// © 2016 and later: Unicode, Inc. and others.

// License & terms of use: http://www.unicode.org/copyright.html

/*

*******************************************************************************

*   Copyright (C) 2010-2012, International Business Machines

*   Corporation and others.  All Rights Reserved.

*******************************************************************************

*   file name:  ucharstriebuilder.h

*   encoding:   UTF-8

*   tab size:   8 (not used)

*   indentation:4

*

*   created on: 2010nov14

*   created by: Markus W. Scherer

*/

#include "unicode/utypes.h"

#include "unicode/ucharstrie.h"

#include "unicode/ucharstriebuilder.h"

#include "unicode/unistr.h"

#include "unicode/ustring.h"

#include "cmemory.h"

#include "uarrsort.h"

#include "uassert.h"

#include "uhash.h"

#include "ustr_imp.h"

U_NAMESPACE_BEGIN

/*

 * Note: This builder implementation stores (string, value) pairs with full copies

 * of the 16-bit-unit sequences, until the UCharsTrie is built.

 * It might(!) take less memory if we collected the data in a temporary, dynamic trie.

 */

class UCharsTrieElement : public UMemory {

public:

    // Use compiler's default constructor, initializes nothing.

    void setTo(const UnicodeString &s, int32_t val, UnicodeString &strings, UErrorCode &errorCode);

    UnicodeString getString(const UnicodeString &strings) const {

        int32_t length=strings[stringOffset];

        return strings.tempSubString(stringOffset+1, length);

    }

    int32_t getStringLength(const UnicodeString &strings) const {

        return strings[stringOffset];

    }

    char16_t charAt(int32_t index, const UnicodeString &strings) const {

        return strings[stringOffset+1+index];

    }

    int32_t getValue() const { return value; }

    int32_t compareStringTo(const UCharsTrieElement &o, const UnicodeString &strings) const;

private:

    // The first strings unit contains the string length.

    // (Compared with a stringLength field here, this saves 2 bytes per string.)

    int32_t stringOffset;

    int32_t value;

};

void

UCharsTrieElement::setTo(const UnicodeString &s, int32_t val,

                         UnicodeString &strings, UErrorCode &errorCode) {

    if(U_FAILURE(errorCode)) {

        return;

    }

    int32_t length=s.length();

    if(length>0xffff) {

        // Too long: We store the length in 1 unit.

        errorCode=U_INDEX_OUTOFBOUNDS_ERROR;

        return;

    }

    stringOffset=strings.length();

    strings.append(static_cast<char16_t>(length));

    value=val;

    strings.append(s);

}

int32_t

UCharsTrieElement::compareStringTo(const UCharsTrieElement &other, const UnicodeString &strings) const {

    return getString(strings).compare(other.getString(strings));

}

UCharsTrieBuilder::UCharsTrieBuilder(UErrorCode & /*errorCode*/)

        : elements(nullptr), elementsCapacity(0), elementsLength(0),

          uchars(nullptr), ucharsCapacity(0), ucharsLength(0) {}

UCharsTrieBuilder::~UCharsTrieBuilder() {

    delete[] elements;

    uprv_free(uchars);

}

UCharsTrieBuilder &

UCharsTrieBuilder::add(const UnicodeString &s, int32_t value, UErrorCode &errorCode) {

    if(U_FAILURE(errorCode)) {

        return *this;

    }

    if(ucharsLength>0) {

        // Cannot add elements after building.

        errorCode=U_NO_WRITE_PERMISSION;

        return *this;

    }

    if(elementsLength==elementsCapacity) {

        int32_t newCapacity;

        if(elementsCapacity==0) {

            newCapacity=1024;

        } else {

            newCapacity=4*elementsCapacity;

        }

        UCharsTrieElement *newElements=new UCharsTrieElement[newCapacity];

        if(newElements==nullptr) {

            errorCode=U_MEMORY_ALLOCATION_ERROR;

            return *this;

        }

        if(elementsLength>0) {

            uprv_memcpy(newElements, elements, (size_t)elementsLength*sizeof(UCharsTrieElement));

