1 /* jsmin.c
2 2019-10-30
3
4 Copyright (C) 2002 Douglas Crockford (www.crockford.com)
5
6 Permission is hereby granted, free of charge, to any person obtaining a copy of
7 this software and associated documentation files (the "Software"), to deal in
8 the Software without restriction, including without limitation the rights to
9 use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
10 of the Software, and to permit persons to whom the Software is furnished to do
11 so, subject to the following conditions:
12
13 The above copyright notice and this permission notice shall be included in all
14 copies or substantial portions of the Software.
15
16 The Software shall be used for Good, not Evil.
17
18 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
21 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
23 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
24 SOFTWARE.
25 */
26
27 #include <stdlib.h>
28 #include <stdio.h>
29
30 static int the_a;
31 static int the_b;
32 static int look_ahead = EOF;
33 static int the_x = EOF;
34 static int the_y = EOF;
35
36
37 static void error(char* string) {
38 fputs("JSMIN Error: ", stderr);
39 fputs(string, stderr);
40 fputc('\n', stderr);
41 exit(1);
42 }
43
44 /* is_alphanum -- return true if the character is a letter, digit, underscore,
45 dollar sign, or non-ASCII character.
46 */
47
48 static int is_alphanum(int codeunit) {
49 return (
50 (codeunit >= 'a' && codeunit <= 'z')
51 || (codeunit >= '0' && codeunit <= '9')
52 || (codeunit >= 'A' && codeunit <= 'Z')
53 || codeunit == '_'
54 || codeunit == '$'
55 || codeunit == '\\'
56 || codeunit > 126
57 );
58 }
59
60
61 /* get -- return the next character from stdin. Watch out for lookahead. If
62 the character is a control character, translate it to a space or
63 linefeed.
64 */
65
66 static int get() {
67 int codeunit = look_ahead;
68 look_ahead = EOF;
69 if (codeunit == EOF) {
70 codeunit = getc(stdin);
71 }
72 if (codeunit >= ' ' || codeunit == '\n' || codeunit == EOF) {
73 return codeunit;
74 }
75 if (codeunit == '\r') {
76 return '\n';
77 }
78 return ' ';
79 }
80
81
82 /* peek -- get the next character without advancing.
83 */
84
85 static int peek() {
86 look_ahead = get();
87 return look_ahead;
88 }
89
90
91 /* next -- get the next character, excluding comments. peek() is used to see
92 if a '/' is followed by a '/' or '*'.
93 */
94
95 static int next() {
96 int codeunit = get();
97 if (codeunit == '/') {
98 switch (peek()) {
99 case '/':
100 for (;;) {
101 codeunit = get();
102 if (codeunit <= '\n') {
103 break;
104 }
105 }
106 break;
107 case '*':
108 get();
109 while (codeunit != ' ') {
110 switch (get()) {
111 case '*':
112 if (peek() == '/') {
113 get();
114 codeunit = ' ';
115 }
116 break;
117 case EOF:
118 error("Unterminated comment.");
119 }
120 }
121 break;
122 }
123 }
124 the_y = the_x;
125 the_x = codeunit;
126 return codeunit;
127 }
128
129
130 /* action -- do something! What you do is determined by the argument:
131 1 Output A. Copy B to A. Get the next B.
132 2 Copy B to A. Get the next B. (Delete A).
133 3 Get the next B. (Delete B).
134 action treats a string as a single character.
135 action recognizes a regular expression if it is preceded by the likes of
136 '(' or ',' or '='.
