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fcd2239e L |
1 | /* |
2 | * (C) Copyright 2016 Leo C. <erbl259-lmu@yahoo.de> | |
3 | * | |
4 | * SPDX-License-Identifier: GPL-2.0 | |
5 | */ | |
6 | ||
7 | #include "eval_arg.h" | |
8 | #include "common.h" | |
9 | #include <stdlib.h> | |
10 | #include <ctype.h> | |
11 | #include <setjmp.h> | |
12 | #include "print-utils.h" | |
13 | #include "command.h" /* jump_buf */ | |
14 | ||
15 | static jmp_buf eval_jbuf; | |
16 | static char ch; | |
17 | static char *start_p; | |
18 | static char *bp; | |
19 | ||
20 | ||
21 | static long expr(void); | |
22 | ||
23 | static void print_error_pos(void) | |
24 | { | |
25 | printf_P(PSTR("Arg: '%s'\n" | |
26 | " "), start_p); | |
27 | print_blanks(bp - start_p); | |
28 | my_puts_P(PSTR("^syntax error!\n")); | |
29 | } | |
30 | ||
31 | static void error (void) | |
32 | { | |
33 | --bp; | |
34 | longjmp (eval_jbuf, 1); | |
35 | } | |
36 | ||
37 | static void next(void) | |
38 | { | |
39 | do | |
40 | ch = *bp++; | |
41 | while (ch == ' ' || ch == '\n'); | |
42 | } | |
43 | ||
44 | static long number (void) | |
45 | { | |
46 | int base = 16; | |
47 | char *end_p; | |
48 | long n; | |
49 | ||
50 | if (ch == '$') { /* FIXME: should be '#' */ | |
51 | next(); | |
52 | base = 10; | |
53 | } | |
54 | if (!isdigit(ch) && !(base == 16 && isxdigit(ch))) | |
55 | error (); | |
56 | ||
57 | n = strtoul(bp - 1, &end_p, base); | |
58 | ||
59 | if (end_p == bp - 1) | |
60 | error(); | |
61 | bp = end_p; | |
62 | next(); | |
63 | ||
64 | return n; | |
65 | } | |
66 | ||
67 | static long factor (void) | |
68 | { | |
69 | long f; | |
70 | ||
71 | if (ch == '(') | |
72 | { | |
73 | next(); | |
74 | f = expr(); | |
75 | if (ch == ')') | |
76 | next(); | |
77 | else | |
78 | error (); | |
79 | } | |
80 | else | |
81 | f = number (); | |
82 | ||
83 | return f; | |
84 | } | |
85 | ||
86 | static long term (void) | |
87 | { | |
88 | long t = factor(); | |
89 | ||
90 | for (;;) | |
91 | switch (ch) { | |
92 | case '*': | |
93 | next(); | |
94 | t *= factor(); | |
95 | break; | |
96 | case '/': | |
97 | next(); | |
98 | t /= factor(); | |
99 | break; | |
100 | case '%': | |
101 | next(); | |
102 | t %= factor(); | |
103 | break; | |
104 | default: | |
105 | return t; | |
106 | } | |
107 | } | |
108 | ||
109 | ||
110 | static long expr(void) | |
111 | { | |
112 | long e; | |
113 | ||
114 | if (ch == '+') { | |
115 | next(); | |
116 | e = term (); | |
117 | } else if (ch == '-') { | |
118 | next(); | |
119 | e = - term (); | |
120 | } else | |
121 | e = term (); | |
122 | ||
123 | while (ch == '+' || ch == '-') { | |
124 | char op = ch; | |
125 | next(); | |
126 | if (op == '-') | |
127 | e -= term (); | |
128 | else | |
129 | e += term (); | |
130 | } | |
131 | return e; | |
132 | } | |
133 | ||
134 | long eval_arg(char *arg, char **end_ptr) | |
135 | { | |
136 | long val; | |
137 | ||
138 | start_p = arg; | |
139 | bp = arg; | |
140 | next(); | |
141 | if (setjmp (eval_jbuf) != 0) { | |
142 | if (!end_ptr) { | |
143 | print_error_pos(); | |
144 | longjmp(cmd_jbuf, 1); | |
145 | } | |
146 | val = -1; | |
147 | } else { | |
148 | val = expr (); | |
149 | --bp; | |
150 | } | |
151 | ||
152 | if (!end_ptr) { | |
153 | if (*bp != '\0') { | |
154 | print_error_pos(); | |
155 | longjmp(cmd_jbuf, 1); | |
156 | } | |
157 | } else | |
158 | *end_ptr = bp; | |
159 | ||
160 | return val; | |
161 | } |