        }

        delete[] elements;

        elements=newElements;

        elementsCapacity=newCapacity;

    }

    elements[elementsLength++].setTo(s, value, strings, errorCode);

    if(U_SUCCESS(errorCode) && strings.isBogus()) {

        errorCode=U_MEMORY_ALLOCATION_ERROR;

    }

    return *this;

}

U_CDECL_BEGIN

static int32_t U_CALLCONV

compareElementStrings(const void *context, const void *left, const void *right) {

    const UnicodeString *strings=static_cast<const UnicodeString *>(context);

    const UCharsTrieElement *leftElement=static_cast<const UCharsTrieElement *>(left);

    const UCharsTrieElement *rightElement=static_cast<const UCharsTrieElement *>(right);

    return leftElement->compareStringTo(*rightElement, *strings);

}

U_CDECL_END

UCharsTrie *

UCharsTrieBuilder::build(UStringTrieBuildOption buildOption, UErrorCode &errorCode) {

    buildUChars(buildOption, errorCode);

    UCharsTrie *newTrie=nullptr;

    if(U_SUCCESS(errorCode)) {

        newTrie=new UCharsTrie(uchars, uchars+(ucharsCapacity-ucharsLength));

        if(newTrie==nullptr) {

            errorCode=U_MEMORY_ALLOCATION_ERROR;

        } else {

            uchars=nullptr;  // The new trie now owns the array.

            ucharsCapacity=0;

        }

    }

    return newTrie;

}

UnicodeString &

UCharsTrieBuilder::buildUnicodeString(UStringTrieBuildOption buildOption, UnicodeString &result,

                                      UErrorCode &errorCode) {

    buildUChars(buildOption, errorCode);

    if(U_SUCCESS(errorCode)) {

        result.setTo(false, uchars+(ucharsCapacity-ucharsLength), ucharsLength);

    }

    return result;

}

void

UCharsTrieBuilder::buildUChars(UStringTrieBuildOption buildOption, UErrorCode &errorCode) {

    if(U_FAILURE(errorCode)) {

        return;

    }

    if(uchars!=nullptr && ucharsLength>0) {

        // Already built.

        return;

    }

    if(ucharsLength==0) {

        if(elementsLength==0) {

            errorCode=U_INDEX_OUTOFBOUNDS_ERROR;

            return;

        }

        if(strings.isBogus()) {

            errorCode=U_MEMORY_ALLOCATION_ERROR;

            return;

        }

        uprv_sortArray(elements, elementsLength, static_cast<int32_t>(sizeof(UCharsTrieElement)),

                      compareElementStrings, &strings,

                      false,  // need not be a stable sort

                      &errorCode);

        if(U_FAILURE(errorCode)) {

            return;

        }

        // Duplicate strings are not allowed.

        UnicodeString prev=elements[0].getString(strings);

        for(int32_t i=1; i<elementsLength; ++i) {

            UnicodeString current=elements[i].getString(strings);

            if(prev==current) {

                errorCode=U_ILLEGAL_ARGUMENT_ERROR;

                return;

            }

            prev.fastCopyFrom(current);

        }

    }

    // Create and char16_t-serialize the trie for the elements.

    ucharsLength=0;

    int32_t capacity=strings.length();

    if(capacity<1024) {

        capacity=1024;

    }

    if(ucharsCapacity<capacity) {

        uprv_free(uchars);

        uchars=static_cast<char16_t *>(uprv_malloc(capacity*2));

        if(uchars==nullptr) {

            errorCode=U_MEMORY_ALLOCATION_ERROR;

            ucharsCapacity=0;

            return;

        }

        ucharsCapacity=capacity;

    }

    StringTrieBuilder::build(buildOption, elementsLength, errorCode);

    if(uchars==nullptr) {

        errorCode=U_MEMORY_ALLOCATION_ERROR;

    }

}

int32_t

UCharsTrieBuilder::getElementStringLength(int32_t i) const {

    return elements[i].getStringLength(strings);

