/* Copyright (c) 2014, Matt Stancliff <matt@genges.com>
 * Copyright (c) 2020, Amazon Web Services
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   * Redistributions of source code must retain the above copyright 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.
 *   * Neither the name of Redis nor the names of its contributors may be used
 *     to endorse or promote products derived from this software without
 *     specific prior written permission.
 *
 * 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. */

#include <stdlib.h>
#include "crc64.h"
#include "crcspeed.h"
#include "redisassert.h"
#include "testhelp.h"
static uint64_t crc64_table[8][256] = {{0}};

#define POLY UINT64_C(0xad93d23594c935a9)
/******************** BEGIN GENERATED PYCRC FUNCTIONS ********************/
/**
 * Generated on Sun Dec 21 14:14:07 2014,
 * by pycrc v0.8.2, https://www.tty1.net/pycrc/
 *
 * LICENSE ON GENERATED CODE:
 * ==========================
 * As of version 0.6, pycrc is released under the terms of the MIT licence.
 * The code generated by pycrc is not considered a substantial portion of the
 * software, therefore the author of pycrc will not claim any copyright on
 * the generated code.
 * ==========================
 *
 * CRC configuration:
 *    Width        = 64
 *    Poly         = 0xad93d23594c935a9
 *    XorIn        = 0xffffffffffffffff
 *    ReflectIn    = True
 *    XorOut       = 0x0000000000000000
 *    ReflectOut   = True
 *    Algorithm    = bit-by-bit-fast
 *
 * Modifications after generation (by matt):
 *   - included finalize step in-line with update for single-call generation
 *   - re-worked some inner variable architectures
 *   - adjusted function parameters to match expected prototypes.
 *****************************************************************************/

/**
 * Reflect all bits of a \a data word of \a data_len bytes.
 *
 * \param data         The data word to be reflected.
 * \param data_len     The width of \a data expressed in number of bits.
 * \return             The reflected data.
 *****************************************************************************/
static inline uint_fast64_t crc_reflect(uint_fast64_t data, size_t data_len) {
    /* only ever called for data_len == 64 in this codebase
     *
     * Borrowed from bit twiddling hacks, original in the public domain.
     * https://graphics.stanford.edu/~seander/bithacks.html#ReverseParallel
     * Extended to 64 bits, and added byteswap for final 3 steps.
     * 16-30x 64-bit operations, no comparisons (16 for native byteswap, 30 for pure C)
     */

    assert(data_len <= 64);
    /* swap odd and even bits */
    data = ((data >> 1) & 0x5555555555555555ULL) | ((data & 0x5555555555555555ULL) << 1);
    /* swap consecutive pairs */
    data = ((data >> 2) & 0x3333333333333333ULL) | ((data & 0x3333333333333333ULL) << 2);
    /* swap nibbles ... */
    data = ((data >> 4) & 0x0F0F0F0F0F0F0F0FULL) | ((data & 0x0F0F0F0F0F0F0F0FULL) << 4);
#if defined(__GNUC__) || defined(__clang__)
    data = __builtin_bswap64(data);
#else
    /* swap bytes */
    data = ((data >> 8) & 0x00FF00FF00FF00FFULL) | ((data & 0x00FF00FF00FF00FFULL) << 8);
    /* swap 2-byte long pairs */
    data = ( data >> 16 &     0xFFFF0000FFFFULL) | ((data &     0xFFFF0000FFFFULL) << 16);
    /* swap 4-byte quads */
    data = ( data >> 32 &         0xFFFFFFFFULL) | ((data &         0xFFFFFFFFULL) << 32);
#endif
    /* adjust for non-64-bit reversals */
    return data >> (64 - data_len);
}

/**
 *  Update the crc value with new data.
 *
 * \param crc      The current crc value.
 * \param data     Pointer to a buffer of \a data_len bytes.
 * \param data_len Number of bytes in the \a data buffer.
 * \return         The updated crc value.
 ******************************************************************************/
uint64_t _crc64(uint_fast64_t crc, const void *in_data, const uint64_t len) {
    const uint8_t *data = in_data;
    unsigned long long bit;

    for (uint64_t offset = 0; offset < len; offset++) {
        uint8_t c = data[offset];
        for (uint_fast8_t i = 0x01; i & 0xff; i <<= 1) {
            bit = crc & 0x8000000000000000;
            if (c & i) {
                bit = !bit;
            }

            crc <<= 1;
            if (bit) {
                crc ^= POLY;
            }
        }

        crc &= 0xffffffffffffffff;
    }

    crc = crc & 0xffffffffffffffff;
    return crc_reflect(crc, 64) ^ 0x0000000000000000;
}

