src/util/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 #include <stddef.h>
  50 #include <stdarg.h>
  51 #include <stdbool.h>
  52
  53 #include "macros.h"
  54
  55 #ifdef __cplusplus
  56 extern "C" {
  57 #endif
  58
  59 /**
  60  * \def ralloc(ctx, type)
  61  * Allocate a new object chained off of the given context.
  62  *
  63  * This is equivalent to:
  64  * \code
  65  * ((type *) ralloc_size(ctx, sizeof(type))
  66  * \endcode
  67  */
  68 #define ralloc(ctx, type)  ((type *) ralloc_size(ctx, sizeof(type)))
  69
  70 /**
  71  * \def rzalloc(ctx, type)
  72  * Allocate a new object out of the given context and initialize it to zero.
  73  *
  74  * This is equivalent to:
  75  * \code
  76  * ((type *) rzalloc_size(ctx, sizeof(type))
  77  * \endcode
  78  */
  79 #define rzalloc(ctx, type) ((type *) rzalloc_size(ctx, sizeof(type)))
  80
  81 /**
  82  * Allocate a new ralloc context.
  83  *
  84  * While any ralloc'd pointer can be used as a context, sometimes it is useful
  85  * to simply allocate a context with no associated memory.
  86  *
  87  * It is equivalent to:
  88  * \code
  89  * ((type *) ralloc_size(ctx, 0)
  90  * \endcode
  91  */
  92 void *ralloc_context(const void *ctx);
  93
  94 /**
  95  * Allocate memory chained off of the given context.
  96  *
  97  * This is the core allocation routine which is used by all others.  It
  98  * simply allocates storage for \p size bytes and returns the pointer,
  99  * similar to \c malloc.
 100  */
 101 void *ralloc_size(const void *ctx, size_t size) MALLOCLIKE;
 102
 103 /**
 104  * Allocate zero-initialized memory chained off of the given context.
 105  *
 106  * This is similar to \c calloc with a size of 1.
 107  */
 108 void *rzalloc_size(const void *ctx, size_t size) MALLOCLIKE;
 109
 110 /**
 111  * Resize a piece of ralloc-managed memory, preserving data.
 112  *
 113  * Similar to \c realloc.  Unlike C89, passing 0 for \p size does not free the
 114  * memory.  Instead, it resizes it to a 0-byte ralloc context, just like
 115  * calling ralloc_size(ctx, 0).  This is different from talloc.
 116  *
 117  * \param ctx  The context to use for new allocation.  If \p ptr != NULL,
 118  *             it must be the same as ralloc_parent(\p ptr).
 119  * \param ptr  Pointer to the memory to be resized.  May be NULL.
 120  * \param size The amount of memory to allocate, in bytes.
 121  */
 122 void *reralloc_size(const void *ctx, void *ptr, size_t size);
 123
 124 /// \defgroup array Array Allocators @{
 125
 126 /**
 127  * \def ralloc_array(ctx, type, count)
 128  * Allocate an array of objects chained off the given context.
 129  *
 130  * Similar to \c calloc, but does not initialize the memory to zero.
 131  *
 132  * More than a convenience function, this also checks for integer overflow when
 133  * multiplying \c sizeof(type) and \p count.  This is necessary for security.
 134  *
 135  * This is equivalent to:
 136  * \code
 137  * ((type *) ralloc_array_size(ctx, sizeof(type), count)
 138  * \endcode
 139  */
 140 #define ralloc_array(ctx, type, count) \
 141    ((type *) ralloc_array_size(ctx, sizeof(type), count))
 142
 143 /**
 144  * \def rzalloc_array(ctx, type, count)
 145  * Allocate a zero-initialized array chained off the given context.
 146  *
 147  * Similar to \c calloc.
 148  *
 149  * More than a convenience function, this also checks for integer overflow when
 150  * multiplying \c sizeof(type) and \p count.  This is necessary for security.
