icuSources/test/perf/unisetperf/draft/bitset.cpp

   1 /*
   2 **********************************************************************
   3 *   Copyright (C) 2007, International Business Machines
   4 *   Corporation and others.  All Rights Reserved.
   5 **********************************************************************
   6 *   file name:  bitset.cpp
   7 *   encoding:   US-ASCII
   8 *   tab size:   8 (not used)
   9 *   indentation:4
  10 *
  11 *   created on: 2007jan15
  12 *   created by: Markus Scherer
  13 *
  14 *   Idea for a "compiled", fast, read-only (immutable) version of a UnicodeSet
  15 *   using a folded bit set consisting of a 1k-entry index table and a
  16 *   compacted array of 64-bit words.
  17 *   Uses a simple hash table for compaction.
  18 *   Uses the original set for supplementary code points.
  19 */
  20
  21 #include "unicode/utypes.h"
  22 #include "unicont.h"
  23
  24 /*
  25  * Hash table for up to 1k 64-bit words, for 1 bit per BMP code point.
  26  * Hashes 64-bit words and maps them to 16-bit integers which are
  27  * assigned in order of new incoming words for subsequent storage
  28  * in a contiguous array.
  29  */
  30 struct BMPBitHash : public UObject {
  31     int64_t keys[0x800];  // 2k
  32     uint16_t values[0x800];
  33     uint16_t reverse[0x400];
  34     uint16_t count;
  35     const int32_t prime=1301;  // Less than 2k.
  36
  37     BMPBitHash() : count(0) {
  38         // Fill values[] with 0xffff.
  39         uprv_memset(values, 0xff, sizeof(values));
  40     }
  41
  42     /*
  43      * Map a key to an integer count.
  44      * Map at most 1k=0x400 different keys with this data structure.
  45      */
  46     uint16_t map(int64_t key) {
  47         int32_t hash=(int32_t)(key>>55)&0x1ff;
  48         hash^=(int32_t)(key>>44)&0x7ff;
  49         hash^=(int32_t)(key>>33)&0x7ff;
  50         hash^=(int32_t)(key>>22)&0x7ff;
  51         hash^=(int32_t)(key>>11)&0x7ff;
  52         hash^=(int32_t)key&0x7ff;
  53         for(;;) {
  54             if(values[hash]==0xffff) {
  55                 // Unused slot.
  56                 keys[hash]=key;
  57                 reverse[count]=hash;
  58                 return values[hash]=count++;
  59             } else if(keys[hash]==key) {
  60                 // Found a slot with this key.
  61                 return values[hash];
  62             } else {
  63                 // Used slot with a different key, move to another slot.
  64                 hash=(hash+prime)&0x7ff;
  65             }
  66         }
  67     }
  68
  69     uint16_t countKeys() const { return count; }
  70
  71     /*
  72      * Invert the hash map: Fill an array of length countKeys() with the keys
  73      * indexed by their mapped values.
  74      */
  75     void invert(int64_t *k) const {
  76         uint16_t i;
  77
  78         for(i=0; i<count; ++i) {
  79             k[i]=keys[reverse[i]];
  80         }
  81     }
  82 };
  83
  84 class BitSet : public UObject, public UnicodeContainable {
  85 public:
  86     BitSet(const UnicodeSet &set, UErrorCode &errorCode) : bits(shortBits), restSet(set.clone()) {
  87         if(U_FAILURE(errorCode)) {
  88             return;
  89         }
  90         BMPBitHash *bitHash=new BMPBitHash;
  91         if(bitHash==NULL || restSet==NULL) {
  92             errorCode=U_MEMORY_ALLOCATION_ERROR;
  93             return;
  94         }
  95
  96         UnicodeSetIterator iter(set);
  97         int64_t b;
  98         UChar32 start, end;
  99         int32_t prevIndex, i, j;
 100
 101         b=0;  // Not necessary but makes compilers happy.
 102         prevIndex=-1;
 103         for(;;) {
 104             if(iter.nextRange() && !iter.isString()) {
 105                 start=iter.getCodepoint();
 106                 end=iter.getCodepointEnd();
 107             } else {
 108                 start=0x10000;
 109             }
 110             i=start>>6;
 111             if(prevIndex!=i) {
 112                 // Finish the end of the previous range.
 113                 if(prevIndex<0) {
 114                     prevIndex=0;
 115                 } else {
 116                     index[prevIndex++]=bitHash->map(b);
 117                 }
 118                 // Fill all-zero entries between ranges.
 119                 if(prevIndex<i) {
 120                     uint16_t zero=bitHash->map(0);
 121                     do {
 122                         index[prevIndex++]=zero;
 123                     } while(prevIndex<i);
 124                 }
 125                 b=0;
 126             }
 127             if(start>0xffff) {
 128                 break;
 129             }
 130             b|=~((INT64_C(1)<<(start&0x3f))-1);
 131             j=end>>6;
 132             if(i<j) {
 133                 // Set bits for the start of the range.
 134                 index[i++]=bitHash->map(b);
 135                 // Fill all-one entries inside the range.
 136                 if(i<j) {
 137                     uint16_t all=bitHash->map(INT64_C(0xffffffffffffffff));
 138                     do {
 139                         index[i++]=all;
 140                     } while(i<j);
 141                 }
 142                 b=INT64_C(0xffffffffffffffff);
 143             }
 144             /* i==j */
 145             b&=(INT64_C(1)<<(end&0x3f))-1;
 146             prevIndex=j;
 147         }
 148
 149         if(bitHash->countKeys()>LENGTHOF(shortBits)) {
 150             bits=(int64_t *)uprv_malloc(bitHash->countKeys()*8);
 151         }
 152         if(bits!=NULL) {
 153             bitHash->invert(bits);
 154         } else {
 155             bits=shortBits;
 156             errorCode=U_MEMORY_ALLOCATION_ERROR;
 157             return;
 158         }
 159
 160         latin1Set[0]=(uint32_t)bits[0];
 161         latin1Set[1]=(uint32_t)(bits[0]>>32);
 162         latin1Set[2]=(uint32_t)bits[1];
 163         latin1Set[3]=(uint32_t)(bits[1]>>32);
 164         latin1Set[4]=(uint32_t)bits[2];
 165         latin1Set[5]=(uint32_t)(bits[2]>>32);
 166         latin1Set[6]=(uint32_t)bits[3];
 167         latin1Set[7]=(uint32_t)(bits[3]>>32);
 168
 169         restSet.remove(0, 0xffff);
 170     }
 171
 172     ~BitSet() {
 173         if(bits!=shortBits) {
 174             uprv_free(bits);
 175         }
 176         delete restSet;
 177     }
 178
 179     UBool contains(UChar32 c) const {
 180         if((uint32_t)c<=0xff) {
 181             return (UBool)((latin1Set[c>>5]&((uint32_t)1<<(c&0x1f)))!=0);
 182         } else if((uint32_t)c<0xffff) {
 183             return (UBool)((bits[c>>6]&(INT64_C(1)<<(c&0x3f)))!=0);
 184         } else {
 185             return restSet->contains(c);
 186         }
 187     }
 188
 189 private:
 190     uint16_t index[0x400];
 191     int64_t shortBits[32];
 192     int64_t *bits;
 193
 194     uint32_t latin1Bits[8];
 195
 196     UnicodeSet *restSet;
 197 };