/// <summary>Encode the given crazy code bytes into the given byte stream.</summary>
/// <remarks>Encode the given crazy code bytes into the given byte stream.</remarks>
/// <exception cref="System.IO.IOException"></exception>
private static void WriteCrazyCodes(ByteUtil.ByteStream crazyCodes, ByteUtil.ByteStream
bout)
{
// CRAZY_CODE_2 flags at the end are ignored, so ditch them
TrimExtraCodes(crazyCodes, CRAZY_CODE_2, CRAZY_CODE_2);
if (crazyCodes.GetLength() > 0)
{
// the crazy codes get encoded into 6 bit sequences where each code is 2
// bits (where the first 2 bits in the byte are a common prefix).
byte curByte = CRAZY_CODE_START;
int idx = 0;
for (int i = 0; i < crazyCodes.GetLength(); ++i)
{
byte nextByte = crazyCodes.Get(i);
nextByte <<= ((2 - idx) * 2);
curByte |= nextByte;
++idx;
if (idx == 3)
{
// write current byte and reset
bout.Write(curByte);
curByte = CRAZY_CODE_START;
idx = 0;
}
}
// write last byte
if (idx > 0)
{
bout.Write(curByte);
}
}
// write crazy code suffix (note, we write this even if all the codes are
// trimmed
bout.Write(CRAZY_CODES_SUFFIX);
}
/// <summary>Encodes the given unprintable char codes in the given stream.</summary>
/// <remarks>Encodes the given unprintable char codes in the given stream.</remarks>
/// <exception cref="System.IO.IOException"></exception>
private static void WriteUnprintableCodes(int charOffset, byte[] bytes, ByteUtil.ByteStream
unprintableCodes, GeneralLegacyIndexCodes.ExtraCodesStream extraCodes)
{
// the offset seems to be calculated based on the number of bytes in the
// "extra codes" part of the entry (even if there are no extra codes bytes
// actually written in the final entry).
int unprintCharOffset = charOffset;
if (extraCodes != null)
{
// we need to account for some extra codes which have not been written
// yet. additionally, any unprintable bytes added to the beginning of
// the extra codes are ignored.
unprintCharOffset = extraCodes.GetLength() + (charOffset - extraCodes.GetNumChars
()) - extraCodes.GetUnprintablePrefixLen();
}
// we write a whacky combo of bytes for each unprintable char which
// includes a funky offset and extra char itself
int offset = (UNPRINTABLE_COUNT_START + (UNPRINTABLE_COUNT_MULTIPLIER * unprintCharOffset
)) | UNPRINTABLE_OFFSET_FLAGS;
// write offset as big-endian short
unprintableCodes.Write((offset >> 8) & unchecked ((int)(0xFF)));
unprintableCodes.Write(offset & unchecked ((int)(0xFF)));
unprintableCodes.Write(UNPRINTABLE_MIDFIX);
unprintableCodes.Write(bytes);
}
/// <summary>
/// Trims any bytes in the given range off of the end of the given stream,
/// returning whether or not there are any bytes left in the given stream
/// after trimming.
/// </summary>
/// <remarks>
/// Trims any bytes in the given range off of the end of the given stream,
/// returning whether or not there are any bytes left in the given stream
/// after trimming.
/// </remarks>
/// <exception cref="System.IO.IOException"></exception>
private static bool TrimExtraCodes(ByteUtil.ByteStream extraCodes, byte minTrimCode
, byte maxTrimCode)
{
if (extraCodes == null)
{
return(false);
}
extraCodes.TrimTrailing(minTrimCode, maxTrimCode);
// anything left?
return(extraCodes.GetLength() > 0);
}
/// <summary>
/// Converts an index value for a text column into the entry value (which
/// is based on a variety of nifty codes).
/// </summary>
/// <remarks>
/// Converts an index value for a text column into the entry value (which
/// is based on a variety of nifty codes).
