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
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
|
/*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* Jordan K. Hubbard
* 29 August 1998
*
* $Id: interp_parse.c,v 1.2 1998/09/03 06:14:41 jkh Exp $
*
* The meat of the simple parser.
*/
#include <stand.h>
#include <string.h>
/* Forward decls */
extern char *backslash(char *str);
static void init(int *argcp, char ***argvp);
static void clean(void);
static int insert(int *argcp, char *buf);
static char *variable_lookup(char *name);
#define PARSE_BUFSIZE 1024 /* maximum size of one element */
#define MAXARGS 20 /* maximum number of elements */
static char *args[MAXARGS];
/*
* parse: accept a string of input and "parse" it for backslash
* substitutions and environment variable expansions (${var}),
* returning an argc/argv style vector of whitespace separated
* arguments. Returns 0 on success, 1 on failure (ok, ok, so I
* wimped-out on the error codes! :).
*
* Note that the argv array returned must be freed by the caller, but
* we own the space allocated for arguments and will free that on next
* invocation. This allows argv consumers to modify the array if
* required.
*
* NB: environment variables that expand to more than one whitespace
* separated token will be returned as a single argv[] element, not
* split in turn. Expanded text is also immune to further backslash
* elimination or expansion since this is a one-pass, non-recursive
* parser. You didn't specify more than this so if you want more, ask
* me. - jkh
*/
#define PARSE_FAIL(expr) \
if (expr) { \
printf("fail at line %d\n", __LINE__); \
clean(); \
free(copy); \
free(buf); \
return 1; \
}
/* Accept the usual delimiters for a variable, returning counterpart */
static char
isdelim(char ch)
{
if (ch == '{')
return '}';
else if (ch == '(')
return ')';
return '\0';
}
static int
isquote(char ch)
{
return (ch == '\'' || ch == '"');
}
int
parse(int *argc, char ***argv, char *str)
{
int ac;
char *val, *p, *q, *copy = NULL;
int i = 0;
char token, tmp, quote, *buf;
enum { STR, VAR, WHITE } state;
ac = *argc = 0;
quote = 0;
if (!str || (p = copy = backslash(str)) == NULL)
return 1;
/* Initialize vector and state */
clean();
state = STR;
buf = (char *)malloc(PARSE_BUFSIZE);
token = 0;
/* And awaaaaaaaaay we go! */
while (*p) {
switch (state) {
case STR:
if (isquote(*p)) {
quote = quote ? 0 : *p;
++p;
}
else if (isspace(*p) && !quote) {
state = WHITE;
if (i) {
buf[i] = '\0';
PARSE_FAIL(insert(&ac, buf));
i = 0;
}
++p;
} else if (*p == '$') {
token = isdelim(*(p + 1));
if (token)
p += 2;
else
++p;
state = VAR;
} else {
PARSE_FAIL(i == (PARSE_BUFSIZE - 1));
buf[i++] = *p++;
}
break;
case WHITE:
if (isspace(*p))
++p;
else
state = STR;
break;
case VAR:
if (token) {
PARSE_FAIL((q = index(p, token)) == NULL);
} else {
q = p;
while (*q && !isspace(*q))
++q;
}
tmp = *q;
*q = '\0';
if ((val = variable_lookup(p)) != NULL) {
int len = strlen(val);
strncpy(buf + i, val, PARSE_BUFSIZE - (i + 1));
i += min(len, PARSE_BUFSIZE - 1);
}
*q = tmp; /* restore value */
p = q + (token ? 1 : 0);
state = STR;
break;
}
}
/* If at end of token, add it */
if (i && state == STR) {
buf[i] = '\0';
PARSE_FAIL(insert(&ac, buf));
}
args[ac] = NULL;
*argc = ac;
*argv = (char **)malloc((sizeof(char *) * ac + 1));
bcopy(args, *argv, sizeof(char *) * ac + 1);
free(copy);
return 0;
}
#define MAXARGS 20
/* Clean vector space */
static void
clean(void)
{
int i;
for (i = 0; i < MAXARGS; i++) {
if (args[i] != NULL) {
free(args[i]);
args[i] = NULL;
}
}
}
static int
insert(int *argcp, char *buf)
{
if (*argcp >= MAXARGS)
return 1;
args[(*argcp)++] = strdup(buf);
return 0;
}
static char *
variable_lookup(char *name)
{
/* XXX search "special variable" space first? */
return (char *)getenv(name);
}
|
