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DataFlash: use const char * rather than fixed array lengths in LogStructure

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Previously tridge found that using const char * here meant that the
data segment (and thus RAM usage) would increase.

This doesn't seem to be a problem now.
This commit is contained in:
Peter Barker 2018-02-23 11:06:45 +11:00 committed by Peter Barker
parent 014702fc64
commit b36f1c558d
3 changed files with 67 additions and 39 deletions
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74
libraries/DataFlash/DataFlash.cpp
View File

@ -250,11 +250,20 @@ bool DataFlash_Class::validate_structure(const struct LogStructure *logstructure
Debug("offset=%d ID=%d NAME=%s\n", i, logstructure->msg_type, logstructure->name);
#endif
// names must be null-terminated
if (logstructure->name[4] != '\0') {
Debug("Message name not NULL-terminated");
passed = false;
}
// fields must be null-terminated
#define CHECK_ENTRY(fieldname,fieldname_s,fieldlen) \
do { \
if (strnlen(logstructure->fieldname, fieldlen) > fieldlen-1) { \
Debug("Message " fieldname_s " not NULL-terminated or too long"); \
passed = false; \
} \
} while (false)
CHECK_ENTRY(name, "name", LS_NAME_SIZE);
CHECK_ENTRY(format, "format", LS_FORMAT_SIZE);
CHECK_ENTRY(labels, "labels", LS_LABELS_SIZE);
CHECK_ENTRY(units, "units", LS_UNITS_SIZE);
CHECK_ENTRY(multipliers, "multipliers", LS_MULTIPLIERS_SIZE);
#undef CHECK_ENTRY
// ensure each message ID is only used once
if (seen_ids[logstructure->msg_type]) {
@ -753,29 +762,32 @@ DataFlash_Class::log_write_fmt *DataFlash_Class::msg_fmt_for_name(const char *na
log_write_fmts = f;
#if CONFIG_HAL_BOARD == HAL_BOARD_SITL
char ls_name[LS_NAME_SIZE] = {};
char ls_format[LS_FORMAT_SIZE] = {};
char ls_labels[LS_LABELS_SIZE] = {};
char ls_units[LS_UNITS_SIZE] = {};
char ls_multipliers[LS_MULTIPLIERS_SIZE] = {};
struct LogStructure ls = {
f->msg_type,
f->msg_len,
"",
"",
"",
"",
""
ls_name,
ls_format,
ls_labels,
ls_units,
ls_multipliers
};
memcpy((char*)ls.name, f->name, MIN(sizeof(ls.name), strlen(f->name)));
memcpy((char*)ls.format, f->fmt, MIN(sizeof(ls.format), strlen(f->fmt)));
memcpy((char*)ls.labels, f->labels, MIN(sizeof(ls.labels), strlen(f->labels)));
memcpy((char*)ls_name, f->name, MIN(sizeof(ls_name), strlen(f->name)));
memcpy((char*)ls_format, f->fmt, MIN(sizeof(ls_format), strlen(f->fmt)));
memcpy((char*)ls_labels, f->labels, MIN(sizeof(ls_labels), strlen(f->labels)));
if (f->units != nullptr) {
memcpy((char*)ls.units, f->units, MIN(sizeof(ls.units), strlen(f->units)));
memcpy((char*)ls_units, f->units, MIN(sizeof(ls_units), strlen(f->units)));
} else {
memset((char*)ls.units, '\0', sizeof(ls.units));
memset((char*)ls.units, '?', strlen(ls.format));
memset((char*)ls_units, '?', MIN(sizeof(ls_format), strlen(f->fmt)));
}
if (f->mults != nullptr) {
memcpy((char*)ls.multipliers, f->mults, MIN(sizeof(ls.multipliers), strlen(f->mults)));
memcpy((char*)ls_multipliers, f->mults, MIN(sizeof(ls_multipliers), strlen(f->mults)));
} else {
memset((char*)ls.multipliers, '\0', sizeof(ls.multipliers));
memset((char*)ls.multipliers, '?', strlen(ls.format));
memset((char*)ls_multipliers, '?', MIN(sizeof(ls_format), strlen(f->fmt)));
}
validate_structure(&ls, (int16_t)-1);
#endif
@ -816,6 +828,10 @@ int16_t DataFlash_Class::find_free_msg_type() const
return -1;
}
/*
* It is assumed that logstruct's char* variables are valid strings of
* maximum lengths for those fields (given in LogStructure.h e.g. LS_NAME_SIZE)
*/
bool DataFlash_Class::fill_log_write_logstructure(struct LogStructure &logstruct, const uint8_t msg_type) const
{
// find log structure information corresponding to msg_type:
@ -831,23 +847,23 @@ bool DataFlash_Class::fill_log_write_logstructure(struct LogStructure &logstruct
}
logstruct.msg_type = msg_type;
strncpy((char*)logstruct.name, f->name, sizeof(logstruct.name)); /* cast away the "const" (*gulp*) */
strncpy((char*)logstruct.format, f->fmt, sizeof(logstruct.format));
strncpy((char*)logstruct.labels, f->labels, sizeof(logstruct.labels));
strncpy((char*)logstruct.name, f->name, LS_NAME_SIZE);
strncpy((char*)logstruct.format, f->fmt, LS_FORMAT_SIZE);
strncpy((char*)logstruct.labels, f->labels, LS_LABELS_SIZE);
if (f->units != nullptr) {
strncpy((char*)logstruct.units, f->units, sizeof(logstruct.units));
strncpy((char*)logstruct.units, f->units, LS_UNITS_SIZE);
} else {
memset((char*)logstruct.units, '\0', sizeof(logstruct.units));
memset((char*)logstruct.units, '?', strlen(logstruct.format));
memset((char*)logstruct.units, '\0', LS_UNITS_SIZE);
memset((char*)logstruct.units, '?', MIN(LS_UNITS_SIZE,strlen(logstruct.format)));
}
if (f->mults != nullptr) {
strncpy((char*)logstruct.multipliers, f->mults, sizeof(logstruct.multipliers));
strncpy((char*)logstruct.multipliers, f->mults, LS_MULTIPLIERS_SIZE);
} else {
memset((char*)logstruct.multipliers, '\0', sizeof(logstruct.multipliers));
memset((char*)logstruct.multipliers, '?', strlen(logstruct.format));
memset((char*)logstruct.multipliers, '\0', LS_MULTIPLIERS_SIZE);
memset((char*)logstruct.multipliers, '?', MIN(LS_MULTIPLIERS_SIZE, strlen(logstruct.format)));
// special magic to set units/mults for TimeUS, by far and
// away the most common first field
if (!strncmp(logstruct.labels, "TimeUS,", MIN(strlen(logstruct.labels), strlen("TimeUS,")))) {
if (!strncmp(logstruct.labels, "TimeUS,", MIN(LS_LABELS_SIZE, strlen("TimeUS,")))) {
((char*)(logstruct.units))[0] = 's';
((char*)(logstruct.multipliers))[0] = 'F';
}

