Leaked source code of windows server 2003
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/****************************************************************************/
/* */
/* abccom.c */
/* */
/* Copyright (c) Data Connection Limited 1998 */
/* */
/* */
/* Bitmap compression routine and macros for 16 and 24bpp protocol */
/* */
/****************************************************************************/
/****************************************************************************/
/* We override the following macros to provide 16bpp/24bpp versions */
/* */
/* RUNSINGLE_NRM */
/* RunDouble */
/* RUNFGBG */
/* SETFGPEL */
/* ENCODE_SET_ORDER_MEGA */
/* ENCODE_SET_ORDER_FGBG */
/* ENCODEFGBG */
/****************************************************************************/
#ifdef BC_TRACE
#define BCTRACE TRC_DBG
#else
#define BCTRACE(string)
#endif
/****************************************************************************/
/* RUNSINGLE_NRM */
/* */
/* Determine the length of the current run */
/* */
/* RunSingle may only be called if the buffer has at least four */
/* consecutive identical pixels from the start position */
/* */
/* length is the number of bytes we should search */
/* result is the number of pixels found in the run */
/****************************************************************************/
#undef RUNSINGLE_NRM
#define RUNSINGLE_NRM(buffer, length, result) \
{ \
BYTE * buf = buffer + (BC_PIXEL_LEN * 4); \
BYTE * endbuf = buffer + length - (BC_PIXEL_LEN * 4); \
BC_PIXEL tmpPixel = BC_GET_PIXEL(buf - BC_PIXEL_LEN); \
\
result = 4; \
while (((buf + (BC_PIXEL_LEN - 1)) < endbuf) && \
(BC_GET_PIXEL(buf) == tmpPixel)) \
{ \
result++; \
buf += BC_PIXEL_LEN; \
} \
}
/****************************************************************************/
/* RunDouble */
/* */
/* Determine the length of the current run of paired bytes */
/* */
/* length is the number of bytes we should search */
/* result is the number of pixels found in the run */
/****************************************************************************/
#undef RunDouble
#define RunDouble(buffer, length, result) \
{ \
int len = ((short)length); \
BYTE * buf = buffer; \
BC_PIXEL testPel1 = BC_GET_PIXEL(buf); \
BC_PIXEL testPel2 = BC_GET_PIXEL(buf + BC_PIXEL_LEN); \
result = 0; \
while(len > BC_PIXEL_LEN) \
{ \
if (BC_GET_PIXEL(buf) != testPel1) \
{ \
break; \
} \
\
BC_TO_NEXT_PIXEL(buf); \
\
if (BC_GET_PIXEL(buf) != testPel2) \
{ \
break; \
} \
\
BC_TO_NEXT_PIXEL(buf); \
\
result += 2; \
len -= (BC_PIXEL_LEN * 2); \
} \
}
/****************************************************************************/
/* RUNFGBG */
/* */
/* Determine the length of the run of bytes that consist */
/* only of black or a single FG color */
/* We exit the loop when */
/* - the next character is not a fg or bg color */
/* - we hit a run of 24 of the FG or BG color when result is an exact */
/* multiple of eight (we'll be creating a bitmask of result bits long, */
/* hence this calculation) */
/* */
/* length is the number of bytes we should search */
/* result is the number of pixels in the run */
/* work is a BC_PIXEL for us to leave the fgPel in */
/****************************************************************************/
#undef RUNFGBG
#define RUNFGBG(buffer, length, result, work) \
{ \
BYTE * buf = buffer; \
BYTE * endbuf = buffer + length; \
int ii; \
BOOLEAN exitWhile = FALSE; \
BC_PIXEL tmpPixel; \
result = 0; \
work = BC_GET_PIXEL(buf); \
while(!exitWhile) \
{ \
BC_TO_NEXT_PIXEL(buf); \
result++; \
if (buf >= endbuf) \
{ \
break; \
} \
\
tmpPixel = BC_GET_PIXEL(buf); \
if ((tmpPixel != work) && (tmpPixel != (BC_PIXEL)0)) \
{ \
break; \
} \
\
if ((result & 0x0007) == 0) \
{ \
/***********************************************************/\
/* Check for 24 consecutive identical pixels starting at */\
/* buf */\
/* */\
/* We wouldn't have got this far unless */\
/* - the value we're checking for is 'work' */\
/* - the pixel at buf already contains 'work' */\
/***********************************************************/\
if ((buf + (24 * BC_PIXEL_LEN)) < endbuf) \
{ \
for (ii = BC_PIXEL_LEN; \
ii < (24 * BC_PIXEL_LEN); \
ii += BC_PIXEL_LEN) \
{ \
if (BC_GET_PIXEL(buf + ii) != work) \
{ \
break; \
} \
\
/***************************************************/\
/* Found them! Break out of the while loop. */\
/***************************************************/\
exitWhile = TRUE; \
} \
} \
} \
} \
}
/****************************************************************************/
/* SETFGPEL */
/* */
/* Set up a new value in fgPel. We don't calculate a shift as ENCODEFGBG */
/* doesn't need it in the 16/24bpp implementation. */
/* */
/* This is the hi-res version of SETFGCHAR. As the macros are named */
/* differently we will only need to undef this one on the second pass, */
/* hence the #ifdef/#endif surrounding it */
/****************************************************************************/
#ifdef SETFGPEL
#undef SETFGPEL