 151  *
 152  * This is equivalent to:
 153  * \code
 154  * ((type *) rzalloc_array_size(ctx, sizeof(type), count)
 155  * \endcode
 156  */
 157 #define rzalloc_array(ctx, type, count) \
 158    ((type *) rzalloc_array_size(ctx, sizeof(type), count))
 159
 160 /**
 161  * \def reralloc(ctx, ptr, type, count)
 162  * Resize a ralloc-managed array, preserving data.
 163  *
 164  * Similar to \c realloc.  Unlike C89, passing 0 for \p size does not free the
 165  * memory.  Instead, it resizes it to a 0-byte ralloc context, just like
 166  * calling ralloc_size(ctx, 0).  This is different from talloc.
 167  *
 168  * More than a convenience function, this also checks for integer overflow when
 169  * multiplying \c sizeof(type) and \p count.  This is necessary for security.
 170  *
 171  * \param ctx   The context to use for new allocation.  If \p ptr != NULL,
 172  *              it must be the same as ralloc_parent(\p ptr).
 173  * \param ptr   Pointer to the array to be resized.  May be NULL.
 174  * \param type  The element type.
 175  * \param count The number of elements to allocate.
 176  */
 177 #define reralloc(ctx, ptr, type, count) \
 178    ((type *) reralloc_array_size(ctx, ptr, sizeof(type), count))
 179
 180 /**
 181  * Allocate memory for an array chained off the given context.
 182  *
 183  * Similar to \c calloc, but does not initialize the memory to zero.
 184  *
 185  * More than a convenience function, this also checks for integer overflow when
 186  * multiplying \p size and \p count.  This is necessary for security.
 187  */
 188 void *ralloc_array_size(const void *ctx, size_t size, unsigned count) MALLOCLIKE;
 189
 190 /**
 191  * Allocate a zero-initialized array chained off the given context.
 192  *
 193  * Similar to \c calloc.
 194  *
 195  * More than a convenience function, this also checks for integer overflow when
 196  * multiplying \p size and \p count.  This is necessary for security.
 197  */
 198 void *rzalloc_array_size(const void *ctx, size_t size, unsigned count) MALLOCLIKE;
 199
 200 /**
 201  * Resize a ralloc-managed array, preserving data.
 202  *
 203  * Similar to \c realloc.  Unlike C89, passing 0 for \p size does not free the
 204  * memory.  Instead, it resizes it to a 0-byte ralloc context, just like
 205  * calling ralloc_size(ctx, 0).  This is different from talloc.
 206  *
 207  * More than a convenience function, this also checks for integer overflow when
 208  * multiplying \c sizeof(type) and \p count.  This is necessary for security.
 209  *
 210  * \param ctx   The context to use for new allocation.  If \p ptr != NULL,
 211  *              it must be the same as ralloc_parent(\p ptr).
 212  * \param ptr   Pointer to the array to be resized.  May be NULL.
 213  * \param size  The size of an individual element.
 214  * \param count The number of elements to allocate.
 215  *
 216  * \return True unless allocation failed.
 217  */
 218 void *reralloc_array_size(const void *ctx, void *ptr, size_t size,
 219                           unsigned count);
 220 /// @}
 221
 222 /**
 223  * Free a piece of ralloc-managed memory.
 224  *
 225  * This will also free the memory of any children allocated this context.
 226  */
 227 void ralloc_free(void *ptr);
 228
 229 /**
 230  * "Steal" memory from one context, changing it to another.
 231  *
 232  * This changes \p ptr's context to \p new_ctx.  This is quite useful if
 233  * memory is allocated out of a temporary context.
 234  */
 235 void ralloc_steal(const void *new_ctx, void *ptr);
 236
 237 /**
 238  * Reparent all children from one context to another.
 239  *
 240  * This effectively calls ralloc_steal(new_ctx, child) for all children of \p old_ctx.
 241  */
 242 void ralloc_adopt(const void *new_ctx, void *old_ctx);
 243
 244 /**
 245  * Return the given pointer's ralloc context.
 246  */
 247 void *ralloc_parent(const void *ptr);
 248
 249 /**
 250  * Set a callback to occur just before an object is freed.
