Name

deflateCopy — Copies the compression state information in source to the uninitialized z_stream structure referenced by dest.

Library

Libz.lib

Synopsis

#include <zlib.h>
int deflateCopy(z_streamp dest, z_streamp source);

Return Value

On success, deflateCopy() shall return Z_OK. Otherwise it shall return a value less than zero to indicate the error.

Detailed Description

The deflateCopy() function shall copy the compression state information in source to the uninitialized z_stream structure referenced by dest.

On successful return, dest will be an exact copy of the stream referenced by source. The input and output buffer pointers in next_in and next_out will reference the same data.

Examples

To copy the compression state information in source to the uninitialized z_stream structure referenced by dest.

#include <stdio.h> 
#include <zlib.h>

void Deflatecopy( )

{
    uLong sourceLen = (uLong)strlen(hello)+1; 
    z_stream stream; 
    z_stream stream1; 
    Byte *compr, *uncompr; 
    Bytef *dest,  uLongf *destLen ; 
    uLong comprLen = 20*sizeof(int);  
    uLong uncomprLen = comprLen; 
    int level=Z_DEFAULT_COMPRESSION; 
    const char hello[] = "hello, hello!"; 
    compr = (Byte*)calloc((uInt)comprLen, 1); 
    uncompr = (Byte*)calloc((uInt)uncomprLen, 1); 
    
    stream.zalloc = (alloc_func)0; 
    stream.zfree = (free_func)0; 
    stream.opaque = (voidpf)0; 
    stream.next_in = (Bytef*)hello; 
    stream.avail_in = (uInt)sourceLen; 
    stream.next_out = dest; 
    stream.avail_out = (uInt)*destLen; 
  
    deflateInit(&stream, level); 
    deflateCopy(&stream1 , &stream);  
    deflateEnd(&stream); 
}

Output

Now stream1 and stream are in same state.

Errors

On error, deflateCopy() shall return a value as described below:

`Z_STREAM_ERROR`		The state in source is inconsistent, or either source or dest was `NULL`.
`Z_MEM_ERROR`		Insufficient memory available.

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