]> sigrok.org Git - libsigrok.git/blame - src/scale/kern.c
kern-scale: properly set encoding digits
[libsigrok.git] / src / scale / kern.c
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1/*
2 * This file is part of the libsigrok project.
3 *
4 * Copyright (C) 2015 Uwe Hermann <uwe@hermann-uwe.de>
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 2 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, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21/*
22 * KERN scale protocol parser.
23 */
24
6ec6c43b 25#include <config.h>
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26#include <string.h>
27#include <ctype.h>
28#include <math.h>
29#include <glib.h>
30#include <libsigrok/libsigrok.h>
31#include "libsigrok-internal.h"
32
33#define LOG_PREFIX "kern"
34
35static int get_buflen(const uint8_t *buf)
36{
37 /* Find out whether it's a 14-byte or 15-byte packet. */
38 if (buf[12] == '\r' && buf[13] == '\n')
39 return 14;
40 else if (buf[13] == '\r' && buf[14] == '\n')
41 return 15;
42 else
43 return -1;
44}
45
46static int parse_value(const uint8_t *buf, float *result,
0b820550 47 int *digits, const struct kern_info *info)
e5d953b5 48{
0b820550 49 char *strval, *ptrdot;
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50 float floatval;
51 int s2, len;
52
53 s2 = (info->buflen == 14) ? 11 : 12;
54 len = (info->buflen == 14) ? 8 : 9;
55
56 if (buf[s2] == 'E') {
57 /* Display: "o-Err" or "u-Err", but protocol only has 'E'. */
58 sr_spew("Over/under limit.");
59 *result = INFINITY;
60 return SR_OK;
61 }
62
63 strval = g_strndup((const char *)buf, len);
64 floatval = g_ascii_strtod(strval, NULL);
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65 ptrdot = strchr(strval, '.');
66 if (ptrdot)
67 *digits = len - (ptrdot - strval + 1);
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68 g_free(strval);
69 *result = floatval;
70
71 return SR_OK;
72}
73
74static void parse_flags(const uint8_t *buf, struct kern_info *info)
75{
76 int u1, u2, s2;
77
78 u1 = (info->buflen == 14) ? 8 : 9;
79 u2 = (info->buflen == 14) ? 9 : 10;
80 s2 = (info->buflen == 14) ? 11 : 12;
81
82 /* Bytes U1, U2: Unit */
83 info->is_gram = (buf[u1] == ' ' && buf[u2] == 'G');
84 info->is_carat = (buf[u1] == 'C' && buf[u2] == 'T');
85 info->is_ounce = (buf[u1] == 'O' && buf[u2] == 'Z');
86 info->is_pound = (buf[u1] == 'L' && buf[u2] == 'B');
87 info->is_troy_ounce = (buf[u1] == 'O' && buf[u2] == 'T');
88 info->is_pennyweight = (buf[u1] == 'D' && buf[u2] == 'W');
89 info->is_grain = (buf[u1] == 'G' && buf[u2] == 'R');
90 info->is_tael = (buf[u1] == 'T' && buf[u2] == 'L');
91 info->is_momme = (buf[u1] == 'M' && buf[u2] == 'O');
92 info->is_tola = (buf[u1] == 't' && buf[u2] == 'o');
93 info->is_percentage = (buf[u1] == ' ' && buf[u2] == '%');
94 info->is_piece = (buf[u1] == 'P' && buf[u2] == 'C');
95
96 /*
97 * Note: The display can show 3 different variants for Tael:
98 * "Hong Kong", "Singapore, Malaysia", and "Taiwan". However,
99 * in the protocol only one Tael value ('T', 'L') is used, thus
100 * we cannot distinguish between them.
