path: root/src/mongo/shell/linenoise_utf8.cpp

// linenoise_utf8.cpp
/*
 *    Copyright 2012 10gen Inc.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */

#include "mongo/shell/linenoise_utf8.h"

#ifdef _WIN32
#include <io.h>
#include "mongo/platform/windows_basic.h"
#include "mongo/util/text.h"
#else
#include <unistd.h>
#endif

namespace linenoise_utf8 {

/**
 * Convert a null terminated UTF-8 string from UTF-8 and store it in a UChar32 destination buffer
 * Always null terminates the destination string if at least one character position is available
 * Errors in the UTF-8 encoding will be handled in two ways: the erroneous characters will be
 * converted to the Unicode error character U+FFFD and flag bits will be set in the conversionErrorCode
 * int.
 * 
 * @param uchar32output                 Destination UChar32 buffer
 * @param utf8input                     Source UTF-8 string
 * @param outputBufferSizeInCharacters  Destination buffer size in characters
 * @param outputUnicodeCharacterCount   Number of UChar32 characters placed in output buffer
 * @param conversionErrorCode           Flag bits from enum BadUTF8, or zero if no error
 */
void copyString8to32(
        UChar32* uchar32output,
        const UChar8* utf8input,
        size_t outputBufferSizeInCharacters,
        size_t & outputUnicodeCharacterCount,
        int & conversionErrorCode ) {
    conversionErrorCode = BadUTF8_no_error;
    if ( outputBufferSizeInCharacters == 0 ) {
        outputUnicodeCharacterCount = 0;
        return;
    }
    static const UChar32 errorCharacter = 0xFFFD;
    const UChar8* pIn = utf8input;
    UChar32* pOut = uchar32output;
    UChar32 uchar32;
    int reducedBufferSize = outputBufferSizeInCharacters - 1;
    while ( *pIn && ( pOut - uchar32output ) < reducedBufferSize ) {

        // default to error character so we don't set this in 18 places below
        uchar32 = errorCharacter;

