/*-
 * Copyright (c) 2004 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_format_zip.c,v 1.28 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
#include <time.h>
#ifdef HAVE_ZLIB_H
#include <cm_zlib.h>
#endif

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

#ifndef HAVE_ZLIB_H
#include "archive_crc32.h"
#endif

struct zip {
    /* entry_bytes_remaining is the number of bytes we expect. */
    int64_t         entry_bytes_remaining;
    int64_t         entry_offset;

    /* These count the number of bytes actually read for the entry. */
    int64_t         entry_compressed_bytes_read;
    int64_t         entry_uncompressed_bytes_read;

    /* Running CRC32 of the decompressed data */
    unsigned long       entry_crc32;

    unsigned        version;
    unsigned        system;
    unsigned        flags;
    unsigned        compression;
    const char *        compression_name;
    time_t          mtime;
    time_t          ctime;
    time_t          atime;
    mode_t          mode;
    uid_t           uid;
    gid_t           gid;

    /* Flags to mark progress of decompression. */
    char            decompress_init;
    char            end_of_entry;

    unsigned long       crc32;
    ssize_t         filename_length;
    ssize_t         extra_length;
    int64_t         uncompressed_size;
    int64_t         compressed_size;

    unsigned char       *uncompressed_buffer;
    size_t          uncompressed_buffer_size;
#ifdef HAVE_ZLIB_H
    z_stream        stream;
    char            stream_valid;
#endif

    struct archive_string   pathname;
    struct archive_string   extra;
    char    format_name[64];
};

#define ZIP_LENGTH_AT_END   8

struct zip_file_header {
    char    signature[4];
    char    version[2];
    char    flags[2];
    char    compression[2];
    char    timedate[4];
    char    crc32[4];
    char    compressed_size[4];
    char    uncompressed_size[4];
    char    filename_length[2];
    char    extra_length[2];
};

static const char *compression_names[] = {
    "uncompressed",
    "shrinking",
    "reduced-1",
    "reduced-2",
    "reduced-3",
    "reduced-4",
    "imploded",
    "reserved",
    "deflation"
};

static int  archive_read_format_zip_bid(struct archive_read *);
static int  archive_read_format_zip_cleanup(struct archive_read *);
static int  archive_read_format_zip_read_data(struct archive_read *,
            const void **, size_t *, off_t *);
static int  archive_read_format_zip_read_data_skip(struct archive_read *a);
static int  archive_read_format_zip_read_header(struct archive_read *,
            struct archive_entry *);
static int  zip_read_data_deflate(struct archive_read *a, const void **buff,
            size_t *size, off_t *offset);
static int  zip_read_data_none(struct archive_read *a, const void **buff,
            size_t *size, off_t *offset);
static int  zip_read_file_header(struct archive_read *a,
            struct archive_entry *entry, struct zip *zip);
static time_t   zip_time(const char *);
static void process_extra(const void* extra, struct zip* zip);

int
archive_read_support_format_zip(struct archive *_a)
{
    struct archive_read *a = (struct archive_read *)_a;
    struct zip *zip;
    int r;

    zip = (struct zip *)malloc(sizeof(*zip));
    if (zip == NULL) {
        archive_set_error(&a->archive, ENOMEM, "Can't allocate zip data");
        return (ARCHIVE_FATAL);
    }
    memset(zip, 0, sizeof(*zip));

    r = __archive_read_register_format(a,
        zip,
        "zip",
        archive_read_format_zip_bid,
        NULL,
        archive_read_format_zip_read_header,
        archive_read_format_zip_read_data,
        archive_read_format_zip_read_data_skip,
        archive_read_format_zip_cleanup);

    if (r != ARCHIVE_OK)
        free(zip);
    return (ARCHIVE_OK);
}


static int
archive_read_format_zip_bid(struct archive_read *a)
{
    const char *p;
    const void *buff;
    ssize_t bytes_avail, offset;

    if ((p = __archive_read_ahead(a, 4, NULL)) == NULL)
        return (-1);

