1 #include "adventure.h"
2 
3 #include <ctype.h>
4 #include <string.h>
5 
6 struct param params[MAX_PARAMS];
7 
8 static const char *
9 skip_spaces(const char *src)
10 {
11 	while (isspace(*src))
12 		src++;
13 	return src;
14 }
15 
16 static const char *
17 match_spaces(const char *src)
18 {
19 	return *src == '\0' || isspace(*src) ? skip_spaces(src) : NULL;
20 }
21 
22 static const char *
23 match_terminal(const char *src, char terminal)
24 {
25 	return terminal == ' '
26 		? match_spaces(src)
27 		: tolower(*src) == tolower(terminal)
28 			? src + 1
29 			: NULL;
30 }
31 
32 static const char *
33 match_tag(const char *src, const char *tag)
34 {
35 	while (src != NULL && *tag != '\0')
36 		src = match_terminal(src, *tag++);
37 	return src;
38 }
39 
40 static int
41 compare_with_param(const char *tag, enum distance dist, struct param *par)
42 {
43 	int diff = strlen(tag) - strlen(par->tag);
44 	if (diff == 0)
45 		diff = par->distance - dist;
46 	if (diff == 0)
47 		par->count++;
48 	return diff;
49 }
50 
51 static const char *
52 match_param(const char *src, struct param *par, int loose)
53 {
54 	struct object *obj;
55 	const char *rest_of_src = loose ? src + strlen(src) : NULL;
56 
57 	par->tag = src;
58 	par->distance = *src == '\0' ? dist_no_obj_specified : dist_unknown_obj;
59 
60 	foreach_obj (obj) {
61 		const char **tag;
62 		enum distance dist = distance_to(obj);
63 		for (tag = obj->tags; *tag != NULL; ++tag) {
64 			const char *behind_match = match_tag(src, *tag);
65 			if (behind_match != NULL &&
66 					compare_with_param(*tag, dist, par) > 0 &&
67 					(!loose || *skip_spaces(behind_match) == '\0')) {
68 				par->tag = *tag;
69 				par->object = obj;
70 				par->distance = dist;
71 				par->count = 1;
72 				rest_of_src = behind_match;
73 			}
74 		}
75 	}
76 
77 	return rest_of_src;
78 }
79 
80 int
81 match_command(const char *src, const char *pattern)
82 {
83 	struct param *par;
84 
85 	/* clean params */
86 	for (par = params; par < params + MAX_PARAMS; ++par) {
87 		par->object = NULL;
88 		par->distance = dist_no_obj_specified;
89 		par->count = 0;
90 	}
91 
92 	/* actual parsing */
93 	for (src = skip_spaces(src); src != NULL && *pattern != '\0'; ++pattern) {
94 		src = isupper(*pattern)
95 			? match_param(src, param_by_letter(*pattern),
96 						pattern[1] == '?')
97 			: *pattern == '?'
98 				? src
99 				: match_terminal(src, *pattern);
100 	}
101 
102 	return src != NULL && *skip_spaces(src) == '\0';
103 }