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/* mpz_export -- create word data from mpz.
Copyright 2002, 2003, 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 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> /* for NULL */
#include "gmp-impl.h"
#include "longlong.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_export (void *data, size_t *countp, int order,
size_t size, int endian, size_t nail, mpz_srcptr z)
{
mp_size_t zsize;
mp_srcptr zp;
size_t count, dummy;
unsigned long numb;
unsigned align;
ASSERT (order == 1 || order == -1);
ASSERT (endian == 1 || endian == 0 || endian == -1);
ASSERT (nail <= 8*size);
ASSERT (nail < 8*size || SIZ(z) == 0); /* nail < 8*size+(SIZ(z)==0) */
if (countp == NULL)
countp = &dummy;
zsize = SIZ(z);
if (zsize == 0)
{
*countp = 0;
return data;
}
zsize = ABS (zsize);
zp = PTR(z);
numb = 8*size - nail;
MPN_SIZEINBASE_2EXP (count, zp, zsize, numb);
*countp = count;
if (data == NULL)
data = (*__gmp_allocate_func) (count*size);
if (endian == 0)
endian = HOST_ENDIAN;
align = ((char *) data - (char *) NULL) % sizeof (mp_limb_t);
if (nail == GMP_NAIL_BITS)
{
if (size == sizeof (mp_limb_t) && align == 0)
{
if (order == -1 && endian == HOST_ENDIAN)
{
MPN_COPY ((mp_ptr) data, zp, (mp_size_t) count);
return data;
}
if (order == 1 && endian == HOST_ENDIAN)
{
MPN_REVERSE ((mp_ptr) data, zp, (mp_size_t) count);
return data;
}
if (order == -1 && endian == -HOST_ENDIAN)
{
MPN_BSWAP ((mp_ptr) data, zp, (mp_size_t) count);
return data;
}
if (order == 1 && endian == -HOST_ENDIAN)
{
MPN_BSWAP_REVERSE ((mp_ptr) data, zp, (mp_size_t) count);
return data;
}
}
}
{
mp_limb_t limb, wbitsmask;
size_t i, numb;
mp_size_t j, wbytes, woffset;
unsigned char *dp;
int lbits, wbits;
mp_srcptr zend;
numb = size * 8 - nail;
/* whole bytes per word */
wbytes = numb / 8;
/* possible partial byte */
wbits = numb % 8;
wbitsmask = (CNST_LIMB(1) << wbits) - 1;
/* offset to get to the next word */
woffset = (endian >= 0 ? size : - (mp_size_t) size)
+ (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 EXTRACT(N, MASK) \
do { \
if (lbits >= (N)) \
{ \
*dp = limb MASK; \
limb >>= (N); \
lbits -= (N); \
} \
else \
{ \
mp_limb_t newlimb; \
newlimb = (zp == zend ? 0 : *zp++); \
*dp = (limb | (newlimb << lbits)) MASK; \
limb = newlimb >> ((N)-lbits); \
lbits += GMP_NUMB_BITS - (N); \
} \
} while (0)
zend = zp + zsize;
lbits = 0;
limb = 0;
for (i = 0; i < count; i++)
{
for (j = 0; j < wbytes; j++)
{
EXTRACT (8, + 0);
dp -= endian;
}
if (wbits != 0)
{
EXTRACT (wbits, & wbitsmask);
dp -= endian;
j++;
}
for ( ; j < size; j++)
{
*dp = '\0';
dp -= endian;
}
dp += woffset;
}
ASSERT (zp == PTR(z) + ABSIZ(z));
/* 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));
}
return data;
}
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