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/* SPDX-License-Identifier: GPL-3.0-or-later */
/*
* gzip.c
*
* Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
*/
#include "../internal.h"
#include <zlib.h>
typedef struct {
ostream_comp_t base;
z_stream strm;
} ostream_gzip_t;
static int flush_inbuf(ostream_comp_t *base, bool finish)
{
ostream_gzip_t *gzip = (ostream_gzip_t *)base;
size_t have;
int ret;
if (sizeof(size_t) > sizeof(uInt)) {
gzip->strm.avail_in = ~((uInt)0);
if ((size_t)gzip->strm.avail_in > base->inbuf_used)
gzip->strm.avail_in = (uInt)base->inbuf_used;
} else {
gzip->strm.avail_in = (uInt)base->inbuf_used;
}
gzip->strm.next_in = base->inbuf;
do {
gzip->strm.avail_out = BUFSZ;
gzip->strm.next_out = base->outbuf;
ret = deflate(&gzip->strm, finish ? Z_FINISH : Z_NO_FLUSH);
if (ret == Z_STREAM_ERROR) {
fprintf(stderr,
"%s: internal error in gzip compressor.\n",
base->wrapped->get_filename(base->wrapped));
return -1;
}
have = BUFSZ - gzip->strm.avail_out;
if (base->wrapped->append(base->wrapped, base->outbuf, have))
return -1;
} while (gzip->strm.avail_out == 0);
base->inbuf_used = 0;
return 0;
}
static void cleanup(ostream_comp_t *base)
{
ostream_gzip_t *gzip = (ostream_gzip_t *)base;
deflateEnd(&gzip->strm);
}
ostream_comp_t *ostream_gzip_create(const char *filename)
{
ostream_gzip_t *gzip = calloc(1, sizeof(*gzip));
ostream_comp_t *base = (ostream_comp_t *)gzip;
int ret;
if (gzip == NULL) {
fprintf(stderr, "%s: creating gzip wrapper: %s.\n",
filename, strerror(errno));
return NULL;
}
ret = deflateInit2(&gzip->strm, 9, Z_DEFLATED, 16 + 15, 8,
Z_DEFAULT_STRATEGY);
if (ret != Z_OK) {
fprintf(stderr,
"%s: internal error creating gzip compressor.\n",
filename);
free(gzip);
return NULL;
}
base->flush_inbuf = flush_inbuf;
base->cleanup = cleanup;
return base;
}
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