aboutsummaryrefslogtreecommitdiffhomepage
path: root/src/common/hash.cpp
blob: e2364d700ce4c23b1e24131253fda1b84dc7f494 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
// Copyright 2013 Dolphin Emulator Project / 2014 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.

#include <algorithm>

#include "common/common_funcs.h" // For rotl
#include "common/hash.h"
#include "common/platform.h"

#if _M_SSE >= 0x402
#include "common/cpu_detect.h"
#include <nmmintrin.h>
#endif

static u64 (*ptrHashFunction)(const u8 *src, int len, u32 samples) = &GetMurmurHash3;

// uint32_t
// WARNING - may read one more byte!
// Implementation from Wikipedia.
u32 HashFletcher(const u8* data_u8, size_t length)
{
    const u16* data = (const u16*)data_u8; /* Pointer to the data to be summed */
    size_t len = (length + 1) / 2; /* Length in 16-bit words */
    u32 sum1 = 0xffff, sum2 = 0xffff;

    while (len)
    {
        size_t tlen = len > 360 ? 360 : len;
        len -= tlen;

        do {
            sum1 += *data++;
            sum2 += sum1;
        }
        while (--tlen);

        sum1 = (sum1 & 0xffff) + (sum1 >> 16);
        sum2 = (sum2 & 0xffff) + (sum2 >> 16);
    }

    // Second reduction step to reduce sums to 16 bits
    sum1 = (sum1 & 0xffff) + (sum1 >> 16);
    sum2 = (sum2 & 0xffff) + (sum2 >> 16);
    return(sum2 << 16 | sum1);
}


// Implementation from Wikipedia
// Slightly slower than Fletcher above, but slightly more reliable.
#define MOD_ADLER 65521
// data: Pointer to the data to be summed; len is in bytes
u32 HashAdler32(const u8* data, size_t len)
{
    u32 a = 1, b = 0;

    while (len)
    {
        size_t tlen = len > 5550 ? 5550 : len;
        len -= tlen;

        do
        {
            a += *data++;
            b += a;
        }
        while (--tlen);

        a = (a & 0xffff) + (a >> 16) * (65536 - MOD_ADLER);
        b = (b & 0xffff) + (b >> 16) * (65536 - MOD_ADLER);
    }

    // It can be shown that a <= 0x1013a here, so a single subtract will do.
    if (a >= MOD_ADLER)
    {
        a -= MOD_ADLER;
    }

    // It can be shown that b can reach 0xfff87 here.
    b = (b & 0xffff) + (b >> 16) * (65536 - MOD_ADLER);

    if (b >= MOD_ADLER)
    {
        b -= MOD_ADLER;
    }

    return((b << 16) | a);
}

// Stupid hash - but can't go back now :)
// Don't use for new things. At least it's reasonably fast.
u32 HashEctor(const u8* ptr, int length)
{
    u32 crc = 0;

    for (int i = 0; i < length; i++)
    {
        crc ^= ptr[i];
        crc = (crc << 3) | (crc >> 29);
    }

    return(crc);
}


#if EMU_ARCH_BITS == 64

//-----------------------------------------------------------------------------
// Block read - if your platform needs to do endian-swapping or can only
// handle aligned reads, do the conversion here

inline u64 getblock(const u64 * p, int i)
{
    return p[i];
}

//----------
// Block mix - combine the key bits with the hash bits and scramble everything

inline void bmix64(u64 & h1, u64 & h2, u64 & k1, u64 & k2, u64 & c1, u64 & c2)
{
    k1 *= c1;
    k1  = _rotl64(k1,23);
    k1 *= c2;
    h1 ^= k1;
    h1 += h2;

    h2 = _rotl64(h2,41);

    k2 *= c2;
    k2  = _rotl64(k2,23);
    k2 *= c1;
    h2 ^= k2;
    h2 += h1;

    h1 = h1*3+0x52dce729;
    h2 = h2*3+0x38495ab5;

    c1 = c1*5+0x7b7d159c;
    c2 = c2*5+0x6bce6396;
}

//----------
// Finalization mix - avalanches all bits to within 0.05% bias

inline u64 fmix64(u64 k)
{
    k ^= k >> 33;
    k *= 0xff51afd7ed558ccd;
    k ^= k >> 33;
    k *= 0xc4ceb9fe1a85ec53;
    k ^= k >> 33;

    return k;
}

u64 GetMurmurHash3(const u8 *src, int len, u32 samples)
{
    const u8 * data = (const u8*)src;
    const int nblocks = len / 16;
    u32 Step = (len / 8);
    if(samples == 0) samples = std::max(Step, 1u);
    Step = Step / samples;
    if(Step < 1) Step = 1;

    u64 h1 = 0x9368e53c2f6af274;
    u64 h2 = 0x586dcd208f7cd3fd;

    u64 c1 = 0x87c37b91114253d5;
    u64 c2 = 0x4cf5ad432745937f;


