XrdOucCRC Class Reference

#include <XrdOucCRC.hh>

Collaboration diagram for XrdOucCRC:

Public Member Functions
	XrdOucCRC ()
	~XrdOucCRC ()

Static Public Member Functions
static void	Calc32C (const void *data, size_t count, uint32_t *csval)
static uint32_t	Calc32C (const void *data, size_t count, uint32_t prevcs=0)
static uint32_t	Combine32C (uint32_t Cksum1, uint32_t Cksum2, int DLen)
static uint32_t	CRC32 (const unsigned char *data, int count)
static bool	Ver32C (const void *data, size_t count, const uint32_t *csval, bool *valok)
static int	Ver32C (const void *data, size_t count, const uint32_t *csval, uint32_t &valcs)
static bool	Ver32C (const void *data, size_t count, const uint32_t *csval, uint32_t *valcs)
static bool	Ver32C (const void *data, size_t count, const uint32_t csval, uint32_t *csbad=0)

Detailed Description

Definition at line 38 of file XrdOucCRC.hh.

Constructor & Destructor Documentation

XrdOucCRC()

XrdOucCRC::XrdOucCRC ( )

inline

Definition at line 166 of file XrdOucCRC.hh.

{}

~XrdOucCRC()

XrdOucCRC::~XrdOucCRC ( )

inline

Definition at line 167 of file XrdOucCRC.hh.

{}

Member Function Documentation

Calc32C() [1/2]

void XrdOucCRC::Calc32C ( const void *  data, size_t  count, uint32_t *  csval  )

static

Compute a CRC32C page checksums using hardware assist if available.

Parameters

data	Pointer to the data whose checksum it to be computed.
count	The number of bytes pointed to by data.
csval	Pointer to a vector to hold individual page checksums. The vector must be sized: (count/XrdSys::PageSize + (countXrdSys::PageSize != 0)). On return, each element of csval holds the checksum for the associated page.

Definition at line 200 of file XrdOucCRC.cc.

{
   int i, numpages = count/XrdSys::PageSize;
   const uint8_t* dataP = (const uint8_t*)data;
 
// Calculate the CRC32C for each page
//
   for (i = 0; i < numpages; i++)
       {csval[i] = crc32c(0, dataP, XrdSys::PageSize);
        count -= XrdSys::PageSize;
        dataP += XrdSys::PageSize;
       }
 
// if there is anything left, calculate that as well
//
   if (count > 0) csval[i] = crc32c(0, dataP, count);
}

References crc32c(), and XrdSys::PageSize.

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Calc32C() [2/2]

uint32_t XrdOucCRC::Calc32C ( const void *  data, size_t  count, uint32_t  prevcs = 0  )

static

Compute a CRC32C checksum using hardware assist if available.

Parameters

data	Pointer to the data whose checksum it to be computed.
count	The number of bytes pointed to by data.
prevcs	The previous checksum value. The initial checksum of checksum sequence should be zero, the default.

Returns

The CRC32C checksum.

Definition at line 190 of file XrdOucCRC.cc.

{
 
// Return the checksum
//
   return crc32c(prevcs, data, count);
}

References crc32c().

Referenced by XrdOfsCPFile::Append(), XrdOssCsiPages::apply_sequential_aligned_modify(), XrdOssCsiPages::BasicConsistencyCheck(), XrdXrootdPgwBadCS::boInfo(), XrdOssCsiCrcUtils::crc32c_combine(), XrdOssCsiCrcUtils::crc32c_extendwith_zero(), XrdOssCsiCrcUtils::crc32c_split2(), XrdOfsCPFile::Create(), XrdOucPgrwUtils::csCalc(), XrdOssCsiPages::FetchRangeAligned(), XrdOssCsiPages::FetchRangeUnaligned(), XrdOssCsiPages::FetchRangeUnaligned_postblock(), XrdOssCsiPages::FetchRangeUnaligned_preblock(), XrdCl::EcPgReadResponseHandler::HandleResponse(), main(), XrdOssCsiTagstoreFile::Open(), XrdOssCsiPages::pgDoCalc(), XrdOssCsiPages::StoreRangeUnaligned_postblock(), XrdOssCsiPages::StoreRangeUnaligned_preblock(), XrdClHttp::CurlPgReadOp::Success(), XrdOssCsiPages::truncate(), XrdCl::XRootDTransport::UnMarchalStatusMore(), XrdCl::XRootDTransport::UnMarshalStatusBody(), and XrdCksCalccrc32C::Update().

