1 #include <ctype.h>
2 #include <string.h>
3 
4 #include "adventure.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) ? src + 1 : NULL;
28 }
29 
30 static const char *
31 match_tag(const char *src, const char *tag)
32 {
33 	while (src != NULL && *tag != '\0')
34 		src = match_terminal(src, *tag++);
35 	return src;
36 }
37 
38 static int
39 compare_with_param(const char *tag, enum distance dist, struct param *par)
40 {
41 	int diff = strlen(tag) - strlen(par->tag);
42 	if (diff == 0)
43 		diff = par->distance - dist;
44 	if (diff == 0)
45 		par->count++;
46 	return diff;
47 }
48 
49 static const char *
50 match_param(const char *src, struct param *par, int loose)
51 {
52 	struct object *obj;
53 	const char *rest_of_src = loose ? src + strlen(src) : NULL;
54 
55 	par->tag = src;
56 	par->distance
57 		= *src == '\0' ? dist_no_obj_specified : dist_unknown_obj;
58 
59 	foreach_obj(obj)
60 	{
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
68 					|| *skip_spaces(behind_match)
69 						== '\0')) {
70 				par->tag = *tag;
71 				par->object = obj;
72 				par->distance = dist;
73 				par->count = 1;
74 				rest_of_src = behind_match;
75 			}
76 		}
77 	}
78 
79 	return rest_of_src;
80 }
81 
82 int
83 match_command(const char *src, const char *pattern)
84 {
85 	struct param *par;
86 
87 	/* clean params */
88 	for (par = params; par < params + MAX_PARAMS; ++par) {
89 		par->object = NULL;
90 		par->distance = dist_no_obj_specified;
91 		par->count = 0;
92 	}
93 
94 	/* actual parsing */
95 	for (src = skip_spaces(src); src != NULL && *pattern != '\0';
96 		++pattern) {
97 		src = isupper(*pattern)
98 			? match_param(src, param_by_letter(*pattern),
99 				pattern[1] == '?')
100 			: *pattern == '?' ? src
101 					  : match_terminal(src, *pattern);
102 	}
103 
104 	return src != NULL && *skip_spaces(src) == '\0';
105 }