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07516736 AK |
1 | /* Simple expression parser */ |
2 | %{ | |
3 | #include "util.h" | |
4 | #include "util/debug.h" | |
5 | #define IN_EXPR_Y 1 | |
6 | #include "expr.h" | |
7 | #include <string.h> | |
8 | ||
9 | #define MAXIDLEN 256 | |
10 | %} | |
11 | ||
12 | %pure-parser | |
13 | %parse-param { double *final_val } | |
14 | %parse-param { struct parse_ctx *ctx } | |
15 | %parse-param { const char **pp } | |
16 | %lex-param { const char **pp } | |
17 | ||
18 | %union { | |
19 | double num; | |
20 | char id[MAXIDLEN+1]; | |
21 | } | |
22 | ||
23 | %token <num> NUMBER | |
24 | %token <id> ID | |
25 | %left '|' | |
26 | %left '^' | |
27 | %left '&' | |
28 | %left '-' '+' | |
29 | %left '*' '/' '%' | |
30 | %left NEG NOT | |
31 | %type <num> expr | |
32 | ||
33 | %{ | |
34 | static int expr__lex(YYSTYPE *res, const char **pp); | |
35 | ||
36 | static void expr__error(double *final_val __maybe_unused, | |
37 | struct parse_ctx *ctx __maybe_unused, | |
38 | const char **pp __maybe_unused, | |
39 | const char *s) | |
40 | { | |
41 | pr_debug("%s\n", s); | |
42 | } | |
43 | ||
44 | static int lookup_id(struct parse_ctx *ctx, char *id, double *val) | |
45 | { | |
46 | int i; | |
47 | ||
48 | for (i = 0; i < ctx->num_ids; i++) { | |
49 | if (!strcasecmp(ctx->ids[i].name, id)) { | |
50 | *val = ctx->ids[i].val; | |
51 | return 0; | |
52 | } | |
53 | } | |
54 | return -1; | |
55 | } | |
56 | ||
57 | %} | |
58 | %% | |
59 | ||
60 | all_expr: expr { *final_val = $1; } | |
61 | ; | |
62 | ||
63 | expr: NUMBER | |
64 | | ID { if (lookup_id(ctx, $1, &$$) < 0) { | |
65 | pr_debug("%s not found", $1); | |
66 | YYABORT; | |
67 | } | |
68 | } | |
69 | | expr '+' expr { $$ = $1 + $3; } | |
70 | | expr '-' expr { $$ = $1 - $3; } | |
71 | | expr '*' expr { $$ = $1 * $3; } | |
72 | | expr '/' expr { if ($3 == 0) YYABORT; $$ = $1 / $3; } | |
73 | | expr '%' expr { if ((long)$3 == 0) YYABORT; $$ = (long)$1 % (long)$3; } | |
74 | | '-' expr %prec NEG { $$ = -$2; } | |
75 | | '(' expr ')' { $$ = $2; } | |
76 | ; | |
77 | ||
78 | %% | |
79 | ||
80 | static int expr__symbol(YYSTYPE *res, const char *p, const char **pp) | |
81 | { | |
82 | char *dst = res->id; | |
83 | const char *s = p; | |
84 | ||
85 | while (isalnum(*p) || *p == '_' || *p == '.') { | |
86 | if (p - s >= MAXIDLEN) | |
87 | return -1; | |
88 | *dst++ = *p++; | |
89 | } | |
90 | *dst = 0; | |
91 | *pp = p; | |
92 | return ID; | |
93 | } | |
94 | ||
95 | static int expr__lex(YYSTYPE *res, const char **pp) | |
96 | { | |
97 | int tok; | |
98 | const char *s; | |
99 | const char *p = *pp; | |
100 | ||
101 | while (isspace(*p)) | |
102 | p++; | |
103 | s = p; | |
104 | switch (*p++) { | |
105 | case 'a' ... 'z': | |
106 | case 'A' ... 'Z': | |
107 | return expr__symbol(res, p - 1, pp); | |
108 | case '0' ... '9': case '.': | |
109 | res->num = strtod(s, (char **)&p); | |
110 | tok = NUMBER; | |
111 | break; | |
112 | default: | |
113 | tok = *s; | |
114 | break; | |
115 | } | |
116 | *pp = p; | |
117 | return tok; | |
118 | } | |
119 | ||
120 | /* Caller must make sure id is allocated */ | |
121 | void expr__add_id(struct parse_ctx *ctx, const char *name, double val) | |
122 | { | |
123 | int idx; | |
124 | assert(ctx->num_ids < MAX_PARSE_ID); | |
125 | idx = ctx->num_ids++; | |
126 | ctx->ids[idx].name = name; | |
127 | ctx->ids[idx].val = val; | |
128 | } | |
129 | ||
130 | void expr__ctx_init(struct parse_ctx *ctx) | |
131 | { | |
132 | ctx->num_ids = 0; | |
133 | } | |
134 | ||
135 | int expr__find_other(const char *p, const char *one, const char ***other, | |
136 | int *num_otherp) | |
137 | { | |
138 | const char *orig = p; | |
139 | int err = -1; | |
140 | int num_other; | |
141 | ||
142 | *other = malloc((EXPR_MAX_OTHER + 1) * sizeof(char *)); | |
143 | if (!*other) | |
144 | return -1; | |
145 | ||
146 | num_other = 0; | |
147 | for (;;) { | |
148 | YYSTYPE val; | |
149 | int tok = expr__lex(&val, &p); | |
150 | if (tok == 0) { | |
151 | err = 0; | |
152 | break; | |
153 | } | |
154 | if (tok == ID && strcasecmp(one, val.id)) { | |
155 | if (num_other >= EXPR_MAX_OTHER - 1) { | |
156 | pr_debug("Too many extra events in %s\n", orig); | |
157 | break; | |
158 | } | |
159 | (*other)[num_other] = strdup(val.id); | |
160 | if (!(*other)[num_other]) | |
161 | return -1; | |
162 | num_other++; | |
163 | } | |
164 | } | |
165 | (*other)[num_other] = NULL; | |
166 | *num_otherp = num_other; | |
167 | if (err) { | |
168 | *num_otherp = 0; | |
169 | free(*other); | |
170 | *other = NULL; | |
171 | } | |
172 | return err; | |
173 | } |