src/glsl/ralloc.h

   1 /*
   2  * Copyright © 2010 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23
  24 /**
  25  * \file ralloc.h
  26  *
  27  * ralloc: a recursive memory allocator
  28  *
  29  * The ralloc memory allocator creates a hierarchy of allocated
  30  * objects. Every allocation is in reference to some parent, and
  31  * every allocated object can in turn be used as the parent of a
  32  * subsequent allocation. This allows for extremely convenient
  33  * discarding of an entire tree/sub-tree of allocations by calling
  34  * ralloc_free on any particular object to free it and all of its
  35  * children.
  36  *
  37  * The conceptual working of ralloc was directly inspired by Andrew
  38  * Tridgell's talloc, but ralloc is an independent implementation
  39  * released under the MIT license and tuned for Mesa.
  40  *
  41  * talloc is more sophisticated than ralloc in that it includes reference
  42  * counting and useful debugging features.  However, it is released under
  43  * a non-permissive open source license.
  44  */
  45
  46 #ifndef RALLOC_H
  47 #define RALLOC_H
  48
  49 #ifdef __cplusplus
  50 extern "C" {
  51 #endif
  52
  53 #include <stddef.h>
  54 #include <stdarg.h>
  55 #include <stdbool.h>
  56 #include "main/compiler.h"
  57
  58 /**
  59  * \def ralloc(ctx, type)
  60  * Allocate a new object chained off of the given context.
  61  *
  62  * This is equivalent to:
  63  * \code
  64  * ((type *) ralloc_size(ctx, sizeof(type))
  65  * \endcode
  66  */
  67 #define ralloc(ctx, type)  ((type *) ralloc_size(ctx, sizeof(type)))
  68
  69 /**
  70  * \def rzalloc(ctx, type)
  71  * Allocate a new object out of the given context and initialize it to zero.
  72  *
  73  * This is equivalent to:
  74  * \code
  75  * ((type *) rzalloc_size(ctx, sizeof(type))
  76  * \endcode
  77  */
  78 #define rzalloc(ctx, type) ((type *) rzalloc_size(ctx, sizeof(type)))
  79
  80 /**
  81  * Allocate a new ralloc context.
  82  *
  83  * While any ralloc'd pointer can be used as a context, sometimes it is useful
  84  * to simply allocate a context with no associated memory.
  85  *
  86  * It is equivalent to:
  87  * \code
  88  * ((type *) ralloc_size(ctx, 0)
  89  * \endcode
  90  */
  91 void *ralloc_context(const void *ctx);
  92
  93 /**
  94  * Allocate memory chained off of the given context.
  95  *
  96  * This is the core allocation routine which is used by all others.  It
  97  * simply allocates storage for \p size bytes and returns the pointer,
  98  * similar to \c malloc.
  99  */
 100 void *ralloc_size(const void *ctx, size_t size);
 101
 102 /**
 103  * Allocate zero-initialized memory chained off of the given context.
 104  *
 105  * This is similar to \c calloc with a size of 1.
 106  */
 107 void *rzalloc_size(const void *ctx, size_t size);
 108
 109 /**
 110  * Resize a piece of ralloc-managed memory, preserving data.
 111  *
 112  * Similar to \c realloc.  Unlike C89, passing 0 for \p size does not free the
 113  * memory.  Instead, it resizes it to a 0-byte ralloc context, just like
 114  * calling ralloc_size(ctx, 0).  This is different from talloc.
 115  *
 116  * \param ctx  The context to use for new allocation.  If \p ptr != NULL,
 117  *             it must be the same as ralloc_parent(\p ptr).
 118  * \param ptr  Pointer to the memory to be resized.  May be NULL.
 119  * \param size The amount of memory to allocate, in bytes.
 120  */
 121 void *reralloc_size(const void *ctx, void *ptr, size_t size);
 122
 123 /// \defgroup array Array Allocators @{
 124
 125 /**
 126  * \def ralloc_array(ctx, type, count)
 127  * Allocate an array of objects chained off the given context.
 128  *
 129  * Similar to \c calloc, but does not initialize the memory to zero.