#endif
#define SETFGPEL(newPel, curPel) \
curPel = (BC_PIXEL)newPel;
/****************************************************************************/
/* ENCODE_SET_ORDER_MEGA */
/* */
/* Encode a combined order and set fg color */
/****************************************************************************/
#undef ENCODE_SET_ORDER_MEGA
#define ENCODE_SET_ORDER_MEGA(buffer, \
order_code, \
length, \
mega_order_code, \
DEF_LENGTH_ORDER, \
DEF_LENGTH_LONG_ORDER) \
if (length <= DEF_LENGTH_ORDER) \
{ \
*buffer++ = (BYTE)((BYTE)order_code | (BYTE)length); \
} \
else \
{ \
if (length <= DEF_LENGTH_LONG_ORDER) \
{ \
*buffer++ = (BYTE)order_code; \
*buffer++ = (BYTE)(length-DEF_LENGTH_ORDER-1); \
} \
else \
{ \
*buffer++ = (BYTE)mega_order_code; \
*(PUINT16_UA)(buffer) = (TSUINT16)length; \
buffer += 2; \
} \
} \
BC_SET_PIXEL(buffer, fgPel); \
BC_TO_NEXT_PIXEL(buffer);
/****************************************************************************/
/* Encode a combined order and set fg color for a special FGBG image */
/****************************************************************************/
#undef ENCODE_SET_ORDER_MEGA_FGBG
#define ENCODE_SET_ORDER_MEGA_FGBG(buffer, \
order_code, \
length, \
mega_order_code, \
DEF_LENGTH_ORDER, \
DEF_LENGTH_LONG_ORDER) \
if (((length & 0x0007) == 0) && \
(length <= DEF_LENGTH_ORDER)) \
{ \
*buffer++ = (BYTE)((BYTE)order_code | (BYTE)(length/8)); \
} \
else \
{ \
if (length <= DEF_LENGTH_LONG_ORDER) \
{ \
*buffer++ = (BYTE)order_code; \
*buffer++ = (BYTE)(length-1); \
} \
else \
{ \
*buffer++ = (BYTE)mega_order_code; \
*(PUINT16_UA)(buffer) = (TSUINT16)length; \
buffer += 2; \
} \
} \
BC_SET_PIXEL(buffer, fgPel); \
BC_TO_NEXT_PIXEL(buffer);
/****************************************************************************/
/* ENCODEFGBG */
/* */
/* Encode 8 pixels of FG and black into a one byte bitmap representation. */
/* */
/* We start reading at xorbuf[srcOffset] and don't try to be clever. */
/* */
/* We encode a row of pixels abcdefgh as a bitmask thus: */
/* */
/* bit 7 6 5 4 3 2 1 0 */
/* pel h g f e d c b a */
/* */
/* where 7 is the most significant bit. */
/* */
/****************************************************************************/
#undef ENCODEFGBG
#define ENCODEFGBG(result) \
{ \
BYTE * buf = xorbuf + srcOffset; \
\
result = 0; \
\
if (BC_GET_PIXEL(buf) != (BC_PIXEL)0) \
{ \
result |= 0x01; \
} \
BC_TO_NEXT_PIXEL(buf); \
\
if (BC_GET_PIXEL(buf) != (BC_PIXEL)0) \
{ \
result |= 0x02; \
} \
BC_TO_NEXT_PIXEL(buf); \
\
if (BC_GET_PIXEL(buf) != (BC_PIXEL)0) \
{ \
result |= 0x04; \
} \
BC_TO_NEXT_PIXEL(buf); \
\
if (BC_GET_PIXEL(buf) != (BC_PIXEL)0) \
{ \
result |= 0x08; \
} \
BC_TO_NEXT_PIXEL(buf); \
\
if (BC_GET_PIXEL(buf) != (BC_PIXEL)0) \
{ \
result |= 0x10; \
} \
BC_TO_NEXT_PIXEL(buf); \
\
if (BC_GET_PIXEL(buf) != (BC_PIXEL)0) \
{ \
result |= 0x20; \
} \
BC_TO_NEXT_PIXEL(buf); \
\
if (BC_GET_PIXEL(buf) != (BC_PIXEL)0) \
{ \
result |= 0x40; \
} \
BC_TO_NEXT_PIXEL(buf); \
\
if (BC_GET_PIXEL(buf) != (BC_PIXEL)0) \
{ \
result |= 0x80; \
} \
BC_TO_NEXT_PIXEL(buf); \
}
/****************************************************************************/
/* Compress function starts here */
/****************************************************************************/
/****************************************************************************/
/* */
/* BYTE * pSrc, */
/* BYTE * pDst, */
/* unsigned numBytes, total bytes in image */
/* unsigned rowDelta, scanline length in bytes */
/* unsigned dstBufferSize, */
/* unsigned * xorbuf, */
/* MATCH * match */
/* */
/****************************************************************************/
{
int i;
unsigned srcOffset;
unsigned matchindex;
unsigned bestRunLength;
unsigned nextRunLength;
unsigned runLength;
unsigned bestFGRunLength;
unsigned checkFGBGLength;
unsigned scanCount;
BOOLEAN firstLine;
unsigned saveNumBytes;
BYTE bestRunType = 0;
BYTE * destbuf = pDst;
BC_PIXEL fgPel = BC_DEFAULT_FGPEL;
BC_PIXEL fgPelWork = BC_DEFAULT_FGPEL;
BOOLEAN inColorRun = FALSE;
unsigned compressedLength = 0;
BC_PIXEL pixelA;
BC_PIXEL pixelB;
DC_BEGIN_FN(BC_FN_NAME);
/************************************************************************/
/* Validate the line length */
/************************************************************************/
if ((numBytes < rowDelta) ||
(rowDelta & 0x0003) || (numBytes & 0x0003) ||
((numBytes % BC_PIXEL_LEN) != 0))
{
TRC_ALT((TB, "Lines must be a multiple of 4 pels and there must be"
" a whole number of pixels in the buffer"
" (numBytes = %d, rowDelta = %d)", numBytes, rowDelta));
DC_QUIT;
}
/************************************************************************/
/* The first line of the XORBUF is identical to the first line of the */
/* source buffer. Set it up. */
/************************************************************************/
memcpy(xorbuf, pSrc, rowDelta);
/************************************************************************/
/* The remaining lines in the XORBUF are the XOR against the previous */
