mirror of
https://github.com/qpdf/qpdf.git
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478c05fcab
If NO_GET_ENVIRONMENT is #defined at compile time on Windows, do not call GetEnvironmentVariable. QUtil::get_env will always return false. This option is not available through configure. This was added to support a specific user's requirements to avoid calling GetEnvironmentVariable from the Windows API. Nothing in qpdf outside the test coverage system in qtest relies on QUtil::get_env.
498 lines
11 KiB
C++
498 lines
11 KiB
C++
// Include qpdf-config.h first so off_t is guaranteed to have the right size.
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#include <qpdf/qpdf-config.h>
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#include <qpdf/QUtil.hh>
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#include <qpdf/PointerHolder.hh>
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#include <cmath>
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#include <iomanip>
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#include <sstream>
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#include <stdexcept>
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#include <stdio.h>
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#include <errno.h>
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#include <ctype.h>
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#include <stdlib.h>
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#include <string.h>
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#include <fcntl.h>
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#ifdef _WIN32
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#include <Windows.h>
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#include <direct.h>
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#include <io.h>
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#include <Wincrypt.h>
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#else
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#include <unistd.h>
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#endif
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std::string
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QUtil::int_to_string(long long num, int length)
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{
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return int_to_string_base(num, 10, length);
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}
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std::string
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QUtil::int_to_string_base(long long num, int base, int length)
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{
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// Backward compatibility -- int_to_string, which calls this
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// function, used to use sprintf with %0*d, so we interpret length
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// such that a negative value appends spaces and a positive value
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// prepends zeroes.
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if (! ((base == 8) || (base == 10) || (base == 16)))
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{
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throw std::logic_error(
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"int_to_string_base called with unsupported base");
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}
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std::ostringstream buf;
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buf << std::setbase(base) << std::nouppercase << num;
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std::string result;
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if ((length > 0) &&
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(buf.str().length() < static_cast<size_t>(length)))
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{
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result.append(length - buf.str().length(), '0');
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}
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result += buf.str();
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if ((length < 0) && (buf.str().length() < static_cast<size_t>(-length)))
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{
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result.append(-length - buf.str().length(), ' ');
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}
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return result;
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}
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std::string
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QUtil::double_to_string(double num, int decimal_places)
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{
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// Backward compatibility -- this code used to use sprintf and
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// treated decimal_places <= 0 to mean to use the default, which
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// was six decimal places. Also sprintf with %*.f interprets the
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// length as fixed point rather than significant figures.
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if (decimal_places <= 0)
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{
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decimal_places = 6;
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}
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std::ostringstream buf;
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buf << std::setprecision(decimal_places) << std::fixed << num;
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return buf.str();
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}
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long long
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QUtil::string_to_ll(char const* str)
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{
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#ifdef _MSC_VER
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return _strtoi64(str, 0, 10);
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#else
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return strtoll(str, 0, 10);
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#endif
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}
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unsigned char*
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QUtil::unsigned_char_pointer(std::string const& str)
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{
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return reinterpret_cast<unsigned char*>(const_cast<char*>(str.c_str()));
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}
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unsigned char*
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QUtil::unsigned_char_pointer(char const* str)
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{
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return reinterpret_cast<unsigned char*>(const_cast<char*>(str));
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}
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void
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QUtil::throw_system_error(std::string const& description)
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{
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#ifdef _MSC_VER
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// "94" is mentioned in the MSVC docs, but it's still safe if the
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// message is longer. strerror_s is a templated function that
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// knows the size of buf and truncates.