 130  *
 131  * More than a convenience function, this also checks for integer overflow when
 132  * multiplying \c sizeof(type) and \p count.  This is necessary for security.
 133  *
 134  * This is equivalent to:
 135  * \code
 136  * ((type *) ralloc_array_size(ctx, sizeof(type), count)
 137  * \endcode
 138  */
 139 #define ralloc_array(ctx, type, count) \
 140    ((type *) ralloc_array_size(ctx, sizeof(type), count))
 141
 142 /**
 143  * \def rzalloc_array(ctx, type, count)
 144  * Allocate a zero-initialized array chained off the given context.
 145  *
 146  * Similar to \c calloc.
 147  *
 148  * More than a convenience function, this also checks for integer overflow when
 149  * multiplying \c sizeof(type) and \p count.  This is necessary for security.
 150  *
 151  * This is equivalent to:
 152  * \code
 153  * ((type *) rzalloc_array_size(ctx, sizeof(type), count)
 154  * \endcode
 155  */
 156 #define rzalloc_array(ctx, type, count) \
 157    ((type *) rzalloc_array_size(ctx, sizeof(type), count))
 158
 159 /**
 160  * \def reralloc(ctx, ptr, type, count)
 161  * Resize a ralloc-managed array, preserving data.
 162  *
 163  * Similar to \c realloc.  Unlike C89, passing 0 for \p size does not free the
 164  * memory.  Instead, it resizes it to a 0-byte ralloc context, just like
 165  * calling ralloc_size(ctx, 0).  This is different from talloc.
 166  *
 167  * More than a convenience function, this also checks for integer overflow when
 168  * multiplying \c sizeof(type) and \p count.  This is necessary for security.
 169  *
 170  * \param ctx   The context to use for new allocation.  If \p ptr != NULL,
 171  *              it must be the same as ralloc_parent(\p ptr).
 172  * \param ptr   Pointer to the array to be resized.  May be NULL.
 173  * \param type  The element type.
 174  * \param count The number of elements to allocate.
 175  */
 176 #define reralloc(ctx, ptr, type, count) \
 177    ((type *) reralloc_array_size(ctx, ptr, sizeof(type), count))
 178
 179 /**
 180  * Allocate memory for an array chained off the given context.
 181  *
 182  * Similar to \c calloc, but does not initialize the memory to zero.
 183  *
 184  * More than a convenience function, this also checks for integer overflow when
 185  * multiplying \p size and \p count.  This is necessary for security.
 186  */
 187 void *ralloc_array_size(const void *ctx, size_t size, unsigned count);
 188
 189 /**
 190  * Allocate a zero-initialized array chained off the given context.
 191  *
 192  * Similar to \c calloc.
 193  *
 194  * More than a convenience function, this also checks for integer overflow when
 195  * multiplying \p size and \p count.  This is necessary for security.
 196  */
 197 void *rzalloc_array_size(const void *ctx, size_t size, unsigned count);
 198
 199 /**
 200  * Resize a ralloc-managed array, preserving data.
 201  *
 202  * Similar to \c realloc.  Unlike C89, passing 0 for \p size does not free the
 203  * memory.  Instead, it resizes it to a 0-byte ralloc context, just like
 204  * calling ralloc_size(ctx, 0).  This is different from talloc.
 205  *
 206  * More than a convenience function, this also checks for integer overflow when
 207  * multiplying \c sizeof(type) and \p count.  This is necessary for security.
 208  *
 209  * \param ctx   The context to use for new allocation.  If \p ptr != NULL,
 210  *              it must be the same as ralloc_parent(\p ptr).
 211  * \param ptr   Pointer to the array to be resized.  May be NULL.
 212  * \param size  The size of an individual element.
 213  * \param count The number of elements to allocate.
 214  *
 215  * \return True unless allocation failed.
 216  */
 217 void *reralloc_array_size(const void *ctx, void *ptr, size_t size,
 218                           unsigned count);
 219 /// @}
 220
 221 /**
 222  * Free a piece of ralloc-managed memory.
 223  *
 224  * This will also free the memory of any children allocated this context.
 225  */
 226 void ralloc_free(void *ptr);
 227
 228 /**
 229  * "Steal" memory from one context, changing it to another.
