source: vendor/current/lib/util/strv.c

/*
 * 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 (entry == NULL) {
                if (strv_valid_entry(strv, strv, &len, &entry_len)) {
                        return strv;
                }
                return NULL;
        }

        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);
}