}

char16_t

UCharsTrieBuilder::getElementUnit(int32_t i, int32_t unitIndex) const {

    return elements[i].charAt(unitIndex, strings);

}

int32_t

UCharsTrieBuilder::getElementValue(int32_t i) const {

    return elements[i].getValue();

}

int32_t

UCharsTrieBuilder::getLimitOfLinearMatch(int32_t first, int32_t last, int32_t unitIndex) const {

    const UCharsTrieElement &firstElement=elements[first];

    const UCharsTrieElement &lastElement=elements[last];

    int32_t minStringLength=firstElement.getStringLength(strings);

    while(++unitIndex<minStringLength &&

            firstElement.charAt(unitIndex, strings)==

            lastElement.charAt(unitIndex, strings)) {}

    return unitIndex;

}

int32_t

UCharsTrieBuilder::countElementUnits(int32_t start, int32_t limit, int32_t unitIndex) const {

    int32_t length=0;  // Number of different units at unitIndex.

    int32_t i=start;

    do {

        char16_t unit=elements[i++].charAt(unitIndex, strings);

        while(i<limit && unit==elements[i].charAt(unitIndex, strings)) {

            ++i;

        }

        ++length;

    } while(i<limit);

    return length;

}

int32_t

UCharsTrieBuilder::skipElementsBySomeUnits(int32_t i, int32_t unitIndex, int32_t count) const {

    do {

        char16_t unit=elements[i++].charAt(unitIndex, strings);

        while(unit==elements[i].charAt(unitIndex, strings)) {

            ++i;

        }

    } while(--count>0);

    return i;

}

int32_t

UCharsTrieBuilder::indexOfElementWithNextUnit(int32_t i, int32_t unitIndex, char16_t unit) const {

    while(unit==elements[i].charAt(unitIndex, strings)) {

        ++i;

    }

    return i;

}

UCharsTrieBuilder::UCTLinearMatchNode::UCTLinearMatchNode(const char16_t *units, int32_t len, Node *nextNode)

        : LinearMatchNode(len, nextNode), s(units) {

    hash=hash*37u+ustr_hashUCharsN(units, len);

}

bool

UCharsTrieBuilder::UCTLinearMatchNode::operator==(const Node &other) const {

    if(this==&other) {

        return true;

    }

    if(!LinearMatchNode::operator==(other)) {

        return false;

    }

    const UCTLinearMatchNode &o=static_cast<const UCTLinearMatchNode &>(other);

    return 0==u_memcmp(s, o.s, length);

}

void

UCharsTrieBuilder::UCTLinearMatchNode::write(StringTrieBuilder &builder) {

    UCharsTrieBuilder &b=(UCharsTrieBuilder &)builder;

    next->write(builder);

    b.write(s, length);

    offset=b.writeValueAndType(hasValue, value, b.getMinLinearMatch()+length-1);

}

StringTrieBuilder::Node *

UCharsTrieBuilder::createLinearMatchNode(int32_t i, int32_t unitIndex, int32_t length,

                                         Node *nextNode) const {

    return new UCTLinearMatchNode(

            elements[i].getString(strings).getBuffer()+unitIndex,

            length,

            nextNode);

}

UBool

UCharsTrieBuilder::ensureCapacity(int32_t length) {

    if(uchars==nullptr) {

        return false;  // previous memory allocation had failed

    }

    if(length>ucharsCapacity) {

        int32_t newCapacity=ucharsCapacity;

        do {

            newCapacity*=2;

        } while(newCapacity<=length);

        char16_t *newUChars=static_cast<char16_t *>(uprv_malloc(newCapacity*2));

        if(newUChars==nullptr) {

            // unable to allocate memory

            uprv_free(uchars);

            uchars=nullptr;

            ucharsCapacity=0;

            return false;

        }

        u_memcpy(newUChars+(newCapacity-ucharsLength),

                 uchars+(ucharsCapacity-ucharsLength), ucharsLength);

        uprv_free(uchars);

        uchars=newUChars;

        ucharsCapacity=newCapacity;

    }

    return true;

