/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

/***
  This file is part of systemd.

  Copyright 2015 Lennart Poettering

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 of the License, or
  (at your option) any later version.

  systemd is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include "util.h"
#include "import-compress.h"

void import_compress_free(ImportCompress *c) {
        assert(c);

        if (c->type == IMPORT_COMPRESS_XZ)
                lzma_end(&c->xz);
        else if (c->type == IMPORT_COMPRESS_GZIP)
                inflateEnd(&c->gzip);
        else if (c->type == IMPORT_COMPRESS_BZIP2)
                BZ2_bzDecompressEnd(&c->bzip2);

        c->type = IMPORT_COMPRESS_UNKNOWN;
}

int import_uncompress_detect(ImportCompress *c, const void *data, size_t size) {
        static const uint8_t xz_signature[] = {
                0xfd, '7', 'z', 'X', 'Z', 0x00
        };
        static const uint8_t gzip_signature[] = {
                0x1f, 0x8b
        };
        static const uint8_t bzip2_signature[] = {
                'B', 'Z', 'h'
        };

        int r;

        assert(c);

        if (c->type != IMPORT_COMPRESS_UNKNOWN)
                return 1;

        if (size < MAX3(sizeof(xz_signature),
                        sizeof(gzip_signature),
                        sizeof(bzip2_signature)))
                return 0;

        assert(data);

        if (memcmp(data, xz_signature, sizeof(xz_signature)) == 0) {
                lzma_ret xzr;

                xzr = lzma_stream_decoder(&c->xz, UINT64_MAX, LZMA_TELL_UNSUPPORTED_CHECK);
                if (xzr != LZMA_OK)
                        return -EIO;

                c->type = IMPORT_COMPRESS_XZ;

        } else if (memcmp(data, gzip_signature, sizeof(gzip_signature)) == 0) {
                r = inflateInit2(&c->gzip, 15+16);
                if (r != Z_OK)
                        return -EIO;

                c->type = IMPORT_COMPRESS_GZIP;

        } else if (memcmp(data, bzip2_signature, sizeof(bzip2_signature)) == 0) {
                r = BZ2_bzDecompressInit(&c->bzip2, 0, 0);
                if (r != BZ_OK)
                        return -EIO;

                c->type = IMPORT_COMPRESS_BZIP2;
        } else
                c->type = IMPORT_COMPRESS_UNCOMPRESSED;

        return 1;
}

int import_uncompress(ImportCompress *c, const void *data, size_t size, ImportCompressCallback callback, void *userdata) {
        int r;

        assert(c);
        assert(callback);

        r = import_uncompress_detect(c, data, size);
        if (r <= 0)
                return r;

        if (size <= 0)
                return 1;

        assert(data);

        switch (c->type) {

        case IMPORT_COMPRESS_UNCOMPRESSED:
                r = callback(data, size, userdata);
                if (r < 0)
                        return r;

                break;

        case IMPORT_COMPRESS_XZ:
                c->xz.next_in = data;
                c->xz.avail_in = size;

                while (c->xz.avail_in > 0) {
                        uint8_t buffer[16 * 1024];
                        lzma_ret lzr;

                        c->xz.next_out = buffer;
                        c->xz.avail_out = sizeof(buffer);

                        lzr = lzma_code(&c->xz, LZMA_RUN);
                        if (lzr != LZMA_OK && lzr != LZMA_STREAM_END)
                                return -EIO;

                        r = callback(buffer, sizeof(buffer) - c->xz.avail_out, userdata);
                        if (r < 0)
                                return r;
                }

                break;

        case IMPORT_COMPRESS_GZIP:
                c->gzip.next_in = (void*) data;
                c->gzip.avail_in = size;

                while (c->gzip.avail_in > 0) {
                        uint8_t buffer[16 * 1024];

                        c->gzip.next_out = buffer;
                        c->gzip.avail_out = sizeof(buffer);

                        r = inflate(&c->gzip, Z_NO_FLUSH);
                        if (r != Z_OK && r != Z_STREAM_END)
                                return -EIO;

                        r = callback(buffer, sizeof(buffer) - c->gzip.avail_out, userdata);
                        if (r < 0)
                                return r;
                }

                break;

        case IMPORT_COMPRESS_BZIP2:
                c->bzip2.next_in = (void*) data;
                c->bzip2.avail_in = size;

                while (c->bzip2.avail_in > 0) {
                        uint8_t buffer[16 * 1024];

                        c->bzip2.next_out = (char*) buffer;
                        c->bzip2.avail_out = sizeof(buffer);

                        r = BZ2_bzDecompress(&c->bzip2);
                        if (r != BZ_OK && r != BZ_STREAM_END)
                                return -EIO;

                        r = callback(buffer, sizeof(buffer) - c->bzip2.avail_out, userdata);
                        if (r < 0)
                                return r;
                }

                break;

        default:
                assert_not_reached("Unknown compression");
        }

        return 1;
}

static const char* const import_compress_type_table[_IMPORT_COMPRESS_TYPE_MAX] = {
        [IMPORT_COMPRESS_UNKNOWN] = "unknown",
        [IMPORT_COMPRESS_UNCOMPRESSED] = "uncompressed",
        [IMPORT_COMPRESS_XZ] = "xz",
        [IMPORT_COMPRESS_GZIP] = "gzip",
        [IMPORT_COMPRESS_BZIP2] = "bzip2",
};

DEFINE_STRING_TABLE_LOOKUP(import_compress_type, ImportCompressType);