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char buf[94];
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if (strerror_s(buf, errno) != 0)
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{
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throw std::runtime_error(description + ": failed with an unknown error");
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}
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else
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{
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throw std::runtime_error(description + ": " + buf);
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}
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#else
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throw std::runtime_error(description + ": " + strerror(errno));
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#endif
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}
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int
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QUtil::os_wrapper(std::string const& description, int status)
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{
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if (status == -1)
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{
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throw_system_error(description);
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}
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return status;
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}
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FILE*
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QUtil::safe_fopen(char const* filename, char const* mode)
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{
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FILE* f = 0;
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#ifdef _MSC_VER
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errno_t err = fopen_s(&f, filename, mode);
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if (err != 0)
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{
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errno = err;
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throw_system_error(std::string("open ") + filename);
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}
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#else
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f = fopen_wrapper(std::string("open ") + filename, fopen(filename, mode));
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#endif
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return f;
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}
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FILE*
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QUtil::fopen_wrapper(std::string const& description, FILE* f)
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{
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if (f == 0)
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{
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throw_system_error(description);
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}
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return f;
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}
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int
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QUtil::seek(FILE* stream, qpdf_offset_t offset, int whence)
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{
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#if HAVE_FSEEKO
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return fseeko(stream, static_cast<off_t>(offset), whence);
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#elif HAVE_FSEEKO64
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return fseeko64(stream, offset, whence);
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#else
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# ifdef _MSC_VER
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return _fseeki64(stream, offset, whence);
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# else
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return fseek(stream, static_cast<long>(offset), whence);
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# endif
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#endif
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}
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qpdf_offset_t
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QUtil::tell(FILE* stream)
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{
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#if HAVE_FSEEKO
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return static_cast<qpdf_offset_t>(ftello(stream));
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#elif HAVE_FSEEKO64
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return static_cast<qpdf_offset_t>(ftello64(stream));
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#else
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# ifdef _MSC_VER
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return _ftelli64(stream);
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# else
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return static_cast<qpdf_offset_t>(ftell(stream));
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# endif
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#endif
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}
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char*
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QUtil::copy_string(std::string const& str)
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{
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char* result = new char[str.length() + 1];
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// Use memcpy in case string contains nulls
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result[str.length()] = '\0';
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memcpy(result, str.c_str(), str.length());
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return result;
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}
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std::string
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QUtil::hex_encode(std::string const& input)
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{
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std::string result;
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for (unsigned int i = 0; i < input.length(); ++i)
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{
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result += QUtil::int_to_string_base(
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static_cast<int>(static_cast<unsigned char>(input.at(i))), 16, 2);
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}
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return result;
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}
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void
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QUtil::binary_stdout()
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{
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#ifdef _WIN32
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_setmode(_fileno(stdout), _O_BINARY);
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#endif
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}
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void
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QUtil::binary_stdin()
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{
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#ifdef _WIN32
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_setmode(_fileno(stdin), _O_BINARY);
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#endif
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}
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void
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QUtil::setLineBuf(FILE* f)
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{
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#ifndef _WIN32
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setvbuf(f, reinterpret_cast<char *>(NULL), _IOLBF, 0);
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#endif
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}
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char*
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QUtil::getWhoami(char* argv0)
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{
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#ifdef _WIN32
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char pathsep = '\\';
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#else
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char pathsep = '/';
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#endif
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char* whoami = 0;
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if ((whoami = strrchr(argv0, pathsep)) == NULL)
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{
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whoami = argv0;
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}
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else
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{
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++whoami;
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}
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#ifdef _WIN32
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if ((strlen(whoami) > 4) &&
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(strcmp(whoami + strlen(whoami) - 4, ".exe") == 0))
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{
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whoami[strlen(whoami) - 4] = '\0';
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}
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#endif
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return whoami;
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}
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bool
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QUtil::get_env(std::string const& var, std::string* value)
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{
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// This was basically ripped out of wxWindows.
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#ifdef _WIN32
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# ifdef NO_GET_ENVIRONMENT
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return false;
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# else
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// first get the size of the buffer
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DWORD len = ::GetEnvironmentVariable(var.c_str(), NULL, 0);
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if (len == 0)
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{
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// this means that there is no such variable
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return false;
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}
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if (value)
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{
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char* t = new char[len + 1];
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::GetEnvironmentVariable(var.c_str(), t, len);
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*value = t;
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delete [] t;
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}
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return true;
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# endif
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#else
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char* p = getenv(var.c_str());
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if (p == 0)
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{
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return false;
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}
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if (value)
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{
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*value = p;
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}
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return true;
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#endif
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}
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time_t
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QUtil::get_current_time()
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{
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#ifdef _WIN32
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// The procedure to get local time at this resolution comes from
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// the Microsoft documentation. It says to convert a SYSTEMTIME
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// to a FILETIME, and to copy the FILETIME to a ULARGE_INTEGER.
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// The resulting number is the number of 100-nanosecond intervals
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// between January 1, 1601 and now. POSIX threads wants a time
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// based on January 1, 1970, so we adjust by subtracting the
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// number of seconds in that time period from the result we get
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// here.
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SYSTEMTIME sysnow;
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GetSystemTime(&sysnow);
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FILETIME filenow;
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SystemTimeToFileTime(&sysnow, &filenow);
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ULARGE_INTEGER uinow;
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uinow.LowPart = filenow.dwLowDateTime;
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uinow.HighPart = filenow.dwHighDateTime;
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ULONGLONG now = uinow.QuadPart;
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return ((now / 10000000LL) - 11644473600LL);
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#else
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return time(0);
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#endif
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}
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std::string
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QUtil::toUTF8(unsigned long uval)
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{
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std::string result;
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// A UTF-8 encoding of a Unicode value is a single byte for
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// Unicode values <= 127. For larger values, the first byte of
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// the UTF-8 encoding has '1' as each of its n highest bits and
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// '0' for its (n+1)th highest bit where n is the total number of
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// bytes required. Subsequent bytes start with '10' and have the
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// remaining 6 bits free for encoding. For example, an 11-bit
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// Unicode value can be stored in two bytes where the first is
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// 110zzzzz, the second is 10zzzzzz, and the z's represent the
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// remaining bits.