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Combine32C()

uint32_t XrdOucCRC::Combine32C ( uint32_t  Cksum1, uint32_t  Cksum2, int  DLen  )

static

Combine a CRC32C checksum with a checksum computed for an adjacent block.

Parameters

Cksum1	-> The first checksum.
Cksum2	-> The subsequent adjacent checksum.
DLen	-> Length of the data used to compute the Cksum2.

Returns

The combined checksum.

Note

Warning! The Cksum2 must have been computed for the adjacent block of data relative to the computation of Cksum1 otherwise the combined checksum will be invalid.

Definition at line 222 of file XrdOucCRC.cc.

{
   return crc32c_combine(Cksum1, Cksum2, (size_t)DLen);
}

References crc32c_combine().

Referenced by XrdCksCalccrc32C::Combine().

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CRC32()

uint32_t XrdOucCRC::CRC32 ( const unsigned char *  data, int  count  )

static

Compute a CRC32 checksum.

Note

This is a historical method as it uses the very slow CRC32 algoritm.

Parameters

data	Pointer to the data whose checksum it to be computed.
count	The number of bytes pointed to by data.

Returns

The CRC32 checksum.

Definition at line 171 of file XrdOucCRC.cc.

{
   const unsigned int CRC32_XINIT = 0xffffffff;
   const unsigned int CRC32_XOROT = 0xffffffff;
   unsigned int crc = CRC32_XINIT;
 
// Process each byte
//
   while(reclen-- > 0) crc = crctable[(crc ^ *p++) & 0xff] ^ (crc >> 8);
 
// Return XOR out value
//
   return crc ^ CRC32_XOROT;
}

Referenced by XrdOfsHanKey::XrdOfsHanKey(), XrdOucReqID::XrdOucReqID(), XrdCryptoLite_bf32::Decrypt(), XrdCryptoLite_bf32::Encrypt(), XrdOucReqID::Index(), and XrdCmsKey::setHash().

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Ver32C() [1/4]

bool XrdOucCRC::Ver32C ( const void *  data, size_t  count, const uint32_t *  csval, bool *  valok  )

static

Verify a CRC32C page checksums using hardware assist if available.

Parameters

data	Pointer to the data whose checksum it to be verified.
count	The number of bytes pointed to by data.
csval	Pointer to a vector of expected page checksums. The vector must be sized (count/PageSize+(countPageSize != 0)).
valok	Pointer to a vector of the same size as csval to hold the results of the comparison (true matches, o/w false).

Returns

True if all the checksums match with each element of valok set to true. Otherwise, false is returned and false is set in valok for each page that did not match the expected checksum.

Definition at line 283 of file XrdOucCRC.cc.

{
   int i, numpages = count/XrdSys::PageSize;
   const uint8_t* dataP = (const uint8_t*)data;
   uint32_t actualCS;
   bool retval = true;
 
// Calculate the CRC32C for each page and make sure it is the same.
//
   for (i = 0; i < numpages; i++)
       {
        actualCS = crc32c(0, dataP, XrdSys::PageSize);
        if (csval[i] == actualCS) valok[i] = true;
           else valok[i] = retval = false;
        count -= XrdSys::PageSize;
        dataP += XrdSys::PageSize;
       }
 
// if there is anything left, verify that as well
//
   if (count > 0)
      {
       actualCS = crc32c(0, dataP, count);
       if (csval[i] == actualCS) valok[i] = true;
           else valok[i] = retval = false;
      }
 
// All done.
//
   return retval;
}

References crc32c(), and XrdSys::PageSize.