    /*
     * Bid of 30 here is: 16 bits for "PK",
     * next 16-bit field has four options (-2 bits).
     * 16 + 16-2 = 30.
     */
    if (p[0] == 'P' && p[1] == 'K') {
        if ((p[2] == '\001' && p[3] == '\002')
            || (p[2] == '\003' && p[3] == '\004')
            || (p[2] == '\005' && p[3] == '\006')
            || (p[2] == '\007' && p[3] == '\010')
            || (p[2] == '0' && p[3] == '0'))
            return (30);
    }

    /*
     * Attempt to handle self-extracting archives
     * by noting a PE header and searching forward
     * up to 128k for a 'PK\003\004' marker.
     */
    if (p[0] == 'M' && p[1] == 'Z') {
        /*
         * TODO: Optimize by initializing 'offset' to an
         * estimate of the likely start of the archive data
         * based on values in the PE header.  Note that we
         * don't need to be exact, but we mustn't skip too
         * far.  The search below will compensate if we
         * undershoot.
         */
        offset = 0;
        while (offset < 124000) {
            /* Get 4k of data beyond where we stopped. */
            buff = __archive_read_ahead(a, offset + 4096,
                &bytes_avail);
            if (bytes_avail < offset + 1)
                break;
            p = (const char *)buff + offset;
            while (p + 9 < (const char *)buff + bytes_avail) {
                if (p[0] == 'P' && p[1] == 'K' /* signature */
                    && p[2] == 3 && p[3] == 4 /* File entry */
                    && p[8] == 8 /* compression == deflate */
                    && p[9] == 0 /* High byte of compression */
                    )
                {
                    return (30);
                }
                ++p;
            }
            offset = p - (const char *)buff;
        }
    }

    return (0);
}

/*
 * Search forward for a "PK\003\004" file header.  This handles the
 * case of self-extracting archives, where there is an executable
 * prepended to the ZIP archive.
 */
static int
skip_sfx(struct archive_read *a)
{
    const void *h;
    const char *p, *q;
    size_t skip;
    ssize_t bytes;

    /*
     * TODO: We should be able to skip forward by a bunch
     * by lifting some values from the PE header.  We don't
     * need to be exact (we're still going to search forward
     * to find the header), but it will speed things up and
     * reduce the chance of a false positive.
     */
    for (;;) {
        h = __archive_read_ahead(a, 4, &bytes);
        if (bytes < 4)
            return (ARCHIVE_FATAL);
        p = h;
        q = p + bytes;

        /*
         * Scan ahead until we find something that looks
         * like the zip header.
         */
        while (p + 4 < q) {
            switch (p[3]) {
            case '\004':
                /* TODO: Additional verification here. */
                if (memcmp("PK\003\004", p, 4) == 0) {
                    skip = p - (const char *)h;
                    __archive_read_consume(a, skip);
                    return (ARCHIVE_OK);
                }
                p += 4;
                break;
            case '\003': p += 1; break;
            case 'K': p += 2; break;
            case 'P': p += 3; break;
            default: p += 4; break;
            }
        }
        skip = p - (const char *)h;
        __archive_read_consume(a, skip);
    }
}

static int
archive_read_format_zip_read_header(struct archive_read *a,
    struct archive_entry *entry)
{
    const void *h;
    const char *signature;
    struct zip *zip;
    int r = ARCHIVE_OK, r1;

    a->archive.archive_format = ARCHIVE_FORMAT_ZIP;
    if (a->archive.archive_format_name == NULL)
        a->archive.archive_format_name = "ZIP";

    zip = (struct zip *)(a->format->data);
    zip->decompress_init = 0;
    zip->end_of_entry = 0;
    zip->entry_uncompressed_bytes_read = 0;
    zip->entry_compressed_bytes_read = 0;
    zip->entry_crc32 = crc32(0, NULL, 0);
    if ((h = __archive_read_ahead(a, 4, NULL)) == NULL)
        return (ARCHIVE_FATAL);

    signature = (const char *)h;
    if (signature[0] == 'M' && signature[1] == 'Z') {
        /* This is an executable?  Must be self-extracting... */
        r = skip_sfx(a);
        if (r < ARCHIVE_WARN)
            return (r);
        if ((h = __archive_read_ahead(a, 4, NULL)) == NULL)
            return (ARCHIVE_FATAL);
        signature = (const char *)h;
    }

    if (signature[0] != 'P' || signature[1] != 'K') {
        archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
            "Bad ZIP file");
        return (ARCHIVE_FATAL);
    }

