/** read reference table from file so we can locate objects in pdf file and read the trailers */
private PdfObject readLegacyReferenceTable(
PdfObject rootObj, int pointer, final int eof, final PdfFileReader currentPdfFile)
throws PdfException {
int endTable, current = 0; // current object number
byte[] Bytes;
int bufSize = 1024;
/** read and decode 1 or more trailers */
while (true) {
try {
// allow for pointer outside file
Bytes = Trailer.readTrailer(bufSize, pointer, eof, pdf_datafile);
} catch (final Exception e) {
try {
closeFile();
} catch (final IOException e1) {
if (LogWriter.isOutput()) {
LogWriter.writeLog("Exception " + e + " closing file " + e1);
}
}
throw new PdfException("Exception " + e + " reading trailer");
}
if (Bytes == null) // safety catch
{
break;
}
/** get trailer */
int i = 0;
final int maxLen = Bytes.length;
// for(int a=0;a<100;a++)
// System.out.println((char)Bytes[i+a]);
while (i < maxLen) { // look for trailer keyword
if (Bytes[i] == 116
&& Bytes[i + 1] == 114
&& Bytes[i + 2] == 97
&& Bytes[i + 3] == 105
&& Bytes[i + 4] == 108
&& Bytes[i + 5] == 101
&& Bytes[i + 6] == 114) {
break;
}
i++;
}
// save endtable position for later
endTable = i;
if (i == Bytes.length) {
break;
}
// move to beyond <<
while (Bytes[i] != 60 && Bytes[i - 1] != 60) {
i++;
}
i++;
final PdfObject pdfObject = new CompressedObject("1 0 R");
Dictionary.readDictionary(pdfObject, i, Bytes, -1, true, currentPdfFile, false);
// move to beyond >>
int level = 0;
while (true) {
if (Bytes[i] == 60 && Bytes[i - 1] == 60) {
level++;
i++;
} else if (Bytes[i] == '[') {
i++;
while (Bytes[i] != ']') {
i++;
if (i == Bytes.length) {
break;
}
}
} else if (Bytes[i] == 62 && Bytes[i - 1] == 62) {
level--;
i++;
}
if (level == 0) {
break;
}
i++;
}
// handle optional XRefStm
final int XRefStm = pdfObject.getInt(PdfDictionary.XRefStm);
if (XRefStm != -1) {
pointer = XRefStm;
} else { // usual way
boolean hasRef = true;
/** handle spaces and comments */
while (Bytes[i] == 10 || Bytes[i] == 13) {
i++;
}
while (Bytes[i] == '%') {
while (Bytes[i] != 10) {
i++;
}
i++;
}
/* fix for /Users/markee/Downloads/oneiderapartnerbrochure_web_1371798737.pdf
/**/
// look for xref as end of startref
while (Bytes[i] != 116
&& Bytes[i + 1] != 120
&& Bytes[i + 2] != 114
&& Bytes[i + 3] != 101
&& Bytes[i + 4] != 102) {
if (Bytes[i] == 'o' && Bytes[i + 1] == 'b' && Bytes[i + 2] == 'j') {
hasRef = false;
break;
}
i++;
}
if (hasRef) {
i += 8;
// move to start of value ignoring spaces or returns
while ((i < maxLen) && (Bytes[i] == 10 || Bytes[i] == 32 || Bytes[i] == 13)) {
i++;
}
final int s = i;
// allow for characters between xref and startref
while (i < maxLen && Bytes[i] != 10 && Bytes[i] != 32 && Bytes[i] != 13) {
i++;
}
/** convert xref to string to get pointer */
if (s != i) {
pointer = NumberUtils.parseInt(s, i, Bytes);
}
}
}
i = 0;
// allow for bum data at start
while (Bytes[i] == 13 || Bytes[i] == 10 || Bytes[i] == 9) {
i++;
}
if (pointer == -1) {
if (LogWriter.isOutput()) {
LogWriter.writeLog("No startRef");
}
/** now read the objects for the trailers */
} else if (Bytes[i] == 120
&& Bytes[i + 1] == 114
&& Bytes[i + 2] == 101
&& Bytes[i + 3] == 102) { // make sure starts xref
i = 5;
// move to start of value ignoring spaces or returns
while (Bytes[i] == 10 || Bytes[i] == 32 || Bytes[i] == 13) {
i++;
}
current = offset.readXRefs(current, Bytes, endTable, i, eof, pdf_datafile);
/**
* now process trailer values - only first set of table values for root, encryption and info
*/
if (rootObj == null) {
rootObj = pdfObject.getDictionary(PdfDictionary.Root);
encryptObj = pdfObject.getDictionary(PdfDictionary.Encrypt);
if (encryptObj != null) {
final byte[][] IDs = pdfObject.getStringArray(PdfDictionary.ID);
if (IDs != null && this.ID == null) {
// only the first encountered ID should be used as a fileID for decryption
