#862: WKBReader::readHEX: Incorrect use of char_traits<char>::eof()
------------------------+--------------------------
Reporter: goatbar | Owner: geos-devel@…
Type: defect | Status: new
Priority: major | Milestone: 3.6.3
Component: Default | Version: 3.6.2
Severity: Unassigned | Keywords:
------------------------+--------------------------
char_traits<char>::eof() returns an int. It doesn't always work to
compare to a char.
I was seeing invalid 255s thrown.
My sample fix... I add localized vars, added consts, and factored out the
switch statement so it's only in there 1 time.
{{{#!patch
--- a/geos/src/io/WKBReader.cpp 2018-02-28 11:14:06.000000000 -0800
+++ b/geos/src/io/WKBReader.cpp 2018-03-15 14:48:55.000000000 -0700
@@ -74,6 +74,56 @@
return os;
}
+namespace {
+
+unsigned char HexToUChar(int val)
+{
+ switch ( val )
+ {
+ case '0' :
+ return 0;
+ case '1' :
+ return 1;
+ case '2' :
+ return 2;
+ case '3' :
+ return 3;
+ case '4' :
+ return 4;
+ case '5' :
+ return 5;
+ case '6' :
+ return 6;
+ case '7' :
+ return 7;
+ case '8' :
+ return 8;
+ case '9' :
+ return 9;
+ case 'A' :
+ case 'a' :
+ return 10;
+ case 'B' :
+ case 'b' :
+ return 11;
+ case 'C' :
+ case 'c' :
+ return 12;
+ case 'D' :
+ case 'd' :
+ return 13;
+ case 'E' :
+ case 'e' :
+ return 14;
+ case 'F' :
+ case 'f' :
+ return 15;
+ default:
+ throw ParseException("Invalid HEX char");
+ }
+}
+
+} // namespace
Geometry *
WKBReader::readHEX(istream &is)
@@ -81,137 +131,24 @@
// setup input/output stream
stringstream os(ios_base::binary|ios_base::in|ios_base::out);
- unsigned char result_high, result_low, value;
- char high, low;
-
- while( (high = static_cast<char>(is.get())) !=
char_traits<char>::eof() )
+ while( true )
{
- // geth the low part of the byte
- low = static_cast<char>(is.get());
- if ( low == char_traits<char>::eof() )
- throw ParseException("Premature end of HEX string");
-
- switch (high)
- {
- case '0' :
- result_high = 0;
- break;
- case '1' :
- result_high = 1;
- break;
- case '2' :
- result_high = 2;
- break;
- case '3' :
- result_high = 3;
- break;
- case '4' :
- result_high = 4;
- break;
- case '5' :
- result_high = 5;
- break;
- case '6' :
- result_high = 6;
- break;
- case '7' :
- result_high = 7;
- break;
- case '8' :
- result_high = 8;
- break;
- case '9' :
- result_high = 9;
- break;
- case 'A' :
- case 'a' :
- result_high = 10;
- break;
- case 'B' :
- case 'b' :
- result_high = 11;
- break;
- case 'C' :
- case 'c' :
- result_high = 12;
- break;
- case 'D' :
- case 'd' :
- result_high = 13;
- break;
- case 'E' :
- case 'e' :
- result_high = 14;
- break;
- case 'F' :
- case 'f' :
- result_high = 15;
- break;
- default:
- throw ParseException("Invalid HEX char");
- }
-
- switch (low)
- {
- case '0' :
- result_low = 0;
- break;
- case '1' :
- result_low = 1;
- break;
- case '2' :
- result_low = 2;
- break;
- case '3' :
- result_low = 3;
- break;
- case '4' :
- result_low = 4;
- break;
- case '5' :
- result_low = 5;
- break;
- case '6' :
- result_low = 6;
- break;
- case '7' :
- result_low = 7;
- break;
- case '8' :
- result_low = 8;
- break;
- case '9' :
- result_low = 9;
- break;
- case 'A' :
- case 'a' :
- result_low = 10;
- break;
- case 'B' :
- case 'b' :
- result_low = 11;
- break;
- case 'C' :
- case 'c' :
- result_low = 12;
- break;
- case 'D' :
- case 'd' :
- result_low = 13;
- break;
- case 'E' :
- case 'e' :
- result_low = 14;
- break;
- case 'F' :
- case 'f' :
- result_low = 15;
- break;
- default:
- throw ParseException("Invalid HEX char");
- }
+ const int input_high = is.get();
+ if (input_high == char_traits<char>::eof())
+ break;
+
+ const int input_low = is.get();
+ if (input_low == char_traits<char>::eof())
+ throw ParseException("Premature end of HEX
string");
+
+ const char high = static_cast<char>(input_high);
+ const char low = static_cast<char>(input_low);
+
+ const unsigned char result_high = HexToUChar(high);
+ const unsigned char result_low = HexToUChar(low);
- value = static_cast<char>((result_high<<4) + result_low);
+ const unsigned char value =
+ static_cast<char>((result_high<<4) + result_low);
#if DEBUG_HEX_READER
cout<<"HEX "<<high<<low<<" -> DEC "<<(int)value<<endl;
}}}
--
Ticket URL: <https://trac.osgeo.org/geos/ticket/862>
GEOS <http://trac.osgeo.org/geos>
GEOS (Geometry Engine - Open Source) is a C++ port of the Java Topology Suite
(JTS).
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