    /*
     * "PK00" signature is used for "split" archives that
     * only have a single segment.  This means we can just
     * skip the PK00; the first real file header should follow.
     */
    if (signature[2] == '0' && signature[3] == '0') {
        __archive_read_consume(a, 4);
        if ((h = __archive_read_ahead(a, 4, NULL)) == NULL)
            return (ARCHIVE_FATAL);
        signature = (const char *)h;
        if (signature[0] != 'P' || signature[1] != 'K') {
            archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
                "Bad ZIP file");
            return (ARCHIVE_FATAL);
        }
    }

    if (signature[2] == '\001' && signature[3] == '\002') {
        /* Beginning of central directory. */
        return (ARCHIVE_EOF);
    }

    if (signature[2] == '\003' && signature[3] == '\004') {
        /* Regular file entry. */
        r1 = zip_read_file_header(a, entry, zip);
        if (r1 != ARCHIVE_OK)
            return (r1);
        return (r);
    }

    if (signature[2] == '\005' && signature[3] == '\006') {
        /* End-of-archive record. */
        return (ARCHIVE_EOF);
    }

    if (signature[2] == '\007' && signature[3] == '\010') {
        /*
         * We should never encounter this record here;
         * see ZIP_LENGTH_AT_END handling below for details.
         */
        archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
            "Bad ZIP file: Unexpected end-of-entry record");
        return (ARCHIVE_FATAL);
    }

    archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
        "Damaged ZIP file or unsupported format variant (%d,%d)",
        signature[2], signature[3]);
    return (ARCHIVE_FATAL);
}

static int
zip_read_file_header(struct archive_read *a, struct archive_entry *entry,
    struct zip *zip)
{
    const struct zip_file_header *p;
    const void *h;

    if ((p = __archive_read_ahead(a, sizeof *p, NULL)) == NULL) {
        archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
            "Truncated ZIP file header");
        return (ARCHIVE_FATAL);
    }

    zip->version = p->version[0];
    zip->system = p->version[1];
    zip->flags = archive_le16dec(p->flags);
    zip->compression = archive_le16dec(p->compression);
    if (zip->compression <
        sizeof(compression_names)/sizeof(compression_names[0]))
        zip->compression_name = compression_names[zip->compression];
    else
        zip->compression_name = "??";
    zip->mtime = zip_time(p->timedate);
    zip->ctime = 0;
    zip->atime = 0;
    zip->mode = 0;
    zip->uid = 0;
    zip->gid = 0;
    zip->crc32 = archive_le32dec(p->crc32);
    zip->filename_length = archive_le16dec(p->filename_length);
    zip->extra_length = archive_le16dec(p->extra_length);
    zip->uncompressed_size = archive_le32dec(p->uncompressed_size);
    zip->compressed_size = archive_le32dec(p->compressed_size);

    __archive_read_consume(a, sizeof(struct zip_file_header));


    /* Read the filename. */
    if ((h = __archive_read_ahead(a, zip->filename_length, NULL)) == NULL) {
        archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
            "Truncated ZIP file header");
        return (ARCHIVE_FATAL);
    }
    if (archive_string_ensure(&zip->pathname, zip->filename_length) == NULL)
        __archive_errx(1, "Out of memory");
    archive_strncpy(&zip->pathname, h, zip->filename_length);
    __archive_read_consume(a, zip->filename_length);
    archive_entry_set_pathname(entry, zip->pathname.s);

    if (zip->pathname.s[archive_strlen(&zip->pathname) - 1] == '/')
        zip->mode = AE_IFDIR | 0777;
    else
        zip->mode = AE_IFREG | 0777;