/* line. Calculate the rest of the XOR buffer. */
/* */
/* Note that this calculation is NOT pel-size dependent */
/************************************************************************/
{
BYTE * srcbuf = pSrc + rowDelta;
unsigned srclen = numBytes - rowDelta;
UINT32 * dwdest = (UINT32 *)(xorbuf + rowDelta);
while (srclen >= 8)
{
*dwdest++ = *((PUINT32)srcbuf) ^ *((PUINT32)(srcbuf - rowDelta));
srcbuf += 4;
*dwdest++ = *((PUINT32)srcbuf) ^ *((PUINT32)(srcbuf - rowDelta));
srcbuf += 4;
srclen -= 8;
}
if (srclen)
{
// Since we're 4-byte aligned we can only have a single DWORD
// remaining.
*dwdest = *((PUINT32)srcbuf) ^ *((PUINT32)(srcbuf - rowDelta));
}
}
/************************************************************************/
/* Loop processing the input */
/* We perform the loop twice, the first time for the non-xor portion */
/* of the buffer and the second for the XOR portion */
/* */
/* Note that we start the run at a match index of 2 to avoid having */
/* to special case the startup condition in some of the match */
/* merging code */
/************************************************************************/
srcOffset = 0;
firstLine = TRUE;
match[0].type = 0;
match[1].type = 0;
matchindex = 2;
saveNumBytes = numBytes;
/************************************************************************/
/* On the first iteration numBytes stores the length of a scanline, on */
/* the second the total number of bytes. */
/* */
/* srcOffset is the position we are currently examining. */
/************************************************************************/
numBytes = rowDelta;
for (scanCount = 0; scanCount < 2; scanCount++)
{
while (srcOffset < numBytes)
{
/****************************************************************/
/* Give up if we are nearing the end of the match array */
/****************************************************************/
if (matchindex >= 8192)
{
DC_QUIT;
}
/****************************************************************/
/* Start a while loop to allow a more structured break when we */
/* hit the first run type we want to encode (We can't afford */
/* the overheads of a function call to provide the scope here.) */
/****************************************************************/
while (TRUE)
{
bestRunLength = 0;
bestFGRunLength = 0;
/************************************************************/
/* If we are hitting the end of the buffer then just take */
/* color characters now - take them one at a time so that */
/* lossy encoding still works. We will only hit this */
/* condition if we break out of a run just before the end */
/* of the buffer, so this should not be too common a */
/* situation, which is good given that we are encoding the */
/* final 6 pixels uncompressed. */
/************************************************************/
if (srcOffset + (6 * BC_PIXEL_LEN) >= numBytes)
{
bestRunType = IMAGE_COLOR;
bestRunLength = 1;
break;
}
/************************************************************/
/* First do the scans on the XOR buffer. Look for a */
/* character run or a BG run. Note that if there is no row */
/* delta then xorbuf actually points to the normal buffer. */
/* We must do the test independent of how long the run */
/* might be because even for a 1 pel BG run our later logic */
/* requires that we detect it separately. This code is */
/* absolute main path so fastpath as much as possible. In */
/* particular detect short bg runs early and allow */
/* RunSingle to presuppose at least 4 matching bytes */
/************************************************************/
if (BC_GET_PIXEL(xorbuf + srcOffset) == (BC_PIXEL)0)
{
/********************************************************/
/* First pixel is 0, so look for BG runs */
/********************************************************/
if (((srcOffset + BC_PIXEL_LEN) >= numBytes) ||
(BC_GET_PIXEL(xorbuf + srcOffset + BC_PIXEL_LEN) !=
(BC_PIXEL)0))
{
/****************************************************/
/* One pixel BG run */
/****************************************************/
bestRunType = RUN_BG;
bestRunLength = 1;
if (!inColorRun)
{
break;
}
}
else if (((srcOffset + (BC_PIXEL_LEN * 2)) >= numBytes) ||
(BC_GET_PIXEL(xorbuf +
srcOffset +
(BC_PIXEL_LEN * 2)) != (BC_PIXEL)0))
{
/****************************************************/
/* Two pixel BG run */
/****************************************************/
bestRunType = RUN_BG;
bestRunLength = 2;
if (!inColorRun)
{
break;
}
}
else if (((srcOffset + (BC_PIXEL_LEN * 3)) >= numBytes) ||
(BC_GET_PIXEL(xorbuf +
srcOffset +
(BC_PIXEL_LEN * 3)) != (BC_PIXEL)0))
{
/****************************************************/
/* Three pixel BG run */
/****************************************************/
bestRunType = RUN_BG;
bestRunLength = 3;
if (!inColorRun)
{
break;
}
}
else
{
/****************************************************/
/* Four or more pixel BG run */
/****************************************************/
