XRef.h

//========================================================================
//
// XRef.h
//
// Copyright 1996-2002 Glyph & Cog, LLC
//
//========================================================================
 
#ifndef XREF_H
#define XREF_H
 
#include <aconf.h>
 
#ifdef USE_GCC_PRAGMAS
#pragma interface
#endif
 
#include "gtypes.h"
#include "Object.h"
 
class Dict;
class Stream;
 
//------------------------------------------------------------------------
// XRef
//------------------------------------------------------------------------
 
struct XRefEntry {
  Guint offset;
  int gen;
  GBool used;
};
 
class XRef {
public:
 
  // Constructor.  Read xref table from stream.
  XRef(BaseStream *strA, GString *ownerPassword, GString *userPassword);
 
  // Destructor.
  ~XRef();
 
  // Is xref table valid?
  GBool isOk() { return ok; }
 
  // Get the error code (if isOk() returns false).
  int getErrorCode() { return errCode; }
 
  // Is the file encrypted?
#ifndef NO_DECRYPTION
  GBool isEncrypted() { return encrypted; }
#else
  GBool isEncrypted() { return gFalse; }
#endif
 
  // Check various permissions.
  GBool okToPrint(GBool ignoreOwnerPW = gFalse);
  GBool okToChange(GBool ignoreOwnerPW = gFalse);
  GBool okToCopy(GBool ignoreOwnerPW = gFalse);
  GBool okToAddNotes(GBool ignoreOwnerPW = gFalse);
 
  // Get catalog object.
  Object *getCatalog(Object *obj) { return fetch(rootNum, rootGen, obj); }
 
  // Fetch an indirect reference.
  Object *fetch(int num, int gen, Object *obj);
 
  // Return the document's Info dictionary (if any).
  Object *getDocInfo(Object *obj);
  Object *getDocInfoNF(Object *obj);
 
  // Return the number of objects in the xref table.
  int getNumObjects() { return size; }
 
  // Return the offset of the last xref table.
  Guint getLastXRefPos() { return lastXRefPos; }
 
  // Return the catalog object reference.
  int getRootNum() { return rootNum; }
  int getRootGen() { return rootGen; }
 
  // Get end position for a stream in a damaged file.
  // Returns false if unknown or file is not damaged.
  GBool getStreamEnd(Guint streamStart, Guint *streamEnd);
 
  // Direct access.
  int getSize() { return size; }
  XRefEntry *getEntry(int i) { return &entries[i]; }
  Object *getTrailerDict() { return &trailerDict; }
 
private:
 
  BaseStream *str;      // input stream
  Guint start;          // offset in file (to allow for garbage
                //   at beginning of file)
  XRefEntry *entries;       // xref entries
  int size;         // size of <entries> array
  int rootNum, rootGen;     // catalog dict
  GBool ok;         // true if xref table is valid
  int errCode;          // error code (if <ok> is false)
  Object trailerDict;       // trailer dictionary
  Guint lastXRefPos;        // offset of last xref table
  Guint *streamEnds;        // 'endstream' positions - only used in
                //   damaged files
  int streamEndsLen;        // number of valid entries in streamEnds
#ifndef NO_DECRYPTION
  GBool encrypted;      // true if file is encrypted
  int encVersion;       // encryption algorithm
  int encRevision;      // security handler revision
  int keyLength;        // length of key, in bytes
  int permFlags;        // permission bits
  Guchar fileKey[16];       // file decryption key
  GBool ownerPasswordOk;    // true if owner password is correct
#endif
 
  Guint readTrailer();
  GBool readXRef(Guint *pos);
  GBool constructXRef();
  GBool checkEncrypted(GString *ownerPassword, GString *userPassword);
  Guint strToUnsigned(char *s);
};
 
#endif