Annotation of OpenXM_contrib/gmp/mpz/import.c, Revision 1.1
1.1 ! ohara 1: /* mpz_import -- set mpz from word data.
! 2:
! 3: Copyright 2002 Free Software Foundation, Inc.
! 4:
! 5: This file is part of the GNU MP Library.
! 6:
! 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 2.1 of the License, or (at your
! 10: option) any later version.
! 11:
! 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.
! 16:
! 17: You should have received a copy of the GNU Lesser General Public License
! 18: along with the GNU MP Library; see the file COPYING.LIB. If not, write to
! 19: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
! 20: MA 02111-1307, USA. */
! 21:
! 22: #include <stdio.h> /* for NULL */
! 23: #include "gmp.h"
! 24: #include "gmp-impl.h"
! 25:
! 26:
! 27:
! 28: #if HAVE_LIMB_BIG_ENDIAN
! 29: #define HOST_ENDIAN 1
! 30: #endif
! 31: #if HAVE_LIMB_LITTLE_ENDIAN
! 32: #define HOST_ENDIAN (-1)
! 33: #endif
! 34: #ifndef HOST_ENDIAN
! 35: static const mp_limb_t endian_test = (CNST_LIMB(1) << (GMP_LIMB_BITS-7)) - 1;
! 36: #define HOST_ENDIAN (* (signed char *) &endian_test)
! 37: #endif
! 38:
! 39:
! 40: void
! 41: mpz_import (mpz_ptr z, size_t count, int order,
! 42: size_t size, int endian, size_t nail, const void *data)
! 43: {
! 44: mp_size_t zsize;
! 45: mp_ptr zp;
! 46:
! 47: ASSERT (order == 1 || order == -1);
! 48: ASSERT (endian == 1 || endian == 0 || endian == -1);
! 49: ASSERT (nail <= 8*size);
! 50:
! 51: zsize = (count * (8*size - nail) + GMP_NUMB_BITS-1) / GMP_NUMB_BITS;
! 52: MPZ_REALLOC (z, zsize);
! 53: zp = PTR(z);
! 54:
! 55: if (endian == 0)
! 56: endian = HOST_ENDIAN;
! 57:
! 58: /* Can't use these special cases with nails currently, since they don't
! 59: mask out the nail bits in the input data. */
! 60: if (nail == 0 && GMP_NAIL_BITS == 0)
! 61: {
! 62: unsigned align = ((char *) data - (char *) NULL) % sizeof (mp_limb_t);
! 63:
! 64: if (order == -1
! 65: && size == sizeof (mp_limb_t)
! 66: && endian == HOST_ENDIAN
! 67: && align == 0)
! 68: {
! 69: MPN_COPY (zp, (mp_srcptr) data, (mp_size_t) count);
! 70: goto done;
! 71: }
! 72:
! 73: if (order == -1
! 74: && size == sizeof (mp_limb_t)
! 75: && endian == - HOST_ENDIAN
! 76: && align == 0)
! 77: {
! 78: MPN_BSWAP (zp, (mp_srcptr) data, (mp_size_t) count);
! 79: goto done;
! 80: }
! 81:
! 82: if (order == 1
! 83: && size == sizeof (mp_limb_t)
! 84: && endian == HOST_ENDIAN
! 85: && align == 0)
! 86: {
! 87: MPN_REVERSE (zp, (mp_srcptr) data, (mp_size_t) count);
! 88: goto done;
! 89: }
! 90: }
! 91:
! 92: {
! 93: mp_limb_t limb, byte, wbitsmask;
! 94: size_t i, j, numb, wbytes;
! 95: mp_size_t woffset;
! 96: unsigned char *dp;
! 97: int lbits, wbits;
! 98:
! 99: numb = size * 8 - nail;
! 100:
! 101: /* whole bytes to process */
! 102: wbytes = numb / 8;
! 103:
! 104: /* partial byte to process */
! 105: wbits = numb % 8;
! 106: wbitsmask = (CNST_LIMB(1) << wbits) - 1;
! 107:
! 108: /* offset to get to the next word after processing wbytes and wbits */
! 109: woffset = (numb + 7) / 8;
! 110: woffset = (endian >= 0 ? woffset : -woffset)
! 111: + (order < 0 ? size : - (mp_size_t) size);
! 112:
! 113: /* least significant byte */
! 114: dp = (unsigned char *) data
! 115: + (order >= 0 ? (count-1)*size : 0) + (endian >= 0 ? size-1 : 0);
! 116:
! 117: #define ACCUMULATE(N) \
! 118: do { \
! 119: ASSERT (lbits < GMP_NUMB_BITS); \
! 120: ASSERT (limb <= (CNST_LIMB(1) << lbits) - 1); \
! 121: \
! 122: limb |= (mp_limb_t) byte << lbits; \
! 123: lbits += (N); \
! 124: if (lbits >= GMP_NUMB_BITS) \
! 125: { \
! 126: *zp++ = limb & GMP_NUMB_MASK; \
! 127: lbits -= GMP_NUMB_BITS; \
! 128: ASSERT (lbits < (N)); \
! 129: limb = byte >> ((N) - lbits); \
! 130: } \
! 131: } while (0)
! 132:
! 133: limb = 0;
! 134: lbits = 0;
! 135: for (i = 0; i < count; i++)
! 136: {
! 137: for (j = 0; j < wbytes; j++)
! 138: {
! 139: byte = *dp;
! 140: dp -= endian;
! 141: ACCUMULATE (8);
! 142: }
! 143: if (wbits != 0)
! 144: {
! 145: byte = *dp & wbitsmask;
! 146: dp -= endian;
! 147: ACCUMULATE (wbits);
! 148: }
! 149: dp += woffset;
! 150: }
! 151:
! 152: if (lbits != 0)
! 153: {
! 154: ASSERT (lbits <= GMP_NUMB_BITS);
! 155: ASSERT_LIMB (limb);
! 156: *zp++ = limb;
! 157: }
! 158:
! 159: ASSERT (zp == PTR(z) + zsize);
! 160:
! 161: /* low byte of word after most significant */
! 162: ASSERT (dp == (unsigned char *) data
! 163: + (order < 0 ? count*size : - (mp_size_t) size)
! 164: + (endian >= 0 ? (mp_size_t) size - 1 : 0));
! 165:
! 166: }
! 167:
! 168: done:
! 169: zp = PTR(z);
! 170: MPN_NORMALIZE (zp, zsize);
! 171: SIZ(z) = zsize;
! 172: }
FreeBSD-CVSweb <freebsd-cvsweb@FreeBSD.org>
![[BACK]](/icons/cvsweb/back.gif){kind=icon}
Return to import.c CVS log ![[TXT]](/icons/cvsweb/text.gif){kind=icon}
![[DIR]](/icons/cvsweb/dir.gif){kind=icon}
Up to [local] / OpenXM_contrib / gmp / mpz