RUNSINGLE_NRM(xorbuf + srcOffset,
numBytes - srcOffset,
bestFGRunLength);
CHECK_BEST_RUN(RUN_BG,
bestFGRunLength,
bestRunLength,
bestRunType);
if (!inColorRun)
{
break;
}
}
}
else
{
/********************************************************/
/* First pixel is non-zero, so look for FG runs */
/********************************************************/
/********************************************************/
/* No point in starting if FG run less than 4 bytes so */
/* check the first dword as quickly as possible Note */
/* that we don't need to check for an end-buffer */
/* condition here because our XOR buffer always has */
/* some free space at the end and the RUNSINGLE_NRM */
/* will break at the correct place */
/********************************************************/
BC_PIXEL tmpPixel = BC_GET_PIXEL(xorbuf + srcOffset);
if ( (tmpPixel ==
BC_GET_PIXEL(xorbuf + srcOffset + BC_PIXEL_LEN)) &&
(tmpPixel ==
BC_GET_PIXEL(xorbuf +
srcOffset +
(BC_PIXEL_LEN * 2))) &&
(tmpPixel ==
BC_GET_PIXEL(xorbuf +
srcOffset +
(BC_PIXEL_LEN * 3))) )
{
RUNSINGLE_NRM(xorbuf + srcOffset,
numBytes - srcOffset,
bestFGRunLength);
/****************************************************/
/* Don't permit a short FG run to prevent a FGBG */
/* image from starting up. Only take if >= 5 */
/****************************************************/
if (bestFGRunLength > 5)
{
CHECK_BEST_RUN(RUN_FG,
bestFGRunLength,
bestRunLength,
bestRunType);
}
}
}
/************************************************************/
/* Look for color runs and dithered runs. */
/* */
/* Start by checking for the pattern */
/* A B A B A B */
/* */
/* If we find it, then if A == B, it's a color run else */
/* it's a dithered run. */
/* */
/* Look for sequences in the non XOR buffer In this case we */
/* insist upon a run of at least 6 pels */
/************************************************************/
pixelA = BC_GET_PIXEL(pSrc + srcOffset);
pixelB = BC_GET_PIXEL(pSrc + srcOffset + BC_PIXEL_LEN);
if ( (pixelA ==
BC_GET_PIXEL(pSrc + srcOffset + (BC_PIXEL_LEN * 2))) &&
(pixelA ==
BC_GET_PIXEL(pSrc + srcOffset + (BC_PIXEL_LEN * 4))) &&
(pixelB ==
BC_GET_PIXEL(pSrc + srcOffset + (BC_PIXEL_LEN * 3))) &&
(pixelB ==
BC_GET_PIXEL(pSrc + srcOffset + (BC_PIXEL_LEN * 5))) )
{
/********************************************************/
/* Now do the scan on the normal buffer for a character */
/* run Don't bother if first line because we will have */
/* found it already in the XOR buffer, since we just */
/* copy pSrc to xorbuf for the first line */
/********************************************************/
if (pixelA == pixelB)
{
if (!firstLine)
{
RUNSINGLE_NRM(pSrc + srcOffset,
numBytes - srcOffset,
nextRunLength);
if (nextRunLength > 5)
{
CHECK_BEST_RUN(RUN_COLOR,
nextRunLength,
bestRunLength,
bestRunType);
}
}
}
else
{
/****************************************************/
/* Look for a dither on the nrm buffer. Dithers */
/* are not very efficient for short runs so only */
/* take if 8 or longer */
/****************************************************/
RunDouble(pSrc + srcOffset,
numBytes - srcOffset,
nextRunLength);
if (nextRunLength > 9)
{
CHECK_BEST_RUN(RUN_DITHER,
nextRunLength,
bestRunLength,
bestRunType);
}
}
}
/************************************************************/
/* If nothing so far then look for a FGBG run (The 6 is */
/* carefully tuned!) */
/************************************************************/
if (bestRunLength < 6)
{
/********************************************************/
/* But first look for a single fg bit breaking up a BG */
/* run. If so then encode a BG run. Careful of the */
/* enforced BG run break across the first line */
/* non-XOR/XOR boundary. */
/* */
/* So... */
/* - check that the next four pixels are 0 (BG) */
/* - check that the pel in the middle is the fgPel */
/* - check that the previous run code is indeed RUN_BG */
/* - check for the break over the boundary */
/********************************************************/
if ( (BC_GET_PIXEL(xorbuf +
srcOffset +
BC_PIXEL_LEN) == (BC_PIXEL)0) &&
(BC_GET_PIXEL(xorbuf +
srcOffset +
(BC_PIXEL_LEN * 2)) == (BC_PIXEL)0) &&
(BC_GET_PIXEL(xorbuf +
srcOffset +
(BC_PIXEL_LEN * 3)) == (BC_PIXEL)0) &&
(BC_GET_PIXEL(xorbuf +
srcOffset +
(BC_PIXEL_LEN * 4)) == (BC_PIXEL)0) &&
(BC_GET_PIXEL(xorbuf + srcOffset) == fgPel) &&
(match[matchindex-1].type == RUN_BG) &&
(srcOffset != (TSUINT16)rowDelta))
{
RUNSINGLE_NRM(xorbuf + srcOffset + BC_PIXEL_LEN,
numBytes - srcOffset - BC_PIXEL_LEN,
nextRunLength);
nextRunLength++;
CHECK_BEST_RUN(RUN_BG_PEL,
nextRunLength,
bestRunLength,
bestRunType);
}
else
{
/****************************************************/
/* If we have not found a run then look for a FG/BG */
/* image. The disruptive effect of a short FGBG */
/* run bandwidth and CPU is such that it is worth */
/* preventing one unless we are certain of the */
/* benefits. However, if the alternative is a */
/* color run then allow a lower value. */
/****************************************************/
