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comparison: intl/icu/source/common/utrie2_impl.h

intl/icu/source/common/utrie2_impl.h

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1 /*
2 ******************************************************************************
3 *
4 * Copyright (C) 2001-2008, International Business Machines
5 * Corporation and others. All Rights Reserved.
6 *
7 ******************************************************************************
8 * file name: utrie2_impl.h
9 * encoding: US-ASCII
10 * tab size: 8 (not used)
11 * indentation:4
12 *
13 * created on: 2008sep26 (split off from utrie2.c)
14 * created by: Markus W. Scherer
15 *
16 * Definitions needed for both runtime and builder code for UTrie2,
17 * used by utrie2.c and utrie2_builder.c.
18 */
19
20 #ifndef __UTRIE2_IMPL_H__
21 #define __UTRIE2_IMPL_H__
22
23 #include "utrie2.h"
24
25 /* Public UTrie2 API implementation ----------------------------------------- */
26
27 /*
28 * These definitions are mostly needed by utrie2.c,
29 * but also by utrie2_serialize() and utrie2_swap().
30 */
31
32 /*
33 * UTrie and UTrie2 signature values,
34 * in platform endianness and opposite endianness.
35 */
36 #define UTRIE_SIG 0x54726965
37 #define UTRIE_OE_SIG 0x65697254
38
39 #define UTRIE2_SIG 0x54726932
40 #define UTRIE2_OE_SIG 0x32697254
41
42 /**
43 * Trie data structure in serialized form:
44 *
45 * UTrie2Header header;
46 * uint16_t index[header.index2Length];
47 * uint16_t data[header.shiftedDataLength<<2]; -- or uint32_t data[...]
48 * @internal
49 */
50 typedef struct UTrie2Header {
51 /** "Tri2" in big-endian US-ASCII (0x54726932) */
52 uint32_t signature;
53
54 /**
55 * options bit field:
56 * 15.. 4 reserved (0)
57 * 3.. 0 UTrie2ValueBits valueBits
58 */
59 uint16_t options;
60
61 /** UTRIE2_INDEX_1_OFFSET..UTRIE2_MAX_INDEX_LENGTH */
62 uint16_t indexLength;
63
64 /** (UTRIE2_DATA_START_OFFSET..UTRIE2_MAX_DATA_LENGTH)>>UTRIE2_INDEX_SHIFT */
65 uint16_t shiftedDataLength;
66
67 /** Null index and data blocks, not shifted. */
68 uint16_t index2NullOffset, dataNullOffset;
69
70 /**
71 * First code point of the single-value range ending with U+10ffff,
72 * rounded up and then shifted right by UTRIE2_SHIFT_1.
73 */
74 uint16_t shiftedHighStart;
75 } UTrie2Header;
76
77 /**
78 * Constants for use with UTrie2Header.options.
79 * @internal
80 */
81 enum {
82 /** Mask to get the UTrie2ValueBits valueBits from options. */
83 UTRIE2_OPTIONS_VALUE_BITS_MASK=0xf
84 };
85
86 /* Building a trie ---------------------------------------------------------- */
87
88 /*
89 * These definitions are mostly needed by utrie2_builder.c, but also by
90 * utrie2_get32() and utrie2_enum().
91 */
92
93 enum {
94 /**
95 * At build time, leave a gap in the index-2 table,
96 * at least as long as the maximum lengths of the 2-byte UTF-8 index-2 table
97 * and the supplementary index-1 table.
98 * Round up to UTRIE2_INDEX_2_BLOCK_LENGTH for proper compacting.
99 */
100 UNEWTRIE2_INDEX_GAP_OFFSET=UTRIE2_INDEX_2_BMP_LENGTH,
101 UNEWTRIE2_INDEX_GAP_LENGTH=
102 ((UTRIE2_UTF8_2B_INDEX_2_LENGTH+UTRIE2_MAX_INDEX_1_LENGTH)+UTRIE2_INDEX_2_MASK)&
103 ~UTRIE2_INDEX_2_MASK,
104
105 /**
106 * Maximum length of the build-time index-2 array.
107 * Maximum number of Unicode code points (0x110000) shifted right by UTRIE2_SHIFT_2,
108 * plus the part of the index-2 table for lead surrogate code points,
109 * plus the build-time index gap,
110 * plus the null index-2 block.
111 */
112 UNEWTRIE2_MAX_INDEX_2_LENGTH=
113 (0x110000>>UTRIE2_SHIFT_2)+
114 UTRIE2_LSCP_INDEX_2_LENGTH+
115 UNEWTRIE2_INDEX_GAP_LENGTH+
116 UTRIE2_INDEX_2_BLOCK_LENGTH,
117
118 UNEWTRIE2_INDEX_1_LENGTH=0x110000>>UTRIE2_SHIFT_1
119 };
120
121 /**
122 * Maximum length of the build-time data array.
123 * One entry per 0x110000 code points, plus the illegal-UTF-8 block and the null block,
124 * plus values for the 0x400 surrogate code units.
125 */
126 #define UNEWTRIE2_MAX_DATA_LENGTH (0x110000+0x40+0x40+0x400)
127
128 /*
129 * Build-time trie structure.
130 *
131 * Just using a boolean flag for "repeat use" could lead to data array overflow
132 * because we would not be able to detect when a data block becomes unused.
133 * It also leads to orphan data blocks that are kept through serialization.
134 *
135 * Need to use reference counting for data blocks,
136 * and allocDataBlock() needs to look for a free block before increasing dataLength.
137 *
138 * This scheme seems like overkill for index-2 blocks since the whole index array is
139 * preallocated anyway (unlike the growable data array).
140 * Just allocating multiple index-2 blocks as needed.
141 */
142 struct UNewTrie2 {
143 int32_t index1[UNEWTRIE2_INDEX_1_LENGTH];
144 int32_t index2[UNEWTRIE2_MAX_INDEX_2_LENGTH];
145 uint32_t *data;
146
147 uint32_t initialValue, errorValue;
148 int32_t index2Length, dataCapacity, dataLength;
149 int32_t firstFreeBlock;
150 int32_t index2NullOffset, dataNullOffset;
151 UChar32 highStart;
152 UBool isCompacted;
153
154 /**
155 * Multi-purpose per-data-block table.
156 *
157 * Before compacting:
158 *
159 * Per-data-block reference counters/free-block list.
160 * 0: unused
161 * >0: reference counter (number of index-2 entries pointing here)
162 * <0: next free data block in free-block list
163 *
164 * While compacting:
165 *
166 * Map of adjusted indexes, used in compactData() and compactIndex2().
167 * Maps from original indexes to new ones.
168 */
169 int32_t map[UNEWTRIE2_MAX_DATA_LENGTH>>UTRIE2_SHIFT_2];
170 };
171
172 #endif

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