src/glsl/ralloc.c

   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 #include <assert.h>
  25 #include <stdlib.h>
  26 #include <stdarg.h>
  27 #include <stdio.h>
  28 #include <string.h>
  29 #include <stdint.h>
  30
  31 #include "ralloc.h"
  32
  33 #ifdef __GNUC__
  34 #define likely(x)       __builtin_expect(!!(x),1)
  35 #define unlikely(x)     __builtin_expect(!!(x),0)
  36 #else
  37 #define likely(x)       !!(x)
  38 #define unlikely(x)     !!(x)
  39 #endif
  40
  41 #define CANARY 0x5A1106
  42
  43 struct ralloc_header
  44 {
  45    /* A canary value used to determine whether a pointer is ralloc'd. */
  46    unsigned canary;
  47
  48    struct ralloc_header *parent;
  49
  50    /* The first child (head of a linked list) */
  51    struct ralloc_header *child;
  52
  53    /* Linked list of siblings */
  54    struct ralloc_header *prev;
  55    struct ralloc_header *next;
  56
  57    void (*destructor)(void *);
  58 };
  59
  60 typedef struct ralloc_header ralloc_header;
  61
  62 static void unlink_block(ralloc_header *info);
  63 static void unsafe_free(ralloc_header *info);
  64
  65 static ralloc_header *
  66 get_header(const void *ptr)
  67 {
  68    ralloc_header *info = (ralloc_header *) (((char *) ptr) -
  69                                             sizeof(ralloc_header));
  70    assert(info->canary == CANARY);
  71    return info;
  72 }
  73
  74 #define PTR_FROM_HEADER(info) (((char *) info) + sizeof(ralloc_header))
  75
  76 static void
  77 add_child(ralloc_header *parent, ralloc_header *info)
  78 {
  79    if (parent != NULL) {
  80       info->parent = parent;
  81       info->next = parent->child;
  82       parent->child = info;
  83
  84       if (info->next != NULL)
  85          info->next->prev = info;
  86    }
  87 }
  88
  89 void *
  90 ralloc_context(const void *ctx)
  91 {
  92    return ralloc_size(ctx, 0);
  93 }
  94
  95 void *
  96 ralloc_size(const void *ctx, size_t size)
  97 {
  98    void *block = calloc(1, size + sizeof(ralloc_header));
  99
 100    ralloc_header *info = (ralloc_header *) block;
 101    ralloc_header *parent = ctx != NULL ? get_header(ctx) : NULL;
 102
 103    add_child(parent, info);
 104
 105    info->canary = CANARY;
 106
 107    return PTR_FROM_HEADER(info);
 108 }
 109
 110 void *
 111 rzalloc_size(const void *ctx, size_t size)
 112 {
 113    void *ptr = ralloc_size(ctx, size);
 114    if (likely(ptr != NULL))
 115       memset(ptr, 0, size);
 116    return ptr;
 117 }
 118
 119 /* helper function - assumes ptr != NULL */
 120 static void *
 121 resize(void *ptr, size_t size)
 122 {
 123    ralloc_header *child, *old, *info;
 124
 125    old = get_header(ptr);
 126    info = realloc(old, size + sizeof(ralloc_header));
 127
 128    if (info == NULL)
 129       return NULL;
 130
 131    /* Update parent and sibling's links to the reallocated node. */
 132    if (info != old && info->parent != NULL) {
 133       if (info->parent->child == old)
 134          info->parent->child = info;
 135
 136       if (info->prev != NULL)
 137          info->prev->next = info;
 138
 139       if (info->next != NULL)
 140          info->next->prev = info;
 141    }
 142
 143    /* Update child->parent links for all children */
 144    for (child = info->child; child != NULL; child = child->next)
 145       child->parent = info;
 146
 147    return PTR_FROM_HEADER(info);
 148 }
 149
 150 void *
 151 reralloc_size(const void *ctx, void *ptr, size_t size)
 152 {
