Cannot use `deflateInit` to compress the modified data

Question

I'm developing an LSP that monitors HTTP traffic and modifies the source HTML code of every webpage. To modify HTTP response that are chunked, I used zlib and inflate and successfully decompressed the data using the following main line of code:

r = inflateInit2(&z, 16 + MAX_WBITS);
...
r = inflate(&z, 0);

Now, after modification, I want to re-compress the data using the exact same method, so I'm using the following line of code but it returns -2.

r = deflateInit(&o, 16 + MAX_WBITS);

If I change 16+MAX_WBITS it returns SUCCESS but it's not the same method and returns an invalid response after deflate.

How can I achieve my goal?

score 1 · Answer 1 · edited Apr 09 '16 at 12:59

1

You need to use deflateInit2(). The fourth argument would be the 16 + MAX_WBITS. Please read the documentation in zlib.h

edited Apr 09 '16 at 12:59

rene

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answered Feb 06 '15 at 22:52

Mark Adler

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You are right, now it's fixed but after `deflate`, `total_in=0x00000669` while `total_out=0x0000000a`! Why is that?! – Javid Feb 06 '15 at 23:49
You need to post a new question with the details. – Mark Adler Feb 07 '15 at 06:32

Cannot use `deflateInit` to compress the modified data

1 Answers1