linux/lib/xxhash.c
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   1/*
   2 * xxHash - Extremely Fast Hash algorithm
   3 * Copyright (C) 2012-2016, Yann Collet.
   4 *
   5 * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
   6 *
   7 * Redistribution and use in source and binary forms, with or without
   8 * modification, are permitted provided that the following conditions are
   9 * met:
  10 *
  11 *   * Redistributions of source code must retain the above copyright
  12 *     notice, this list of conditions and the following disclaimer.
  13 *   * Redistributions in binary form must reproduce the above
  14 *     copyright notice, this list of conditions and the following disclaimer
  15 *     in the documentation and/or other materials provided with the
  16 *     distribution.
  17 *
  18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29 *
  30 * This program is free software; you can redistribute it and/or modify it under
  31 * the terms of the GNU General Public License version 2 as published by the
  32 * Free Software Foundation. This program is dual-licensed; you may select
  33 * either version 2 of the GNU General Public License ("GPL") or BSD license
  34 * ("BSD").
  35 *
  36 * You can contact the author at:
  37 * - xxHash homepage: http://cyan4973.github.io/xxHash/
  38 * - xxHash source repository: https://github.com/Cyan4973/xxHash
  39 */
  40
  41#include <asm/unaligned.h>
  42#include <linux/errno.h>
  43#include <linux/compiler.h>
  44#include <linux/kernel.h>
  45#include <linux/module.h>
  46#include <linux/string.h>
  47#include <linux/xxhash.h>
  48
  49/*-*************************************
  50 * Macros
  51 **************************************/
  52#define xxh_rotl32(x, r) ((x << r) | (x >> (32 - r)))
  53#define xxh_rotl64(x, r) ((x << r) | (x >> (64 - r)))
  54
  55#ifdef __LITTLE_ENDIAN
  56# define XXH_CPU_LITTLE_ENDIAN 1
  57#else
  58# define XXH_CPU_LITTLE_ENDIAN 0
  59#endif
  60
  61/*-*************************************
  62 * Constants
  63 **************************************/
  64static const uint32_t PRIME32_1 = 2654435761U;
  65static const uint32_t PRIME32_2 = 2246822519U;
  66static const uint32_t PRIME32_3 = 3266489917U;
  67static const uint32_t PRIME32_4 =  668265263U;
  68static const uint32_t PRIME32_5 =  374761393U;
  69
  70static const uint64_t PRIME64_1 = 11400714785074694791ULL;
  71static const uint64_t PRIME64_2 = 14029467366897019727ULL;
  72static const uint64_t PRIME64_3 =  1609587929392839161ULL;
  73static const uint64_t PRIME64_4 =  9650029242287828579ULL;
  74static const uint64_t PRIME64_5 =  2870177450012600261ULL;
  75
  76/*-**************************
  77 *  Utils
  78 ***************************/
  79void xxh32_copy_state(struct xxh32_state *dst, const struct xxh32_state *src)
  80{
  81        memcpy(dst, src, sizeof(*dst));
  82}
  83EXPORT_SYMBOL(xxh32_copy_state);
  84
  85void xxh64_copy_state(struct xxh64_state *dst, const struct xxh64_state *src)
  86{
  87        memcpy(dst, src, sizeof(*dst));
  88}
  89EXPORT_SYMBOL(xxh64_copy_state);
  90
  91/*-***************************
  92 * Simple Hash Functions
  93 ****************************/
  94static uint32_t xxh32_round(uint32_t seed, const uint32_t input)
  95{
  96        seed += input * PRIME32_2;
  97        seed = xxh_rotl32(seed, 13);
  98        seed *= PRIME32_1;
  99        return seed;
 100}
 101
 102uint32_t xxh32(const void *input, const size_t len, const uint32_t seed)
 103{
 104        const uint8_t *p = (const uint8_t *)input;
