xref: /reactos/dll/win32/jscript/jsstr.c (revision bae2bac6)
1 /*
2  * Copyright 2012 Jacek Caban for CodeWeavers
3  *
4  * This library is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation; either
7  * version 2.1 of the License, or (at your option) any later version.
8  *
9  * This library is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12  * Lesser General Public License for more details.
13  *
14  * You should have received a copy of the GNU Lesser General Public
15  * License along with this library; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
17  */
18 
19 #include <assert.h>
20 
21 #include "jscript.h"
22 
23 #include "wine/debug.h"
24 
25 /*
26  * This is the length of a string that is considered to be long enough to be
27  * worth the rope to avoid copy.
28  * This probably could be tuned, but keep it low for a while to better test rope's code.
29  */
30 #define JSSTR_SHORT_STRING_LENGTH 8
31 
32 /*
33  * This is the max rope depth. While faster to allocate, ropes may become slow at access.
34  */
35 #define JSSTR_MAX_ROPE_DEPTH 100
36 
37 const char *debugstr_jsstr(jsstr_t *str)
38 {
39     return jsstr_is_inline(str) ? debugstr_wn(jsstr_as_inline(str)->buf, jsstr_length(str))
40         : jsstr_is_heap(str) ? debugstr_wn(jsstr_as_heap(str)->buf, jsstr_length(str))
41         : wine_dbg_sprintf("%s...", debugstr_jsstr(jsstr_as_rope(str)->left));
42 }
43 
44 void jsstr_free(jsstr_t *str)
45 {
46     switch(jsstr_tag(str)) {
47     case JSSTR_HEAP:
48         heap_free(jsstr_as_heap(str)->buf);
49         break;
50     case JSSTR_ROPE: {
51         jsstr_rope_t *rope = jsstr_as_rope(str);
52         jsstr_release(rope->left);
53         jsstr_release(rope->right);
54         break;
55     }
56     case JSSTR_INLINE:
57         break;
58     }
59 
60     heap_free(str);
61 }
62 
63 static inline void jsstr_init(jsstr_t *str, unsigned len, jsstr_tag_t tag)
64 {
65     str->length_flags = len << JSSTR_LENGTH_SHIFT | tag;
66     str->ref = 1;
67 }
68 
69 jsstr_t *jsstr_alloc_buf(unsigned len, WCHAR **buf)
70 {
71     jsstr_inline_t *ret;
72 
73     if(len > JSSTR_MAX_LENGTH)
74         return NULL;
75 
76     ret = heap_alloc(FIELD_OFFSET(jsstr_inline_t, buf[len+1]));
77     if(!ret)
78         return NULL;
79 
80     jsstr_init(&ret->str, len, JSSTR_INLINE);
81     ret->buf[len] = 0;
82     *buf = ret->buf;
83     return &ret->str;
84 }
85 
86 jsstr_t *jsstr_alloc_len(const WCHAR *buf, unsigned len)
87 {
88     jsstr_t *ret;
89     WCHAR *ptr;
90 
91     ret = jsstr_alloc_buf(len, &ptr);
92     if(ret)
93         memcpy(ptr, buf, len*sizeof(WCHAR));
94 
95     return ret;
96 }
97 
98 static void jsstr_rope_extract(jsstr_rope_t *str, unsigned off, unsigned len, WCHAR *buf)
99 {
100     unsigned left_len = jsstr_length(str->left);
101 
102     if(left_len <= off) {
103         jsstr_extract(str->right, off-left_len, len, buf);
104     }else if(left_len >= len+off) {
105         jsstr_extract(str->left, off, len, buf);
106     }else {
107         left_len -= off;
108         jsstr_extract(str->left, off, left_len, buf);
109         jsstr_extract(str->right, 0, len-left_len, buf+left_len);
110     }
111 }
112 
113 void jsstr_extract(jsstr_t *str, unsigned off, unsigned len, WCHAR *buf)
