Wireshark · Ethereal-cvs: [Ethereal-cvs] rev 14666: /trunk/epan/: sigcomp-udvm.c sigcomp-udvm.h sigcomp_state_hdlr.c sigcomp_s

[etxrab@xxxxxxxxxxxx]

User: etxrab
Date: 2005/06/16 04:15 PM

Log:
 From  Paul Ollis:
   epan/sigcomp_state_hdlr.c epan/sigcomp_state_hdlr.h
   ---------------------------------------------------
 
     Function udvm_state_access:
 
         1. Removed the state_vars_valid parameter. It is no longer used.
 
         2. The function now correctly updates each of state_length,
            state_address and state_instruction with saved state value.
 
            [Previously this was only done for state referenced in the SigComp
             message header.]
 
         3. Removed code that (incorrectly) read byte_copy_left from UDVM memory
            within the loop that writes the state to UDVM memory.
 
         4. Removed the code that set the useful values in UDVM memory. This
            should only be done for state referenced in the SigComp message
            header. (The decompress_sigcomp_message function, sets the useful
            values.)
 
 
   epan/sigcomp-udvm.c epan/sigcomp-udvm.h
   ---------------------------------------
 
     Function decompress_sigcomp_message:
 
         1. Added three new parameters; header_len, byte_code_state_len,
            byte_code_id_len.  The byte_code_state_len and byte_code_id_len
            are used to set the useful values in UDVM memory. The
            header_len is required to calculate the cycles available
            for decompression.
 
         2. Various minor corrections to spellings, etc in generated
            messages.
 
         3. Reduced the number of lines of output for print_level_1. Now
            the execution trace shows the instruction name and parameter
            values on one line.
 
            [This was done because, we found that even at the lowest
            level of detail ethereal became unusably slow; running on
            a 500 MHz SPARC. This seems to be related to the number of
            lines produced by the SigComp trace, which can easily be over
            1000 with the modified code.]
 
         4. Removed the used of some floating point functions. In all
            cases they were unnecessary and could potentially cause the
            code to produce the wrong results on some platforms (although
            this is unlikely).
 
         5. The useful values are now set correctly, using the new
            byte_code_state_len and byte_code_id_len parameters.
 
         6. The message header length is now included in the calculation of
            maximum_UDVM_cycles. Previously, the calculation could underestimate
            the value, resulting in the (small) chance that some legitimate
            messages might fail to decompress.
 
            Note: The calculation might now slightly over-estimate the cycles
            but this is a reasonable thing to do.
 
         7. Implemented the PUSH, POP, CALL and RETURN instructions.
 
            Note: The two SORT instructions and the CRC and SHA-1 instructions
            are still not implemented.
 
         8. The COPY and COPY-LITERAL instructions now apply the
            byte-copying-rules to the source address as well as the destination
            address.
 
         9. The COPY-LITERAL and COPY-OFFSET now correctly handle the
            destination operand. Previously, it was possible for the destination
            to be left at byte_copy_right when it should be left at
            byte_copy_left.
 
         10. All three COPY instructions will now behave correctly if the source
             or destination start at byte_copy_right; i.e. they read/write to
             byte_copy_right, byte_copy_right+1, etc. Previously the parameters
             would wrap to byte_copy_left.
 
         11. The COPY-OFFSET instruction now correctly calculates the source
             address for all values of offset. Previously a very large offset
             (greater than the circular buffer size) could cause the starting
             position to be mis-calculated.
 
         12. Modulo 65536 arithmetic has been added in some places where it was
             missing.
 
             [Only when noticed, we have not been able to check all the code.]
 
         13. Some redundant code was removed for the INPUT-BITS instruction.
             Also, INPUT-BITS (0, x, x) now correctly discards spare bits when
             the P-bit, has changed.
 
         14. Corrected the cycles used calculation for the INPUT-BITS
             instruction.
 
         15. Corrected some minor cases where the used_udvm_cycles was not
             incremented.
 
             [Not really a problem, but it allowed us to verify correctness with
             some of the SigComp torture tests.]
 
         16. Removed some redundant code in INPUT-HUFFMAN (and reorganised some
             comments to keep them making sense).
 
 
     Function decomp_dispatch_get_bits:
 
         1. This has been rewritten. The original version could not correctly
            handle requests for more than 8 bits. The new version is cleaner and
            correctly handles all cases.

Directory: /trunk/epan/
  Changes    Path                    Action
  +649 -506  sigcomp-udvm.c          Modified
  +3 -1      sigcomp-udvm.h          Modified
  +626 -668  sigcomp_state_hdlr.c    Modified
  +45 -45    sigcomp_state_hdlr.h    Modified



http://anonsvn.ethereal.com/viewcvs/viewcvs.py?rev=14666&view=rev