 105        const uint8_t *b_end = p + len;
 106        uint32_t h32;
 107
 108        if (len >= 16) {
 109                const uint8_t *const limit = b_end - 16;
 110                uint32_t v1 = seed + PRIME32_1 + PRIME32_2;
 111                uint32_t v2 = seed + PRIME32_2;
 112                uint32_t v3 = seed + 0;
 113                uint32_t v4 = seed - PRIME32_1;
 114
 115                do {
 116                        v1 = xxh32_round(v1, get_unaligned_le32(p));
 117                        p += 4;
 118                        v2 = xxh32_round(v2, get_unaligned_le32(p));
 119                        p += 4;
 120                        v3 = xxh32_round(v3, get_unaligned_le32(p));
 121                        p += 4;
 122                        v4 = xxh32_round(v4, get_unaligned_le32(p));
 123                        p += 4;
 124                } while (p <= limit);
 125
 126                h32 = xxh_rotl32(v1, 1) + xxh_rotl32(v2, 7) +
 127                        xxh_rotl32(v3, 12) + xxh_rotl32(v4, 18);
 128        } else {
 129                h32 = seed + PRIME32_5;
 130        }
 131
 132        h32 += (uint32_t)len;
 133
 134        while (p + 4 <= b_end) {
 135                h32 += get_unaligned_le32(p) * PRIME32_3;
 136                h32 = xxh_rotl32(h32, 17) * PRIME32_4;
 137                p += 4;
 138        }
 139
 140        while (p < b_end) {
 141                h32 += (*p) * PRIME32_5;
 142                h32 = xxh_rotl32(h32, 11) * PRIME32_1;
 143                p++;
 144        }
 145
 146        h32 ^= h32 >> 15;
 147        h32 *= PRIME32_2;
 148        h32 ^= h32 >> 13;
 149        h32 *= PRIME32_3;
 150        h32 ^= h32 >> 16;
 151
 152        return h32;
 153}
 154EXPORT_SYMBOL(xxh32);
 155
 156static uint64_t xxh64_round(uint64_t acc, const uint64_t input)
 157{
 158        acc += input * PRIME64_2;
 159        acc = xxh_rotl64(acc, 31);
 160        acc *= PRIME64_1;
 161        return acc;
 162}
 163
 164static uint64_t xxh64_merge_round(uint64_t acc, uint64_t val)
 165{
 166        val = xxh64_round(0, val);
 167        acc ^= val;
 168        acc = acc * PRIME64_1 + PRIME64_4;
 169        return acc;
 170}
 171
 172uint64_t xxh64(const void *input, const size_t len, const uint64_t seed)
 173{
 174        const uint8_t *p = (const uint8_t *)input;
 175        const uint8_t *const b_end = p + len;
 176        uint64_t h64;
 177
 178        if (len >= 32) {
 179                const uint8_t *const limit = b_end - 32;
 180                uint64_t v1 = seed + PRIME64_1 + PRIME64_2;
 181                uint64_t v2 = seed + PRIME64_2;
 182                uint64_t v3 = seed + 0;
 183                uint64_t v4 = seed - PRIME64_1;
 184
 185                do {
 186                        v1 = xxh64_round(v1, get_unaligned_le64(p));
 187                        p += 8;
 188                        v2 = xxh64_round(v2, get_unaligned_le64(p));
 189                        p += 8;
 190                        v3 = xxh64_round(v3, get_unaligned_le64(p));
 191                        p += 8;
 192                        v4 = xxh64_round(v4, get_unaligned_le64(p));
 193                        p += 8;
 194                } while (p <= limit);
 195
 196                h64 = xxh_rotl64(v1, 1) + xxh_rotl64(v2, 7) +
 197                        xxh_rotl64(v3, 12) + xxh_rotl64(v4, 18);
 198                h64 = xxh64_merge_round(h64, v1);
 199                h64 = xxh64_merge_round(h64, v2);
 200                h64 = xxh64_merge_round(h64, v3);
