kopia lustrzana https://github.com/F5OEO/tstools
Python wrapper: Reading TS packets from a TS file will update the PAT
as PAT records are found. Seeking forgets the current PAT. --HG-- extra : convert_revision : svn%3Aeff31bef-be4a-0410-a8fe-e47997df2690/trunk%4098issue20
tibs
rodzic
9a493c00b0
commit
07dc395b13
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@ -498,6 +498,17 @@ call will be remembered).
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PAT({1:0x20})
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>>> f.close()
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Indeed, it will automatically be read in for us as we read its record(s):
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>>> f = TSFile(test_ts_file)
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>>> print f.PAT
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None
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>>> for ii in range(440):
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... p = f.read()
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>>> print f.PAT
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PAT({1:0x20})
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>>> f.close()
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// Local Variables:
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@ -62,6 +62,9 @@ cdef extern from "errno.h":
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cdef extern from "string.h":
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cdef char *strerror(int errnum)
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cdef extern from "stdlib.h":
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cdef void free(void *ptr)
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# Copied from the Pyrex documentation...
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cdef extern from "Python.h":
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# Return a new string object with a copy of the string v as value and
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@ -641,6 +644,8 @@ cdef extern from "ts_fns.h":
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byte **payload, int *payload_len)
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void get_PCR_from_adaptation_field(byte *adapt, int adapt_len, int*got_pcr,
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uint64_t *pcr)
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int build_psi_data(int verbose, byte *payload, int payload_len, PID pid,
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byte **data, int *data_len, int *data_used)
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int find_pat(TS_reader_p tsreader, int max, int verbose, int quiet,
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int *num_read, pidint_list_p *prog_list)
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int find_next_pmt(TS_reader_p tsreader, uint32_t pmt_pid,
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@ -674,7 +679,7 @@ cdef class TSPacket:
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def __cinit__(self,buffer,*args,**kwargs):
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"""The buffer *must* be 188 bytes long, by definition.
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"""
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# An array is easier to access than a string, can can be initialised
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# An array is easier to access than a string, and can be initialised
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# from any sensible sequence. This may not be the most efficient thing
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# to do, though, so later on we might want to consider ways of iterating
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# over TS entries in a file without needing to create TS packets...
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@ -742,11 +747,12 @@ cdef class TSPacket:
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cdef int adapt_len
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cdef char *payload_buf
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cdef int payload_len
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cdef int retval
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PyObject_AsReadBuffer(self.data, &buffer, &length)
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retval = split_TS_packet(<byte *>buffer,&pid,&self._pusi,
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<byte **>&adapt_buf,&adapt_len,
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<byte **>&payload_buf,&payload_len)
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if retval < 0:
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if retval != 0:
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raise TSToolsException,'Error splitting TS packet data'
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if adapt_len == 0:
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self._adapt = None
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@ -815,6 +821,12 @@ cdef class TSFile:
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cdef readonly object PAT # The latest PAT read, if any
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# We have a byte buffer in which we accumulate partial PAT parts,
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# as we read TS packets
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cdef byte *pat_data
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cdef int pat_data_len
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cdef int pat_data_used
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# It appears to be recommended to make __cinit__ expand to take more
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# arguments (if __init__ ever gains them), since both get the same
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# things passed to them. Hmm, normally I'd trust myself, but let's
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@ -837,11 +849,22 @@ cdef class TSFile:
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self.name = filename
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self.mode = mode
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def _clear_pat_data(self):
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"""Clear the buffers we use to accumulate PAT data
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(but not any actual PAT we have acquired).
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"""
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if self.pat_data != NULL:
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free(<void *>self.pat_data)
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self.pat_data = NULL
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self.pat_data_len = self.pat_data_used = 0
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# (__dealloc__ is apparently not allowed to call Python methods,
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# and Python methods don't seem to be allowed to call __dealloc__,
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# so let's have an intermediary)
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cdef _close_for_read(self):
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if self.tsreader != NULL:
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self._clear_pat_data()
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self.PAT = None
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retval = close_TS_reader(&self.tsreader)
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if retval != 0:
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raise TSToolsException,"Error closing file '%s':"\
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@ -880,16 +903,79 @@ cdef class TSFile:
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#return self.mode == 'w' and self.file_stream != NULL
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pass
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cdef _pat_from_prog_list(self, pidint_list_p prog_list):
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try:
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pat = PAT()
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for 0 <= ii < prog_list.length:
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pat[prog_list.number[ii]] = prog_list.pid[ii]
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# And remember it on the file as well
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self.PAT = pat
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finally:
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free_pidint_list(&prog_list)
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cdef _check_pat(self, byte *buffer):
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"""Check if the current buffer represents (another) part of a PAT
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"""
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# Methodology borrowed from tsreport.c::report_ts
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cdef PID pid
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cdef int pusi
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cdef byte *adapt_buf
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cdef int adapt_len
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cdef byte *payload_buf
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cdef int payload_len
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cdef int err
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cdef int retval
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cdef pidint_list_p prog_list
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retval = split_TS_packet(buffer, &pid, &pusi,
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&adapt_buf,&adapt_len,
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&payload_buf,&payload_len)
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if retval != 0:
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# We couldn't split it up - presumably a broken TS packet.
