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Lat-lon parsing: allow lon,lat order, and detect order

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Flightplan/route-manager defaults to lon,lat order. Allow the parser
to detect the correct order when NSEW suffixes are provided and 
consistent.
This commit is contained in:
James Turner 2018-06-29 13:28:02 +01:00
parent 609ac93c10
commit d7a413d5e7
3 changed files with 65 additions and 7 deletions
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37
simgear/misc/strutils.cxx
View File

@ -1179,7 +1179,21 @@ bool parseStringAsLatLonValue(const std::string& s, double& degrees)
return true;
}
bool parseStringAsGeod(const std::string& s, SGGeod* result)
namespace {
bool isLatString(const std::string &s)
{
const char lastChar = ::toupper(s.back());
return (lastChar == 'N') || (lastChar == 'S');
}
bool isLonString(const std::string &s)
{
const char lastChar = ::toupper(s.back());
return (lastChar == 'E') || (lastChar == 'W');
}
} // of anonymous namespace
bool parseStringAsGeod(const std::string& s, SGGeod* result, bool assumeLonLatOrder)
{
if (s.empty())
return false;
@ -1189,16 +1203,27 @@ bool parseStringAsGeod(const std::string& s, SGGeod* result)
return false;
}
double lat, lon;
if (!parseStringAsLatLonValue(s.substr(0, commaPos), lat) ||
!parseStringAsLatLonValue(s.substr(commaPos+1), lon))
{
auto termA = simplify(s.substr(0, commaPos)),
termB = simplify(s.substr(commaPos+1));
double valueA, valueB;
if (!parseStringAsLatLonValue(termA, valueA) || !parseStringAsLatLonValue(termB, valueB)) {
return false;
}
if (result) {
*result = SGGeod::fromDeg(lon, lat);
// explicit ordering
if (isLatString(termA) && isLonString(termB)) {
*result = SGGeod::fromDeg(valueB, valueA);
} else if (isLonString(termA) && isLatString(termB)) {
*result = SGGeod::fromDeg(valueA, valueB);
} else {
// implicit ordering
// SGGeod wants longitude, latitude
*result = assumeLonLatOrder ? SGGeod::fromDeg(valueA, valueB)
: SGGeod::fromDeg(valueB, valueA);
}
}
return true;
}

13
simgear/misc/strutils.hxx
View File

@ -367,8 +367,19 @@ namespace simgear {
*
* Supported formats:
* <signed decimal degrees latitude>,<signed decimal degress longitude>
* <unsigned decimal degrees>[NS],<unsigned decimal degrees>[EW]
* <degrees>*<decimal minutes>'[NS],<degrees>*<decimal minutes>'[EW]
*
* Latitude and longitude are parsed seperately so the formats for each
* do not need to agree. Latitude is assumed to precede longitude
* unless assumeLonLatOrder = true
*
* When NSEW characters are used, the order can be swapped and will be
* fixed correctly (longitude then latitude).
*/
bool parseStringAsGeod(const std::string& string, SGGeod* result = nullptr);
bool parseStringAsGeod(const std::string& string,
SGGeod* result = nullptr,
bool assumeLonLatOrder = false);
// enum values here correspond to existing lon-lat format codes inside
// FlightGear (property: /sim/lon-lat-format )

22
simgear/misc/strutils_test.cxx
View File

@ -654,6 +654,28 @@ void test_parseGeod()
SG_VERIFY(strutils::parseStringAsGeod("") == false);
SG_VERIFY(strutils::parseStringAsGeod("aaaaaaaa") == false);
// ordering tests
// normal default order, but explicitly pass as lon,lat
// (should work)
SG_VERIFY(strutils::parseStringAsGeod("3.12345678w, 56.12345678s", &a));
SG_CHECK_EQUAL_EP(a.getLongitudeDeg(), -3.12345678);
SG_CHECK_EQUAL_EP(a.getLatitudeDeg(), -56.12345678);
// different default order
// also some embedded whitespace for fun
SG_VERIFY(strutils::parseStringAsGeod(" -12 34.56,\n-45 27.89 ", &a, true));
SG_CHECK_EQUAL_EP(a.getLongitudeDeg(), -12.576);
SG_CHECK_EQUAL_EP(a.getLatitudeDeg(), -45.464833333);
// differnet default order, but still set explicitly so should
// use the lat,lon order
SG_VERIFY(strutils::parseStringAsGeod("\t40 30'50\"S, 12 34'56\"W ", &a, true));
SG_CHECK_EQUAL_EP(a.getLongitudeDeg(), -12.58222222);
SG_CHECK_EQUAL_EP(a.getLatitudeDeg(), -40.5138888);
}
void test_formatGeod()