1;
		swap3(j, lptr, i);
		j = hptr -= 1;
	}
}

int
xstrcmp(p1, p2)
	void *p1, *p2;
{
	return (strcmp((char *)p1, (char *)p2));
}

/* Initialize a Getopt structure */
void
ksh_getopt_reset(go, flags)
	Getopt *go;
	int flags;
{
	go->optind = 1;
	go->optarg = (char *) 0;
	go->p = 0;
	go->flags = flags;
	go->info = 0;
	go->buf[1] = '\0';
}


/* getopt() used for shell built-in commands, the getopts command, and
 * command line options.
 * A leading ':' in options means don't print errors, instead return '?'
 * or ':' and set go->optarg to the offending option character.
 * If GF_ERROR is set (and option doesn't start with :), errors result in
 * a call to bi_errorf().
 *
 * Non-standard features:
 *	- ';' is like ':' in options, except the argument is optional
 *	  (if it isn't present, optarg is set to 0).
 *	  Used for 'set -o'.
 *	- ',' is like ':' in options, except the argument always immediately
 *	  follows the option character (optarg is set to the null string if
 *	  the option is missing).
 *	  Used for 'read -u2', 'print -u2' and fc -40.
 *	- '#' is like ':' in options, expect that the argument is optional
 *	  and must start with a digit.  If the argument doesn't start with a
 *	  digit, it is assumed to be missing and normal option processing
 *	  continues (optarg is set to 0 if the option is missing).
 *	  Used for 'typeset -LZ4'.
 *	- accepts +c as well as -c IF the GF_PLUSOPT flag is present.  If an
 *	  option starting with + is accepted, the GI_PLUS flag will be set
 *	  in go->info.
 */
int
ksh_getopt(argv, go, options)
	char **argv;
	Getopt *go;
	const char *options;
{
	char c;
	char *o;

	if (go->p == 0 || (c = argv[go->optind - 1][go->p]) == '\0') {
		char *arg = argv[go->optind], flag = arg ? *arg : '\0';

		go->p = 1;
		if (flag == '-' && arg[1] == '-' && arg[2] == '\0') {
			go->optind++;
			go->p = 0;
			go->info |= GI_MINUSMINUS;
			return EOF;
		}
		if (arg == (char *) 0
		    || ((flag != '-' ) /* neither a - nor a + (if + allowed) */
			&& (!(go->flags & GF_PLUSOPT) || flag != '+'))
		    || (c = arg[1]) == '\0')
		{
			go->p = 0;
			return EOF;
		}
		go->optind++;
		go->info &= ~(GI_MINUS|GI_PLUS);
		go->info |= flag == '-' ? GI_MINUS : GI_PLUS;
	}
	go->p++;
	if (c == '?' || c == ':' || c == ';' || c == ',' || c == '#'
	    || !(o = strchr(options, c)))
	{
		if (options[0] == ':') {
			go->buf[0] = c;
			go->optarg = go->buf;
		} else {
			warningf(TRUE, "%s%s-%c: unknown option",
				(go->flags & GF_NONAME) ? "" : argv[0],
				(go->flags & GF_NONAME) ? "" : ": ", c);
			if (go->flags & GF_ERROR)
				bi_errorf(null);
		}
		return '?';
	}
	/* : means argument must be present, may be part of option argument
	 *   or the next argument
	 * ; same as : but argument may be missing
	 * , means argument is part of option argument, and may be null.
	 */
	if (*++o == ':' || *o == ';') {
		if (argv[go->optind - 1][go->p])
			go->optarg = argv[go->optind - 1] + go->p;
		else if (argv[go->optind])
			go->optarg = argv[go->optind++];
		else if (*o == ';')
			go->optarg = (char *) 0;
		else {
			if (options[0] == ':') {
				go->buf[0] = c;
				go->optarg = go->buf;
				return ':';
			}
			warningf(TRUE, "%s%s-`%c' requires argument",
				(go->flags & GF_NONAME) ? "" : argv[0],
				(go->flags & GF_NONAME) ? "" : ": ", c);
			if (go->flags & GF_ERROR)
				bi_errorf(null);
			return '?';
		}
		go->p = 0;
	} else if (*o == ',') {
		/* argument is attatched to option character, even if null */
		go->optarg = argv[go->optind - 1] + go->p;
		go->p = 0;
	} else if (*o == '#') {
		/* argument is optional and may be attatched or unattatched
		 * but must start with a digit.  optarg is set to 0 if the
		 * argument is missing.
		 */
		if (argv[go->optind - 1][go->p]) {
			if (digit(argv[go->optind - 1][go->p])) {
				go->optarg = argv[go->optind - 1] + go->p;
				go->p = 0;
			} else
				go->optarg = (char *) 0;;
		} else {
			if (argv[go->optind] && digit(argv[go->optind][0])) {
				go->optarg = argv[go->optind++];
				go->p = 0;
			} else
				go->optarg = (char *) 0;;
		}
	}
	return c;
}