    //----------
    // body

    const u64 * blocks = (const u64 *)(data);

    for(int i = 0; i < nblocks; i+=Step)
    {
        u64 k1 = getblock(blocks,i*2+0);
        u64 k2 = getblock(blocks,i*2+1);

        bmix64(h1,h2,k1,k2,c1,c2);
    }

    //----------
    // tail

    const u8 * tail = (const u8*)(data + nblocks*16);

    u64 k1 = 0;
    u64 k2 = 0;

    switch(len & 15)
    {
    case 15: k2 ^= u64(tail[14]) << 48;
    case 14: k2 ^= u64(tail[13]) << 40;
    case 13: k2 ^= u64(tail[12]) << 32;
    case 12: k2 ^= u64(tail[11]) << 24;
    case 11: k2 ^= u64(tail[10]) << 16;
    case 10: k2 ^= u64(tail[ 9]) << 8;
    case  9: k2 ^= u64(tail[ 8]) << 0;

    case  8: k1 ^= u64(tail[ 7]) << 56;
    case  7: k1 ^= u64(tail[ 6]) << 48;
    case  6: k1 ^= u64(tail[ 5]) << 40;
    case  5: k1 ^= u64(tail[ 4]) << 32;
    case  4: k1 ^= u64(tail[ 3]) << 24;
    case  3: k1 ^= u64(tail[ 2]) << 16;
    case  2: k1 ^= u64(tail[ 1]) << 8;
    case  1: k1 ^= u64(tail[ 0]) << 0;
            bmix64(h1,h2,k1,k2,c1,c2);
    };

    //----------
    // finalization

    h2 ^= len;

    h1 += h2;
    h2 += h1;

    h1 = fmix64(h1);
    h2 = fmix64(h2);

    h1 += h2;

    return h1;
}


// CRC32 hash using the SSE4.2 instruction
u64 GetCRC32(const u8 *src, int len, u32 samples)
{
#if _M_SSE >= 0x402
    u64 h = len;
    u32 Step = (len / 8);
    const u64 *data = (const u64 *)src;
    const u64 *end = data + Step;
    if(samples == 0) samples = std::max(Step, 1u);
    Step = Step / samples;
    if(Step < 1) Step = 1;
    while(data < end)
    {
        h = _mm_crc32_u64(h, data[0]);
        data += Step;
    }

    const u8 *data2 = (const u8*)end;
    return _mm_crc32_u64(h, u64(data2[0]));
#else
    return 0;
#endif
}


/*
 * NOTE: This hash function is used for custom texture loading/dumping, so
 * it should not be changed, which would require all custom textures to be
 * recalculated for their new hash values. If the hashing function is
 * changed, make sure this one is still used when the legacy parameter is
 * true.
 */
u64 GetHashHiresTexture(const u8 *src, int len, u32 samples)
{
    const u64 m = 0xc6a4a7935bd1e995;
    u64 h = len * m;
    const int r = 47;
    u32 Step = (len / 8);
    const u64 *data = (const u64 *)src;
    const u64 *end = data + Step;
    if(samples == 0) samples = std::max(Step, 1u);
    Step = Step / samples;
    if(Step < 1) Step = 1;
    while(data < end)
    {
        u64 k = data[0];
        data+=Step;
        k *= m;
        k ^= k >> r;
        k *= m;
        h ^= k;
        h *= m;
    }

    const u8 * data2 = (const u8*)end;

    switch(len & 7)
    {
    case 7: h ^= u64(data2[6]) << 48;
    case 6: h ^= u64(data2[5]) << 40;
    case 5: h ^= u64(data2[4]) << 32;
    case 4: h ^= u64(data2[3]) << 24;
    case 3: h ^= u64(data2[2]) << 16;
    case 2: h ^= u64(data2[1]) << 8;
    case 1: h ^= u64(data2[0]);
            h *= m;
    };

    h ^= h >> r;
    h *= m;
    h ^= h >> r;

    return h;
}
#else
// CRC32 hash using the SSE4.2 instruction
u64 GetCRC32(const u8 *src, int len, u32 samples)
{
#if _M_SSE >= 0x402
    u32 h = len;
    u32 Step = (len/4);
    const u32 *data = (const u32 *)src;
    const u32 *end = data + Step;
    if(samples == 0) samples = std::max(Step, 1u);
    Step  = Step / samples;
    if(Step < 1) Step = 1;
    while(data < end)
    {
        h = _mm_crc32_u32(h, data[0]);
        data += Step;
    }

    const u8 *data2 = (const u8*)end;
    return (u64)_mm_crc32_u32(h, u32(data2[0]));
#else
    return 0;
#endif
}

