1/*
2 * Copyright 2013 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#include "Benchmark.h"
9#include "SkCanvas.h"
10#include "SkChecksum.h"
11#include "SkPaint.h"
12#include "SkString.h"
13#include "SkTemplates.h"
14
15#include "gUniqueGlyphIDs.h"
16#define gUniqueGlyphIDs_Sentinel    0xFFFF
17
18static int count_glyphs(const uint16_t start[]) {
19    const uint16_t* curr = start;
20    while (*curr != gUniqueGlyphIDs_Sentinel) {
21        curr += 1;
22    }
23    return static_cast<int>(curr - start);
24}
25
26class FontCacheBench : public Benchmark {
27public:
28    FontCacheBench()  {}
29
30protected:
31    const char* onGetName() override {
32        return "fontcache";
33    }
34
35    void onDraw(int loops, SkCanvas* canvas) override {
36        SkPaint paint;
37        this->setupPaint(&paint);
38        paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
39
40        const uint16_t* array = gUniqueGlyphIDs;
41        while (*array != gUniqueGlyphIDs_Sentinel) {
42            int count = count_glyphs(array);
43            for (int i = 0; i < loops; ++i) {
44                paint.measureText(array, count * sizeof(uint16_t));
45            }
46            array += count + 1;    // skip the sentinel
47        }
48    }
49
50private:
51    typedef Benchmark INHERITED;
52};
53
54///////////////////////////////////////////////////////////////////////////////
55
56static uint32_t rotr(uint32_t value, unsigned bits) {
57    return (value >> bits) | (value << (32 - bits));
58}
59
60typedef uint32_t (*HasherProc)(uint32_t);
61
62static uint32_t hasher0(uint32_t value) {
63    value = value ^ (value >> 16);
64    return value ^ (value >> 8);
65}
66
67static const struct {
68    const char* fName;
69    HasherProc  fHasher;
70} gRec[] = {
71    { "hasher0",  hasher0 },
72    { "hasher2",  SkChecksum::Mix },
73};
74
75#define kMaxHashBits   12
76#define kMaxHashCount  (1 << kMaxHashBits)
77
78static int count_collisions(const uint16_t array[], int count, HasherProc proc,
79                            unsigned hashMask) {
80    char table[kMaxHashCount];
81    sk_bzero(table, sizeof(table));
82
83    int collisions = 0;
84    for (int i = 0; i < count; ++i) {
85        int index = proc(array[i]) & hashMask;
86        collisions += table[index];
87        table[index] = 1;
88    }
89    return collisions;
90}
91
92static void dump_array(const uint16_t array[], int count) {
93    for (int i = 0; i < count; ++i) {
94        SkDebugf(" %d,", array[i]);
95    }
96    SkDebugf("\n");
97}
98
99class FontCacheEfficiency : public Benchmark {
100public:
101    FontCacheEfficiency()  {
102        if (false) dump_array(nullptr, 0);
103        if (false) rotr(0, 0);
104    }
105
106protected:
107    const char* onGetName() override {
108        return "fontefficiency";
109    }
110
111    void onDraw(int loops, SkCanvas* canvas) override {
112        static bool gDone;
113        if (gDone) {
114            return;
115        }
116        gDone = true;
117
118        for (int hashBits = 6; hashBits <= 12; hashBits += 1) {
119            int hashMask = ((1 << hashBits) - 1);
120            for (int limit = 32; limit <= 1024; limit <<= 1) {
121                for (size_t i = 0; i < SK_ARRAY_COUNT(gRec); ++i) {
122                    int collisions = 0;
123                    int glyphs = 0;
124                    const uint16_t* array = gUniqueGlyphIDs;
125                    while (*array != gUniqueGlyphIDs_Sentinel) {
126                        int count = SkMin32(count_glyphs(array), limit);
127                        collisions += count_collisions(array, count, gRec[i].fHasher, hashMask);
128                        glyphs += count;
129                        array += count + 1;    // skip the sentinel
130                    }
131                    SkDebugf("hashBits [%d] limit [%d] collisions [%d / %d = %1.2g%%] using %s\n", hashBits, limit, collisions, glyphs,
132                             collisions * 100.0 / glyphs, gRec[i].fName);
133                }
134            }
135        }
136    }
137
138private:
139    typedef Benchmark INHERITED;
140};
141
142///////////////////////////////////////////////////////////////////////////////
143
144DEF_BENCH( return new FontCacheBench(); )
145
146// undefine this to run the efficiency test
147//DEF_BENCH( return new FontCacheEfficiency(); )
148