IEEE 802.15.4 subsystem
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Source at commit ea23c905d32bfd2478915021476f9ede2ee014b8 created 6 years 6 months ago. By Josef Filzmaier, atusb/fw: Introduction of a new board named HULUSB | |
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1 | #include <stdlib.h> |
2 | #include <stdio.h> |
3 | #include <unistd.h> |
4 | #include <math.h> |
5 | #include <sys/types.h> |
6 | |
7 | |
8 | #define PERC_DEFAULT 0.9 |
9 | |
10 | |
11 | static int comp(const void *_a, const void *_b) |
12 | { |
13 | float a = *(const float *) _a; |
14 | float b = *(const float *) _b; |
15 | |
16 | return a < b ? -1 : a > b; |
17 | } |
18 | |
19 | |
20 | static void find_peak(int skip, float percentile, int dump) |
21 | { |
22 | float max = 0; |
23 | float c[2], a; |
24 | float *rec = NULL; |
25 | int e = 0, n = 0; |
26 | |
27 | while (1) { |
28 | size_t s; |
29 | |
30 | s = fread(c, sizeof(c), 1, stdin); |
31 | if (!s) { |
32 | if (!ferror(stdin)) |
33 | break; |
34 | if (s < 0) { |
35 | perror("read"); |
36 | exit(1); |
37 | } |
38 | } |
39 | if (skip) { |
40 | skip--; |
41 | continue; |
42 | } |
43 | a = hypotf(c[0], c[1]); |
44 | if (a > max) |
45 | max = a; |
46 | if (e <= n) { |
47 | e = e ? e*2 : 10000; |
48 | rec = realloc(rec, e*sizeof(float)); |
49 | if (!rec) { |
50 | perror("realloc"); |
51 | exit(1); |
52 | } |
53 | } |
54 | rec[n] = a; |
55 | n++; |
56 | } |
57 | |
58 | if (skip >= n) { |
59 | fprintf(stderr, "cannot skip %d of %d entries\n", skip, n); |
60 | exit(1); |
61 | } |
62 | rec += skip; |
63 | n -= skip; |
64 | |
65 | qsort(rec, n, sizeof(float), comp); |
66 | |
67 | if (!dump) |
68 | printf("%f %f\n", max, rec[(int) (percentile*n)]); |
69 | else { |
70 | int i; |
71 | |
72 | for (i = 0; i < n; i += 1000) |
73 | printf("%f %f\n", (double) i/n, rec[i]); |
74 | } |
75 | } |
76 | |
77 | |
78 | static void usage(const char *name) |
79 | { |
80 | fprintf(stderr, |
81 | "usage: %s [-s skip] [percentile]\n" |
82 | " %s [-s skip] -d\n\n" |
83 | " percentile select the specified percentile (default: %g)\n\n" |
84 | " -d dump the histogram\n" |
85 | " -s skip skip this number of samples from the beginning (default: 0)\n" |
86 | , name, name, PERC_DEFAULT); |
87 | exit(1); |
88 | } |
89 | |
90 | |
91 | int main(int argc, char **argv) |
92 | { |
93 | int dump = 0, skip = 0; |
94 | float perc = PERC_DEFAULT; |
95 | int c; |
96 | |
97 | while ((c = getopt(argc, argv, "ds:")) != EOF) |
98 | switch (c) { |
99 | case 'd': |
100 | dump = 1; |
101 | break; |
102 | case 's': |
103 | skip = atoi(optarg); |
104 | break; |
105 | default: |
106 | usage(*argv); |
107 | } |
108 | |
109 | switch (argc-optind) { |
110 | case 0: |
111 | break; |
112 | case 1: |
113 | if (dump) |
114 | usage(*argv); |
115 | perc = atof(argv[optind]); |
116 | break; |
117 | default: |
118 | usage(*argv); |
119 | } |
120 | |
121 | find_peak(skip, perc, dump); |
122 | |
123 | return 0; |
124 | } |
125 |