Function report

Linux Kernel

v5.5.9

Brick Technologies Co., Ltd

Source Code:lib\zlib_inflate\inflate.c Create Date:2022-07-28 06:57:59
Last Modify:2020-03-12 14:18:49 Copyright©Brick
home page Tree
Annotation kernel can get tool activityDownload SCCTChinese

Name:late() uses a state machine to process as much input data and generate asmuch output data as possible before returning

Proto:int zlib_inflate(z_streamp strm, int flush)

Type:int

Parameter:

TypeParameterName
z_streampstrm>next_out, given the space available and the provided input--the effect
intflush
332  static const unsigned short order[19] = {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15}
338  If >next_out, given the space available and the provided input--the effect == NULL || not visible by applications == NULL || next input byte == NULL && number of bytes available at next_in != 0 Then Return Z_STREAM_ERROR
342  state = not visible by applications
344  If current inflate mode == waiting for type bits, including last-flag bit Then current inflate mode = same, but skip check to exit inflate on new block
345  Load registers with state in inflate() for speed ()
346  in = have
347  out = left
348  ret = Allowed flush values; see deflate() and inflate() below for details
349  cycle switch current inflate mode
351  Case current inflate mode == waiting for magic header
352  If 0 true for zlib, bit 1 true for gzip == 0 Then
353  current inflate mode = same, but skip check to exit inflate on new block
354  Break
356  Assure that there are at least n bits in the bit accumulator. If there isnot enough available input to do that, then return from inflate(). (16)
357  If ((Return the low n bits of the bit accumulator (n < 16) (8) << 8) + (hold >> 8)) % 31 Then
359  last error message, NULL if no error = "incorrect header check"
360  current inflate mode = got a data error -- remain here until reset
361  Break
363  If Return the low n bits of the bit accumulator (n < 16) (4) != Possible values of the data_type field Then
364  last error message, NULL if no error = "unknown compression method"
365  current inflate mode = got a data error -- remain here until reset
366  Break
368  Remove n bits from the bit accumulator (4)
369  len = Return the low n bits of the bit accumulator (n < 16) (4) + 8
370  If len > log base 2 of requested window size Then
371  last error message, NULL if no error = "invalid window size"
372  current inflate mode = got a data error -- remain here until reset
373  Break
375  zlib header max distance (INFLATE_STRICT) = 1U << len
376  adler32 value of the uncompressed data = protected copy of check value = Update a running Adler-32 checksum with the bytes buf[0..len-1] andreturn the updated checksum. If buf is NULL, this function returnsthe required initial value for the checksum.An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
377  current inflate mode = If hold & 0x200 Then waiting for dictionary check value Else waiting for type bits, including last-flag bit
378  Clear the input bit accumulator ()
379  Break
380  Case current inflate mode == waiting for dictionary check value
381  Assure that there are at least n bits in the bit accumulator. If there isnot enough available input to do that, then return from inflate(). (32)
382  adler32 value of the uncompressed data = protected copy of check value = Reverse the bytes in a 32-bit value (hold)
383  Clear the input bit accumulator ()
384  current inflate mode = waiting for inflateSetDictionary() call
386  Case current inflate mode == waiting for inflateSetDictionary() call
387  If rue if dictionary provided == 0 Then
388  Restore state from registers in inflate() ()
389  Return Z_NEED_DICT
391  adler32 value of the uncompressed data = protected copy of check value = Update a running Adler-32 checksum with the bytes buf[0..len-1] andreturn the updated checksum. If buf is NULL, this function returnsthe required initial value for the checksum.An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
392  current inflate mode = waiting for type bits, including last-flag bit
394  Case current inflate mode == waiting for type bits, including last-flag bit
395  If flush == Only for inflate at present Then Go to inf_leave
397  Case current inflate mode == same, but skip check to exit inflate on new block
398  If rue if processing last block Then
399  Remove zero to seven bits as needed to go to a byte boundary ()
400  current inflate mode = waiting for 32-bit check value
401  Break
403  Assure that there are at least n bits in the bit accumulator. If there isnot enough available input to do that, then return from inflate(). (3)
404  rue if processing last block = Return the low n bits of the bit accumulator (n < 16) (1)
