mirror of
https://github.com/jerryscript-project/jerryscript.git
synced 2025-12-15 16:29:21 +00:00
105 lines
3.4 KiB
C
105 lines
3.4 KiB
C
/* Copyright 2015-2016 Samsung Electronics Co., Ltd.
|
|
* Copyright 2015-2016 University of Szeged
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
#include "rcs-cpointer.h"
|
|
#include "jrt-bit-fields.h"
|
|
|
|
/**
|
|
* Compress pointer to extended compressed pointer.
|
|
*
|
|
* @return dynamic storage-specific extended compressed pointer
|
|
*/
|
|
rcs_cpointer_t
|
|
rcs_cpointer_compress (rcs_record_t *pointer) /**< pointer to compress */
|
|
{
|
|
rcs_cpointer_t cpointer;
|
|
cpointer.u.packed_value = 0;
|
|
|
|
uintptr_t base_pointer = JERRY_ALIGNDOWN ((uintptr_t) pointer, MEM_ALIGNMENT);
|
|
|
|
if ((void *) base_pointer == NULL)
|
|
{
|
|
cpointer.u.value.base_cp = MEM_CP_NULL;
|
|
}
|
|
else
|
|
{
|
|
cpointer.u.value.base_cp = mem_compress_pointer ((void *) base_pointer) & MEM_CP_MASK;
|
|
}
|
|
|
|
#if MEM_ALIGNMENT_LOG > RCS_DYN_STORAGE_LENGTH_UNIT_LOG
|
|
/*
|
|
* If alignment of a unit in recordset storage is less than required by MEM_ALIGNMENT_LOG,
|
|
* then mem_cpointer_t can't store pointer to the unit, and so, rcs_cpointer_t stores
|
|
* mem_cpointer_t to block, aligned to MEM_ALIGNMENT, and also extension with difference
|
|
* between positions of the MEM_ALIGNMENT-aligned block and the unit.
|
|
*/
|
|
uintptr_t diff = (uintptr_t) pointer - base_pointer;
|
|
|
|
JERRY_ASSERT (diff < MEM_ALIGNMENT);
|
|
JERRY_ASSERT (JRT_EXTRACT_BIT_FIELD (uintptr_t, diff, 0, RCS_DYN_STORAGE_LENGTH_UNIT_LOG) == 0);
|
|
|
|
uintptr_t ext_part = (uintptr_t) JRT_EXTRACT_BIT_FIELD (uintptr_t, diff,
|
|
RCS_DYN_STORAGE_LENGTH_UNIT_LOG,
|
|
MEM_ALIGNMENT_LOG - RCS_DYN_STORAGE_LENGTH_UNIT_LOG);
|
|
|
|
cpointer.u.value.ext = ext_part & ((1ull << (MEM_ALIGNMENT_LOG - RCS_DYN_STORAGE_LENGTH_UNIT_LOG)) - 1);
|
|
#endif /* MEM_ALIGNMENT > RCS_DYN_STORAGE_LENGTH_UNIT_LOG */
|
|
JERRY_ASSERT (rcs_cpointer_decompress (cpointer) == pointer);
|
|
|
|
return cpointer;
|
|
} /* rcs_cpointer_compress */
|
|
|
|
/**
|
|
* Decompress extended compressed pointer.
|
|
*
|
|
* @return decompressed pointer
|
|
*/
|
|
rcs_record_t *
|
|
rcs_cpointer_decompress (rcs_cpointer_t compressed_pointer) /**< recordset-specific compressed pointer */
|
|
{
|
|
uint8_t *base_pointer = NULL;
|
|
|
|
if (compressed_pointer.u.value.base_cp != MEM_CP_NULL)
|
|
{
|
|
base_pointer = (uint8_t *) mem_decompress_pointer (compressed_pointer.u.value.base_cp);
|
|
}
|
|
|
|
uintptr_t diff = 0;
|
|
#if MEM_ALIGNMENT_LOG > RCS_DYN_STORAGE_LENGTH_UNIT_LOG
|
|
/*
|
|
* See also:
|
|
* rcs_cpointer_compress
|
|
*/
|
|
|
|
diff = (uintptr_t) compressed_pointer.u.value.ext << RCS_DYN_STORAGE_LENGTH_UNIT_LOG;
|
|
#endif /* MEM_ALIGNMENT_LOG > RCS_DYN_STORAGE_LENGTH_UNIT_LOG */
|
|
rcs_record_t *rec_p = (rcs_record_t *) (base_pointer + diff);
|
|
|
|
return rec_p;
|
|
} /* rcs_cpointer_decompress */
|
|
|
|
/**
|
|
* Create NULL compressed pointer.
|
|
*
|
|
* @return NULL compressed pointer
|
|
*/
|
|
rcs_cpointer_t rcs_cpointer_null_cp (void)
|
|
{
|
|
rcs_cpointer_t cp;
|
|
cp.u.packed_value = MEM_CP_NULL;
|
|
return cp;
|
|
} /* rcs_cpointer_null_cp */
|