/*-
 * Copyright (c) 2003-2007 Tim Kientzle
 * All rights reserved.
 *
 * 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 AUTHOR(S) ``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 AUTHOR(S) 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.
 */

#include "archive_platform.h"

__FBSDID("$FreeBSD: src/lib/libarchive/archive_read_support_compression_bzip2.c,v 1.19 2008/12/06 06:45:15 kientzle Exp $");

#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#include <stdio.h>
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_BZLIB_H
#include <bzlib.h>
#endif

#include "archive.h"
#include "archive_private.h"
#include "archive_read_private.h"

#if HAVE_BZLIB_H
struct private_data {
    bz_stream    stream;
    char        *out_block;
    size_t       out_block_size;
    char         valid; /* True = decompressor is initialized */
    char         eof; /* True = found end of compressed data. */
};

/* Bzip2 filter */
static ssize_t  bzip2_filter_read(struct archive_read_filter *, const void **);
static int  bzip2_filter_close(struct archive_read_filter *);
#endif

/*
 * Note that we can detect bzip2 archives even if we can't decompress
 * them.  (In fact, we like detecting them because we can give better
 * error messages.)  So the bid framework here gets compiled even
 * if bzlib is unavailable.
 */
static int  bzip2_reader_bid(struct archive_read_filter_bidder *, struct archive_read_filter *);
static int  bzip2_reader_init(struct archive_read_filter *);
static int  bzip2_reader_free(struct archive_read_filter_bidder *);

int
archive_read_support_compression_bzip2(struct archive *_a)
{
    struct archive_read *a = (struct archive_read *)_a;
    struct archive_read_filter_bidder *reader = __archive_read_get_bidder(a);

    if (reader == NULL)
        return (ARCHIVE_FATAL);

    reader->data = NULL;
    reader->bid = bzip2_reader_bid;
    reader->init = bzip2_reader_init;
    reader->options = NULL;
    reader->free = bzip2_reader_free;
#if HAVE_BZLIB_H
    return (ARCHIVE_OK);
#else
    archive_set_error(_a, ARCHIVE_ERRNO_MISC,
        "Using external bunzip2 program");
    return (ARCHIVE_WARN);
#endif
}

static int
bzip2_reader_free(struct archive_read_filter_bidder *self){
    (void)self; /* UNUSED */
    return (ARCHIVE_OK);
}

/*
 * Test whether we can handle this data.
 *
 * This logic returns zero if any part of the signature fails.  It
 * also tries to Do The Right Thing if a very short buffer prevents us
 * from verifying as much as we would like.
 */
static int
bzip2_reader_bid(struct archive_read_filter_bidder *self, struct archive_read_filter *filter)
{
    const unsigned char *buffer;
    ssize_t avail;
    int bits_checked;

    (void)self; /* UNUSED */

    /* Minimal bzip2 archive is 14 bytes. */
    buffer = __archive_read_filter_ahead(filter, 14, &avail);
    if (buffer == NULL)
        return (0);

    /* First three bytes must be "BZh" */
    bits_checked = 0;
    if (buffer[0] != 'B' || buffer[1] != 'Z' || buffer[2] != 'h')
        return (0);
    bits_checked += 24;

    /* Next follows a compression flag which must be an ASCII digit. */
    if (buffer[3] < '1' || buffer[3] > '9')
        return (0);
    bits_checked += 5;

    /* After BZh[1-9], there must be either a data block
     * which begins with 0x314159265359 or an end-of-data
     * marker of 0x177245385090. */
    if (memcmp(buffer + 4, "\x31\x41\x59\x26\x53\x59", 6) == 0)
        bits_checked += 48;
    else if (memcmp(buffer + 4, "\x17\x72\x45\x38\x50\x90", 6) == 0)
        bits_checked += 48;
    else
        return (0);

    return (bits_checked);
}

#ifndef HAVE_BZLIB_H

/*
 * If we don't have the library on this system, we can't actually do the
 * decompression.  We can, however, still detect compressed archives
 * and emit a useful message.
 */
static int
bzip2_reader_init(struct archive_read_filter *self)
{
    int r;

    r = __archive_read_program(self, "bunzip2");
    /* Note: We set the format here even if __archive_read_program()
     * above fails.  We do, after all, know what the format is
     * even if we weren't able to read it. */
    self->code = ARCHIVE_COMPRESSION_BZIP2;
    self->name = "bzip2";
    return (r);
}


