/*      $NetBSD: unbzip2.c,v 1.14 2017/08/04 07:27:08 mrg Exp $ */

/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2006 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Simon Burge.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/* This file is #included by gzip.c */

static off_t
unbzip2(int in, int out, char *pre, size_t prelen, off_t *bytes_in)
{
        int             ret, end_of_file, cold = 0;
        off_t           bytes_out = 0;
        bz_stream       bzs;
        static char     *inbuf, *outbuf;

        if (inbuf == NULL)
                inbuf = malloc(BUFLEN);
        if (outbuf == NULL)
                outbuf = malloc(BUFLEN);
        if (inbuf == NULL || outbuf == NULL)
                maybe_err("malloc");

        bzs.bzalloc = NULL;
        bzs.bzfree = NULL;
        bzs.opaque = NULL;

        end_of_file = 0;
        ret = BZ2_bzDecompressInit(&bzs, 0, 0);
        if (ret != BZ_OK)
                maybe_errx("bzip2 init");

        /* Prepend. */
        bzs.avail_in = prelen;
        bzs.next_in = pre;

        if (bytes_in)
                *bytes_in = prelen;

        while (ret == BZ_OK) {
                check_siginfo();
                if (bzs.avail_in == 0 && !end_of_file) {
                        ssize_t n;

                        n = read(in, inbuf, BUFLEN);
                        if (n < 0)
                                maybe_err("read");
                        if (n == 0)
                                end_of_file = 1;
                        infile_newdata(n);
                        bzs.next_in = inbuf;
                        bzs.avail_in = n;
                        if (bytes_in)
                                *bytes_in += n;
                }

                bzs.next_out = outbuf;
                bzs.avail_out = BUFLEN;
                ret = BZ2_bzDecompress(&bzs);

                switch (ret) {
                case BZ_STREAM_END:
                case BZ_OK:
                        if (ret == BZ_OK && end_of_file) {
                                /*
                                 * If we hit this after a stream end, consider
                                 * it as the end of the whole file and don't
                                 * bail out.
                                 */
                                if (cold == 1)
                                        ret = BZ_STREAM_END;
                                else
                                        maybe_errx("truncated file");
                        }
                        cold = 0;
                        if (!tflag && bzs.avail_out != BUFLEN) {
                                ssize_t n;

                                n = write(out, outbuf, BUFLEN - bzs.avail_out);
                                if (n < 0)
                                        maybe_err("write");
                                bytes_out += n;
                        }
                        if (ret == BZ_STREAM_END && !end_of_file) {
                                if (BZ2_bzDecompressEnd(&bzs) != BZ_OK ||
                                    BZ2_bzDecompressInit(&bzs, 0, 0) != BZ_OK)
                                        maybe_errx("bzip2 re-init");
                                cold = 1;
                                ret = BZ_OK;
                        }
                        break;

                case BZ_DATA_ERROR:
                        maybe_warnx("bzip2 data integrity error");
                        break;

                case BZ_DATA_ERROR_MAGIC:
                        maybe_warnx("bzip2 magic number error");
                        break;

                case BZ_MEM_ERROR:
                        maybe_warnx("bzip2 out of memory");
                        break;
                
                default:        
                        maybe_warnx("unknown bzip2 error: %d", ret);
                        break;
                }
        }

        if (ret != BZ_STREAM_END || BZ2_bzDecompressEnd(&bzs) != BZ_OK)
                return (-1);

        return (bytes_out);
}