 251  */
 252 void ralloc_set_destructor(const void *ptr, void(*destructor)(void *));
 253
 254 /// \defgroup array String Functions @{
 255 /**
 256  * Duplicate a string, allocating the memory from the given context.
 257  */
 258 char *ralloc_strdup(const void *ctx, const char *str) MALLOCLIKE;
 259
 260 /**
 261  * Duplicate a string, allocating the memory from the given context.
 262  *
 263  * Like \c strndup, at most \p n characters are copied.  If \p str is longer
 264  * than \p n characters, \p n are copied, and a termining \c '\0' byte is added.
 265  */
 266 char *ralloc_strndup(const void *ctx, const char *str, size_t n) MALLOCLIKE;
 267
 268 /**
 269  * Concatenate two strings, allocating the necessary space.
 270  *
 271  * This appends \p str to \p *dest, similar to \c strcat, using ralloc_resize
 272  * to expand \p *dest to the appropriate size.  \p dest will be updated to the
 273  * new pointer unless allocation fails.
 274  *
 275  * The result will always be null-terminated.
 276  *
 277  * \return True unless allocation failed.
 278  */
 279 bool ralloc_strcat(char **dest, const char *str);
 280
 281 /**
 282  * Concatenate two strings, allocating the necessary space.
 283  *
 284  * This appends at most \p n bytes of \p str to \p *dest, using ralloc_resize
 285  * to expand \p *dest to the appropriate size.  \p dest will be updated to the
 286  * new pointer unless allocation fails.
 287  *
 288  * The result will always be null-terminated; \p str does not need to be null
 289  * terminated if it is longer than \p n.
 290  *
 291  * \return True unless allocation failed.
 292  */
 293 bool ralloc_strncat(char **dest, const char *str, size_t n);
 294
 295 /**
 296  * Concatenate two strings, allocating the necessary space.
 297  *
 298  * This appends \p n bytes of \p str to \p *dest, using ralloc_resize
 299  * to expand \p *dest to the appropriate size.  \p dest will be updated to the
 300  * new pointer unless allocation fails.
 301  *
 302  * The result will always be null-terminated.
 303  *
 304  * This function differs from ralloc_strcat() and ralloc_strncat() in that it
 305  * does not do any strlen() calls which can become costly on large strings.
 306  *
 307  * \return True unless allocation failed.
 308  */
 309 bool
 310 ralloc_str_append(char **dest, const char *str,
 311                   size_t existing_length, size_t str_size);
 312
 313 /**
 314  * Print to a string.
 315  *
 316  * This is analogous to \c sprintf, but allocates enough space (using \p ctx
 317  * as the context) for the resulting string.
 318  *
 319  * \return The newly allocated string.
 320  */
 321 char *ralloc_asprintf (const void *ctx, const char *fmt, ...) PRINTFLIKE(2, 3) MALLOCLIKE;
 322
 323 /**
 324  * Print to a string, given a va_list.
 325  *
 326  * This is analogous to \c vsprintf, but allocates enough space (using \p ctx
 327  * as the context) for the resulting string.
 328  *
 329  * \return The newly allocated string.
 330  */
 331 char *ralloc_vasprintf(const void *ctx, const char *fmt, va_list args) MALLOCLIKE;
 332
 333 /**
 334  * Rewrite the tail of an existing string, starting at a given index.
 335  *
 336  * Overwrites the contents of *str starting at \p start with newly formatted
 337  * text, including a new null-terminator.  Allocates more memory as necessary.
 338  *
 339  * This can be used to append formatted text when the length of the existing
 340  * string is already known, saving a strlen() call.
 341  *
 342  * \sa ralloc_asprintf_append
 343  *
 344  * \param str   The string to be updated.
 345  * \param start The index to start appending new data at.
 346  * \param fmt   A printf-style formatting string
 347  *
 348  * \p str will be updated to the new pointer unless allocation fails.
 349  * \p start will be increased by the length of the newly formatted text.
 350  *
 351  * \return True unless allocation failed.
