/*

 * The deflate_quick deflate strategy, designed to be used when cycles are

 * at a premium.

 *

 * Copyright (C) 2013 Intel Corporation. All rights reserved.

 * Authors:

 *  Wajdi Feghali   <wajdi.k.feghali@intel.com>

 *  Jim Guilford    <james.guilford@intel.com>

 *  Vinodh Gopal    <vinodh.gopal@intel.com>

 *     Erdinc Ozturk   <erdinc.ozturk@intel.com>

 *  Jim Kukunas     <james.t.kukunas@linux.intel.com>

 *

 * Portions are Copyright (C) 2016 12Sided Technology, LLC.

 * Author:

 *  Phil Vachon     <pvachon@12sidedtech.com>

 *

 * For conditions of distribution and use, see copyright notice in zlib.h

 */

#include "zbuild.h"

#include "deflate.h"

#include "deflate_p.h"

#include "functable.h"

#include "trees_emit.h"

extern const ct_data static_ltree[L_CODES+2];

extern const ct_data static_dtree[D_CODES];

#define QUICK_START_BLOCK(s, last) { \

    zng_tr_emit_tree(s, STATIC_TREES, last); \

    s->block_open = 1 + (int)last; \

    s->block_start = (int)s->strstart; \

}

#define QUICK_END_BLOCK(s, last) { \

    if (s->block_open) { \

        zng_tr_emit_end_block(s, static_ltree, last); \

        s->block_open = 0; \

        s->block_start = (int)s->strstart; \

        flush_pending(s->strm); \

        if (s->strm->avail_out == 0) \

            return (last) ? finish_started : need_more; \

    } \

}

Z_INTERNAL block_state deflate_quick(deflate_state *s, int flush) {

    Pos hash_head;

    int64_t dist;

    unsigned match_len, last;

    last = (flush == Z_FINISH) ? 1 : 0;

    if (UNLIKELY(last && s->block_open != 2)) {

        /* Emit end of previous block */

        QUICK_END_BLOCK(s, 0);

        /* Emit start of last block */

        QUICK_START_BLOCK(s, last);

    } else if (UNLIKELY(s->block_open == 0 && s->lookahead > 0)) {

        /* Start new block only when we have lookahead data, so that if no

           input data is given an empty block will not be written */

        QUICK_START_BLOCK(s, last);

    }

    for (;;) {

        if (UNLIKELY(s->pending + ((BIT_BUF_SIZE + 7) >> 3) >= s->pending_buf_size)) {

            flush_pending(s->strm);

            if (s->strm->avail_out == 0) {

                return (last && s->strm->avail_in == 0 && s->bi_valid == 0 && s->block_open == 0) ? finish_started : need_more;

            }

        }

        if (UNLIKELY(s->lookahead < MIN_LOOKAHEAD)) {

            fill_window(s);

            if (UNLIKELY(s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH)) {

                return need_more;

            }

            if (UNLIKELY(s->lookahead == 0))

                break;

            if (UNLIKELY(s->block_open == 0)) {

                /* Start new block when we have lookahead data, so that if no

                   input data is given an empty block will not be written */

                QUICK_START_BLOCK(s, last);

            }

        }

        if (LIKELY(s->lookahead >= MIN_MATCH)) {

            hash_head = functable.quick_insert_string(s, s->strstart);

            dist = (int64_t)s->strstart - hash_head;

            if (dist <= MAX_DIST(s) && dist > 0) {

                match_len = functable.compare258(s->window + s->strstart, s->window + hash_head);

                if (match_len >= MIN_MATCH) {

                    if (UNLIKELY(match_len > s->lookahead))

                        match_len = s->lookahead;

                    check_match(s, s->strstart, hash_head, match_len);

                    zng_tr_emit_dist(s, static_ltree, static_dtree, match_len - MIN_MATCH, (uint32_t)dist);

                    s->lookahead -= match_len;

                    s->strstart += match_len;

                    continue;

                }

            }

        }

        zng_tr_emit_lit(s, static_ltree, s->window[s->strstart]);

        s->strstart++;

        s->lookahead--;

    }

    s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1;

    if (UNLIKELY(last)) {

        QUICK_END_BLOCK(s, 1);

        return finish_done;

    }

    QUICK_END_BLOCK(s, 0);

    return block_done;

}