jbig2stream.cc

这是一个做pdf阅读器的源代码文件,是大家学习阅读器资料的很好参考

      huffAggInstTable =
	  ((JBIG2CodeTable *)codeTables->get(i++))->getHuffTable();
    }
  }
  delete codeTables;

  // set up the Huffman decoder
  if (huff) {
    huffDecoder->reset();

  // set up the arithmetic decoder
  } else {
    if (contextUsed && inputSymbolDict) {
      resetGenericStats(sdTemplate, inputSymbolDict->getGenericRegionStats());
    } else {
      resetGenericStats(sdTemplate, NULL);
    }
    resetIntStats(symCodeLen);
    arithDecoder->start();
  }

  // set up the arithmetic decoder for refinement/aggregation
  if (refAgg) {
    if (contextUsed && inputSymbolDict) {
      resetRefinementStats(sdrTemplate,
			   inputSymbolDict->getRefinementRegionStats());
    } else {
      resetRefinementStats(sdrTemplate, NULL);
    }
  }

  // allocate symbol widths storage
  symWidths = NULL;
  if (huff && !refAgg) {
    symWidths = (Guint *)gmallocn(numNewSyms, sizeof(Guint));
  }

  symHeight = 0;
  i = 0;
  while (i < numNewSyms) {

    // read the height class delta height
    if (huff) {
      huffDecoder->decodeInt(&dh, huffDHTable);
    } else {
      arithDecoder->decodeInt(&dh, iadhStats);
    }
    if (dh < 0 && (Guint)-dh >= symHeight) {
      error(getPos(), "Bad delta-height value in JBIG2 symbol dictionary");
      goto syntaxError;
    }
    symHeight += dh;
    symWidth = 0;
    totalWidth = 0;
    j = i;

    // read the symbols in this height class
    while (1) {

      // read the delta width
      if (huff) {
	if (!huffDecoder->decodeInt(&dw, huffDWTable)) {
	  break;
	}
      } else {
	if (!arithDecoder->decodeInt(&dw, iadwStats)) {
	  break;
	}
      }
      if (dw < 0 && (Guint)-dw >= symWidth) {
	error(getPos(), "Bad delta-height value in JBIG2 symbol dictionary");
	goto syntaxError;
      }
      symWidth += dw;

      // using a collective bitmap, so don't read a bitmap here
      if (huff && !refAgg) {
	symWidths[i] = symWidth;
	totalWidth += symWidth;

      // refinement/aggregate coding
      } else if (refAgg) {
	if (huff) {
	  if (!huffDecoder->decodeInt(&refAggNum, huffAggInstTable)) {
	    break;
	  }
	} else {
	  if (!arithDecoder->decodeInt(&refAggNum, iaaiStats)) {
	    break;
	  }
	}
#if 0 //~ This special case was added about a year before the final draft
      //~ of the JBIG2 spec was released.  I have encountered some old
      //~ JBIG2 images that predate it.
	if (0) {
#else
	if (refAggNum == 1) {
#endif
	  if (huff) {
	    symID = huffDecoder->readBits(symCodeLen);
	    huffDecoder->decodeInt(&refDX, huffTableO);
	    huffDecoder->decodeInt(&refDY, huffTableO);
	    huffDecoder->decodeInt(&bmSize, huffTableA);
	    huffDecoder->reset();
	    arithDecoder->start();
	  } else {
	    symID = arithDecoder->decodeIAID(symCodeLen, iaidStats);
	    arithDecoder->decodeInt(&refDX, iardxStats);
	    arithDecoder->decodeInt(&refDY, iardyStats);
	  }
	  refBitmap = bitmaps[symID];
	  bitmaps[numInputSyms + i] =
	      readGenericRefinementRegion(symWidth, symHeight,
					  sdrTemplate, gFalse,
					  refBitmap, refDX, refDY,
					  sdrATX, sdrATY);
	  //~ do we need to use the bmSize value here (in Huffman mode)?
	} else {
	  bitmaps[numInputSyms + i] =
	      readTextRegion(huff, gTrue, symWidth, symHeight,
			     refAggNum, 0, numInputSyms + i, NULL,
			     symCodeLen, bitmaps, 0, 0, 0, 1, 0,
			     huffTableF, huffTableH, huffTableK, huffTableO,
			     huffTableO, huffTableO, huffTableO, huffTableA,
			     sdrTemplate, sdrATX, sdrATY);
	}

      // non-ref/agg coding
      } else {
	bitmaps[numInputSyms + i] =
	    readGenericBitmap(gFalse, symWidth, symHeight,
			      sdTemplate, gFalse, gFalse, NULL,
			      sdATX, sdATY, 0);
      }

