diff options
Diffstat (limited to 'lib/reed_solomon/encode_rs.c')
-rw-r--r-- | lib/reed_solomon/encode_rs.c | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/lib/reed_solomon/encode_rs.c b/lib/reed_solomon/encode_rs.c new file mode 100644 index 00000000..0b5b1a67 --- /dev/null +++ b/lib/reed_solomon/encode_rs.c @@ -0,0 +1,54 @@ +/* + * lib/reed_solomon/encode_rs.c + * + * Overview: + * 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) + * + * $Id: encode_rs.c,v 1.5 2005/11/07 11:14:59 gleixner Exp $ + * + */ + +/* Generic data width independent code which is included by the + * wrappers. + * int encode_rsX (struct rs_control *rs, uintX_t *data, int len, uintY_t *par) + */ +{ + 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; +} |