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#include "oox/helper/textinputstream.hxx"
#include <rtl/strbuf.hxx>
#include <rtl/ustrbuf.hxx>
#include "oox/helper/binaryinputstream.hxx"

using ::rtl::OStringBuffer;
using ::rtl::OStringToOUString;
using ::rtl::OUString;
using ::rtl::OUStringBuffer;

namespace oox {

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

namespace {

/** Reads a text line from stream. First, tries to skip the second character of
    a two-character line end sequence. Returns the new line-end character. */
template< typename BufferType, typename CharType, typename StreamDataType >
sal_Unicode lclReadLine( BufferType& orBuffer, BinaryInputStream& rInStrm, sal_Unicode cLastEolChar )
{
    // try to skip LF following CR, or CR following LF
    if( !rInStrm.isEof() && (cLastEolChar != 0) )
    {
        CharType cChar = static_cast< CharType >( rInStrm.readValue< StreamDataType >() );
        // return on EOF after line-end
        if( rInStrm.isEof() )
            return 0;
        // return on sequence of equal line-end characters
        bool bIsEolChar = (cChar == 10) || (cChar == 13);
        if( bIsEolChar && (cChar == cLastEolChar) )
            return cChar;
        // append the character, if it is not the other line-end charcter
        if( !bIsEolChar )
            orBuffer.append( cChar );
    }

    // read chars until EOF or line end character (LF or CR)
    while( true )
    {
        CharType cChar = static_cast< CharType >( rInStrm.readValue< StreamDataType >() );
        if( rInStrm.isEof() )
            return 0;
        if( (cChar == 10) || (cChar == 13) )
            return cChar;
        orBuffer.append( cChar );
    }
}

} // namespace

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

TextInputStream::TextInputStream( BinaryInputStream& rInStrm, rtl_TextEncoding eTextEnc ) :
    mrInStrm( rInStrm ),
    meTextEnc( eTextEnc ),
    mcLastEolChar( 0 )
{
}

bool TextInputStream::isEof() const
{
    // do not return EOF, if last text line missed line-end character (see below)
    return mrInStrm.isEof() && (mcLastEolChar == 0);
}

OUString TextInputStream::readLine()
{
    if( mrInStrm.isEof() )
    {
        mcLastEolChar = 0;
        return OUString();
    }

    OUString aLine;
    if( meTextEnc == RTL_TEXTENCODING_UCS2 )
    {
        // read 16-bit characters for UCS2 encoding
        OUStringBuffer aBuffer;
        mcLastEolChar = lclReadLine< OUStringBuffer, sal_Unicode, sal_uInt16 >( aBuffer, mrInStrm, mcLastEolChar );
        aLine = aBuffer.makeStringAndClear();
    }
    else
    {
        // otherwise, read 8-bit characters and convert according to text encoding
        OStringBuffer aBuffer;
        mcLastEolChar = lclReadLine< OStringBuffer, sal_Char, sal_uInt8 >( aBuffer, mrInStrm, mcLastEolChar );
        aLine = OStringToOUString( aBuffer.makeStringAndClear(), meTextEnc );
    }

    // if last line is not empty but line-end character is missing, do not return EOF
    if( mrInStrm.isEof() && (aLine.getLength() > 0) )
        mcLastEolChar = 10;

    return aLine;
}

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

} // namespace oox