405  Remove n bits from the bit accumulator (1)
407  Case Return the low n bits of the bit accumulator (n < 16) (2) == 0
408  current inflate mode = waiting for stored size (length and complement)
409  Break
410  Case Return the low n bits of the bit accumulator (n < 16) (2) == 1
411  Return state with length and distance decoding tables and index sizes set tofixed code decoding. This returns fixed tables from inffixed.h.
412  current inflate mode = waiting for length/lit code
413  Break
414  Case Return the low n bits of the bit accumulator (n < 16) (2) == 2
415  current inflate mode = waiting for dynamic block table lengths
416  Break
417  Case Return the low n bits of the bit accumulator (n < 16) (2) == 3
418  last error message, NULL if no error = "invalid block type"
419  current inflate mode = got a data error -- remain here until reset
421  Remove n bits from the bit accumulator (2)
422  Break
423  Case current inflate mode == waiting for stored size (length and complement)
424  Remove zero to seven bits as needed to go to a byte boundary ()
425  Assure that there are at least n bits in the bit accumulator. If there isnot enough available input to do that, then return from inflate(). (32)
426  If (hold & 0xffff) != ( hold >> 16 ^ 0xffff) Then
427  last error message, NULL if no error = "invalid stored block lengths"
428  current inflate mode = got a data error -- remain here until reset
429  Break
431  literal or length of data to copy = hold & 0xffff
432  Clear the input bit accumulator ()
433  current inflate mode = /o: waiting for input or output to copy stored block
435  Case current inflate mode == /o: waiting for input or output to copy stored block
436  copy = literal or length of data to copy
437  If copy Then
438  If copy > have Then copy = have
439  If copy > left Then copy = left
440  If copy == 0 Then Go to inf_leave
441  No 3D Now!(put, next, copy)
442  have -= copy
443  next += copy
444  left -= copy
445  put += copy
446  literal or length of data to copy -= copy
447  Break
449  current inflate mode = waiting for type bits, including last-flag bit
450  Break
451  Case current inflate mode == waiting for dynamic block table lengths
452  Assure that there are at least n bits in the bit accumulator. If there isnot enough available input to do that, then return from inflate(). (14)
453  umber of length code lengths = Return the low n bits of the bit accumulator (n < 16) (5) + 257
454  Remove n bits from the bit accumulator (5)
455  umber of distance code lengths = Return the low n bits of the bit accumulator (n < 16) (5) + 1
456  Remove n bits from the bit accumulator (5)
457  umber of code length code lengths = Return the low n bits of the bit accumulator (n < 16) (4) + 4
458  Remove n bits from the bit accumulator (4)
460  If umber of length code lengths > 286 || umber of distance code lengths > 30 Then
461  last error message, NULL if no error = "too many length or distance symbols"
462  current inflate mode = got a data error -- remain here until reset
463  Break
466  umber of code lengths in lens[] = 0
467  current inflate mode = waiting for code length code lengths
469  Case current inflate mode == waiting for code length code lengths
470  When umber of code lengths in lens[] < umber of code length code lengths cycle
471  Assure that there are at least n bits in the bit accumulator. If there isnot enough available input to do that, then return from inflate(). (3)
472  mporary storage for code lengths [order[umber of code lengths in lens[] ++]] = Return the low n bits of the bit accumulator (n < 16) (3)
473  Remove n bits from the bit accumulator (3)
475  When umber of code lengths in lens[] < 19 cycle
476  mporary storage for code lengths [order[umber of code lengths in lens[] ++]] = 0
477  xt available space in codes[] = space for code tables
478  starting table for length/literal codes = xt available space in codes[]
479  dex bits for lencode = 7
480  ret = zlib_inflate_table(CODES, mporary storage for code lengths , 19, & (xt available space in codes[] ), & (dex bits for lencode ), work area for code table building )
482  If ret Then
483  last error message, NULL if no error = "invalid code lengths set"
484  current inflate mode = got a data error -- remain here until reset
485  Break
487  umber of code lengths in lens[] = 0
488  current inflate mode = waiting for length/lit and distance code lengths
490  Case current inflate mode == waiting for length/lit and distance code lengths
491  When umber of code lengths in lens[] < umber of length code lengths + umber of distance code lengths cycle
492  cycle
497  If ffset in table or code value < 16 Then
502  Else
503  If ffset in table or code value == 16 Then
515  Else if ffset in table or code value == 17 Then
