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/*
* Library: ldlibcrc
* Author: Lammert Bies, Bastian Molkenthin, Ulf Samuelsson
*
* This file is licensed under the MIT License as stated below
*
* Copyright (c) 2016 Lammert Bies
* Copyright (c) 2013 Ulf Samuelsson (ulf@emagii.com)
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
*/
#include "sysdep.h"
#include "bfd.h"
#include "lddigest.h"
#include "ldreflect.h"
#define SHIFT(t) ((sizeof(t)-1)*8)
/* ============ CRC-32 LIBCRC functions ======================================*/
/*
* void _init_crc32_tab (uint32_t *crc_tab, uint32_t poly);
*
* For optimal speed, the CRC32 calculation uses a table with pre-calculated
* bit patterns which are used in the XOR operations in the program.
* _init_crc32_tab is copyright (c) 2016 Lammert Bies
*/
static void
_init_crc32_tab (uint32_t * crc_tab, uint32_t poly)
{
uint32_t crc;
uint32_t shift = SHIFT (uint32_t);
for (uint32_t i = 0; i < 256; i++)
{
crc = i << shift;
for (uint32_t j = 0; j < 8; j++)
{
if ((crc & 0x80000000u) != 0)
{
crc = (crc << 1) ^ poly;
}
else
{
crc = crc << 1;
}
}
crc_tab[i] = crc;
}
} /* _init_crc32__tab */
/*
* void _init_crc32_reciprocal_tab (uint32_t *crc_tab, uint32_t poly);
*
* For optimal speed, the CRC32 calculation uses a table with pre-calculated
* bit patterns which are used in the XOR operations in the program.
* _init_crc32_reciprocal_tab is copyright (c) 2021 Bastian Molkenthin
*/
static void
_init_crc32_reciprocal_tab (uint32_t * crc_tab, uint32_t poly)
{
uint32_t crc;
uint32_t reflected_poly = reflect32 (poly);
for (uint32_t i = 0; i < 256; i++)
{
crc = i;
for (uint32_t j = 0; j < 8; j++)
{
if (crc & 0x00000001U)
{
crc >>= 1;
crc ^= reflected_poly;
}
else
{
crc = crc >> 1;
}
}
crc_tab[i] = crc;
}
} /* _init_crc32_reciprocal_tab */
/*
* void init_crc32_tab( void );
*
* For optimal speed, the CRC32 calculation uses a table with pre-calculated
* bit patterns which are used in the XOR operations in the program.
* The table can be calculated in a normal or a reciprocal version.
* init_crc64_tab is copyright (c) 2023 Ulf Samuelsson
*/
uint32_t *
init_crc32_tab (algorithm_desc_t * dsc)
{
uint32_t *crc_tab = malloc (256 * sizeof (uint32_t));
if (crc_tab == NULL)
return NULL;
if (dsc->reciprocal)
{
_init_crc32_reciprocal_tab (crc_tab, dsc->poly.d32._0);
}
else
{
_init_crc32_tab (crc_tab, dsc->poly.d32._0);
}
return crc_tab;
} /* init_crc32_tab */
/*
* uint32_t calc_crc32(algorithm_desc_t *dsc, const unsigned char *input_str, size_t num_bytes);
*
* The function calc_crc32() calculates in one pass the common 32 bit CRC value for
* a byte string that is passed to the function together with a parameter
* indicating the length.
* calc_crc32 is
* copyright (c) 2016 Lammert Bies
* copyright (c) 2021 Bastian Molkenthin
* copyright (c) 2023 Ulf Samuelsson
*/
uint32_t
calc_crc32 (algorithm_desc_t * dsc, const unsigned char *input_str,
size_t num_bytes)
{
uint32_t crc;
const unsigned char *ptr;
uint32_t index;
uint32_t *crc_tab = dsc->crc_tab;
if ((ptr = input_str) == NULL)
return 0;
if (crc_tab == NULL)
return 0;
crc = dsc->initial.d32._0;
if (dsc->reciprocal)
{
for (uint32_t i = 0; i < num_bytes; i++)
{
index = ((crc >> 0) ^ (uint32_t) * ptr++) & 0x000000FFul;
crc = (crc >> 8) ^ crc_tab[index];
}
}
else
{
uint32_t shift = SHIFT (uint32_t);
for (uint32_t i = 0; i < num_bytes; i++)
{
const unsigned char c = *ptr++;
uint32_t rc = (uint32_t) (dsc->ireflect ? reflect8 (c) : c);
crc = (crc ^ (rc << shift));
index = (uint32_t) (crc >> shift);
crc = (crc << 8);
crc = (crc ^ (crc_tab[index]));
}
}
crc = (dsc->oreflect ? reflect32 (crc) : crc);
crc = crc ^ dsc->xor_val.d32._0;
return crc;
} /* calc_crc32 */
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