//-----------------------------------------------------------------------------
// Block read - if your platform needs to do endian-swapping or can only
// handle aligned reads, do the conversion here

inline u32 getblock(const u32 * p, int i)
{
    return p[i];
}

//----------
// Finalization mix - force all bits of a hash block to avalanche

// avalanches all bits to within 0.25% bias

inline u32 fmix32(u32 h)
{
    h ^= h >> 16;
    h *= 0x85ebca6b;
    h ^= h >> 13;
    h *= 0xc2b2ae35;
    h ^= h >> 16;

    return h;
}

inline void bmix32(u32 & h1, u32 & h2, u32 & k1, u32 & k2, u32 & c1, u32 & c2)
{
    k1 *= c1;
    k1  = _rotl(k1,11);
    k1 *= c2;
    h1 ^= k1;
    h1 += h2;

    h2 = _rotl(h2,17);

    k2 *= c2;
    k2  = _rotl(k2,11);
    k2 *= c1;
    h2 ^= k2;
    h2 += h1;

    h1 = h1*3+0x52dce729;
    h2 = h2*3+0x38495ab5;

    c1 = c1*5+0x7b7d159c;
    c2 = c2*5+0x6bce6396;
}

//----------

u64 GetMurmurHash3(const u8* src, int len, u32 samples)
{
    const u8 * data = (const u8*)src;
    u32 out[2];
    const int nblocks = len / 8;
    u32 Step = (len / 4);
    if(samples == 0) samples = std::max(Step, 1u);
    Step = Step / samples;
    if(Step < 1) Step = 1;

    u32 h1 = 0x8de1c3ac;
    u32 h2 = 0xbab98226;

    u32 c1 = 0x95543787;
    u32 c2 = 0x2ad7eb25;

    //----------
    // body

    const u32 * blocks = (const u32 *)(data + nblocks*8);

    for(int i = -nblocks; i < 0; i+=Step)
    {
        u32 k1 = getblock(blocks,i*2+0);
        u32 k2 = getblock(blocks,i*2+1);

        bmix32(h1,h2,k1,k2,c1,c2);
    }

    //----------
    // tail

    const u8 * tail = (const u8*)(data + nblocks*8);

    u32 k1 = 0;
    u32 k2 = 0;

    switch(len & 7)
    {
    case 7: k2 ^= tail[6] << 16;
    case 6: k2 ^= tail[5] << 8;
    case 5: k2 ^= tail[4] << 0;
    case 4: k1 ^= tail[3] << 24;
    case 3: k1 ^= tail[2] << 16;
    case 2: k1 ^= tail[1] << 8;
    case 1: k1 ^= tail[0] << 0;
            bmix32(h1,h2,k1,k2,c1,c2);
    };

    //----------
    // finalization

    h2 ^= len;

    h1 += h2;
    h2 += h1;

    h1 = fmix32(h1);
    h2 = fmix32(h2);

    h1 += h2;
    h2 += h1;

    out[0] = h1;
    out[1] = h2;

    return *((u64 *)&out);
}

/*
 * FIXME: The old 32-bit version of this hash made different hashes than the
 * 64-bit version. Until someone can make a new version of the 32-bit one that
 * makes identical hashes, this is just a c/p of the 64-bit one.
 */
u64 GetHashHiresTexture(const u8 *src, int len, u32 samples)
{
    const u64 m = 0xc6a4a7935bd1e995ULL;
    u64 h = len * m;
    const int r = 47;
    u32 Step = (len / 8);
    const u64 *data = (const u64 *)src;
    const u64 *end = data + Step;
    if(samples == 0) samples = std::max(Step, 1u);
    Step = Step / samples;
    if(Step < 1) Step = 1;
    while(data < end)
    {
        u64 k = data[0];
        data+=Step;
        k *= m;
        k ^= k >> r;
        k *= m;
        h ^= k;
        h *= m;
    }

    const u8 * data2 = (const u8*)end;

    switch(len & 7)
    {
    case 7: h ^= u64(data2[6]) << 48;
    case 6: h ^= u64(data2[5]) << 40;
    case 5: h ^= u64(data2[4]) << 32;
    case 4: h ^= u64(data2[3]) << 24;
    case 3: h ^= u64(data2[2]) << 16;
    case 2: h ^= u64(data2[1]) << 8;
    case 1: h ^= u64(data2[0]);
            h *= m;
    };

    h ^= h >> r;
    h *= m;
    h ^= h >> r;

    return h;
}
#endif

u64 GetHash64(const u8 *src, int len, u32 samples)
{
    return ptrHashFunction(src, len, samples);
}

// sets the hash function used for the texture cache
void SetHash64Function(bool useHiresTextures)
{
    if (useHiresTextures)
    {
        ptrHashFunction = &GetHashHiresTexture;
    }
#if _M_SSE >= 0x402
    else if (cpu_info.bSSE4_2 && !useHiresTextures) // sse crc32 version
    {
        ptrHashFunction = &GetCRC32;
    }
#endif
    else
    {
        ptrHashFunction = &GetMurmurHash3;
    }
}