glibc/extensions/obstack.h

64 The way we do this is to take a large chunk, allocating memory from
65 low addresses.  When you want to build a symbol in the chunk you just
66 add chars above the current "high water mark" in the chunk.  When you
69 Mostly the chars will not burst over the highest address of the chunk,
70 because you would typically expect a chunk to be (say) 100 times as
80 When the chars burst over a chunk boundary, we allocate a larger
81 chunk, and then copy the partly formed object from the end of the old
82 chunk to the beginning of the new larger chunk.  We then carry on
91 	We carve out one object at a time from the current chunk.
158 struct _obstack_chunk		/* Lives at front of each chunk. */
160   char  *limit;			/* 1 past end of this chunk */
161   struct _obstack_chunk *prev;	/* address of prior chunk or NULL */
165 struct obstack		/* control current object in current chunk */
168   struct _obstack_chunk *chunk;	/* address of current struct obstack_chunk */
171   char	*chunk_limit;		/* address of char after current chunk */
180   void *extra_arg;		/* first arg for chunk alloc/dealloc funcs */
182   struct _obstack_chunk *(*chunkfun) (); /* User's fcn to allocate a chunk.  */
183   void (*freefun) ();		/* User's function to free a chunk.  */
184   char *extra_arg;		/* first arg for chunk alloc/dealloc funcs */
186   unsigned use_extra_arg:1;	/* chunk alloc/dealloc funcs take extra arg */
188 				   chunk contains a zero-length object.  This
189 				   prevents freeing the chunk if we allocate
190 				   a bigger chunk to replace it. */
277    because a new chunk might be needed to hold the final size.  */
285 /* Pointer to next byte not yet allocated in current chunk.  */
394      (__o->chunk->prev == 0 && __o->next_free - __o->chunk->contents == 0); })
490    if (__o1->next_free - (char *)__o1->chunk				\
491        > __o1->chunk_limit - (char *)__o1->chunk)			\
500    if (__obj > (void *)__o->chunk && __obj < (void *)__o->chunk_limit)  \
514  ((h)->chunk->prev == 0 && (h)->next_free - (h)->chunk->contents == 0)
586   (((h)->next_free - (char *) (h)->chunk				\
587     > (h)->chunk_limit - (char *) (h)->chunk)				\
594 ( (h)->temp = (char *) (obj) - (char *) (h)->chunk,			\
595   (((h)->temp > 0 && (h)->temp < (h)->chunk_limit - (char *) (h)->chunk)\
597 	    = (h)->temp + (char *) (h)->chunk)				\
598    : (((obstack_free) ((h), (h)->temp + (char *) (h)->chunk), 0), 0)))
601 ( (h)->temp = (char *) (obj) - (char *) (h)->chunk,			\
602   (((h)->temp > 0 && (h)->temp < (h)->chunk_limit - (char *) (h)->chunk)\
604 	    = (h)->temp + (char *) (h)->chunk)				\
605    : (_obstack_free ((h), (h)->temp + (char *) (h)->chunk), 0)))