diff options
Diffstat (limited to 'common/env_attr.c')
| -rw-r--r-- | common/env_attr.c | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/common/env_attr.c b/common/env_attr.c new file mode 100644 index 0000000..7d330a5 --- /dev/null +++ b/common/env_attr.c @@ -0,0 +1,222 @@ +/* + * (C) Copyright 2012 + * Joe Hershberger, National Instruments, joe.hershberger@ni.com + * + * See file CREDITS for list of people who contributed to this + * project. + * + * 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 2 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, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#include <common.h> +#include <env_attr.h> +#include <errno.h> +#include <linux/string.h> +#include <malloc.h> + +/* + * Iterate through the whole list calling the callback for each found element. + * "attr_list" takes the form: + * attributes = [^,:\s]* + * entry = name[:attributes] + * list = entry[,list] + */ +int env_attr_walk(const char *attr_list, + int (*callback)(const char *name, const char *attributes)) +{ + const char *entry, *entry_end; + char *name, *attributes; + + if (!attr_list) + /* list not found */ + return 1; + + entry = attr_list; + do { + char *entry_cpy = NULL; + + entry_end = strchr(entry, ENV_ATTR_LIST_DELIM); + /* check if this is the last entry in the list */ + if (entry_end == NULL) { + int entry_len = strlen(entry); + + if (entry_len) { + /* + * allocate memory to copy the entry into since + * we will need to inject '\0' chars and squash + * white-space before calling the callback + */ + entry_cpy = malloc(entry_len + 1); + if (entry_cpy) + /* copy the rest of the list */ + strcpy(entry_cpy, entry); + else + return -ENOMEM; + } + } else { + int entry_len = entry_end - entry; + + if (entry_len) { + /* + * allocate memory to copy the entry into since + * we will need to inject '\0' chars and squash + * white-space before calling the callback + */ + entry_cpy = malloc(entry_len + 1); + if (entry_cpy) { + /* copy just this entry and null term */ + strncpy(entry_cpy, entry, entry_len); + entry_cpy[entry_len] = '\0'; + } else + return -ENOMEM; + } + } + + /* check if there is anything to process (e.g. not ",,,") */ + if (entry_cpy != NULL) { + attributes = strchr(entry_cpy, ENV_ATTR_SEP); + /* check if there is a ':' */ + if (attributes != NULL) { + /* replace the ':' with '\0' to term name */ + *attributes++ = '\0'; + /* remove white-space from attributes */ + attributes = strim(attributes); + } + /* remove white-space from name */ + name = strim(entry_cpy); + + /* only call the callback if there is a name */ + if (strlen(name) != 0) { + int retval = 0; + + retval = callback(name, attributes); + if (retval) { + free(entry_cpy); + return retval; + } + } + } + + free(entry_cpy); + entry = entry_end + 1; + } while (entry_end != NULL); + + return 0; +} + +/* + * Search for the last matching string in another string with the option to + * start looking at a certain point (i.e. ignore anything beyond that point). + */ +static char *reverse_strstr(const char *searched, const char *search_for, + const char *searched_start) +{ + char *result = NULL; + + if (*search_for == '\0') + return (char *)searched; + + for (;;) { + char *match = strstr(searched, search_for); + + /* + * Stop looking if no new match is found or looking past the + * searched_start pointer + */ + if (match == NULL || (searched_start != NULL && + match + strlen(search_for) > searched_start)) + break; + + result = match; + searched = match + 1; + } + + return result; +} + +/* + * Retrieve the attributes string associated with a single name in the list + * There is no protection on attributes being too small for the value + */ +int env_attr_lookup(const char *attr_list, const char *name, char *attributes) +{ + const char *entry = NULL; + + if (!attributes) + /* bad parameter */ + return -1; + if (!attr_list) + /* list not found */ + return 1; + + entry = reverse_strstr(attr_list, name, NULL); + while (entry != NULL) { + const char *prevch = entry - 1; + const char *nextch = entry + strlen(name); + + /* Skip spaces */ + while (*prevch == ' ') + prevch--; + while (*nextch == ' ') + nextch++; + + /* check for an exact match */ + if ((entry == attr_list || + *prevch == ENV_ATTR_LIST_DELIM) && + (*nextch == ENV_ATTR_SEP || + *nextch == ENV_ATTR_LIST_DELIM || + *nextch == '\0')) + break; + + entry = reverse_strstr(attr_list, name, entry); + } + if (entry != NULL) { + int len; + + /* skip the name */ + entry += strlen(name); + /* skip spaces */ + while (*entry == ' ') + entry++; + if (*entry != ENV_ATTR_SEP) + len = 0; + else { + const char *delim; + static const char delims[] = { + ENV_ATTR_LIST_DELIM, ' ', '\0'}; + + /* skip the attr sep */ + entry += 1; + /* skip spaces */ + while (*entry == ' ') + entry++; + + delim = strpbrk(entry, delims); + if (delim == NULL) + len = strlen(entry); + else + len = delim - entry; + memcpy(attributes, entry, len); + } + attributes[len] = '\0'; + + /* success */ + return 0; + } + + /* not found in list */ + return 2; +} |