    /* Read the extra data. */
    if ((h = __archive_read_ahead(a, zip->extra_length, NULL)) == NULL) {
        archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
            "Truncated ZIP file header");
        return (ARCHIVE_FATAL);
    }
    process_extra(h, zip);
    __archive_read_consume(a, zip->extra_length);

    /* Populate some additional entry fields: */
    archive_entry_set_mode(entry, zip->mode);
    archive_entry_set_uid(entry, zip->uid);
    archive_entry_set_gid(entry, zip->gid);
    archive_entry_set_mtime(entry, zip->mtime, 0);
    archive_entry_set_ctime(entry, zip->ctime, 0);
    archive_entry_set_atime(entry, zip->atime, 0);
    /* Set the size only if it's meaningful. */
    if (0 == (zip->flags & ZIP_LENGTH_AT_END))
        archive_entry_set_size(entry, zip->uncompressed_size);

    zip->entry_bytes_remaining = zip->compressed_size;
    zip->entry_offset = 0;

    /* If there's no body, force read_data() to return EOF immediately. */
    if (0 == (zip->flags & ZIP_LENGTH_AT_END)
        && zip->entry_bytes_remaining < 1)
        zip->end_of_entry = 1;

    /* Set up a more descriptive format name. */
    sprintf(zip->format_name, "ZIP %d.%d (%s)",
        zip->version / 10, zip->version % 10,
        zip->compression_name);
    a->archive.archive_format_name = zip->format_name;

    return (ARCHIVE_OK);
}

/* Convert an MSDOS-style date/time into Unix-style time. */
static time_t
zip_time(const char *p)
{
    int msTime, msDate;
    struct tm ts;

    msTime = (0xff & (unsigned)p[0]) + 256 * (0xff & (unsigned)p[1]);
    msDate = (0xff & (unsigned)p[2]) + 256 * (0xff & (unsigned)p[3]);

    memset(&ts, 0, sizeof(ts));
    ts.tm_year = ((msDate >> 9) & 0x7f) + 80; /* Years since 1900. */
    ts.tm_mon = ((msDate >> 5) & 0x0f) - 1; /* Month number. */
    ts.tm_mday = msDate & 0x1f; /* Day of month. */
    ts.tm_hour = (msTime >> 11) & 0x1f;
    ts.tm_min = (msTime >> 5) & 0x3f;
    ts.tm_sec = (msTime << 1) & 0x3e;
    ts.tm_isdst = -1;
    return mktime(&ts);
}

static int
archive_read_format_zip_read_data(struct archive_read *a,
    const void **buff, size_t *size, off_t *offset)
{
    int r;
    struct zip *zip;

    zip = (struct zip *)(a->format->data);

    /*
     * If we hit end-of-entry last time, clean up and return
     * ARCHIVE_EOF this time.
     */
    if (zip->end_of_entry) {
        *offset = zip->entry_uncompressed_bytes_read;
        *size = 0;
        *buff = NULL;
        return (ARCHIVE_EOF);
    }

    switch(zip->compression) {
    case 0:  /* No compression. */
        r =  zip_read_data_none(a, buff, size, offset);
        break;
    case 8: /* Deflate compression. */
        r =  zip_read_data_deflate(a, buff, size, offset);
        break;
    default: /* Unsupported compression. */
        *buff = NULL;
        *size = 0;
        *offset = 0;
        /* Return a warning. */
        archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
            "Unsupported ZIP compression method (%s)",
            zip->compression_name);
        if (zip->flags & ZIP_LENGTH_AT_END) {
            /*
             * ZIP_LENGTH_AT_END requires us to
             * decompress the entry in order to
             * skip it, but we don't know this
             * compression method, so we give up.
             */
            r = ARCHIVE_FATAL;
        } else {
            /* We can't decompress this entry, but we will
             * be able to skip() it and try the next entry. */
            r = ARCHIVE_WARN;
        }
        break;
    }
    if (r != ARCHIVE_OK)
        return (r);
    /* Update checksum */
    if (*size)
        zip->entry_crc32 = crc32(zip->entry_crc32, *buff, *size);
    /* If we hit the end, swallow any end-of-data marker. */
    if (zip->end_of_entry) {
        if (zip->flags & ZIP_LENGTH_AT_END) {
            const char *p;