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# Ignore this problem, as the caller might legitimately want
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# to retrieve broken TS packets and inspect them, and our wish
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# to find (parts of) PAT packets shouldn't make that harder
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return
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if pid != 0:
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return # Not a PAT, so we can ignore it
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if pusi and self.pat_data:
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# Lose the PAT data we'd already partially accumulated
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# XXX should we grumble out loud at this? Probably not here,
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# XXX although note that the equivalent C code might
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self._clear_pat_data()
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elif not pusi and not self.pat_data:
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# It's not the start of a PAT, and we haven't got a PAT
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# to continue, so the best we can do is ignore it
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# XXX again, for the moment, quietly
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return
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# Otherwise, call the "accumulate bits of a PAT" function,
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# which does most of the heavy lifting for us
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retval = build_psi_data(False,payload_buf,payload_len,pid,
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&self.pat_data,&self.pat_data_len,
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&self.pat_data_used)
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if retval:
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# For the moment, just give up
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self._clear_pat_data()
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return
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if self.pat_data_len == self.pat_data_used:
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# We've got it all
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try:
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retval = extract_prog_list_from_pat(False,
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self.pat_data,self.pat_data_len,
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&prog_list)
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if not retval:
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self._pat_from_prog_list(prog_list)
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finally:
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self._clear_pat_data()
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cdef TSPacket _next_TSPacket(self):
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"""Read the next TS packet and return an equivalent TSPacket instance.
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``filename`` is given for use in exception messages - it should be the
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name of the file we're reading from (using ``tsreader``). Perhaps the
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tstools C mechanisms should be enhanced to allow that to be recovered
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*from* ``tsreader``.
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name of the file we're reading from (using ``tsreader``).
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"""
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# XXX Should we update self.PAT if the packet has PID 0?
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# XXX See tsreport.c::report_ts for how to do this
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cdef byte *buffer
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if self.tsreader == NULL:
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raise TSToolsException,'No TS stream to read'
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@ -898,16 +984,25 @@ cdef class TSFile:
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raise StopIteration
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elif retval == 1:
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raise TSToolsException,'Error getting next TS packet from file %s'%self.name
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# Remember the buffer we get handed a pointer to is transient
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# so we need to take a copy of it (which we might as well keep in
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# a Python object...)
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buffer_str = PyString_FromStringAndSize(<char *>buffer, TS_PACKET_LEN)
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try:
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return TSPacket(buffer_str)
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new_packet = TSPacket(buffer_str)
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except TSToolsException, what:
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raise TSToolsException,\
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'Error getting next TS packet from file %s (%s)'%(self.name,what)
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# Check whether this packet updates our idea of the current PAT
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# (if we called this before calling TSPacket, then, for instance,
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# TSPacket('\0xff') would cause split_TS_packet, within _check_pat,
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# to output errors on C stderr, followed by TSPacket detecting the
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# problem anyway)
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self._check_pat(buffer)
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return new_packet
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# For Pyrex classes, we define a __next__ instead of a next method
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# in order to form our iterator
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def __next__(self):
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@ -919,7 +1014,12 @@ cdef class TSFile:
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"""Seek to the given offset, which should be a multiple of 188.
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Note that the method does not check the value of 'offset'.
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Seeking causes the file to "forget" any PAT data it may have deduced
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from sequential reading of the file, or by explicit calls of find_PAT.
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"""
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self._clear_pat_data
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self.PAT = None
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retval = seek_using_TS_reader(self.tsreader,offset)
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if retval == 1:
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raise TSToolsException,'Error seeking to %d in file %s'%(offset,self.name)
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@ -952,6 +1052,9 @@ cdef class TSFile:
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The new PAT is also saved as self.PAT (replacing, rather than updating,
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any previous self.PAT object).
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This method is more efficient than using repeated calls of ``read``,
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because it uses the underlying C function to find the next PAT.
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"""
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cdef pidint_list_p prog_list
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cdef int num_read
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return (num_read,None)
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elif retval == 1:
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raise TSToolsException,'Error searching for next PAT'
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try:
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pat = PAT()
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for 0 <= ii < prog_list.length:
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pat[prog_list.number[ii]] = prog_list.pid[ii]
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# And remember it on the file as well
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self.PAT = pat
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finally:
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free_pidint_list(&prog_list)
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return (num_read,pat)
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#try:
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# pat = PAT()
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# for 0 <= ii < prog_list.length:
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# pat[prog_list.number[ii]] = prog_list.pid[ii]
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# # And remember it on the file as well
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# self.PAT = pat
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#finally:
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# free_pidint_list(&prog_list)
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self._pat_from_prog_list(prog_list)
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return (num_read,self.PAT)
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def close(self):
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## Since we don't appear to be able to call our __dealloc__ "method",
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