diff options
Diffstat (limited to 'plugins/MirOTR/libgcrypt-1.4.6/mpi/mpi-add.c')
| -rw-r--r-- | plugins/MirOTR/libgcrypt-1.4.6/mpi/mpi-add.c | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/plugins/MirOTR/libgcrypt-1.4.6/mpi/mpi-add.c b/plugins/MirOTR/libgcrypt-1.4.6/mpi/mpi-add.c new file mode 100644 index 0000000000..ada257ae1e --- /dev/null +++ b/plugins/MirOTR/libgcrypt-1.4.6/mpi/mpi-add.c @@ -0,0 +1,236 @@ +/* mpi-add.c - MPI functions + * Copyright (C) 1994, 1996, 1998, 2001, 2002, 2003 Free Software Foundation, Inc. + * + * This file is part of Libgcrypt. + * + * Libgcrypt 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 2.1 of + * the License, or (at your option) any later version. + * + * Libgcrypt 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 this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA + * + * Note: This code is heavily based on the GNU MP Library. + * Actually it's the same code with only minor changes in the + * way the data is stored; this is to support the abstraction + * of an optional secure memory allocation which may be used + * to avoid revealing of sensitive data due to paging etc. + */ + +#include <config.h> +#include <stdio.h> +#include <stdlib.h> + +#include "mpi-internal.h" + + +/**************** + * Add the unsigned integer V to the mpi-integer U and store the + * result in W. U and V may be the same. + */ +void +gcry_mpi_add_ui(gcry_mpi_t w, gcry_mpi_t u, unsigned long v ) +{ + mpi_ptr_t wp, up; + mpi_size_t usize, wsize; + int usign, wsign; + + usize = u->nlimbs; + usign = u->sign; + wsign = 0; + + /* If not space for W (and possible carry), increase space. */ + wsize = usize + 1; + if( w->alloced < wsize ) + mpi_resize(w, wsize); + + /* These must be after realloc (U may be the same as W). */ + up = u->d; + wp = w->d; + + if( !usize ) { /* simple */ + wp[0] = v; + wsize = v? 1:0; + } + else if( !usign ) { /* mpi is not negative */ + mpi_limb_t cy; + cy = _gcry_mpih_add_1(wp, up, usize, v); + wp[usize] = cy; + wsize = usize + cy; + } + else { /* The signs are different. Need exact comparison to determine + * which operand to subtract from which. */ + if( usize == 1 && up[0] < v ) { + wp[0] = v - up[0]; + wsize = 1; + } + else { + _gcry_mpih_sub_1(wp, up, usize, v); + /* Size can decrease with at most one limb. */ + wsize = usize - (wp[usize-1]==0); + wsign = 1; + } + } + + w->nlimbs = wsize; + w->sign = wsign; +} + + +void +gcry_mpi_add(gcry_mpi_t w, gcry_mpi_t u, gcry_mpi_t v) +{ + mpi_ptr_t wp, up, vp; + mpi_size_t usize, vsize, wsize; + int usign, vsign, wsign; + + if( u->nlimbs < v->nlimbs ) { /* Swap U and V. */ + usize = v->nlimbs; + usign = v->sign; + vsize = u->nlimbs; + vsign = u->sign; + wsize = usize + 1; + RESIZE_IF_NEEDED(w, wsize); + /* These must be after realloc (u or v may be the same as w). */ + up = v->d; + vp = u->d; + } + else { + usize = u->nlimbs; + usign = u->sign; + vsize = v->nlimbs; + vsign = v->sign; + wsize = usize + 1; + RESIZE_IF_NEEDED(w, wsize); + /* These must be after realloc (u or v may be the same as w). */ + up = u->d; + vp = v->d; + } + wp = w->d; + wsign = 0; + + if( !vsize ) { /* simple */ + MPN_COPY(wp, up, usize ); + wsize = usize; + wsign = usign; + } + else if( usign != vsign ) { /* different sign */ + /* This test is right since USIZE >= VSIZE */ + if( usize != vsize ) { + _gcry_mpih_sub(wp, up, usize, vp, vsize); + wsize = usize; + MPN_NORMALIZE(wp, wsize); + wsign = usign; + } + else if( _gcry_mpih_cmp(up, vp, usize) < 0 ) { + _gcry_mpih_sub_n(wp, vp, up, usize); + wsize = usize; + MPN_NORMALIZE(wp, wsize); + if( !usign ) + wsign = 1; + } + else { + _gcry_mpih_sub_n(wp, up, vp, usize); + wsize = usize; + MPN_NORMALIZE(wp, wsize); + if( usign ) + wsign = 1; + } + } + else { /* U and V have same sign. Add them. */ + mpi_limb_t cy = _gcry_mpih_add(wp, up, usize, vp, vsize); + wp[usize] = cy; + wsize = usize + cy; + if( usign ) + wsign = 1; + } + + w->nlimbs = wsize; + w->sign = wsign; +} + + +/**************** + * Subtract the unsigned integer V from the mpi-integer U and store the + * result in W. + */ +void +gcry_mpi_sub_ui(gcry_mpi_t w, gcry_mpi_t u, unsigned long v ) +{ + mpi_ptr_t wp, up; + mpi_size_t usize, wsize; + int usign, wsign; + + usize = u->nlimbs; + usign = u->sign; + wsign = 0; + + /* If not space for W (and possible carry), increase space. */ + wsize = usize + 1; + if( w->alloced < wsize ) + mpi_resize(w, wsize); + + /* These must be after realloc (U may be the same as W). */ + up = u->d; + wp = w->d; + + if( !usize ) { /* simple */ + wp[0] = v; + wsize = v? 1:0; + wsign = 1; + } + else if( usign ) { /* mpi and v are negative */ + mpi_limb_t cy; + cy = _gcry_mpih_add_1(wp, up, usize, v); + wp[usize] = cy; + wsize = usize + cy; + } + else { /* The signs are different. Need exact comparison to determine + * which operand to subtract from which. */ + if( usize == 1 && up[0] < v ) { + wp[0] = v - up[0]; + wsize = 1; + wsign = 1; + } + else { + _gcry_mpih_sub_1(wp, up, usize, v); + /* Size can decrease with at most one limb. */ + wsize = usize - (wp[usize-1]==0); + } + } + + w->nlimbs = wsize; + w->sign = wsign; +} + +void +gcry_mpi_sub(gcry_mpi_t w, gcry_mpi_t u, gcry_mpi_t v) +{ + gcry_mpi_t vv = mpi_copy (v); + vv->sign = ! vv->sign; + gcry_mpi_add (w, u, vv); + mpi_free (vv); +} + + +void +gcry_mpi_addm( gcry_mpi_t w, gcry_mpi_t u, gcry_mpi_t v, gcry_mpi_t m) +{ + gcry_mpi_add(w, u, v); + _gcry_mpi_fdiv_r( w, w, m ); +} + +void +gcry_mpi_subm( gcry_mpi_t w, gcry_mpi_t u, gcry_mpi_t v, gcry_mpi_t m) +{ + gcry_mpi_sub(w, u, v); + _gcry_mpi_fdiv_r( w, w, m ); +} + |