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