BCTRACE((TB, "FGBG: Checking %d bytes",
numBytes - srcOffset));
RUNFGBG(xorbuf + srcOffset,
numBytes - srcOffset,
nextRunLength,
fgPelWork);
checkFGBGLength = 48;
if (fgPelWork == fgPel)
{
/************************************************/
/* Cool: we don't need to issue a SET directive */
/* as the fgPel is correct. */
/************************************************/
checkFGBGLength -= 16;
}
if ((nextRunLength & 0x0007) == 0)
{
/************************************************/
/* Our bitmask will fit in an exact number of */
/* bytes. This is a Good Thing. */
/************************************************/
checkFGBGLength -= 8;
}
BCTRACE((TB, "FGBG: resulting run %d, checklen %d ",
nextRunLength, checkFGBGLength ));
if (nextRunLength >= checkFGBGLength)
{
CHECK_BEST_RUN(IMAGE_FGBG,
nextRunLength,
bestRunLength,
bestRunType);
BCTRACE((TB, "FGBG: resulting best run %d, type %d",
bestRunLength, bestRunType ));
}
}
}
/************************************************************/
/* If nothing useful so far then allow a short run, if any. */
/* Don't do this if we are accumulating a color run because */
/* it will really screw up GDC compression if we allow lots */
/* of little runs. Also require that it is a regular short */
/* run, rather than one that disturbs the fgPel. */
/************************************************************/
if (!inColorRun)
{
if (bestRunLength < 6)
{
if ((bestFGRunLength > 4) &&
(BC_GET_PIXEL(xorbuf + srcOffset) == fgPel))
{
/************************************************/
/* We mustn't merge with the previous code */
/* if we have just crossed the non-XOR/XOR */
/* boundary. */
/************************************************/
if ((match[matchindex-1].type == RUN_FG) &&
(srcOffset != rowDelta))
{
match[matchindex-1].length += bestFGRunLength;
srcOffset += (bestFGRunLength * BC_PIXEL_LEN);
continue;
}
else
{
bestRunLength = bestFGRunLength;
bestRunType = RUN_FG;
}
}
else
{
/************************************************/
/* If we decided to take a run earlier then */
/* allow it now. (May be a short BG run, for */
/* example) If nothing so far then take color */
/* image) */
/************************************************/
if (bestRunLength == 0)
{
bestRunType = IMAGE_COLOR;
bestRunLength = 1;
}
}
}
}
else if ((bestRunLength < 6) ||
((bestRunType != RUN_BG) && (bestRunLength < 8)))
{
bestRunType = IMAGE_COLOR;
bestRunLength = 1;
}
break;
}
/****************************************************************/
/* When we get here we have found the best run. Now check for */
/* various amalamation conditions with the previous run type. */
/* Note that we may already have done amalgamation of short */
/* runs, but we had to do multiple samples for the longer runs */
/* so we repeat the checks here */
/****************************************************************/
/****************************************************************/
/* If we are encoding a color run then */
/* - combine it with an existing run if possible */
/****************************************************************/
if (bestRunType == IMAGE_COLOR)
{
/************************************************************/
/* Flag that we are within a color run */
/************************************************************/
inColorRun = TRUE;
/************************************************************/
/* Merge the color run immediately, if possible */
/************************************************************/
if (match[matchindex-1].type == IMAGE_COLOR)
{
match[matchindex-1].length += bestRunLength;
srcOffset += (bestRunLength * BC_PIXEL_LEN);
continue;
}
}
else
{
/************************************************************/
/* We are no longer encoding a COLOR_IMAGE of any kind */
/************************************************************/
inColorRun = FALSE;
/************************************************************/
/* Keep track of the fg Color. The macro that searches for */
/* FGBG runs leaves the character in fgPelWork. */
/************************************************************/
if (bestRunType == RUN_FG)
{
fgPel = BC_GET_PIXEL(xorbuf + srcOffset);
}
else if (bestRunType == IMAGE_FGBG)
{
fgPel = fgPelWork;
}
}
/****************************************************************/
/* If we can amalgamate the entry then do so without creating a */
/* new array entry insertion. Our search for FGBG runs is */
/* dependent upon that type of run being amalgamated because we */
/* break every 64 characters so that our mode switch detection */
/* works OK. */
/* */
/* Take care not to merge across the non-xor/xor boundary */
/****************************************************************/
if (srcOffset == (TSUINT16)rowDelta)
{
/************************************************************/
/* Just bump the source offset */
/************************************************************/
srcOffset += (bestRunLength * BC_PIXEL_LEN);
}
else
{