      ++i;
    }

    // read the collective bitmap
    if (huff && !refAgg) {
      huffDecoder->decodeInt(&bmSize, huffBMSizeTable);
      huffDecoder->reset();
      if (bmSize == 0) {
	collBitmap = new JBIG2Bitmap(0, totalWidth, symHeight);
	bmSize = symHeight * ((totalWidth + 7) >> 3);
	p = collBitmap->getDataPtr();
	for (k = 0; k < (Guint)bmSize; ++k) {
	  *p++ = curStr->getChar();
	}
      } else {
	collBitmap = readGenericBitmap(gTrue, totalWidth, symHeight,
				       0, gFalse, gFalse, NULL, NULL, NULL,
				       bmSize);
      }
      x = 0;
      for (; j < i; ++j) {
	bitmaps[numInputSyms + j] =
	    collBitmap->getSlice(x, 0, symWidths[j], symHeight);
	x += symWidths[j];
      }
      delete collBitmap;
    }
  }

  // create the symbol dict object
  symbolDict = new JBIG2SymbolDict(segNum, numExSyms);

  // exported symbol list
  i = j = 0;
  ex = gFalse;
  while (i < numInputSyms + numNewSyms) {
    if (huff) {
      huffDecoder->decodeInt(&run, huffTableA);
    } else {
      arithDecoder->decodeInt(&run, iaexStats);
    }
    if (ex) {
      for (cnt = 0; cnt < run; ++cnt) {
	symbolDict->setBitmap(j++, bitmaps[i++]->copy());
      }
    } else {
      i += run;
    }
    ex = !ex;
  }

  for (i = 0; i < numNewSyms; ++i) {
    delete bitmaps[numInputSyms + i];
  }
  gfree(bitmaps);
  if (symWidths) {
    gfree(symWidths);
  }

  // save the arithmetic decoder stats
  if (!huff && contextRetained) {
    symbolDict->setGenericRegionStats(genericRegionStats->copy());
    if (refAgg) {
      symbolDict->setRefinementRegionStats(refinementRegionStats->copy());
    }
  }

  // store the new symbol dict
  segments->append(symbolDict);

  return gTrue;

 syntaxError:
  for (i = 0; i < numNewSyms; ++i) {
    if (bitmaps[numInputSyms + i]) {
      delete bitmaps[numInputSyms + i];
    }
  }
  gfree(bitmaps);
  if (symWidths) {
    gfree(symWidths);
  }
  return gFalse;

 eofError:
  error(getPos(), "Unexpected EOF in JBIG2 stream");
  return gFalse;
}

void JBIG2Stream::readTextRegionSeg(Guint segNum, GBool imm,
				    GBool lossless, Guint length,
				    Guint *refSegs, Guint nRefSegs) {
  JBIG2Bitmap *bitmap;
  JBIG2HuffmanTable runLengthTab[36];
  JBIG2HuffmanTable *symCodeTab;
  JBIG2HuffmanTable *huffFSTable, *huffDSTable, *huffDTTable;
  JBIG2HuffmanTable *huffRDWTable, *huffRDHTable;
  JBIG2HuffmanTable *huffRDXTable, *huffRDYTable, *huffRSizeTable;
  JBIG2Segment *seg;
  GList *codeTables;
  JBIG2SymbolDict *symbolDict;
  JBIG2Bitmap **syms;
  Guint w, h, x, y, segInfoFlags, extCombOp;
  Guint flags, huff, refine, logStrips, refCorner, transposed;
  Guint combOp, defPixel, templ;
  int sOffset;
  Guint huffFlags, huffFS, huffDS, huffDT;
  Guint huffRDW, huffRDH, huffRDX, huffRDY, huffRSize;
  Guint numInstances, numSyms, symCodeLen;
  int atx[2], aty[2];
  Guint i, k, kk;
  int j;

  // region segment info field
  if (!readULong(&w) || !readULong(&h) ||
      !readULong(&x) || !readULong(&y) ||
      !readUByte(&segInfoFlags)) {
    goto eofError;
  }
  extCombOp = segInfoFlags & 7;

