/*

 * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.

 * All rights reserved.

 *

 * This source code is licensed under both the BSD-style license (found in the

 * LICENSE file in the root directory of this source tree) and the GPLv2 (found

 * in the COPYING file in the root directory of this source tree).

 */

#ifndef ZSTD_LDM_H

#define ZSTD_LDM_H

#if defined (__cplusplus)

extern "C" {

#endif

#include "zstd_compress_internal.h"   /* ldmParams_t, U32 */

#include "zstd.h"   /* ZSTD_CCtx, size_t */

/*-*************************************

*  Long distance matching

***************************************/

#define ZSTD_LDM_DEFAULT_WINDOW_LOG ZSTD_WINDOWLOG_LIMIT_DEFAULT

/**

 * ZSTD_ldm_generateSequences():

 *

 * Generates the sequences using the long distance match finder.

 * Generates long range matching sequences in `sequences`, which parse a prefix

 * of the source. `sequences` must be large enough to store every sequence,

 * which can be checked with `ZSTD_ldm_getMaxNbSeq()`.

 * @returns 0 or an error code.

 *

 * NOTE: The user must have called ZSTD_window_update() for all of the input

 * they have, even if they pass it to ZSTD_ldm_generateSequences() in chunks.

 * NOTE: This function returns an error if it runs out of space to store

 *       sequences.

 */

size_t ZSTD_ldm_generateSequences(

            ldmState_t* ldms, rawSeqStore_t* sequences,

            ldmParams_t const* params, void const* src, size_t srcSize);

/**

 * ZSTD_ldm_blockCompress():

 *

 * Compresses a block using the predefined sequences, along with a secondary

 * block compressor. The literals section of every sequence is passed to the

 * secondary block compressor, and those sequences are interspersed with the

 * predefined sequences. Returns the length of the last literals.

 * Updates `rawSeqStore.pos` to indicate how many sequences have been consumed.

 * `rawSeqStore.seq` may also be updated to split the last sequence between two

 * blocks.

 * @return The length of the last literals.

 *

 * NOTE: The source must be at most the maximum block size, but the predefined

 * sequences can be any size, and may be longer than the block. In the case that

 * they are longer than the block, the last sequences may need to be split into

 * two. We handle that case correctly, and update `rawSeqStore` appropriately.

 * NOTE: This function does not return any errors.

 */

size_t ZSTD_ldm_blockCompress(rawSeqStore_t* rawSeqStore,

            ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],

            void const* src, size_t srcSize);

/**

 * ZSTD_ldm_skipSequences():

 *

 * Skip past `srcSize` bytes worth of sequences in `rawSeqStore`.

 * Avoids emitting matches less than `minMatch` bytes.

 * Must be called for data with is not passed to ZSTD_ldm_blockCompress().

 */

void ZSTD_ldm_skipSequences(rawSeqStore_t* rawSeqStore, size_t srcSize,

    U32 const minMatch);

/** ZSTD_ldm_getTableSize() :

 *  Estimate the space needed for long distance matching tables or 0 if LDM is

 *  disabled.

 */

size_t ZSTD_ldm_getTableSize(ldmParams_t params);

/** ZSTD_ldm_getSeqSpace() :

 *  Return an upper bound on the number of sequences that can be produced by

 *  the long distance matcher, or 0 if LDM is disabled.

 */

size_t ZSTD_ldm_getMaxNbSeq(ldmParams_t params, size_t maxChunkSize);

/** ZSTD_ldm_adjustParameters() :

 *  If the params->hashRateLog is not set, set it to its default value based on

 *  windowLog and params->hashLog.

 *

 *  Ensures that params->bucketSizeLog is <= params->hashLog (setting it to

 *  params->hashLog if it is not).

 *

 *  Ensures that the minMatchLength >= targetLength during optimal parsing.

 */

void ZSTD_ldm_adjustParameters(ldmParams_t* params,

                               ZSTD_compressionParameters const* cParams);

#if defined (__cplusplus)

}

#endif

#endif /* ZSTD_FAST_H */