 153    if (unlikely(ptr == NULL))
 154       return ralloc_size(ctx, size);
 155
 156    assert(ralloc_parent(ptr) == ctx);
 157    return resize(ptr, size);
 158 }
 159
 160 void *
 161 ralloc_array_size(const void *ctx, size_t size, unsigned count)
 162 {
 163    if (count > SIZE_MAX/size)
 164       return NULL;
 165
 166    return ralloc_size(ctx, size * count);
 167 }
 168
 169 void *
 170 rzalloc_array_size(const void *ctx, size_t size, unsigned count)
 171 {
 172    if (count > SIZE_MAX/size)
 173       return NULL;
 174
 175    return rzalloc_size(ctx, size * count);
 176 }
 177
 178 void *
 179 reralloc_array_size(const void *ctx, void *ptr, size_t size, unsigned count)
 180 {
 181    if (count > SIZE_MAX/size)
 182       return NULL;
 183
 184    return reralloc_size(ctx, ptr, size * count);
 185 }
 186
 187 void
 188 ralloc_free(void *ptr)
 189 {
 190    ralloc_header *info;
 191
 192    if (ptr == NULL)
 193       return;
 194
 195    info = get_header(ptr);
 196    unlink_block(info);
 197    unsafe_free(info);
 198 }
 199
 200 static void
 201 unlink_block(ralloc_header *info)
 202 {
 203    /* Unlink from parent & siblings */
 204    if (info->parent != NULL) {
 205       if (info->parent->child == info)
 206          info->parent->child = info->next;
 207
 208       if (info->prev != NULL)
 209          info->prev->next = info->next;
 210
 211       if (info->next != NULL)
 212          info->next->prev = info->prev;
 213    }
 214    info->parent = NULL;
 215    info->prev = NULL;
 216    info->next = NULL;
 217 }
 218
 219 static void
 220 unsafe_free(ralloc_header *info)
 221 {
 222    /* Recursively free any children...don't waste time unlinking them. */
 223    ralloc_header *temp;
 224    while (info->child != NULL) {
 225       temp = info->child;
 226       info->child = temp->next;
 227       unsafe_free(temp);
 228    }
 229
 230    /* Free the block itself.  Call the destructor first, if any. */
 231    if (info->destructor != NULL)
 232       info->destructor(PTR_FROM_HEADER(info));
 233
 234    free(info);
 235 }
 236
 237 void
 238 ralloc_steal(const void *new_ctx, void *ptr)
 239 {
 240    ralloc_header *info, *parent;
 241
 242    if (unlikely(ptr == NULL))
 243       return;
 244
 245    info = get_header(ptr);
 246    parent = get_header(new_ctx);
 247
 248    unlink_block(info);
 249
 250    add_child(parent, info);
 251 }
 252
 253 void *
 254 ralloc_parent(const void *ptr)
 255 {
 256    ralloc_header *info;
 257
 258    if (unlikely(ptr == NULL))
 259       return NULL;
 260
 261    info = get_header(ptr);
 262    return PTR_FROM_HEADER(info->parent);
 263 }
 264
 265 static void *autofree_context = NULL;
 266
 267 static void
 268 autofree(void)
 269 {
 270    ralloc_free(autofree_context);
 271 }
 272
 273 void *
 274 ralloc_autofree_context(void)
 275 {
 276    if (unlikely(autofree_context == NULL)) {
 277       autofree_context = ralloc_context(NULL);
 278       atexit(autofree);
 279    }
 280    return autofree_context;
 281 }
 282
 283 void
 284 ralloc_set_destructor(const void *ptr, void(*destructor)(void *))
 285 {
 286    ralloc_header *info = get_header(ptr);
 287    info->destructor = destructor;
 288 }
 289
 290 char *
 291 ralloc_strdup(const void *ctx, const char *str)
 292 {
 293    size_t n;
 294    char *ptr;
 295
 296    if (unlikely(str == NULL))
 297       return NULL;
 298
 299    n = strlen(str);
 300    ptr = ralloc_array(ctx, char, n + 1);
 301    memcpy(ptr, str, n);
