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

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

/*

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

*

*   Copyright (C) 1999-2014, International Business Machines

*   Corporation and others.  All Rights Reserved.

*

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

*   file name:  unistr_cnv.cpp

*   encoding:   UTF-8

*   tab size:   8 (not used)

*   indentation:2

*

*   created on: 2004aug19

*   created by: Markus W. Scherer

*

*   Character conversion functions moved here from unistr.cpp

*/

#include "unicode/utypes.h"

#if !UCONFIG_NO_CONVERSION

#include "unicode/putil.h"

#include "cstring.h"

#include "cmemory.h"

#include "unicode/ustring.h"

#include "unicode/unistr.h"

#include "unicode/ucnv.h"

#include "ucnv_imp.h"

#include "putilimp.h"

#include "ustr_cnv.h"

#include "ustr_imp.h"

U_NAMESPACE_BEGIN

//========================================

// Constructors

//========================================

#if !U_CHARSET_IS_UTF8

UnicodeString::UnicodeString(const char *codepageData) {

    fUnion.fFields.fLengthAndFlags = kShortString;

    if(codepageData != 0) {

        doCodepageCreate(codepageData, (int32_t)uprv_strlen(codepageData), 0);

    }

}

UnicodeString::UnicodeString(const char *codepageData,

                             int32_t dataLength) {

    fUnion.fFields.fLengthAndFlags = kShortString;

    if(codepageData != 0) {

        doCodepageCreate(codepageData, dataLength, 0);

    }

}

// else see unistr.cpp

#endif

UnicodeString::UnicodeString(const char *codepageData,

                             const char *codepage) {

    fUnion.fFields.fLengthAndFlags = kShortString;

    if(codepageData != 0) {

        doCodepageCreate(codepageData, (int32_t)uprv_strlen(codepageData), codepage);

    }

}

UnicodeString::UnicodeString(const char *codepageData,

                             int32_t dataLength,

                             const char *codepage) {

    fUnion.fFields.fLengthAndFlags = kShortString;

    if(codepageData != 0) {

        doCodepageCreate(codepageData, dataLength, codepage);

    }

}

UnicodeString::UnicodeString(const char *src, int32_t srcLength,

                             UConverter *cnv,

                             UErrorCode &errorCode) {

    fUnion.fFields.fLengthAndFlags = kShortString;

    if(U_SUCCESS(errorCode)) {

        // check arguments

        if(src==nullptr) {

            // treat as an empty string, do nothing more

        } else if(srcLength<-1) {

            errorCode=U_ILLEGAL_ARGUMENT_ERROR;

        } else {

            // get input length

            if(srcLength==-1) {

                srcLength=(int32_t)uprv_strlen(src);

            }

            if(srcLength>0) {

                if(cnv!=0) {

                    // use the provided converter

                    ucnv_resetToUnicode(cnv);

                    doCodepageCreate(src, srcLength, cnv, errorCode);

                } else {

                    // use the default converter

                    cnv=u_getDefaultConverter(&errorCode);

                    doCodepageCreate(src, srcLength, cnv, errorCode);

                    u_releaseDefaultConverter(cnv);

                }

            }

        }

        if(U_FAILURE(errorCode)) {

            setToBogus();

        }

    }

}

//========================================

// Codeset conversion

//========================================

#if !U_CHARSET_IS_UTF8

int32_t

UnicodeString::extract(int32_t start,

                       int32_t length,

                       char *target,

                       uint32_t dstSize) const {

    return extract(start, length, target, dstSize, 0);

}

// else see unistr.cpp

#endif

int32_t

UnicodeString::extract(int32_t start,

                       int32_t length,

                       char *target,

                       uint32_t dstSize,

                       const char *codepage) const

{

    // if the arguments are illegal, then do nothing

    if(/*dstSize < 0 || */(dstSize > 0 && target == 0)) {

        return 0;

    }

    // pin the indices to legal values

    pinIndices(start, length);

    // We need to cast dstSize to int32_t for all subsequent code.

    // I don't know why the API was defined with uint32_t but we are stuck with it.