 352  */
 353 bool ralloc_asprintf_rewrite_tail(char **str, size_t *start,
 354                                   const char *fmt, ...)
 355                                   PRINTFLIKE(3, 4);
 356
 357 /**
 358  * Rewrite the tail of an existing string, starting at a given index.
 359  *
 360  * Overwrites the contents of *str starting at \p start with newly formatted
 361  * text, including a new null-terminator.  Allocates more memory as necessary.
 362  *
 363  * This can be used to append formatted text when the length of the existing
 364  * string is already known, saving a strlen() call.
 365  *
 366  * \sa ralloc_vasprintf_append
 367  *
 368  * \param str   The string to be updated.
 369  * \param start The index to start appending new data at.
 370  * \param fmt   A printf-style formatting string
 371  * \param args  A va_list containing the data to be formatted
 372  *
 373  * \p str will be updated to the new pointer unless allocation fails.
 374  * \p start will be increased by the length of the newly formatted text.
 375  *
 376  * \return True unless allocation failed.
 377  */
 378 bool ralloc_vasprintf_rewrite_tail(char **str, size_t *start, const char *fmt,
 379                                    va_list args);
 380
 381 /**
 382  * Append formatted text to the supplied string.
 383  *
 384  * This is equivalent to
 385  * \code
 386  * ralloc_asprintf_rewrite_tail(str, strlen(*str), fmt, ...)
 387  * \endcode
 388  *
 389  * \sa ralloc_asprintf
 390  * \sa ralloc_asprintf_rewrite_tail
 391  * \sa ralloc_strcat
 392  *
 393  * \p str will be updated to the new pointer unless allocation fails.
 394  *
 395  * \return True unless allocation failed.
 396  */
 397 bool ralloc_asprintf_append (char **str, const char *fmt, ...)
 398                              PRINTFLIKE(2, 3);
 399
 400 /**
 401  * Append formatted text to the supplied string, given a va_list.
 402  *
 403  * This is equivalent to
 404  * \code
 405  * ralloc_vasprintf_rewrite_tail(str, strlen(*str), fmt, args)
 406  * \endcode
 407  *
 408  * \sa ralloc_vasprintf
 409  * \sa ralloc_vasprintf_rewrite_tail
 410  * \sa ralloc_strcat
 411  *
 412  * \p str will be updated to the new pointer unless allocation fails.
 413  *
 414  * \return True unless allocation failed.
 415  */
 416 bool ralloc_vasprintf_append(char **str, const char *fmt, va_list args);
 417 /// @}
 418
 419 /**
 420  * Declare C++ new and delete operators which use ralloc.
 421  *
 422  * Placing this macro in the body of a class makes it possible to do:
 423  *
 424  * TYPE *var = new(mem_ctx) TYPE(...);
 425  * delete var;
 426  *
 427  * which is more idiomatic in C++ than calling ralloc.
 428  */
 429 #define DECLARE_ALLOC_CXX_OPERATORS_TEMPLATE(TYPE, ALLOC_FUNC)           \
 430 private:                                                                 \
 431    static void _ralloc_destructor(void *p)                               \
 432    {                                                                     \
 433       reinterpret_cast<TYPE *>(p)->~TYPE();                              \
 434    }                                                                     \
 435 public:                                                                  \
 436    static void* operator new(size_t size, void *mem_ctx)                 \
 437    {                                                                     \
 438       void *p = ALLOC_FUNC(mem_ctx, size);                               \
 439       assert(p != NULL);                                                 \
 440       if (!HAS_TRIVIAL_DESTRUCTOR(TYPE))                                 \
 441          ralloc_set_destructor(p, _ralloc_destructor);                   \
 442       return p;                                                          \
 443    }                                                                     \
 444                                                                          \
 445    static void operator delete(void *p)                                  \
 446    {                                                                     \
 447       /* The object's destructor is guaranteed to have already been      \
 448        * called by the delete operator at this point -- Make sure it's   \
 449        * not called again.                                               \
 450        */                                                                \
 451       if (!HAS_TRIVIAL_DESTRUCTOR(TYPE))                                 \
 452          ralloc_set_destructor(p, NULL);                                 \
 453       ralloc_free(p);                                                    \
 454    }
 455
 456 #define DECLARE_RALLOC_CXX_OPERATORS(type) \
 457    DECLARE_ALLOC_CXX_OPERATORS_TEMPLATE(type, ralloc_size)
 458
 459 #define DECLARE_RZALLOC_CXX_OPERATORS(type) \
 460    DECLARE_ALLOC_CXX_OPERATORS_TEMPLATE(type, rzalloc_size)
 461
 462 #define DECLARE_LINEAR_ALLOC_CXX_OPERATORS(type) \
 463    DECLARE_ALLOC_CXX_OPERATORS_TEMPLATE(type, linear_alloc_child)
 464
 465 #define DECLARE_LINEAR_ZALLOC_CXX_OPERATORS(type) \
 466    DECLARE_ALLOC_CXX_OPERATORS_TEMPLATE(type, linear_zalloc_child)
 467
 468
 469 /**
 470  * Do a fast allocation from the linear buffer, also known as the child node
 471  * from the allocator's point of view. It can't be freed directly. You have
 472  * to free the parent or the ralloc parent.
