1 /* mpz_export -- create word data from mpz.
3 Copyright 2002, 2003 Free Software Foundation, Inc.
5 This file is part of the GNU MP Library.
7 The GNU MP Library is free software; you can redistribute it and/or modify
8 it under the terms of the GNU Lesser General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or (at your
10 option) any later version.
12 The GNU MP Library is distributed in the hope that it will be useful, but
13 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
15 License for more details.
17 You should have received a copy of the GNU Lesser General Public License
18 along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */
20 #include <stdio.h> /* for NULL */
26 #if HAVE_LIMB_BIG_ENDIAN
29 #if HAVE_LIMB_LITTLE_ENDIAN
30 #define HOST_ENDIAN (-1)
33 static const mp_limb_t endian_test = (CNST_LIMB(1) << (GMP_LIMB_BITS-7)) - 1;
34 #define HOST_ENDIAN (* (signed char *) &endian_test)
38 #define MPN_SIZEINBASE_2EXP(result, ptr, size, base2exp) \
41 unsigned long __totbits; \
42 ASSERT ((size) > 0); \
43 ASSERT ((ptr)[(size)-1] != 0); \
44 count_leading_zeros (__cnt, (ptr)[(size)-1]); \
45 __totbits = (size) * GMP_NUMB_BITS - (__cnt - GMP_NAIL_BITS); \
46 (result) = (__totbits + (base2exp)-1) / (base2exp); \
51 mpz_export (void *data, size_t *countp, int order,
52 size_t size, int endian, size_t nail, mpz_srcptr z)
60 ASSERT (order == 1 || order == -1);
61 ASSERT (endian == 1 || endian == 0 || endian == -1);
62 ASSERT (nail <= 8*size);
63 ASSERT (8*size-nail > 0);
78 MPN_SIZEINBASE_2EXP (count, zp, zsize, numb);
82 data = (*__gmp_allocate_func) (count*size);
87 align = ((char *) data - (char *) NULL) % sizeof (mp_limb_t);
89 if (nail == GMP_NAIL_BITS)
91 if (size == sizeof (mp_limb_t) && align == 0)
93 if (order == -1 && endian == HOST_ENDIAN)
95 MPN_COPY ((mp_ptr) data, zp, (mp_size_t) count);
98 if (order == 1 && endian == HOST_ENDIAN)
100 MPN_REVERSE ((mp_ptr) data, zp, (mp_size_t) count);
104 if (order == -1 && endian == -HOST_ENDIAN)
106 MPN_BSWAP ((mp_ptr) data, zp, (mp_size_t) count);
109 if (order == 1 && endian == -HOST_ENDIAN)
111 MPN_BSWAP_REVERSE ((mp_ptr) data, zp, (mp_size_t) count);
118 mp_limb_t limb, wbitsmask;
120 mp_size_t j, wbytes, woffset;
125 numb = size * 8 - nail;
127 /* whole bytes per word */
130 /* possible partial byte */
132 wbitsmask = (CNST_LIMB(1) << wbits) - 1;
134 /* offset to get to the next word */
135 woffset = (endian >= 0 ? size : - (mp_size_t) size)
136 + (order < 0 ? size : - (mp_size_t) size);
138 /* least significant byte */
139 dp = (unsigned char *) data
140 + (order >= 0 ? (count-1)*size : 0) + (endian >= 0 ? size-1 : 0);
142 #define EXTRACT(N, MASK) \
153 newlimb = (zp == zend ? 0 : *zp++); \
154 *dp = (limb | (newlimb << lbits)) MASK; \
155 limb = newlimb >> ((N)-lbits); \
156 lbits += GMP_NUMB_BITS - (N); \
163 for (i = 0; i < count; i++)
165 for (j = 0; j < wbytes; j++)
172 EXTRACT (wbits, & wbitsmask);
176 for ( ; j < size; j++)
184 ASSERT (zp == PTR(z) + ABSIZ(z));
186 /* low byte of word after most significant */
187 ASSERT (dp == (unsigned char *) data
188 + (order < 0 ? count*size : - (mp_size_t) size)
189 + (endian >= 0 ? (mp_size_t) size - 1 : 0));