1 /* GENERATED SOURCE. DO NOT MODIFY. */ 2 // 2016 and later: Unicode, Inc. and others. 3 // License & terms of use: http://www.unicode.org/copyright.html#License 4 /* 5 ****************************************************************************** 6 * Copyright (C) 1996-2010, International Business Machines Corporation and * 7 * others. All Rights Reserved. * 8 ****************************************************************************** 9 */ 10 11 package android.icu.impl; 12 13 import java.util.Arrays; 14 15 import android.icu.lang.UCharacter; 16 17 /** 18 * Builder class to manipulate and generate a trie. 19 * This is useful for ICU data in primitive types. 20 * Provides a compact way to store information that is indexed by Unicode 21 * values, such as character properties, types, keyboard values, etc. This is 22 * very useful when you have a block of Unicode data that contains significant 23 * values while the rest of the Unicode data is unused in the application or 24 * when you have a lot of redundance, such as where all 21,000 Han ideographs 25 * have the same value. However, lookup is much faster than a hash table. 26 * A trie of any primitive data type serves two purposes: 27 * <UL type = round> 28 * <LI>Fast access of the indexed values. 29 * <LI>Smaller memory footprint. 30 * </UL> 31 * This is a direct port from the ICU4C version 32 * @author Syn Wee Quek 33 * @hide Only a subset of ICU is exposed in Android 34 */ 35 public class TrieBuilder 36 { 37 // public data member ---------------------------------------------- 38 39 /** 40 * Number of data values in a stage 2 (data array) block. 2, 4, 8, .., 41 * 0x200 42 */ 43 public static final int DATA_BLOCK_LENGTH = 1 << Trie.INDEX_STAGE_1_SHIFT_; 44 45 // public class declaration ---------------------------------------- 46 47 /** 48 * Character data in com.ibm.impl.Trie have different user-specified format 49 * for different purposes. 50 * This interface specifies methods to be implemented in order for 51 * com.ibm.impl.Trie, to surrogate offset information encapsulated within 52 * the data. 53 */ 54 public static interface DataManipulate 55 { 56 /** 57 * Build-time trie callback function, used with serialize(). 58 * This function calculates a lead surrogate's value including a 59 * folding offset from the 1024 supplementary code points 60 * [start..start+1024[ . 61 * It is U+10000 <= start <= U+10fc00 and (start&0x3ff)==0. 62 * The folding offset is provided by the caller. 63 * It is offset=UTRIE_BMP_INDEX_LENGTH+n*UTRIE_SURROGATE_BLOCK_COUNT 64 * with n=0..1023. 65 * Instead of the offset itself, n can be stored in 10 bits - or fewer 66 * if it can be assumed that few lead surrogates have associated data. 67 * The returned value must be 68 * - not zero if and only if there is relevant data for the 69 * corresponding 1024 supplementary code points 70 * - such that UTrie.getFoldingOffset(UNewTrieGetFoldedValue(..., 71 * offset))==offset 72 * @return a folded value, or 0 if there is no relevant data for the 73 * lead surrogate. 74 */ 75 public int getFoldedValue(int start, int offset); 76 } 77 78 // public methods ---------------------------------------------------- 79 80 /** 81 * Checks if the character belongs to a zero block in the trie 82 * @param ch codepoint which data is to be retrieved 83 * @return true if ch is in the zero block 84 */ 85 public boolean isInZeroBlock(int ch) 86 { 87 // valid, uncompacted trie and valid c? 88 if (m_isCompacted_ || ch > UCharacter.MAX_VALUE 89 || ch < UCharacter.MIN_VALUE) { 90 return true; 91 } 92 93 return m_index_[ch >> SHIFT_] == 0; 94 } 95 96 // package private method ----------------------------------------------- 97 98 // protected data member ----------------------------------------------- 99 100 /** 101 * Index values at build-time are 32 bits wide for easier processing. 102 * Bit 31 is set if the data block is used by multiple index values 103 * (from setRange()). 104 */ 105 protected int m_index_[]; 106 protected int m_indexLength_; 107 protected int m_dataCapacity_; 108 protected int m_dataLength_; 109 protected boolean m_isLatin1Linear_; 110 protected boolean m_isCompacted_; 111 /** 112 * Map of adjusted indexes, used in utrie_compact(). 113 * Maps from original indexes to new ones. 114 */ 115 protected int m_map_[]; 116 117 /** 118 * Shift size for shifting right the input index. 1..9 119 */ 120 protected static final int SHIFT_ = Trie.INDEX_STAGE_1_SHIFT_; 121 /** 122 * Length of the index (stage 1) array before folding. 123 * Maximum number of Unicode code points (0x110000) shifted right by 124 * SHIFT. 125 */ 126 protected static final int MAX_INDEX_LENGTH_ = (0x110000 >> SHIFT_); 127 /** 128 * Length of the BMP portion of the index (stage 1) array. 