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-rw-r--r--lib/reed_solomon/encode_rs.c54
1 files changed, 54 insertions, 0 deletions
diff --git a/lib/reed_solomon/encode_rs.c b/lib/reed_solomon/encode_rs.c
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+/*
+ * 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;
+}