 201                h64 = xxh64_merge_round(h64, v4);
 202
 203        } else {
 204                h64  = seed + PRIME64_5;
 205        }
 206
 207        h64 += (uint64_t)len;
 208
 209        while (p + 8 <= b_end) {
 210                const uint64_t k1 = xxh64_round(0, get_unaligned_le64(p));
 211
 212                h64 ^= k1;
 213                h64 = xxh_rotl64(h64, 27) * PRIME64_1 + PRIME64_4;
 214                p += 8;
 215        }
 216
 217        if (p + 4 <= b_end) {
 218                h64 ^= (uint64_t)(get_unaligned_le32(p)) * PRIME64_1;
 219                h64 = xxh_rotl64(h64, 23) * PRIME64_2 + PRIME64_3;
 220                p += 4;
 221        }
 222
 223        while (p < b_end) {
 224                h64 ^= (*p) * PRIME64_5;
 225                h64 = xxh_rotl64(h64, 11) * PRIME64_1;
 226                p++;
 227        }
 228
 229        h64 ^= h64 >> 33;
 230        h64 *= PRIME64_2;
 231        h64 ^= h64 >> 29;
 232        h64 *= PRIME64_3;
 233        h64 ^= h64 >> 32;
 234
 235        return h64;
 236}
 237EXPORT_SYMBOL(xxh64);
 238
 239/*-**************************************************
 240 * Advanced Hash Functions
 241 ***************************************************/
 242void xxh32_reset(struct xxh32_state *statePtr, const uint32_t seed)
 243{
 244        /* use a local state for memcpy() to avoid strict-aliasing warnings */
 245        struct xxh32_state state;
 246
 247        memset(&state, 0, sizeof(state));
 248        state.v1 = seed + PRIME32_1 + PRIME32_2;
 249        state.v2 = seed + PRIME32_2;
 250        state.v3 = seed + 0;
 251        state.v4 = seed - PRIME32_1;
 252        memcpy(statePtr, &state, sizeof(state));
 253}
 254EXPORT_SYMBOL(xxh32_reset);
 255
 256void xxh64_reset(struct xxh64_state *statePtr, const uint64_t seed)
 257{
 258        /* use a local state for memcpy() to avoid strict-aliasing warnings */
 259        struct xxh64_state state;
 260
 261        memset(&state, 0, sizeof(state));
 262        state.v1 = seed + PRIME64_1 + PRIME64_2;
 263        state.v2 = seed + PRIME64_2;
 264        state.v3 = seed + 0;
 265        state.v4 = seed - PRIME64_1;
 266        memcpy(statePtr, &state, sizeof(state));
 267}
 268EXPORT_SYMBOL(xxh64_reset);
 269
 270int xxh32_update(struct xxh32_state *state, const void *input, const size_t len)
 271{
 272        const uint8_t *p = (const uint8_t *)input;
 273        const uint8_t *const b_end = p + len;
 274
 275        if (input == NULL)
 276                return -EINVAL;
 277
 278        state->total_len_32 += (uint32_t)len;
 279        state->large_len |= (len >= 16) | (state->total_len_32 >= 16);
 280
 281        if (state->memsize + len < 16) { /* fill in tmp buffer */
 282                memcpy((uint8_t *)(state->mem32) + state->memsize, input, len);
 283                state->memsize += (uint32_t)len;
 284                return 0;
 285        }
 286
 287        if (state->memsize) { /* some data left from previous update */
 288                const uint32_t *p32 = state->mem32;
 289
 290                memcpy((uint8_t *)(state->mem32) + state->memsize, input,
 291                        16 - state->memsize);
 292
 293                state->v1 = xxh32_round(state->v1, get_unaligned_le32(p32));
 294                p32++;
 295                state->v2 = xxh32_round(state->v2, get_unaligned_le32(p32));
 296                p32++;
 297                state->v3 = xxh32_round(state->v3, get_unaligned_le32(p32));
 298                p32++;
 299                state->v4 = xxh32_round(state->v4, get_unaligned_le32(p32));
