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/*
* Compress input and feed it to a block-oriented back end.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <inttypes.h>
#include <stdbool.h>
#include <zlib.h>
#include "backend.h"
int init_data(struct backend *be, const char *argv[])
{
be->outbuf = malloc(be->blocksize);
if (!be->outbuf)
return -1;
if (be->open(be, argv))
return -1;
memset(&be->zstream, 0, sizeof be->zstream);
be->zstream.next_out = (void *)be->outbuf;
be->zstream.avail_out = be->blocksize;
/* Initialize a gzip data stream */
if (deflateInit2(&be->zstream, 9, Z_DEFLATED,
16+15, 9, Z_DEFAULT_STRATEGY) < 0)
return -1;
return 0;
}
int write_data(struct backend *be, const void *buf, size_t len, bool flush)
{
int rv = Z_OK;
be->zstream.next_in = buf;
be->zstream.avail_in = len;
while (be->zstream.avail_in || (flush && rv == Z_OK)) {
rv = deflate(&be->zstream, flush ? Z_FINISH : Z_NO_FLUSH);
if (be->zstream.avail_out == 0) {
if (be->write(be, be->outbuf, be->blocksize))
return -1;
be->zstream.next_out = (void *)be->outbuf;
be->zstream.avail_out = be->blocksize;
}
if (rv == Z_STREAM_ERROR)
return -1;
}
if (flush) {
/* Output the last (fractional) packet... may be zero */
if (be->write(be, be->outbuf, be->blocksize - be->zstream.avail_out))
return -1;
free(be->outbuf);
}
return 0;
}
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