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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 
 
// Some compilers don't care if constants are defined in the .cpp file. 
// MS Visual C++ does not like it, but gcc requires it. clang does not care. 
#ifndef _MSC_VER 
const uint8_t Collation::LEVEL_SEPARATOR_BYTE; 
const uint8_t Collation::MERGE_SEPARATOR_BYTE; 
const uint32_t Collation::ONLY_TERTIARY_MASK; 
const uint32_t Collation::CASE_AND_TERTIARY_MASK; 
#endif 
 
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