 300                p32++;
 301
 302                p += 16-state->memsize;
 303                state->memsize = 0;
 304        }
 305
 306        if (p <= b_end - 16) {
 307                const uint8_t *const limit = b_end - 16;
 308                uint32_t v1 = state->v1;
 309                uint32_t v2 = state->v2;
 310                uint32_t v3 = state->v3;
 311                uint32_t v4 = state->v4;
 312
 313                do {
 314                        v1 = xxh32_round(v1, get_unaligned_le32(p));
 315                        p += 4;
 316                        v2 = xxh32_round(v2, get_unaligned_le32(p));
 317                        p += 4;
 318                        v3 = xxh32_round(v3, get_unaligned_le32(p));
 319                        p += 4;
 320                        v4 = xxh32_round(v4, get_unaligned_le32(p));
 321                        p += 4;
 322                } while (p <= limit);
 323
 324                state->v1 = v1;
 325                state->v2 = v2;
 326                state->v3 = v3;
 327                state->v4 = v4;
 328        }
 329
 330        if (p < b_end) {
 331                memcpy(state->mem32, p, (size_t)(b_end-p));
 332                state->memsize = (uint32_t)(b_end-p);
 333        }
 334
 335        return 0;
 336}
 337EXPORT_SYMBOL(xxh32_update);
 338
 339uint32_t xxh32_digest(const struct xxh32_state *state)
 340{
 341        const uint8_t *p = (const uint8_t *)state->mem32;
 342        const uint8_t *const b_end = (const uint8_t *)(state->mem32) +
 343                state->memsize;
 344        uint32_t h32;
 345
 346        if (state->large_len) {
 347                h32 = xxh_rotl32(state->v1, 1) + xxh_rotl32(state->v2, 7) +
 348                        xxh_rotl32(state->v3, 12) + xxh_rotl32(state->v4, 18);
 349        } else {
 350                h32 = state->v3 /* == seed */ + PRIME32_5;
 351        }
 352
 353        h32 += state->total_len_32;
 354
 355        while (p + 4 <= b_end) {
 356                h32 += get_unaligned_le32(p) * PRIME32_3;
 357                h32 = xxh_rotl32(h32, 17) * PRIME32_4;
 358                p += 4;
 359        }
 360
 361        while (p < b_end) {
 362                h32 += (*p) * PRIME32_5;
 363                h32 = xxh_rotl32(h32, 11) * PRIME32_1;
 364                p++;
 365        }
 366
 367        h32 ^= h32 >> 15;
 368        h32 *= PRIME32_2;
 369        h32 ^= h32 >> 13;
 370        h32 *= PRIME32_3;
 371        h32 ^= h32 >> 16;
 372
 373        return h32;
 374}
 375EXPORT_SYMBOL(xxh32_digest);
 376
 377int xxh64_update(struct xxh64_state *state, const void *input, const size_t len)
 378{
 379        const uint8_t *p = (const uint8_t *)input;
 380        const uint8_t *const b_end = p + len;
 381
 382        if (input == NULL)
 383                return -EINVAL;
 384
 385        state->total_len += len;
 386
 387        if (state->memsize + len < 32) { /* fill in tmp buffer */
 388                memcpy(((uint8_t *)state->mem64) + state->memsize, input, len);
 389                state->memsize += (uint32_t)len;
 390                return 0;
 391        }
 392
 393        if (state->memsize) { /* tmp buffer is full */
 394                uint64_t *p64 = state->mem64;
 395
 396                memcpy(((uint8_t *)p64) + state->memsize, input,
 397                        32 - state->memsize);
 398
 399                state->v1 = xxh64_round(state->v1, get_unaligned_le64(p64));
 400                p64++;
