Imported Upstream version 93u+upstream

1 files changed, 190 insertions, 0 deletions

diff --git a/src/lib/libast/string/tok.c b/src/lib/libast/string/tok.c
new file mode 100644
index 0000000..c781fb7
--- /dev/null
+++ b/src/lib/libast/string/tok.c
@@ -0,0 +1,190 @@
+/***********************************************************************
+*                                                                      *
+*               This software is part of the ast package               *
+*          Copyright (c) 1985-2011 AT&T Intellectual Property          *
+*                      and is licensed under the                       *
+*                 Eclipse Public License, Version 1.0                  *
+*                    by AT&T Intellectual Property                     *
+*                                                                      *
+*                A copy of the License is available at                 *
+*          http://www.eclipse.org/org/documents/epl-v10.html           *
+*         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *
+*                                                                      *
+*              Information and Software Systems Research               *
+*                            AT&T Research                             *
+*                           Florham Park NJ                            *
+*                                                                      *
+*                 Glenn Fowler <gsf@research.att.com>                  *
+*                  David Korn <dgk@research.att.com>                   *
+*                   Phong Vo <kpv@research.att.com>                    *
+*                                                                      *
+***********************************************************************/
+#pragma prototyped
+/*
+ * Glenn Fowler
+ * AT&T Research
+ *
+ * token stream routines
+ */
+
+#include <ast.h>
+#include <tok.h>
+
+#define FLG_RESTORE	01		/* restore string on close	*/
+#define FLG_NEWLINE	02		/* return newline token next	*/
+
+typedef struct Tok_s			/* token stream state		*/
+{
+	union
+	{
+	char*		end;		/* end ('\0') of last token	*/
+	struct Tok_s*	nxt;		/* next in free list		*/
+	}		ptr;
+	char		chr;		/* replace *end with this	*/
+	char		flg;		/* FLG_*			*/
+} Tok_t;
+
+static Tok_t*		freelist;
+
+/*
+ * open a new token stream on s
+ * if f==0 then string is not restored
+ */
+
+char*
+tokopen(register char* s, int f)
+{
+	register Tok_t*	p;
+
+	if (p = freelist)
+		freelist = freelist->ptr.nxt;
+	else if (!(p = newof(0, Tok_t, 1, 0)))
+		return 0;
+	p->chr = *(p->ptr.end = s);
+	p->flg = f ? FLG_RESTORE : 0;
+	return (char*)p;
+}
+
+/*
+ * close a token stream
+ * restore the string to its original state
+ */
+
+void
+tokclose(char* u)
+{
+	register Tok_t*	p = (Tok_t*)u;
+
+	if (p->flg == FLG_RESTORE && *p->ptr.end != p->chr)
+		*p->ptr.end = p->chr;
+	p->ptr.nxt = freelist;
+	freelist = p;
+}
+
+/*
+ * return next space separated token
+ * "\n" is returned as a token
+ * 0 returned when no tokens remain
+ * "..." and '...' quotes are honored with \ escapes
+ */
+
+char*
+tokread(char* u)
+{
+	register Tok_t*	p = (Tok_t*)u;
+	register char*	s;
+	register char*	r;
+	register int	q;
+	register int	c;
+
+	/*
+	 * restore string on each call
+	 */
+
+	if (!p->chr)
+		return 0;
+	s = p->ptr.end;
+	switch (p->flg)
+	{
+	case FLG_NEWLINE:
+		p->flg = 0;
+		return "\n";
+	case FLG_RESTORE:
+		if (*s != p->chr)
+			*s = p->chr;
+		break;
+	default:
+		if (!*s)
+			s++;
+		break;
+	}
+
+	/*
+	 * skip leading space
+	 */
+
+	while (*s == ' ' || *s == '\t')
+		s++;
+	if (!*s)
+	{
+		p->ptr.end = s;
+		p->chr = 0;
+		return 0;
+	}
+
+	/*
+	 * find the end of this token
+	 */
+
+	r = s;
+	q = 0;
+	for (;;)
+		switch (c = *r++)
+		{
+		case '\n':
+			if (!q)
+			{
+				if (s == (r - 1))
+				{
+					if (!p->flg)
+					{
+						p->ptr.end = r;
+						return "\n";
+					}
+					r++;
+				}
+				else if (!p->flg)
+					p->flg = FLG_NEWLINE;
+			}
+			/*FALLTHROUGH*/
+		case ' ':
+		case '\t':
+			if (q)
+				break;
+			/*FALLTHROUGH*/
+		case 0:
+			if (s == --r)
+			{
+				p->ptr.end = r;
+				p->chr = 0;
+			}
+			else
+			{
+				p->chr = *(p->ptr.end = r);
+				if (*r)
+					*r = 0;
+			}
+			return s;
+		case '\\':
+			if (*r)
+				r++;
+			break;
+		case '"':
+		case '\'':
+			if (c == q)
+				q = 0;
+			else if (!q)
+				q = c;
+			break;
+		}
+}