15
libraries/DataFlash/DataFlash_Backend.cpp
View File

@ -146,15 +146,20 @@ void DataFlash_Backend::WriteMoreStartupMessages()
bool DataFlash_Backend::Log_Write_Emit_FMT(uint8_t msg_type)
{
// get log structure from front end:
char ls_name[LS_NAME_SIZE] = {};
char ls_format[LS_FORMAT_SIZE] = {};
char ls_labels[LS_LABELS_SIZE] = {};
char ls_units[LS_UNITS_SIZE] = {};
char ls_multipliers[LS_MULTIPLIERS_SIZE] = {};
struct LogStructure logstruct = {
// these will be overwritten, but need to keep the compiler happy:
0,
0,
"IGNO",
"",
"",
"",
""
ls_name,
ls_format,
ls_labels,
ls_units,
ls_multipliers
};
if (!_front.fill_log_write_logstructure(logstruct, msg_type)) {
// this is a bug; we've been asked to write out the FMT

17
libraries/DataFlash/LogStructure.h
View File

@ -17,13 +17,20 @@
struct LogStructure {
uint8_t msg_type;
uint8_t msg_len;
const char name[5];
const char format[16];
const char labels[64];
const char units[16];
const char multipliers[16];
const char *name;
const char *format;
const char *labels;
const char *units;
const char *multipliers;
};
// maximum lengths of fields in LogStructure, including trailing nulls
static const uint8_t LS_NAME_SIZE = 5;
static const uint8_t LS_FORMAT_SIZE = 17;
static const uint8_t LS_LABELS_SIZE = 65;
static const uint8_t LS_UNITS_SIZE = 17;
static const uint8_t LS_MULTIPLIERS_SIZE = 17;
/*
log structures common to all vehicle types
*/