Segmentation fault in HuffmanDecoder::Get

[chluo1997]

Hi, there.

There is a segmentation fault in the newest master branch.

Here is the reproducing command:
jpeg poc /dev/null

Program received signal SIGSEGV, Segmentation fault.
HuffmanDecoder::Get (this=0x0, io=0x7933c8)
    at /home/users/chluo/libjpeg/codestream/../coding/huffmandecoder.hpp:112
warning: Source file is more recent than executable.
(gdb) bt
#0  HuffmanDecoder::Get (this=0x0, io=0x7933c8)
    at /home/users/chluo/libjpeg/codestream/../coding/huffmandecoder.hpp:112
#1  0x0000000000491388 in LosslessScan::ParseMCU (this=0x793250, prev=0x7fffffffda90,
    top=0x7fffffffda70) at losslessscan.cpp:374
#2  0x0000000000491b4a in LosslessScan::ParseMCU (this=0x793250)
    at losslessscan.cpp:440
#3  0x000000000043aca1 in JPEG::ReadInternal (this=0x7904c8, tags=0x7fffffffdd40)
    at jpeg.cpp:345
#4  0x000000000043988b in JPEG::Read (this=0x7904c8, tags=0x7fffffffdd40)
    at jpeg.cpp:210
#5  0x000000000041cabb in Reconstruct (infile=<optimized out>,
    outfile=0x7fffffffe6fc "/dev/null", colortrafo=1, alpha=0x0, upsample=true)
    at reconstruct.cpp:121
#6  0x0000000000408b6a in main (argc=<optimized out>, argv=0x0) at main.cpp:747

poc.zip

[thorfdbg]

Thank you, this should be fixed in the latest trunk.