/* deflate_huff.c -- compress data using huffman encoding only strategy

 *

 * Copyright (C) 1995-2024 Jean-loup Gailly and Mark Adler

 * 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"

/* ===========================================================================

 * For Z_HUFFMAN_ONLY, do not look for matches.  Do not maintain a hash table.

 * (It will be regenerated if this run of deflate switches away from Huffman.)

 */

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

    unsigned char *window = s->window;

    int bflush = 0;         /* set if current block must be flushed */

    unsigned int lookahead = s->lookahead;

    unsigned int strstart = s->strstart;

    for (;;) {

        /* Make sure that we have a literal to write. */

        if (UNLIKELY(lookahead == 0)) {

            s->lookahead = lookahead;

            s->strstart = strstart;

            PREFIX(fill_window)(s);

            lookahead = s->lookahead;

            strstart = s->strstart;

            if (UNLIKELY(lookahead == 0)) {

                if (flush == Z_NO_FLUSH)

                    return need_more;

                break;      /* flush the current block */

            }

        }

        /* Output a literal byte */

        bflush = zng_tr_tally_lit(s, window[strstart]);

        lookahead--;

        strstart++;

        if (bflush) {

            s->lookahead = lookahead;

            s->strstart = strstart;

            FLUSH_BLOCK(s, window, 0);

        }

    }

    s->lookahead = lookahead;

    s->strstart = strstart;

    s->insert = 0;

    if (flush == Z_FINISH) {

        FLUSH_BLOCK(s, window, 1);

        return finish_done;

    }

    if (s->sym_next)

        FLUSH_BLOCK(s, window, 0);

    return block_done;

}