            if ((p = __archive_read_ahead(a, 16, NULL)) == NULL) {
                archive_set_error(&a->archive,
                    ARCHIVE_ERRNO_FILE_FORMAT,
                    "Truncated ZIP end-of-file record");
                return (ARCHIVE_FATAL);
            }
            zip->crc32 = archive_le32dec(p + 4);
            zip->compressed_size = archive_le32dec(p + 8);
            zip->uncompressed_size = archive_le32dec(p + 12);
            __archive_read_consume(a, 16);
        }
        /* Check file size, CRC against these values. */
        if (zip->compressed_size != zip->entry_compressed_bytes_read) {
            archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
                "ZIP compressed data is wrong size");
            return (ARCHIVE_WARN);
        }
        /* Size field only stores the lower 32 bits of the actual size. */
        if ((zip->uncompressed_size & UINT32_MAX)
            != (zip->entry_uncompressed_bytes_read & UINT32_MAX)) {
            archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
                "ZIP uncompressed data is wrong size");
            return (ARCHIVE_WARN);
        }
        /* Check computed CRC against header */
        if (zip->crc32 != zip->entry_crc32) {
            archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
                "ZIP bad CRC: 0x%lx should be 0x%lx",
                zip->entry_crc32, zip->crc32);
            return (ARCHIVE_WARN);
        }
    }

    /* Return EOF immediately if this is a non-regular file. */
    if (AE_IFREG != (zip->mode & AE_IFMT))
        return (ARCHIVE_EOF);
    return (ARCHIVE_OK);
}

/*
 * Read "uncompressed" data.  According to the current specification,
 * if ZIP_LENGTH_AT_END is specified, then the size fields in the
 * initial file header are supposed to be set to zero.  This would, of
 * course, make it impossible for us to read the archive, since we
 * couldn't determine the end of the file data.  Info-ZIP seems to
 * include the real size fields both before and after the data in this
 * case (the CRC only appears afterwards), so this works as you would
 * expect.
 *
 * Returns ARCHIVE_OK if successful, ARCHIVE_FATAL otherwise, sets
 * zip->end_of_entry if it consumes all of the data.
 */
static int
zip_read_data_none(struct archive_read *a, const void **buff,
    size_t *size, off_t *offset)
{
    struct zip *zip;
    ssize_t bytes_avail;

    zip = (struct zip *)(a->format->data);

    if (zip->entry_bytes_remaining == 0) {
        *buff = NULL;
        *size = 0;
        *offset = zip->entry_offset;
        zip->end_of_entry = 1;
        return (ARCHIVE_OK);
    }
    /*
     * Note: '1' here is a performance optimization.
     * Recall that the decompression layer returns a count of
     * available bytes; asking for more than that forces the
     * decompressor to combine reads by copying data.
     */
    *buff = __archive_read_ahead(a, 1, &bytes_avail);
    if (bytes_avail <= 0) {
        archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
            "Truncated ZIP file data");
        return (ARCHIVE_FATAL);
    }
    if (bytes_avail > zip->entry_bytes_remaining)
        bytes_avail = zip->entry_bytes_remaining;
    __archive_read_consume(a, bytes_avail);
    *size = bytes_avail;
    *offset = zip->entry_offset;
    zip->entry_offset += *size;
    zip->entry_bytes_remaining -= *size;
    zip->entry_uncompressed_bytes_read += *size;
    zip->entry_compressed_bytes_read += *size;
    return (ARCHIVE_OK);
}

