1 /*
2 *******************************************************************************
3 * Copyright (C) 2010-2014, International Business Machines
4 * Corporation and others. All Rights Reserved.
5 *******************************************************************************
6 * collation.cpp
7 *
8 * created on: 2010oct27
9 * created by: Markus W. Scherer
10 */
11
12 #include "unicode/utypes.h"
13
14 #if !UCONFIG_NO_COLLATION
15
16 #include "collation.h"
17 #include "uassert.h"
18
19 U_NAMESPACE_BEGIN
20
21 // Some compilers don't care if constants are defined in the .cpp file.
22 // MS Visual C++ does not like it, but gcc requires it. clang does not care.
23 #ifndef _MSC_VER
24 const uint8_t Collation::LEVEL_SEPARATOR_BYTE;
25 const uint8_t Collation::MERGE_SEPARATOR_BYTE;
26 const uint32_t Collation::ONLY_TERTIARY_MASK;
27 const uint32_t Collation::CASE_AND_TERTIARY_MASK;
28 #endif
29
30 uint32_t
incTwoBytePrimaryByOffset(uint32_t basePrimary,UBool isCompressible,int32_t offset)31 Collation::incTwoBytePrimaryByOffset(uint32_t basePrimary, UBool isCompressible, int32_t offset) {
32 // Extract the second byte, minus the minimum byte value,
33 // plus the offset, modulo the number of usable byte values, plus the minimum.
34 // Reserve the PRIMARY_COMPRESSION_LOW_BYTE and high byte if necessary.
35 uint32_t primary;
36 if(isCompressible) {
37 offset += ((int32_t)(basePrimary >> 16) & 0xff) - 4;
38 primary = (uint32_t)((offset % 251) + 4) << 16;
39 offset /= 251;
40 } else {
41 offset += ((int32_t)(basePrimary >> 16) & 0xff) - 2;
42 primary = (uint32_t)((offset % 254) + 2) << 16;
43 offset /= 254;
44 }
45 // First byte, assume no further overflow.
46 return primary | ((basePrimary & 0xff000000) + (uint32_t)(offset << 24));
47 }
48
49 uint32_t
incThreeBytePrimaryByOffset(uint32_t basePrimary,UBool isCompressible,int32_t offset)50 Collation::incThreeBytePrimaryByOffset(uint32_t basePrimary, UBool isCompressible, int32_t offset) {
51 // Extract the third byte, minus the minimum byte value,
52 // plus the offset, modulo the number of usable byte values, plus the minimum.
53 offset += ((int32_t)(basePrimary >> 8) & 0xff) - 2;
54 uint32_t primary = (uint32_t)((offset % 254) + 2) << 8;
55 offset /= 254;
56 // Same with the second byte,
57 // but reserve the PRIMARY_COMPRESSION_LOW_BYTE and high byte if necessary.
58 if(isCompressible) {
59 offset += ((int32_t)(basePrimary >> 16) & 0xff) - 4;
60 primary |= (uint32_t)((offset % 251) + 4) << 16;
61 offset /= 251;
62 } else {
63 offset += ((int32_t)(basePrimary >> 16) & 0xff) - 2;
64 primary |= (uint32_t)((offset % 254) + 2) << 16;
65 offset /= 254;
66 }
67 // First byte, assume no further overflow.
68 return primary | ((basePrimary & 0xff000000) + (uint32_t)(offset << 24));
69 }
70
71 uint32_t
decTwoBytePrimaryByOneStep(uint32_t basePrimary,UBool isCompressible,int32_t step)72 Collation::decTwoBytePrimaryByOneStep(uint32_t basePrimary, UBool isCompressible, int32_t step) {
73 // Extract the second byte, minus the minimum byte value,
74 // minus the step, modulo the number of usable byte values, plus the minimum.
75 // Reserve the PRIMARY_COMPRESSION_LOW_BYTE and high byte if necessary.
76 // Assume no further underflow for the first byte.
77 U_ASSERT(0 < step && step <= 0x7f);
78 int32_t byte2 = ((int32_t)(basePrimary >> 16) & 0xff) - step;
79 if(isCompressible) {
80 if(byte2 < 4) {
81 byte2 += 251;
82 basePrimary -= 0x1000000;
83 }
84 } else {
85 if(byte2 < 2) {
86 byte2 += 254;
87 basePrimary -= 0x1000000;
88 }
89 }
90 return (basePrimary & 0xff000000) | ((uint32_t)byte2 << 16);
91 }
92
93 uint32_t
decThreeBytePrimaryByOneStep(uint32_t basePrimary,UBool isCompressible,int32_t step)94 Collation::decThreeBytePrimaryByOneStep(uint32_t basePrimary, UBool isCompressible, int32_t step) {
95 // Extract the third byte, minus the minimum byte value,
96 // minus the step, modulo the number of usable byte values, plus the minimum.
97 U_ASSERT(0 < step && step <= 0x7f);
98 int32_t byte3 = ((int32_t)(basePrimary >> 8) & 0xff) - step;
99 if(byte3 >= 2) {
100 return (basePrimary & 0xffff0000) | ((uint32_t)byte3 << 8);
101 }
102 byte3 += 254;
103 // Same with the second byte,
104 // but reserve the PRIMARY_COMPRESSION_LOW_BYTE and high byte if necessary.
105 int32_t byte2 = ((int32_t)(basePrimary >> 16) & 0xff) - 1;
106 if(isCompressible) {
107 if(byte2 < 4) {
108 byte2 = 0xfe;
109 basePrimary -= 0x1000000;
110 }
111 } else {
112 if(byte2 < 2) {
113 byte2 = 0xff;
114 basePrimary -= 0x1000000;
115 }
116 }
117 // First byte, assume no further underflow.
118 return (basePrimary & 0xff000000) | ((uint32_t)byte2 << 16) | ((uint32_t)byte3 << 8);
119 }
120
121 uint32_t
getThreeBytePrimaryForOffsetData(UChar32 c,int64_t dataCE)122 Collation::getThreeBytePrimaryForOffsetData(UChar32 c, int64_t dataCE) {
123 uint32_t p = (uint32_t)(dataCE >> 32); // three-byte primary pppppp00
124 int32_t lower32 = (int32_t)dataCE; // base code point b & step s: bbbbbbss (bit 7: isCompressible)
125 int32_t offset = (c - (lower32 >> 8)) * (lower32 & 0x7f); // delta * increment
126 UBool isCompressible = (lower32 & 0x80) != 0;
127 return Collation::incThreeBytePrimaryByOffset(p, isCompressible, offset);
128 }
129
130 uint32_t
unassignedPrimaryFromCodePoint(UChar32 c)131 Collation::unassignedPrimaryFromCodePoint(UChar32 c) {
132 // Create a gap before U+0000. Use c=-1 for [first unassigned].
133 ++c;
134 // Fourth byte: 18 values, every 14th byte value (gap of 13).
135 uint32_t primary = 2 + (c % 18) * 14;
136 c /= 18;
137 // Third byte: 254 values.
138 primary |= (2 + (c % 254)) << 8;
139 c /= 254;
140 // Second byte: 251 values 04..FE excluding the primary compression bytes.
141 primary |= (4 + (c % 251)) << 16;
142 // One lead byte covers all code points (c < 0x1182B4 = 1*251*254*18).
143 return primary | (UNASSIGNED_IMPLICIT_BYTE << 24);
144 }
145
146 U_NAMESPACE_END
147
148 #endif // !UCONFIG_NO_COLLATION
149