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Parse GPX dive coordinates: Qt XML framework

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This replaces the C-code XML parsing with a Qt infrastructure.
QXmlStreamReader is used to parse the GPX file.

It also takes into account comments by @neolit123

Signed-off-by: willemferguson <willemferguson@zoology.up.ac.za>
This commit is contained in:
willemferguson 2020-01-25 10:06:54 +02:00 • committed by Lubomir I. Ivanov
parent 1e14c3f0d3
commit ff18de053f
1 changed files with 48 additions and 107 deletions
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155
core/parse-gpx.cpp
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@ -1,55 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
#include "core/parse-gpx.h"
#include "core/dive.h"
// TODO: instead of manually parsing the XML, we should consider using
// one of the two XML frameworks that we already use elsewhere in
// the code
// Read text from the present position in the file until
// the first 'delim' character is encountered.
static int getSubstring(QFile *file, QString *bufptr, char delim)
{
char c;
bufptr->clear();
do {
if (file->read(&c, 1) <= 0) // EOF
return 1;
if (c == delim) break;
bufptr->append(QChar(c));
} while (c != delim);
return 0;
}
// Find the next occurence of a specified target GPX element in the file,
// characerised by a "<xxx " or "<xxx>" character sequence.
// 'target' specifies the name of the element searched for.
// termc is the ending character of the element name search = '>' or ' '.
static int findXmlElement(QFile *fileptr, QString target, QString *bufptr, char termc)
{
bool match = false;
char c;
char skipdelim = (termc == ' ') ? '>' : ' ';
do { // Skip input until first start new of element (<) is encountered:
if (getSubstring(fileptr, bufptr, '<'))
return 1; // EOF
bufptr->clear();
do { // Read name of following element and store it in buf
if (fileptr->read(&c, 1) <= 0) // EOF encountered
return 1;
if ((c == '>') || (c == ' ')) // found a valid delimiter
break;
bufptr->append(QChar(c));
} while ((c != '>') && (c != ' '));
if (*bufptr == "/trk") // End of GPS track found: return EOF
return 1;
if (c == skipdelim)
continue; // if inappropriate delimiter was found, redo from start
if (*bufptr == target) // Compare xml element name from gpx file with the
match = true; // the target element searched for.
} while (match == false);
return 0;
}
#include <QXmlStreamReader>
// Find the coordinates at the time specified in coords.start_dive
// by searching the gpx file "fileName". Here is a typical trkpt element in GPX:
@ -57,15 +9,15 @@ static int findXmlElement(QFile *fileptr, QString target, QString *bufptr, char
int getCoordsFromGPXFile(struct dive_coords *coords, QString fileName)
{
struct tm tm1;
time_t when = 0;
double lon, lat;
int line = 0;
int64_t time_offset = coords->settingsDiff_offset + coords->timeZone_offset;
time_t trkpt_time = 0;
time_t divetime;
int64_t time_offset = coords->settingsDiff_offset + coords->timeZone_offset;
double lon = 0, lat = 0;
int line = 0;
bool first_line = true;
bool found = false;
bool trkpt_found = false;
divetime = coords->start_dive;
QString buf;
QFile gpxFile;
gpxFile.setFileName(fileName);
if (!gpxFile.open(QIODevice::ReadOnly | QIODevice::Text)) {
@ -86,61 +38,50 @@ int getCoordsFromGPXFile(struct dive_coords *coords, QString fileName)
dmin = time.tm_min;
#endif
do {
line++; // this is the sequence number of the trkpt xml element processed
// Find next trkpt xml element (This function also detects </trk> that signals EOF):
if (findXmlElement(&gpxFile, QString("trkpt"), &buf, ' ')) // This is the normal exit point
break; // for this routine
// == Get coordinates: ==
if (getSubstring(&gpxFile, &buf, '"')) // read up to the end of the "lat=" label
break; // on EOF
if (buf != "lat=") {
fprintf(stderr, "GPX parse error: cannot find latitude (trkpt #%d)\n", line);
