From: Gerhard Sittig <redacted>
Date: Mon, 21 Sep 2020 18:20:13 +0000 (+0200)
Subject: brymen-dmm: rephrase bfunc and value text parsing
X-Git-Url: https://sigrok.org/gitweb/?p=libsigrok.git;a=commitdiff_plain;h=66b349841a7db1ec143d9cec2316ece99a741d04

brymen-dmm: rephrase bfunc and value text parsing

When the BM850s response packet's payload gets interpreted, the DLE/STX
transport envelope is not of interest. Rephrase the bitfield inspection
to better reflect that 'bfunc' indicators get accessed (match the vendor's
documentation). Rephrase the calling parse routine to unobfuscate the text
field access. Unclutter assignments for the analog feed. Use a shorter
layout in debug messages, reflect raw input data and conversion results.
---

diff --git a/src/hardware/brymen-dmm/parser.c b/src/hardware/brymen-dmm/parser.c
index baab57d9..9811012b 100644
--- a/src/hardware/brymen-dmm/parser.c
+++ b/src/hardware/brymen-dmm/parser.c
@@ -195,24 +195,24 @@ static int parse_value(const char *txt, size_t len, float *floatval)
 	return SR_OK;
 }
 
-static void parse_flags(const uint8_t *buf, struct brymen_flags *info)
+static void parse_flags(const uint8_t *bfunc, struct brymen_flags *info)
 {
-	info->is_low_batt	= (buf[4 + 3] & (1 << 7)) != 0;
-
-	info->is_decibel	= (buf[4 + 1] & (1 << 5)) != 0;
-	info->is_duty_cycle	= (buf[4 + 1] & (1 << 3)) != 0;
-	info->is_hertz		= (buf[4 + 1] & (1 << 2)) != 0;
-	info->is_amp		= (buf[4 + 1] & (1 << 1)) != 0;
-	info->is_beep		= (buf[4 + 1] & (1 << 0)) != 0;
-
-	info->is_ohm		= (buf[4 + 0] & (1 << 7)) != 0;
-	info->is_fahrenheit	= (buf[4 + 0] & (1 << 6)) != 0;
-	info->is_celsius	= (buf[4 + 0] & (1 << 5)) != 0;
-	info->is_diode		= (buf[4 + 0] & (1 << 4)) != 0;
-	info->is_capacitance	= (buf[4 + 0] & (1 << 3)) != 0;
-	info->is_volt		= (buf[4 + 0] & (1 << 2)) != 0;
-	info->is_dc		= (buf[4 + 0] & (1 << 1)) != 0;
-	info->is_ac		= (buf[4 + 0] & (1 << 0)) != 0;
+	info->is_low_batt	= (bfunc[3] & (1 << 7)) != 0;
+
+	info->is_decibel	= (bfunc[1] & (1 << 5)) != 0;
+	info->is_duty_cycle	= (bfunc[1] & (1 << 3)) != 0;
+	info->is_hertz		= (bfunc[1] & (1 << 2)) != 0;
+	info->is_amp		= (bfunc[1] & (1 << 1)) != 0;
+	info->is_beep		= (bfunc[1] & (1 << 0)) != 0;
+
+	info->is_ohm		= (bfunc[0] & (1 << 7)) != 0;
+	info->is_fahrenheit	= (bfunc[0] & (1 << 6)) != 0;
+	info->is_celsius	= (bfunc[0] & (1 << 5)) != 0;
+	info->is_diode		= (bfunc[0] & (1 << 4)) != 0;
+	info->is_capacitance	= (bfunc[0] & (1 << 3)) != 0;
+	info->is_volt		= (bfunc[0] & (1 << 2)) != 0;
+	info->is_dc		= (bfunc[0] & (1 << 1)) != 0;
+	info->is_ac		= (bfunc[0] & (1 << 0)) != 0;
 }
 
 SR_PRIV int brymen_parse(const uint8_t *buf, float *floatval,
@@ -221,26 +221,27 @@ SR_PRIV int brymen_parse(const uint8_t *buf, float *floatval,
 	struct brymen_flags flags;
 	struct brymen_header *hdr;
 	uint8_t *bfunc;
-	int asciilen;
+	const char *txt;
+	int txtlen;
+	int ret;
 
 	(void)info;
 
 	hdr = (void *)buf;
 	bfunc = (uint8_t *)(buf + sizeof(struct brymen_header));
-
-	analog->meaning->mqflags = 0;
-
-	/* Give some debug info about the package. */
-	asciilen = hdr->len - 4;
-	sr_dbg("DMM flags: %.2x %.2x %.2x %.2x",
-	       bfunc[3], bfunc[2], bfunc[1], bfunc[0]);
-	/* Value is an ASCII string. */
-	sr_dbg("DMM packet: \"%.*s\"", asciilen, bfunc + 4);
-
-	parse_flags(buf, &flags);
-	if (parse_value((const char *)(bfunc + 4), asciilen, floatval) != SR_OK)
+	txt = (const char *)&bfunc[4];
+	txtlen = hdr->len - 4;
+	sr_dbg("DMM bfunc: %02x %02x %02x %02x, text '%.*s'",
+		bfunc[3], bfunc[2], bfunc[1], bfunc[0], txtlen, txt);
+
+	memset(&flags, 0, sizeof(flags));
+	parse_flags(bfunc, &flags);
+	ret = parse_value(txt, txtlen, floatval);
+	sr_dbg("floatval: %f, ret %d", *floatval, ret);
+	if (ret != SR_OK)
 		return SR_ERR;
 
+	analog->meaning->mqflags = 0;
 	if (flags.is_volt) {
 		analog->meaning->mq = SR_MQ_VOLTAGE;
 		analog->meaning->unit = SR_UNIT_VOLT;