129 */ 130 protected static final int BMP_INDEX_LENGTH_ = 0x10000 >> SHIFT_; 131 /** 132 * Number of index (stage 1) entries per lead surrogate. 133 * Same as number of indexe entries for 1024 trail surrogates, 134 * ==0x400>>UTRIE_SHIFT 135 * 10 - SHIFT == Number of bits of a trail surrogate that are used in 136 * index table lookups. 137 */ 138 protected static final int SURROGATE_BLOCK_COUNT_ = 1 << (10 - SHIFT_); 139 /** 140 * Mask for getting the lower bits from the input index. 141 * DATA_BLOCK_LENGTH - 1. 142 */ 143 protected static final int MASK_ = Trie.INDEX_STAGE_3_MASK_; 144 /** 145 * Shift size for shifting left the index array values. 146 * Increases possible data size with 16-bit index values at the cost 147 * of compactability. 148 * This requires blocks of stage 2 data to be aligned by UTRIE_DATA_GRANULARITY. 149 * 0..UTRIE_SHIFT 150 */ 151 protected static final int INDEX_SHIFT_ = Trie.INDEX_STAGE_2_SHIFT_; 152 /** 153 * Maximum length of the runtime data (stage 2) array. 154 * Limited by 16-bit index values that are left-shifted by INDEX_SHIFT_. 155 */ 156 protected static final int MAX_DATA_LENGTH_ = (0x10000 << INDEX_SHIFT_); 157 /** 158 * Shifting to position the index value in options 159 */ 160 protected static final int OPTIONS_INDEX_SHIFT_ = 4; 161 /** 162 * If set, then the data (stage 2) array is 32 bits wide. 163 */ 164 protected static final int OPTIONS_DATA_IS_32_BIT_ = 0x100; 165 /** 166 * If set, then Latin-1 data (for U+0000..U+00ff) is stored in the data 167 * (stage 2) array as a simple, linear array at data + DATA_BLOCK_LENGTH. 168 */ 169 protected static final int OPTIONS_LATIN1_IS_LINEAR_ = 0x200; 170 /** 171 * The alignment size of a stage 2 data block. Also the granularity for 172 * compaction. 173 */ 174 protected static final int DATA_GRANULARITY_ = 1 << INDEX_SHIFT_; 175 176 // protected constructor ---------------------------------------------- 177 178 protected TrieBuilder() 179 { 180 m_index_ = new int[MAX_INDEX_LENGTH_]; 181 m_map_ = new int[MAX_BUILD_TIME_DATA_LENGTH_ >> SHIFT_]; 182 m_isLatin1Linear_ = false; 183 m_isCompacted_ = false; 184 m_indexLength_ = MAX_INDEX_LENGTH_; 185 } 186 187 protected TrieBuilder(TrieBuilder table) 188 { 189 m_index_ = new int[MAX_INDEX_LENGTH_]; 190 m_indexLength_ = table.m_indexLength_; 191 System.arraycopy(table.m_index_, 0, m_index_, 0, m_indexLength_); 192 m_dataCapacity_ = table.m_dataCapacity_; 193 m_dataLength_ = table.m_dataLength_; 194 m_map_ = new int[table.m_map_.length]; 195 System.arraycopy(table.m_map_, 0, m_map_, 0, m_map_.length); 196 m_isLatin1Linear_ = table.m_isLatin1Linear_; 197 m_isCompacted_ = table.m_isCompacted_; 198 } 199 200 // protected functions ------------------------------------------------ 201 202 /** 203 * Compare two sections of an array for equality. 204 */ 205 protected static final boolean equal_int(int[] array, int start1, int start2, int length) { 206 while(length>0 && array[start1]==array[start2]) { 207 ++start1; 208 ++start2; 209 --length; 210 } 211 return length==0; 212 } 213 214 /** 215 * Set a value in the trie index map to indicate which data block 216 * is referenced and which one is not. 217 * utrie_compact() will remove data blocks that are not used at all. 218 * Set 219 * - 0 if it is used 220 * - -1 if it is not used 221 */ 222 protected void findUnusedBlocks() 223 { 224 // fill the entire map with "not used" 225 Arrays.fill(m_map_, 0xff); 226 227 // mark each block that _is_ used with 0 228 for (int i = 0; i < m_indexLength_; ++ i) { 229 m_map_[Math.abs(m_index_[i]) >> SHIFT_] = 0; 230 } 231 232 // never move the all-initial-value block 0 233 m_map_[0] = 0; 234 } 235 236 /** 237 * Finds the same index block as the otherBlock 238 * @param index array 239 * @param indexLength size of index 240 * @param otherBlock 241 * @return same index block 242 */ 243 protected static final int findSameIndexBlock(int index[], int indexLength, 244 int otherBlock) 245 { 246 for (int block = BMP_INDEX_LENGTH_; block < indexLength; 247 block += SURROGATE_BLOCK_COUNT_) { 248 if(equal_int(index, block, otherBlock, SURROGATE_BLOCK_COUNT_)) { 249 return block; 250 } 251 } 252 return indexLength; 253 } 254 255 // private data member ------------------------------------------------ 256 257 /** 258 * Maximum length of the build-time data (stage 2) array. 259 * The maximum length is 0x110000 + DATA_BLOCK_LENGTH + 0x400. 260 * (Number of Unicode code points + one all-initial-value block + 261 * possible duplicate entries for 1024 lead surrogates.) 262 */ 263 private static final int MAX_BUILD_TIME_DATA_LENGTH_ = 264 0x110000 + DATA_BLOCK_LENGTH + 0x400; 265 } 266