/**
* Can we just receive a length to pad here? I don't like receiving
* sizeIdxRequest (or sizeIdx) this late in the game
*/
static void
PadRemainingInAscii(DmtxEncodeStream *stream, int sizeIdx)
{
int symbolRemaining;
DmtxByte padValue;
CHKSCHEME(DmtxSchemeAscii);
CHKSIZE;
symbolRemaining = GetRemainingSymbolCapacity(stream->output->length, sizeIdx);
/* First pad character is not randomized */
if(symbolRemaining > 0)
{
padValue = DmtxValueAsciiPad;
StreamOutputChainAppend(stream, padValue); CHKERR;
symbolRemaining--;
}
/* All remaining pad characters are randomized based on character position */
while(symbolRemaining > 0)
{
padValue = Randomize253State(DmtxValueAsciiPad, stream->output->length + 1);
StreamOutputChainAppend(stream, padValue); CHKERR;
symbolRemaining--;
}
}
static void
AppendValuesCTX(DmtxEncodeStream *stream, DmtxByteList *valueList)
{
int pairValue;
DmtxByte cw0, cw1;
if(!IsCTX(stream->currentScheme))
{
StreamMarkFatal(stream, DmtxErrorUnexpectedScheme);
return;
}
if(valueList->length < 3)
{
StreamMarkFatal(stream, DmtxErrorIncompleteValueList);
return;
}
/* Build codewords from computed value */
pairValue = (1600 * valueList->b[0]) + (40 * valueList->b[1]) + valueList->b[2] + 1;
cw0 = pairValue / 256;
cw1 = pairValue % 256;
/* Append 2 codewords */
StreamOutputChainAppend(stream, cw0); CHKERR;
StreamOutputChainAppend(stream, cw1); CHKERR;
/* Update count for 3 encoded values */
stream->outputChainValueCount += 3;
}
/**
* this code is separated from EncodeNextChunkAscii() because it needs to be
* called directly elsewhere
*/
static void
AppendValueAscii(DmtxEncodeStream *stream, DmtxByte value)
{
CHKSCHEME(DmtxSchemeAscii);
StreamOutputChainAppend(stream, value); CHKERR;
stream->outputChainValueCount++;
}
static void
AppendValueBase256(DmtxEncodeStream *stream, DmtxByte value)
{
CHKSCHEME(DmtxSchemeBase256);
StreamOutputChainAppend(stream, Randomize255State(value, stream->output->length + 1)); CHKERR;
stream->outputChainValueCount++;
UpdateBase256ChainHeader(stream, DmtxUndefined); CHKERR;
}
static void
AppendUnlatchCTX(DmtxEncodeStream *stream)
{
if(!IsCTX(stream->currentScheme))
{
StreamMarkFatal(stream, DmtxErrorUnexpectedScheme);
return;
}
/* Verify we are on byte boundary */
if(stream->outputChainValueCount % 3 != 0)
{
StreamMarkInvalid(stream, DmtxErrorNotOnByteBoundary);
return;
}
StreamOutputChainAppend(stream, DmtxValueCTXUnlatch); CHKERR;
stream->outputChainValueCount++;
}
static void
UpdateBase256ChainHeader(DmtxEncodeStream *stream, int perfectSizeIdx)
{
int headerIndex;
int outputLength;
int headerByteCount;
int symbolDataWords;
DmtxBoolean perfectFit;
DmtxByte headerValue0;
DmtxByte headerValue1;
outputLength = stream->outputChainValueCount;
headerIndex = stream->output->length - stream->outputChainWordCount;
headerByteCount = stream->outputChainWordCount - stream->outputChainValueCount;
perfectFit = (perfectSizeIdx == DmtxUndefined) ? DmtxFalse : DmtxTrue;
/*
* If requested perfect fit verify symbol capacity against final length
*/
if(perfectFit)
{
symbolDataWords = dmtxGetSymbolAttribute(DmtxSymAttribSymbolDataWords, perfectSizeIdx);
if(symbolDataWords != stream->output->length - 1)
{
StreamMarkFatal(stream, DmtxErrorUnknown);
return;
}
}
/*
* Adjust header to hold correct number of bytes, not worrying about the
* values held there until below. Note: Header bytes are not considered
* scheme "values" so we can insert or remove them without updating the
* outputChainValueCount.
*/
if(headerByteCount == 0 && stream->outputChainWordCount == 0)
{
/* No output words written yet -- insert single header byte */
StreamOutputChainAppend(stream, 0); CHKERR;
headerByteCount++;
}
else if(!perfectFit && headerByteCount == 1 && outputLength > 249)
{
/* Beyond 249 bytes requires a second header byte */
Base256OutputChainInsertFirst(stream); CHKERR;
headerByteCount++;
}
else if(perfectFit && headerByteCount == 2)
{
/* Encoding to exact end of symbol only requires single byte */
Base256OutputChainRemoveFirst(stream); CHKERR;
headerByteCount--;
}
/*
* Encode header byte(s) with current length
*/
if(!perfectFit && headerByteCount == 1 && outputLength <= 249)
{
/* Normal condition for chain length < 250 bytes */
headerValue0 = Randomize255State(outputLength, headerIndex + 1);
StreamOutputSet(stream, headerIndex, headerValue0); CHKERR;
}
else if(!perfectFit && headerByteCount == 2 && outputLength > 249)
{
/* Normal condition for chain length >= 250 bytes */
headerValue0 = Randomize255State(outputLength/250 + 249, headerIndex + 1);
StreamOutputSet(stream, headerIndex, headerValue0); CHKERR;
headerValue1 = Randomize255State(outputLength%250, headerIndex + 2);
StreamOutputSet(stream, headerIndex + 1, headerValue1); CHKERR;
}
else if(perfectFit && headerByteCount == 1)
{
/* Special condition when Base 256 stays in effect to end of symbol */
headerValue0 = Randomize255State(0, headerIndex + 1); /* XXX replace magic value 0? */
StreamOutputSet(stream, headerIndex, headerValue0); CHKERR;
}
else
{
StreamMarkFatal(stream, DmtxErrorUnknown);
return;
}
}
