blob: b93150935cdb1983dabf8b66ff2ee39b3d81307d (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
|
/*
* (C) Copyright 2016 Leo C. <erbl259-lmu@yahoo.de>
*
* SPDX-License-Identifier: GPL-2.0
*/
#include "eval_arg.h"
#include "common.h"
#include <stdlib.h>
#include <ctype.h>
#include <setjmp.h>
#include "print-utils.h"
#include "command.h" /* jump_buf */
static jmp_buf eval_jbuf;
static char ch;
static char *start_p;
static char *bp;
static long expr(void);
static void print_error_pos(void)
{
printf_P(PSTR("Arg: '%s'\n"
" "), start_p);
print_blanks(bp - start_p);
my_puts_P(PSTR("^syntax error!\n"));
}
static void error (void)
{
--bp;
longjmp (eval_jbuf, 1);
}
static void next(void)
{
do
ch = *bp++;
while (isspace(ch));
}
static long number (void)
{
int base = 16;
char *end_p;
long n;
if (ch == '$') { /* FIXME: should be '#' */
next();
base = 10;
}
if (!isdigit(ch) && !(base == 16 && isxdigit(ch)))
error ();
n = strtoul(bp - 1, &end_p, base);
if (end_p == bp - 1)
error();
bp = end_p;
next();
return n;
}
static long factor (void)
{
long f;
if (ch == '(')
{
next();
f = expr();
if (ch == ')')
next();
else
error ();
} else {
char sign = ch;
if (sign == '+' || sign == '-') {
next();
}
f = number();
if (sign == '-')
f = -f;
}
return f;
}
static long term (void)
{
long t = factor();
for (;;)
switch (ch) {
case '*':
next();
t *= factor();
break;
case '/':
next();
t /= factor();
break;
case '%':
next();
t %= factor();
break;
default:
return t;
}
}
static long expr(void)
{
long e = term ();
while (ch == '+' || ch == '-') {
char op = ch;
next();
if (op == '-')
e -= term ();
else
e += term ();
}
return e;
}
long eval_arg(char *arg, char **end_ptr)
{
long val;
start_p = arg;
bp = arg;
next();
if (setjmp (eval_jbuf) != 0) {
if (!end_ptr) {
print_error_pos();
longjmp(cmd_jbuf, 1);
}
val = -1;
} else {
val = expr ();
--bp;
}
if (!end_ptr) {
if (*bp != '\0') {
print_error_pos();
longjmp(cmd_jbuf, 1);
}
} else
*end_ptr = bp;
return val;
}
|
