Classes
class	Key

Public Member Functions
	__init__ (self, filename)

	__del__ (self)

	normalize (self, end=None, seekfree=None, nbytesfree=None, nbytesname=None, seekinfo=None)

	__iter__ (self)

	__next__ (self)

Public Attributes
	rootfile = open(filename, 'rb')
	binary root file

	version = int.from_bytes(self.rootfile.read(4), byteorder)
	root/file format version

tuple	large = (self.version >= 1000000)
	are file location pointers 4 or 8 bits?

int	wordlen = 8 if self.large else 4
	size of file location pointers

	begin = int.from_bytes(self.rootfile.read(4), byteorder)
	pointer to first data record

	end = int.from_bytes(self.rootfile.read(self.wordlen), byteorder)
	pointer to first free word at the EOF

	seekfree = int.from_bytes(self.rootfile.read(self.wordlen), byteorder)
	pointer to FREE data record

	nbytesfree = int.from_bytes(self.rootfile.read(4), byteorder)
	number of bytes in FREE data record

	nfree = int.from_bytes(self.rootfile.read(4), byteorder)
	number of free data records

	nbytesname = int.from_bytes(self.rootfile.read(4), byteorder)
	number of bytes in TNamed at creation time

	units = int.from_bytes(self.rootfile.read(1), byteorder)
	number of bytes for file pointers

	compress = int.from_bytes(self.rootfile.read(4), byteorder)
	compression level and algorithm

	seekinfo = int.from_bytes(self.rootfile.read(self.wordlen), byteorder)
	pointer to TStreamerInfo record

	nbytesinfo = int.from_bytes(self.rootfile.read(self.wordlen), byteorder)
	number of bytes in TStreamerInfo record

str	uuid = self.rootfile.read(18)
	universal unique ID

str	header = self.rootfile.read(self.begin)
	binary header

int	seekkeys = 0
	pointer to KeysList record

Detailed Description

Interface to binary root file content

Definition at line 21 of file b2root.py.

Constructor & Destructor Documentation

◆ init()

__init__	(		self,
			filename )

Open a root file and read its header

Definition at line 26 of file b2root.py.

    def __init__(self, filename):
        """
        Open a root file and read its header
        """
 
        self.rootfile = open(filename, 'rb')
        root = self.rootfile.read(4)
        if root != b'root':
            raise Exception(f"{filename} is not a root file")
        
        self.version = int.from_bytes(self.rootfile.read(4), byteorder)
        
        self.large = (self.version >= 1000000)
        
        self.wordlen = 8 if self.large else 4
        
        self.begin = int.from_bytes(self.rootfile.read(4), byteorder)
        
        self.end = int.from_bytes(self.rootfile.read(self.wordlen), byteorder)
        
        self.seekfree = int.from_bytes(self.rootfile.read(self.wordlen), byteorder)
        
        self.nbytesfree = int.from_bytes(self.rootfile.read(4), byteorder)
        
        self.nfree = int.from_bytes(self.rootfile.read(4), byteorder)
        
        self.nbytesname = int.from_bytes(self.rootfile.read(4), byteorder)
        
        self.units = int.from_bytes(self.rootfile.read(1), byteorder)
        
        self.compress = int.from_bytes(self.rootfile.read(4), byteorder)
        
        self.seekinfo = int.from_bytes(self.rootfile.read(self.wordlen), byteorder)
        
        self.nbytesinfo = int.from_bytes(self.rootfile.read(self.wordlen), byteorder)
        
        self.uuid = self.rootfile.read(18)
        self.rootfile.seek(0)
        
        self.header = self.rootfile.read(self.begin)
        self.rootfile.seek(self.begin)
        
        self.seekkeys = 0

◆ del()

__del__ ( self )

Close file

Definition at line 71 of file b2root.py.

    def __del__(self):
        """
        Close file
        """
 
        if hasattr(self, 'rootfile'):
            self.rootfile.close()
 

Member Function Documentation

◆ iter()

__iter__ ( self )

iterator interface

Definition at line 112 of file b2root.py.

    def __iter__(self):
        """
        iterator interface
        """
 
        return self
 

◆ next()

__next__ ( self )

Iterate to next key

Definition at line 210 of file b2root.py.

    def __next__(self):
        """
        Iterate to next key
        """
 
        pos = self.rootfile.tell()
        large = pos > 0x80000000
        nbytes = int.from_bytes(self.rootfile.read(4), byteorder)
        if (nbytes == 0):
            raise StopIteration()
        self.rootfile.seek(-4, 1)
        result = self.Key(self.rootfile.read(nbytes), large)
        if pos == self.seekfree:
            result.showname = b'FreeSegments'
        elif pos == self.seekinfo:
            result.showname = b'StreamerInfo'
        elif pos == self.seekkeys:
            result.showname = b'KeysList'
 