 302    ptr[n] = '\0';
 303    return ptr;
 304 }
 305
 306 char *
 307 ralloc_strndup(const void *ctx, const char *str, size_t max)
 308 {
 309    size_t n;
 310    char *ptr;
 311
 312    if (unlikely(str == NULL))
 313       return NULL;
 314
 315    n = strlen(str);
 316    if (n > max)
 317       n = max;
 318
 319    ptr = ralloc_array(ctx, char, n + 1);
 320    memcpy(ptr, str, n);
 321    ptr[n] = '\0';
 322    return ptr;
 323 }
 324
 325 /* helper routine for strcat/strncat - n is the exact amount to copy */
 326 static bool
 327 cat(char **dest, const char *str, size_t n)
 328 {
 329    char *both;
 330    size_t existing_length;
 331    assert(dest != NULL && *dest != NULL);
 332
 333    existing_length = strlen(*dest);
 334    both = resize(*dest, existing_length + n + 1);
 335    if (unlikely(both == NULL))
 336       return false;
 337
 338    memcpy(both + existing_length, str, n);
 339    both[existing_length + n] = '\0';
 340
 341    *dest = both;
 342    return true;
 343 }
 344
 345
 346 bool
 347 ralloc_strcat(char **dest, const char *str)
 348 {
 349    return cat(dest, str, strlen(str));
 350 }
 351
 352 bool
 353 ralloc_strncat(char **dest, const char *str, size_t n)
 354 {
 355    /* Clamp n to the string length */
 356    size_t str_length = strlen(str);
 357    if (str_length < n)
 358       n = str_length;
 359
 360    return cat(dest, str, n);
 361 }
 362
 363 char *
 364 ralloc_asprintf(const void *ctx, const char *fmt, ...)
 365 {
 366    char *ptr;
 367    va_list args;
 368    va_start(args, fmt);
 369    ptr = ralloc_vasprintf(ctx, fmt, args);
 370    va_end(args);
 371    return ptr;
 372 }
 373
 374 /* Return the length of the string that would be generated by a printf-style
 375  * format and argument list, not including the \0 byte.
 376  */
 377 static size_t
 378 printf_length(const char *fmt, va_list untouched_args)
 379 {
 380    int size;
 381    char junk;
 382
 383    /* Make a copy of the va_list so the original caller can still use it */
 384    va_list args;
 385    va_copy(args, untouched_args);
 386
 387    size = vsnprintf(&junk, 1, fmt, args);
 388    assert(size >= 0);
 389
 390    return size;
 391 }
 392
 393 char *
 394 ralloc_vasprintf(const void *ctx, const char *fmt, va_list args)
 395 {
 396    size_t size = printf_length(fmt, args) + 1;
 397
 398    char *ptr = ralloc_size(ctx, size);
 399    if (ptr != NULL)
 400       vsnprintf(ptr, size, fmt, args);
 401
 402    return ptr;
 403 }
 404
 405 bool
 406 ralloc_asprintf_append(char **str, const char *fmt, ...)
 407 {
 408    bool success;
 409    va_list args;
 410    va_start(args, fmt);
 411    success = ralloc_vasprintf_append(str, fmt, args);
 412    va_end(args);
 413    return success;
 414 }
 415
 416 bool
 417 ralloc_vasprintf_append(char **str, const char *fmt, va_list args)
 418 {
 419    size_t existing_length, new_length;
 420    char *ptr;
 421
 422    assert(str != NULL);
 423
 424    if (unlikely(*str == NULL)) {
 425       // Assuming a NULL context is probably bad, but it's expected behavior.
 426       *str = ralloc_vasprintf(NULL, fmt, args);
 427       return true;
 428    }
 429
 430    existing_length = strlen(*str);
 431    new_length = printf_length(fmt, args);
 432
 433    ptr = resize(*str, existing_length + new_length + 1);
 434    if (unlikely(ptr == NULL))
 435       return false;
 436
 437    vsnprintf(ptr + existing_length, new_length + 1, fmt, args);
 438    *str = ptr;
 439    return true;
 440 }