+++ /dev/null
-//========================================================================
-//
-// XRef.cc
-//
-// Copyright 1996-2003 Glyph & Cog, LLC
-//
-//========================================================================
-
-#include <aconf.h>
-
-#ifdef USE_GCC_PRAGMAS
-#pragma implementation
-#endif
-
-#include <stdlib.h>
-#include <stddef.h>
-#include <string.h>
-#include <ctype.h>
-#include "gmem.h"
-#include "Object.h"
-#include "Stream.h"
-#include "Lexer.h"
-#include "Parser.h"
-#include "Dict.h"
-#include "Error.h"
-#include "ErrorCodes.h"
-#include "XRef.h"
-
-//------------------------------------------------------------------------
-
-#define xrefSearchSize 1024 // read this many bytes at end of file
- // to look for 'startxref'
-
-//------------------------------------------------------------------------
-// Permission bits
-//------------------------------------------------------------------------
-
-#define permPrint (1<<2)
-#define permChange (1<<3)
-#define permCopy (1<<4)
-#define permNotes (1<<5)
-#define defPermFlags 0xfffc
-
-//------------------------------------------------------------------------
-// ObjectStream
-//------------------------------------------------------------------------
-
-class ObjectStream {
-public:
-
- // Create an object stream, using object number <objStrNum>,
- // generation 0.
- ObjectStream(XRef *xref, int objStrNumA);
-
- ~ObjectStream();
-
- // Return the object number of this object stream.
- int getObjStrNum() { return objStrNum; }
-
- // Get the <objIdx>th object from this stream, which should be
- // object number <objNum>, generation 0.
- Object *getObject(int objIdx, int objNum, Object *obj);
-
-private:
-
- int objStrNum; // object number of the object stream
- int nObjects; // number of objects in the stream
- Object *objs; // the objects (length = nObjects)
- int *objNums; // the object numbers (length = nObjects)
-};
-
-ObjectStream::ObjectStream(XRef *xref, int objStrNumA) {
- Stream *str;
- Parser *parser;
- int *offsets;
- Object objStr, obj1, obj2;
- int first, i;
-
- objStrNum = objStrNumA;
- nObjects = 0;
- objs = NULL;
- objNums = NULL;
-
- if (!xref->fetch(objStrNum, 0, &objStr)->isStream()) {
- goto err1;
- }
-
- if (!objStr.streamGetDict()->lookup("N", &obj1)->isInt()) {
- obj1.free();
- goto err1;
- }
- nObjects = obj1.getInt();
- obj1.free();
- if (nObjects <= 0) {
- goto err1;
- }
-
- if (!objStr.streamGetDict()->lookup("First", &obj1)->isInt()) {
- obj1.free();
- goto err1;
- }
- first = obj1.getInt();
- obj1.free();
- if (first < 0) {
- goto err1;
- }
-
- objs = new Object[nObjects];
- objNums = (int *)gmallocn(nObjects, sizeof(int));
- offsets = (int *)gmallocn(nObjects, sizeof(int));
-
- // parse the header: object numbers and offsets
- objStr.streamReset();
- obj1.initNull();
- str = new EmbedStream(objStr.getStream(), &obj1, gTrue, first);
- parser = new Parser(xref, new Lexer(xref, str));
- for (i = 0; i < nObjects; ++i) {
- parser->getObj(&obj1);
- parser->getObj(&obj2);
- if (!obj1.isInt() || !obj2.isInt()) {
- obj1.free();
- obj2.free();
- delete parser;
- gfree(offsets);
- goto err1;
- }
- objNums[i] = obj1.getInt();
- offsets[i] = obj2.getInt();
- obj1.free();
- obj2.free();
- if (objNums[i] < 0 || offsets[i] < 0 ||
- (i > 0 && offsets[i] < offsets[i-1])) {
- delete parser;
- gfree(offsets);
- goto err1;
- }
- }
- while (str->getChar() != EOF) ;
- delete parser;
-
- // skip to the first object - this shouldn't be necessary because
- // the First key is supposed to be equal to offsets[0], but just in
- // case...
