Doubled the performance of getenv()/__findenv() by rewriting it to not

use strncmp()..

1 files changed, 24 insertions, 20 deletions

diff --git a/lib/libc/stdlib/getenv.c b/lib/libc/stdlib/getenv.c
index 7407e0b..a6bbd35 100644
--- a/lib/libc/stdlib/getenv.c
+++ b/lib/libc/stdlib/getenv.c
@@ -39,20 +39,7 @@ static char sccsid[] = "@(#)getenv.c	8.1 (Berkeley) 6/4/93";
 #include <stddef.h>
 #include <string.h>
 
-char *__findenv __P((const char *, int *));
-
-/*
- * getenv --
- *	Returns ptr to value associated with name, if any, else NULL.
- */
-char *
-getenv(name)
-	const char *name;
-{
-	int offset;
-
-	return (__findenv(name, &offset));
-}
+inline char *__findenv __P((const char *, int *));
 
 /*
  * __findenv --
@@ -63,25 +50,42 @@ getenv(name)
  *
  *	This routine *should* be a static; don't use it.
  */
-char *
+inline char *
 __findenv(name, offset)
 	register const char *name;
 	int *offset;
 {
 	extern char **environ;
-	register int len;
+	register int len, i;
 	register const char *np;
-	register char **p, *c;
+	register char **p, *cp;
 
 	if (name == NULL || environ == NULL)
 		return (NULL);
 	for (np = name; *np && *np != '='; ++np)
 		continue;
 	len = np - name;
-	for (p = environ; (c = *p) != NULL; ++p)
-		if (strncmp(c, name, len) == 0 && c[len] == '=') {
+	for (p = environ; (cp = *p) != NULL; ++p) {
+		for (np = name, i = len; i && *cp; i--)
+			if (*cp++ != *np++)
+				break;
+		if (i == 0 && *cp++ == '=') {
 			*offset = p - environ;
-			return (c + len + 1);
+			return (cp);
 		}
+	}
 	return (NULL);
 }
+
+/*
+ * getenv --
+ *	Returns ptr to value associated with name, if any, else NULL.
+ */
+char *
+getenv(name)
+	const char *name;
+{
+	int offset;
+
+	return (__findenv(name, &offset));
+}