libsigrok/src/scale/kern.c

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/*
* This file is part of the libsigrok project.
*
* Copyright (C) 2015 Uwe Hermann <uwe@hermann-uwe.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
/*
* KERN scale protocol parser.
*/
#include <config.h>
#include <string.h>
#include <ctype.h>
#include <math.h>
#include <glib.h>
#include <libsigrok/libsigrok.h>
#include "libsigrok-internal.h"
#define LOG_PREFIX "kern"
static int get_buflen(const uint8_t *buf)
{
/* Find out whether it's a 14-byte or 15-byte packet. */
if (buf[12] == '\r' && buf[13] == '\n')
return 14;
else if (buf[13] == '\r' && buf[14] == '\n')
return 15;
else
return -1;
}
static int parse_value(const uint8_t *buf, float *result,
const struct kern_info *info)
{
char *strval;
float floatval;
int s2, len;
s2 = (info->buflen == 14) ? 11 : 12;
len = (info->buflen == 14) ? 8 : 9;
if (buf[s2] == 'E') {
/* Display: "o-Err" or "u-Err", but protocol only has 'E'. */
sr_spew("Over/under limit.");
*result = INFINITY;
return SR_OK;
}
strval = g_strndup((const char *)buf, len);
floatval = g_ascii_strtod(strval, NULL);
g_free(strval);
*result = floatval;
return SR_OK;
}
static void parse_flags(const uint8_t *buf, struct kern_info *info)
{
int u1, u2, s2;
u1 = (info->buflen == 14) ? 8 : 9;
u2 = (info->buflen == 14) ? 9 : 10;
s2 = (info->buflen == 14) ? 11 : 12;
/* Bytes U1, U2: Unit */
info->is_gram = (buf[u1] == ' ' && buf[u2] == 'G');
info->is_carat = (buf[u1] == 'C' && buf[u2] == 'T');
info->is_ounce = (buf[u1] == 'O' && buf[u2] == 'Z');
info->is_pound = (buf[u1] == 'L' && buf[u2] == 'B');
info->is_troy_ounce = (buf[u1] == 'O' && buf[u2] == 'T');
info->is_pennyweight = (buf[u1] == 'D' && buf[u2] == 'W');
info->is_grain = (buf[u1] == 'G' && buf[u2] == 'R');
info->is_tael = (buf[u1] == 'T' && buf[u2] == 'L');
info->is_momme = (buf[u1] == 'M' && buf[u2] == 'O');
info->is_tola = (buf[u1] == 't' && buf[u2] == 'o');
info->is_percentage = (buf[u1] == ' ' && buf[u2] == '%');
info->is_piece = (buf[u1] == 'P' && buf[u2] == 'C');
/*
* Note: The display can show 3 different variants for Tael:
* "Hong Kong", "Singapore, Malaysia", and "Taiwan". However,
* in the protocol only one Tael value ('T', 'L') is used, thus
* we cannot distinguish between them.
*/
/* Byte S1: Result / data type (currently unused) */
/* Byte S2: Status of the data */
info->is_unstable = (buf[s2] == 'U');
info->is_stable = (buf[s2] == 'S');
info->is_error = (buf[s2] == 'E');
/* Space: no special status. */
/* Byte CR: Always '\r' (carriage return, 0x0d, 13) */
/* Byte LF: Always '\n' (newline, 0x0a, 10) */
}
static void handle_flags(struct sr_datafeed_analog *analog, float *floatval,
const struct kern_info *info)
{
(void)floatval;
/* Measured quantity: mass. */
analog->mq = SR_MQ_MASS;
/* Unit */
if (info->is_gram)
analog->unit = SR_UNIT_GRAM;
if (info->is_carat)
analog->unit = SR_UNIT_CARAT;
if (info->is_ounce)
analog->unit = SR_UNIT_OUNCE;
if (info->is_pound)
analog->unit = SR_UNIT_POUND;
if (info->is_troy_ounce)
analog->unit = SR_UNIT_TROY_OUNCE;
if (info->is_pennyweight)
analog->unit = SR_UNIT_PENNYWEIGHT;
if (info->is_grain)
analog->unit = SR_UNIT_GRAIN;
if (info->is_tael)
analog->unit = SR_UNIT_TAEL;
if (info->is_momme)
analog->unit = SR_UNIT_MOMME;
if (info->is_tola)
analog->unit = SR_UNIT_TOLA;
if (info->is_percentage)
analog->unit = SR_UNIT_PERCENTAGE;
if (info->is_piece)
analog->unit = SR_UNIT_PIECE;
/* Measurement related flags */
if (info->is_unstable)
analog->mqflags |= SR_MQFLAG_UNSTABLE;
}
SR_PRIV gboolean sr_kern_packet_valid(const uint8_t *buf)
{
int buflen, s1, s2, cr, lf;
if ((buflen = get_buflen(buf)) < 0)
return FALSE;
s1 = (buflen == 14) ? 10 : 11;
s2 = (buflen == 14) ? 11 : 12;
cr = (buflen == 14) ? 12 : 13;
lf = (buflen == 14) ? 13 : 14;
/* Byte 0: Sign (must be '+' or '-' or ' '). */
if (buf[0] != '+' && buf[0] != '-' && buf[0] != ' ')
return FALSE;
/* Byte S1: Must be 'L' or 'G' or 'H' or ' '. */
if (buf[s1] != 'L' && buf[s1] != 'G' && buf[s1] != 'H' && buf[s1] != ' ')
return FALSE;
/* Byte S2: Must be 'U' or 'S' or 'E' or ' '. */
if (buf[s2] != 'U' && buf[s2] != 'S' && buf[s2] != 'E' && buf[s2] != ' ')
return FALSE;
/* Byte CR: Always '\r' (carriage return, 0x0d, 13) */
/* Byte LF: Always '\n' (newline, 0x0a, 10) */
if (buf[cr] != '\r' || buf[lf] != '\n')
return FALSE;
return TRUE;
}
/**
* Parse a protocol packet.
*
* @param buf Buffer containing the protocol packet. Must not be NULL.
* @param floatval Pointer to a float variable. That variable will contain the
* result value upon parsing success. Must not be NULL.
* @param analog Pointer to a struct sr_datafeed_analog. The struct will be
* filled with data according to the protocol packet.
* Must not be NULL.
* @param info Pointer to a struct kern_info. The struct will be filled
* with data according to the protocol packet. Must not be NULL.
*
* @return SR_OK upon success, SR_ERR upon failure. Upon errors, the
* 'analog' variable contents are undefined and should not be used.
*/
SR_PRIV int sr_kern_parse(const uint8_t *buf, float *floatval,
struct sr_datafeed_analog *analog, void *info)
{
int ret;
struct kern_info *info_local;
info_local = (struct kern_info *)info;
info_local->buflen = get_buflen(buf);
if ((ret = parse_value(buf, floatval, info_local)) != SR_OK) {
sr_dbg("Error parsing value: %d.", ret);
return ret;
}
parse_flags(buf, info_local);
handle_flags(analog, floatval, info_local);
return SR_OK;
}