Repository navigation
Expand file tree
/
Copy pathstripccomments.c
More file actions
245 lines (233 loc) · 7.03 KB
/
Copy pathstripccomments.c
File metadata and controls
245 lines (233 loc) · 7.03 KB
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
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
/**
Strips C- and C++-style comments from stdin, sending the results to
stdout. It assumes that its input is legal C-like code, and does
only little error handling.
It treats string literals as anything starting and ending with
matching double OR single quotes OR backticks (for use with
scripting languages which use those). It assumes that a quote
character within a string which uses the same quote type is escaped
by a backslash. It should not be used on any code which might
contain C/C++ comments inside heredocs, and similar constructs, as
it will strip those out.
Usage: $0 [--keep-first|-k] < input > output
The --keep-first (-k) flag tells it to retain the first comment in the
input stream (which is often a license or attribution block). It
may be given repeatedly, each one incrementing the number of
retained comments by one.
License: Public Domain
Author: Stephan Beal (stephan@wanderinghorse.net)
*/
#include <stdio.h>
#include <assert.h>
#include <string.h>
#if 1
#define MARKER(pfexp) \
do{ printf("MARKER: %s:%d:\t",__FILE__,__LINE__); \
printf pfexp; \
} while(0)
#else
#define MARKER(exp) if(0) printf
#endif
struct {
FILE * input;
FILE * output;
int rc;
int keepFirst;
} App = {
0/*input*/,
0/*output*/,
0/*rc*/,
0/*keepFirst*/
};
void do_it_all(void){
enum states {
S_NONE = 0 /* not in comment */,
S_SLASH1 = 1 /* slash - possibly comment prefix */,
S_CPP = 2 /* in C++ comment */,
S_C = 3 /* in C comment */
};
int ch, prev = EOF;
FILE * out = App.output;
int const slash = '/';
int const star = '*';
int line = 1;
int col = 0;
enum states state = S_NONE /* current state */;
int elide = 0 /* true if currently eliding output */;
int state3Col = -99
/* huge kludge for odd corner case: */
/*/ <--- here. state3Col marks the source column in which a C-style
comment starts, so that it can tell if star-slash inside a
C-style comment is the end of the comment or is the weird corner
case marked at the start of _this_ comment block. */;
for( ; EOF != (ch = fgetc(App.input)); prev = ch,
++col){
switch(state){
case S_NONE:
if('\''==ch || '"'==ch || '`'==ch){
/* Read string literal...
needed to properly catch comments in strings. */
int const quote = ch,
startLine = line, startCol = col;
int ch2, escaped = 0, endOfString = 0;
fputc(ch, out);
for( ++col; !endOfString && EOF != (ch2 = fgetc(App.input));
++col ){
switch(ch2){
case '\\': escaped = !escaped;
break;
case '`':
case '\'':
case '"':
if(!escaped && quote == ch2) endOfString = 1;
escaped = 0;
break;
default:
escaped = 0;
break;
}
if('\n'==ch2){
++line;
col = 0;
}
fputc(ch2, out);
}
if(EOF == ch2){
fprintf(stderr, "Unexpected EOF while reading %s literal "
"on line %d column %d.\n",
('\''==ch) ? "char" : "string",
startLine, startCol);
App.rc = 1;
return;
}
break;
}
else if(slash == ch){
/* MARKER(("state 0 ==> 1 @ %d:%d\n", line, col)); */
if( '\\'==prev ){
/**
JS regexes may contain slash-asterisks, as happened at:
https://github.com/emscripten-core/emscripten/issues/23412
Such regexes will always necessarily be preceded by a
backslash, though.
It is hypothetically possible for a legitimate comment
slash-asterisk to appear immediately before a
backslash, but that seems like an even rarer corner
case than the JS regex case.
*/
fputc(ch, out);
}else{
state = S_SLASH1;
}
break;
}
fputc(ch, out);
break;
case S_SLASH1: /* 1 slash */
/* MARKER(("SLASH1 @ %d:%d App.keepFirst=%d\n",
line, col, App.keepFirst)); */
switch(ch){
case '*':
/* Enter C comment */
if(App.keepFirst>0){
elide = 0;
--App.keepFirst;
}else{
elide = 1;
}
/*MARKER(("state 1 ==> 3 @ %d:%d\n", line, col));*/
state = S_C;
state3Col = col-1;
if(!elide){
fputc(prev, out);
fputc(ch, out);
}
break;
case '/':
/* Enter C++ comment */
if(App.keepFirst>0){
elide = 0;
--App.keepFirst;
}else{
elide = 1;
}
/*MARKER(("state 1 ==> 2 @ %d:%d\n", line, col));*/
state = S_CPP;
if(!elide){
fputc(prev, out);
fputc(ch, out);
}
break;
default:
/* It wasn't a comment after all. */
state = S_NONE;
if(!elide){
fputc(prev, out);
fputc(ch, out);
}
}
break;
case S_CPP: /* C++ comment */
if('\n' == ch){
/* MARKER(("state 2 ==> 0 @ %d:%d\n", line, col)); */
state = S_NONE;
elide = 0;
}
if(!elide){
fputc(ch, out);
}
break;
case S_C: /* C comment */
if(!elide){
fputc(ch, out);
}
if(slash == ch){
if(star == prev){
/* MARKER(("state 3 ==> 0 @ %d:%d\n", line, col)); */
/* Corner case which breaks this: */
/*/ <-- slash there */
/* That shows up twice in a piece of 3rd-party
code i use. */
/* And thus state3Col was introduced :/ */
if(col!=state3Col+2){
state = S_NONE;
elide = 0;
state3Col = -99;
}
}
}
break;
default:
assert(!"impossible!");
break;
}
if('\n' == ch){
++line;
col = 0;
state3Col = -99;
}
}
}
static void usage(char const *zAppName){
fprintf(stderr, "Strips C- and C++-style comments from stdin and sends "
"the results to stdout.\n");
fprintf(stderr, "Usage: %s [--keep-first|-k] < input > output\n", zAppName);
}
int main( int argc, char const * const * argv ){
int i;
for(i = 1; i < argc; ++i){
char const * zArg = argv[i];
while( '-'==*zArg ) ++zArg;
if( 0==strcmp(zArg,"k")
|| 0==strcmp(zArg,"keep-first") ){
++App.keepFirst;
}else{
usage(argv[0]);
return 1;
}
}
App.input = stdin;
App.output = stdout;
do_it_all();
return App.rc ? 1 : 0;
}