522  Else
529  If umber of code lengths in lens[] + copy > umber of length code lengths + umber of distance code lengths Then
534  When copy-- cycle
535  mporary storage for code lengths [umber of code lengths in lens[] ++] = len
540  If current inflate mode == got a data error -- remain here until reset Then Break
543  xt available space in codes[] = space for code tables
544  starting table for length/literal codes = xt available space in codes[]
545  dex bits for lencode = 9
546  ret = zlib_inflate_table(LENS, mporary storage for code lengths , umber of length code lengths , & (xt available space in codes[] ), & (dex bits for lencode ), work area for code table building )
548  If ret Then
549  last error message, NULL if no error = "invalid literal/lengths set"
550  current inflate mode = got a data error -- remain here until reset
551  Break
553  starting table for distance codes = xt available space in codes[]
554  dex bits for distcode = 6
555  ret = zlib_inflate_table(DISTS, mporary storage for code lengths + umber of length code lengths , umber of distance code lengths , & (xt available space in codes[] ), & (dex bits for distcode ), work area for code table building )
557  If ret Then
558  last error message, NULL if no error = "invalid distances set"
559  current inflate mode = got a data error -- remain here until reset
560  Break
562  current inflate mode = waiting for length/lit code
564  Case current inflate mode == waiting for length/lit code
565  If have >= 6 && left >= 258 Then
566  Restore state from registers in inflate() ()
567  Decode literal, length, and distance codes and write out the resultingliteral and match bytes until either not enough input or output isavailable, an end-of-block is encountered, or a data error is encountered
568  Load registers with state in inflate() for speed ()
569  Break
571  cycle
572  this = starting table for length/literal codes [Return the low n bits of the bit accumulator (n < 16) (dex bits for lencode )]
573  If s in this part of the code <= bits Then Break
574  Get a byte of input into the bit accumulator, or return from inflate()if there is no input available. ()
576  If peration, extra bits, table bits && (peration, extra bits, table bits & 0xf0) == 0 Then
577  last = this
578  cycle
584  Remove n bits from the bit accumulator (s in this part of the code )
586  Remove n bits from the bit accumulator (s in this part of the code )
587  literal or length of data to copy = ffset in table or code value
588  If peration, extra bits, table bits == 0 Then
589  current inflate mode = waiting for output space to write literal
590  Break
592  If peration, extra bits, table bits & 32 Then
593  current inflate mode = waiting for type bits, including last-flag bit
594  Break
596  If peration, extra bits, table bits & 64 Then
597  last error message, NULL if no error = "invalid literal/length code"
598  current inflate mode = got a data error -- remain here until reset
599  Break
601  xtra bits needed = peration, extra bits, table bits & 15
602  current inflate mode = waiting for length extra bits
604  Case current inflate mode == waiting for length extra bits
605  If xtra bits needed Then
606  Assure that there are at least n bits in the bit accumulator. If there isnot enough available input to do that, then return from inflate(). (xtra bits needed )
607  literal or length of data to copy += Return the low n bits of the bit accumulator (n < 16) (xtra bits needed )
608  Remove n bits from the bit accumulator (xtra bits needed )
610  current inflate mode = waiting for distance code
612  Case current inflate mode == waiting for distance code
613  cycle
614  this = starting table for distance codes [Return the low n bits of the bit accumulator (n < 16) (dex bits for distcode )]
615  If s in this part of the code <= bits Then Break
616  Get a byte of input into the bit accumulator, or return from inflate()if there is no input available. ()
618  If (peration, extra bits, table bits & 0xf0) == 0 Then
619  last = this
620  cycle
626  Remove n bits from the bit accumulator (s in this part of the code )
628  Remove n bits from the bit accumulator (s in this part of the code )
629  If peration, extra bits, table bits & 64 Then
630  last error message, NULL if no error = "invalid distance code"
631  current inflate mode = got a data error -- remain here until reset
632  Break
634  distance back to copy string from = ffset in table or code value
635  xtra bits needed = peration, extra bits, table bits & 15
636  current inflate mode = waiting for distance extra bits
638  Case current inflate mode == waiting for distance extra bits
639  If xtra bits needed Then