/* print variable/alias value using necessary quotes
 * (POSIX says they should be suitable for re-entry...)
 * No trailing newline is printed.
 */
void
print_value_quoted(s)
	const char *s;
{
	const char *p;
	int inquote = 0;

	/* Test if any quotes are needed */
	for (p = s; *p; p++)
		if (ctype(*p, C_QUOTE))
			break;
	if (!*p) {
		shprintf("%s", s);
		return;
	}
	for (p = s; *p; p++) {
		if (*p == '\'') {
			shprintf("'\\'" + 1 - inquote);
			inquote = 0;
		} else {
			if (!inquote) {
				shprintf("'");
				inquote = 1;
			}
			shf_putc(*p, shl_stdout);
		}
	}
	if (inquote)
		shprintf("'");
}

/* Print things in columns and rows - func() is called to format the ith
 * element
 */
void
print_columns(shf, n, func, arg, max_width)
	struct shf *shf;
	int n;
	char *(*func) ARGS((void *, int, char *, int));
	void *arg;
	int max_width;
{
	char *str = (char *) alloc(max_width + 1, ATEMP);
	int i;
	int r, c;
	int rows, cols;
	int nspace;

	/* max_width + 1 for the space.  Note that no space
	 * is printed after the last column to avoid problems
	 * with terminals that have auto-wrap.
	 */
	cols = x_cols / (max_width + 1);
	if (!cols)
		cols = 1;
	rows = (n + cols - 1) / cols;
	if (n && cols > rows) {
		int tmp = rows;

		rows = cols;
		cols = tmp;
		if (rows > n)
			rows = n;
	}

	nspace = (x_cols - max_width * cols) / cols;
	if (nspace <= 0)
		nspace = 1;
	for (r = 0; r < rows; r++) {
		for (c = 0; c < cols; c++) {
			i = c * rows + r;
			if (i < n) {
				shf_fprintf(shf, "%-*s",
					max_width,
					(*func)(arg, i, str, max_width + 1));
				if (c + 1 < cols)
					shf_fprintf(shf, "%*s", nspace, null);
			}
		}
		shf_putchar('\n', shf);
	}
	afree(str, ATEMP);
}

/* Strip any nul bytes from buf - returns new length (nbytes - # of nuls) */
int
strip_nuls(buf, nbytes)
	char *buf;
	int nbytes;
{
	char *dst;

	/* nbytes check because some systems (older freebsd's) have a buggy
	 * memchr()
	 */
	if (nbytes && (dst = memchr(buf, '\0', nbytes))) {
		char *end = buf + nbytes;
		char *p, *q;

		for (p = dst; p < end; p = q) {
			/* skip a block of nulls */
			while (++p < end && *p == '\0')
				;
			/* find end of non-null block */
			if (!(q = memchr(p, '\0', end - p)))
				q = end;
			memmove(dst, p, q - p);
			dst += q - p;
		}
		*dst = '\0';
		return dst - buf;
	}
	return nbytes;
}

/* Copy at most dsize-1 bytes from src to dst, ensuring dst is null terminated.
 * Returns dst.
 */
char *
str_zcpy(dst, src, dsize)
	char *dst;
	const char *src;
	int dsize;
{
	if (dsize > 0) {
		int len = strlen(src);

		if (len >= dsize)
			len = dsize - 1;
		memcpy(dst, src, len);
		dst[len] = '\0';
	}
	return dst;
}