/************************************************************/
/* Bump srcOffset and try a merge */
/************************************************************/
srcOffset += (bestRunLength * BC_PIXEL_LEN);
/************************************************************/
/* The simpler merges are where the types are identical */
/************************************************************/
if (bestRunType == match[matchindex-1].type)
{
/********************************************************/
/* COLOR IMAGES and BG images are trivial */
/********************************************************/
if (bestRunType == RUN_BG)
{
match[matchindex-1].length += bestRunLength;
continue;
}
/********************************************************/
/* FG runs and FGBG images merge if fgPels match */
/********************************************************/
if (((bestRunType == RUN_FG) ||
(bestRunType == IMAGE_FGBG)) &&
(fgPel == match[matchindex-1].fgPel))
{
match[matchindex-1].length += bestRunLength;
BCTRACE((TB, "Merged %u with preceding, giving %u",
match[matchindex-1].type,
match[matchindex-1].length));
continue;
}
}
/************************************************************/
/* BG RUNs merge with LOSSY odd lines It is important that */
/* we do this merging because otherwise we will get */
/* inadvertent pel insertion due to the broken BG runs. */
/************************************************************/
if ((bestRunType == RUN_BG) &&
((match[matchindex-1].type == RUN_BG) ||
(match[matchindex-1].type == RUN_BG_PEL)))
{
match[matchindex-1].length += bestRunLength;
continue;
}
/************************************************************/
/* If it is a normal FGBG run which follows a short BG run */
/* then it is better to merge them. */
/************************************************************/
if ((bestRunType == IMAGE_FGBG) &&
(match[matchindex-1].type == RUN_BG) &&
(match[matchindex-1].length < 8))
{
match[matchindex-1].type = IMAGE_FGBG;
match[matchindex-1].length += bestRunLength;
match[matchindex-1].fgPel = fgPel;
BCTRACE((TB, "Merged FGBG with preceding BG run -> %u",
match[matchindex-1].length));
continue;
}
/************************************************************/
/* If it is a BG run following a FGBG run then merge in the */
/* pels to make the FGBG a multiple of 8 bits. The if the */
/* remaining BG run is < 16 merge it in also otherwise just */
/* write the shortened BG run */
/************************************************************/
if (((bestRunType == RUN_BG) ||
(bestRunType == RUN_BG_PEL)) &&
(match[matchindex-1].type == IMAGE_FGBG) &&
(match[matchindex-1].length & 0x0007))
{
/********************************************************/
/* mergelen is the number of pixels we want to merge. */
/********************************************************/
unsigned mergelen = 8 -
(match[matchindex-1].length & 0x0007);
if (mergelen > bestRunLength)
{
mergelen = bestRunLength;
}
match[matchindex-1].length += mergelen;
bestRunLength -= mergelen;
BCTRACE((TB, "Added %u pels to FGBG giving %u leaving %u",
mergelen, match[matchindex-1].length,bestRunLength));
if (bestRunLength < 9)
{
match[matchindex-1].length += bestRunLength;
BCTRACE((TB, "Merged BG with preceding FGBG gives %u",
match[matchindex-1].length));
continue;
}
}
/************************************************************/
/* Finally, if it is a color run spanning any kind of */
/* single pel entity then merge that last two entries. */
/************************************************************/
if ((bestRunType == IMAGE_COLOR) &&
(match[matchindex-2].type == IMAGE_COLOR) &&
(match[matchindex-1].length == 1))
{
match[matchindex-2].length += bestRunLength + 1;
matchindex--;
BCTRACE((TB, "Merged color with preceding color gives %u",
match[matchindex-1].length));
continue;
}
}
/****************************************************************/
/* Handle runs that will not amalgamate by adding a new array */
/* entry */
/****************************************************************/
match[matchindex].type = bestRunType;
match[matchindex].length = bestRunLength;
match[matchindex].fgPel = fgPel;
BCTRACE((TB, "Best run of type %u (index %u) has length %u",
match[matchindex-1].type,
matchindex-1,
match[matchindex-1].length));
BCTRACE((TB, "Trying run of type %u (index %u) length %u",
match[matchindex].type,
matchindex,
match[matchindex].length));
matchindex++;
}
/********************************************************************/
/* If we have just done our scan of the first line then now do the */
/* rest of the buffer. Reset our saved pel count. */
/********************************************************************/
numBytes = saveNumBytes;
firstLine = FALSE;
}
/************************************************************************/
/* END OF INITIAL TWO PASS SCAN OF THE INPUT */
/************************************************************************/
/************************************************************************/
