Bill Yi | 4e213d5 | 2015-06-23 13:53:11 -0700 | [diff] [blame] | 1 | /* 16-bit signed integer dot product |
| 2 | * Portable C version |
| 3 | * Copyright 2004 Phil Karn |
| 4 | * May be used under the terms of the GNU Lesser General Public License (LGPL) |
| 5 | */ |
| 6 | #include <stdlib.h> |
| 7 | #include "fec.h" |
| 8 | |
| 9 | struct dotprod { |
| 10 | int len; /* Number of coefficients */ |
| 11 | |
| 12 | signed short *coeffs; |
| 13 | }; |
| 14 | |
| 15 | /* Create and return a descriptor for use with the dot product function */ |
| 16 | void *initdp_port(signed short coeffs[],int len){ |
| 17 | struct dotprod *dp; |
| 18 | int j; |
| 19 | |
| 20 | if(len == 0) |
| 21 | return NULL; |
| 22 | |
| 23 | dp = (struct dotprod *)calloc(1,sizeof(struct dotprod)); |
| 24 | dp->len = len; |
| 25 | |
| 26 | /* Just one copy of the coefficients for the C version */ |
| 27 | dp->coeffs = (signed short *)calloc(len,sizeof(signed short)); |
| 28 | for(j=0;j<len;j++) |
| 29 | dp->coeffs[j] = coeffs[j]; |
| 30 | return (void *)dp; |
| 31 | } |
| 32 | |
| 33 | |
| 34 | /* Free a dot product descriptor created earlier */ |
| 35 | void freedp_port(void *p){ |
| 36 | struct dotprod *dp = (struct dotprod *)p; |
| 37 | |
| 38 | if(dp->coeffs != NULL) |
| 39 | free(dp->coeffs); |
| 40 | free(dp); |
| 41 | } |
| 42 | |
| 43 | /* Compute a dot product given a descriptor and an input array |
| 44 | * The length is taken from the descriptor |
| 45 | */ |
| 46 | long dotprod_port(void *p,signed short a[]){ |
| 47 | struct dotprod *dp = (struct dotprod *)p; |
| 48 | long corr; |
| 49 | int i; |
| 50 | |
| 51 | corr = 0; |
| 52 | for(i=0;i<dp->len;i++){ |
| 53 | corr += (long)a[i] * dp->coeffs[i]; |
| 54 | } |
| 55 | return corr; |
| 56 | } |
| 57 | |
| 58 | |