1 /* obstack.c - subroutines used implicitly by object stack macros 2 Copyright (C) 1988-2015 Free Software Foundation, Inc. 3 This file is part of the GNU C Library. 4 5 The GNU C Library is free software; you can redistribute it and/or 6 modify it under the terms of the GNU Lesser General Public 7 License as published by the Free Software Foundation; either 8 version 2.1 of the License, or (at your option) any later version. 9 10 The GNU C Library is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 Lesser General Public License for more details. 14 15 You should have received a copy of the GNU Lesser General Public 16 License along with the GNU C Library; if not, see 17 <http://www.gnu.org/licenses/>. */ 18 19 20 #ifdef _LIBC 21 # include <obstack.h> 22 #else 23 # include <config.h> 24 # include "obstack.h" 25 #endif 26 27 /* NOTE BEFORE MODIFYING THIS FILE: _OBSTACK_INTERFACE_VERSION in 28 obstack.h must be incremented whenever callers compiled using an old 29 obstack.h can no longer properly call the functions in this file. */ 30 31 /* Comment out all this code if we are using the GNU C Library, and are not 32 actually compiling the library itself, and the installed library 33 supports the same library interface we do. This code is part of the GNU 34 C Library, but also included in many other GNU distributions. Compiling 35 and linking in this code is a waste when using the GNU C library 36 (especially if it is a shared library). Rather than having every GNU 37 program understand 'configure --with-gnu-libc' and omit the object 38 files, it is simpler to just do this in the source for each such file. */ 39 #if !defined _LIBC && defined __GNU_LIBRARY__ && __GNU_LIBRARY__ > 1 40 # include <gnu-versions.h> 41 # if (_GNU_OBSTACK_INTERFACE_VERSION == _OBSTACK_INTERFACE_VERSION \ 42 || (_GNU_OBSTACK_INTERFACE_VERSION == 1 \ 43 && _OBSTACK_INTERFACE_VERSION == 2 \ 44 && defined SIZEOF_INT && defined SIZEOF_SIZE_T \ 45 && SIZEOF_INT == SIZEOF_SIZE_T)) 46 # define _OBSTACK_ELIDE_CODE 47 # endif 48 #endif 49 50 #ifndef _OBSTACK_ELIDE_CODE 51 /* If GCC, or if an oddball (testing?) host that #defines __alignof__, 52 use the already-supplied __alignof__. Otherwise, this must be Gnulib 53 (as glibc assumes GCC); defer to Gnulib's alignof_type. */ 54 # if !defined __GNUC__ && !defined __IBM__ALIGNOF__ && !defined __alignof__ 55 # if defined __cplusplus 56 template <class type> struct alignof_helper { char __slot1; type __slot2; }; 57 # define __alignof__(type) offsetof (alignof_helper<type>, __slot2) 58 # else 59 # define __alignof__(type) \ 60 offsetof (struct { char __slot1; type __slot2; }, __slot2) 61 # endif 62 # endif 63 # include <stdlib.h> 64 # include <stdint.h> 65 66 # ifndef MAX 67 # define MAX(a,b) ((a) > (b) ? (a) : (b)) 68 # endif 69 70 /* Determine default alignment. */ 71 72 /* If malloc were really smart, it would round addresses to DEFAULT_ALIGNMENT. 73 But in fact it might be less smart and round addresses to as much as 74 DEFAULT_ROUNDING. So we prepare for it to do that. 75 76 DEFAULT_ALIGNMENT cannot be an enum constant; see gnulib's alignof.h. */ 77 #define DEFAULT_ALIGNMENT MAX (__alignof__ (long double), \ 78 MAX (__alignof__ (uintmax_t), \ 79 __alignof__ (void *))) 80 #define DEFAULT_ROUNDING MAX (sizeof (long double), \ 81 MAX (sizeof (uintmax_t), \ 82 sizeof (void *))) 83 84 /* Call functions with either the traditional malloc/free calling 85 interface, or the mmalloc/mfree interface (that adds an extra first 86 argument), based on the value of use_extra_arg. */ 87 88 static void * 89 call_chunkfun (struct obstack *h, size_t size) 90 { 91 if (h->use_extra_arg) 92 return h->chunkfun.extra (h->extra_arg, size); 93 else 94 return h->chunkfun.plain (size); 95 } 96 97 static void 98 call_freefun (struct obstack *h, void *old_chunk) 99 { 100 if (h->use_extra_arg) 101 h->freefun.extra (h->extra_arg, old_chunk); 102 else 103 h->freefun.plain (old_chunk); 104 } 105 106 107 /* Initialize an obstack H for use. Specify chunk size SIZE (0 means default). 108 Objects start on multiples of ALIGNMENT (0 means use default). 