/* Now do the encoding */
/************************************************************************/
srcOffset = 0;
firstLine = TRUE;
fgPel = BC_DEFAULT_FGPEL;
for (i = 2; i < (int)matchindex; i++)
{
/********************************************************************/
/* First check for our approaching the end of the destination */
/* buffer and get out if this is the case. We allow for the */
/* largest general run order (a mega-mega set run = 3 bytes + pixel */
/* length). Orders which may be larger are checked within the case */
/* arm */
/********************************************************************/
if ((unsigned)(destbuf - pDst + 3 + BC_PIXEL_LEN) > dstBufferSize)
{
/****************************************************************/
/* We are about to blow it so just get out */
/****************************************************************/
DC_QUIT;
}
/********************************************************************/
/* While we are encoding the first line keep checking for the end */
/* of line to switch encoding states */
/********************************************************************/
if (firstLine)
{
if (srcOffset >= rowDelta)
{
firstLine = FALSE;
}
}
switch (match[i].type)
{
/************************************************************/
/* BG_RUN, FG_RUN, COLOR, PACKED COLOR and FGBG are normal */
/* precision codes */
/************************************************************/
case RUN_BG:
case RUN_BG_PEL:
ENCODE_ORDER_MEGA(destbuf,
CODE_BG_RUN,
match[i].length,
CODE_MEGA_MEGA_BG_RUN,
MAX_LENGTH_ORDER,
MAX_LENGTH_LONG_ORDER);
BCTRACE((TB, "BG_RUN %u",match[i].length));
srcOffset += (match[i].length * BC_PIXEL_LEN);
break;
case RUN_FG:
/************************************************************/
/* If the fg char is not yet set then encode a set+run code */
/************************************************************/
if (fgPel != match[i].fgPel)
{
SETFGPEL(match[i].fgPel, fgPel);
/********************************************************/
/* Encode the order */
/********************************************************/
ENCODE_SET_ORDER_MEGA(destbuf,
CODE_SET_FG_FG_RUN,
match[i].length,
CODE_MEGA_MEGA_SET_FG_RUN,
MAX_LENGTH_ORDER_LITE,
MAX_LENGTH_LONG_ORDER_LITE);
BCTRACE((TB, "SET_FG_FG_RUN %u",match[i].length));
srcOffset += (match[i].length * BC_PIXEL_LEN);
}
else
{
ENCODE_ORDER_MEGA(destbuf,
CODE_FG_RUN,
match[i].length,
CODE_MEGA_MEGA_FG_RUN,
MAX_LENGTH_ORDER,
MAX_LENGTH_LONG_ORDER);
BCTRACE((TB, "FG_RUN %u",match[i].length));
srcOffset += (match[i].length * BC_PIXEL_LEN);
}
break;
case IMAGE_FGBG:
/************************************************************/
/* IMAGE_FGBG */
/************************************************************/
runLength = match[i].length;
/************************************************************/
/* First check for our approaching the end of the */
/* destination buffer and get out if this is the case. */
/* */
/* The IMAGE_FGBG consists of a set of byte-long bit masks */
/* designed to hold runLength bits. */
/************************************************************/
if ((destbuf - pDst + ((runLength+7)/8) + 3 + BC_PIXEL_LEN)
> dstBufferSize)
{
/********************************************************/
/* We are about to blow it so just get out */
/********************************************************/
DC_QUIT;
}
if (fgPel != match[i].fgPel)
{
/********************************************************/
/* We need to include a SET directive as fgPel has */
/* changed */
/********************************************************/
SETFGPEL(match[i].fgPel, fgPel);
ENCODE_SET_ORDER_MEGA_FGBG(destbuf,
CODE_SET_FG_FG_BG,
runLength,
CODE_MEGA_MEGA_SET_FGBG,
MAX_LENGTH_FGBG_ORDER_LITE,
MAX_LENGTH_LONG_FGBG_ORDER);
BCTRACE((TB, "SET_FG_FG_BG %u, fgPel %06lx",
match[i].length, fgPel));
/********************************************************/
/* For every eight pixels... */
/********************************************************/
while (runLength >= 8)
{
ENCODEFGBG(*destbuf);
BCTRACE((TB, "Encoded as %08lx", *destbuf));
destbuf++;
srcOffset += (8 * BC_PIXEL_LEN);
runLength -= 8;
}
if (runLength)
{
ENCODEFGBG(*destbuf);
/****************************************************/
/* Keep the final partial byte clean to help GDC */
/* packing */
/****************************************************/
*destbuf &= ((0x01 << runLength) - 1);
destbuf++;
srcOffset += (runLength * BC_PIXEL_LEN);
}
}
else
{
/********************************************************/
/* fgPel is already the correct value */
/********************************************************/
if (runLength == 8)
{
BYTE fgbgChar;
/****************************************************/
/* See if it is one of the high probability bytes */
/****************************************************/
ENCODEFGBG(fgbgChar);
/****************************************************/
/* Check for single byte encoding of FGBG images */
/****************************************************/
