pdftops/XRef.h

   1 //========================================================================
   2 //
   3 // XRef.h
   4 //
   5 // Copyright 1996-2003 Glyph & Cog, LLC
   6 //
   7 //========================================================================
   8
   9 #ifndef XREF_H
  10 #define XREF_H
  11
  12 #include <config.h>
  13
  14 #ifdef USE_GCC_PRAGMAS
  15 #pragma interface
  16 #endif
  17
  18 #include "gtypes.h"
  19 #include "Object.h"
  20
  21 class Dict;
  22 class Stream;
  23 class Parser;
  24 class ObjectStream;
  25
  26 //------------------------------------------------------------------------
  27 // XRef
  28 //------------------------------------------------------------------------
  29
  30 enum XRefEntryType {
  31   xrefEntryFree,
  32   xrefEntryUncompressed,
  33   xrefEntryCompressed
  34 };
  35
  36 struct XRefEntry {
  37   Guint offset;
  38   int gen;
  39   XRefEntryType type;
  40 };
  41
  42 class XRef {
  43 public:
  44
  45   // Constructor.  Read xref table from stream.
  46   XRef(BaseStream *strA);
  47
  48   // Destructor.
  49   ~XRef();
  50
  51   // Is xref table valid?
  52   GBool isOk() { return ok; }
  53
  54   // Get the error code (if isOk() returns false).
  55   int getErrorCode() { return errCode; }
  56
  57   // Set the encryption parameters.
  58   void setEncryption(int permFlagsA, GBool ownerPasswordOkA,
  59                      Guchar *fileKeyA, int keyLengthA, int encVersionA);
  60
  61   // Is the file encrypted?
  62   GBool isEncrypted() { return encrypted; }
  63
  64   // Check various permissions.
  65   GBool okToPrint(GBool ignoreOwnerPW = gFalse);
  66   GBool okToChange(GBool ignoreOwnerPW = gFalse);
  67   GBool okToCopy(GBool ignoreOwnerPW = gFalse);
  68   GBool okToAddNotes(GBool ignoreOwnerPW = gFalse);
  69
  70   // Get catalog object.
  71   Object *getCatalog(Object *obj) { return fetch(rootNum, rootGen, obj); }
  72
  73   // Fetch an indirect reference.
  74   Object *fetch(int num, int gen, Object *obj);
  75
  76   // Return the document's Info dictionary (if any).
  77   Object *getDocInfo(Object *obj);
  78   Object *getDocInfoNF(Object *obj);
  79
  80   // Return the number of objects in the xref table.
  81   int getNumObjects() { return size; }
  82
  83   // Return the offset of the last xref table.
  84   Guint getLastXRefPos() { return lastXRefPos; }
  85
  86   // Return the catalog object reference.
  87   int getRootNum() { return rootNum; }
  88   int getRootGen() { return rootGen; }
  89
  90   // Get end position for a stream in a damaged file.
  91   // Returns false if unknown or file is not damaged.
  92   GBool getStreamEnd(Guint streamStart, Guint *streamEnd);
  93
  94   // Direct access.
  95   int getSize() { return size; }
  96   XRefEntry *getEntry(int i) { return &entries[i]; }
  97   Object *getTrailerDict() { return &trailerDict; }
  98
  99 private:
 100
 101   BaseStream *str;              // input stream
 102   Guint start;                  // offset in file (to allow for garbage
 103                                 //   at beginning of file)
 104   XRefEntry *entries;           // xref entries
 105   int size;                     // size of <entries> array
 106   int rootNum, rootGen;         // catalog dict
 107   GBool ok;                     // true if xref table is valid
 108   int errCode;                  // error code (if <ok> is false)
 109   Object trailerDict;           // trailer dictionary
 110   Guint lastXRefPos;            // offset of last xref table
 111   Guint *streamEnds;            // 'endstream' positions - only used in
 112                                 //   damaged files
 113   int streamEndsLen;            // number of valid entries in streamEnds
 114   ObjectStream *objStr;         // cached object stream
 115   GBool encrypted;              // true if file is encrypted
 116   int permFlags;                // permission bits
 117   GBool ownerPasswordOk;        // true if owner password is correct
 118   Guchar fileKey[16];           // file decryption key
 119   int keyLength;                // length of key, in bytes
 120   int encVersion;               // encryption algorithm
 121
 122   Guint getStartXref();
 123   GBool readXRef(Guint *pos);
 124   GBool readXRefTable(Parser *parser, Guint *pos);
 125   GBool readXRefStreamSection(Stream *xrefStr, int *w, int first, int n);
 126   GBool readXRefStream(Stream *xrefStr, Guint *pos);
 127   GBool constructXRef();
 128   Guint strToUnsigned(char *s);
 129 };
 130
 131 #endif