icuSources/common/dictionarydata.h

   1 /*
   2 *******************************************************************************
   3 * Copyright (C) 2014, International Business Machines
   4 * Corporation and others.  All Rights Reserved.
   5 *******************************************************************************
   6 * dictionarydata.h
   7 *
   8 * created on: 2012may31
   9 * created by: Markus W. Scherer & Maxime Serrano
  10 */
  11
  12 #ifndef __DICTIONARYDATA_H__
  13 #define __DICTIONARYDATA_H__
  14
  15 #include "unicode/utypes.h"
  16
  17 #if !UCONFIG_NO_BREAK_ITERATION
  18
  19 #include "unicode/utext.h"
  20 #include "unicode/udata.h"
  21 #include "udataswp.h"
  22 #include "unicode/uobject.h"
  23 #include "unicode/ustringtrie.h"
  24
  25 U_NAMESPACE_BEGIN
  26
  27 class UCharsTrie;
  28 class BytesTrie;
  29
  30 class U_COMMON_API DictionaryData : public UMemory {
  31 public:
  32     static const int32_t TRIE_TYPE_BYTES; // = 0;
  33     static const int32_t TRIE_TYPE_UCHARS; // = 1;
  34     static const int32_t TRIE_TYPE_MASK; // = 7;
  35     static const int32_t TRIE_HAS_VALUES; // = 8;
  36
  37     static const int32_t TRANSFORM_NONE; // = 0;
  38     static const int32_t TRANSFORM_TYPE_OFFSET; // = 0x1000000;
  39     static const int32_t TRANSFORM_TYPE_MASK; // = 0x7f000000;
  40     static const int32_t TRANSFORM_OFFSET_MASK; // = 0x1fffff;
  41
  42     enum {
  43         // Byte offsets from the start of the data, after the generic header.
  44         IX_STRING_TRIE_OFFSET,
  45         IX_RESERVED1_OFFSET,
  46         IX_RESERVED2_OFFSET,
  47         IX_TOTAL_SIZE,
  48
  49         // Trie type: TRIE_HAS_VALUES | TRIE_TYPE_BYTES etc.
  50         IX_TRIE_TYPE,
  51         // Transform specification: TRANSFORM_TYPE_OFFSET | 0xe00 etc.
  52         IX_TRANSFORM,
  53
  54         IX_RESERVED6,
  55         IX_RESERVED7,
  56         IX_COUNT
  57     };
  58 };
  59
  60 /**
  61  * Wrapper class around generic dictionaries, implementing matches().
  62  * getType() should return a TRIE_TYPE_??? constant from DictionaryData.
  63  *
  64  * All implementations of this interface must be thread-safe if they are to be used inside of the
  65  * dictionary-based break iteration code.
  66  */
  67 class U_COMMON_API DictionaryMatcher : public UMemory {
  68 public:
  69     DictionaryMatcher() {};
  70     virtual ~DictionaryMatcher();
  71     // this should emulate CompactTrieDictionary::matches()
  72     /*  @param text      The text in which to look for matching words. Matching begins
  73      *                   at the current position of the UText.
  74      *  @param maxLength The max length of match to consider. Units are the native indexing
  75      *                   units of the UText.
  76      *  @param limit     Capacity of output arrays, which is also the maximum number of
  77      *                   matching words to be found.
  78      *  @param lengths   output array, filled with the lengths of the matches, in order,
  79      *                   from shortest to longest. Lengths are in native indexing units
  80      *                   of the UText. May be NULL.
  81      *  @param cpLengths output array, filled with the lengths of the matches, in order,
  82      *                   from shortest to longest. Lengths are the number of Unicode code points.
  83      *                   May be NULL.
  84      *  @param values    Output array, filled with the values associated with the words found.
  85      *                   May be NULL.
  86      *  @param prefix    Output parameter, the code point length of the prefix match, even if that
  87      *                   prefix didn't lead to a complete word. Will always be >= the cpLength
  88      *                   of the longest complete word matched. May be NULL.
  89      *  @return          Number of matching words found.
  90      */
  91     virtual int32_t matches(UText *text, int32_t maxLength, int32_t limit,
  92                             int32_t *lengths, int32_t *cpLengths, int32_t *values,
  93                             int32_t *prefix) const = 0;
  94
  95     /** @return DictionaryData::TRIE_TYPE_XYZ */
  96     virtual int32_t getType() const = 0;
  97 };
  98
  99 // Implementation of the DictionaryMatcher interface for a UCharsTrie dictionary
 100 class U_COMMON_API UCharsDictionaryMatcher : public DictionaryMatcher {
 101 public:
 102     // constructs a new UCharsDictionaryMatcher.
