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Reactos
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/*
20 * jsstr_t is a common header for all string representations. The exact layout of the string
21 * representation may be:
22 *
23 * - inline string - string bytes directly follow string headers.
24 * - heap string - a structure containing a pointer to buffer on the heap.
25 * - roper string - a product of concatenation of two strings. Instead of copying whole
26 * buffers, we may store just references to concatenated strings.
27 *
28 * String layout may change over life time of the string. Currently possible transformation
29 * is when a rope string becomes a heap stream. That happens when we need a real, linear
30 * zero-terminated buffer (a flat buffer). At this point the type of the string is changed
31 * and the new buffer is stored in the string, so that subsequent operations requiring
32 * a flat string won't need to flatten it again.
33 *
34 * In the future more layouts and transformations may be added.
35 */
36
37#pragma once
38
39struct _jsstr_t {
40 unsigned length_flags;
41 unsigned ref;
42};
43
44#define JSSTR_LENGTH_SHIFT 4
45#define JSSTR_MAX_LENGTH ((1 << (32-JSSTR_LENGTH_SHIFT))-1)
46#define JSSTR_FLAGS_MASK ((1 << JSSTR_LENGTH_SHIFT)-1)
47
48#define JSSTR_FLAG_LBIT 1
49#define JSSTR_FLAG_FLAT 2
50#define JSSTR_FLAG_TAG_MASK 3
51
52typedef enum {
53 JSSTR_INLINE = JSSTR_FLAG_FLAT,
54 JSSTR_HEAP = JSSTR_FLAG_FLAT|JSSTR_FLAG_LBIT,
55 JSSTR_ROPE = JSSTR_FLAG_LBIT
56} jsstr_tag_t;
57
58static inline unsigned jsstr_length(jsstr_t *str)
59{
60 return str->length_flags >> JSSTR_LENGTH_SHIFT;
61}
62
63static inline jsstr_tag_t jsstr_tag(jsstr_t *str)
64{
65 return str->length_flags & JSSTR_FLAG_TAG_MASK;
66}
67
68static inline BOOL jsstr_is_inline(jsstr_t *str)
69{
70 return jsstr_tag(str) == JSSTR_INLINE;
71}
72
73static inline BOOL jsstr_is_heap(jsstr_t *str)
74{
75 return jsstr_tag(str) == JSSTR_HEAP;
76}
77
78static inline BOOL jsstr_is_rope(jsstr_t *str)
79{
80 return jsstr_tag(str) == JSSTR_ROPE;
81}
82
83typedef struct {
84 jsstr_t str;
85 WCHAR buf[1];
86} jsstr_inline_t;
87
88typedef struct {
89 jsstr_t str;
90 WCHAR *buf;
91} jsstr_heap_t;
92
93typedef struct {
94 jsstr_t str;
95 jsstr_t *left;
96 jsstr_t *right;
97 unsigned depth;
98} jsstr_rope_t;
99
100jsstr_t *jsstr_alloc_len(const WCHAR*,unsigned) DECLSPEC_HIDDEN;
101jsstr_t *jsstr_alloc_buf(unsigned,WCHAR**) DECLSPEC_HIDDEN;
102
103static inline jsstr_t *jsstr_alloc(const WCHAR *str)
104{
105 return jsstr_alloc_len(str, lstrlenW(str));
106}
107
108void jsstr_free(jsstr_t*) DECLSPEC_HIDDEN;
109
110static inline void jsstr_release(jsstr_t *str)
111{
112 if(!--str->ref)
113 jsstr_free(str);
114}
115
116static inline jsstr_t *jsstr_addref(jsstr_t *str)
117{
118 str->ref++;
119 return str;
120}
121
122static inline jsstr_inline_t *jsstr_as_inline(jsstr_t *str)
123{
124 return CONTAINING_RECORD(str, jsstr_inline_t, str);
125}
126
127static inline jsstr_heap_t *jsstr_as_heap(jsstr_t *str)
128{
129 return CONTAINING_RECORD(str, jsstr_heap_t, str);
130}
131
132static inline jsstr_rope_t *jsstr_as_rope(jsstr_t *str)
133{
134 return CONTAINING_RECORD(str, jsstr_rope_t, str);
135}
136
137const WCHAR *jsstr_rope_flatten(jsstr_rope_t*) DECLSPEC_HIDDEN;
138
139static inline const WCHAR *jsstr_flatten(jsstr_t *str)
140{
141 return jsstr_is_inline(str) ? jsstr_as_inline(str)->buf
142 : jsstr_is_heap(str) ? jsstr_as_heap(str)->buf
143 : jsstr_rope_flatten(jsstr_as_rope(str));
144}
145
146void jsstr_extract(jsstr_t*,unsigned,unsigned,WCHAR*) DECLSPEC_HIDDEN;
147
148static inline unsigned jsstr_flush(jsstr_t *str, WCHAR *buf)
149{
150 unsigned len = jsstr_length(str);
151 if(jsstr_is_inline(str)) {
152 memcpy(buf, jsstr_as_inline(str)->buf, len*sizeof(WCHAR));
153 }else if(jsstr_is_heap(str)) {
154 memcpy(buf, jsstr_as_heap(str)->buf, len*sizeof(WCHAR));
155 }else {
156 jsstr_rope_t *rope = jsstr_as_rope(str);
157 jsstr_flush(rope->left, buf);
158 jsstr_flush(rope->right, buf+jsstr_length(rope->left));
159 }
160 return len;
161}
162
163static inline jsstr_t *jsstr_substr(jsstr_t *str, unsigned off, unsigned len)
164{
165 jsstr_t *ret;
166 WCHAR *ptr;
167
168 ret = jsstr_alloc_buf(len, &ptr);
169 if(ret)
170 jsstr_extract(str, off, len, ptr);
171 return ret;
172}
173
174int jsstr_cmp(jsstr_t*,jsstr_t*) DECLSPEC_HIDDEN;
175
176static inline BOOL jsstr_eq(jsstr_t *left, jsstr_t *right)
177{
178 return jsstr_length(left) == jsstr_length(right) && !jsstr_cmp(left, right);
179}
180
181jsstr_t *jsstr_concat(jsstr_t*,jsstr_t*) DECLSPEC_HIDDEN;
182
183jsstr_t *jsstr_nan(void) DECLSPEC_HIDDEN;
184jsstr_t *jsstr_empty(void) DECLSPEC_HIDDEN;
185jsstr_t *jsstr_undefined(void) DECLSPEC_HIDDEN;
186
187jsstr_t *jsstr_null_bstr(void) DECLSPEC_HIDDEN;
188BOOL is_null_bstr(jsstr_t*) DECLSPEC_HIDDEN;
189
190BOOL init_strings(void) DECLSPEC_HIDDEN;
191void free_strings(void) DECLSPEC_HIDDEN;
192
193const char *debugstr_jsstr(jsstr_t*) DECLSPEC_HIDDEN;