/******************** END GENERATED PYCRC FUNCTIONS ********************/

/* Initializes the 16KB lookup tables. */
void crc64_init(void) {
    crcspeed64native_init(_crc64, crc64_table);
}

/* Compute crc64 */
uint64_t crc64(uint64_t crc, const unsigned char *s, uint64_t l) {
    return crcspeed64native(crc64_table, crc, (void *) s, l);
}

/* Test main */
#ifdef REDIS_TEST
#include <stdio.h>

static void genBenchmarkRandomData(char *data, int count);
static int bench_crc64(unsigned char *data, uint64_t size, long long passes, uint64_t check, char *name, int csv);
static void bench_combine(char *label, uint64_t size, uint64_t expect, int csv);
long long _ustime(void);

#include <inttypes.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>
#include <sys/time.h>
#include <unistd.h>

#include "zmalloc.h"
#include "crccombine.h"

long long _ustime(void) {
    struct timeval tv;
    long long ust;

    gettimeofday(&tv, NULL);
    ust = ((long long)tv.tv_sec)*1000000;
    ust += tv.tv_usec;
    return ust;
}

static int bench_crc64(unsigned char *data, uint64_t size, long long passes, uint64_t check, char *name, int csv) {
    uint64_t min = size, hash;
    long long original_start = _ustime(), original_end;
    for (long long i=passes; i > 0; i--) {
        hash = crc64(0, data, size);
    }
    original_end = _ustime();
    min = (original_end - original_start) * 1000 / passes;
    /* approximate nanoseconds without nstime */
    if (csv) {
        printf("%s,%" PRIu64 ",%" PRIu64 ",%d\n",
               name, size, (1000 * size) / min, hash == check);
    } else {
        printf("test size=%" PRIu64 " algorithm=%s %" PRIu64 " M/sec matches=%d\n",
               size, name, (1000 * size) / min, hash == check);
    }
    return hash != check;
}

const uint64_t BENCH_RPOLY = UINT64_C(0x95ac9329ac4bc9b5);

static void bench_combine(char *label, uint64_t size, uint64_t expect, int csv) {
    uint64_t min = size, start = expect, thash = expect ^ (expect >> 17);
    long long original_start = _ustime(), original_end;
    for (int i=0; i < 1000; i++) {
        crc64_combine(thash, start, size, BENCH_RPOLY, 64);
    }
    original_end = _ustime();
    /* ran 1000 times, want ns per, counted us per 1000 ... */
    min = original_end - original_start;
    if (csv) {
        printf("%s,%" PRIu64 ",%" PRIu64 "\n", label, size, min);
    } else {
        printf("%s size=%" PRIu64 " in %" PRIu64 " nsec\n", label, size, min);
    }
}

static void genBenchmarkRandomData(char *data, int count) {
    static uint32_t state = 1234;
    int i = 0;

    while (count--) {
        state = (state*1103515245+12345);
        data[i++] = '0'+((state>>16)&63);
    }
}

#define UNUSED(x) (void)(x)
int crc64Test(int argc, char *argv[], int flags) {

    uint64_t crc64_test_size = 0;
    int i, lastarg, csv = 0, loop = 0, combine = 0, testAll = 0;
    
again:
    if ((argc>=4) && (!strcmp(argv[3],"custom"))) {        
        for (i = 4; i < argc; i++) {
            lastarg = (i == (argc - 1));
            if (!strcmp(argv[i], "--help")) {
                goto usage;
            } else if (!strcmp(argv[i], "--csv")) {
                csv = 1;
            } else if (!strcmp(argv[i], "-l")) {
                loop = 1;
            } else if (!strcmp(argv[i], "--crc")) {
                if (lastarg) goto invalid;
                crc64_test_size = atoll(argv[++i]);
            } else if (!strcmp(argv[i], "--combine")) {
                combine = 1;
            } else {
                invalid:
                printf("Invalid option \"%s\" or option argument missing\n\n",
                       argv[i]);
                usage:
                printf(
                        "Usage: crc64 [OPTIONS]\n\n"
                        " --csv              Output in CSV format\n"
                        " -l                 Loop. Run the tests forever\n"
                        " --crc <bytes>      Benchmark crc64 faster options, using a buffer this big, and quit when done.\n"
                        " --combine          Benchmark crc64 combine value ranges and timings.\n"
                );
                return 1;
            }
        }
    } else {
        crc64_test_size = 50000; 
        testAll = 1;
        if (flags & REDIS_TEST_ACCURATE) crc64_test_size = 5000000;
    }
    