switch (fgbgChar)
{
case SPECIAL_FGBG_CODE_1:
*destbuf++ = CODE_SPECIAL_FGBG_1;
BCTRACE((TB, "SPECIAL FGBG_1"));
break;
case SPECIAL_FGBG_CODE_2:
*destbuf++ = CODE_SPECIAL_FGBG_2;
BCTRACE((TB, "SPECIAL FGBG_2"));
break;
default:
ENCODE_ORDER_MEGA_FGBG(destbuf,
CODE_FG_BG_IMAGE,
runLength,
CODE_MEGA_MEGA_FGBG,
MAX_LENGTH_FGBG_ORDER,
MAX_LENGTH_LONG_FGBG_ORDER);
*destbuf++ = fgbgChar;
break;
}
srcOffset += (8 * BC_PIXEL_LEN);
}
else
{
/****************************************************/
/* Encode as standard FGBG */
/****************************************************/
ENCODE_ORDER_MEGA_FGBG(destbuf,
CODE_FG_BG_IMAGE,
runLength,
CODE_MEGA_MEGA_FGBG,
MAX_LENGTH_FGBG_ORDER,
MAX_LENGTH_LONG_FGBG_ORDER);
BCTRACE((TB, "FG_BG %u",match[i].length));
while (runLength >= 8)
{
ENCODEFGBG(*destbuf);
destbuf++;
srcOffset += (8 * BC_PIXEL_LEN);
runLength -= 8;
}
if (runLength)
{
/************************************************/
/* Keep the final partial byte clean to help */
/* GDC packing */
/************************************************/
ENCODEFGBG(*destbuf);
*destbuf &= ((0x01 << runLength) - 1);
destbuf++;
srcOffset += (runLength * BC_PIXEL_LEN);
}
}
}
break;
case RUN_COLOR:
/************************************************************/
/* COLOR RUN */
/************************************************************/
ENCODE_ORDER_MEGA(destbuf,
CODE_COLOR_RUN,
match[i].length,
CODE_MEGA_MEGA_COLOR_RUN,
MAX_LENGTH_ORDER,
MAX_LENGTH_LONG_ORDER);
BCTRACE((TB, "COLOR_RUN %u",match[i].length));
BC_SET_PIXEL(destbuf, BC_GET_PIXEL(pSrc + srcOffset));
BC_TO_NEXT_PIXEL(destbuf);
srcOffset += (match[i].length * BC_PIXEL_LEN);
break;
case RUN_DITHER:
/************************************************************/
/* DITHERED RUN */
/************************************************************/
{
unsigned ditherlen = match[i].length/2;
ENCODE_ORDER_MEGA(destbuf,
CODE_DITHERED_RUN,
ditherlen,
CODE_MEGA_MEGA_DITHER,
MAX_LENGTH_ORDER_LITE,
MAX_LENGTH_LONG_ORDER_LITE);
BCTRACE((TB, "DITHERED_RUN %u",match[i].length));
/********************************************************/
/* First check for our approaching the end of the */
/* destination buffer and get out if this is the case. */
/********************************************************/
if ((unsigned)(destbuf - pDst + (2 * BC_PIXEL_LEN))
> dstBufferSize)
{
/****************************************************/
/* We are about to blow it so just get out */
/****************************************************/
DC_QUIT;
}
/********************************************************/
/* Put the two pixels to dither with into the output */
/* buffer */
/********************************************************/
BC_SET_PIXEL(destbuf, BC_GET_PIXEL(pSrc + srcOffset));
BC_TO_NEXT_PIXEL(destbuf);
BC_SET_PIXEL(destbuf,
BC_GET_PIXEL(pSrc + srcOffset + BC_PIXEL_LEN));
BC_TO_NEXT_PIXEL(destbuf);
srcOffset += (match[i].length * BC_PIXEL_LEN);
}
break;
case IMAGE_COLOR:
/************************************************************/
/* IMAGE_COLOR */
/************************************************************/
/************************************************************/
/* A length of 1 can possibly be encoded as a single */
/* "BLACK" or "WHITE" */
/************************************************************/
if (match[i].length == 1)
{
if (BC_GET_PIXEL(pSrc + srcOffset) == (BC_PIXEL)0)
{
*destbuf++ = CODE_BLACK;
srcOffset += BC_PIXEL_LEN;
BCTRACE((TB, "CODE_BLACK"));
break;
}
if (BC_GET_PIXEL(pSrc + srcOffset) == BC_DEFAULT_FGPEL)
{
*destbuf++ = CODE_WHITE;
srcOffset += BC_PIXEL_LEN;
BCTRACE((TB, "CODE_WHITE"));
break;
}
}
ENCODE_ORDER_MEGA(destbuf,
CODE_COLOR_IMAGE,
match[i].length,
CODE_MEGA_MEGA_CLR_IMG,
MAX_LENGTH_ORDER,
MAX_LENGTH_LONG_ORDER);
BCTRACE((TB, "COLOR_IMAGE %u",match[i].length));
/************************************************************/
/* First check for our approaching the end of the */
/* destination buffer and get out if this is the case. */
/************************************************************/
if ((destbuf - pDst + (match[i].length * BC_PIXEL_LEN))
> dstBufferSize)
{
/********************************************************/
/* We are about to blow it so just get out */
/********************************************************/
DC_QUIT;
}
/************************************************************/
/* Now just copy the data over */
/************************************************************/
memcpy(destbuf,
pSrc + srcOffset,
match[i].length * BC_PIXEL_LEN);
destbuf += match[i].length * BC_PIXEL_LEN;
srcOffset += match[i].length * BC_PIXEL_LEN;
break;
default:
{
TRC_ERR((TB, "Invalid run type %u",match[i].type));
}
}
}
/************************************************************************/
/* return the size of the compressed buffer */
/************************************************************************/
compressedLength = (unsigned)(destbuf - pDst);
DC_EXIT_POINT:
DC_END_FN();
return compressedLength;
}