/// <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>Encodes the given extra code info in the given stream.</summary>
/// <remarks>Encodes the given extra code info in the given stream.</remarks>
/// <exception cref="System.IO.IOException"></exception>
private static void WriteExtraCodes(int charOffset, byte[] bytes, byte extraCodeModifier
, GeneralLegacyIndexCodes.ExtraCodesStream extraCodes)
{
// we fill in a placeholder value for any chars w/out extra codes
int numChars = extraCodes.GetNumChars();
if (numChars < charOffset)
{
int fillChars = charOffset - numChars;
extraCodes.WriteFill(fillChars, INTERNATIONAL_EXTRA_PLACEHOLDER);
extraCodes.IncrementNumChars(fillChars);
}
if (bytes != null)
{
// write the actual extra codes and update the number of chars
extraCodes.Write(bytes);
extraCodes.IncrementNumChars(1);
}
else
{
// extra code modifiers modify the existing extra code bytes and do not
// count as additional extra code chars
int lastIdx = extraCodes.GetLength() - 1;
if (lastIdx >= 0)
{
// the extra code modifier is added to the last extra code written
byte lastByte = extraCodes.Get(lastIdx);
lastByte += extraCodeModifier;
extraCodes.Set(lastIdx, lastByte);
}
else
{
// there is no previous extra code, add a new code (but keep track of
// this "unprintable code" prefix)
extraCodes.Write(extraCodeModifier);
extraCodes.SetUnprintablePrefixLen(1);
}
}
}