diff options
Diffstat (limited to 'matcher.c')
| -rw-r--r-- | matcher.c | 267 |
1 files changed, 267 insertions, 0 deletions
diff --git a/matcher.c b/matcher.c new file mode 100644 index 0000000..1a4a57d --- /dev/null +++ b/matcher.c @@ -0,0 +1,267 @@ +/* + * Copyright (C) 2013 Jo-Philipp Wich <jow@openwrt.org> + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +#include "matcher.h" + +static struct json_object * +jp_match_next(struct jp_opcode *ptr, + struct json_object *root, struct json_object *cur); + +static bool +jp_json_to_op(struct json_object *obj, struct jp_opcode *op) +{ + switch (json_object_get_type(obj)) + { + case json_type_boolean: + op->type = T_BOOL; + op->num = json_object_get_boolean(obj); + return true; + + case json_type_int: + op->type = T_NUMBER; + op->num = json_object_get_int(obj); + return true; + + case json_type_string: + op->type = T_STRING; + op->str = (char *)json_object_get_string(obj); + return true; + + default: + return false; + } +} + +static bool +jp_resolve(struct json_object *root, struct json_object *cur, + struct jp_opcode *op, struct jp_opcode *res) +{ + struct json_object *val; + + switch (op->type) + { + case T_THIS: + val = jp_match(op, cur); + + if (val) + return jp_json_to_op(val, res); + + return false; + + case T_ROOT: + val = jp_match(op, root); + + if (val) + return jp_json_to_op(val, res); + + return false; + + default: + *res = *op; + return true; + } +} + +static bool +jp_cmp(struct jp_opcode *op, struct json_object *root, struct json_object *cur) +{ + int delta; + struct jp_opcode left, right; + + if (!jp_resolve(root, cur, op->down, &left) || + !jp_resolve(root, cur, op->down->sibling, &right)) + return false; + + if (left.type != right.type) + return false; + + switch (left.type) + { + case T_BOOL: + case T_NUMBER: + delta = left.num - right.num; + break; + + case T_STRING: + delta = strcmp(left.str, right.str); + break; + + default: + return false; + } + + switch (op->type) + { + case T_EQ: + return (delta == 0); + + case T_LT: + return (delta < 0); + + case T_LE: + return (delta <= 0); + + case T_GT: + return (delta > 0); + + case T_GE: + return (delta >= 0); + + case T_NE: + return (delta != 0); + + default: + return false; + } +} + +static bool +jp_expr(struct jp_opcode *op, struct json_object *root, struct json_object *cur) +{ + struct jp_opcode *sop; + + switch (op->type) + { + case T_WILDCARD: + return true; + + case T_EQ: + case T_NE: + case T_LT: + case T_LE: + case T_GT: + case T_GE: + return jp_cmp(op, root, cur); + + case T_ROOT: + return !!jp_match(op, root); + + case T_THIS: + return !!jp_match(op, cur); + + case T_NOT: + return !jp_expr(op->down, root, cur); + + case T_AND: + for (sop = op->down; sop; sop = sop->sibling) + if (!jp_expr(sop, root, cur)) + return false; + return true; + + case T_OR: + for (sop = op->down; sop; sop = sop->sibling) + if (jp_expr(sop, root, cur)) + return true; + return false; + + default: + return false; + } +} + +static struct json_object * +jp_match_expr(struct jp_opcode *ptr, + struct json_object *root, struct json_object *cur) +{ + int idx, len; + struct json_object *tmp, *res = NULL; + + switch (json_object_get_type(cur)) + { + case json_type_object: + ; /* a label can only be part of a statement and a declaration is not a statement */ + json_object_object_foreach(cur, key, val) + { + if (!key) + continue; + + if (jp_expr(ptr, root, val)) + { + tmp = jp_match_next(ptr->sibling, root, val); + + if (tmp && !res) + res = tmp; + } + } + + break; + + case json_type_array: + len = json_object_array_length(cur); + + for (idx = 0; idx < len; idx++) + { + tmp = json_object_array_get_idx(cur, idx); + + if (jp_expr(ptr, root, tmp)) + { + tmp = jp_match_next(ptr->sibling, root, tmp); + + if (tmp && !res) + res = tmp; + } + } + + break; + + default: + break; + } + + return res; +} + +static struct json_object * +jp_match_next(struct jp_opcode *ptr, + struct json_object *root, struct json_object *cur) +{ + struct json_object *next; + + if (!ptr) + return cur; + + switch (ptr->type) + { + case T_STRING: + case T_LABEL: + if (json_object_object_get_ex(cur, ptr->str, &next)) + return jp_match_next(ptr->sibling, root, next); + + break; + + case T_NUMBER: + next = json_object_array_get_idx(cur, ptr->num); + + if (next) + return jp_match_next(ptr->sibling, root, next); + + break; + + default: + return jp_match_expr(ptr, root, cur); + } + + return NULL; +} + +struct json_object * +jp_match(struct jp_opcode *path, json_object *jsobj) +{ + if (path->type == T_LABEL) + path = path->down; + + return jp_match_next(path->down, jsobj, jsobj); +} |