Document if or why sometimes digits/spec_digits is 0.

[libsigrok.git] / src / hardware / brymen-bm86x / protocol.c

diff --git a/src/hardware/brymen-bm86x/protocol.c b/src/hardware/brymen-bm86x/protocol.c
index 353ae02bfd3f84b88f74e80fa592fedf83dd8524..f6ccc3068fe6445fbd7f0e249d1434afa0494524 100644 (file)
--- a/src/hardware/brymen-bm86x/protocol.c
+++ b/src/hardware/brymen-bm86x/protocol.c
@@ -46,24 +46,33 @@ static const char char_map[128] = {
 
 static int brymen_bm86x_parse_digits(const unsigned char *buf, int length,
                                      char *str, float *floatval,
-                                     char *temp_unit, int flag)
+                                     char *temp_unit, int *digits, int flag)
 {
        char c, *p = str;
        int i, ret;
 
+       *digits = INT_MIN;
+
        if (buf[0] & flag)
                *p++ = '-';
        for (i = 0; i < length; i++) {
-               if (i && i < 5 && buf[i+1] & 0x01)
+               if (i && i < 5 && buf[i+1] & 0x01) {
                        *p++ = '.';
+                       *digits = 0;
+               }
                c = char_map[buf[i+1] >> 1];
                if (i == 5 && (c == 'C' || c == 'F'))
                        *temp_unit = c;
-               else if (c)
+               else if (c) {
                        *p++ = c;
+                       (*digits)++;
+               }
        }
        *p = 0;
 
+       if (*digits < 0)
+               *digits = 0;
+
        if ((ret = sr_atof_ascii(str, floatval))) {
                sr_dbg("invalid float string: '%s'", str);
                return ret;
@@ -76,13 +85,13 @@ static void brymen_bm86x_parse(unsigned char *buf, float *floatval,
                                struct sr_datafeed_analog *analog)
 {
        char str[16], temp_unit;
-       int ret1, ret2, over_limit;
+       int ret1, ret2, digits[2], over_limit;
 
        ret1 = brymen_bm86x_parse_digits(buf+2, 6, str, &floatval[0],
-                                        &temp_unit, 0x80);
+                                        &temp_unit, &digits[0], 0x80);
        over_limit = strstr(str, "0L") || strstr(str, "0.L");
        ret2 = brymen_bm86x_parse_digits(buf+9, 4, str, &floatval[1],
-                                        &temp_unit, 0x10);
+                                        &temp_unit, &digits[1], 0x10);
 
        /* main display */
        if (ret1 == SR_OK || over_limit) {
@@ -144,13 +153,16 @@ static void brymen_bm86x_parse(unsigned char *buf, float *floatval,
                        buf[15] &= ~0x04;
 
                /* SI prefix */
-               if (buf[14] & 0x40)  floatval[0] *= 1e-9;  /* n */
-               if (buf[15] & 0x08)  floatval[0] *= 1e-6;  /* µ */
-               if (buf[15] & 0x04)  floatval[0] *= 1e-3;  /* m */
-               if (buf[15] & 0x40)  floatval[0] *= 1e3;   /* k */
-               if (buf[15] & 0x20)  floatval[0] *= 1e6;   /* M */
+               if (buf[14] & 0x40)  { floatval[0] *= 1e-9; digits[0] += 9; }  /* n */
+               if (buf[15] & 0x08)  { floatval[0] *= 1e-6; digits[0] += 6; }  /* µ */
+               if (buf[15] & 0x04)  { floatval[0] *= 1e-3; digits[0] += 3; }  /* m */
+               if (buf[15] & 0x40)  { floatval[0] *= 1e3;  digits[0] -= 3; }  /* k */
+               if (buf[15] & 0x20)  { floatval[0] *= 1e6;  digits[0] -= 6; }  /* M */
 
                if (over_limit)      floatval[0] = INFINITY;
+
+               analog[0].encoding->digits  = digits[0];
+               analog[0].spec->spec_digits = digits[0];
        }
 
        /* secondary display */
@@ -180,10 +192,13 @@ static void brymen_bm86x_parse(unsigned char *buf, float *floatval,
                if (buf[9] & 0x20)  analog[1].meaning->mqflags |= SR_MQFLAG_AC;
 
                /* SI prefix */
-               if (buf[ 9] & 0x01)  floatval[1] *= 1e-6;  /* µ */
-               if (buf[ 9] & 0x02)  floatval[1] *= 1e-3;  /* m */
-               if (buf[14] & 0x02)  floatval[1] *= 1e3;   /* k */
-               if (buf[14] & 0x01)  floatval[1] *= 1e6;   /* M */
+               if (buf[ 9] & 0x01)  { floatval[1] *= 1e-6; digits[1] += 6; }  /* µ */
+               if (buf[ 9] & 0x02)  { floatval[1] *= 1e-3; digits[1] += 3; }  /* m */
+               if (buf[14] & 0x02)  { floatval[1] *= 1e3;  digits[1] -= 3; }  /* k */
+               if (buf[14] & 0x01)  { floatval[1] *= 1e6;  digits[1] -= 6; }  /* M */
+
+               analog[1].encoding->digits  = digits[1];
+               analog[1].spec->spec_digits = digits[1];
        }
 
        if (buf[9] & 0x80)
@@ -203,6 +218,7 @@ static void brymen_bm86x_handle_packet(const struct sr_dev_inst *sdi,
 
        devc = sdi->priv;
 
+       /* Note: digits/spec_digits will be overridden later. */
        sr_analog_init(&analog[0], &encoding[0], &meaning[0], &spec[0], 0);
        sr_analog_init(&analog[1], &encoding[1], &meaning[1], &spec[1], 0);