#ifdef HAVE_ZLIB_H
static int
zip_read_data_deflate(struct archive_read *a, const void **buff,
    size_t *size, off_t *offset)
{
    struct zip *zip;
    ssize_t bytes_avail;
    const void *compressed_buff;
    int r;

    zip = (struct zip *)(a->format->data);

    /* If the buffer hasn't been allocated, allocate it now. */
    if (zip->uncompressed_buffer == NULL) {
        zip->uncompressed_buffer_size = 32 * 1024;
        zip->uncompressed_buffer
            = (unsigned char *)malloc(zip->uncompressed_buffer_size);
        if (zip->uncompressed_buffer == NULL) {
            archive_set_error(&a->archive, ENOMEM,
                "No memory for ZIP decompression");
            return (ARCHIVE_FATAL);
        }
    }

    /* If we haven't yet read any data, initialize the decompressor. */
    if (!zip->decompress_init) {
        if (zip->stream_valid)
            r = inflateReset(&zip->stream);
        else
            r = inflateInit2(&zip->stream,
                -15 /* Don't check for zlib header */);
        if (r != Z_OK) {
            archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
                "Can't initialize ZIP decompression.");
            return (ARCHIVE_FATAL);
        }
        /* Stream structure has been set up. */
        zip->stream_valid = 1;
        /* We've initialized decompression for this stream. */
        zip->decompress_init = 1;
    }

    /*
     * Note: '1' here is a performance optimization.
     * Recall that the decompression layer returns a count of
     * available bytes; asking for more than that forces the
     * decompressor to combine reads by copying data.
     */
    compressed_buff = __archive_read_ahead(a, 1, &bytes_avail);
    if (bytes_avail <= 0) {
        archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
            "Truncated ZIP file body");
        return (ARCHIVE_FATAL);
    }

    /*
     * A bug in zlib.h: stream.next_in should be marked 'const'
     * but isn't (the library never alters data through the
     * next_in pointer, only reads it).  The result: this ugly
     * cast to remove 'const'.
     */
    zip->stream.next_in = (Bytef *)(uintptr_t)(const void *)compressed_buff;
    zip->stream.avail_in = bytes_avail;
    zip->stream.total_in = 0;
    zip->stream.next_out = zip->uncompressed_buffer;
    zip->stream.avail_out = zip->uncompressed_buffer_size;
    zip->stream.total_out = 0;

    r = inflate(&zip->stream, 0);
    switch (r) {
    case Z_OK:
        break;
    case Z_STREAM_END:
        zip->end_of_entry = 1;
        break;
    case Z_MEM_ERROR:
        archive_set_error(&a->archive, ENOMEM,
            "Out of memory for ZIP decompression");
        return (ARCHIVE_FATAL);
    default:
        archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
            "ZIP decompression failed (%d)", r);
        return (ARCHIVE_FATAL);
    }

    /* Consume as much as the compressor actually used. */
    bytes_avail = zip->stream.total_in;
    __archive_read_consume(a, bytes_avail);
    zip->entry_bytes_remaining -= bytes_avail;
    zip->entry_compressed_bytes_read += bytes_avail;

    *offset = zip->entry_offset;
    *size = zip->stream.total_out;
    zip->entry_uncompressed_bytes_read += *size;
    *buff = zip->uncompressed_buffer;
    zip->entry_offset += *size;
    return (ARCHIVE_OK);
}
#else
static int
zip_read_data_deflate(struct archive_read *a, const void **buff,
    size_t *size, off_t *offset)
{
    *buff = NULL;
    *size = 0;
    *offset = 0;
    archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
        "libarchive compiled without deflate support (no libz)");
    return (ARCHIVE_FATAL);
}
#endif

static int
archive_read_format_zip_read_data_skip(struct archive_read *a)
{
    struct zip *zip;
    const void *buff = NULL;
    off_t bytes_skipped;

    zip = (struct zip *)(a->format->data);

