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      1 /*-
      2  * SPDX-License-Identifier: BSD-2-Clause
      3  *
      4  * Copyright (c) 2022 Klara, Inc.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     25  * SUCH DAMAGE.
     26  */
     27 
     28 /* This file is #included by gzip.c */
     29 
     30 static off_t
     31 unzstd(int in, int out, char *pre, size_t prelen, off_t *bytes_in)
     32 {
     33 	static char *ibuf, *obuf;
     34 	ZSTD_inBuffer zib;
     35 	ZSTD_outBuffer zob;
     36 	ZSTD_DCtx *zds;
     37 	ssize_t res;
     38 	size_t zres;
     39 	size_t bytes_out = 0;
     40 	int eof = 0;
     41 
     42 	if (ibuf == NULL)
     43 		ibuf = malloc(BUFLEN);
     44 	if (obuf == NULL)
     45 		obuf = malloc(BUFLEN);
     46 	if (ibuf == NULL || obuf == NULL)
     47 		maybe_err("malloc");
     48 
     49 	zds = ZSTD_createDStream();
     50 	ZSTD_initDStream(zds);
     51 
     52 	zib.src = pre;
     53 	zib.size = prelen;
     54 	zib.pos = 0;
     55 	if (bytes_in != NULL)
     56 		*bytes_in = prelen;
     57 	zob.dst = obuf;
     58 	zob.size = BUFLEN;
     59 	zob.pos = 0;
     60 
     61 	while (!eof) {
     62 		if (zib.pos >= zib.size) {
     63 			res = read(in, ibuf, BUFLEN);
     64 			if (res < 0)
     65 				maybe_err("read");
     66 			if (res == 0)
     67 				eof = 1;
     68 			infile_newdata(res);
     69 			zib.src = ibuf;
     70 			zib.size = res;
     71 			zib.pos = 0;
     72 			if (bytes_in != NULL)
     73 				*bytes_in += res;
     74 		}
     75 		zres = ZSTD_decompressStream(zds, &zob, &zib);
     76 		if (ZSTD_isError(zres)) {
     77 			maybe_errx("%s", ZSTD_getErrorName(zres));
     78 		}
     79 		if (zob.pos > 0) {
     80 			res = write(out, obuf, zob.pos);
     81 			if (res < 0)
     82 				maybe_err("write");
     83 			zob.pos = 0;
     84 			bytes_out += res;
     85 		}
     86 	}
     87 	ZSTD_freeDStream(zds);
     88 	return (bytes_out);
     89 }
     90