137 */
138
139 static void action(int determined) {
140 switch (determined) {
141 case 1:
142 putc(the_a, stdout);
143 if (
144 (the_y == '\n' || the_y == ' ')
145 && (the_a == '+' || the_a == '-' || the_a == '*' || the_a == '/')
146 && (the_b == '+' || the_b == '-' || the_b == '*' || the_b == '/')
147 ) {
148 putc(the_y, stdout);
149 }
150 case 2:
151 the_a = the_b;
152 if (the_a == '\'' || the_a == '"' || the_a == '`') {
153 for (;;) {
154 putc(the_a, stdout);
155 the_a = get();
156 if (the_a == the_b) {
157 break;
158 }
159 if (the_a == '\\') {
160 putc(the_a, stdout);
161 the_a = get();
162 }
163 if (the_a == EOF) {
164 error("Unterminated string literal.");
165 }
166 }
167 }
168 case 3:
169 the_b = next();
170 if (the_b == '/' && (
171 the_a == '(' || the_a == ',' || the_a == '=' || the_a == ':'
172 || the_a == '[' || the_a == '!' || the_a == '&' || the_a == '|'
173 || the_a == '?' || the_a == '+' || the_a == '-' || the_a == '~'
174 || the_a == '*' || the_a == '/' || the_a == '{' || the_a == '}'
175 || the_a == ';'
176 )) {
177 putc(the_a, stdout);
178 if (the_a == '/' || the_a == '*') {
179 putc(' ', stdout);
180 }
181 putc(the_b, stdout);
182 for (;;) {
183 the_a = get();
184 if (the_a == '[') {
185 for (;;) {
186 putc(the_a, stdout);
187 the_a = get();
188 if (the_a == ']') {
189 break;
190 }
191 if (the_a == '\\') {
192 putc(the_a, stdout);
193 the_a = get();
194 }
195 if (the_a == EOF) {
196 error(
197 "Unterminated set in Regular Expression literal."
198 );
199 }
200 }
201 } else if (the_a == '/') {
202 switch (peek()) {
203 case '/':
204 case '*':
205 error(
206 "Unterminated set in Regular Expression literal."
207 );
208 }
209 break;
210 } else if (the_a =='\\') {
211 putc(the_a, stdout);
212 the_a = get();
213 }
214 if (the_a == EOF) {
215 error("Unterminated Regular Expression literal.");
216 }
217 putc(the_a, stdout);
218 }
219 the_b = next();
220 }
221 }
222 }
223
224
225 /* jsmin -- Copy the input to the output, deleting the characters which are
226 insignificant to JavaScript. Comments will be removed. Tabs will be
227 replaced with spaces. Carriage returns will be replaced with linefeeds.
228 Most spaces and linefeeds will be removed.
229 */
230
231 static void jsmin() {
232 if (peek() == 0xEF) {
233 get();
234 get();
235 get();
236 }
237 the_a = '\n';
238 action(3);
239 while (the_a != EOF) {
240 switch (the_a) {
241 case ' ':
242 action(
243 is_alphanum(the_b)
244 ? 1
245 : 2
246 );
247 break;
248 case '\n':
249 switch (the_b) {
250 case '{':
251 case '[':
252 case '(':
253 case '+':
254 case '-':
255 case '!':
256 case '~':
257 action(1);
258 break;
259 case ' ':
260 action(3);
261 break;
262 default:
263 action(
264 is_alphanum(the_b)
265 ? 1
266 : 2
267 );
268 }
269 break;
270 default:
271 switch (the_b) {
272 case ' ':
273 action(
274 is_alphanum(the_a)
275 ? 1
276 : 3
277 );
278 break;
279 case '\n':
280 switch (the_a) {
281 case '}':
282 case ']':
283 case ')':
284 case '+':
285 case '-':
286 case '"':
287 case '\'':
288 case '`':
289 action(1);
290 break;
291 default:
292 action(
293 is_alphanum(the_a)
294 ? 1
295 : 3
296 );
297 }
298 break;
299 default:
300 action(1);
301 break;
302 }
303 }
304 }
305 }
306
307
308 /* main -- Output any command line arguments as comments
309 and then minify the input.
310 */
311
312 extern int main(int argc, char* argv[]) {
313 int i;
314 for (i = 1; i < argc; i += 1) {
315 fprintf(stdout, "// %s\n", argv[i]);
316 }
317 jsmin();
318 return 0;
319 }
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