hashtable: preparations to use hexport_r() for "env grep"

The output of "env grep" is unsorted, and printing is done by a
private implementation to parse the hash table.  We have all the
needed code in place in hexport_r() alsready, so let's use this
instead.  Here we prepare the code for this, without any functional
changes yet.

Signed-off-by: Wolfgang Denk <wd@denx.de>

common/cmd_nvedit.c

@@ -1,5 +1,5 @@
 /*
- * (C) Copyright 2000-2010
+ * (C) Copyright 2000-2013
  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
  *
  * (C) Copyright 2001 Sysgo Real-Time Solutions, GmbH <www.elinos.com>
@@ -892,7 +892,9 @@ NXTARG:		;
 	argv++;
 
 	if (sep) {		/* export as text file */
-		len = hexport_r(&env_htab, sep, 0, &addr, size, argc, argv);
+		len = hexport_r(&env_htab, sep,
+				H_MATCH_KEY | H_MATCH_IDENT,
+				&addr, size, argc, argv);
 		if (len < 0) {
 			error("Cannot export environment: errno = %d\n", errno);
 			return 1;
@@ -910,7 +912,9 @@ NXTARG:		;
 	else			/* export as raw binary data */
 		res = addr;
 
-	len = hexport_r(&env_htab, '\0', 0, &res, ENV_SIZE, argc, argv);
+	len = hexport_r(&env_htab, '\0',
+			H_MATCH_KEY | H_MATCH_IDENT,
+			&res, ENV_SIZE, argc, argv);
 	if (len < 0) {
 		error("Cannot export environment: errno = %d\n", errno);
 		return 1;

include/search.h

@@ -22,7 +22,7 @@
 /*
  * Based on code from uClibc-0.9.30.3
  * Extensions for use within U-Boot
- * Copyright (C) 2010 Wolfgang Denk <wd@denx.de>
+ * Copyright (C) 2010-2013 Wolfgang Denk <wd@denx.de>
  */
 
 #ifndef _SEARCH_H
@@ -131,5 +131,11 @@ extern int hwalk_r(struct hsearch_data *__htab, int (*callback)(ENTRY *));
 #define H_FORCE		(1 << 1) /* overwrite read-only/write-once variables */
 #define H_INTERACTIVE	(1 << 2) /* indicate that an import is user directed */
 #define H_HIDE_DOT	(1 << 3) /* don't print env vars that begin with '.' */
+#define H_MATCH_KEY	(1 << 4) /* search/grep key  = variable names	     */
+#define H_MATCH_DATA	(1 << 5) /* search/grep data = variable values	     */
+#define H_MATCH_BOTH	(H_MATCH_KEY | H_MATCH_DATA) /* search/grep both     */
+#define H_MATCH_IDENT	(1 << 6) /* search for indentical strings	     */
+#define H_MATCH_SUBSTR  (1 << 7) /* search for substring matches	     */
+#define H_MATCH_METHOD	(H_MATCH_IDENT | H_MATCH_SUBSTR)
 
 #endif /* search.h */

lib/hashtable.c

@@ -2,7 +2,7 @@
  * This implementation is based on code from uClibc-0.9.30.3 but was
  * modified and extended for use within U-Boot.
  *
- * Copyright (C) 2010 Wolfgang Denk <wd@denx.de>
+ * Copyright (C) 2010-2013 Wolfgang Denk <wd@denx.de>
  *
  * Original license header:
  *
@@ -563,6 +563,28 @@ static int cmpkey(const void *p1, const void *p2)
 	return (strcmp(e1->key, e2->key));
 }
 
+static int match_strings(ENTRY *ep, int flag,
+		 int argc, char * const argv[])
+{
+	int arg;
+
+	for (arg = 0; arg < argc; ++arg) {
+		if (flag & H_MATCH_KEY) {
+			switch (flag & H_MATCH_METHOD) {
+			case H_MATCH_IDENT:
+				if (strcmp(argv[arg], ep->key) == 0)
+					return 1;
+				break;
+			default:
+				printf("## ERROR: unsupported match method: 0x%02x\n",
+					flag & H_MATCH_METHOD);
+				break;
+			}
+		}
+	}
+	return 0;
+}
+
 ssize_t hexport_r(struct hsearch_data *htab, const char sep, int flag,
 		 char **resp, size_t size,
 		 int argc, char * const argv[])
@@ -589,14 +611,8 @@ ssize_t hexport_r(struct hsearch_data *htab, const char sep, int flag,
 
 		if (htab->table[i].used > 0) {
 			ENTRY *ep = &htab->table[i].entry;
-			int arg, found = 0;
+			int found = match_strings(ep, flag, argc, argv);
 
-			for (arg = 0; arg < argc; ++arg) {
-				if (strcmp(argv[arg], ep->key) == 0) {
-					found = 1;
-					break;
-				}
-			}
 			if ((argc > 0) && (found == 0))
 				continue;