dlls/jscript/jsstr.h

   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 struct _jsstr_t {
  37     unsigned length_flags;
  38     unsigned ref;
  39 };
  40
  41 #define JSSTR_LENGTH_SHIFT 4
  42 #define JSSTR_MAX_LENGTH ((1 << (32-JSSTR_LENGTH_SHIFT))-1)
  43 #define JSSTR_FLAGS_MASK ((1 << JSSTR_LENGTH_SHIFT)-1)
  44
  45 #define JSSTR_FLAG_LBIT     1
  46 #define JSSTR_FLAG_FLAT     2
  47 #define JSSTR_FLAG_TAG_MASK 3
  48
  49 typedef enum {
  50     JSSTR_INLINE = JSSTR_FLAG_FLAT,
  51     JSSTR_HEAP   = JSSTR_FLAG_FLAT|JSSTR_FLAG_LBIT,
  52     JSSTR_ROPE   = JSSTR_FLAG_LBIT
  53 } jsstr_tag_t;
  54
  55 static inline unsigned jsstr_length(jsstr_t *str)
  56 {
  57     return str->length_flags >> JSSTR_LENGTH_SHIFT;
  58 }
  59
  60 static inline jsstr_tag_t jsstr_tag(jsstr_t *str)
  61 {
  62     return str->length_flags & JSSTR_FLAG_TAG_MASK;
  63 }
  64
  65 static inline BOOL jsstr_is_inline(jsstr_t *str)
  66 {
  67     return jsstr_tag(str) == JSSTR_INLINE;
  68 }
  69
  70 static inline BOOL jsstr_is_heap(jsstr_t *str)
  71 {
  72     return jsstr_tag(str) == JSSTR_HEAP;
  73 }
  74
  75 static inline BOOL jsstr_is_rope(jsstr_t *str)
  76 {
  77     return jsstr_tag(str) == JSSTR_ROPE;
  78 }
  79
  80 typedef struct {
  81     jsstr_t str;
  82     WCHAR buf[1];
  83 } jsstr_inline_t;
  84
  85 typedef struct {
  86     jsstr_t str;
  87     WCHAR *buf;
  88 } jsstr_heap_t;
  89
  90 typedef struct {
  91     jsstr_t str;
  92     jsstr_t *left;
  93     jsstr_t *right;
  94     unsigned depth;
  95 } jsstr_rope_t;
  96
  97 jsstr_t *jsstr_alloc_len(const WCHAR*,unsigned) DECLSPEC_HIDDEN;
  98 jsstr_t *jsstr_alloc_buf(unsigned,WCHAR**) DECLSPEC_HIDDEN;
  99
 100 static inline jsstr_t *jsstr_alloc(const WCHAR *str)
 101 {
 102     return jsstr_alloc_len(str, strlenW(str));
 103 }
 104
 105 void jsstr_free(jsstr_t*) DECLSPEC_HIDDEN;
 106
 107 static inline void jsstr_release(jsstr_t *str)
 108 {
 109     if(!--str->ref)
 110         jsstr_free(str);
 111 }
 112
 113 static inline jsstr_t *jsstr_addref(jsstr_t *str)
 114 {
 115     str->ref++;
 116     return str;
 117 }
 118
 119 static inline jsstr_inline_t *jsstr_as_inline(jsstr_t *str)
 120 {
 121     return CONTAINING_RECORD(str, jsstr_inline_t, str);
 122 }
 123
 124 static inline jsstr_heap_t *jsstr_as_heap(jsstr_t *str)
 125 {
 126     return CONTAINING_RECORD(str, jsstr_heap_t, str);
 127 }
 128
 129 static inline jsstr_rope_t *jsstr_as_rope(jsstr_t *str)
 130 {
 131     return CONTAINING_RECORD(str, jsstr_rope_t, str);
 132 }
 133
 134 const WCHAR *jsstr_rope_flatten(jsstr_rope_t*) DECLSPEC_HIDDEN;
 135
 136 static inline const WCHAR *jsstr_flatten(jsstr_t *str)
 137 {
 138     return jsstr_is_inline(str) ? jsstr_as_inline(str)->buf
 139         : jsstr_is_heap(str) ? jsstr_as_heap(str)->buf
 140         : jsstr_rope_flatten(jsstr_as_rope(str));
 141 }
 142
 143 void jsstr_extract(jsstr_t*,unsigned,unsigned,WCHAR*) DECLSPEC_HIDDEN;
 144
 145 static inline unsigned jsstr_flush(jsstr_t *str, WCHAR *buf)
 146 {
 147     unsigned len = jsstr_length(str);
 148     if(jsstr_is_inline(str)) {
 149         memcpy(buf, jsstr_as_inline(str)->buf, len*sizeof(WCHAR));
 150     }else if(jsstr_is_heap(str)) {
 151         memcpy(buf, jsstr_as_heap(str)->buf, len*sizeof(WCHAR));
 152     }else {
 153         jsstr_rope_t *rope = jsstr_as_rope(str);
 154         jsstr_flush(rope->left, buf);
 155         jsstr_flush(rope->right, buf+jsstr_length(rope->left));
 156     }
 157     return len;
 158 }
 159
 160 static inline jsstr_t *jsstr_substr(jsstr_t *str, unsigned off, unsigned len)
 161 {
 162     jsstr_t *ret;
 163     WCHAR *ptr;
 164
 165     ret = jsstr_alloc_buf(len, &ptr);
 166     if(ret)
 167         jsstr_extract(str, off, len, ptr);
 168     return ret;
 169 }
 170
 171 int jsstr_cmp(jsstr_t*,jsstr_t*) DECLSPEC_HIDDEN;
 172
 173 static inline BOOL jsstr_eq(jsstr_t *left, jsstr_t *right)
 174 {
 175     return jsstr_length(left) == jsstr_length(right) && !jsstr_cmp(left, right);
 176 }
 177
 178 jsstr_t *jsstr_concat(jsstr_t*,jsstr_t*) DECLSPEC_HIDDEN;
 179
 180 jsstr_t *jsstr_nan(void) DECLSPEC_HIDDEN;
 181 jsstr_t *jsstr_empty(void) DECLSPEC_HIDDEN;
 182 jsstr_t *jsstr_undefined(void) DECLSPEC_HIDDEN;
 183
 184 jsstr_t *jsstr_null_bstr(void) DECLSPEC_HIDDEN;
 185 BOOL is_null_bstr(jsstr_t*) DECLSPEC_HIDDEN;
 186
 187 BOOL init_strings(void) DECLSPEC_HIDDEN;
 188 void free_strings(void) DECLSPEC_HIDDEN;
 189
 190 const char *debugstr_jsstr(jsstr_t*) DECLSPEC_HIDDEN;