- for (i = first; i < offsets[0]; ++i) {
- objStr.getStream()->getChar();
- }
-
- // parse the objects
- for (i = 0; i < nObjects; ++i) {
- obj1.initNull();
- if (i == nObjects - 1) {
- str = new EmbedStream(objStr.getStream(), &obj1, gFalse, 0);
- } else {
- str = new EmbedStream(objStr.getStream(), &obj1, gTrue,
- offsets[i+1] - offsets[i]);
- }
- parser = new Parser(xref, new Lexer(xref, str));
- parser->getObj(&objs[i]);
- while (str->getChar() != EOF) ;
- delete parser;
- }
-
- gfree(offsets);
-
- err1:
- objStr.free();
- return;
-}
-
-ObjectStream::~ObjectStream() {
- int i;
-
- if (objs) {
- for (i = 0; i < nObjects; ++i) {
- objs[i].free();
- }
- delete[] objs;
- }
- gfree(objNums);
-}
-
-Object *ObjectStream::getObject(int objIdx, int objNum, Object *obj) {
- if (objIdx < 0 || objIdx >= nObjects || objNum != objNums[objIdx]) {
- return obj->initNull();
- }
- return objs[objIdx].copy(obj);
-}
-
-//------------------------------------------------------------------------
-// XRef
-//------------------------------------------------------------------------
-
-XRef::XRef(BaseStream *strA) {
- Guint pos;
- Object obj;
-
- ok = gTrue;
- errCode = errNone;
- size = 0;
- entries = NULL;
- streamEnds = NULL;
- streamEndsLen = 0;
- objStr = NULL;
-
- encrypted = gFalse;
- permFlags = defPermFlags;
- ownerPasswordOk = gFalse;
-
- // read the trailer
- str = strA;
- start = str->getStart();
- pos = getStartXref();
-
- // if there was a problem with the 'startxref' position, try to
- // reconstruct the xref table
- if (pos == 0) {
- if (!(ok = constructXRef())) {
- errCode = errDamaged;
- return;
- }
-
- // read the xref table
- } else {
- while (readXRef(&pos)) ;
-
- // if there was a problem with the xref table,
- // try to reconstruct it
- if (!ok) {
- if (!(ok = constructXRef())) {
- errCode = errDamaged;
- return;
- }
- }
- }
-
- // get the root dictionary (catalog) object
- trailerDict.dictLookupNF("Root", &obj);
- if (obj.isRef()) {
- rootNum = obj.getRefNum();
- rootGen = obj.getRefGen();
- obj.free();
- } else {
- obj.free();
- if (!(ok = constructXRef())) {
- errCode = errDamaged;
- return;
- }
- }
-
- // now set the trailer dictionary's xref pointer so we can fetch
- // indirect objects from it
- trailerDict.getDict()->setXRef(this);
-}
-
-XRef::~XRef() {
- gfree(entries);
- trailerDict.free();
- if (streamEnds) {
- gfree(streamEnds);
- }
- if (objStr) {
- delete objStr;
- }
-}
-
-// Read the 'startxref' position.
-Guint XRef::getStartXref() {
- char buf[xrefSearchSize+1];
- char *p;
- int c, n, i;
-
- // read last xrefSearchSize bytes
- str->setPos(xrefSearchSize, -1);
- for (n = 0; n < xrefSearchSize; ++n) {
- if ((c = str->getChar()) == EOF) {
- break;
- }
- buf[n] = c;
- }
- buf[n] = '\0';
-
- // find startxref
- for (i = n - 9; i >= 0; --i) {
- if (!strncmp(&buf[i], "startxref", 9)) {
- break;
- }
- }
- if (i < 0) {
- return 0;
- }
- for (p = &buf[i+9]; isspace(*p); ++p) ;
- lastXRefPos = strToUnsigned(p);
-
- return lastXRefPos;
-}
-
-// Read one xref table section. Also reads the associated trailer
-// dictionary, and returns the prev pointer (if any).