    if ((crc64_test_size == 0 && combine == 0) || testAll) {
        crc64_init();
        printf("[calcula]: e9c6d914c4b8d9ca == %016" PRIx64 "\n",
            (uint64_t)_crc64(0, "123456789", 9));
        printf("[64speed]: e9c6d914c4b8d9ca == %016" PRIx64 "\n",
            (uint64_t)crc64(0, (unsigned char*)"123456789", 9));
        char li[] = "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed "
                    "do eiusmod tempor incididunt ut labore et dolore magna "
                    "aliqua. Ut enim ad minim veniam, quis nostrud exercitation "
                    "ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis "
                    "aute irure dolor in reprehenderit in voluptate velit esse "
                    "cillum dolore eu fugiat nulla pariatur. Excepteur sint "
                    "occaecat cupidatat non proident, sunt in culpa qui officia "
                    "deserunt mollit anim id est laborum.";
        printf("[calcula]: c7794709e69683b3 == %016" PRIx64 "\n",
            (uint64_t)_crc64(0, li, sizeof(li)));
        printf("[64speed]: c7794709e69683b3 == %016" PRIx64 "\n",
            (uint64_t)crc64(0, (unsigned char*)li, sizeof(li)));
        
        if (!testAll) return 0;
    }

    int init_this_loop = 1;
    long long init_start, init_end;

    do {
        unsigned char* data = NULL;
        uint64_t passes = 0;
        if (crc64_test_size) {
            data = zmalloc(crc64_test_size);
            genBenchmarkRandomData((char*)data, crc64_test_size);
            /* We want to hash about 1 gig of data in total, looped, to get a good
             * idea of our performance.
             */
            passes = (UINT64_C(0x100000000) / crc64_test_size);
            passes = passes >= 2 ? passes : 2;
            passes = passes <= 1000 ? passes : 1000;
        }

        crc64_init();
        /* warm up the cache */
        set_crc64_cutoffs(crc64_test_size+1, crc64_test_size+1);
        uint64_t expect = crc64(0, data, crc64_test_size);

        if ((!combine || testAll) && crc64_test_size) {
            if (csv && init_this_loop) printf("algorithm,buffer,performance,crc64_matches\n");

            /* get the single-character version for single-byte Redis behavior */
            set_crc64_cutoffs(0, crc64_test_size+1);
            assert(!bench_crc64(data, crc64_test_size, passes, expect, "crc_1byte", csv));

            set_crc64_cutoffs(crc64_test_size+1, crc64_test_size+1);
            /* run with 8-byte "single" path, crcfaster */
            assert(!(bench_crc64(data, crc64_test_size, passes, expect, "crcspeed", csv)));

            /* run with dual 8-byte paths */
            set_crc64_cutoffs(1, crc64_test_size+1);
            assert(!(bench_crc64(data, crc64_test_size, passes, expect, "crcdual", csv)));

            /* run with tri 8-byte paths */
            set_crc64_cutoffs(1, 1);
            assert(!(bench_crc64(data, crc64_test_size, passes, expect, "crctri", csv)));

            /* Be free memory region, be free. */
            zfree(data);
            data = NULL;
        }

        uint64_t INIT_SIZE = UINT64_C(0xffffffffffffffff);
        if (combine || testAll) {
            if (init_this_loop) {
                init_start = _ustime();
                crc64_combine(
                    UINT64_C(0xdeadbeefdeadbeef),
                    UINT64_C(0xfeebdaedfeebdaed),
                    INIT_SIZE,
                    BENCH_RPOLY, 64);
                init_end = _ustime();

                init_end -= init_start;
                init_end *= 1000;
                if (csv) {
                    printf("operation,size,nanoseconds\n");
                    printf("init_64,%" PRIu64 ",%" PRIu64 "\n", INIT_SIZE, (uint64_t)init_end);
                } else {
                    printf("init_64 size=%" PRIu64 " in %" PRIu64 " nsec\n", INIT_SIZE, (uint64_t)init_end);
                }
                /* use the hash itself as the size (unpredictable) */
                bench_combine("hash_as_size_combine", crc64_test_size, expect, csv);

                /* let's do something big (predictable, so fast) */
                bench_combine("largest_combine", INIT_SIZE, expect, csv);
            }
            bench_combine("combine", crc64_test_size, expect, csv);
        }
        init_this_loop = 0;
        /* step down by ~1.641 for a range of test sizes */
        crc64_test_size -= (crc64_test_size >> 2) + (crc64_test_size >> 3) + (crc64_test_size >> 6);
    } while (crc64_test_size > 3);
    if (loop) goto again;
    return 0;
}

#endif