        if ( pIn[0] <= 0x7F ) {         // 0x00000000 to 0x0000007F
            uchar32 = pIn[0];
            pIn += 1;
        }
        else if ( pIn[0] <= 0xDF ) {    // 0x00000080 to 0x000007FF
            if ( ( pIn[0] >= 0xC2 ) && ( pIn[1] >= 0x80 ) && ( pIn[1] <= 0xBF ) ) {
                uchar32 = ( ( pIn[0] & 0x1F ) << 6 ) | ( pIn[1] & 0x3F );
                pIn += 2;
            }
            else {
                conversionErrorCode |= BadUTF8_invalid_byte;
                pIn += 1;
            }
        }
        else if ( pIn[0] == 0xE0 ) {    // 0x00000800 to 0x00000FFF
            if ( ( pIn[1] >= 0xA0 ) && ( pIn[1] <= 0xBF ) ) {
                if ( ( pIn[2] >= 0x80 ) && ( pIn[2] <= 0xBF ) ) {
                    uchar32 = ( ( pIn[1] & 0x3F ) << 6 ) | ( pIn[2] & 0x3F );
                    pIn += 3;
                }
                else {
                    conversionErrorCode |= BadUTF8_invalid_byte;
                    pIn += 2;
                }
            }
            else {
                conversionErrorCode |= BadUTF8_invalid_byte;
                pIn += 1;
            }
        }
        else if ( pIn[0] <= 0xEC ) {    // 0x00001000 to 0x0000CFFF
            if ( ( pIn[1] >= 0x80 ) && ( pIn[1] <= 0xBF ) ) {
                if ( ( pIn[2] >= 0x80 ) && ( pIn[2] <= 0xBF ) ) {
                    uchar32 = ( ( pIn[0] & 0x0F ) << 12 ) | ( ( pIn[1] & 0x3F ) << 6 ) | ( pIn[2] & 0x3F );
                    pIn += 3;
                }
                else {
                    conversionErrorCode |= BadUTF8_invalid_byte;
                    pIn += 2;
                }
            }
            else {
                conversionErrorCode |= BadUTF8_invalid_byte;
                pIn += 1;
            }
        }
        else if ( pIn[0] == 0xED ) {    // 0x0000D000 to 0x0000D7FF
            if ( ( pIn[1] >= 0x80 ) && ( pIn[1] <= 0x9F ) ) {
                if ( ( pIn[2] >= 0x80 ) && ( pIn[2] <= 0xBF ) ) {
                    uchar32 = ( 0x0D << 12 ) | ( ( pIn[1] & 0x3F ) << 6 ) | ( pIn[2] & 0x3F );
                    pIn += 3;
                }
                else {
                    conversionErrorCode |= BadUTF8_invalid_byte;
                    pIn += 2;
                }
            }
            //                          // 0x0000D800 to 0x0000DFFF -- illegal surrogate value
            else if ( ( pIn[1] >= 0x80 ) && ( pIn[1] <= 0xBF ) ) {
                if ( ( pIn[2] >= 0x80 ) && ( pIn[2] <= 0xBF ) ) {
                    conversionErrorCode |= BadUTF8_surrogate;
                    pIn += 3;
                }
                else {
                    conversionErrorCode |= BadUTF8_invalid_byte;
                    pIn += 2;
                }
            }
            else {
                conversionErrorCode |= BadUTF8_invalid_byte;
                pIn += 1;
            }
        }
        else if ( pIn[0] <= 0xEF ) {    // 0x0000E000 to 0x0000FFFF
            if ( ( pIn[1] >= 0x80 ) && ( pIn[1] <= 0xBF ) ) {
                if ( ( pIn[2] >= 0x80 ) && ( pIn[2] <= 0xBF ) ) {
                    uchar32 = ( ( pIn[0] & 0x0F ) << 12 ) | ( ( pIn[1] & 0x3F ) << 6 ) | ( pIn[2] & 0x3F );
                    pIn += 3;
                }
                else {
                    conversionErrorCode |= BadUTF8_invalid_byte;
                    pIn += 2;
                }
            }
            else {
                conversionErrorCode |= BadUTF8_invalid_byte;
                pIn += 1;
            }
        }
        else if ( pIn[0] == 0xF0 ) {    // 0x00010000 to 0x0003FFFF
            if ( ( pIn[1] >= 0x90 ) && ( pIn[1] <= 0xBF ) ) {
                if ( ( pIn[2] >= 0x80 ) && ( pIn[2] <= 0xBF ) ) {
                    if ( ( pIn[3] >= 0x80 ) && ( pIn[3] <= 0xBF ) ) {
                        uchar32 = ( ( pIn[1] & 0x3F ) << 12 ) | ( ( pIn[2] & 0x3F ) << 6 ) | ( pIn[3] & 0x3F );
                        pIn += 4;
                    }
                    else {
                        conversionErrorCode |= BadUTF8_invalid_byte;
                        pIn += 3;
                    }
                }
                else {
                    conversionErrorCode |= BadUTF8_invalid_byte;
                    pIn += 2;
                }
            }
            else {
                conversionErrorCode |= BadUTF8_invalid_byte;
                pIn += 1;
            }
        }
        else if ( pIn[0] <= 0xF4 ) {    // 0x00040000 to 0x0010FFFF
            if ( ( pIn[1] >= 0x80 ) && ( pIn[1] <= 0xBF ) ) {
                if ( ( pIn[2] >= 0x80 ) && ( pIn[2] <= 0xBF ) ) {
                    if ( ( pIn[3] >= 0x80 ) && ( pIn[3] <= 0xBF ) ) {
                        uchar32 = ( ( pIn[0] & 0x07 ) << 18 ) | ( ( pIn[1] & 0x3F ) << 12 ) | ( ( pIn[2] & 0x3F ) << 6 ) | ( pIn[3] & 0x3F );
                        pIn += 4;
                    }
                    else {
                        conversionErrorCode |= BadUTF8_invalid_byte;
                        pIn += 3;
                    }
                }
                else {
                    conversionErrorCode |= BadUTF8_invalid_byte;
                    pIn += 2;
                }
            }
            else {
                conversionErrorCode |= BadUTF8_invalid_byte;
                pIn += 1;
            }
        }
        else {
            conversionErrorCode |= BadUTF8_invalid_byte;
            pIn += 1;
        }
        if ( uchar32 != 0xFEFF ) {      // do not store Byte Order Mark
            *pOut++ = uchar32;
        }
    }
    *pOut = 0;
    outputUnicodeCharacterCount = pOut - uchar32output;
}

/**
 * Copy a null terminated UChar32 string to a UChar32 destination buffer
 * Always null terminates the destination string if at least one character position is available
 * 
 * @param dest32                    Destination UChar32 buffer
 * @param source32                  Source UChar32 string
 * @param destLengthInCharacters    Destination buffer length in characters
 */
void copyString32( UChar32* dest32, const UChar32* source32, size_t destLengthInCharacters ) {
    if ( destLengthInCharacters ) {
        while ( *source32 && --destLengthInCharacters > 0 ) {
            *dest32++ = *source32++;
        }
        *dest32 = 0;
    }
}

