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/* mpz_import -- set mpz from word data.
Copyright 2002, 2012 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 Lesser General Public License as published by
the Free Software Foundation; either version 3 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 Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */
#include <stdio.h>
#include "gmp.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 = (count * (8*size - nail) + GMP_NUMB_BITS-1) / GMP_NUMB_BITS;
zp = MPZ_REALLOC (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)
{
unsigned align = ((char *) data - (char *) NULL) % sizeof (mp_limb_t);
if (order == -1
&& size == sizeof (mp_limb_t)
&& endian == HOST_ENDIAN
&& align == 0)
{
MPN_COPY (zp, (mp_srcptr) data, (mp_size_t) count);
goto done;
}
if (order == -1
&& size == sizeof (mp_limb_t)
&& endian == - HOST_ENDIAN
&& align == 0)
{
MPN_BSWAP (zp, (mp_srcptr) data, (mp_size_t) count);
goto done;
}
if (order == 1
&& size == sizeof (mp_limb_t)
&& endian == HOST_ENDIAN
&& align == 0)
{
MPN_REVERSE (zp, (mp_srcptr) data, (mp_size_t) count);
goto done;
}
}
{
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));
}
done:
zp = PTR(z);
MPN_NORMALIZE (zp, zsize);
SIZ(z) = zsize;
}
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