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// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
*******************************************************************************
* Copyright (C) 2010-2014, International Business Machines
* Corporation and others. All Rights Reserved.
*******************************************************************************
* collation.cpp
*
* created on: 2010oct27
* created by: Markus W. Scherer
*/
#include "unicode/utypes.h"
#if !UCONFIG_NO_COLLATION
#include "collation.h"
#include "uassert.h"
U_NAMESPACE_BEGIN
uint32_t
Collation::incTwoBytePrimaryByOffset(uint32_t basePrimary, UBool isCompressible, int32_t offset) {
// Extract the second byte, minus the minimum byte value,
// plus the offset, modulo the number of usable byte values, plus the minimum.
// Reserve the PRIMARY_COMPRESSION_LOW_BYTE and high byte if necessary.
uint32_t primary;
if(isCompressible) {
offset += ((int32_t)(basePrimary >> 16) & 0xff) - 4;
primary = (uint32_t)((offset % 251) + 4) << 16;
offset /= 251;
} else {
offset += ((int32_t)(basePrimary >> 16) & 0xff) - 2;
primary = (uint32_t)((offset % 254) + 2) << 16;
offset /= 254;
}
// First byte, assume no further overflow.
return primary | ((basePrimary & 0xff000000) + (uint32_t)(offset << 24));
}
uint32_t
Collation::incThreeBytePrimaryByOffset(uint32_t basePrimary, UBool isCompressible, int32_t offset) {
// Extract the third byte, minus the minimum byte value,
// plus the offset, modulo the number of usable byte values, plus the minimum.
offset += ((int32_t)(basePrimary >> 8) & 0xff) - 2;
uint32_t primary = (uint32_t)((offset % 254) + 2) << 8;
offset /= 254;
// Same with the second byte,
// but reserve the PRIMARY_COMPRESSION_LOW_BYTE and high byte if necessary.
if(isCompressible) {
offset += ((int32_t)(basePrimary >> 16) & 0xff) - 4;
primary |= (uint32_t)((offset % 251) + 4) << 16;
offset /= 251;
} else {
offset += ((int32_t)(basePrimary >> 16) & 0xff) - 2;
primary |= (uint32_t)((offset % 254) + 2) << 16;
offset /= 254;
}
// First byte, assume no further overflow.
return primary | ((basePrimary & 0xff000000) + (uint32_t)(offset << 24));
}
uint32_t
Collation::decTwoBytePrimaryByOneStep(uint32_t basePrimary, UBool isCompressible, int32_t step) {
// Extract the second byte, minus the minimum byte value,
// minus the step, modulo the number of usable byte values, plus the minimum.
// Reserve the PRIMARY_COMPRESSION_LOW_BYTE and high byte if necessary.
// Assume no further underflow for the first byte.
U_ASSERT(0 < step && step <= 0x7f);
int32_t byte2 = ((int32_t)(basePrimary >> 16) & 0xff) - step;
if(isCompressible) {
if(byte2 < 4) {
byte2 += 251;
basePrimary -= 0x1000000;
}
} else {
if(byte2 < 2) {
byte2 += 254;
basePrimary -= 0x1000000;
}
}
return (basePrimary & 0xff000000) | ((uint32_t)byte2 << 16);
}
uint32_t
Collation::decThreeBytePrimaryByOneStep(uint32_t basePrimary, UBool isCompressible, int32_t step) {
// Extract the third byte, minus the minimum byte value,
// minus the step, modulo the number of usable byte values, plus the minimum.
U_ASSERT(0 < step && step <= 0x7f);
int32_t byte3 = ((int32_t)(basePrimary >> 8) & 0xff) - step;
if(byte3 >= 2) {
return (basePrimary & 0xffff0000) | ((uint32_t)byte3 << 8);
}
byte3 += 254;
// Same with the second byte,
// but reserve the PRIMARY_COMPRESSION_LOW_BYTE and high byte if necessary.
int32_t byte2 = ((int32_t)(basePrimary >> 16) & 0xff) - 1;
if(isCompressible) {
if(byte2 < 4) {
byte2 = 0xfe;
basePrimary -= 0x1000000;
}
} else {
if(byte2 < 2) {
byte2 = 0xff;
basePrimary -= 0x1000000;
}
}
// First byte, assume no further underflow.
return (basePrimary & 0xff000000) | ((uint32_t)byte2 << 16) | ((uint32_t)byte3 << 8);
}
uint32_t
Collation::getThreeBytePrimaryForOffsetData(UChar32 c, int64_t dataCE) {
uint32_t p = (uint32_t)(dataCE >> 32); // three-byte primary pppppp00
int32_t lower32 = (int32_t)dataCE; // base code point b & step s: bbbbbbss (bit 7: isCompressible)
int32_t offset = (c - (lower32 >> 8)) * (lower32 & 0x7f); // delta * increment
UBool isCompressible = (lower32 & 0x80) != 0;
return Collation::incThreeBytePrimaryByOffset(p, isCompressible, offset);
}
uint32_t
Collation::unassignedPrimaryFromCodePoint(UChar32 c) {
// Create a gap before U+0000. Use c=-1 for [first unassigned].
++c;
// Fourth byte: 18 values, every 14th byte value (gap of 13).
uint32_t primary = 2 + (c % 18) * 14;
c /= 18;
// Third byte: 254 values.
primary |= (2 + (c % 254)) << 8;
c /= 254;
// Second byte: 251 values 04..FE excluding the primary compression bytes.
primary |= (4 + (c % 251)) << 16;
// One lead byte covers all code points (c < 0x1182B4 = 1*251*254*18).
return primary | (UNASSIGNED_IMPLICIT_BYTE << 24);
}
U_NAMESPACE_END
#endif // !UCONFIG_NO_COLLATION
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