 103     // The UDataMemory * will be closed on this object's destruction.
 104     UCharsDictionaryMatcher(const UChar *c, UDataMemory *f) : characters(c), file(f) { }
 105     virtual ~UCharsDictionaryMatcher();
 106     virtual int32_t matches(UText *text, int32_t maxLength, int32_t limit,
 107                             int32_t *lengths, int32_t *cpLengths, int32_t *values,
 108                             int32_t *prefix) const;
 109     virtual int32_t getType() const;
 110 private:
 111     const UChar *characters;
 112     UDataMemory *file;
 113 };
 114
 115 // Implementation of the DictionaryMatcher interface for a BytesTrie dictionary
 116 class U_COMMON_API BytesDictionaryMatcher : public DictionaryMatcher {
 117 public:
 118     // constructs a new BytesTrieDictionaryMatcher
 119     // the transform constant should be the constant read from the file, not a masked version!
 120     // the UDataMemory * fed in here will be closed on this object's destruction
 121     BytesDictionaryMatcher(const char *c, int32_t t, UDataMemory *f)
 122             : characters(c), transformConstant(t), file(f) { }
 123     virtual ~BytesDictionaryMatcher();
 124     virtual int32_t matches(UText *text, int32_t maxLength, int32_t limit,
 125                             int32_t *lengths, int32_t *cpLengths, int32_t *values,
 126                             int32_t *prefix) const;
 127     virtual int32_t getType() const;
 128 private:
 129     UChar32 transform(UChar32 c) const;
 130
 131     const char *characters;
 132     int32_t transformConstant;
 133     UDataMemory *file;
 134 };
 135
 136 U_NAMESPACE_END
 137
 138 U_CAPI int32_t U_EXPORT2
 139 udict_swap(const UDataSwapper *ds, const void *inData, int32_t length, void *outData, UErrorCode *pErrorCode);
 140
 141 /**
 142  * Format of dictionary .dict data files.
 143  * Format version 1.0.
 144  *
 145  * A dictionary .dict data file contains a byte-serialized BytesTrie or
 146  * a UChars-serialized UCharsTrie.
 147  * Such files are used in dictionary-based break iteration (DBBI).
 148  *
 149  * For a BytesTrie, a transformation type is specified for
 150  * transforming Unicode strings into byte sequences.
 151  *
 152  * A .dict file begins with a standard ICU data file header
 153  * (DataHeader, see ucmndata.h and unicode/udata.h).
 154  * The UDataInfo.dataVersion field is currently unused (set to 0.0.0.0).
 155  *
 156  * After the header, the file contains the following parts.
 157  * Constants are defined in the DictionaryData class.
 158  *
 159  * For the data structure of BytesTrie & UCharsTrie see
 160  * http://site.icu-project.org/design/struct/tries
 161  * and the bytestrie.h and ucharstrie.h header files.
 162  *
 163  * int32_t indexes[indexesLength]; -- indexesLength=indexes[IX_STRING_TRIE_OFFSET]/4;
 164  *
 165  *      The first four indexes are byte offsets in ascending order.
 166  *      Each byte offset marks the start of the next part in the data file,
 167  *      and the end of the previous one.
 168  *      When two consecutive byte offsets are the same, then the corresponding part is empty.
 169  *      Byte offsets are offsets from after the header,
 170  *      that is, from the beginning of the indexes[].
 171  *      Each part starts at an offset with proper alignment for its data.
 172  *      If necessary, the previous part may include padding bytes to achieve this alignment.
 173  *
 174  *      trieType=indexes[IX_TRIE_TYPE] defines the trie type.
 175  *      transform=indexes[IX_TRANSFORM] defines the Unicode-to-bytes transformation.
 176  *          If the transformation type is TRANSFORM_TYPE_OFFSET,
 177  *          then the lower 21 bits contain the offset code point.
 178  *          Each code point c is mapped to byte b = (c - offset).
 179  *          Code points outside the range offset..(offset+0xff) cannot be mapped
 180  *          and do not occur in the dictionary.
 181  *
 182  * stringTrie; -- a serialized BytesTrie or UCharsTrie
 183  *
 184  *      The dictionary maps strings to specific values (TRIE_HAS_VALUES bit set in trieType),
 185  *      or it maps all strings to 0 (TRIE_HAS_VALUES bit not set).
 186  */
 187
 188 #endif  /* !UCONFIG_NO_BREAK_ITERATION */
 189 #endif  /* __DICTIONARYDATA_H__ */