-GBool XRef::readXRef(Guint *pos) {
- Parser *parser;
- Object obj;
- GBool more;
-
- // start up a parser, parse one token
- obj.initNull();
- parser = new Parser(NULL,
- new Lexer(NULL,
- str->makeSubStream(start + *pos, gFalse, 0, &obj)));
- parser->getObj(&obj);
-
- // parse an old-style xref table
- if (obj.isCmd("xref")) {
- obj.free();
- more = readXRefTable(parser, pos);
-
- // parse an xref stream
- } else if (obj.isInt()) {
- obj.free();
- if (!parser->getObj(&obj)->isInt()) {
- goto err1;
- }
- obj.free();
- if (!parser->getObj(&obj)->isCmd("obj")) {
- goto err1;
- }
- obj.free();
- if (!parser->getObj(&obj)->isStream()) {
- goto err1;
- }
- more = readXRefStream(obj.getStream(), pos);
- obj.free();
-
- } else {
- goto err1;
- }
-
- delete parser;
- return more;
-
- err1:
- obj.free();
- delete parser;
- ok = gFalse;
- return gFalse;
-}
-
-GBool XRef::readXRefTable(Parser *parser, Guint *pos) {
- XRefEntry entry;
- GBool more;
- Object obj, obj2;
- Guint pos2;
- int first, n, newSize, i;
-
- while (1) {
- parser->getObj(&obj);
- if (obj.isCmd("trailer")) {
- obj.free();
- break;
- }
- if (!obj.isInt()) {
- goto err1;
- }
- first = obj.getInt();
- obj.free();
- if (!parser->getObj(&obj)->isInt()) {
- goto err1;
- }
- n = obj.getInt();
- obj.free();
- if (first < 0 || n < 0 || first + n < 0) {
- goto err1;
- }
- if (first + n > size) {
- for (newSize = size ? 2 * size : 1024;
- first + n > newSize && newSize > 0;
- newSize <<= 1) ;
- if (newSize < 0) {
- goto err1;
- }
- entries = (XRefEntry *)greallocn(entries, newSize, sizeof(XRefEntry));
- for (i = size; i < newSize; ++i) {
- entries[i].offset = 0xffffffff;
- entries[i].type = xrefEntryFree;
- }
- size = newSize;
- }
- for (i = first; i < first + n; ++i) {
- if (!parser->getObj(&obj)->isInt()) {
- goto err1;
- }
- entry.offset = (Guint)obj.getInt();
- obj.free();
- if (!parser->getObj(&obj)->isInt()) {
- goto err1;
- }
- entry.gen = obj.getInt();
- obj.free();
- parser->getObj(&obj);
- if (obj.isCmd("n")) {
- entry.type = xrefEntryUncompressed;
- } else if (obj.isCmd("f")) {
- entry.type = xrefEntryFree;
- } else {
- goto err1;
- }
- obj.free();
- if (entries[i].offset == 0xffffffff) {
- entries[i] = entry;
- // PDF files of patents from the IBM Intellectual Property
- // Network have a bug: the xref table claims to start at 1
- // instead of 0.
