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fb019a0e BV |
1 | /* |
2 | * This file is part of the libsigrok project. | |
3 | * | |
4 | * Copyright (C) 2014 Bert Vermeulen <bert@biot.com> | |
5 | * | |
6 | * This program is free software: you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation, either version 3 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
18 | */ | |
19 | ||
20 | #include <string.h> | |
21 | #include "libsigrok.h" | |
22 | #include "libsigrok-internal.h" | |
23 | ||
24 | #define LOG_PREFIX "analog" | |
25 | ||
41caa319 AJ |
26 | SR_PRIV int sr_analog_init(struct sr_datafeed_analog2 *analog, |
27 | struct sr_analog_encoding *encoding, | |
28 | struct sr_analog_meaning *meaning, | |
29 | struct sr_analog_spec *spec, | |
30 | int digits) | |
31 | { | |
32 | memset(analog, 0, sizeof(*analog)); | |
33 | memset(encoding, 0, sizeof(*encoding)); | |
34 | memset(meaning, 0, sizeof(*meaning)); | |
35 | memset(spec, 0, sizeof(*spec)); | |
36 | ||
37 | analog->encoding = encoding; | |
38 | analog->meaning = meaning; | |
39 | analog->spec = spec; | |
40 | ||
41 | encoding->unitsize = sizeof(float); | |
42 | encoding->is_float = TRUE; | |
43 | #ifdef WORDS_BIGENDIAN | |
44 | encoding->is_bigendian = TRUE; | |
45 | #else | |
46 | encoding->is_bigendian = FALSE; | |
47 | #endif | |
48 | encoding->digits = digits; | |
49 | encoding->is_digits_decimal = TRUE; | |
50 | encoding->scale.p = 1; | |
51 | encoding->scale.q = 1; | |
52 | encoding->offset.p = 0; | |
53 | encoding->offset.q = 1; | |
54 | ||
55 | spec->spec_digits = digits; | |
56 | ||
57 | return SR_OK; | |
58 | } | |
59 | ||
fb019a0e BV |
60 | SR_API int sr_analog_to_float(const struct sr_datafeed_analog2 *analog, |
61 | float *buf) | |
62 | { | |
63 | float offset; | |
64 | unsigned int b, i; | |
65 | gboolean bigendian; | |
66 | ||
67 | #ifdef WORDS_BIGENDIAN | |
68 | bigendian = TRUE; | |
69 | #else | |
70 | bigendian = FALSE; | |
71 | #endif | |
72 | if (!analog->encoding->is_float) { | |
73 | /* TODO */ | |
74 | sr_err("Only floating-point analog data supported so far."); | |
75 | return SR_ERR; | |
76 | } | |
77 | ||
78 | if (analog->encoding->unitsize == sizeof(float) | |
79 | && analog->encoding->is_bigendian == bigendian | |
80 | && (analog->encoding->scale.p == analog->encoding->scale.q) | |
81 | && analog->encoding->scale.p / (float)analog->encoding->scale.q == 0) { | |
82 | /* The data is already in the right format. */ | |
83 | memcpy(buf, analog->data, analog->num_samples * sizeof(float)); | |
84 | } else { | |
85 | for (i = 0; i < analog->num_samples; i += analog->encoding->unitsize) { | |
86 | for (b = 0; b < analog->encoding->unitsize; b++) { | |
87 | if (analog->encoding->is_bigendian == bigendian) | |
88 | buf[i + b] = ((float *)analog->data)[i * analog->encoding->unitsize + b]; | |
89 | else | |
90 | buf[i + (analog->encoding->unitsize - b)] = ((float *)analog->data)[i * analog->encoding->unitsize + b]; | |
91 | } | |
92 | if (analog->encoding->scale.p != analog->encoding->scale.q) | |
93 | buf[i] = (buf[i] * analog->encoding->scale.p) / analog->encoding->scale.q; | |
94 | offset = ((float)analog->encoding->scale.p / (float)analog->encoding->scale.q); | |
95 | buf[i] += offset; | |
96 | } | |
97 | } | |
98 | ||
99 | return SR_OK; | |
100 | } |