        if result.showname == b'TFile':
            result.filename, pos = result.get_string(result.data, 0)
            result.filetitle, pos = result.get_string(result.data, pos)
            result.version = int.from_bytes(result.data[pos:pos+2], byteorder)
            result.nbyteskeys = int.from_bytes(result.data[pos+10:pos+14], byteorder)
            result.nbytesname = int.from_bytes(result.data[pos+14:pos+18], byteorder)
            if result.version > 1000:
                result.seekdir = int.from_bytes(result.data[pos+18:pos+26], byteorder)
                result.seekparent = int.from_bytes(result.data[pos+26:pos+34], byteorder)
                self.seekkeys = int.from_bytes(result.data[pos+34:pos+42], byteorder)
            else:
                result.seekdir = int.from_bytes(result.data[pos+18:pos+22], byteorder)
                result.seekparent = int.from_bytes(result.data[pos+22:pos+26], byteorder)
                self.seekkeys = int.from_bytes(result.data[pos+26:pos+30], byteorder)
        return result
 
 

◆ normalize()

normalize	(	self,
		end = None,
		seekfree = None,
		nbytesfree = None,
		nbytesname = None,
		seekinfo = None )

Set UUID to zero and adjust pointers that are given as arguments

Definition at line 79 of file b2root.py.

    def normalize(self, end=None, seekfree=None, nbytesfree=None, nbytesname=None, seekinfo=None):
        """
        Set UUID to zero and adjust pointers that are given as arguments
        """
 
        if end:
            self.end = end
        if seekfree:
            self.seekfree = seekfree
        if nbytesfree:
            self.nbytesfree = nbytesfree
        if nbytesname:
            self.nbytesname = nbytesname
        if seekinfo:
            self.seekinfo = seekinfo
        self.uuid = b'\x00' * 18
 
        self.header = b'root' \
            + self.version.to_bytes(4, byteorder) \
            + self.begin.to_bytes(4, byteorder) \
            + self.end.to_bytes(self.wordlen, byteorder) \
            + self.seekfree.to_bytes(self.wordlen, byteorder) \
            + self.nbytesfree.to_bytes(4, byteorder) \
            + self.nfree.to_bytes(4, byteorder) \
            + self.nbytesname.to_bytes(4, byteorder) \
            + self.units.to_bytes(1, byteorder) \
            + self.compress.to_bytes(4, byteorder) \
            + self.seekinfo.to_bytes(self.wordlen, byteorder) \
            + self.nbytesinfo.to_bytes(self.wordlen, byteorder) \
            + self.uuid
        nzero = self.begin - len(self.header)
        self.header += b'\x00' * nzero
 

Member Data Documentation

◆ begin

begin = int.from_bytes(self.rootfile.read(4), byteorder)

pointer to first data record

Definition at line 43 of file b2root.py.

◆ compress

compress = int.from_bytes(self.rootfile.read(4), byteorder)

compression level and algorithm

Definition at line 57 of file b2root.py.

◆ end

end = int.from_bytes(self.rootfile.read(self.wordlen), byteorder)

pointer to first free word at the EOF

Definition at line 45 of file b2root.py.

◆ header

str header = self.rootfile.read(self.begin)

binary header

Definition at line 66 of file b2root.py.

◆ large

tuple large = (self.version >= 1000000)

are file location pointers 4 or 8 bits?

Definition at line 39 of file b2root.py.

◆ nbytesfree

nbytesfree = int.from_bytes(self.rootfile.read(4), byteorder)

number of bytes in FREE data record

Definition at line 49 of file b2root.py.

◆ nbytesinfo

nbytesinfo = int.from_bytes(self.rootfile.read(self.wordlen), byteorder)

number of bytes in TStreamerInfo record

Definition at line 61 of file b2root.py.

◆ nbytesname

nbytesname = int.from_bytes(self.rootfile.read(4), byteorder)

number of bytes in TNamed at creation time

Definition at line 53 of file b2root.py.

◆ nfree

nfree = int.from_bytes(self.rootfile.read(4), byteorder)

number of free data records

Definition at line 51 of file b2root.py.

◆ rootfile

rootfile = open(filename, 'rb')

binary root file

Definition at line 32 of file b2root.py.

◆ seekfree

seekfree = int.from_bytes(self.rootfile.read(self.wordlen), byteorder)

pointer to FREE data record

Definition at line 47 of file b2root.py.

◆ seekinfo

seekinfo = int.from_bytes(self.rootfile.read(self.wordlen), byteorder)

pointer to TStreamerInfo record

Definition at line 59 of file b2root.py.

◆ seekkeys

int seekkeys = 0

pointer to KeysList record

Definition at line 69 of file b2root.py.

◆ units

units = int.from_bytes(self.rootfile.read(1), byteorder)

number of bytes for file pointers

Definition at line 55 of file b2root.py.

◆ uuid

str uuid = self.rootfile.read(18)

universal unique ID

Definition at line 63 of file b2root.py.

◆ version

version = int.from_bytes(self.rootfile.read(4), byteorder)

root/file format version

Definition at line 37 of file b2root.py.

◆ wordlen

int wordlen = 8 if self.large else 4

size of file location pointers

Definition at line 41 of file b2root.py.

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

framework/scripts/B2Tools/b2root.py

Classes

Public Member Functions

Public Attributes