    // Also, dstSize==0xffffffff means "unlimited" but if we use target+dstSize

    // as a limit in some functions, it may wrap around and yield a pointer

    // that compares less-than target.

    int32_t capacity;

    if(dstSize < 0x7fffffff) {

        // Assume that the capacity is real and a limit pointer won't wrap around.

        capacity = (int32_t)dstSize;

    } else {

        // Pin the capacity so that a limit pointer does not wrap around.

        char *targetLimit = (char *)U_MAX_PTR(target);

        // U_MAX_PTR(target) returns a targetLimit that is at most 0x7fffffff

        // greater than target and does not wrap around the top of the address space.

        capacity = (int32_t)(targetLimit - target);

    }

    // create the converter

    UConverter *converter;

    UErrorCode status = U_ZERO_ERROR;

    // just write the NUL if the string length is 0

    if(length == 0) {

        return u_terminateChars(target, capacity, 0, &status);

    }

    // if the codepage is the default, use our cache

    // if it is an empty string, then use the "invariant character" conversion

    if (codepage == 0) {

        const char *defaultName = ucnv_getDefaultName();

        if(UCNV_FAST_IS_UTF8(defaultName)) {

            return toUTF8(start, length, target, capacity);

        }

        converter = u_getDefaultConverter(&status);

    } else if (*codepage == 0) {

        // use the "invariant characters" conversion

        int32_t destLength;

        if(length <= capacity) {

            destLength = length;

        } else {

            destLength = capacity;

        }

        u_UCharsToChars(getArrayStart() + start, target, destLength);

        return u_terminateChars(target, capacity, length, &status);

    } else {

        converter = ucnv_open(codepage, &status);

    }

    length = doExtract(start, length, target, capacity, converter, status);

    // close the converter

    if (codepage == 0) {

        u_releaseDefaultConverter(converter);

    } else {

        ucnv_close(converter);

    }

    return length;

}

int32_t

UnicodeString::extract(char *dest, int32_t destCapacity,

                       UConverter *cnv,

                       UErrorCode &errorCode) const

{

    if(U_FAILURE(errorCode)) {

        return 0;

    }

    if(isBogus() || destCapacity<0 || (destCapacity>0 && dest==0)) {

        errorCode=U_ILLEGAL_ARGUMENT_ERROR;

        return 0;

    }

    // nothing to do?

    if(isEmpty()) {

        return u_terminateChars(dest, destCapacity, 0, &errorCode);

    }

    // get the converter

    UBool isDefaultConverter;

    if(cnv==0) {

        isDefaultConverter=true;

        cnv=u_getDefaultConverter(&errorCode);

        if(U_FAILURE(errorCode)) {

            return 0;

        }

    } else {

        isDefaultConverter=false;

        ucnv_resetFromUnicode(cnv);

    }

    // convert

    int32_t len=doExtract(0, length(), dest, destCapacity, cnv, errorCode);

    // release the converter

    if(isDefaultConverter) {

        u_releaseDefaultConverter(cnv);

    }

    return len;

}

int32_t

UnicodeString::doExtract(int32_t start, int32_t length,

                         char *dest, int32_t destCapacity,

                         UConverter *cnv,

                         UErrorCode &errorCode) const

{

    if(U_FAILURE(errorCode)) {

        if(destCapacity!=0) {

            *dest=0;

        }

        return 0;

    }

    const char16_t *src=getArrayStart()+start, *srcLimit=src+length;

    char *originalDest=dest;

    const char *destLimit;

    if(destCapacity==0) {

        destLimit=dest=0;

    } else if(destCapacity==-1) {

        // Pin the limit to U_MAX_PTR if the "magic" destCapacity is used.

        destLimit=(char*)U_MAX_PTR(dest);

        // for NUL-termination, translate into highest int32_t

        destCapacity=0x7fffffff;

    } else {

        destLimit=dest+destCapacity;

    }

    // perform the conversion

    ucnv_fromUnicode(cnv, &dest, destLimit, &src, srcLimit, 0, true, &errorCode);

    length=(int32_t)(dest-originalDest);