  // rest of the text region header
  if (!readUWord(&flags)) {
    goto eofError;
  }
  huff = flags & 1;
  refine = (flags >> 1) & 1;
  logStrips = (flags >> 2) & 3;
  refCorner = (flags >> 4) & 3;
  transposed = (flags >> 6) & 1;
  combOp = (flags >> 7) & 3;
  defPixel = (flags >> 9) & 1;
  sOffset = (flags >> 10) & 0x1f;
  if (sOffset & 0x10) {
    sOffset |= -1 - 0x0f;
  }
  templ = (flags >> 15) & 1;
  huffFS = huffDS = huffDT = 0; // make gcc happy
  huffRDW = huffRDH = huffRDX = huffRDY = huffRSize = 0; // make gcc happy
  if (huff) {
    if (!readUWord(&huffFlags)) {
      goto eofError;
    }
    huffFS = huffFlags & 3;
    huffDS = (huffFlags >> 2) & 3;
    huffDT = (huffFlags >> 4) & 3;
    huffRDW = (huffFlags >> 6) & 3;
    huffRDH = (huffFlags >> 8) & 3;
    huffRDX = (huffFlags >> 10) & 3;
    huffRDY = (huffFlags >> 12) & 3;
    huffRSize = (huffFlags >> 14) & 1;
  }
  if (refine && templ == 0) {
    if (!readByte(&atx[0]) || !readByte(&aty[0]) ||
	!readByte(&atx[1]) || !readByte(&aty[1])) {
      goto eofError;
    }
  }
  if (!readULong(&numInstances)) {
    goto eofError;
  }

  // get symbol dictionaries and tables
  codeTables = new GList();
  numSyms = 0;
  for (i = 0; i < nRefSegs; ++i) {
    if ((seg = findSegment(refSegs[i]))) {
      if (seg->getType() == jbig2SegSymbolDict) {
	numSyms += ((JBIG2SymbolDict *)seg)->getSize();
      } else if (seg->getType() == jbig2SegCodeTable) {
	codeTables->append(seg);
      }
    } else {
      error(getPos(), "Invalid segment reference in JBIG2 text region");
    }
  }
  symCodeLen = 0;
  i = 1;
  while (i < numSyms) {
    ++symCodeLen;
    i <<= 1;
  }

  // get the symbol bitmaps
  syms = (JBIG2Bitmap **)gmallocn(numSyms, sizeof(JBIG2Bitmap *));
  kk = 0;
  for (i = 0; i < nRefSegs; ++i) {
    if ((seg = findSegment(refSegs[i]))) {
      if (seg->getType() == jbig2SegSymbolDict) {
	symbolDict = (JBIG2SymbolDict *)seg;
	for (k = 0; k < symbolDict->getSize(); ++k) {
	  syms[kk++] = symbolDict->getBitmap(k);
	}
      }
    }
  }

  // get the Huffman tables
  huffFSTable = huffDSTable = huffDTTable = NULL; // make gcc happy
  huffRDWTable = huffRDHTable = NULL; // make gcc happy
  huffRDXTable = huffRDYTable = huffRSizeTable = NULL; // make gcc happy
  i = 0;
  if (huff) {
    if (huffFS == 0) {
      huffFSTable = huffTableF;
    } else if (huffFS == 1) {
      huffFSTable = huffTableG;
    } else {
      huffFSTable = ((JBIG2CodeTable *)codeTables->get(i++))->getHuffTable();
    }
    if (huffDS == 0) {
      huffDSTable = huffTableH;
    } else if (huffDS == 1) {
      huffDSTable = huffTableI;
    } else if (huffDS == 2) {
      huffDSTable = huffTableJ;
    } else {
      huffDSTable = ((JBIG2CodeTable *)codeTables->get(i++))->getHuffTable();
    }
    if (huffDT == 0) {
      huffDTTable = huffTableK;
    } else if (huffDT == 1) {
      huffDTTable = huffTableL;
    } else if (huffDT == 2) {
      huffDTTable = huffTableM;
    } else {
      huffDTTable = ((JBIG2CodeTable *)codeTables->get(i++))->getHuffTable();
    }
    if (huffRDW == 0) {
      huffRDWTable = huffTableN;
    } else if (huffRDW == 1) {
      huffRDWTable = huffTableO;
    } else {
      huffRDWTable = ((JBIG2CodeTable *)codeTables->get(i++))->getHuffTable();
    }
    if (huffRDH == 0) {
      huffRDHTable = huffTableN;
    } else if (huffRDH == 1) {
      huffRDHTable = huffTableO;
    } else {
      huffRDHTable = ((JBIG2CodeTable *)codeTables->get(i++))->getHuffTable();
    }
    if (huffRDX == 0) {
      huffRDXTable = huffTableN;
    } else if (huffRDX == 1) {
      huffRDXTable = huffTableO;
    } else {
      huffRDXTable = ((JBIG2CodeTable *)codeTables->get(i++))->getHuffTable();
    }
    if (huffRDY == 0) {
      huffRDYTable = huffTableN;
    } else if (huffRDY == 1) {
      huffRDYTable = huffTableO;
    } else {
      huffRDYTable = ((JBIG2CodeTable *)codeTables->get(i++))->getHuffTable();
    }
    if (huffRSize == 0) {
      huffRSizeTable = huffTableA;
    } else {
      huffRSizeTable =
	  ((JBIG2CodeTable *)codeTables->get(i++))->getHuffTable();
    }
  }
  delete codeTables;

