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Rewrite the incremental parser function.

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This commit is contained in:
Jef Driesen 2009-12-03 12:43:29 +00:00
parent 421f4ed1d6
commit 7f983e29fe
1 changed files with 55 additions and 51 deletions
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106
src/reefnet_sensusultra.c
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@ -630,65 +630,64 @@ reefnet_sensusultra_device_sense (device_t *abstract, unsigned char *data, unsig
static device_status_t static device_status_t
reefnet_sensusultra_parse (reefnet_sensusultra_device_t *device, reefnet_sensusultra_parse (reefnet_sensusultra_device_t *device,
const unsigned char data[], unsigned int size, unsigned int *pprevious, const unsigned char data[], unsigned int *premaining, unsigned int *pprevious,
int *aborted, dive_callback_t callback, void *userdata) int *aborted, dive_callback_t callback, void *userdata)
{ {
const unsigned char header[4] = {0x00, 0x00, 0x00, 0x00}; const unsigned char header[4] = {0x00, 0x00, 0x00, 0x00};
const unsigned char footer[4] = {0xFF, 0xFF, 0xFF, 0xFF}; const unsigned char footer[4] = {0xFF, 0xFF, 0xFF, 0xFF};
// Initialize the data stream offsets. // Initialize the data stream pointers.
unsigned int previous = (pprevious ? *pprevious : size); const unsigned char *current = data + *premaining;
unsigned int current = size; const unsigned char *previous = data + *pprevious;
if (current + 4 > previous)
current = (previous >= 4 ? previous - 4 : 0);
// Search the data stream for start markers. // Search the data stream for header markers.
while (current > 0) { while ((current = array_search_backward (data, current - data, header, sizeof (header))) != NULL) {
current--; // Move the pointer to the begin of the header.
if (memcmp (data + current, header, sizeof (header)) == 0) { current -= sizeof (header);
// Once a start marker is found, start searching
// for the corresponding stop marker. The search is
// now limited to the start of the previous dive.
int found = 0;
unsigned int offset = current + 16; // Skip non-sample data.
while (offset + 4 <= previous) {
if (memcmp (data + offset, footer, sizeof (footer)) == 0) {
found = 1;
break;
} else {
offset++;
}
}
// Report an error if no stop marker was found. // Once a header marker is found, start searching
if (!found) { // for the corresponding footer marker. The search is
WARNING ("No stop marker present."); // now limited to the start of the previous dive.
return DEVICE_STATUS_ERROR; if (previous - current >= 16) {
} previous = array_search_forward (current + 16, previous - current - 16, footer, sizeof (footer));
} else {
// Automatically abort when a dive is older than the provided timestamp. previous = NULL;
unsigned int timestamp = array_uint32_le (data + current + 4);
if (device && timestamp <= device->timestamp) {
if (aborted)
*aborted = 1;
return DEVICE_STATUS_SUCCESS;
}
if (callback && !callback (data + current, offset + 4 - current, userdata)) {
if (aborted)
*aborted = 1;
return DEVICE_STATUS_SUCCESS;
}
// Prepare for the next dive.
previous = current;
current = (previous >= 4 ? previous - 4 : 0);
} }
// Report an error if no footer marker was found.
if (previous == NULL) {
WARNING ("No stop marker present.");
return DEVICE_STATUS_ERROR;
}
// Move the pointer to the end of the footer.
previous += sizeof (footer);
// Automatically abort when a dive is older than the provided timestamp.
unsigned int timestamp = array_uint32_le (current + 4);
if (device && timestamp <= device->timestamp) {
if (aborted)
*aborted = 1;
return DEVICE_STATUS_SUCCESS;
}
if (callback && !callback (current, previous - current, userdata)) {
if (aborted)
*aborted = 1;
return DEVICE_STATUS_SUCCESS;
}
// Prepare for the next iteration.
previous = current;
// Return the current state.
*premaining = *pprevious = current - data;
} }
// Return the offset to the last dive. // Return the current state.
if (pprevious) *premaining = sizeof (header) - 1;
*pprevious = previous; if (*premaining > *pprevious)
*premaining = *pprevious;
if (aborted) if (aborted)
*aborted = 0; *aborted = 0;
@ -724,6 +723,7 @@ reefnet_sensusultra_device_foreach (device_t *abstract, dive_callback_t callback
} }
// Initialize the state for the incremental parser. // Initialize the state for the incremental parser.
unsigned int remaining = 0;
unsigned int previous = 0; unsigned int previous = 0;
unsigned int nbytes = 0; unsigned int nbytes = 0;
@ -752,12 +752,13 @@ reefnet_sensusultra_device_foreach (device_t *abstract, dive_callback_t callback
} }
// Update the parser state. // Update the parser state.
remaining += REEFNET_SENSUSULTRA_PACKET_SIZE;
previous += REEFNET_SENSUSULTRA_PACKET_SIZE; previous += REEFNET_SENSUSULTRA_PACKET_SIZE;
// Parse the page data. // Parse the page data.
int aborted = 0; int aborted = 0;
rc = reefnet_sensusultra_parse (device, dc_buffer_get_data (buffer), rc = reefnet_sensusultra_parse (device, dc_buffer_get_data (buffer),
REEFNET_SENSUSULTRA_PACKET_SIZE, &previous, &aborted, callback, userdata); &remaining, &previous, &aborted, callback, userdata);
if (rc != DEVICE_STATUS_SUCCESS) { if (rc != DEVICE_STATUS_SUCCESS) {
dc_buffer_free (buffer); dc_buffer_free (buffer);
return rc; return rc;
@ -790,5 +791,8 @@ reefnet_sensusultra_extract_dives (device_t *abstract, const unsigned char data[
if (abstract && !device_is_reefnet_sensusultra (abstract)) if (abstract && !device_is_reefnet_sensusultra (abstract))
return DEVICE_STATUS_TYPE_MISMATCH; return DEVICE_STATUS_TYPE_MISMATCH;
return reefnet_sensusultra_parse (device, data, size, NULL, NULL, callback, userdata); unsigned int remaining = size;
unsigned int previous = size;
return reefnet_sensusultra_parse (device, data, &remaining, &previous, NULL, callback, userdata);
} }