return 1;
}
if (getSubstring(&gpxFile, &buf, '"')) // read up to the end of the latitude value
break; // on EOF
lat = buf.toDouble(); // Convert lat to decimal
if (getSubstring(&gpxFile, &buf, ' ')) // Read past space char
break; // on EOF
if (getSubstring(&gpxFile, &buf, '"')) // Read up to end of "lon=" label
break; // on EOF
if (buf != "lon=") {
fprintf(stderr, "GPX parse error: cannot find longitude (trkpt #%d)\n", line);
return 1;
}
if (getSubstring(&gpxFile, &buf, '"')) // get string with longitude
break; // on EOF
lon = buf.toDouble(); // Convert longitude to decimal
// == get time: ==
if (findXmlElement(&gpxFile, QString("time"), &buf, '>')) // Find the <time> element
break; // on EOF
if (getSubstring(&gpxFile, &buf, '<')) // Read the string containing date/time
break; // on EOF
bool ok;
tm1.tm_year = buf.left(4).toInt(&ok, 10); // Extract the different substrings:
tm1.tm_mon = buf.mid(5,2).toInt(&ok,10) - 1;
tm1.tm_mday = buf.mid(8,2).toInt(&ok,10);
tm1.tm_hour = buf.mid(11,2).toInt(&ok,10);
tm1.tm_min = buf.mid(14,2).toInt(&ok,10);
tm1.tm_sec = buf.mid(17,2).toInt(&ok,10);
when = utc_mktime(&tm1) + time_offset;
if (first_line) {
first_line = false;
coords->start_track = when; // Local time of start of GPS track
}
if ((when > divetime && found == false)) { // This GPS local time corresponds to the start time of the dive
coords->lon = lon; // save the coordinates
coords->lat = lat;
found = true;
}
QXmlStreamReader gpxReader(&gpxFile);
while (!gpxReader.atEnd()) {
gpxReader.readNext();
if (gpxReader.isStartElement()) {
if (gpxReader.name() == "trkpt") {
trkpt_found = true;
line++;
foreach (const QXmlStreamAttribute &attr, gpxReader.attributes()) {
if (attr.name().toString() == QLatin1String("lat"))
lat = attr.value().toString().toDouble();
else if (attr.name().toString() == QLatin1String("lon"))
lon = attr.value().toString().toDouble();
}
}
if (gpxReader.name() == "time" && trkpt_found) { // Ignore the <time> element in the GPX file header
QString dateTimeString = gpxReader.readElementText();
bool ok;
tm1.tm_year = dateTimeString.left(4).toInt(&ok, 10); // Extract the date/time components:
tm1.tm_mon = dateTimeString.mid(5,2).toInt(&ok,10) - 1;
tm1.tm_mday = dateTimeString.mid(8,2).toInt(&ok,10);
tm1.tm_hour = dateTimeString.mid(11,2).toInt(&ok,10);
tm1.tm_min = dateTimeString.mid(14,2).toInt(&ok,10);
tm1.tm_sec = dateTimeString.mid(17,2).toInt(&ok,10);
trkpt_time = utc_mktime(&tm1) + time_offset;
if (first_line) {
first_line = false;
coords->start_track = trkpt_time; // Local time of start of GPS track
}
if (trkpt_time >= divetime && found == false) { // This GPS local time corresponds to the start time of the dive
coords->lon = lon; // save the coordinates
coords->lat = lat;
found = true;
}
#ifdef GPSDEBUG
utc_mkdate(when, &time); // print time and coordinates of each of the trkpt elements of the GPX file
fprintf(stderr, " %02d: lat=%f lon=%f timestamp=%ld (%ld) %02d/%02d/%02d %02d:%02d dt=%ld %02d/%02d/%02d %02d:%02d\n", line, lat,
lon, when, time_offset, time.tm_year, time.tm_mon+1, time.tm_mday, time.tm_hour, time.tm_min, divetime, dyr, dmon+1, dday,dhr, dmin );
utc_mkdate(trkpt_time, &time); // print coordinates and time of each trkpt element of the GPX file as well as dive start time
fprintf(stderr, " %02d: lat=%f lon=%f timestamp=%ld (%ld) %02d/%02d/%02d %02d:%02d dt=%ld %02d/%02d/%02d %02d:%02d\n", line, lat,
lon, trkpt_time, time_offset, time.tm_year, time.tm_mon+1, time.tm_mday, time.tm_hour, time.tm_min, divetime, dyr, dmon+1, dday,dhr, dmin);
#endif
} while (true); // This loop executes until EOF causes a break out of the loop
coords->end_track = when; // This is the local time of the end of the GPS track
}
}
} // while !at.End() // This loop executes until EOF causes a break out of the loop
coords->end_track = trkpt_time; // This is the local time of the end of the GPS track
gpxFile.close();
return 0;
}