X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/ba6e6b64033b1f9de49feccb5c9cd438354481f7..0f00dc4c8eb47e67bc0f148c2dd109f73a451e0a:/f-niceprime.c diff --git a/f-niceprime.c b/f-niceprime.c deleted file mode 100644 index 83b9ca5..0000000 --- a/f-niceprime.c +++ /dev/null @@ -1,164 +0,0 @@ -/* -*-c-*- - * - * $Id$ - * - * Prime fields with efficient reduction for special-form primes - * - * (c) 2004 Straylight/Edgeware - */ - -/*----- Licensing notice --------------------------------------------------* - * - * This file is part of Catacomb. - * - * Catacomb is free software; you can redistribute it and/or modify - * it under the terms of the GNU Library General Public License as - * published by the Free Software Foundation; either version 2 of the - * License, or (at your option) any later version. - * - * Catacomb 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 Library General Public License for more details. - * - * You should have received a copy of the GNU Library General Public - * License along with Catacomb; if not, write to the Free - * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, - * MA 02111-1307, USA. - */ - -/*----- Header files ------------------------------------------------------*/ - -#include - -#include "field.h" -#include "field-guts.h" -#include "mprand.h" - -/*----- Main code ---------------------------------------------------------*/ - -/* --- Field operations --- */ - -static void fdestroy(field *ff) { - fctx_niceprime *f = (fctx_niceprime *)ff; - mpreduce_destroy(&f->r); - DESTROY(f); -} - -static mp *frand(field *ff, mp *d, grand *r) { - fctx_niceprime *f = (fctx_niceprime *)ff; - return (mprand_range(d, f->r.p, r, 0)); -} - -static int fzerop(field *ff, mp *x) { return (MP_ZEROP(x)); } - -static mp *fneg(field *ff, mp *d, mp *x) { - fctx_niceprime *f = (fctx_niceprime *)ff; - return (mp_sub(d, f->r.p, x)); -} - -static mp *fadd(field *ff, mp *d, mp *x, mp *y) { - fctx_niceprime *f = (fctx_niceprime *)ff; d = mp_add(d, x, y); - if (MP_NEGP(d)) d = mp_add(d, d, f->r.p); - else if (MP_CMP(d, >, f->r.p)) d = mp_sub(d, d, f->r.p); - return (d); -} - -static mp *fsub(field *ff, mp *d, mp *x, mp *y) { - fctx_niceprime *f = (fctx_niceprime *)ff; d = mp_sub(d, x, y); - if (MP_NEGP(d)) d = mp_add(d, d, f->r.p); - else if (MP_CMP(d, >, f->r.p)) d = mp_sub(d, d, f->r.p); - return (d); -} - -static mp *fmul(field *ff, mp *d, mp *x, mp *y) { - fctx_niceprime *f = (fctx_niceprime *)ff; d = mp_mul(d, x, y); - return (mpreduce_do(&f->r, d, d)); -} - -static mp *fsqr(field *ff, mp *d, mp *x) { - fctx_niceprime *f = (fctx_niceprime *)ff; d = mp_sqr(d, x); - return (mpreduce_do(&f->r, d, d)); -} - -static mp *finv(field *ff, mp *d, mp *x) { - fctx_niceprime *f = (fctx_niceprime *)ff; - d = mp_modinv(d, x, f->r.p); - return (d); -} - -static mp *freduce(field *ff, mp *d, mp *x) { - fctx_niceprime *f = (fctx_niceprime *)ff; - return (mpreduce_do(&f->r, d, x)); -} - -static mp *fsqrt(field *ff, mp *d, mp *x) { - fctx_niceprime *f = (fctx_niceprime *)ff; - return (mp_modsqrt(d, x, f->r.p)); -} - -static mp *fdbl(field *ff, mp *d, mp *x) { - fctx_niceprime *f = (fctx_niceprime *)ff; d = mp_lsl(d, x, 1); - if (MP_CMP(d, >=, f->r.p)) d = mp_sub(d, d, f->r.p); - return (d); -} - -static mp *ftpl(field *ff, mp *d, mp *x) { - fctx_niceprime *f = (fctx_niceprime *)ff; MP_DEST(d, MP_LEN(x) + 1, x->f); - MPX_UMULN(d->v, d->vl, x->v, x->vl, 3); d->f &= ~MP_UNDEF; - while (MP_CMP(d, >=, f->r.p)) d = mp_sub(d, d, f->r.p); - return (d); -} - -static mp *fqdl(field *ff, mp *d, mp *x) { - fctx_niceprime *f = (fctx_niceprime *)ff; d = mp_lsl(d, x, 2); - while (MP_CMP(d, >=, f->r.p)) d = mp_sub(d, d, f->r.p); - return (d); -} - -static mp *fhlv(field *ff, mp *d, mp *x) { - fctx_niceprime *f = (fctx_niceprime *)ff; - if (MP_ZEROP(x)) { MP_COPY(x); MP_DROP(d); return (x); } - if (x->v[0] & 1) { d = mp_add(d, x, f->r.p); x = d; } - return (mp_lsr(d, x, 1)); -} - -/* --- Field operations table --- */ - -static const field_ops fops = { - FTY_PRIME, "niceprime", - fdestroy, frand, field_stdsamep, - freduce, field_id, - fzerop, fneg, fadd, fsub, fmul, fsqr, finv, freduce, fsqrt, - 0, - fdbl, ftpl, fqdl, fhlv -}; - -/* --- @field_niceprime@ --- * - * - * Arguments: @mp *p@ = the characteristic of the field - * - * Returns: A pointer to the field, or null. - * - * Use: Creates a field structure for a prime field of size %$p$%, - * using efficient reduction for nice primes. - */ - -field *field_niceprime(mp *p) -{ - fctx_niceprime *f = CREATE(fctx_niceprime); - f->f.ops = &fops; - f->f.zero = MP_ZERO; - f->f.one = MP_ONE; - f->f.nbits = mp_bits(p); - f->f.noctets = (f->f.nbits + 7) >> 3; - if (mpreduce_create(&f->r, p)) { - DESTROY(f); - return (0); - } - f->f.m = f->r.p; - f->f.q = f->r.p; - return (&f->f); -} - -/*----- That's all, folks -------------------------------------------------*/