    /* If we've already read to end of data, we're done. */
    if (zip->end_of_entry)
        return (ARCHIVE_OK);

    /*
     * If the length is at the end, we have no choice but
     * to decompress all the data to find the end marker.
     */
    if (zip->flags & ZIP_LENGTH_AT_END) {
        size_t size;
        off_t offset;
        int r;
        do {
            r = archive_read_format_zip_read_data(a, &buff,
                &size, &offset);
        } while (r == ARCHIVE_OK);
        return (r);
    }

    /*
     * If the length is at the beginning, we can skip the
     * compressed data much more quickly.
     */
    bytes_skipped = __archive_read_skip(a, zip->entry_bytes_remaining);
    if (bytes_skipped < 0)
        return (ARCHIVE_FATAL);

    /* This entry is finished and done. */
    zip->end_of_entry = 1;
    return (ARCHIVE_OK);
}

static int
archive_read_format_zip_cleanup(struct archive_read *a)
{
    struct zip *zip;

    zip = (struct zip *)(a->format->data);
#ifdef HAVE_ZLIB_H
    if (zip->stream_valid)
        inflateEnd(&zip->stream);
#endif
    free(zip->uncompressed_buffer);
    archive_string_free(&(zip->pathname));
    archive_string_free(&(zip->extra));
    free(zip);
    (a->format->data) = NULL;
    return (ARCHIVE_OK);
}

/*
 * The extra data is stored as a list of
 *  id1+size1+data1 + id2+size2+data2 ...
 *  triplets.  id and size are 2 bytes each.
 */
static void
process_extra(const void* extra, struct zip* zip)
{
    int offset = 0;
    const char *p = (const char *)extra;
    while (offset < zip->extra_length - 4)
    {
        unsigned short headerid = archive_le16dec(p + offset);
        unsigned short datasize = archive_le16dec(p + offset + 2);
        offset += 4;
        if (offset + datasize > zip->extra_length)
            break;
#ifdef DEBUG
        fprintf(stderr, "Header id 0x%04x, length %d\n",
            headerid, datasize);
#endif
        switch (headerid) {
        case 0x0001:
            /* Zip64 extended information extra field. */
            if (datasize >= 8)
                zip->uncompressed_size = archive_le64dec(p + offset);
            if (datasize >= 16)
                zip->compressed_size = archive_le64dec(p + offset + 8);
            break;
        case 0x5455:
        {
            /* Extended time field "UT". */
            int flags = p[offset];
            offset++;
            datasize--;
            /* Flag bits indicate which dates are present. */
            if (flags & 0x01)
            {
#ifdef DEBUG
                fprintf(stderr, "mtime: %lld -> %d\n",
                    (long long)zip->mtime,
                    archive_le32dec(p + offset));
#endif
                if (datasize < 4)
                    break;
                zip->mtime = archive_le32dec(p + offset);
                offset += 4;
                datasize -= 4;
            }
            if (flags & 0x02)
            {
                if (datasize < 4)
                    break;
                zip->atime = archive_le32dec(p + offset);
                offset += 4;
                datasize -= 4;
            }
            if (flags & 0x04)
            {
                if (datasize < 4)
                    break;
                zip->ctime = archive_le32dec(p + offset);
                offset += 4;
                datasize -= 4;
            }
            break;
        }
        case 0x7855:
            /* Info-ZIP Unix Extra Field (type 2) "Ux". */
#ifdef DEBUG
            fprintf(stderr, "uid %d gid %d\n",
                archive_le16dec(p + offset),
                archive_le16dec(p + offset + 2));
#endif
            if (datasize >= 2)
                zip->uid = archive_le16dec(p + offset);
            if (datasize >= 4)
                zip->gid = archive_le16dec(p + offset + 2);
            break;
        default:
            break;
        }
        offset += datasize;
    }
#ifdef DEBUG
    if (offset != zip->extra_length)
    {
        fprintf(stderr,
            "Extra data field contents do not match reported size!");
    }
#endif
}