114 {
115     switch(jsstr_tag(str)) {
116     case JSSTR_INLINE:
117         memcpy(buf, jsstr_as_inline(str)->buf+off, len*sizeof(WCHAR));
118         return;
119     case JSSTR_HEAP:
120         memcpy(buf, jsstr_as_heap(str)->buf+off, len*sizeof(WCHAR));
121         return;
122     case JSSTR_ROPE:
123         jsstr_rope_extract(jsstr_as_rope(str), off, len, buf);
124         return;
125     }
126 }
127 
128 static int jsstr_cmp_str(jsstr_t *jsstr, const WCHAR *str, unsigned len)
129 {
130     int ret;
131 
132     switch(jsstr_tag(jsstr)) {
133     case JSSTR_INLINE:
134         ret = memcmp(jsstr_as_inline(jsstr)->buf, str, len*sizeof(WCHAR));
135         return ret || jsstr_length(jsstr) == len ? ret : 1;
136     case JSSTR_HEAP:
137         ret = memcmp(jsstr_as_heap(jsstr)->buf, str, len*sizeof(WCHAR));
138         return ret || jsstr_length(jsstr) == len ? ret : 1;
139     case JSSTR_ROPE: {
140         jsstr_rope_t *rope = jsstr_as_rope(jsstr);
141         unsigned left_len = jsstr_length(rope->left);
142 
143         ret = jsstr_cmp_str(rope->left, str, min(len, left_len));
144         if(ret || len <= left_len)
145             return ret;
146         return jsstr_cmp_str(rope->right, str+left_len, len-left_len);
147     }
148     }
149 
150     assert(0);
151     return 0;
152 }
153 
154 #define TMP_BUF_SIZE 256
155 
156 static int ropes_cmp(jsstr_rope_t *left, jsstr_rope_t *right)
157 {
158     WCHAR left_buf[TMP_BUF_SIZE], right_buf[TMP_BUF_SIZE];
159     unsigned left_len = jsstr_length(&left->str);
160     unsigned right_len = jsstr_length(&right->str);
161     unsigned cmp_off = 0, cmp_size;
162     int ret;
163 
164     /* FIXME: We can avoid temporary buffers here. */
165     while(cmp_off < min(left_len, right_len)) {
166         cmp_size = min(left_len, right_len) - cmp_off;
167         if(cmp_size > TMP_BUF_SIZE)
168             cmp_size = TMP_BUF_SIZE;
169 
170         jsstr_rope_extract(left, cmp_off, cmp_size, left_buf);
171         jsstr_rope_extract(right, cmp_off, cmp_size, right_buf);
172         ret = memcmp(left_buf, right_buf, cmp_size);
173         if(ret)
174             return ret;
175 
176         cmp_off += cmp_size;
177     }
178 
179     return left_len - right_len;
180 }
181 
182 static inline const WCHAR *jsstr_try_flat(jsstr_t *str)
183 {
184     return jsstr_is_inline(str) ? jsstr_as_inline(str)->buf
185         : jsstr_is_heap(str) ? jsstr_as_heap(str)->buf
186         : NULL;
187 }
188 
189 int jsstr_cmp(jsstr_t *str1, jsstr_t *str2)
190 {
191     unsigned len1 = jsstr_length(str1);
192     unsigned len2 = jsstr_length(str2);
193     const WCHAR *str;
194     int ret;
195 
196     str = jsstr_try_flat(str2);
197     if(str) {
198         ret = jsstr_cmp_str(str1, str, min(len1, len2));
199         return ret || len1 == len2 ? ret : -1;
200     }
201 
202     str = jsstr_try_flat(str1);
203     if(str) {
204         ret = jsstr_cmp_str(str2, str, min(len1, len2));
205         return ret || len1 == len2 ? -ret : 1;
206     }
207 
208     return ropes_cmp(jsstr_as_rope(str1), jsstr_as_rope(str2));
209 }
210 
211 jsstr_t *jsstr_concat(jsstr_t *str1, jsstr_t *str2)
212 {
213     unsigned len1, len2;
214     jsstr_t *ret;
215     WCHAR *ptr;
216 
