1 // © 2016 and later: Unicode, Inc. and others.
2 // License & terms of use: http://www.unicode.org/copyright.html
3 /*
4 *******************************************************************************
5 * Copyright (C) 2010-2014, International Business Machines
6 * Corporation and others. All Rights Reserved.
7 *******************************************************************************
8 * collation.cpp
9 *
10 * created on: 2010oct27
11 * created by: Markus W. Scherer
12 */
13
14 #include "unicode/utypes.h"
15
16 #if !UCONFIG_NO_COLLATION
17
18 #include "collation.h"
19 #include "uassert.h"
20
21 U_NAMESPACE_BEGIN
22
23 uint32_t
incTwoBytePrimaryByOffset(uint32_t basePrimary,UBool isCompressible,int32_t offset)24 Collation::incTwoBytePrimaryByOffset(uint32_t basePrimary, UBool isCompressible, int32_t offset) {
25 // Extract the second byte, minus the minimum byte value,
26 // plus the offset, modulo the number of usable byte values, plus the minimum.
27 // Reserve the PRIMARY_COMPRESSION_LOW_BYTE and high byte if necessary.
28 uint32_t primary;
29 if(isCompressible) {
30 offset += ((int32_t)(basePrimary >> 16) & 0xff) - 4;
31 primary = (uint32_t)((offset % 251) + 4) << 16;
32 offset /= 251;
33 } else {
34 offset += ((int32_t)(basePrimary >> 16) & 0xff) - 2;
35 primary = (uint32_t)((offset % 254) + 2) << 16;
36 offset /= 254;
37 }
38 // First byte, assume no further overflow.
39 return primary | ((basePrimary & 0xff000000) + (uint32_t)(offset << 24));
40 }
41
42 uint32_t
incThreeBytePrimaryByOffset(uint32_t basePrimary,UBool isCompressible,int32_t offset)43 Collation::incThreeBytePrimaryByOffset(uint32_t basePrimary, UBool isCompressible, int32_t offset) {
44 // Extract the third byte, minus the minimum byte value,
45 // plus the offset, modulo the number of usable byte values, plus the minimum.
46 offset += ((int32_t)(basePrimary >> 8) & 0xff) - 2;
47 uint32_t primary = (uint32_t)((offset % 254) + 2) << 8;
48 offset /= 254;
49 // Same with the second byte,
50 // but reserve the PRIMARY_COMPRESSION_LOW_BYTE and high byte if necessary.
51 if(isCompressible) {
52 offset += ((int32_t)(basePrimary >> 16) & 0xff) - 4;
53 primary |= (uint32_t)((offset % 251) + 4) << 16;
54 offset /= 251;
55 } else {
56 offset += ((int32_t)(basePrimary >> 16) & 0xff) - 2;
57 primary |= (uint32_t)((offset % 254) + 2) << 16;
58 offset /= 254;
59 }
60 // First byte, assume no further overflow.
61 return primary | ((basePrimary & 0xff000000) + (uint32_t)(offset << 24));
62 }
63
64 uint32_t
decTwoBytePrimaryByOneStep(uint32_t basePrimary,UBool isCompressible,int32_t step)65 Collation::decTwoBytePrimaryByOneStep(uint32_t basePrimary, UBool isCompressible, int32_t step) {
66 // Extract the second byte, minus the minimum byte value,
67 // minus the step, modulo the number of usable byte values, plus the minimum.
68 // Reserve the PRIMARY_COMPRESSION_LOW_BYTE and high byte if necessary.
69 // Assume no further underflow for the first byte.
70 U_ASSERT(0 < step && step <= 0x7f);
71 int32_t byte2 = ((int32_t)(basePrimary >> 16) & 0xff) - step;
72 if(isCompressible) {
73 if(byte2 < 4) {
74 byte2 += 251;
75 basePrimary -= 0x1000000;
76 }
77 } else {
78 if(byte2 < 2) {
79 byte2 += 254;
80 basePrimary -= 0x1000000;
81 }
82 }
83 return (basePrimary & 0xff000000) | ((uint32_t)byte2 << 16);
84 }
85
86 uint32_t
decThreeBytePrimaryByOneStep(uint32_t basePrimary,UBool isCompressible,int32_t step)87 Collation::decThreeBytePrimaryByOneStep(uint32_t basePrimary, UBool isCompressible, int32_t step) {
88 // Extract the third byte, minus the minimum byte value,
89 // minus the step, modulo the number of usable byte values, plus the minimum.
90 U_ASSERT(0 < step && step <= 0x7f);
91 int32_t byte3 = ((int32_t)(basePrimary >> 8) & 0xff) - step;
92 if(byte3 >= 2) {
93 return (basePrimary & 0xffff0000) | ((uint32_t)byte3 << 8);
94 }
95 byte3 += 254;
96 // Same with the second byte,
97 // but reserve the PRIMARY_COMPRESSION_LOW_BYTE and high byte if necessary.
98 int32_t byte2 = ((int32_t)(basePrimary >> 16) & 0xff) - 1;
99 if(isCompressible) {
100 if(byte2 < 4) {
101 byte2 = 0xfe;
102 basePrimary -= 0x1000000;
103 }
104 } else {
105 if(byte2 < 2) {
106 byte2 = 0xff;
107 basePrimary -= 0x1000000;
108 }
109 }
110 // First byte, assume no further underflow.
111 return (basePrimary & 0xff000000) | ((uint32_t)byte2 << 16) | ((uint32_t)byte3 << 8);
112 }
113
114 uint32_t
getThreeBytePrimaryForOffsetData(UChar32 c,int64_t dataCE)115 Collation::getThreeBytePrimaryForOffsetData(UChar32 c, int64_t dataCE) {
116 uint32_t p = (uint32_t)(dataCE >> 32); // three-byte primary pppppp00
117 int32_t lower32 = (int32_t)dataCE; // base code point b & step s: bbbbbbss (bit 7: isCompressible)
118 int32_t offset = (c - (lower32 >> 8)) * (lower32 & 0x7f); // delta * increment
119 UBool isCompressible = (lower32 & 0x80) != 0;
120 return Collation::incThreeBytePrimaryByOffset(p, isCompressible, offset);
121 }
122
123 uint32_t
unassignedPrimaryFromCodePoint(UChar32 c)124 Collation::unassignedPrimaryFromCodePoint(UChar32 c) {
125 // Create a gap before U+0000. Use c=-1 for [first unassigned].
126 ++c;
127 // Fourth byte: 18 values, every 14th byte value (gap of 13).
128 uint32_t primary = 2 + (c % 18) * 14;
129 c /= 18;
130 // Third byte: 254 values.
131 primary |= (2 + (c % 254)) << 8;
132 c /= 254;
133 // Second byte: 251 values 04..FE excluding the primary compression bytes.
134 primary |= (4 + (c % 251)) << 16;
135 // One lead byte covers all code points (c < 0x1182B4 = 1*251*254*18).
136 return primary | (UNASSIGNED_IMPLICIT_BYTE << 24);
137 }
138
139 U_NAMESPACE_END
140
141 #endif // !UCONFIG_NO_COLLATION
142