lib: Add "strv" string handling routines

This is a little set of routines designed after the glibc argz
routines. It is supposed to eventually replace our inefficient string_list
routines. A talloc blob is an array of strings separated by the \0
character. See argz(3) on a Linux system for the ideas where this came
from. Based on talloc strv is simpler because talloc knows about the
size of the blob, so we don't have to explicitly maintain it.

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>

3 files changed, 178 insertions, 0 deletions

diff --git a/lib/util/strv.c b/lib/util/strv.c
new file mode 100644
index 0000000000..2acd145add
--- /dev/null
+++ b/lib/util/strv.c
@@ -0,0 +1,141 @@
+/*
+ * String Vector functions modeled after glibc argv_* functions
+ *
+ * Copyright Volker Lendecke <vl@samba.org> 2014
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "replace.h"
+#include "strv.h"
+#include "talloc.h"
+#include <string.h>
+
+static int _strv_append(TALLOC_CTX *mem_ctx, char **dst, const char *src,
+			size_t srclen)
+{
+	size_t dstlen = talloc_array_length(*dst);
+	size_t newlen = dstlen + srclen;
+	char *new_dst;
+
+	if ((newlen < srclen) || (newlen < dstlen)) {
+		return ERANGE;
+	}
+
+	new_dst = talloc_realloc(mem_ctx, *dst, char, newlen);
+	if (new_dst == NULL) {
+		return ENOMEM;
+	}
+	memcpy(&new_dst[dstlen], src, srclen);
+
+	*dst = new_dst;
+	return 0;
+}
+
+int strv_add(TALLOC_CTX *mem_ctx, char **strv, const char *string)
+{
+	return _strv_append(mem_ctx, strv, string, strlen(string)+1);
+}
+
+int strv_append(TALLOC_CTX *mem_ctx, char **strv, const char *src)
+{
+	return _strv_append(mem_ctx, strv, src, talloc_array_length(src));
+}
+
+static bool strv_valid_entry(const char *strv, const char *entry,
+			     size_t *strv_len, size_t *entry_len)
+{
+	size_t len;
+
+	len = talloc_array_length(strv);
+	if (len == 0) {
+		return false;
+	}
+	if (strv[len-1] != '\0') {
+		return false;
+	}
+
+	if (entry < strv) {
+		return false;
+	}
+	if (entry >= (strv+len)) {
+		return false;
+	}
+
+	*strv_len = len;
+	*entry_len = strlen(entry);
+
+	return true;
+}
+
+char *strv_next(char *strv, const char *entry)
+{
+	size_t len, entry_len;
+	char *result;
+
+	if (!strv_valid_entry(strv, entry, &len, &entry_len)) {
+		return NULL;
+	}
+	result = &strv[entry - strv]; /* avoid const problems with this stmt */
+	result += entry_len + 1;
+
+	if (result >= (strv + len)) {
+		return NULL;
+	}
+	return result;
+}
+
+size_t strv_count(char *strv)
+{
+	char *entry;
+	size_t count = 0;
+
+	for (entry = strv; entry != NULL; entry = strv_next(strv, entry)) {
+		count += 1;
+	}
+
+	return count;
+}
+
+char *strv_find(char *strv, const char *entry)
+{
+	char *e = NULL;
+
+	while ((e = strv_next(strv, e)) != NULL) {
+		if (strcmp(e, entry) == 0) {
+			return e;
+		}
+	}
+
+	return NULL;
+}
+
+void strv_delete(char **strv, char *entry)
+{
+	size_t len, entry_len;
+
+	if (entry == NULL) {
+		return;
+	}
+
+	if (!strv_valid_entry(*strv, entry, &len, &entry_len)) {
+		return;
+	}
+	entry_len += 1;
+
+	memmove(entry, entry+entry_len,
+		len - entry_len - (entry - *strv));
+
+	*strv = talloc_realloc(NULL, *strv, char, len - entry_len);
+}
diff --git a/lib/util/strv.h b/lib/util/strv.h
new file mode 100644
index 0000000000..843ce5c8ca
--- /dev/null
+++ b/lib/util/strv.h
@@ -0,0 +1,32 @@
+/*
+ * String Vector functions modeled after glibc argv_* functions
+ *
+ * Copyright Volker Lendecke <vl@samba.org> 2014
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _STRV_H_
+#define _STRV_H_
+
+#include "talloc.h"
+
+int strv_add(TALLOC_CTX *mem_ctx, char **strv, const char *string);
+int strv_append(TALLOC_CTX *mem_ctx, char **strv, const char *src);
+char *strv_next(char *strv, const char *entry);
+char *strv_find(char *strv, const char *entry);
+size_t strv_count(char *strv);
+void strv_delete(char **strv, char *entry);
+
+#endif
diff --git a/lib/util/wscript_build b/lib/util/wscript_build
index cd23231f3c..83d0bf1d15 100755
--- a/lib/util/wscript_build
+++ b/lib/util/wscript_build
@@ -15,6 +15,11 @@ bld.SAMBA_SUBSYSTEM('tiniparser',
                     deps='tini',
                     local_include=False)
 
+bld.SAMBA_SUBSYSTEM('strv',
+                    source='strv.c',
+                    deps='talloc',
+                    local_include=False)
+
 bld.SAMBA_SUBSYSTEM('close-low-fd',
                     source='close_low_fd.c',
                     deps='replace',