/**
 * Convert a specified number of UChar32 characters from a possibly null terminated UChar32 string to UTF-8
 * and store it in a UChar8 destination buffer
 * Always null terminates the destination string if at least one character position is available
 * 
 * @param dest8                     Destination UChar8 buffer
 * @param source32                  Source UChar32 string
 * @param outputBufferSizeInBytes   Destination buffer size in bytes
 * @param charCount                 Maximum number of UChar32 characters to process
 * @return                          Count of bytes written to output buffer, not including null terminator
 */
size_t copyString32to8counted( UChar8* dest8, const UChar32* source32, size_t outputBufferSizeInBytes, size_t charCount ) {
    size_t outputUTF8ByteCount = 0;
    if ( outputBufferSizeInBytes ) {
        size_t reducedBufferSize = outputBufferSizeInBytes - 4;
        while ( charCount-- && *source32 && outputUTF8ByteCount < reducedBufferSize ) {
            UChar32 c = *source32++;
            if ( c <= 0x7F ) {
                *dest8++ = c;
                outputUTF8ByteCount += 1;
            }
            else if ( c <= 0x7FF ) {
                *dest8++ = 0xC0 | ( c >> 6 );
                *dest8++ = 0x80 | ( 0x3F & c );
                outputUTF8ByteCount += 2;
            }
            else if ( c <= 0xFFFF ) {
                *dest8++ = 0xE0 | ( c >> 12 );
                *dest8++ = 0x80 | ( 0x3F & ( c >> 6) );
                *dest8++ = 0x80 | ( 0x3F & c );
                outputUTF8ByteCount += 3;
            }
            else if ( c <= 0x1FFFFF ) {
                *dest8++ = 0xF0 | ( c >> 18 );
                *dest8++ = 0x80 | ( 0x3F & ( c >> 12) );
                *dest8++ = 0x80 | ( 0x3F & ( c >> 6) );
                *dest8++ = 0x80 | ( 0x3F & c );
                outputUTF8ByteCount += 4;
            }
        }
        *dest8 = 0;
    }
    return outputUTF8ByteCount;
}

/**
 * Convert a null terminated UChar32 string to UTF-8 and store it in a UChar8 destination buffer
 * Always null terminates the destination string if at least one character position is available
 * 
 * @param dest8                     Destination UChar8 buffer
 * @param source32                  Source UChar32 string
 * @param outputBufferSizeInBytes   Destination buffer size in bytes
 * @return                          Count of bytes written to output buffer, not including null terminator
 */
size_t copyString32to8( UChar8* dest8, const UChar32* source32, size_t outputBufferSizeInBytes ) {
    return copyString32to8counted( dest8, source32, outputBufferSizeInBytes, 0x7FFFFFFF );
}

/**
 * Count characters (i.e. Unicode code points, array elements) in a null terminated UChar32 string
 * 
 * @param str32     Source UChar32 string
 * @return          String length in characters
 */
size_t strlen32( const UChar32* str32 ) {
    size_t length = 0;
    while ( *str32++ ) {
        ++length;
    }
    return length;
}

/**
 * Compare two UChar32 null-terminated strings with length parameter
 *
 * @param first32   First string to compare
 * @param second32  Second string to compare
 * @param length    Maximum number of characters to compare
 * @return          Negative if first < second, positive if first > second, zero if equal
 */
int strncmp32( UChar32* first32, UChar32* second32, size_t length ) {
    while ( length-- ) {
        if ( *first32 == 0 || *first32 != *second32 ) {
            return *first32 - *second32;
        }
        ++first32;
        ++second32;
    }
    return 0;
}

/**
 * Internally convert an array of UChar32 characters of specified length to UTF-8 and write it to fileHandle
 *
 * @param fileHandle                File handle to write to
 * @param string32                  Source UChar32 characters, may not be null terminated
 * @param sourceLengthInCharacters  Number of source characters to convert and write
 * @return                          Number of bytes written, -1 on error
 */
int write32( int fileHandle, const UChar32* string32, unsigned int sourceLengthInCharacters ) {
    size_t tempBufferBytes = 4 * sourceLengthInCharacters + 1;
    boost::scoped_array<char> tempCharString( new char[ tempBufferBytes ] );
    size_t count = copyString32to8counted( reinterpret_cast<UChar8*>( tempCharString.get() ),
                                           string32,
                                           tempBufferBytes,
                                           sourceLengthInCharacters );
#if defined(_WIN32)
    if ( _isatty( fileHandle ) ) {
        bool success = mongo::writeUtf8ToWindowsConsole( tempCharString.get(), count );
        if ( ! success ) {
            return -1;
        }
        return count;
    }
    else {
        return _write( fileHandle, tempCharString.get(), count );
    }
#else
    return write( fileHandle, tempCharString.get(), count );
#endif
}

} // namespace linenoise_utf8