109 110 Return nonzero if successful, calls obstack_alloc_failed_handler if 111 allocation fails. */ 112 113 static int 114 _obstack_begin_worker (struct obstack *h, 115 _OBSTACK_SIZE_T size, _OBSTACK_SIZE_T alignment) 116 { 117 struct _obstack_chunk *chunk; /* points to new chunk */ 118 119 if (alignment == 0) 120 alignment = DEFAULT_ALIGNMENT; 121 if (size == 0) 122 /* Default size is what GNU malloc can fit in a 4096-byte block. */ 123 { 124 /* 12 is sizeof (mhead) and 4 is EXTRA from GNU malloc. 125 Use the values for range checking, because if range checking is off, 126 the extra bytes won't be missed terribly, but if range checking is on 127 and we used a larger request, a whole extra 4096 bytes would be 128 allocated. 129 130 These number are irrelevant to the new GNU malloc. I suspect it is 131 less sensitive to the size of the request. */ 132 int extra = ((((12 + DEFAULT_ROUNDING - 1) & ~(DEFAULT_ROUNDING - 1)) 133 + 4 + DEFAULT_ROUNDING - 1) 134 & ~(DEFAULT_ROUNDING - 1)); 135 size = 4096 - extra; 136 } 137 138 h->chunk_size = size; 139 h->alignment_mask = alignment - 1; 140 141 chunk = (struct _obstack_chunk *) call_chunkfun (h, h->chunk_size); 142 if (!chunk) 143 (*obstack_alloc_failed_handler) (); 144 h->chunk = chunk; 145 h->next_free = h->object_base = __PTR_ALIGN ((char *) chunk, chunk->contents, 146 alignment - 1); 147 h->chunk_limit = chunk->limit = (char *) chunk + h->chunk_size; 148 chunk->prev = 0; 149 /* The initial chunk now contains no empty object. */ 150 h->maybe_empty_object = 0; 151 h->alloc_failed = 0; 152 return 1; 153 } 154 155 int 156 _obstack_begin (struct obstack *h, 157 _OBSTACK_SIZE_T size, _OBSTACK_SIZE_T alignment, 158 void *(*chunkfun) (size_t), 159 void (*freefun) (void *)) 160 { 161 h->chunkfun.plain = chunkfun; 162 h->freefun.plain = freefun; 163 h->use_extra_arg = 0; 164 return _obstack_begin_worker (h, size, alignment); 165 } 166 167 int 168 _obstack_begin_1 (struct obstack *h, 169 _OBSTACK_SIZE_T size, _OBSTACK_SIZE_T alignment, 170 void *(*chunkfun) (void *, size_t), 171 void (*freefun) (void *, void *), 172 void *arg) 173 { 174 h->chunkfun.extra = chunkfun; 175 h->freefun.extra = freefun; 176 h->extra_arg = arg; 177 h->use_extra_arg = 1; 178 return _obstack_begin_worker (h, size, alignment); 179 } 180 181 /* Allocate a new current chunk for the obstack *H 182 on the assumption that LENGTH bytes need to be added 183 to the current object, or a new object of length LENGTH allocated. 184 Copies any partial object from the end of the old chunk 185 to the beginning of the new one. */ 186 187 void 188 _obstack_newchunk (struct obstack *h, _OBSTACK_SIZE_T length) 189 { 190 struct _obstack_chunk *old_chunk = h->chunk; 191 struct _obstack_chunk *new_chunk = 0; 192 size_t obj_size = h->next_free - h->object_base; 193 char *object_base; 194 195 /* Compute size for new chunk. */ 196 size_t sum1 = obj_size + length; 197 size_t sum2 = sum1 + h->alignment_mask; 198 size_t new_size = sum2 + (obj_size >> 3) + 100; 199 if (new_size < sum2) 200 new_size = sum2; 201 if (new_size < h->chunk_size) 202 new_size = h->chunk_size; 203 204 /* Allocate and initialize the new chunk. */ 205 if (obj_size <= sum1 && sum1 <= sum2) 206 new_chunk = (struct _obstack_chunk *) call_chunkfun (h, new_size); 207 if (!new_chunk) 208 (*obstack_alloc_failed_handler)(); 209 h->chunk = new_chunk; 210 new_chunk->prev = old_chunk; 211 new_chunk->limit = h->chunk_limit = (char *) new_chunk + new_size; 212 213 /* Compute an aligned object_base in the new chunk */ 214 object_base = 215 __PTR_ALIGN ((char *) new_chunk, new_chunk->contents, h->alignment_mask); 216 217 /* Move the existing object to the new chunk. */ 218 memcpy (object_base, h->object_base, obj_size); 219 220 /* If the object just copied was the only data in OLD_CHUNK, 221 free that chunk and remove it from the chain. 222 But not if that chunk might contain an empty object. */ 223 if (!h->maybe_empty_object 224 && (h->object_base 225 == __PTR_ALIGN ((char *) old_chunk, old_chunk->contents, 226 h->alignment_mask))) 227 { 228 new_chunk->prev = old_chunk->prev; 229 call_freefun (h, old_chunk); 230 } 231 232 h->object_base = object_base; 233 h->next_free = h->object_base + obj_size; 234 /* The new chunk certainly contains no empty object yet. */ 235 h->maybe_empty_object = 0; 236 } 237 238 /* Return nonzero if object OBJ has been allocated from obstack H. 239 This is here for debugging. 