- if (i == 1 && first == 1 &&
- entries[1].offset == 0 && entries[1].gen == 65535 &&
- entries[1].type == xrefEntryFree) {
- i = first = 0;
- entries[0] = entries[1];
- entries[1].offset = 0xffffffff;
- }
- }
- }
- }
-
- // read the trailer dictionary
- if (!parser->getObj(&obj)->isDict()) {
- goto err1;
- }
-
- // get the 'Prev' pointer
- obj.getDict()->lookupNF("Prev", &obj2);
- if (obj2.isInt()) {
- *pos = (Guint)obj2.getInt();
- more = gTrue;
- } else if (obj2.isRef()) {
- // certain buggy PDF generators generate "/Prev NNN 0 R" instead
- // of "/Prev NNN"
- *pos = (Guint)obj2.getRefNum();
- more = gTrue;
- } else {
- more = gFalse;
- }
- obj2.free();
-
- // save the first trailer dictionary
- if (trailerDict.isNone()) {
- obj.copy(&trailerDict);
- }
-
- // check for an 'XRefStm' key
- if (obj.getDict()->lookup("XRefStm", &obj2)->isInt()) {
- pos2 = (Guint)obj2.getInt();
- readXRef(&pos2);
- if (!ok) {
- obj2.free();
- goto err1;
- }
- }
- obj2.free();
-
- obj.free();
- return more;
-
- err1:
- obj.free();
- ok = gFalse;
- return gFalse;
-}
-
-GBool XRef::readXRefStream(Stream *xrefStr, Guint *pos) {
- Dict *dict;
- int w[3];
- GBool more;
- Object obj, obj2, idx;
- int newSize, first, n, i;
-
- dict = xrefStr->getDict();
-
- if (!dict->lookupNF("Size", &obj)->isInt()) {
- goto err1;
- }
- newSize = obj.getInt();
- obj.free();
- if (newSize < 0) {
- goto err1;
- }
- if (newSize > size) {
- entries = (XRefEntry *)greallocn(entries, newSize, sizeof(XRefEntry));
- for (i = size; i < newSize; ++i) {
- entries[i].offset = 0xffffffff;
- entries[i].type = xrefEntryFree;
- }
- size = newSize;
- }
-
- if (!dict->lookupNF("W", &obj)->isArray() ||
- obj.arrayGetLength() < 3) {
- goto err1;
- }
- for (i = 0; i < 3; ++i) {
- if (!obj.arrayGet(i, &obj2)->isInt()) {
- obj2.free();
- goto err1;
- }
- w[i] = obj2.getInt();
- obj2.free();
- if (w[i] < 0 || w[i] > 4) {
- goto err1;
- }
- }
- obj.free();
-
- xrefStr->reset();
- dict->lookupNF("Index", &idx);
- if (idx.isArray()) {
- for (i = 0; i+1 < idx.arrayGetLength(); i += 2) {
- if (!idx.arrayGet(i, &obj)->isInt()) {
- idx.free();
- goto err1;
- }
- first = obj.getInt();
- obj.free();
- if (!idx.arrayGet(i+1, &obj)->isInt()) {
- idx.free();
- goto err1;
- }
- n = obj.getInt();
- obj.free();
- if (first < 0 || n < 0 ||
- !readXRefStreamSection(xrefStr, w, first, n)) {
- idx.free();
- goto err0;
- }
- }
- } else {
- if (!readXRefStreamSection(xrefStr, w, 0, newSize)) {
- idx.free();
- goto err0;
- }
- }
- idx.free();
-
- dict->lookupNF("Prev", &obj);
- if (obj.isInt()) {
- *pos = (Guint)obj.getInt();
- more = gTrue;
- } else {
- more = gFalse;
- }
- obj.free();
- if (trailerDict.isNone()) {
- trailerDict.initDict(dict);
- }
-
- return more;
-
- err1:
- obj.free();
- err0:
- ok = gFalse;
- return gFalse;
-}
-
-GBool XRef::readXRefStreamSection(Stream *xrefStr, int *w, int first, int n) {
- Guint offset;
- int type, gen, c, newSize, i, j;
-
- if (first + n < 0) {
- return gFalse;
- }
- if (first + n > size) {
- for (newSize = size ? 2 * size : 1024;
- first + n > newSize && newSize > 0;
- newSize <<= 1) ;
- if (newSize < 0) {
- return gFalse;
- }
- entries = (XRefEntry *)greallocn(entries, newSize, sizeof(XRefEntry));
- for (i = size; i < newSize; ++i) {
- entries[i].offset = 0xffffffff;
- entries[i].type = xrefEntryFree;
- }
- size = newSize;
- }
- for (i = first; i < first + n; ++i) {
- if (w[0] == 0) {
- type = 1;
- } else {
- for (type = 0, j = 0; j < w[0]; ++j) {
- if ((c = xrefStr->getChar()) == EOF) {
- return gFalse;
- }
- type = (type << 8) + c;
- }
- }
- for (offset = 0, j = 0; j < w[1]; ++j) {
- if ((c = xrefStr->getChar()) == EOF) {
- return gFalse;
- }
- offset = (offset << 8) + c;
- }
- for (gen = 0, j = 0; j < w[2]; ++j) {
- if ((c = xrefStr->getChar()) == EOF) {
- return gFalse;
- }
- gen = (gen << 8) + c;
- }
- if (entries[i].offset == 0xffffffff) {
- switch (type) {
- case 0:
- entries[i].offset = offset;
- entries[i].gen = gen;
- entries[i].type = xrefEntryFree;
- break;
- case 1:
- entries[i].offset = offset;
- entries[i].gen = gen;
- entries[i].type = xrefEntryUncompressed;
- break;
- case 2:
- entries[i].offset = offset;
- entries[i].gen = gen;
- entries[i].type = xrefEntryCompressed;
- break;
- default:
- return gFalse;
- }
- }
- }
-
- return gTrue;
-}
-
-// Attempt to construct an xref table for a damaged file.