 401                state->v2 = xxh64_round(state->v2, get_unaligned_le64(p64));
 402                p64++;
 403                state->v3 = xxh64_round(state->v3, get_unaligned_le64(p64));
 404                p64++;
 405                state->v4 = xxh64_round(state->v4, get_unaligned_le64(p64));
 406
 407                p += 32 - state->memsize;
 408                state->memsize = 0;
 409        }
 410
 411        if (p + 32 <= b_end) {
 412                const uint8_t *const limit = b_end - 32;
 413                uint64_t v1 = state->v1;
 414                uint64_t v2 = state->v2;
 415                uint64_t v3 = state->v3;
 416                uint64_t v4 = state->v4;
 417
 418                do {
 419                        v1 = xxh64_round(v1, get_unaligned_le64(p));
 420                        p += 8;
 421                        v2 = xxh64_round(v2, get_unaligned_le64(p));
 422                        p += 8;
 423                        v3 = xxh64_round(v3, get_unaligned_le64(p));
 424                        p += 8;
 425                        v4 = xxh64_round(v4, get_unaligned_le64(p));
 426                        p += 8;
 427                } while (p <= limit);
 428
 429                state->v1 = v1;
 430                state->v2 = v2;
 431                state->v3 = v3;
 432                state->v4 = v4;
 433        }
 434
 435        if (p < b_end) {
 436                memcpy(state->mem64, p, (size_t)(b_end-p));
 437                state->memsize = (uint32_t)(b_end - p);
 438        }
 439
 440        return 0;
 441}
 442EXPORT_SYMBOL(xxh64_update);
 443
 444uint64_t xxh64_digest(const struct xxh64_state *state)
 445{
 446        const uint8_t *p = (const uint8_t *)state->mem64;
 447        const uint8_t *const b_end = (const uint8_t *)state->mem64 +
 448                state->memsize;
 449        uint64_t h64;
 450
 451        if (state->total_len >= 32) {
 452                const uint64_t v1 = state->v1;
 453                const uint64_t v2 = state->v2;
 454                const uint64_t v3 = state->v3;
 455                const uint64_t v4 = state->v4;
 456
 457                h64 = xxh_rotl64(v1, 1) + xxh_rotl64(v2, 7) +
 458                        xxh_rotl64(v3, 12) + xxh_rotl64(v4, 18);
 459                h64 = xxh64_merge_round(h64, v1);
 460                h64 = xxh64_merge_round(h64, v2);
 461                h64 = xxh64_merge_round(h64, v3);
 462                h64 = xxh64_merge_round(h64, v4);
 463        } else {
 464                h64  = state->v3 + PRIME64_5;
 465        }
 466
 467        h64 += (uint64_t)state->total_len;
 468
 469        while (p + 8 <= b_end) {
 470                const uint64_t k1 = xxh64_round(0, get_unaligned_le64(p));
 471
 472                h64 ^= k1;
 473                h64 = xxh_rotl64(h64, 27) * PRIME64_1 + PRIME64_4;
 474                p += 8;
 475        }
 476
 477        if (p + 4 <= b_end) {
 478                h64 ^= (uint64_t)(get_unaligned_le32(p)) * PRIME64_1;
 479                h64 = xxh_rotl64(h64, 23) * PRIME64_2 + PRIME64_3;
 480                p += 4;
 481        }
 482
 483        while (p < b_end) {
 484                h64 ^= (*p) * PRIME64_5;
 485                h64 = xxh_rotl64(h64, 11) * PRIME64_1;
 486                p++;
 487        }
 488
 489        h64 ^= h64 >> 33;
 490        h64 *= PRIME64_2;
 491        h64 ^= h64 >> 29;
 492        h64 *= PRIME64_3;
 493        h64 ^= h64 >> 32;
 494
 495        return h64;
 496}
 497EXPORT_SYMBOL(xxh64_digest);
 498
 499MODULE_LICENSE("Dual BSD/GPL");
 500MODULE_DESCRIPTION("xxHash");
 501