240 If you use it in a program, you are probably losing. */ 241 242 /* Suppress -Wmissing-prototypes warning. We don't want to declare this in 243 obstack.h because it is just for debugging. */ 244 int _obstack_allocated_p (struct obstack *h, void *obj) __attribute_pure__; 245 246 int 247 _obstack_allocated_p (struct obstack *h, void *obj) 248 { 249 struct _obstack_chunk *lp; /* below addr of any objects in this chunk */ 250 struct _obstack_chunk *plp; /* point to previous chunk if any */ 251 252 lp = (h)->chunk; 253 /* We use >= rather than > since the object cannot be exactly at 254 the beginning of the chunk but might be an empty object exactly 255 at the end of an adjacent chunk. */ 256 while (lp != 0 && ((void *) lp >= obj || (void *) (lp)->limit < obj)) 257 { 258 plp = lp->prev; 259 lp = plp; 260 } 261 return lp != 0; 262 } 263 264 /* Free objects in obstack H, including OBJ and everything allocate 265 more recently than OBJ. If OBJ is zero, free everything in H. */ 266 267 void 268 _obstack_free (struct obstack *h, void *obj) 269 { 270 struct _obstack_chunk *lp; /* below addr of any objects in this chunk */ 271 struct _obstack_chunk *plp; /* point to previous chunk if any */ 272 273 lp = h->chunk; 274 /* We use >= because there cannot be an object at the beginning of a chunk. 275 But there can be an empty object at that address 276 at the end of another chunk. */ 277 while (lp != 0 && ((void *) lp >= obj || (void *) (lp)->limit < obj)) 278 { 279 plp = lp->prev; 280 call_freefun (h, lp); 281 lp = plp; 282 /* If we switch chunks, we can't tell whether the new current 283 chunk contains an empty object, so assume that it may. */ 284 h->maybe_empty_object = 1; 285 } 286 if (lp) 287 { 288 h->object_base = h->next_free = (char *) (obj); 289 h->chunk_limit = lp->limit; 290 h->chunk = lp; 291 } 292 else if (obj != 0) 293 /* obj is not in any of the chunks! */ 294 abort (); 295 } 296 297 _OBSTACK_SIZE_T 298 _obstack_memory_used (struct obstack *h) 299 { 300 struct _obstack_chunk *lp; 301 _OBSTACK_SIZE_T nbytes = 0; 302 303 for (lp = h->chunk; lp != 0; lp = lp->prev) 304 { 305 nbytes += lp->limit - (char *) lp; 306 } 307 return nbytes; 308 } 309 310 # ifndef _OBSTACK_NO_ERROR_HANDLER 311 /* Define the error handler. */ 312 # include <stdio.h> 313 314 /* Exit value used when 'print_and_abort' is used. */ 315 # ifdef _LIBC 316 int obstack_exit_failure = EXIT_FAILURE; 317 # else 318 # ifndef EXIT_FAILURE 319 # define EXIT_FAILURE 1 320 # endif 321 # define obstack_exit_failure EXIT_FAILURE 322 # endif 323 324 # if defined _LIBC || (HAVE_LIBINTL_H && ENABLE_NLS) 325 # include <libintl.h> 326 # ifndef _ 327 # define _(msgid) gettext (msgid) 328 # endif 329 # else 330 # ifndef _ 331 # define _(msgid) (msgid) 332 # endif 333 # endif 334 335 # if !(defined _Noreturn \ 336 || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 201112)) 337 # if ((defined __GNUC__ \ 338 && (__GNUC__ >= 3 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 8))) \ 339 || (defined __SUNPRO_C && __SUNPRO_C >= 0x5110)) 340 # define _Noreturn __attribute__ ((__noreturn__)) 341 # elif defined _MSC_VER && _MSC_VER >= 1200 342 # define _Noreturn __declspec (noreturn) 343 # else 344 # define _Noreturn 345 # endif 346 # endif 347 348 # ifdef _LIBC 349 # include <libio/iolibio.h> 350 # endif 351 352 static _Noreturn void 353 print_and_abort (void) 354 { 355 /* Don't change any of these strings. Yes, it would be possible to add 356 the newline to the string and use fputs or so. But this must not 357 happen because the "memory exhausted" message appears in other places 358 like this and the translation should be reused instead of creating 359 a very similar string which requires a separate translation. */ 360 # ifdef _LIBC 361 (void) __fxprintf (NULL, "%s\n", _("memory exhausted")); 362 # else 363 fprintf (stderr, "%s\n", _("memory exhausted")); 364 # endif 365 exit (obstack_exit_failure); 366 } 367 368 /* The functions allocating more room by calling 'obstack_chunk_alloc' 369 jump to the handler pointed to by 'obstack_alloc_failed_handler'. 370 This can be set to a user defined function which should either 371 abort gracefully or use longjump - but shouldn't return. This 372 variable by default points to the internal function 373 'print_and_abort'. */ 374 void (*obstack_alloc_failed_handler) (void) = print_and_abort; 375 # endif /* !_OBSTACK_NO_ERROR_HANDLER */ 376 #endif /* !_OBSTACK_ELIDE_CODE */ 377
