Commit 9a549338 authored by Mikhail Zaslonko's avatar Mikhail Zaslonko Committed by Andrew Morton
Browse files

lib/zlib: implement switching between DFLTCC and software 

This commit is based on:
  https://github.com/zlib-ng/zlib-ng/commit/fc04275

Link: https://lkml.kernel.org/r/20230126131428.1222214-3-zaslonko@linux.ibm.com


Signed-off-by: default avatarMikhail Zaslonko <zaslonko@linux.ibm.com>
Acked-by: default avatarIlya Leoshkevich <iii@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 4cc06c9a

lib/zlib_dfltcc/dfltcc_deflate.c

+22 −16
Original line number Diff line number Diff line
@@ -112,30 +112,36 @@ int dfltcc_deflate( 
    int soft_bcc;

    int no_flush;



    if (!dfltcc_can_deflate(strm))

    if (!dfltcc_can_deflate(strm)) {

        /* Clear history. */

        if (flush == Z_FULL_FLUSH)

            param->hl = 0;

        return 0;

    }



again:

    masked_avail_in = 0;

    soft_bcc = 0;

    no_flush = flush == Z_NO_FLUSH;



    /* Trailing empty block. Switch to software, except when Continuation Flag

     * is set, which means that DFLTCC has buffered some output in the

     * parameter block and needs to be called again in order to flush it.

    /* No input data. Return, except when Continuation Flag is set, which means

     * that DFLTCC has buffered some output in the parameter block and needs to

     * be called again in order to flush it.

     */

    if (flush == Z_FINISH && strm->avail_in == 0 && !param->cf) {

        if (param->bcf) {

    if (strm->avail_in == 0 && !param->cf) {

        /* A block is still open, and the hardware does not support closing

         * blocks without adding data. Thus, close it manually.

         */

        if (!no_flush && param->bcf) {

            send_eobs(strm, param);

            param->bcf = 0;

        }

        /* Let one of deflate_* functions write a trailing empty block. */

        if (flush == Z_FINISH)

            return 0;

    }



    if (strm->avail_in == 0 && !param->cf) {

        /* Clear history. */

        if (flush == Z_FULL_FLUSH)

            param->hl = 0;

        *result = need_more;

        return 1;

    }
@@ -189,7 +195,7 @@ int dfltcc_deflate( 
    param->cvt = CVT_ADLER32;

    if (!no_flush)

        /* We need to close a block. Always do this in software - when there is

         * no input data, the hardware will not nohor BCC. */

         * no input data, the hardware will not hohor BCC. */

        soft_bcc = 1;

    if (flush == Z_FINISH && !param->bcf)

        /* We are about to open a BFINAL block, set Block Header Final bit
@@ -204,8 +210,8 @@ int dfltcc_deflate( 
    param->sbb = (unsigned int)state->bi_valid;

    if (param->sbb > 0)

        *strm->next_out = (Byte)state->bi_buf;

    if (param->hl)

        param->nt = 0; /* Honor history */

    /* Honor history and check value */

    param->nt = 0;

    param->cv = strm->adler;



    /* When opening a block, choose a Huffman-Table Type */