    // if an overflow occurs, then get the preflighting length

    if(errorCode==U_BUFFER_OVERFLOW_ERROR) {

        char buffer[1024];

        destLimit=buffer+sizeof(buffer);

        do {

            dest=buffer;

            errorCode=U_ZERO_ERROR;

            ucnv_fromUnicode(cnv, &dest, destLimit, &src, srcLimit, 0, true, &errorCode);

            length+=(int32_t)(dest-buffer);

        } while(errorCode==U_BUFFER_OVERFLOW_ERROR);

    }

    return u_terminateChars(originalDest, destCapacity, length, &errorCode);

}

void

UnicodeString::doCodepageCreate(const char *codepageData,

                                int32_t dataLength,

                                const char *codepage)

{

    // if there's nothing to convert, do nothing

    if(codepageData == 0 || dataLength == 0 || dataLength < -1) {

        return;

    }

    if(dataLength == -1) {

        dataLength = (int32_t)uprv_strlen(codepageData);

    }

    UErrorCode status = U_ZERO_ERROR;

    // create the converter

    // if the codepage is the default, use our cache

    // if it is an empty string, then use the "invariant character" conversion

    UConverter *converter;

    if (codepage == 0) {

        const char *defaultName = ucnv_getDefaultName();

        if(UCNV_FAST_IS_UTF8(defaultName)) {

            setToUTF8(StringPiece(codepageData, dataLength));

            return;

        }

        converter = u_getDefaultConverter(&status);

    } else if(*codepage == 0) {

        // use the "invariant characters" conversion

        if(cloneArrayIfNeeded(dataLength, dataLength, false)) {

            u_charsToUChars(codepageData, getArrayStart(), dataLength);

            setLength(dataLength);

        } else {

            setToBogus();

        }

        return;

    } else {

        converter = ucnv_open(codepage, &status);

    }

    // if we failed, set the appropriate flags and return

    if(U_FAILURE(status)) {

        setToBogus();

        return;

    }

    // perform the conversion

    doCodepageCreate(codepageData, dataLength, converter, status);

    if(U_FAILURE(status)) {

        setToBogus();

    }

    // close the converter

    if(codepage == 0) {

        u_releaseDefaultConverter(converter);

    } else {

        ucnv_close(converter);

    }

}

void

UnicodeString::doCodepageCreate(const char *codepageData,

                                int32_t dataLength,

                                UConverter *converter,

                                UErrorCode &status)

{

    if(U_FAILURE(status)) {

        return;

    }

    // set up the conversion parameters

    const char *mySource     = codepageData;

    const char *mySourceEnd  = mySource + dataLength;

    char16_t *array, *myTarget;

    // estimate the size needed:

    int32_t arraySize;

    if(dataLength <= US_STACKBUF_SIZE) {

        // try to use the stack buffer

        arraySize = US_STACKBUF_SIZE;

    } else {

        // 1.25 char16_t's per source byte should cover most cases

        arraySize = dataLength + (dataLength >> 2);

    }

    // we do not care about the current contents

    UBool doCopyArray = false;

    for(;;) {

        if(!cloneArrayIfNeeded(arraySize, arraySize, doCopyArray)) {

            setToBogus();

            break;

        }

        // perform the conversion

        array = getArrayStart();

        myTarget = array + length();

        ucnv_toUnicode(converter, &myTarget,  array + getCapacity(),

            &mySource, mySourceEnd, 0, true, &status);

        // update the conversion parameters

        setLength((int32_t)(myTarget - array));

        // allocate more space and copy data, if needed

        if(status == U_BUFFER_OVERFLOW_ERROR) {

            // reset the error code

            status = U_ZERO_ERROR;

            // keep the previous conversion results

            doCopyArray = true;

            // estimate the new size needed, larger than before

            // try 2 char16_t's per remaining source byte

            arraySize = (int32_t)(length() + 2 * (mySourceEnd - mySource));

        } else {

            break;

        }

    }

}

U_NAMESPACE_END

#endif