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    notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above
    copyright notice, this list of conditions and the following disclaimer
    in the documentation and/or other materials provided with the
    distribution.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    You can contact the author at :
       - LZ4 source repository : https://github.com/lz4/lz4
       - LZ4 public forum : https://groups.google.com/forum/#!forum/lz4c
*/
/* note : lz4hc is not an independent module, it requires lz4.h/lz4.c for proper compilation */


/* *************************************
*  Tuning Parameter
***************************************/

/*! HEAPMODE :
 *  Select how default compression function will allocate workplace memory,
 *  in stack (0:fastest), or in heap (1:requires malloc()).
 *  Since workplace is rather large, heap mode is recommended.
 */
#ifndef LZ4HC_HEAPMODE
#  define LZ4HC_HEAPMODE 1
#endif


/*===    Dependency    ===*/
#define LZ4_HC_STATIC_LINKING_ONLY
#include "lz4hc.h"


/*===   Common LZ4 definitions   ===*/
#if defined(__GNUC__)
#  pragma GCC diagnostic ignored "-Wunused-function"
#endif
#if defined (__clang__)
#  pragma clang diagnostic ignored "-Wunused-function"
#endif

#define LZ4_COMMONDEFS_ONLY
#include "lz4.c"   /* LZ4_count, constants, mem */


/*===   Constants   ===*/
#define OPTIMAL_ML (int)((ML_MASK-1)+MINMATCH)


/*===   Macros   ===*/
#define MIN(a,b)   ( (a) < (b) ? (a) : (b) )
#define MAX(a,b)   ( (a) > (b) ? (a) : (b) )
#define HASH_FUNCTION(i)         (((i) * 2654435761U) >> ((MINMATCH*8)-LZ4HC_HASH_LOG))
#define DELTANEXTMAXD(p)         chainTable[(p) & LZ4HC_MAXD_MASK]    /* flexible, LZ4HC_MAXD dependent */
#define DELTANEXTU16(table, pos) table[(U16)(pos)]   /* faster */

static U32 LZ4HC_hashPtr(const void* ptr) { return HASH_FUNCTION(LZ4_read32(ptr)); }



/**************************************
*  HC Compression
**************************************/
static void LZ4HC_init (LZ4HC_CCtx_internal* hc4, const BYTE* start)
{
    MEM_INIT((void*)hc4->hashTable, 0, sizeof(hc4->hashTable));
    MEM_INIT(hc4->chainTable, 0xFF, sizeof(hc4->chainTable));
    hc4->nextToUpdate = 64 KB;
    hc4->base = start - 64 KB;
    hc4->end = start;
    hc4->dictBase = start - 64 KB;
    hc4->dictLimit = 64 KB;
    hc4->lowLimit = 64 KB;
}


/* Update chains up to ip (excluded) */
LZ4_FORCE_INLINE void LZ4HC_Insert (LZ4HC_CCtx_internal* hc4, const BYTE* ip)
{
    U16* const chainTable = hc4->chainTable;
    U32* const hashTable  = hc4->hashTable;
    const BYTE* const base = hc4->base;
    U32 const target = (U32)(ip - base);
    U32 idx = hc4->nextToUpdate;

    while (idx < target) {
        U32 const h = LZ4HC_hashPtr(base+idx);
        size_t delta = idx - hashTable[h];
        if (delta>MAX_DISTANCE) delta = MAX_DISTANCE;
        DELTANEXTU16(chainTable, idx) = (U16)delta;
        hashTable[h] = idx;
        idx++;
    }

    hc4->nextToUpdate = target;
}

/** LZ4HC_countBack() :
 * @return : negative value, nb of common bytes before ip/match */
LZ4_FORCE_INLINE
int LZ4HC_countBack(const BYTE* const ip, const BYTE* const match,
                    const BYTE* const iMin, const BYTE* const mMin)
{
    int back=0;
    while ( (ip+back > iMin)
         && (match+back > mMin)
         && (ip[back-1] == match[back-1]))
            back--;
    return back;
}