-GBool XRef::constructXRef() {
- Parser *parser;
- Object newTrailerDict, obj;
- char buf[256];
- Guint pos;
- int num, gen;
- int newSize;
- int streamEndsSize;
- char *p;
- int i;
- GBool gotRoot;
-
- gfree(entries);
- size = 0;
- entries = NULL;
-
- error(0, "PDF file is damaged - attempting to reconstruct xref table...");
- gotRoot = gFalse;
- streamEndsLen = streamEndsSize = 0;
-
- str->reset();
- while (1) {
- pos = str->getPos();
- if (!str->getLine(buf, 256)) {
- break;
- }
- p = buf;
-
- // got trailer dictionary
- if (!strncmp(p, "trailer", 7)) {
- obj.initNull();
- parser = new Parser(NULL,
- new Lexer(NULL,
- str->makeSubStream(pos + 7, gFalse, 0, &obj)));
- parser->getObj(&newTrailerDict);
- if (newTrailerDict.isDict()) {
- newTrailerDict.dictLookupNF("Root", &obj);
- if (obj.isRef()) {
- rootNum = obj.getRefNum();
- rootGen = obj.getRefGen();
- if (!trailerDict.isNone()) {
- trailerDict.free();
- }
- newTrailerDict.copy(&trailerDict);
- gotRoot = gTrue;
- }
- obj.free();
- }
- newTrailerDict.free();
- delete parser;
-
- // look for object
- } else if (isdigit(*p)) {
- num = atoi(p);
- if (num > 0) {
- do {
- ++p;
- } while (*p && isdigit(*p));
- if (isspace(*p)) {
- do {
- ++p;
- } while (*p && isspace(*p));
- if (isdigit(*p)) {
- gen = atoi(p);
- do {
- ++p;
- } while (*p && isdigit(*p));
- if (isspace(*p)) {
- do {
- ++p;
- } while (*p && isspace(*p));
- if (!strncmp(p, "obj", 3)) {
- if (num >= size) {
- newSize = (num + 1 + 255) & ~255;
- if (newSize < 0) {
- error(-1, "Bad object number");
- return gFalse;
- }
- entries = (XRefEntry *)
- greallocn(entries, newSize, sizeof(XRefEntry));
- for (i = size; i < newSize; ++i) {
- entries[i].offset = 0xffffffff;
- entries[i].type = xrefEntryFree;
- }
- size = newSize;
- }
- if (entries[num].type == xrefEntryFree ||
- gen >= entries[num].gen) {
- entries[num].offset = pos - start;
- entries[num].gen = gen;
- entries[num].type = xrefEntryUncompressed;
- }
- }
- }
- }
- }
- }
-
- } else if (!strncmp(p, "endstream", 9)) {
- if (streamEndsLen == streamEndsSize) {
- streamEndsSize += 64;
- streamEnds = (Guint *)greallocn(streamEnds,
- streamEndsSize, sizeof(int));
- }
- streamEnds[streamEndsLen++] = pos;
- }
- }
-
- if (gotRoot)
- return gTrue;
-
- error(-1, "Couldn't find trailer dictionary");
- return gFalse;
-}
-
-void XRef::setEncryption(int permFlagsA, GBool ownerPasswordOkA,
- Guchar *fileKeyA, int keyLengthA, int encVersionA) {
- int i;
-
- encrypted = gTrue;
- permFlags = permFlagsA;
- ownerPasswordOk = ownerPasswordOkA;
- if (keyLengthA <= 16) {
- keyLength = keyLengthA;
- } else {
- keyLength = 16;
- }
- for (i = 0; i < keyLength; ++i) {
- fileKey[i] = fileKeyA[i];
- }
