summaryrefslogtreecommitdiff
path: root/zen/dst_hack.cpp
diff options
context:
space:
mode:
authorDaniel Wilhelm <daniel@wili.li>2015-10-02 14:53:20 +0200
committerDaniel Wilhelm <daniel@wili.li>2015-10-02 14:53:20 +0200
commit94db751716dd2851f99b5c4c2981da1d1f4780f8 (patch)
treee4ffc9f5ae2b2873f267a6e5d3d2092c8aad49a7 /zen/dst_hack.cpp
parent6.10 (diff)
downloadFreeFileSync-94db751716dd2851f99b5c4c2981da1d1f4780f8.tar.gz
FreeFileSync-94db751716dd2851f99b5c4c2981da1d1f4780f8.tar.bz2
FreeFileSync-94db751716dd2851f99b5c4c2981da1d1f4780f8.zip
6.11
Diffstat (limited to 'zen/dst_hack.cpp')
-rw-r--r--zen/dst_hack.cpp368
1 files changed, 0 insertions, 368 deletions
diff --git a/zen/dst_hack.cpp b/zen/dst_hack.cpp
deleted file mode 100644
index b38f73b4..00000000
--- a/zen/dst_hack.cpp
+++ /dev/null
@@ -1,368 +0,0 @@
-#include "dst_hack.h"
-#include <bitset>
-#include "basic_math.h"
-#include "long_path_prefix.h"
-#include "utf.h"
-#include "assert_static.h"
-#include "int64.h"
-#include "file_error.h"
-#include "dll.h"
-
-using namespace zen;
-
-
-namespace
-{
-//fast ::GetVolumePathName() clone: let's hope it's not too simple (doesn't honor mount points)
-Zstring getVolumeName(const Zstring& filepath)
-{
- //this call is expensive: ~1.5 ms!
- // if (!::GetVolumePathName(filepath.c_str(), //__in LPCTSTR lpszFileName,
- // fsName, //__out LPTSTR lpszVolumePathName,
- // BUFFER_SIZE)) //__in DWORD cchBufferLength
- // ...
- // Zstring volumePath = appendSeparator(fsName);
-
- const Zstring nameFmt = appendSeparator(removeLongPathPrefix(filepath)); //throw()
-
- if (startsWith(nameFmt, Zstr("\\\\"))) //UNC path: "\\ComputerName\SharedFolder\"
- {
- size_t nameSize = nameFmt.size();
- const size_t posFirstSlash = nameFmt.find(Zstr("\\"), 2);
- if (posFirstSlash != Zstring::npos)
- {
- nameSize = posFirstSlash + 1;
- const size_t posSecondSlash = nameFmt.find(Zstr("\\"), posFirstSlash + 1);
- if (posSecondSlash != Zstring::npos)
- nameSize = posSecondSlash + 1;
- }
- return Zstring(nameFmt.c_str(), nameSize); //include trailing backslash!
- }
- else //local path: "C:\Folder\"
- {
- const size_t pos = nameFmt.find(Zstr(":\\"));
- if (pos == 1) //expect single letter volume
- return Zstring(nameFmt.c_str(), 3);
- }
-
- return Zstring();
-}
-}
-
-
-bool dst::isFatDrive(const Zstring& filepath) //throw()
-{
- const Zstring volumePath = getVolumeName(filepath);
- if (volumePath.empty())
- return false;
-
- const DWORD bufferSize = MAX_PATH + 1;
- wchar_t fsName[bufferSize] = {};
-
- //suprisingly fast: ca. 0.03 ms per call!
- if (!::GetVolumeInformation(appendSeparator(volumePath).c_str(), //__in_opt LPCTSTR lpRootPathName,
- nullptr, //__out LPTSTR lpVolumeNameBuffer,
- 0, //__in DWORD nVolumeNameSize,
- nullptr, //__out_opt LPDWORD lpVolumeSerialNumber,
- nullptr, //__out_opt LPDWORD lpMaximumComponentLength,
- nullptr, //__out_opt LPDWORD lpFileSystemFlags,
- fsName, //__out LPTSTR lpFileSystemNameBuffer,
- bufferSize)) //__in DWORD nFileSystemNameSize
- {
- assert(false); //shouldn't happen
- return false;
- }
- //DST hack seems to be working equally well for FAT and FAT32 (in particular creation time has 10^-2 s precision as advertised)
- return fsName == Zstring(L"FAT") ||
- fsName == Zstring(L"FAT32");
-}
-
-
-/*
-bool dst::isFatDrive(HANDLE hFile) //throw()
-{
-Requires Windows Vista!