  // symbol ID Huffman decoding table
  if (huff) {
    huffDecoder->reset();
    for (i = 0; i < 32; ++i) {
      runLengthTab[i].val = i;
      runLengthTab[i].prefixLen = huffDecoder->readBits(4);
      runLengthTab[i].rangeLen = 0;
    }
    runLengthTab[32].val = 0x103;
    runLengthTab[32].prefixLen = huffDecoder->readBits(4);
    runLengthTab[32].rangeLen = 2;
    runLengthTab[33].val = 0x203;
    runLengthTab[33].prefixLen = huffDecoder->readBits(4);
    runLengthTab[33].rangeLen = 3;
    runLengthTab[34].val = 0x20b;
    runLengthTab[34].prefixLen = huffDecoder->readBits(4);
    runLengthTab[34].rangeLen = 7;
    runLengthTab[35].prefixLen = 0;
    runLengthTab[35].rangeLen = jbig2HuffmanEOT;
    huffDecoder->buildTable(runLengthTab, 35);
    symCodeTab = (JBIG2HuffmanTable *)gmallocn(numSyms + 1,
					       sizeof(JBIG2HuffmanTable));
    for (i = 0; i < numSyms; ++i) {
      symCodeTab[i].val = i;
      symCodeTab[i].rangeLen = 0;
    }
    i = 0;
    while (i < numSyms) {
      huffDecoder->decodeInt(&j, runLengthTab);
      if (j > 0x200) {
	for (j -= 0x200; j && i < numSyms; --j) {
	  symCodeTab[i++].prefixLen = 0;
	}
      } else if (j > 0x100) {
	for (j -= 0x100; j && i < numSyms; --j) {
	  symCodeTab[i].prefixLen = symCodeTab[i-1].prefixLen;
	  ++i;
	}
      } else {
	symCodeTab[i++].prefixLen = j;
      }
    }
    symCodeTab[numSyms].prefixLen = 0;
    symCodeTab[numSyms].rangeLen = jbig2HuffmanEOT;
    huffDecoder->buildTable(symCodeTab, numSyms);
    huffDecoder->reset();

  // set up the arithmetic decoder
  } else {
    symCodeTab = NULL;
    resetIntStats(symCodeLen);
    arithDecoder->start();
  }
  if (refine) {
    resetRefinementStats(templ, NULL);
  }

  bitmap = readTextRegion(huff, refine, w, h, numInstances,
			  logStrips, numSyms, symCodeTab, symCodeLen, syms,
			  defPixel, combOp, transposed, refCorner, sOffset,
			  huffFSTable, huffDSTable, huffDTTable,
			  huffRDWTable, huffRDHTable,
			  huffRDXTable, huffRDYTable, huffRSizeTable,
			  templ, atx, aty);

  gfree(syms);

  // combine the region bitmap into the page bitmap
  if (imm) {
    if (pageH == 0xffffffff && y + h > curPageH) {
      pageBitmap->expand(y + h, pageDefPixel);
    }
    pageBitmap->combine(bitmap, x, y, extCombOp);
    delete bitmap;

  // store the region bitmap
  } else {
    bitmap->setSegNum(segNum);
    segments->append(bitmap);
  }

  // clean up the Huffman decoder
  if (huff) {
    gfree(symCodeTab);
  }

  return;

 eofError:
  error(getPos(), "Unexpected EOF in JBIG2 stream");
}

JBIG2Bitmap *JBIG2Stream::readTextRegion(GBool huff, GBool refine,
					 int w, int h,
					 Guint numInstances,
					 Guint logStrips,
					 int numSyms,
					 JBIG2HuffmanTable *symCodeTab,
					 Guint symCodeLen,
					 JBIG2Bitmap **syms,
					 Guint defPixel, Guint combOp,
					 Guint transposed, Guint refCorner,
					 int sOffset,
					 JBIG2HuffmanTable *huffFSTable,
					 JBIG2HuffmanTable *huffDSTable,
					 JBIG2HuffmanTable *huffDTTable,
					 JBIG2HuffmanTable *huffRDWTable,
					 JBIG2HuffmanTable *huffRDHTable,
					 JBIG2HuffmanTable *huffRDXTable,
					 JBIG2HuffmanTable *huffRDYTable,