Hi All,

Is it possible to output the content of a particular file from a zip file?
For example, in the attached ziptest.c I want to get the contents of a 
particular file Class3.class from testclasses.zip into a buffer, can 
anyone point out what I need to change in the code?

Thx in advance
Prasanta Sadhukhan wrote:
>> Thanks Glynn.
>> I tried to rectify the flaw and now I am getting the whole file 
>> contents from the zip file, ie., it is outputting the contents of the 
>> file stored in the zipfile.
>> But Actually, I wanted only to list the content of the zip file as 
>> zipinfo does.
>>
>> Regards
>> Prasanta
>> Glynn Clements wrote:
>>> Prasanta Sadhukhan wrote:
>>>
>>>  
>>>> I have tried to create a ziptest code with the information found 
>>>> but when I tried to inflate the contents by calling inflate() 
>>>> [line68], I am getting Z_DATA_ERROR citing  input data is corrupted 
>>>> or not conforming to zlib format but I can do zipinfo or unzip on 
>>>> the attached ziptest.zip file successfully (and also the zip header 
>>>> is found to be valid by the header validity check done in the program)
>>>> Can anyone point me as to what should I being more to get rid of 
>>>> this problem?
>>>>     
>>>
>>> I've found 3 flaws:
>>>
>>> 1. You're not skipping over the variable-length fields (file name and
>>> extra field) at the end of the header; add:
>>>
>>>     fseek(file, SH(&h[LOCFIL]), SEEK_CUR);
>>>     fseek(file, SH(&h[LOCEXT]), SEEK_CUR);
>>>
>>> after reading the header but before calling inf().
>>>
>>> 2. You're trying to inflate() everything up to end-of-file, when you
>>> should be using the compressed length from the header (LOCSIZ) to
>>> determine how much compressed data is available (even with only one
>>> file, the central directory occurs at the end of the file).
>>>
>>> 3. This one wasn't obvious until I looked at the unzip source code. 
>>> You need to call inflateInit2(&strm, -15) rather than inflateInit(),
>>> in order to have it process "raw" data. zlib.h says:
>>>
>>>      windowBits can also be -8..-15 for raw inflate. In this case, 
>>> -windowBits
>>>    determines the window size. inflate() will then process raw 
>>> deflate data,
>>>    not looking for a zlib or gzip header, not generating a check 
>>> value, and not
>>>    looking for any check values for comparison at the end of the 
>>> stream. This
>>>    is for use with other formats that use the deflate compressed 
>>> data format
>>>    such as zip. ...
>>>
>>> IOW, inflateInit() expects the data to be "wrapped" with a zlib or
>>> gzip header and trailer, but ZIP files don't have these.
>>>
>>> After fixing the above issues, I get C source code on stdout.
>>>
>>>   
>>