- //dynamically load windows API function
- typedef BOOL (WINAPI* GetVolumeInformationByHandleWFunc)(HANDLE hFile,
- LPWSTR lpVolumeNameBuffer,
- DWORD nVolumeNameSize,
- LPDWORD lpVolumeSerialNumber,
- LPDWORD lpMaximumComponentLength,
- LPDWORD lpFileSystemFlags,
- LPWSTR lpFileSystemNameBuffer,
- DWORD nFileSystemNameSize);
-
- const SysDllFun<GetVolumeInformationByHandleWFunc> getVolumeInformationByHandle(L"kernel32.dll", "GetVolumeInformationByHandleW");
- if (!getVolumeInformationByHandle)
- {
- assert(false);
- return false;
- }
-
- const size_t BUFFER_SIZE = MAX_PATH + 1;
- wchar_t fsName[BUFFER_SIZE];
-
- if (!getVolumeInformationByHandle(hFile, //__in HANDLE hFile,
- nullptr, //__out LPTSTR lpVolumeNameBuffer,
- 0, //__in DWORD nVolumeNameSize,
- nullptr, //__out_opt LPDWORD lpVolumeSerialNumber,
- nullptr, //__out_opt LPDWORD lpMaximumComponentLength,
- nullptr, //__out_opt LPDWORD lpFileSystemFlags,
- fsName, //__out LPTSTR lpFileSystemNameBuffer,
- BUFFER_SIZE)) //__in DWORD nFileSystemNameSize
- {
- assert(false); //shouldn't happen
- return false;
- }
- //DST hack seems to be working equally well for FAT and FAT32 (in particular creation time has 10^-2 s precision as advertised)
- return fsName == Zstring(L"FAT") ||
- fsName == Zstring(L"FAT32");
-}
-*/
-
-
-namespace
-{
-//convert std::uint64_t and std::int64_t to FILETIME
-inline
-FILETIME toFiletime(std::uint64_t number)
-{
- ULARGE_INTEGER cvt = {};
- cvt.QuadPart = number;
-
- const FILETIME output = { cvt.LowPart, cvt.HighPart };
- return output;
-}
-
-inline
-FILETIME toFiletime(std::int64_t number)
-{
- return toFiletime(static_cast<std::uint64_t>(number));
-}
-
-inline
-std::uint64_t toUInt64(const FILETIME& fileTime)
-{
- return get64BitUInt(fileTime.dwLowDateTime, fileTime.dwHighDateTime);
-}
-
-
-inline
-std::int64_t toInt64(const FILETIME& fileTime)
-{
- return get64BitUInt(fileTime.dwLowDateTime, fileTime.dwHighDateTime); //convert unsigned to signed in return
-}
-
-
-inline
-FILETIME utcToLocal(const FILETIME& utcTime) //throw std::runtime_error
-{
- //treat binary local time representation (which is invariant under DST time zone shift) as logical UTC:
- FILETIME localTime = {};
- if (!::FileTimeToLocalFileTime(
- &utcTime, //__in const FILETIME *lpFileTime,
- &localTime)) //__out LPFILETIME lpLocalFileTime
- {
- const DWORD lastError = ::GetLastError(); //copy before directly or indirectly making other system calls!
- throw std::runtime_error(utfCvrtTo<std::string>(_("Conversion error:") + L" FILETIME -> local FILETIME: " + L"(" +
- L"High: " + numberTo<std::wstring>(utcTime.dwHighDateTime) + L" " +
- L"Low: " + numberTo<std::wstring>(utcTime.dwLowDateTime) + L") " + L"\n\n" + formatSystemError(L"FileTimeToLocalFileTime", lastError)));
- }
- return localTime;
-}
-
-
-inline
-FILETIME localToUtc(const FILETIME& localTime) //throw std::runtime_error
-{
- //treat binary local time representation (which is invariant under DST time zone shift) as logical UTC:
- FILETIME utcTime = {};
- if (!::LocalFileTimeToFileTime(
- &localTime, //__in const FILETIME *lpLocalFileTime,
- &utcTime)) //__out LPFILETIME lpFileTime
- {
- const DWORD lastError = ::GetLastError(); //copy before directly or indirectly making other system calls!
