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Locate the most recent dive using the logbook pointers

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I received a bug report from a device which failed to download new dives
after a reset (probably caused by an empty battery). This reset appears
to reset the internal dive counter back to zero, and also resets the
write pointer back to the begin of the logbook ringbuffer, but leaves
the existing logbook entries in place. The result is that the logic to
find the most recent dive based on the highest internal dive counter,
will be wrong because it finds those old entries.

The discovery of the logbook (and profile) write pointers eliminates the
need to search for the most recent logbook entry.
This commit is contained in:
Jef Driesen 2017-08-09 10:33:21 +02:00
parent f7bcbb5828
commit 2813d61f65
1 changed files with 22 additions and 25 deletions
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47
src/cressi_leonardo.c
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@ -448,32 +448,25 @@ cressi_leonardo_extract_dives (dc_device_t *abstract, const unsigned char data[]
if (size < SZ_MEMORY)
return DC_STATUS_DATAFORMAT;
// Locate the most recent dive.
// The device maintains an internal counter which is incremented for every
// dive, and the current value at the time of the dive is stored in the
// dive header. Thus the most recent dive will have the highest value.
unsigned int count = 0;
unsigned int latest = 0;
unsigned int maximum = 0;
for (unsigned int i = 0; i < RB_LOGBOOK_COUNT; ++i) {
unsigned int offset = RB_LOGBOOK_BEGIN + i * RB_LOGBOOK_SIZE;
// Get the number of dives.
//unsigned int ndives = array_uint16_le(data + 0x62);
// Ignore uninitialized header entries.
if (array_isequal (data + offset, RB_LOGBOOK_SIZE, 0xFF))
break;
// Get the logbook pointer.
unsigned int last = array_uint16_le(data + 0x64);
if (last < RB_LOGBOOK_BEGIN || last > RB_LOGBOOK_END ||
((last - RB_LOGBOOK_BEGIN) % RB_LOGBOOK_SIZE) != 0) {
ERROR (context, "Invalid logbook pointer (0x%04x).", last);
return DC_STATUS_DATAFORMAT;
}
// Get the internal dive number.
unsigned int current = array_uint16_le (data + offset);
if (current == 0xFFFF) {
WARNING (context, "Unexpected internal dive number found.");
break;
}
if (current > maximum) {
maximum = current;
latest = i;
}
// Convert to an index.
unsigned int latest = (last - RB_LOGBOOK_BEGIN) / RB_LOGBOOK_SIZE;
count++;
// Get the profile pointer.
unsigned int eop = array_uint16_le(data + 0x66);
if (eop < RB_PROFILE_BEGIN || last > RB_PROFILE_END) {
ERROR (context, "Invalid profile pointer (0x%04x).", eop);
return DC_STATUS_DATAFORMAT;
}
unsigned char *buffer = (unsigned char *) malloc (RB_LOGBOOK_SIZE + RB_PROFILE_END - RB_PROFILE_BEGIN);
@ -482,12 +475,16 @@ cressi_leonardo_extract_dives (dc_device_t *abstract, const unsigned char data[]
return DC_STATUS_NOMEMORY;
}
unsigned int previous = 0;
unsigned int previous = eop;
unsigned int remaining = RB_PROFILE_END - RB_PROFILE_BEGIN;
for (unsigned int i = 0; i < count; ++i) {
for (unsigned int i = 0; i < RB_LOGBOOK_COUNT; ++i) {
unsigned int idx = (latest + RB_LOGBOOK_COUNT - i) % RB_LOGBOOK_COUNT;
unsigned int offset = RB_LOGBOOK_BEGIN + idx * RB_LOGBOOK_SIZE;
// Ignore uninitialized header entries.
if (array_isequal (data + offset, RB_LOGBOOK_SIZE, 0xFF))
break;
// Get the ringbuffer pointers.
unsigned int header = array_uint16_le (data + offset + 2);
unsigned int footer = array_uint16_le (data + offset + 4);