640  Assure that there are at least n bits in the bit accumulator. If there isnot enough available input to do that, then return from inflate(). (xtra bits needed )
641  distance back to copy string from += Return the low n bits of the bit accumulator (n < 16) (xtra bits needed )
642  Remove n bits from the bit accumulator (xtra bits needed )
651  If distance back to copy string from > valid bytes in the window + out - left Then
652  last error message, NULL if no error = "invalid distance too far back"
653  current inflate mode = got a data error -- remain here until reset
654  Break
656  current inflate mode = waiting for output space to copy string
658  Case current inflate mode == waiting for output space to copy string
659  If left == 0 Then Go to inf_leave
660  copy = out - left
661  If distance back to copy string from > copy Then
662  copy = distance back to copy string from - copy
663  If copy > window write index Then
667  Else from = allocated sliding window, if needed + window write index - copy
669  If copy > literal or length of data to copy Then copy = literal or length of data to copy
671  Else
672  from = put - distance back to copy string from
673  copy = literal or length of data to copy
675  If copy > left Then copy = left
676  left -= copy
677  literal or length of data to copy -= copy
678  Do
679  put++ = from++
680  When --copy cycle
681  If literal or length of data to copy == 0 Then current inflate mode = waiting for length/lit code
682  Break
683  Case current inflate mode == waiting for output space to write literal
684  If left == 0 Then Go to inf_leave
685  put++ = literal or length of data to copy
686  left--
687  current inflate mode = waiting for length/lit code
688  Break
689  Case current inflate mode == waiting for 32-bit check value
690  If 0 true for zlib, bit 1 true for gzip Then
691  Assure that there are at least n bits in the bit accumulator. If there isnot enough available input to do that, then return from inflate(). (32)
692  out -= left
693  total nb of bytes output so far += out
694  protected copy of output count += out
695  If out Then adler32 value of the uncompressed data = protected copy of check value = check function to use adler32() for zlib or crc32() for gzip (protected copy of check value , put - out, out)
698  out = left
699  If Reverse the bytes in a 32-bit value (hold) != protected copy of check value Then
705  Clear the input bit accumulator ()
707  current inflate mode = ished check, done -- remain here until reset
709  Case current inflate mode == ished check, done -- remain here until reset
710  ret = Z_STREAM_END
711  Go to inf_leave
712  Case current inflate mode == got a data error -- remain here until reset
713  ret = Z_DATA_ERROR
714  Go to inf_leave
715  Case current inflate mode == got an inflate() memory error -- remain here until reset
716  Return Z_MEM_ERROR
717  Case current inflate mode == SYNC
718  Default
719  Return Z_STREAM_ERROR
727  inf_leave :
728  Restore state from registers in inflate() ()
729  If window size or zero if not using window || current inflate mode < waiting for 32-bit check value && out != remaining free space at next_out Then Update the window with the last wsize (normally 32K) bytes written beforereturning. This is only called when a window is already in use, or whenoutput has been written during this inflate call, but the end of the deflatestream has not been reached yet
732  in -= number of bytes available at next_in
733  out -= remaining free space at next_out
734  total nb of input bytes read so far += in
735  total nb of bytes output so far += out
736  protected copy of output count += out
737  If 0 true for zlib, bit 1 true for gzip && out Then adler32 value of the uncompressed data = protected copy of check value = check function to use adler32() for zlib or crc32() for gzip (protected copy of check value , next output byte should be put there - out, out)
741  best guess about the data type: ascii or binary = umber of bits in "in" + If rue if processing last block Then 64 Else 0 + If current inflate mode == waiting for type bits, including last-flag bit Then 128 Else 0
744  If flush == Z_PACKET_FLUSH && ret == Allowed flush values; see deflate() and inflate() below for details && remaining free space at next_out != 0 && number of bytes available at next_in == 0 Then Return Returns true if inflate is currently at the end of a block generated byZ_SYNC_FLUSH or Z_FULL_FLUSH
748  If ( in == 0 && out == 0 || flush == Z_FINISH ) && ret == Allowed flush values; see deflate() and inflate() below for details Then ret = Z_BUF_ERROR
751  Return ret
Caller
NameDescribe
zlib_inflate_blobUtility function: initialize zlib, unpack binary blob, clean up zlib,* return len or negative error code.
__gunzipIncluded from initramfs et al code