- throw std::runtime_error(utfCvrtTo<std::string>(_("Conversion error:") + L" local FILETIME -> FILETIME: " + L"(" +
- L"High: " + numberTo<std::wstring>(localTime.dwHighDateTime) + L" " +
- L"Low: " + numberTo<std::wstring>(localTime.dwLowDateTime) + L") " + L"\n\n" + formatSystemError(L"LocalFileTimeToFileTime", lastError)));
- }
- return utcTime;
-}
-
-
-//struct FILETIME {DWORD dwLowDateTime; DWORD dwHighDateTime;};
-const FILETIME FAT_MIN_TIME = { 13374976, 27846544 }; //1980 \ both are valid max/min FAT dates for 2 second precision
-const FILETIME FAT_MAX_TIME = { 14487552, 37251238 }; //2107 /
-
-//http://en.wikipedia.org/wiki/File_Allocation_Table
-const size_t PRECISION_WRITE_TIME = 20000000; //number of 100 ns per step -> 2 s
-const size_t PRECISION_CREATE_TIME = 100000; // -> 1/100 s
-
-/*
-Number of bits of information in create time: ln_2((FAT_MAX_TIME - FAT_MIN_TIME) / PRECISION_CREATE_TIME) = 38.55534023
-Number of bits of information in write time: 30.91148404
-*/
-//total size available to store data:
-const size_t CREATE_TIME_INFO_BITS = 38;
-// I. indicator that offset in II) is present
-const size_t INDICATOR_EXISTING_BITS = 1;
-// II. local<->UTC time offset
-const size_t UTC_LOCAL_OFFSET_BITS = 7;
-// III. indicator that offset in II) corresponds to current local write time (this could be a hash of the write time)
-const size_t WRITE_TIME_HASH_BITS = CREATE_TIME_INFO_BITS - INDICATOR_EXISTING_BITS - UTC_LOCAL_OFFSET_BITS;
-
-
-template <size_t precision> inline
-FILETIME encodeRawInformation(std::uint64_t rawInfo)
-{
- rawInfo *= precision;
- rawInfo += toUInt64(FAT_MIN_TIME);
-
- assert(rawInfo <= toUInt64(FAT_MAX_TIME));
- return toFiletime(rawInfo);
-}
-
-
-template <size_t precision> inline
-std::uint64_t extractRawInformation(const FILETIME& createTime)
-{
- assert(toUInt64(FAT_MIN_TIME) <= toUInt64(createTime));
- assert(toUInt64(createTime) <= toUInt64(FAT_MAX_TIME));
-
- //FAT create time ranges from 1980 - 2107 (2^7 years) with 1/100 seconds precision
- std::uint64_t rawInfo = toUInt64(createTime);
-
- rawInfo -= toUInt64(FAT_MIN_TIME);
- rawInfo /= precision; //reduce precision (FILETIME has unit 10^-7 s)
-
- assert(toUInt64(encodeRawInformation<precision>(rawInfo)) == toUInt64(createTime)); //must be reversible
- return rawInfo;
-}
-
-
-//convert write time to it's minimal representation (no restriction to FAT range "1980 - 2107")
-inline
-std::uint64_t extractRawWriteTime(const FILETIME& writeTime)
-{
- std::uint64_t rawInfo = toUInt64(writeTime);
- assert(rawInfo % PRECISION_WRITE_TIME == 0U);
- rawInfo /= PRECISION_WRITE_TIME; //reduce precision (FILETIME has unit 10^-7 s)
- return rawInfo;
-}
-
-
-//files with different resolution than 2 seconds are rounded up when written to FAT
-inline
-FILETIME roundToFatWriteTime(const FILETIME& writeTime)
-{
- std::uint64_t rawData = toUInt64(writeTime);
-
- if (rawData % PRECISION_WRITE_TIME != 0U)
- rawData += PRECISION_WRITE_TIME;
-
- rawData /= PRECISION_WRITE_TIME;
- rawData *= PRECISION_WRITE_TIME;
- return toFiletime(rawData);
-}
-
-
-//get 7-bit value representing time shift in number of quarter-hours
-std::bitset<UTC_LOCAL_OFFSET_BITS> getUtcLocalShift()
-{
- FILETIME utcTime = FAT_MIN_TIME;
- utcTime.dwHighDateTime += 5000000; //some arbitrary valid time
-
- const FILETIME localTime = utcToLocal(utcTime);
-
- const int timeShiftSec = static_cast<int>((toInt64(localTime) - toInt64(utcTime)) / 10000000); //time shift in seconds
-
- const int timeShiftQuarter = timeShiftSec / (60 * 15); //time shift in quarter-hours
-
- const int absValue = numeric::abs(timeShiftQuarter); //MSVC C++0x bug: std::bitset<>(unsigned long) is ambiguous
-
- if (std::bitset < UTC_LOCAL_OFFSET_BITS - 1 > (absValue).to_ulong() != static_cast<unsigned long>(absValue) || //time shifts that big shouldn't be possible!
- timeShiftSec % (60 * 15) != 0) //all known time shift have at least 15 minute granularity!