/// </remarks>
/// <exception cref="System.IO.IOException"></exception>
internal virtual void WriteNonNullIndexTextValue(object value, ByteUtil.ByteStream
bout, bool isAscending)
{
// first, convert to string
string str = Column.ToCharSequence(value).ToString();
// all text columns (including memos) are only indexed up to the max
// number of chars in a VARCHAR column
if (str.Length > MAX_TEXT_INDEX_CHAR_LENGTH)
{
str = Sharpen.Runtime.Substring(str, 0, MAX_TEXT_INDEX_CHAR_LENGTH);
}
// record pprevious entry length so we can do any post-processing
// necessary for this entry (handling descending)
int prevLength = bout.GetLength();
// now, convert each character to a "code" of one or more bytes
GeneralLegacyIndexCodes.ExtraCodesStream extraCodes = null;
ByteUtil.ByteStream unprintableCodes = null;
ByteUtil.ByteStream crazyCodes = null;
int charOffset = 0;
for (int i = 0; i < str.Length; ++i)
{
char c = str[i];
GeneralLegacyIndexCodes.CharHandler ch = GetCharHandler(c);
int curCharOffset = charOffset;
byte[] bytes = ch.GetInlineBytes();
if (bytes != null)
{
// write the "inline" codes immediately
bout.Write(bytes);
// only increment the charOffset for chars with inline codes
++charOffset;
}
if (ch.GetEncodingType() == GeneralLegacyIndexCodes.Type.SIMPLE)
{
// common case, skip further code handling
continue;
}
bytes = ch.GetExtraBytes();
byte extraCodeModifier = ch.GetExtraByteModifier();
if ((bytes != null) || (extraCodeModifier != 0))
{
if (extraCodes == null)
{
extraCodes = new GeneralLegacyIndexCodes.ExtraCodesStream(str.Length);
}
// keep track of the extra codes for later
WriteExtraCodes(curCharOffset, bytes, extraCodeModifier, extraCodes);
}
bytes = ch.GetUnprintableBytes();
if (bytes != null)
{
if (unprintableCodes == null)
{
unprintableCodes = new ByteUtil.ByteStream();
}
// keep track of the unprintable codes for later
WriteUnprintableCodes(curCharOffset, bytes, unprintableCodes, extraCodes);
}
byte crazyFlag = ch.GetCrazyFlag();
if (crazyFlag != 0)
{
if (crazyCodes == null)
{
crazyCodes = new ByteUtil.ByteStream();
}
// keep track of the crazy flags for later
crazyCodes.Write(crazyFlag);
}
}
// write end text flag
bout.Write(END_TEXT);
bool hasExtraCodes = TrimExtraCodes(extraCodes, unchecked ((byte)0), INTERNATIONAL_EXTRA_PLACEHOLDER
);
bool hasUnprintableCodes = (unprintableCodes != null);
bool hasCrazyCodes = (crazyCodes != null);
if (hasExtraCodes || hasUnprintableCodes || hasCrazyCodes)
{
// we write all the international extra bytes first
if (hasExtraCodes)
{
extraCodes.WriteTo(bout);
}
if (hasCrazyCodes || hasUnprintableCodes)
{
// write 2 more end flags
bout.Write(END_TEXT);
bout.Write(END_TEXT);
// next come the crazy flags
if (hasCrazyCodes)
{
WriteCrazyCodes(crazyCodes, bout);
// if we are writing unprintable codes after this, tack on another
// code
if (hasUnprintableCodes)
{
bout.Write(CRAZY_CODES_UNPRINT_SUFFIX);
}
}
// then we write all the unprintable extra bytes
if (hasUnprintableCodes)
{
// write another end flag
bout.Write(END_TEXT);
unprintableCodes.WriteTo(bout);
}
}
}
// handle descending order by inverting the bytes
if (!isAscending)
{
// we actually write the end byte before flipping the bytes, and write
// another one after flipping
bout.Write(END_EXTRA_TEXT);
// flip the bytes that we have written thus far for this text value
IndexData.FlipBytes(bout.GetBytes(), prevLength, (bout.GetLength() - prevLength));
}
// write end extra text
bout.Write(END_EXTRA_TEXT);
}
public virtual void WriteTo(ByteUtil.ByteStream @out)
{
@out.Write(_bytes, 0, _length);
}