217     len1 = jsstr_length(str1);
218     if(!len1)
219         return jsstr_addref(str2);
220 
221     len2 = jsstr_length(str2);
222     if(!len2)
223         return jsstr_addref(str1);
224 
225     if(len1 + len2 >= JSSTR_SHORT_STRING_LENGTH) {
226         unsigned depth, depth2;
227         jsstr_rope_t *rope;
228 
229         depth = jsstr_is_rope(str1) ? jsstr_as_rope(str1)->depth : 0;
230         depth2 = jsstr_is_rope(str2) ? jsstr_as_rope(str2)->depth : 0;
231         if(depth2 > depth)
232             depth = depth2;
233 
234         if(depth++ < JSSTR_MAX_ROPE_DEPTH) {
235             if(len1+len2 > JSSTR_MAX_LENGTH)
236                 return NULL;
237 
238             rope = heap_alloc(sizeof(*rope));
239             if(!rope)
240                 return NULL;
241 
242             jsstr_init(&rope->str, len1+len2, JSSTR_ROPE);
243             rope->left = jsstr_addref(str1);
244             rope->right = jsstr_addref(str2);
245             rope->depth = depth;
246             return &rope->str;
247         }
248     }
249 
250     ret = jsstr_alloc_buf(len1+len2, &ptr);
251     if(!ret)
252         return NULL;
253 
254     jsstr_flush(str1, ptr);
255     jsstr_flush(str2, ptr+len1);
256     return ret;
257 
258 }
259 
260 C_ASSERT(sizeof(jsstr_heap_t) <= sizeof(jsstr_rope_t));
261 
262 const WCHAR *jsstr_rope_flatten(jsstr_rope_t *str)
263 {
264     WCHAR *buf;
265 
266     buf = heap_alloc((jsstr_length(&str->str)+1) * sizeof(WCHAR));
267     if(!buf)
268         return NULL;
269 
270     jsstr_flush(str->left, buf);
271     jsstr_flush(str->right, buf+jsstr_length(str->left));
272     buf[jsstr_length(&str->str)] = 0;
273 
274     /* Trasform to heap string */
275     jsstr_release(str->left);
276     jsstr_release(str->right);
277     str->str.length_flags |= JSSTR_FLAG_FLAT;
278     return jsstr_as_heap(&str->str)->buf = buf;
279 }
280 
281 static jsstr_t *empty_str, *nan_str, *undefined_str, *null_bstr_str;
282 
283 jsstr_t *jsstr_nan(void)
284 {
285     return jsstr_addref(nan_str);
286 }
287 
288 jsstr_t *jsstr_empty(void)
289 {
290     return jsstr_addref(empty_str);
291 }
292 
293 jsstr_t *jsstr_undefined(void)
294 {
295     return jsstr_addref(undefined_str);
296 }
297 
298 jsstr_t *jsstr_null_bstr(void)
299 {
300     return jsstr_addref(null_bstr_str);
301 }
302 
303 BOOL is_null_bstr(jsstr_t *str)
304 {
305     return str == null_bstr_str;
306 }
307 
308 BOOL init_strings(void)
309 {
310     static const WCHAR NaNW[] = { 'N','a','N',0 };
311     static const WCHAR undefinedW[] = {'u','n','d','e','f','i','n','e','d',0};
312     WCHAR *ptr;
313 
314     if(!(empty_str = jsstr_alloc_buf(0, &ptr)))
315         return FALSE;
316     if(!(nan_str = jsstr_alloc(NaNW)))
317         return FALSE;
318     if(!(undefined_str = jsstr_alloc(undefinedW)))
319         return FALSE;
320     if(!(null_bstr_str = jsstr_alloc_buf(0, &ptr)))
321         return FALSE;
322      return TRUE;
323 }
324 
325 void free_strings(void)
326 {
327     if(empty_str)
328         jsstr_release(empty_str);
329     if(nan_str)
330         jsstr_release(nan_str);
331     if(undefined_str)
332         jsstr_release(undefined_str);
333     if(null_bstr_str)
334         jsstr_release(null_bstr_str);
335 }
336