- {
- const std::wstring errorMsg = _("Conversion error:") + L" Unexpected UTC <-> local time shift: " + L"(" + numberTo<std::wstring>(timeShiftSec) + L")";
- throw std::runtime_error(utfCvrtTo<std::string>(errorMsg));
- }
-
- std::bitset<UTC_LOCAL_OFFSET_BITS> output(absValue);
- output[UTC_LOCAL_OFFSET_BITS - 1] = timeShiftQuarter < 0; //sign bit
- return output;
-}
-
-
-//get time-zone shift in seconds
-inline
-int convertUtcLocalShift(std::bitset<UTC_LOCAL_OFFSET_BITS> rawShift)
-{
- const bool hasSign = rawShift[UTC_LOCAL_OFFSET_BITS - 1];
- rawShift[UTC_LOCAL_OFFSET_BITS - 1] = false;
-
- assert_static(UTC_LOCAL_OFFSET_BITS <= sizeof(unsigned long) * 8);
- return hasSign ?
- static_cast<int>(rawShift.to_ulong()) * 15 * 60 * -1 :
- static_cast<int>(rawShift.to_ulong()) * 15 * 60;
-}
-}
-
-
-bool dst::fatHasUtcEncoded(const RawTime& rawTime) //"createTimeRaw" as retrieved by ::FindFirstFile() and ::GetFileAttributesEx(); throw std::runtime_error
-{
- if (toUInt64(rawTime.createTimeRaw) < toUInt64(FAT_MIN_TIME) ||
- toUInt64(FAT_MAX_TIME) < toUInt64(rawTime.createTimeRaw))
- {
- assert(false); //shouldn't be possible according to FAT specification
- return false;
- }
-
- const std::uint64_t rawInfo = extractRawInformation<PRECISION_CREATE_TIME>(utcToLocal(rawTime.createTimeRaw));
-
- assert_static(WRITE_TIME_HASH_BITS == 30);
- return (extractRawWriteTime(utcToLocal(rawTime.writeTimeRaw)) & 0x3FFFFFFFU) == (rawInfo & 0x3FFFFFFFU) && //ensure write time wasn't changed externally
- rawInfo >> (CREATE_TIME_INFO_BITS - INDICATOR_EXISTING_BITS) == 1U; //extended data available
-}
-
-
-dst::RawTime dst::fatEncodeUtcTime(const FILETIME& writeTimeRealUtc) //throw std::runtime_error
-{
- const FILETIME fatWriteTimeUtc = roundToFatWriteTime(writeTimeRealUtc); //writeTimeRealUtc may have incompatible precision (NTFS)
-
- //create time lets us store 40 bit of information
-
- //indicator that utc time is encoded -> hopefully results in a date long way in the future; but even if this bit is accidentally set, we still have the hash!
- std::uint64_t data = 1U;
-
- const std::bitset<UTC_LOCAL_OFFSET_BITS> utcShift = getUtcLocalShift();
- data <<= UTC_LOCAL_OFFSET_BITS;
- data |= utcShift.to_ulong();
-
- data <<= WRITE_TIME_HASH_BITS;
- data |= extractRawWriteTime(utcToLocal(fatWriteTimeUtc)) & 0x3FFFFFFFU; //trim to last 30 bit of information
- assert_static(WRITE_TIME_HASH_BITS == 30);
-
- const FILETIME encodedData = localToUtc(encodeRawInformation<PRECISION_CREATE_TIME>(data)); //localToUtc: make sure data is physically saved as FAT local time
- assert(toUInt64(FAT_MIN_TIME) <= toUInt64(encodedData));
- assert(toUInt64(encodedData) <= toUInt64(FAT_MAX_TIME));
-
- return RawTime(encodedData, fatWriteTimeUtc); //keep compatible with other applications, at least until DST shift actually occurs
-}
-
-
-FILETIME dst::fatDecodeUtcTime(const RawTime& rawTime) //return real UTC time; throw (std::runtime_error)
-{
- if (!fatHasUtcEncoded(rawTime))
- return rawTime.writeTimeRaw;
-
- const std::uint64_t rawInfo = extractRawInformation<PRECISION_CREATE_TIME>(utcToLocal(rawTime.createTimeRaw));
-
- const std::bitset<UTC_LOCAL_OFFSET_BITS> rawShift(static_cast<int>((rawInfo >> WRITE_TIME_HASH_BITS) & 0x7FU)); //static_cast<int>: a shame MSC... "unsigned long long" should be supported instead!
- assert_static(UTC_LOCAL_OFFSET_BITS == 7);
-
- const std::int64_t timeShiftSec = convertUtcLocalShift(rawShift);
- const FILETIME writeTimeLocal = utcToLocal(rawTime.writeTimeRaw);
-
- const std::int64_t realUTC = toInt64(writeTimeLocal) - timeShiftSec * 10000000;
- return toFiletime(realUTC);
-}
bgstack15