}

int32_t

UCharsTrieBuilder::write(int32_t unit) {

    int32_t newLength=ucharsLength+1;

    if(ensureCapacity(newLength)) {

        ucharsLength=newLength;

        uchars[ucharsCapacity - ucharsLength] = static_cast<char16_t>(unit);

    }

    return ucharsLength;

}

int32_t

UCharsTrieBuilder::write(const char16_t *s, int32_t length) {

    int32_t newLength=ucharsLength+length;

    if(ensureCapacity(newLength)) {

        ucharsLength=newLength;

        u_memcpy(uchars+(ucharsCapacity-ucharsLength), s, length);

    }

    return ucharsLength;

}

int32_t

UCharsTrieBuilder::writeElementUnits(int32_t i, int32_t unitIndex, int32_t length) {

    return write(elements[i].getString(strings).getBuffer()+unitIndex, length);

}

int32_t

UCharsTrieBuilder::writeValueAndFinal(int32_t i, UBool isFinal) {

    if(0<=i && i<=UCharsTrie::kMaxOneUnitValue) {

        return write(i|(isFinal<<15));

    }

    char16_t intUnits[3];

    int32_t length;

    if(i<0 || i>UCharsTrie::kMaxTwoUnitValue) {

        intUnits[0] = static_cast<char16_t>(UCharsTrie::kThreeUnitValueLead);

        intUnits[1] = static_cast<char16_t>(static_cast<uint32_t>(i) >> 16);

        intUnits[2] = static_cast<char16_t>(i);

        length=3;

    // } else if(i<=UCharsTrie::kMaxOneUnitValue) {

    //     intUnits[0]=(char16_t)(i);

    //     length=1;

    } else {

        intUnits[0] = static_cast<char16_t>(UCharsTrie::kMinTwoUnitValueLead + (i >> 16));

        intUnits[1] = static_cast<char16_t>(i);

        length=2;

    }

    intUnits[0] = static_cast<char16_t>(intUnits[0] | (isFinal << 15));

    return write(intUnits, length);

}

int32_t

UCharsTrieBuilder::writeValueAndType(UBool hasValue, int32_t value, int32_t node) {

    if(!hasValue) {

        return write(node);

    }

    char16_t intUnits[3];

    int32_t length;

    if(value<0 || value>UCharsTrie::kMaxTwoUnitNodeValue) {

        intUnits[0] = static_cast<char16_t>(UCharsTrie::kThreeUnitNodeValueLead);

        intUnits[1] = static_cast<char16_t>(static_cast<uint32_t>(value) >> 16);

        intUnits[2] = static_cast<char16_t>(value);

        length=3;

    } else if(value<=UCharsTrie::kMaxOneUnitNodeValue) {

        intUnits[0] = static_cast<char16_t>((value + 1) << 6);

        length=1;

    } else {

        intUnits[0] = static_cast<char16_t>(UCharsTrie::kMinTwoUnitNodeValueLead + ((value >> 10) & 0x7fc0));

        intUnits[1] = static_cast<char16_t>(value);

        length=2;

    }

    intUnits[0] |= static_cast<char16_t>(node);

    return write(intUnits, length);

}

int32_t

UCharsTrieBuilder::writeDeltaTo(int32_t jumpTarget) {

    int32_t i=ucharsLength-jumpTarget;

    U_ASSERT(i>=0);

    if(i<=UCharsTrie::kMaxOneUnitDelta) {

        return write(i);

    }

    char16_t intUnits[3];

    int32_t length;

    if(i<=UCharsTrie::kMaxTwoUnitDelta) {

        intUnits[0] = static_cast<char16_t>(UCharsTrie::kMinTwoUnitDeltaLead + (i >> 16));

        length=1;

    } else {

        intUnits[0] = static_cast<char16_t>(UCharsTrie::kThreeUnitDeltaLead);

        intUnits[1] = static_cast<char16_t>(i >> 16);

        length=2;

    }

    intUnits[length++] = static_cast<char16_t>(i);

    return write(intUnits, length);

}

U_NAMESPACE_END