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Ver32C() [2/4]

int XrdOucCRC::Ver32C ( const void *  data, size_t  count, const uint32_t *  csval, uint32_t &  valcs  )

static

Verify a CRC32C page checksums using hardware assist if available.

Parameters

data	Pointer to the data whose checksum it to be verified.
count	The number of bytes pointed to by data.
csval	Pointer to a vector of expected page checksums. The vector must be sized: (count/XrdSys::PageSize + (countXrdSys::PageSize != 0)).
valcs	Where the computed checksum is returned for the page whose verification failed; otherwise it is untouched.

Returns

-1 if all the checksums match. Otherwise, the non-negative index into csval whose checksum does not match.

Definition at line 245 of file XrdOucCRC.cc.

{
   int i, numpages = count/XrdSys::PageSize;
   const uint8_t* dataP = (const uint8_t*)data;
   uint32_t actualCS;
 
// Calculate the CRC32C for each page and make sure it is the same.
//
   for (i = 0; i < numpages; i++)
       {
        actualCS = crc32c(0, dataP, XrdSys::PageSize);
        if (csval[i] != actualCS)
           {valcs = actualCS;
            return i;
           }
        count -= XrdSys::PageSize;
        dataP += XrdSys::PageSize;
       }
 
// if there is anything left, verify that as well
//
   if (count > 0)
      {
       actualCS = crc32c(0, dataP, count);
       if (csval[i] != actualCS)
          {valcs = actualCS;
           return i;
          }
      }
 
// Everything matched.
//
   return -1;
}

References crc32c(), and XrdSys::PageSize.

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Ver32C() [3/4]

bool XrdOucCRC::Ver32C ( const void *  data, size_t  count, const uint32_t *  csval, uint32_t *  valcs  )

static

Verify a CRC32C page checksums using hardware assist if available.

Parameters

data	Pointer to the data whose checksum it to be verified.
count	The number of bytes pointed to by data.
csval	Pointer to a vector of expected page checksums. The vector must be sized (count/PageSize+(countPageSize != 0)).
valcs	Pointer to a vector of the same size as csval to hold the computed checksum.

Returns

True if all the checksums match; false otherwise.

Definition at line 318 of file XrdOucCRC.cc.

{
   int i, numpages = count/XrdSys::PageSize;
   const uint8_t* dataP = (const uint8_t*)data;
   bool retval = true;
 
// Calculate the CRC32C for each page and make sure it is the same.
//
   for (i = 0; i < numpages; i++)
       {
        valcs[i] = crc32c(0, dataP, XrdSys::PageSize);
        if (csval[i] != valcs[i]) retval = false;
        count -= XrdSys::PageSize;
        dataP += XrdSys::PageSize;
       }
 
// if there is anything left, verify that as well
//
   if (count > 0)
      {
       valcs[i] = crc32c(0, dataP, count);
       if (csval[i] != valcs[i]) retval = false;
      }
 
// All done.
//
   return retval;
}

References crc32c(), and XrdSys::PageSize.

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Ver32C() [4/4]

bool XrdOucCRC::Ver32C ( const void *  data, size_t  count, const uint32_t  csval, uint32_t *  csbad = 0  )

static

Verify a CRC32C checksum using hardware assist if available.

Parameters

data	Pointer to the data whose checksum it to be verified.
count	The number of bytes pointed to by data.
csval	The expected checksum.
csbad	If csbad is not nil, the computed checksum is returned.

Returns

True if the expected checksum equals the actual checksum; otherwise, false is returned.

Definition at line 231 of file XrdOucCRC.cc.

{
   uint32_t actualCS;
 
// Verify the checksum
//
   actualCS = crc32c(0, data, count);
   if (valcs) *valcs = actualCS;
   return csval == actualCS;
}

References crc32c().

Referenced by XrdOucPgrwUtils::csVer(), XrdOssCsiPages::pgWritePrelockCheck(), and XrdOfsCPFile::RestoreInfo().

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The documentation for this class was generated from the following files:

• XrdOucCRC.hh
• XrdOucCRC.cc