this.ID = IDs[0];
}
}
infoObject = pdfObject.getDictionary(PdfDictionary.Info);
}
// make sure first values used if several tables and code for prev
pointer = pdfObject.getInt(PdfDictionary.Prev);
// see if other trailers
if (pointer != -1 && pointer < this.eof) {
// reset values for loop
bufSize = 1024;
// track ref table so we can work out object length
offset.addXref(pointer);
} else // reset if fails second test above
{
pointer = -1;
}
} else {
pointer = -1;
// needs to be read to pick up potential /Pages value
//noinspection ObjectAllocationInLoop
rootObj = new PageObject(BrokenRefTable.findOffsets(pdf_datafile, offset));
currentPdfFile.readObject(rootObj);
offset.setRefTableInvalid(true);
}
if (pointer == -1) {
break;
}
}
if (encryptObj == null
&& rootObj != null) { // manual check for broken file (ignore if Encrypted)
int type = -1;
int status = rootObj.getStatus();
byte[] data = rootObj.getUnresolvedData();
try {
final ObjectDecoder objectDecoder = new ObjectDecoder(currentPdfFile);
objectDecoder.checkResolved(rootObj);
type = rootObj.getParameterConstant(PdfDictionary.Type);
} catch (Exception e) { // we need to ignore so just catch, put back as was and log
rootObj.setStatus(status);
rootObj.setUnresolvedData(data, status);
if (LogWriter.isOutput()) {
LogWriter.writeLog("[PDF] Exception reading type on root object " + e);
}
}
// something gone wrong so manually index
if (type == PdfDictionary.Font) { // see 21153 - ref table in wrong order
rootObj = null; // /will reset in code at end
}
}
// something gone wrong so manually index
if (rootObj == null) { // see 21382
offset.clear();
offset.reuse();
// needs to be read to pick up potential /Pages value
//noinspection ObjectAllocationInLoop
rootObj = new PageObject(BrokenRefTable.findOffsets(pdf_datafile, offset));
currentPdfFile.readObject(rootObj);
offset.setRefTableInvalid(true);
}
return rootObj;
}
/** read first start ref from last 1024 bytes */
private int readFirstStartRef() throws PdfException {
// reset flag
offset.setRefTableInvalid(false);
int pointer = -1;
int i = 1019;
final StringBuilder startRef = new StringBuilder(10);
/** move to end of file and read last 1024 bytes */
final int block = 1024;
byte[] lastBytes = new byte[block];
long end;
/** set endpoint, losing null chars and anything before EOF */
final int[] EndOfFileMarker = {37, 37, 69, 79};
int valReached = 3;
boolean EOFFound = false;
try {
end = eof;
/** lose nulls and other trash from end of file */
final int bufSize = 255;
while (true) {
final byte[] buffer = getBytes(end - bufSize, bufSize);
int offset = 0;
for (int ii = bufSize - 1; ii > -1; ii--) {
// see if we can decrement EOF tracker or restart check
if (!EOFFound) {
valReached = 3;
}
if (buffer[ii] == EndOfFileMarker[valReached]) {
valReached--;
EOFFound = true;
} else {
EOFFound = false;
}
// move to next byte
offset--;
if (valReached < 0) {
ii = -1;
}
}
// exit if found values on loop
if (valReached < 0) {
end -= offset;
break;
} else {
end -= bufSize;
}
// allow for no eof
if (end < 0) {
end = eof;
break;
}
}
// end=end+bufSize;
// allow for very small file
int count = (int) (end - block);
if (count < 0) {
count = 0;
final int size = (int) eof;
lastBytes = new byte[size];
i = size + 3; // force reset below
}
lastBytes = getBytes(count, lastBytes.length);
} catch (final Exception e) {
if (LogWriter.isOutput()) {
LogWriter.writeLog("Exception " + e + " reading last 1024 bytes");
}
throw new PdfException(e + " reading last 1024 bytes");
}
// for(int ii=0;ii<lastBytes.length;ii++){
// System.out.print((char)lastBytes[ii]);
// }
// System.out.println();
// look for tref as end of startxref
final int fileSize = lastBytes.length;
if (i > fileSize) {
i = fileSize - 5;
}
while (i > -1) {
// first check is because startref works as well a startxref !!
