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using zlib

Started by Endar Nov 24, 2004 at 2:07 AM 5 replies 1.7k views

Original Post

139

Nov 24, 2004 at 2:07 AM

Hi. Does anyone know how to use zlib to view and extract a particular file from an archive? I have taken a look at the info on the site, and it says how to decompress some data in memory, but I can't see how to look view what files are in an archive.

Endurion

1,263

Endurion

Nov 24, 2004 at 2:56 AM

The whole zlib isn't particularely clear, but look into the contrib folder.

If you're after PKZip (Winzip etc.) look into minizip.c/.h, it will behave like a command line zip tool and shows how to read and write a file from an archive.

There's also a file for GZip.

[edit: cleared up]

[Edited by - Endurion on November 24, 2004 3:56:49 AM]

Endar

Author

139

Endar

Nov 24, 2004 at 7:09 AM

Okay, I've looked, but it seems that the function "file_uncompress" deletes the archive after uncompressing, so I thought to use "gz_uncompress", but what is the definition 'gzFile'.

Is it a typedef of something or an defined type such as a struct?

I've been looking, but as of yet, I haven't been able to find the definition of it.

Qw3r7yU10p!

Nov 24, 2004 at 7:26 AM

from the manual:

Quote:

int gzread (gzFile file, voidp buf, unsigned len);
Reads the given number of uncompressed bytes from the compressed file.

typedef voidp gzFile;

(voidp is void*)

AxoDosS

Nov 24, 2004 at 7:30 AM

I hope that this will be helpful. I dont know if it works.
BTW the functions that I use here are defined in "unzip.h"

unzFile openZipFile(const char* strZipPackage, const char* strFile){	unzFile fp = unzOpen(strZipPackage);	if (fp == NULL) return NULL;	if (unzLocateFile(fp,strFile,0) != UNZ_OK)	{		unzClose(fp);		return NULL;	}	if (unzOpenCurrentFile(fp) != UNZ_OK)	{		unzClose(fp);		return NULL;	}	return fp;}void closeZipFile(unzFile fp){	if (fp)	{		unzCloseCurrentFile(fp);		unzClose(fp);	}}void printZipPackageContent(const char* strZipPackage){	unzFile fp = unzOpen(strZipPackage);	if (fp == 0) return;	bool more_files = true;	unzGoToFirstFile(fp);	while (more_files)	{		char strFileName[256];		unz_file_info finfo;		// holds some info about the file		unzGetCurrentFileInfo(fp,&finfo,strFileName,256,NULL,0,NULL,0);		more_files = (unzGoToNextFile(fp) == UNZ_OK);		printf("%s\n",strFileName);	}}

to read from a zip file, simply use "unzReadCurrentFile"

flangazor

106

flangazor

Nov 24, 2004 at 1:44 PM

zlib has been discussed in the forum many many times. Try the forum search located in the top right hand of the page. It's pretty useful!

gl hf

fiskbil

Nov 24, 2004 at 2:23 PM

I find zziplib very handy, it wraps zlib into easy to use (although C-ish) calls. It can be found here.

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