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Diffstat (limited to 'gnu/lib/libgmp/stack-alloc.c')
-rw-r--r-- | gnu/lib/libgmp/stack-alloc.c | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/gnu/lib/libgmp/stack-alloc.c b/gnu/lib/libgmp/stack-alloc.c new file mode 100644 index 0000000..d9619f6 --- /dev/null +++ b/gnu/lib/libgmp/stack-alloc.c @@ -0,0 +1,108 @@ +/* Stack allocation routines. This is intended for machines without support + for the `alloca' function. + +Copyright (C) 1996 Free Software Foundation, Inc. + +This file is part of the GNU MP Library. + +The GNU MP Library is free software; you can redistribute it and/or modify +it under the terms of the GNU Library General Public License as published by +the Free Software Foundation; either version 2 of the License, or (at your +option) any later version. + +The GNU MP Library is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY +or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public +License for more details. + +You should have received a copy of the GNU Library General Public License +along with the GNU MP Library; see the file COPYING.LIB. If not, write to +the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, +MA 02111-1307, USA. */ + +#include "stack-alloc.h" + +typedef struct tmp_stack tmp_stack; + +void *malloc (); +static unsigned long max_total_allocation = 0; +static unsigned long current_total_allocation = 0; + +static tmp_stack xxx = {&xxx, &xxx, 0}; +static tmp_stack *current = &xxx; + +/* Allocate a block of exactly <size> bytes. This should only be called + through the TMP_ALLOC macro, which takes care of rounding/alignment. */ +void * +__tmp_alloc (size) + unsigned long size; +{ + void *this; + + if (size > (char *) current->end - (char *) current->alloc_point) + { + void *chunk; + tmp_stack *header; + unsigned long chunk_size; + unsigned long now; + + /* Allocate a chunk that makes the total current allocation somewhat + larger than the maximum allocation ever. If size is very large, we + allocate that much. */ + + now = current_total_allocation + size; + if (now > max_total_allocation) + { + /* We need more temporary memory than ever before. Increase + for future needs. */ + now = now * 3 / 2; + chunk_size = now - current_total_allocation + sizeof (tmp_stack); + current_total_allocation = now; + max_total_allocation = current_total_allocation; + } + else + { + chunk_size = max_total_allocation - current_total_allocation + sizeof (tmp_stack); + current_total_allocation = max_total_allocation; + } + + chunk = malloc (chunk_size); + header = chunk; + header->end = (char *) chunk + chunk_size; + header->alloc_point = (char *) chunk + sizeof (tmp_stack); + header->prev = current; + current = header; + } + + this = current->alloc_point; + current->alloc_point = (char *) this + size; + return this; +} + +/* Typically called at function entry. <mark> is assigned so that __tmp_free + can later be used to reclaim all subsecuently allocated storage. */ +void +__tmp_mark (mark) + tmp_marker *mark; +{ + mark->which_chunk = current; + mark->alloc_point = current->alloc_point; +} + +/* Free everything allocated since <mark> was assigned by __tmp_mark */ +void +__tmp_free (mark) + tmp_marker *mark; +{ + while (mark->which_chunk != current) + { + tmp_stack *tmp; + + tmp = current; + current = tmp->prev; + current_total_allocation -= (((char *) (tmp->end) - (char *) tmp) + - sizeof (tmp_stack)); + free (tmp); + } + current->alloc_point = mark->alloc_point; +} |