/* mpz_import -- set mpz from word data.
Copyright 2002, 2012, 2021, 2022 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 either:
* the GNU Lesser General Public License as published by the Free
Software Foundation; either version 3 of the License, or (at your
option) any later version.
or
* the GNU General Public License as published by the Free Software
Foundation; either version 2 of the License, or (at your option) any
later version.
or both in parallel, as here.
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 General Public License
for more details.
You should have received copies of the GNU General Public License and the
GNU Lesser General Public License along with the GNU MP Library. If not,
see https://www.gnu.org/licenses/. */
#include <stdio.h>
#include "gmp-impl.h"
#if HAVE_LIMB_BIG_ENDIAN
#define HOST_ENDIAN 1
#endif
#if HAVE_LIMB_LITTLE_ENDIAN
#define HOST_ENDIAN (-1)
#endif
#ifndef HOST_ENDIAN
static const mp_limb_t endian_test = (CNST_LIMB(1) << (GMP_LIMB_BITS-7)) - 1;
#define HOST_ENDIAN (* (
signed char *) &endian_test)
#endif
void
mpz_import (mpz_ptr z, size_t count,
int order,
size_t size,
int endian, size_t nail,
const void *data)
{
mp_size_t zsize;
mp_ptr zp;
ASSERT (order == 1 || order == -1);
ASSERT (endian == 1 || endian == 0 || endian == -1);
ASSERT (nail <= 8*size);
zsize = BITS_TO_LIMBS (count * (8*size - nail));
zp = MPZ_NEWALLOC (z, zsize);
if (endian == 0)
endian = HOST_ENDIAN;
/* Can't use these special cases with nails currently, since they don't
mask out the nail bits in the input data. */
if (nail == 0 && GMP_NAIL_BITS == 0
&& size ==
sizeof (mp_limb_t)
&& (((
char *) data - (
char *) NULL) %
sizeof (mp_limb_t)) == 0
/* align */)
{
if (order == -1)
{
if (endian == HOST_ENDIAN)
MPN_COPY (zp, (mp_srcptr) data, (mp_size_t) count);
else /* if (endian == - HOST_ENDIAN) */
MPN_BSWAP (zp, (mp_srcptr) data, (mp_size_t) count);
}
else /* if (order == 1) */
{
if (endian == HOST_ENDIAN)
MPN_REVERSE (zp, (mp_srcptr) data, (mp_size_t) count);
else /* if (endian == - HOST_ENDIAN) */
MPN_BSWAP_REVERSE (zp, (mp_srcptr) data, (mp_size_t) count);
}
}
else
{
mp_limb_t limb, byte, wbitsmask;
size_t i, j, numb, wbytes;
mp_size_t woffset;
unsigned char *dp;
int lbits, wbits;
numb = size * 8 - nail;
/* whole bytes to process */
wbytes = numb / 8;
/* partial byte to process */
wbits = numb % 8;
wbitsmask = (CNST_LIMB(1) << wbits) - 1;
/* offset to get to the next word after processing wbytes and wbits */
woffset = (numb + 7) / 8;
woffset = (endian >= 0 ? woffset : -woffset)
+ (order < 0 ? size : - (mp_size_t) size);
/* least significant byte */
dp = (
unsigned char *) data
+ (order >= 0 ? (count-1)*size : 0) + (endian >= 0 ? size-1 : 0);
#define ACCUMULATE(N) \
do { \
ASSERT (lbits < GMP_NUMB_BITS); \
ASSERT (limb <= (CNST_LIMB(1) << lbits) - 1); \
\
limb |= (mp_limb_t) byte << lbits; \
lbits += (N); \
if (lbits >= GMP_NUMB_BITS) \
{ \
*zp++ = limb & GMP_NUMB_MASK; \
lbits -= GMP_NUMB_BITS; \
ASSERT (lbits < (N)); \
limb = byte >> ((N) - lbits); \
} \
}
while (0)
limb = 0;
lbits = 0;
for (i = 0; i < count; i++)
{
for (j = 0; j < wbytes; j++)
{
byte = *dp;
dp -= endian;
ACCUMULATE (8);
}
if (wbits != 0)
{
byte = *dp & wbitsmask;
dp -= endian;
ACCUMULATE (wbits);
}
dp += woffset;
}
if (lbits != 0)
{
ASSERT (lbits <= GMP_NUMB_BITS);
ASSERT_LIMB (limb);
*zp++ = limb;
}
ASSERT (zp == PTR(z) + zsize);
/* low byte of word after most significant */
ASSERT (dp == (
unsigned char *) data
+ (order < 0 ? count*size : - (mp_size_t) size)
+ (endian >= 0 ? (mp_size_t) size - 1 : 0));
}
zp = PTR(z);
MPN_NORMALIZE (zp, zsize);
SIZ(z) = zsize;
}
