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
19U_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
24const uint32_t Collation::ONLY_TERTIARY_MASK;
25const uint32_t Collation::CASE_AND_TERTIARY_MASK;
26#endif
27
28uint32_t
29Collation::incTwoBytePrimaryByOffset(uint32_t basePrimary, UBool isCompressible, int32_t offset) {
30    // Extract the second byte, minus the minimum byte value,
31    // plus the offset, modulo the number of usable byte values, plus the minimum.
32    // Reserve the PRIMARY_COMPRESSION_LOW_BYTE and high byte if necessary.
33    uint32_t primary;
34    if(isCompressible) {
35        offset += ((int32_t)(basePrimary >> 16) & 0xff) - 4;
36        primary = (uint32_t)((offset % 251) + 4) << 16;
37        offset /= 251;
38    } else {
39        offset += ((int32_t)(basePrimary >> 16) & 0xff) - 2;
40        primary = (uint32_t)((offset % 254) + 2) << 16;
41        offset /= 254;
42    }
43    // First byte, assume no further overflow.
44    return primary | ((basePrimary & 0xff000000) + (uint32_t)(offset << 24));
45}
46
47uint32_t
48Collation::incThreeBytePrimaryByOffset(uint32_t basePrimary, UBool isCompressible, int32_t offset) {
49    // Extract the third byte, minus the minimum byte value,
50    // plus the offset, modulo the number of usable byte values, plus the minimum.
51    offset += ((int32_t)(basePrimary >> 8) & 0xff) - 2;
52    uint32_t primary = (uint32_t)((offset % 254) + 2) << 8;
53    offset /= 254;
54    // Same with the second byte,
55    // but reserve the PRIMARY_COMPRESSION_LOW_BYTE and high byte if necessary.
56    if(isCompressible) {
57        offset += ((int32_t)(basePrimary >> 16) & 0xff) - 4;
58        primary |= (uint32_t)((offset % 251) + 4) << 16;
59        offset /= 251;
60    } else {
61        offset += ((int32_t)(basePrimary >> 16) & 0xff) - 2;
62        primary |= (uint32_t)((offset % 254) + 2) << 16;
63        offset /= 254;
64    }
65    // First byte, assume no further overflow.
66    return primary | ((basePrimary & 0xff000000) + (uint32_t)(offset << 24));
67}
68
69uint32_t
70Collation::decTwoBytePrimaryByOneStep(uint32_t basePrimary, UBool isCompressible, int32_t step) {
71    // Extract the second byte, minus the minimum byte value,
72    // minus the step, modulo the number of usable byte values, plus the minimum.
73    // Reserve the PRIMARY_COMPRESSION_LOW_BYTE and high byte if necessary.
74    // Assume no further underflow for the first byte.
75    U_ASSERT(0 < step && step <= 0x7f);
76    int32_t byte2 = ((int32_t)(basePrimary >> 16) & 0xff) - step;
77    if(isCompressible) {
78        if(byte2 < 4) {
79            byte2 += 251;
80            basePrimary -= 0x1000000;
81        }
82    } else {
83        if(byte2 < 2) {
84            byte2 += 254;
85            basePrimary -= 0x1000000;
86        }
87    }
88    return (basePrimary & 0xff000000) | ((uint32_t)byte2 << 16);
89}
90
91uint32_t
92Collation::decThreeBytePrimaryByOneStep(uint32_t basePrimary, UBool isCompressible, int32_t step) {
93    // Extract the third byte, minus the minimum byte value,
94    // minus the step, modulo the number of usable byte values, plus the minimum.
95    U_ASSERT(0 < step && step <= 0x7f);
96    int32_t byte3 = ((int32_t)(basePrimary >> 8) & 0xff) - step;
97    if(byte3 >= 2) {
98        return (basePrimary & 0xffff0000) | ((uint32_t)byte3 << 8);
99    }
100    byte3 += 254;
101    // Same with the second byte,
102    // but reserve the PRIMARY_COMPRESSION_LOW_BYTE and high byte if necessary.
103    int32_t byte2 = ((int32_t)(basePrimary >> 16) & 0xff) - 1;
104    if(isCompressible) {
105        if(byte2 < 4) {
106            byte2 = 0xfe;
107            basePrimary -= 0x1000000;
108        }
109    } else {
110        if(byte2 < 2) {
111            byte2 = 0xff;
112            basePrimary -= 0x1000000;
113        }
114    }
115    // First byte, assume no further underflow.
116    return (basePrimary & 0xff000000) | ((uint32_t)byte2 << 16) | ((uint32_t)byte3 << 8);
117}
118
119uint32_t
120Collation::getThreeBytePrimaryForOffsetData(UChar32 c, int64_t dataCE) {
121    uint32_t p = (uint32_t)(dataCE >> 32);  // three-byte primary pppppp00
122    int32_t lower32 = (int32_t)dataCE;  // base code point b & step s: bbbbbbss (bit 7: isCompressible)
123    int32_t offset = (c - (lower32 >> 8)) * (lower32 & 0x7f);  // delta * increment
124    UBool isCompressible = (lower32 & 0x80) != 0;
125    return Collation::incThreeBytePrimaryByOffset(p, isCompressible, offset);
126}
127
128uint32_t
129Collation::unassignedPrimaryFromCodePoint(UChar32 c) {
130    // Create a gap before U+0000. Use c=-1 for [first unassigned].
131    ++c;
132    // Fourth byte: 18 values, every 14th byte value (gap of 13).
133    uint32_t primary = 2 + (c % 18) * 14;
134    c /= 18;
135    // Third byte: 254 values.
136    primary |= (2 + (c % 254)) << 8;
137    c /= 254;
138    // Second byte: 251 values 04..FE excluding the primary compression bytes.
139    primary |= (4 + (c % 251)) << 16;
140    // One lead byte covers all code points (c < 0x1182B4 = 1*251*254*18).
141    return primary | (UNASSIGNED_IMPLICIT_BYTE << 24);
142}
143
144U_NAMESPACE_END
145
146#endif  // !UCONFIG_NO_COLLATION
147