FlapJackApps/libdivecomputer
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Receive the entire packet before reporting buffer overflows.

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This commit is contained in:
Jef Driesen 2009-03-11 10:17:45 +00:00
parent ebfd5b4b1a
commit 00c3330e8d
1 changed files with 15 additions and 18 deletions
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33
src/suunto_vyper.c
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@ -464,30 +464,12 @@ suunto_vyper_read_dive (device_t *abstract, unsigned char data[], unsigned int s
return DEVICE_STATUS_PROTOCOL;
}
// Check for a buffer overflow.
if (size < nbytes + len) {
WARNING ("Insufficient buffer space available.");
return DEVICE_STATUS_MEMORY;
}
// Append the package to the output buffer.
memcpy (data + nbytes, answer + 2, len);
nbytes += len;
// The DC sends a null package (a package with length zero) when it
// has reached the end of its internal ring buffer. From this point on,
// the current dive has been overwritten with newer data. Therefore,
// we discard the current (incomplete) dive and end the transmission.
if (len == 0) {
WARNING ("Null package received.");
#ifndef NDEBUG
array_reverse_bytes (data, nbytes);
message ("Vyper%sProfile=\"", init ? "First" : "");
for (unsigned int i = 0; i < nbytes; ++i) {
message("%02x", data[i]);
}
message("\"\n");
#endif
if (result)
*result = 0;
return DEVICE_STATUS_SUCCESS;
@ -499,6 +481,15 @@ suunto_vyper_read_dive (device_t *abstract, unsigned char data[], unsigned int s
device_event_emit (abstract, DEVICE_EVENT_PROGRESS, progress);
}
// Append the package to the output buffer.
// Reporting of buffer overflows is delayed until the entire
// transfer is finished. This approach leaves no data behind in
// the serial receive buffer, and if this packet is part of the
// last incomplete dive, no error has to be reported at all.
if (size >= nbytes + len)
memcpy (data + nbytes, answer + 2, len);
nbytes += len;
// If a package is smaller than $SUUNTO_VYPER_PACKET_SIZE bytes,
// we assume it's the last packet and the transmission can be
// finished early. However, this approach does not work if the
@ -509,6 +500,12 @@ suunto_vyper_read_dive (device_t *abstract, unsigned char data[], unsigned int s
#endif
}
// Check for a buffer overflow.
if (size < nbytes) {
WARNING ("Insufficient buffer space available.");
return DEVICE_STATUS_MEMORY;
}
// The DC traverses its internal ring buffer backwards. The most recent
// dive is send first (which allows you to download only the new dives),
// but also the contents of each dive is reversed. Therefore, we reverse