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author | Lorenz Meier <lm@inf.ethz.ch> | 2014-08-31 19:53:01 +0200 |
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committer | Lorenz Meier <lm@inf.ethz.ch> | 2014-08-31 19:53:01 +0200 |
commit | ee913202991f2a015904b1570bd9f5a62865e5c7 (patch) | |
tree | 3297a0e1124922d5183562cfb6e256bb57ab6473 /src/drivers/sf0x | |
parent | 7a253d50f8da7a6f8176f784c196b85bcae3c8f1 (diff) | |
download | px4-firmware-ee913202991f2a015904b1570bd9f5a62865e5c7.tar.gz px4-firmware-ee913202991f2a015904b1570bd9f5a62865e5c7.tar.bz2 px4-firmware-ee913202991f2a015904b1570bd9f5a62865e5c7.zip |
SF02/F driver: Improve parsing
Diffstat (limited to 'src/drivers/sf0x')
-rw-r--r-- | src/drivers/sf0x/sf0x.cpp | 40 |
1 files changed, 16 insertions, 24 deletions
diff --git a/src/drivers/sf0x/sf0x.cpp b/src/drivers/sf0x/sf0x.cpp index d7780e9e8..cf0419075 100644 --- a/src/drivers/sf0x/sf0x.cpp +++ b/src/drivers/sf0x/sf0x.cpp @@ -520,11 +520,9 @@ SF0X::collect() /* clear buffer if last read was too long ago */ uint64_t read_elapsed = hrt_elapsed_time(&_last_read); + /* timed out - retry */ if (read_elapsed > (SF0X_CONVERSION_INTERVAL * 2)) { _linebuf_index = 0; - } else if (_linebuf_index > 0) { - /* increment to next read position */ - _linebuf_index++; } /* the buffer for read chars is buflen minus null termination */ @@ -550,18 +548,19 @@ SF0X::collect() return -EAGAIN; } - /* we did increment the index to the next position already, so just add the additional fields */ - _linebuf_index += (ret - 1); + /* let the write pointer point to the next free entry */ + _linebuf_index += ret; _last_read = hrt_absolute_time(); - if (_linebuf_index < 1) { - /* we need at least the two end bytes to make sense of this string */ + /* require a reasonable amount of minimum bytes */ + if (_linebuf_index < 6) { + /* we need at this format: x.xx\r\n */ return -EAGAIN; - } else if (_linebuf[_linebuf_index - 1] != '\r' || _linebuf[_linebuf_index] != '\n') { + } else if (_linebuf[_linebuf_index - 2] != '\r' || _linebuf[_linebuf_index - 1] != '\n') { - if (_linebuf_index >= readlen - 1) { + if (_linebuf_index == readlen) { /* we have a full buffer, but no line ending - abort */ _linebuf_index = 0; perf_count(_comms_errors); @@ -577,9 +576,7 @@ SF0X::collect() bool valid; /* enforce line ending */ - unsigned lend = (_linebuf_index < (sizeof(_linebuf) - 1)) ? _linebuf_index : (sizeof(_linebuf) - 1); - - _linebuf[lend] = '\0'; + _linebuf[_linebuf_index] = '\0'; if (_linebuf[0] == '-' && _linebuf[1] == '-' && _linebuf[2] == '.') { si_units = -1.0f; @@ -591,17 +588,12 @@ SF0X::collect() valid = false; /* wipe out partially read content from last cycle(s), check for dot */ - for (unsigned i = 0; i < (lend - 2); i++) { + for (unsigned i = 0; i < (_linebuf_index - 2); i++) { if (_linebuf[i] == '\n') { - /* allocate temporary buffer */ - char buf[sizeof(_linebuf)]; - /* copy remainder of buffer (2nd measurement) to temporary buffer */ - memcpy(buf, &_linebuf[i+1], (lend + 1) - (i + 1)); - /* copy temporary buffer to beginning of line buffer, - * effectively overwriting a previous temporary - * measurement - */ - memcpy(_linebuf, buf, (lend + 1) - (i + 1)); + /* wipe out any partial measurements */ + for (unsigned j = 0; j <= i; j++) { + _linebuf[j] = ' '; + } } /* we need a digit before the dot and a dot for a valid number */ @@ -613,8 +605,8 @@ SF0X::collect() if (valid) { si_units = strtod(_linebuf, &end); - /* we require at least 3 characters for a valid number */ - if (end > _linebuf + 3) { + /* we require at least four characters for a valid number */ + if (end > _linebuf + 4) { valid = true; } else { si_units = -1.0f; |