 230  *
 231  * This changes \p ptr's context to \p new_ctx.  This is quite useful if
 232  * memory is allocated out of a temporary context.
 233  */
 234 void ralloc_steal(const void *new_ctx, void *ptr);
 235
 236 /**
 237  * Return the given pointer's ralloc context.
 238  */
 239 void *ralloc_parent(const void *ptr);
 240
 241 /**
 242  * Return a context whose memory will be automatically freed at program exit.
 243  *
 244  * The first call to this function creates a context and registers a handler
 245  * to free it using \c atexit.  This may cause trouble if used in a library
 246  * loaded with \c dlopen.
 247  */
 248 void *ralloc_autofree_context(void);
 249
 250 /**
 251  * Set a callback to occur just before an object is freed.
 252  */
 253 void ralloc_set_destructor(const void *ptr, void(*destructor)(void *));
 254
 255 /// \defgroup array String Functions @{
 256 /**
 257  * Duplicate a string, allocating the memory from the given context.
 258  */
 259 char *ralloc_strdup(const void *ctx, const char *str);
 260
 261 /**
 262  * Duplicate a string, allocating the memory from the given context.
 263  *
 264  * Like \c strndup, at most \p n characters are copied.  If \p str is longer
 265  * than \p n characters, \p n are copied, and a termining \c '\0' byte is added.
 266  */
 267 char *ralloc_strndup(const void *ctx, const char *str, size_t n);
 268
 269 /**
 270  * Concatenate two strings, allocating the necessary space.
 271  *
 272  * This appends \p str to \p *dest, similar to \c strcat, using ralloc_resize
 273  * to expand \p *dest to the appropriate size.  \p dest will be updated to the
 274  * new pointer unless allocation fails.
 275  *
 276  * The result will always be null-terminated.
 277  *
 278  * \return True unless allocation failed.
 279  */
 280 bool ralloc_strcat(char **dest, const char *str);
 281
 282 /**
 283  * Concatenate two strings, allocating the necessary space.
 284  *
 285  * This appends at most \p n bytes of \p str to \p *dest, using ralloc_resize
 286  * to expand \p *dest to the appropriate size.  \p dest will be updated to the
 287  * new pointer unless allocation fails.
 288  *
 289  * The result will always be null-terminated; \p str does not need to be null
 290  * terminated if it is longer than \p n.
 291  *
 292  * \return True unless allocation failed.
 293  */
 294 bool ralloc_strncat(char **dest, const char *str, size_t n);
 295
 296 /**
 297  * Print to a string.
 298  *
 299  * This is analogous to \c sprintf, but allocates enough space (using \p ctx
 300  * as the context) for the resulting string.
 301  *
 302  * \return The newly allocated string.
 303  */
 304 char *ralloc_asprintf (const void *ctx, const char *fmt, ...) PRINTFLIKE(2, 3);
 305
 306 /**
 307  * Print to a string, given a va_list.
 308  *
 309  * This is analogous to \c vsprintf, but allocates enough space (using \p ctx
 310  * as the context) for the resulting string.
 311  *
 312  * \return The newly allocated string.
 313  */
 314 char *ralloc_vasprintf(const void *ctx, const char *fmt, va_list args);
 315
 316 /**
 317  * Rewrite the tail of an existing string, starting at a given index.
 318  *
 319  * Overwrites the contents of *str starting at \p start with newly formatted
 320  * text, including a new null-terminator.  Allocates more memory as necessary.
 321  *
 322  * This can be used to append formatted text when the length of the existing
 323  * string is already known, saving a strlen() call.
 324  *
 325  * \sa ralloc_asprintf_append
 326  *
 327  * \param str   The string to be updated.
 328  * \param start The index to start appending new data at.
 329  * \param fmt   A printf-style formatting string
 330  *
 331  * \p str will be updated to the new pointer unless allocation fails.
 332  * \p start will be increased by the length of the newly formatted text.
 333  *
 334  * \return True unless allocation failed.
 335  */
 336 bool ralloc_asprintf_rewrite_tail(char **str, size_t *start,
 337                                   const char *fmt, ...)
