diff options
Diffstat (limited to '')
| -rw-r--r-- | lib/reed_solomon/encode_rs.c | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/lib/reed_solomon/encode_rs.c b/lib/reed_solomon/encode_rs.c new file mode 100644 index 0000000000..9112d46e86 --- /dev/null +++ b/lib/reed_solomon/encode_rs.c @@ -0,0 +1,47 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Generic Reed Solomon encoder / decoder library + * + * Copyright 2002, Phil Karn, KA9Q + * May be used under the terms of the GNU General Public License (GPL) + * + * Adaption to the kernel by Thomas Gleixner (tglx@linutronix.de) + * + * Generic data width independent code which is included by the wrappers. + */ +{ + struct rs_codec *rs = rsc->codec; + int i, j, pad; + int nn = rs->nn; + int nroots = rs->nroots; + uint16_t *alpha_to = rs->alpha_to; + uint16_t *index_of = rs->index_of; + uint16_t *genpoly = rs->genpoly; + uint16_t fb; + uint16_t msk = (uint16_t) rs->nn; + + /* Check length parameter for validity */ + pad = nn - nroots - len; + if (pad < 0 || pad >= nn) + return -ERANGE; + + for (i = 0; i < len; i++) { + fb = index_of[((((uint16_t) data[i])^invmsk) & msk) ^ par[0]]; + /* feedback term is non-zero */ + if (fb != nn) { + for (j = 1; j < nroots; j++) { + par[j] ^= alpha_to[rs_modnn(rs, fb + + genpoly[nroots - j])]; + } + } + /* Shift */ + memmove(&par[0], &par[1], sizeof(uint16_t) * (nroots - 1)); + if (fb != nn) { + par[nroots - 1] = alpha_to[rs_modnn(rs, + fb + genpoly[0])]; + } else { + par[nroots - 1] = 0; + } + } + return 0; +} |