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brymen-bm25x: properly set encoding digits

This commit is contained in:
Aurelien Jacobs 2016-08-16 18:08:03 +02:00 committed by Uwe Hermann
parent 1baf30f5f7
commit 25198a7e89
1 changed files with 21 additions and 20 deletions
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41
src/dmm/bm25x.c
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@ -94,36 +94,31 @@ static int decode_point(const uint8_t *buf)
return p;
}
static float scale_value(float val, int point, int digits)
static int decode_scale(int point, int digits)
{
int pos;
pos = point ? point + digits - MAX_DIGITS : 0;
switch (pos) {
case 0: return val;
case 1: return val * 1e-1;
case 2: return val * 1e-2;
case 3: return val * 1e-3;
if (pos < 0 || pos > 3) {
sr_dbg("Invalid decimal point %d (%d digits).", point, digits);
return 0;
}
sr_dbg("Invalid decimal point %d (%d digits).", point, digits);
return NAN;
return -pos;
}
static float decode_prefix(const uint8_t *buf)
static int decode_prefix(const uint8_t *buf)
{
if (buf[11] & 2) return 1e+6;
if (buf[11] & 1) return 1e+3;
if (buf[13] & 1) return 1e-3;
if (buf[13] & 2) return 1e-6;
if (buf[12] & 1) return 1e-9;
if (buf[11] & 2) return 6;
if (buf[11] & 1) return 3;
if (buf[13] & 1) return -3;
if (buf[13] & 2) return -6;
if (buf[12] & 1) return -9;
return 1.0f;
return 0;
}
static float decode_value(const uint8_t *buf)
static float decode_value(const uint8_t *buf, int *exponent)
{
float val = 0.0f;
int i, digit;
@ -137,7 +132,8 @@ static float decode_value(const uint8_t *buf)
val = 10.0 * val + digit;
}
return scale_value(val, decode_point(buf), i);
*exponent = decode_scale(decode_point(buf), i);
return val;
special:
if (decode_digit(1, buf) == 0 && decode_digit(2, buf) == 'L')
@ -149,6 +145,7 @@ special:
SR_PRIV int sr_brymen_bm25x_parse(const uint8_t *buf, float *floatval,
struct sr_datafeed_analog *analog, void *info)
{
int exponent = 0;
float val;
(void)info;
@ -204,12 +201,16 @@ SR_PRIV int sr_brymen_bm25x_parse(const uint8_t *buf, float *floatval,
analog->meaning->unit = SR_UNIT_FAHRENHEIT;
}
val = decode_value(buf) * decode_prefix(buf);
val = decode_value(buf, &exponent);
exponent += decode_prefix(buf);
val *= powf(10, exponent);
if (buf[3] & 1)
val = -val;
*floatval = val;
analog->encoding->digits = -exponent;
analog->spec->spec_digits = -exponent;
return SR_OK;
}