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TASTE
uPython-mirror
Commits
fbaa1479
Commit
fbaa1479
authored
Mar 05, 2014
by
mux
Browse files
Fix gc_realloc to expand in place
* Issue #322
parent
86227ce7
Changes
1
Hide whitespace changes
Inline
Side-by-side
py/gc.c
View file @
fbaa1479
...
...
@@ -326,20 +326,72 @@ machine_uint_t gc_nbytes(void *ptr_in) {
return
0
;
}
void
*
gc_realloc
(
void
*
ptr
,
machine_uint_t
n_bytes
)
{
machine_uint_t
n_existing
=
gc_nbytes
(
ptr
);
if
(
n_bytes
<=
n_existing
)
{
return
ptr
;
}
else
{
// TODO check if we can grow inplace
void
*
ptr2
=
gc_alloc
(
n_bytes
);
if
(
ptr2
==
NULL
)
{
return
ptr2
;
void
*
gc_realloc
(
void
*
ptr_in
,
machine_uint_t
n_bytes
)
{
void
*
ptr_out
=
NULL
;
machine_uint_t
block
=
0
;
machine_uint_t
ptr
=
(
machine_uint_t
)
ptr_in
;
if
(
ptr_in
==
NULL
)
{
return
gc_alloc
(
n_bytes
);
}
if
(
VERIFY_PTR
(
ptr
)
/* verify pointer */
&&
(
block
=
BLOCK_FROM_PTR
(
ptr
))
/* get first block */
&&
ATB_GET_KIND
(
block
)
==
AT_HEAD
)
{
/* make sure it's a HEAD block */
byte
block_type
;
machine_uint_t
n_free
=
0
;
machine_uint_t
n_blocks
=
1
;
/* counting HEAD block */
/* get the number of consecutive tail blocks and
the number of free blocks after last tail block */
do
{
block_type
=
ATB_GET_KIND
(
block
+
n_blocks
+
n_free
);
switch
(
block_type
)
{
case
AT_FREE
:
n_free
++
;
break
;
case
AT_TAIL
:
n_blocks
++
;
break
;
default:
break
;
}
/* stop as soon as we find enough blocks for n_bytes */
}
while
(
block_type
!=
AT_HEAD
&&
(
n_bytes
>
(
n_blocks
*
BYTES_PER_BLOCK
)));
/* number of allocated bytes */
machine_uint_t
n_existing
=
n_blocks
*
BYTES_PER_BLOCK
;
/* check if realloc'ing to a smaller size */
if
(
n_bytes
<=
n_existing
)
{
ptr_out
=
ptr_in
;
/* TODO should free remaining tail blocks ? */
machine_uint_t
last_block
=
block
+
n_blocks
;
while
(
ATB_GET_KIND
(
last_block
)
==
AT_TAIL
)
{
ATB_ANY_TO_FREE
(
last_block
);
last_block
++
;
}
/* check if we can expand in place */
}
else
if
(
n_bytes
<=
(
n_existing
+
(
n_free
*
BYTES_PER_BLOCK
)))
{
/* number of blocks needed to expand +1 if there's a remainder */
machine_uint_t
n_diff
=
(
n_bytes
-
n_existing
)
/
BYTES_PER_BLOCK
+
((
n_bytes
-
n_existing
)
%
BYTES_PER_BLOCK
!=
0
);
DEBUG_printf
(
"gc_realloc: expanding "
UINT_FMT
" blocks ("
UINT_FMT
" bytes) to "
UINT_FMT
" blocks ("
UINT_FMT
" bytes)
\n
"
,
n_existing
/
BYTES_PER_BLOCK
,
n_existing
,
n_existing
/
BYTES_PER_BLOCK
+
n_diff
,
n_existing
+
n_diff
*
BYTES_PER_BLOCK
);
/* mark rest of blocks as used tail */
for
(
machine_uint_t
bl
=
block
+
n_blocks
;
bl
<
(
block
+
n_blocks
+
n_diff
);
bl
++
)
{
ATB_FREE_TO_TAIL
(
bl
);
}
ptr_out
=
ptr_in
;
/* try to find a new contiguous chain */
}
else
if
((
ptr_out
=
gc_alloc
(
n_bytes
))
!=
NULL
)
{
printf
(
"gc_realloc: allocated new block
\n
"
);
memcpy
(
ptr_out
,
ptr_in
,
n_existing
);
gc_free
(
ptr_in
);
}
memcpy
(
ptr2
,
ptr
,
n_existing
);
gc_free
(
ptr
);
return
ptr2
;
}
return
ptr_out
;
}
void
gc_dump_info
()
{
...
...
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