 473  *
 474  * \param parent   parent node of the linear allocator
 475  * \param size     size to allocate (max 32 bits)
 476  */
 477 void *linear_alloc_child(void *parent, unsigned size);
 478
 479 /**
 480  * Allocate a parent node that will hold linear buffers. The returned
 481  * allocation is actually the first child node, but it's also the handle
 482  * of the parent node. Use it for all child node allocations.
 483  *
 484  * \param ralloc_ctx  ralloc context, must not be NULL
 485  * \param size        size to allocate (max 32 bits)
 486  */
 487 void *linear_alloc_parent(void *ralloc_ctx, unsigned size);
 488
 489 /**
 490  * Same as linear_alloc_child, but also clears memory.
 491  */
 492 void *linear_zalloc_child(void *parent, unsigned size);
 493
 494 /**
 495  * Same as linear_alloc_parent, but also clears memory.
 496  */
 497 void *linear_zalloc_parent(void *ralloc_ctx, unsigned size);
 498
 499 /**
 500  * Free the linear parent node. This will free all child nodes too.
 501  * Freeing the ralloc parent will also free this.
 502  */
 503 void linear_free_parent(void *ptr);
 504
 505 /**
 506  * Same as ralloc_steal, but steals the linear parent node.
 507  */
 508 void ralloc_steal_linear_parent(void *new_ralloc_ctx, void *ptr);
 509
 510 /**
 511  * Return the ralloc parent of the linear parent node.
 512  */
 513 void *ralloc_parent_of_linear_parent(void *ptr);
 514
 515 /**
 516  * Same as realloc except that the linear allocator doesn't free child nodes,
 517  * so it's reduced to memory duplication. It's used in places where
 518  * reallocation is required. Don't use it often. It's much slower than
 519  * realloc.
 520  */
 521 void *linear_realloc(void *parent, void *old, unsigned new_size);
 522
 523 /* The functions below have the same semantics as their ralloc counterparts,
 524  * except that they always allocate a linear child node.
 525  */
 526 char *linear_strdup(void *parent, const char *str);
 527 char *linear_asprintf(void *parent, const char *fmt, ...);
 528 char *linear_vasprintf(void *parent, const char *fmt, va_list args);
 529 bool linear_asprintf_append(void *parent, char **str, const char *fmt, ...);
 530 bool linear_vasprintf_append(void *parent, char **str, const char *fmt,
 531                              va_list args);
 532 bool linear_asprintf_rewrite_tail(void *parent, char **str, size_t *start,
 533                                   const char *fmt, ...);
 534 bool linear_vasprintf_rewrite_tail(void *parent, char **str, size_t *start,
 535                                    const char *fmt, va_list args);
 536 bool linear_strcat(void *parent, char **dest, const char *str);
 537
 538 #ifdef __cplusplus
 539 } /* end of extern "C" */
 540 #endif
 541
 542 #endif