// SPDX-License-Identifier: GPL-2.0-only
/*
 *  Copyright (C) 2018 Chelsio Communications.  All rights reserved.
 */

#include <linux/zlib.h>

#include "cxgb4.h"
#include "cudbg_if.h"
#include "cudbg_lib_common.h"
#include "cudbg_zlib.h"

static int cudbg_get_compress_hdr(struct cudbg_buffer *pdbg_buff,
                                  struct cudbg_buffer *pin_buff)
{
        if (pdbg_buff->offset + sizeof(struct cudbg_compress_hdr) >
            pdbg_buff->size)
                return CUDBG_STATUS_NO_MEM;

        pin_buff->data = (char *)pdbg_buff->data + pdbg_buff->offset;
        pin_buff->offset = 0;
        pin_buff->size = sizeof(struct cudbg_compress_hdr);
        pdbg_buff->offset += sizeof(struct cudbg_compress_hdr);
        return 0;
}

int cudbg_compress_buff(struct cudbg_init *pdbg_init,
                        struct cudbg_buffer *pin_buff,
                        struct cudbg_buffer *pout_buff)
{
        struct cudbg_buffer temp_buff = { 0 };
        struct z_stream_s compress_stream;
        struct cudbg_compress_hdr *c_hdr;
        int rc;

        /* Write compression header to output buffer before compression */
        rc = cudbg_get_compress_hdr(pout_buff, &temp_buff);
        if (rc)
                return rc;

        c_hdr = (struct cudbg_compress_hdr *)temp_buff.data;
        c_hdr->compress_id = CUDBG_ZLIB_COMPRESS_ID;

        memset(&compress_stream, 0, sizeof(struct z_stream_s));
        compress_stream.workspace = pdbg_init->workspace;
        rc = zlib_deflateInit2(&compress_stream, Z_DEFAULT_COMPRESSION,
                               Z_DEFLATED, CUDBG_ZLIB_WIN_BITS,
                               CUDBG_ZLIB_MEM_LVL, Z_DEFAULT_STRATEGY);
        if (rc != Z_OK)
                return CUDBG_SYSTEM_ERROR;

        compress_stream.next_in = pin_buff->data;
        compress_stream.avail_in = pin_buff->size;
        compress_stream.next_out = pout_buff->data + pout_buff->offset;
        compress_stream.avail_out = pout_buff->size - pout_buff->offset;

        rc = zlib_deflate(&compress_stream, Z_FINISH);
        if (rc != Z_STREAM_END)
                return CUDBG_SYSTEM_ERROR;

        rc = zlib_deflateEnd(&compress_stream);
        if (rc != Z_OK)
                return CUDBG_SYSTEM_ERROR;

        c_hdr->compress_size = compress_stream.total_out;
        c_hdr->decompress_size = pin_buff->size;
        pout_buff->offset += compress_stream.total_out;

        return 0;
}