diff options
author | Mauro Carvalho Chehab <mchehab@redhat.com> | 2012-03-23 08:06:43 -0300 |
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committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2012-03-23 08:06:43 -0300 |
commit | 7483d45f0aee3afc0646d185cabd4af9f6cab58c (patch) | |
tree | a312f7d77c34748bec62f0431df33007b10e4e7f /lib/mpi/mpi-mpow.c | |
parent | 3e85fc1b9fc1c7e20b9a01f2314bb633bb10501a (diff) | |
parent | f92c97c8bd77992ff8bd6ef29a23dc82dca799cb (diff) |
Merge branch 'staging/for_v3.4' into v4l_for_linus
* staging/for_v3.4: (10117 commits)
[media] update CARDLIST.em28xx
[media] partially reverts changeset fa5527c
[media] stb0899: fix the limits for signal strength values
[media] em28xx: support for 2304:0242 PCTV QuatroStick (510e)
[media] em28xx: support for 2013:0251 PCTV QuatroStick nano (520e)
[media] -EINVAL -> -ENOTTY
[media] gspca - sn9c20x: Cleanup source
[media] gspca - sn9c20x: Simplify register write for capture start/stop
[media] gspca - sn9c20x: Add automatic JPEG compression mechanism
[media] gspca - sn9c20x: Greater delay in case of sensor no response
[media] gspca - sn9c20x: Optimize the code of write sequences
[media] gspca - sn9c20x: Add the JPEG compression quality control
[media] gspca - sn9c20x: Add a delay after Omnivision sensor reset
[media] gspca - sn9c20x: Propagate USB errors to higher level
[media] gspca - sn9c20x: Use the new video control mechanism
[media] gspca - sn9c20x: Fix loss of frame start
[media] gspca - zc3xx: Lack of register 08 value for sensor cs2102k
[media] gspca - ov534_9: Add brightness to OmniVision 5621 sensor
[media] gspca - zc3xx: Add V4L2_CID_JPEG_COMPRESSION_QUALITY control support
[media] pvrusb2: fix 7MHz & 8MHz DVB-T tuner support for HVR1900 rev D1F5
...
Diffstat (limited to 'lib/mpi/mpi-mpow.c')
-rw-r--r-- | lib/mpi/mpi-mpow.c | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/lib/mpi/mpi-mpow.c b/lib/mpi/mpi-mpow.c new file mode 100644 index 000000000000..7328d0d6c748 --- /dev/null +++ b/lib/mpi/mpi-mpow.c @@ -0,0 +1,134 @@ +/* mpi-mpow.c - MPI functions + * Copyright (C) 1998, 1999, 2000 Free Software Foundation, Inc. + * + * This file is part of GnuPG. + * + * GnuPG is free software; you can redistribute it and/or modify + * it under the terms of 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. + * + * GnuPG 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 a copy of the GNU 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 + */ + +#include "mpi-internal.h" +#include "longlong.h" + +static int build_index(const MPI *exparray, int k, int i, int t) +{ + int j, bitno; + int index = 0; + + bitno = t - i; + for (j = k - 1; j >= 0; j--) { + index <<= 1; + if (mpi_test_bit(exparray[j], bitno)) + index |= 1; + } + return index; +} + +/**************** + * RES = (BASE[0] ^ EXP[0]) * (BASE[1] ^ EXP[1]) * ... * mod M + */ +int mpi_mulpowm(MPI res, MPI *basearray, MPI *exparray, MPI m) +{ + int rc = -ENOMEM; + int k; /* number of elements */ + int t; /* bit size of largest exponent */ + int i, j, idx; + MPI *G = NULL; /* table with precomputed values of size 2^k */ + MPI tmp = NULL; + + for (k = 0; basearray[k]; k++) + ; + if (!k) { + pr_emerg("mpi_mulpowm: assert(k) failed\n"); + BUG(); + } + for (t = 0, i = 0; (tmp = exparray[i]); i++) { + j = mpi_get_nbits(tmp); + if (j > t) + t = j; + } + if (i != k) { + pr_emerg("mpi_mulpowm: assert(i==k) failed\n"); + BUG(); + } + if (!t) { + pr_emerg("mpi_mulpowm: assert(t) failed\n"); + BUG(); + } + if (k >= 10) { + pr_emerg("mpi_mulpowm: assert(k<10) failed\n"); + BUG(); + } + + G = kzalloc((1 << k) * sizeof *G, GFP_KERNEL); + if (!G) + goto err_out; + + /* and calculate */ + tmp = mpi_alloc(mpi_get_nlimbs(m) + 1); + if (!tmp) + goto nomem; + if (mpi_set_ui(res, 1) < 0) + goto nomem; + for (i = 1; i <= t; i++) { + if (mpi_mulm(tmp, res, res, m) < 0) + goto nomem; + idx = build_index(exparray, k, i, t); + if (!(idx >= 0 && idx < (1 << k))) { + pr_emerg("mpi_mulpowm: assert(idx >= 0 && idx < (1<<k)) failed\n"); + BUG(); + } + if (!G[idx]) { + if (!idx) { + G[0] = mpi_alloc_set_ui(1); + if (!G[0]) + goto nomem; + } else { + for (j = 0; j < k; j++) { + if ((idx & (1 << j))) { + if (!G[idx]) { + if (mpi_copy + (&G[idx], + basearray[j]) < 0) + goto nomem; + } else { + if (mpi_mulm + (G[idx], G[idx], + basearray[j], + m) < 0) + goto nomem; + } + } + } + if (!G[idx]) { + G[idx] = mpi_alloc(0); + if (!G[idx]) + goto nomem; + } + } + } + if (mpi_mulm(res, tmp, G[idx], m) < 0) + goto nomem; + } + + rc = 0; +nomem: + /* cleanup */ + mpi_free(tmp); + for (i = 0; i < (1 << k); i++) + mpi_free(G[i]); + kfree(G); +err_out: + return rc; +} |