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Improve error handling when calculating CRCs

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Let the standard library throw if anything goes wrong, and catch that
exception instead of throwing on certain errors.
This commit is contained in:
Oliver Hamlet
2016-12-14 22:22:27 +00:00
parent cf4f7252ec
commit 5d2f40307f
1 changed files with 34 additions and 17 deletions
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src/backend/helpers/helpers.cpp
+34 -17
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@@ -59,29 +59,46 @@ using std::string;
using std::wstring;
namespace loot {
//Calculate the CRC of the given file for comparison purposes.
size_t GetStreamSize(std::istream& stream) {
std::streampos startingPosition = stream.tellg();
stream.seekg(0, std::ios_base::end);
size_t streamSize = stream.tellg();
stream.seekg(startingPosition, std::ios_base::beg);
return streamSize;
}
//Calculate the CRC of the given file for comparison purposes.
uint32_t GetCrc32(const boost::filesystem::path& filename) {
uint32_t chksum = 0;
try {
boost::filesystem::ifstream ifile(filename, std::ios::binary);
BOOST_LOG_TRIVIAL(trace) << "Calculating CRC for: " << filename.string();
boost::filesystem::ifstream ifile(filename, std::ios::binary);
ifile.exceptions(std::ios_base::badbit | std::ios_base::failbit);
static const size_t bufferSize = 8192;
char buffer[bufferSize];
boost::crc_32_type result;
if (ifile) {
static const size_t buffer_size = 8192;
char buffer[buffer_size];
do {
ifile.read(buffer, buffer_size);
result.process_bytes(buffer, ifile.gcount());
} while (ifile);
chksum = result.checksum();
} else
throw std::exception();
} catch (std::exception&) {
size_t bytesLeft = GetStreamSize(ifile);
while (bytesLeft > 0) {
if (bytesLeft > bufferSize)
ifile.read(buffer, bufferSize);
else
ifile.read(buffer, bytesLeft);
result.process_bytes(buffer, ifile.gcount());
bytesLeft -= ifile.gcount();
}
uint32_t checksum = result.checksum();
BOOST_LOG_TRIVIAL(debug) << "CRC32(\"" << filename.string() << "\"): " << std::hex << checksum << std::dec;
return checksum;
} catch (std::exception& e) {
BOOST_LOG_TRIVIAL(error) << "Unable to open \"" << filename.string() << "\" for CRC calculation.";
throw FileAccessError((boost::format(translate("Unable to open \"%1%\" for CRC calculation.")) % filename.string()).str());
throw FileAccessError((boost::format(translate("Unable to open \"%1%\" for CRC calculation: %2%")) % filename.string() % e.what()).str());
}
BOOST_LOG_TRIVIAL(debug) << "CRC32(\"" << filename.string() << "\"): " << std::hex << chksum << std::dec;
return chksum;
}
//Converts an integer to a hex string using BOOST's Spirit.Karma, which is apparently a lot faster than a stringstream conversion...