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if (uval > 0x7fffffff)
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{
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throw std::runtime_error("bounds error in QUtil::toUTF8");
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}
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else if (uval < 128)
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{
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result += static_cast<char>(uval);
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}
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else
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{
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unsigned char bytes[7];
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bytes[6] = '\0';
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unsigned char* cur_byte = &bytes[5];
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// maximum value that will fit in the current number of bytes
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unsigned char maxval = 0x3f; // six bits
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while (uval > maxval)
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{
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// Assign low six bits plus 10000000 to lowest unused
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// byte position, then shift
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*cur_byte = static_cast<unsigned char>(0x80 + (uval & 0x3f));
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uval >>= 6;
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// Maximum that will fit in high byte now shrinks by one bit
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maxval >>= 1;
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// Slide to the left one byte
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if (cur_byte <= bytes)
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{
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throw std::logic_error("QUtil::toUTF8: overflow error");
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}
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--cur_byte;
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}
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// If maxval is k bits long, the high (7 - k) bits of the
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// resulting byte must be high.
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*cur_byte = static_cast<unsigned char>(
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(0xff - (1 + (maxval << 1))) + uval);
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result += reinterpret_cast<char*>(cur_byte);
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}
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return result;
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}
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#ifdef USE_INSECURE_RANDOM
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long
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QUtil::random()
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{
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static bool seeded_random = false;
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if (! seeded_random)
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{
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// Seed the random number generator with something simple, but
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// just to be interesting, don't use the unmodified current
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// time. It would be better if this were a more secure seed.
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QUtil::srandom(QUtil::get_current_time() ^ 0xcccc);
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seeded_random = true;
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}
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# ifdef HAVE_RANDOM
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return ::random();
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# else
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return rand();
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# endif
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}
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void
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QUtil::initializeWithRandomBytes(unsigned char* data, size_t len)
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{
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for (size_t i = 0; i < len; ++i)
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{
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data[i] = static_cast<unsigned char>((QUtil::random() & 0xff0) >> 4);
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}
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}
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#else
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long
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QUtil::random()
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{
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long result = 0L;
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initializeWithRandomBytes(
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reinterpret_cast<unsigned char*>(&result),
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sizeof(result));
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return result;
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}
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#ifdef _WIN32
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class WindowsCryptProvider
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{
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public:
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WindowsCryptProvider()
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{
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if (! CryptAcquireContext(&crypt_prov, NULL, NULL, PROV_RSA_FULL, 0))
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{
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throw std::runtime_error("unable to acquire crypt context");
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}
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}
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~WindowsCryptProvider()
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{
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// Ignore error
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CryptReleaseContext(crypt_prov, 0);
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}
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HCRYPTPROV crypt_prov;
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};
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#endif
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void
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QUtil::initializeWithRandomBytes(unsigned char* data, size_t len)
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{
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#if defined(_WIN32)
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// Optimization: make the WindowsCryptProvider static as long as
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// it can be done in a thread-safe fashion.
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WindowsCryptProvider c;
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if (! CryptGenRandom(c.crypt_prov, len, reinterpret_cast<BYTE*>(data)))
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{
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throw std::runtime_error("unable to generate secure random data");
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}
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#elif defined(RANDOM_DEVICE)
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// Optimization: wrap the file open and close in a class so that
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// the file is closed in a destructor, then make this static to
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// keep the file handle open. Only do this if it can be done in a
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// thread-safe fashion.
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FILE* f = QUtil::safe_fopen(RANDOM_DEVICE, "rb");
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size_t fr = fread(data, 1, len, f);
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fclose(f);
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if (fr != len)
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{
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throw std::runtime_error(
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"unable to read " +
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QUtil::int_to_string(len) +
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" bytes from " + std::string(RANDOM_DEVICE));
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}
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#else
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# error "Don't know how to generate secure random numbers on this platform. See random number generation in the top-level README"
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#endif
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}
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#endif
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void
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QUtil::srandom(unsigned int seed)
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{
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#ifdef HAVE_RANDOM
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::srandom(seed);
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#else
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srand(seed);
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#endif
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}
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