if (((lastBytes[i] == 116 && lastBytes[i + 1] == 120)
|| (lastBytes[i] == 114 && lastBytes[i + 1] == 116))
&& (lastBytes[i + 2] == 114)
&& (lastBytes[i + 3] == 101)
&& (lastBytes[i + 4] == 102)) {
break;
}
i--;
}
/** trap buggy files */
if (i == -1) {
try {
closeFile();
} catch (final IOException e1) {
if (LogWriter.isOutput()) {
LogWriter.writeLog("Exception " + e1 + " closing file");
}
}
throw new PdfException("No Startxref found in last 1024 bytes ");
}
i += 5; // allow for word length
// move to start of value ignoring spaces or returns
while (i < 1024 && (lastBytes[i] == 10 || lastBytes[i] == 32 || lastBytes[i] == 13)) {
i++;
}
// move to start of value ignoring spaces or returns
while ((i < 1024) && (lastBytes[i] != 10) && (lastBytes[i] != 32) && (lastBytes[i] != 13)) {
startRef.append((char) lastBytes[i]);
i++;
}
/** convert xref to string to get pointer */
if (startRef.length() > 0) {
pointer = Integer.parseInt(startRef.toString());
}
if (pointer == -1) {
if (LogWriter.isOutput()) {
LogWriter.writeLog("No Startref found in last 1024 bytes ");
}
try {
closeFile();
} catch (final IOException e1) {
if (LogWriter.isOutput()) {
LogWriter.writeLog("Exception " + e1 + " closing file");
}
}
throw new PdfException("No Startref found in last 1024 bytes ");
}
return pointer;
}
/**
* read reference table start to see if new 1.5 type or traditional xref
*
* @throws PdfException
*/
public final PdfObject readReferenceTable(
final PdfObject linearObj,
final PdfFileReader currentPdfFile,
final ObjectReader objectReader)
throws PdfException {
int pointer = -1;
final int eof = (int) this.eof;
boolean islinearizedCompressed = false;
if (linearObj == null) {
pointer = readFirstStartRef();
} else { // find at start of Linearized
final byte[] data = pdf_datafile.getPdfBuffer();
final int count = data.length;
int ptr = 5;
for (int i = 0; i < count; i++) {
// track start of this object (needed for compressed)
if (data[i] == 'e'
&& data[i + 1] == 'n'
&& data[i + 2] == 'd'
&& data[i + 3] == 'o'
&& data[i + 4] == 'b'
&& data[i + 5] == 'j') {
ptr = i + 6;
}
if (data[i] == 'x' && data[i + 1] == 'r' && data[i + 2] == 'e' && data[i + 3] == 'f') {
pointer = i;
i = count;
} else if (data[i] == 'X'
&& data[i + 1] == 'R'
&& data[i + 2] == 'e'
&& data[i + 3] == 'f') {
islinearizedCompressed = true;
pointer = ptr;
while (data[pointer] == 10 || data[pointer] == 13 || data[pointer] == 32) {
pointer++;
}
i = count;
}
}
}
offset.addXref(pointer);
PdfObject rootObj = null;
if (pointer >= eof || pointer == 0) {
if (LogWriter.isOutput()) {
LogWriter.writeLog("Pointer not if file - trying to manually find startref");
}
offset.setRefTableInvalid(true);
try {
rootObj = new PageObject(BrokenRefTable.findOffsets(pdf_datafile, offset));
} catch (Error err) {
throw new PdfException(err.getMessage() + " attempting to manually scan file for objects");
}
currentPdfFile.readObject(rootObj);
return rootObj;
} else if (islinearizedCompressed || isCompressedStream(pointer, eof)) {
return readCompressedStream(rootObj, pointer, currentPdfFile, objectReader, linearObj);
} else {
return readLegacyReferenceTable(rootObj, pointer, eof, currentPdfFile);
}
}