- encVersion = encVersionA;
-}
-
-GBool XRef::okToPrint(GBool ignoreOwnerPW) {
- return (!ignoreOwnerPW && ownerPasswordOk) || (permFlags & permPrint);
-}
-
-GBool XRef::okToChange(GBool ignoreOwnerPW) {
- return (!ignoreOwnerPW && ownerPasswordOk) || (permFlags & permChange);
-}
-
-GBool XRef::okToCopy(GBool ignoreOwnerPW) {
- return (!ignoreOwnerPW && ownerPasswordOk) || (permFlags & permCopy);
-}
-
-GBool XRef::okToAddNotes(GBool ignoreOwnerPW) {
- return (!ignoreOwnerPW && ownerPasswordOk) || (permFlags & permNotes);
-}
-
-Object *XRef::fetch(int num, int gen, Object *obj) {
- XRefEntry *e;
- Parser *parser;
- Object obj1, obj2, obj3;
-
- // check for bogus ref - this can happen in corrupted PDF files
- if (num < 0 || num >= size) {
- goto err;
- }
-
- e = &entries[num];
- switch (e->type) {
-
- case xrefEntryUncompressed:
- if (e->gen != gen) {
- goto err;
- }
- obj1.initNull();
- parser = new Parser(this,
- new Lexer(this,
- str->makeSubStream(start + e->offset, gFalse, 0, &obj1)));
- parser->getObj(&obj1);
- parser->getObj(&obj2);
- parser->getObj(&obj3);
- if (!obj1.isInt() || obj1.getInt() != num ||
- !obj2.isInt() || obj2.getInt() != gen ||
- !obj3.isCmd("obj")) {
- obj1.free();
- obj2.free();
- obj3.free();
- delete parser;
- goto err;
- }
- parser->getObj(obj, encrypted ? fileKey : (Guchar *)NULL, keyLength,
- num, gen);
- obj1.free();
- obj2.free();
- obj3.free();
- delete parser;
- break;
-
- case xrefEntryCompressed:
- if (gen != 0) {
- goto err;
- }
- if (!objStr || objStr->getObjStrNum() != (int)e->offset) {
- if (objStr) {
- delete objStr;
- }
- objStr = new ObjectStream(this, e->offset);
- }
- objStr->getObject(e->gen, num, obj);
- break;
-
- default:
- goto err;
- }
-
- return obj;
-
- err:
- return obj->initNull();
-}
-
-Object *XRef::getDocInfo(Object *obj) {
- return trailerDict.dictLookup("Info", obj);
-}
-
-// Added for the pdftex project.
-Object *XRef::getDocInfoNF(Object *obj) {
- return trailerDict.dictLookupNF("Info", obj);
-}
-
-GBool XRef::getStreamEnd(Guint streamStart, Guint *streamEnd) {
- int a, b, m;
-
- if (streamEndsLen == 0 ||
- streamStart > streamEnds[streamEndsLen - 1]) {
- return gFalse;
- }
-
- a = -1;
- b = streamEndsLen - 1;
- // invariant: streamEnds[a] < streamStart <= streamEnds[b]
- while (b - a > 1) {
- m = (a + b) / 2;
- if (streamStart <= streamEnds[m]) {
- b = m;
- } else {
- a = m;
- }
- }
- *streamEnd = streamEnds[b];
- return gTrue;
-}
-
-Guint XRef::strToUnsigned(char *s) {
- Guint x;
- char *p;
- int i;
-
- x = 0;
- for (p = s, i = 0; *p && isdigit(*p) && i < 10; ++p, ++i) {
- x = 10 * x + (*p - '0');
- }
- return x;
-}
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