#else

/*
 * Setup the callbacks.
 */
static int
bzip2_reader_init(struct archive_read_filter *self)
{
    static const size_t out_block_size = 64 * 1024;
    void *out_block;
    struct private_data *state;

    self->code = ARCHIVE_COMPRESSION_BZIP2;
    self->name = "bzip2";

    state = (struct private_data *)calloc(sizeof(*state), 1);
    out_block = (unsigned char *)malloc(out_block_size);
    if (self == NULL || state == NULL || out_block == NULL) {
        archive_set_error(&self->archive->archive, ENOMEM,
            "Can't allocate data for bzip2 decompression");
        free(out_block);
        free(state);
        return (ARCHIVE_FATAL);
    }

    self->data = state;
    state->out_block_size = out_block_size;
    state->out_block = out_block;
    self->read = bzip2_filter_read;
    self->skip = NULL; /* not supported */
    self->close = bzip2_filter_close;

    return (ARCHIVE_OK);
}

/*
 * Return the next block of decompressed data.
 */
static ssize_t
bzip2_filter_read(struct archive_read_filter *self, const void **p)
{
    struct private_data *state;
    size_t read_avail, decompressed;
    const char *read_buf;
    ssize_t ret;

    state = (struct private_data *)self->data;
    read_avail = 0;

    if (state->eof) {
        *p = NULL;
        return (0);
    }

    /* Empty our output buffer. */
    state->stream.next_out = state->out_block;
    state->stream.avail_out = state->out_block_size;

    /* Try to fill the output buffer. */
    for (;;) {
        if (!state->valid) {
            if (bzip2_reader_bid(self->bidder, self->upstream) == 0) {
                state->eof = 1;
                *p = state->out_block;
                decompressed = state->stream.next_out
                    - state->out_block;
                return (decompressed);
            }
            /* Initialize compression library. */
            ret = BZ2_bzDecompressInit(&(state->stream),
                       0 /* library verbosity */,
                       0 /* don't use low-mem algorithm */);

            /* If init fails, try low-memory algorithm instead. */
            if (ret == BZ_MEM_ERROR)
                ret = BZ2_bzDecompressInit(&(state->stream),
                       0 /* library verbosity */,
                       1 /* do use low-mem algo */);

            if (ret != BZ_OK) {
                const char *detail = NULL;
                int err = ARCHIVE_ERRNO_MISC;
                switch (ret) {
                case BZ_PARAM_ERROR:
                    detail = "invalid setup parameter";
                    break;
                case BZ_MEM_ERROR:
                    err = ENOMEM;
                    detail = "out of memory";
                    break;
                case BZ_CONFIG_ERROR:
                    detail = "mis-compiled library";
                    break;
                }
                archive_set_error(&self->archive->archive, err,
                    "Internal error initializing decompressor%s%s",
                    detail == NULL ? "" : ": ",
                    detail);
                return (ARCHIVE_FATAL);
            }
            state->valid = 1;
        }

        /* stream.next_in is really const, but bzlib
         * doesn't declare it so. <sigh> */
        read_buf =
            __archive_read_filter_ahead(self->upstream, 1, &ret);
        if (read_buf == NULL)
            return (ARCHIVE_FATAL);
        state->stream.next_in = (char *)(uintptr_t)read_buf;
        state->stream.avail_in = ret;
        /* There is no more data, return whatever we have. */
        if (ret == 0) {
            state->eof = 1;
            *p = state->out_block;
            decompressed = state->stream.next_out
                - state->out_block;
            return (decompressed);
        }

        /* Decompress as much as we can in one pass. */
        ret = BZ2_bzDecompress(&(state->stream));
        __archive_read_filter_consume(self->upstream,
            state->stream.next_in - read_buf);

        switch (ret) {
        case BZ_STREAM_END: /* Found end of stream. */
            switch (BZ2_bzDecompressEnd(&(state->stream))) {
            case BZ_OK:
                break;
            default:
                archive_set_error(&(self->archive->archive),
                      ARCHIVE_ERRNO_MISC,
                      "Failed to clean up decompressor");
                return (ARCHIVE_FATAL);
            }
            state->valid = 0;
            /* FALLTHROUGH */
        case BZ_OK: /* Decompressor made some progress. */
            /* If we filled our buffer, update stats and return. */
            if (state->stream.avail_out == 0) {
                *p = state->out_block;
                decompressed = state->stream.next_out
                    - state->out_block;
                return (decompressed);
            }
            break;
        default: /* Return an error. */
            archive_set_error(&self->archive->archive,
                ARCHIVE_ERRNO_MISC, "bzip decompression failed");
            return (ARCHIVE_FATAL);
        }
    }
}

/*
 * Clean up the decompressor.
 */
static int
bzip2_filter_close(struct archive_read_filter *self)
{
    struct private_data *state;
    int ret = ARCHIVE_OK;

    state = (struct private_data *)self->data;

    if (state->valid) {
        switch (BZ2_bzDecompressEnd(&state->stream)) {
        case BZ_OK:
            break;
        default:
            archive_set_error(&self->archive->archive,
                      ARCHIVE_ERRNO_MISC,
                      "Failed to clean up decompressor");
            ret = ARCHIVE_FATAL;
        }
    }

    free(state->out_block);
    free(state);
    return (ARCHIVE_OK);
}

#endif /* HAVE_BZLIB_H */
