dll/win32/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
  37 #pragma once
  38
  39 struct _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))
  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
  52 typedef 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
  58 static inline unsigned jsstr_length(jsstr_t *str)
  59 {
  60     return str->length_flags >> JSSTR_LENGTH_SHIFT;
  61 }
  62
  63 static inline jsstr_tag_t jsstr_tag(jsstr_t *str)
  64 {
  65     return str->length_flags & JSSTR_FLAG_TAG_MASK;
  66 }
  67
  68 static inline BOOL jsstr_is_inline(jsstr_t *str)
  69 {
  70     return jsstr_tag(str) == JSSTR_INLINE;
  71 }
  72
  73 static inline BOOL jsstr_is_heap(jsstr_t *str)
  74 {
  75     return jsstr_tag(str) == JSSTR_HEAP;
  76 }
  77
  78 static inline BOOL jsstr_is_rope(jsstr_t *str)
  79 {
  80     return jsstr_tag(str) == JSSTR_ROPE;
  81 }
  82
  83 typedef struct {
  84     jsstr_t str;
  85     WCHAR buf[1];
  86 } jsstr_inline_t;
  87
  88 typedef struct {
  89     jsstr_t str;
  90     WCHAR *buf;
  91 } jsstr_heap_t;
  92
  93 typedef struct {
  94     jsstr_t str;
  95     jsstr_t *left;
  96     jsstr_t *right;
  97     unsigned depth;
  98 } jsstr_rope_t;
  99
 100 jsstr_t *jsstr_alloc_len(const WCHAR*,unsigned) DECLSPEC_HIDDEN;
 101 WCHAR *jsstr_alloc_buf(unsigned,jsstr_t**) DECLSPEC_HIDDEN;
 102
 103 static inline jsstr_t *jsstr_alloc(const WCHAR *str)
 104 {
 105     return jsstr_alloc_len(str, strlenW(str));
 106 }
 107
 108 void jsstr_free(jsstr_t*) DECLSPEC_HIDDEN;
 109
 110 static inline void jsstr_release(jsstr_t *str)
 111 {
 112     if(!--str->ref) {
 113         if(jsstr_is_inline(str))
 114             heap_free(str);
 115         else
 116             jsstr_free(str);
 117     }
 118 }
 119
 120 static inline jsstr_t *jsstr_addref(jsstr_t *str)
 121 {
 122     str->ref++;
 123     return str;
 124 }
 125
 126 static inline jsstr_inline_t *jsstr_as_inline(jsstr_t *str)
 127 {
 128     return CONTAINING_RECORD(str, jsstr_inline_t, str);
 129 }
 130
 131 static inline jsstr_heap_t *jsstr_as_heap(jsstr_t *str)
 132 {
 133     return CONTAINING_RECORD(str, jsstr_heap_t, str);
 134 }
 135
 136 static inline jsstr_rope_t *jsstr_as_rope(jsstr_t *str)
 137 {
 138     return CONTAINING_RECORD(str, jsstr_rope_t, str);
 139 }
 140
 141 const WCHAR *jsstr_rope_flatten(jsstr_rope_t*) DECLSPEC_HIDDEN;
 142
 143 static inline const WCHAR *jsstr_flatten(jsstr_t *str)
 144 {
 145     return jsstr_is_inline(str) ? jsstr_as_inline(str)->buf
 146         : jsstr_is_heap(str) ? jsstr_as_heap(str)->buf
 147         : jsstr_rope_flatten(jsstr_as_rope(str));
 148 }
 149
 150 void jsstr_extract(jsstr_t*,unsigned,unsigned,WCHAR*) DECLSPEC_HIDDEN;
 151
 152 static inline unsigned jsstr_flush(jsstr_t *str, WCHAR *buf)
 153 {
 154     unsigned len = jsstr_length(str);
 155     if(jsstr_is_inline(str)) {
 156         memcpy(buf, jsstr_as_inline(str)->buf, len*sizeof(WCHAR));
 157     }else if(jsstr_is_heap(str)) {
 158         memcpy(buf, jsstr_as_heap(str)->buf, len*sizeof(WCHAR));
 159     }else {
 160         jsstr_rope_t *rope = jsstr_as_rope(str);
 161         jsstr_flush(rope->left, buf);
 162         jsstr_flush(rope->right, buf+jsstr_length(rope->left));
 163     }
 164     return len;
 165 }
 166
 167 static inline jsstr_t *jsstr_substr(jsstr_t *str, unsigned off, unsigned len)
 168 {
 169     jsstr_t *ret;
 170     WCHAR *ptr;
 171
 172     ptr = jsstr_alloc_buf(len, &ret);
 173     if(ptr)
 174         jsstr_extract(str, off, len, ptr);
 175     return ret;
 176 }
 177
 178 int jsstr_cmp(jsstr_t*,jsstr_t*) DECLSPEC_HIDDEN;
 179
 180 static inline BOOL jsstr_eq(jsstr_t *left, jsstr_t *right)
 181 {
 182     return jsstr_length(left) == jsstr_length(right) && !jsstr_cmp(left, right);
 183 }
 184
 185 jsstr_t *jsstr_concat(jsstr_t*,jsstr_t*) DECLSPEC_HIDDEN;
 186
 187 jsstr_t *jsstr_nan(void) DECLSPEC_HIDDEN;
 188 jsstr_t *jsstr_empty(void) DECLSPEC_HIDDEN;
 189 jsstr_t *jsstr_undefined(void) DECLSPEC_HIDDEN;
 190
 191 jsstr_t *jsstr_null_bstr(void) DECLSPEC_HIDDEN;
 192 BOOL is_null_bstr(jsstr_t*) DECLSPEC_HIDDEN;
 193
 194 BOOL init_strings(void) DECLSPEC_HIDDEN;
 195 void free_strings(void) DECLSPEC_HIDDEN;
 196
 197 const char *debugstr_jsstr(jsstr_t*) DECLSPEC_HIDDEN;