101 */
102
103 /* Byte S1: Result / data type (currently unused) */
104
105 /* Byte S2: Status of the data */
106 info->is_unstable = (buf[s2] == 'U');
107 info->is_stable = (buf[s2] == 'S');
108 info->is_error = (buf[s2] == 'E');
109 /* Space: no special status. */
110
111 /* Byte CR: Always '\r' (carriage return, 0x0d, 13) */
112
113 /* Byte LF: Always '\n' (newline, 0x0a, 10) */
114}
115
c6d52747 116static void handle_flags(struct sr_datafeed_analog *analog, float *floatval,
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117 const struct kern_info *info)
118{
119 (void)floatval;
120
121 /* Measured quantity: mass. */
c6d52747 122 analog->meaning->mq = SR_MQ_MASS;
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123
124 /* Unit */
125 if (info->is_gram)
c6d52747 126 analog->meaning->unit = SR_UNIT_GRAM;
e5d953b5 127 if (info->is_carat)
c6d52747 128 analog->meaning->unit = SR_UNIT_CARAT;
e5d953b5 129 if (info->is_ounce)
c6d52747 130 analog->meaning->unit = SR_UNIT_OUNCE;
e5d953b5 131 if (info->is_pound)
c6d52747 132 analog->meaning->unit = SR_UNIT_POUND;
e5d953b5 133 if (info->is_troy_ounce)
c6d52747 134 analog->meaning->unit = SR_UNIT_TROY_OUNCE;
e5d953b5 135 if (info->is_pennyweight)
c6d52747 136 analog->meaning->unit = SR_UNIT_PENNYWEIGHT;
e5d953b5 137 if (info->is_grain)
c6d52747 138 analog->meaning->unit = SR_UNIT_GRAIN;
e5d953b5 139 if (info->is_tael)
c6d52747 140 analog->meaning->unit = SR_UNIT_TAEL;
e5d953b5 141 if (info->is_momme)
c6d52747 142 analog->meaning->unit = SR_UNIT_MOMME;
e5d953b5 143 if (info->is_tola)
c6d52747 144 analog->meaning->unit = SR_UNIT_TOLA;
e5d953b5 145 if (info->is_percentage)
c6d52747 146 analog->meaning->unit = SR_UNIT_PERCENTAGE;
e5d953b5 147 if (info->is_piece)
c6d52747 148 analog->meaning->unit = SR_UNIT_PIECE;
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149
150 /* Measurement related flags */
151 if (info->is_unstable)
c6d52747 152 analog->meaning->mqflags |= SR_MQFLAG_UNSTABLE;
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153}
154
155SR_PRIV gboolean sr_kern_packet_valid(const uint8_t *buf)
156{
157 int buflen, s1, s2, cr, lf;
158
159 if ((buflen = get_buflen(buf)) < 0)
160 return FALSE;
161
162 s1 = (buflen == 14) ? 10 : 11;
163 s2 = (buflen == 14) ? 11 : 12;
164 cr = (buflen == 14) ? 12 : 13;
165 lf = (buflen == 14) ? 13 : 14;
166
167 /* Byte 0: Sign (must be '+' or '-' or ' '). */
168 if (buf[0] != '+' && buf[0] != '-' && buf[0] != ' ')
169 return FALSE;
170
171 /* Byte S1: Must be 'L' or 'G' or 'H' or ' '. */
172 if (buf[s1] != 'L' && buf[s1] != 'G' && buf[s1] != 'H' && buf[s1] != ' ')
173 return FALSE;
174
175 /* Byte S2: Must be 'U' or 'S' or 'E' or ' '. */
176 if (buf[s2] != 'U' && buf[s2] != 'S' && buf[s2] != 'E' && buf[s2] != ' ')
177 return FALSE;
178
179 /* Byte CR: Always '\r' (carriage return, 0x0d, 13) */
180 /* Byte LF: Always '\n' (newline, 0x0a, 10) */
181 if (buf[cr] != '\r' || buf[lf] != '\n')
182 return FALSE;
183
184 return TRUE;
185}
186
187/**
188 * Parse a protocol packet.
189 *
190 * @param buf Buffer containing the protocol packet. Must not be NULL.
191 * @param floatval Pointer to a float variable. That variable will contain the
192 * result value upon parsing success. Must not be NULL.
c6d52747 193 * @param analog Pointer to a struct sr_datafeed_analog. The struct will be
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194 * filled with data according to the protocol packet.
195 * Must not be NULL.
196 * @param info Pointer to a struct kern_info. The struct will be filled
197 * with data according to the protocol packet. Must not be NULL.
198 *
199 * @return SR_OK upon success, SR_ERR upon failure. Upon errors, the
200 * 'analog' variable contents are undefined and should not be used.
201 */
202SR_PRIV int sr_kern_parse(const uint8_t *buf, float *floatval,
c6d52747 203 struct sr_datafeed_analog *analog, void *info)
e5d953b5 204{
0b820550 205 int ret, digits = 0;
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206 struct kern_info *info_local;
207
208 info_local = (struct kern_info *)info;
209
210 info_local->buflen = get_buflen(buf);
211
0b820550 212 if ((ret = parse_value(buf, floatval, &digits, info_local)) != SR_OK) {
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213 sr_dbg("Error parsing value: %d.", ret);
214 return ret;
215 }
216
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217 analog->encoding->digits = digits;
218 analog->spec->spec_digits = digits;
219
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220 parse_flags(buf, info_local);
221 handle_flags(analog, floatval, info_local);
222
223 return SR_OK;
224}