/* Like read(2), but if read fails due to non-blocking flag, resets flag
 * and restarts read.
 */
int
blocking_read(fd, buf, nbytes)
	int fd;
	char *buf;
	int nbytes;
{
	int ret;
	int tried_reset = 0;

	while ((ret = read(fd, buf, nbytes)) < 0) {
		if (!tried_reset && (errno == EAGAIN
#ifdef EWOULDBLOCK
				     || errno == EWOULDBLOCK
#endif /* EWOULDBLOCK */
				    ))
		{
			int oerrno = errno;
			if (reset_nonblock(fd) > 0) {
				tried_reset = 1;
				continue;
			}
			errno = oerrno;
		}
		break;
	}
	return ret;
}

/* Reset the non-blocking flag on the specified file descriptor.
 * Returns -1 if there was an error, 0 if non-blocking wasn't set,
 * 1 if it was.
 */
int
reset_nonblock(fd)
	int fd;
{
	int flags;
	int blocking_flags;

	if ((flags = fcntl(fd, F_GETFL, 0)) < 0)
		return -1;
	/* With luck, the C compiler will reduce this to a constant */
	blocking_flags = 0;
#ifdef O_NONBLOCK
	blocking_flags |= O_NONBLOCK;
#endif /* O_NONBLOCK */
#ifdef O_NDELAY
	blocking_flags |= O_NDELAY;
#else /* O_NDELAY */
# ifndef O_NONBLOCK
	blocking_flags |= FNDELAY; /* hope this exists... */
# endif /* O_NONBLOCK */
#endif /* O_NDELAY */
	if (!(flags & blocking_flags))
		return 0;
	flags &= ~blocking_flags;
	if (fcntl(fd, F_SETFL, flags) < 0)
		return -1;
	return 1;
}


#ifdef HAVE_SYS_PARAM_H
# include <sys/param.h>
#endif /* HAVE_SYS_PARAM_H */
#ifndef MAXPATHLEN
# define MAXPATHLEN PATH
#endif /* MAXPATHLEN */

#ifdef HPUX_GETWD_BUG
# include "ksh_dir.h"

/*
 * Work around bug in hpux 10.x C library - getwd/getcwd dump core
 * if current directory is not readable.  Done in macro 'cause code
 * is needed in GETWD and GETCWD cases.
 */
# define HPUX_GETWD_BUG_CODE \
	{ \
	    DIR *d = ksh_opendir("."); \
	    if (!d) \
		return (char *) 0; \
	    closedir(d); \
	}
#else /* HPUX_GETWD_BUG */
# define HPUX_GETWD_BUG_CODE
#endif /* HPUX_GETWD_BUG */

/* Like getcwd(), except bsize is ignored if buf is 0 (MAXPATHLEN is used) */
char *
ksh_get_wd(buf, bsize)
	char *buf;
	int bsize;
{
#ifdef HAVE_GETCWD
	char *b;
	char *ret;

	/* Before memory allocated */
	HPUX_GETWD_BUG_CODE

	/* Assume getcwd() available */
	if (!buf) {
		bsize = MAXPATHLEN;
		b = alloc(MAXPATHLEN + 1, ATEMP);
	} else
		b = buf;

	ret = getcwd(b, bsize);

	if (!buf) {
		if (ret)
			ret = aresize(b, strlen(b) + 1, ATEMP);
		else
			afree(b, ATEMP);
	}

	return ret;
#else /* HAVE_GETCWD */
	extern char *getwd ARGS((char *));
	char *b;
	int len;

	/* Before memory allocated */
	HPUX_GETWD_BUG_CODE

	if (buf && bsize > MAXPATHLEN)
		b = buf;
	else
		b = alloc(MAXPATHLEN + 1, ATEMP);
	if (!getwd(b)) {
		errno = EACCES;
		if (b != buf)
			afree(b, ATEMP);
		return (char *) 0;
	}
	len = strlen(b) + 1;
	if (!buf)
		b = aresize(b, len, ATEMP);
	else if (buf != b) {
		if (len > bsize) {
			errno = ERANGE;
			return (char *) 0;
		}
		memcpy(buf, b, len);
		afree(b, ATEMP);
		b = buf;
	}

	return b;
#endif /* HAVE_GETCWD */
}