 338                                   PRINTFLIKE(3, 4);
 339
 340 /**
 341  * Rewrite the tail of an existing string, starting at a given index.
 342  *
 343  * Overwrites the contents of *str starting at \p start with newly formatted
 344  * text, including a new null-terminator.  Allocates more memory as necessary.
 345  *
 346  * This can be used to append formatted text when the length of the existing
 347  * string is already known, saving a strlen() call.
 348  *
 349  * \sa ralloc_vasprintf_append
 350  *
 351  * \param str   The string to be updated.
 352  * \param start The index to start appending new data at.
 353  * \param fmt   A printf-style formatting string
 354  * \param args  A va_list containing the data to be formatted
 355  *
 356  * \p str will be updated to the new pointer unless allocation fails.
 357  * \p start will be increased by the length of the newly formatted text.
 358  *
 359  * \return True unless allocation failed.
 360  */
 361 bool ralloc_vasprintf_rewrite_tail(char **str, size_t *start, const char *fmt,
 362                                    va_list args);
 363
 364 /**
 365  * Append formatted text to the supplied string.
 366  *
 367  * This is equivalent to
 368  * \code
 369  * ralloc_asprintf_rewrite_tail(str, strlen(*str), fmt, ...)
 370  * \endcode
 371  *
 372  * \sa ralloc_asprintf
 373  * \sa ralloc_asprintf_rewrite_tail
 374  * \sa ralloc_strcat
 375  *
 376  * \p str will be updated to the new pointer unless allocation fails.
 377  *
 378  * \return True unless allocation failed.
 379  */
 380 bool ralloc_asprintf_append (char **str, const char *fmt, ...)
 381                              PRINTFLIKE(2, 3);
 382
 383 /**
 384  * Append formatted text to the supplied string, given a va_list.
 385  *
 386  * This is equivalent to
 387  * \code
 388  * ralloc_vasprintf_rewrite_tail(str, strlen(*str), fmt, args)
 389  * \endcode
 390  *
 391  * \sa ralloc_vasprintf
 392  * \sa ralloc_vasprintf_rewrite_tail
 393  * \sa ralloc_strcat
 394  *
 395  * \p str will be updated to the new pointer unless allocation fails.
 396  *
 397  * \return True unless allocation failed.
 398  */
 399 bool ralloc_vasprintf_append(char **str, const char *fmt, va_list args);
 400 /// @}
 401
 402 #ifdef __cplusplus
 403 } /* end of extern "C" */
 404 #endif
 405
 406 /**
 407  * Declare C++ new and delete operators which use ralloc.
 408  *
 409  * Placing this macro in the body of a class makes it possible to do:
 410  *
 411  * TYPE *var = new(mem_ctx) TYPE(...);
 412  * delete var;
 413  *
 414  * which is more idiomatic in C++ than calling ralloc.
 415  */
 416 #define DECLARE_RALLOC_CXX_OPERATORS(TYPE)                               \
 417 private:                                                                 \
 418    static void _ralloc_destructor(void *p)                               \
 419    {                                                                     \
 420       reinterpret_cast<TYPE *>(p)->~TYPE();                              \
 421    }                                                                     \
 422 public:                                                                  \
 423    static void* operator new(size_t size, void *mem_ctx)                 \
 424    {                                                                     \
 425       void *p = ralloc_size(mem_ctx, size);                              \
 426       assert(p != NULL);                                                 \
 427       if (!HAS_TRIVIAL_DESTRUCTOR(TYPE))                                 \
 428          ralloc_set_destructor(p, _ralloc_destructor);                   \
 429       return p;                                                          \
 430    }                                                                     \
 431                                                                          \
 432    static void operator delete(void *p)                                  \
 433    {                                                                     \
 434       /* The object's destructor is guaranteed to have already been      \
 435        * called by the delete operator at this point -- Make sure it's   \
 436        * not called again.                                               \
 437        */                                                                \
 438       if (!HAS_TRIVIAL_DESTRUCTOR(TYPE))                                 \
 439          ralloc_set_destructor(p, NULL);                                 \
 440       ralloc_free(p);                                                    \
 441    }
 442
 443
 444 #endif