Initial commit

This commit is contained in:
Grégory Soutadé 2021-08-21 18:22:58 +02:00
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.gitignore vendored Normal file
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*~
libupdfparser.a
libupdfparser.so

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LICENSE Normal file
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GNU LESSER GENERAL PUBLIC LICENSE
Version 3, 29 June 2007
Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
This version of the GNU Lesser General Public License incorporates
the terms and conditions of version 3 of the GNU General Public
License, supplemented by the additional permissions listed below.
0. Additional Definitions.
As used herein, "this License" refers to version 3 of the GNU Lesser
General Public License, and the "GNU GPL" refers to version 3 of the GNU
General Public License.
"The Library" refers to a covered work governed by this License,
other than an Application or a Combined Work as defined below.
An "Application" is any work that makes use of an interface provided
by the Library, but which is not otherwise based on the Library.
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of using an interface provided by the Library.
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Application with the Library. The particular version of the Library
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and utility programs needed for reproducing the Combined Work from the
Application, but excluding the System Libraries of the Combined Work.
1. Exception to Section 3 of the GNU GPL.
You may convey a covered work under sections 3 and 4 of this License
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2. Conveying Modified Versions.
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facility refers to a function or data to be supplied by an Application
that uses the facility (other than as an argument passed when the
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You may place library facilities that are a work based on the
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6. Revised Versions of the GNU Lesser General Public License.
The Free Software Foundation may publish revised and/or new versions
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AR ?= $(CROSS)ar
CXX ?= $(CROSS)g++
CXXFLAGS=-Wall -fPIC -I./include
LDFLAGS=
BUILD_STATIC ?= 0
BUILD_SHARED ?= 1
TARGETS =
ifneq (BUILD_STATIC, 0)
TARGETS += libupdfparser.a
endif
ifneq (BUILD_SHARED, 0)
TARGETS += libupdfparser.so
endif
ifneq ($(DEBUG),)
CXXFLAGS += -ggdb -O0
else
CXXFLAGS += -O2
endif
SRCDIR := src
INCDIR := inc
BUILDDIR := obj
TARGETDIR := bin
SRCEXT := cpp
OBJEXT := o
SOURCES = src/uPDFParser.cpp src/uPDFTypes.cpp
OBJECTS := $(patsubst $(SRCDIR)/%,$(BUILDDIR)/%,$(SOURCES:.$(SRCEXT)=.$(OBJEXT)))
all: obj $(TARGETS)
obj:
mkdir obj
$(BUILDDIR)/%.$(OBJEXT): $(SRCDIR)/%.$(SRCEXT)
$(CXX) $(CXXFLAGS) -c $^ -o $@
libupdfparser.a: $(OBJECTS)
$(AR) crs $@ obj/*.o
libupdfparser.so: $(OBJECTS)
$(CXX) obj/*.o $(LDFLAGS) -o $@ -shared
test: test.c libupdfparser.a
g++ -ggdb -O0 $^ -o $@ -Iinclude libupdfparser.a
clean:
rm -rf libupdfparser.so libupdfparser.a obj

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Introduction
------------
A very simple PDF parser that will load PDF objects without interpretation (zlib, streams, string encoding...).
It currently only allows to update PDF file with new objects.
Compilation
-----------
Use _make_ command
make [CROSS=XXX] [DEBUG=1] [BUILD_STATIC=(0|1)] [BUILD_SHARED=(0|1)]
CROSS can define a cross compiler prefix (ie arm-linux-gnueabihf-)
DEBUG can be set to compile in DEBUG mode
BUILD_STATIC build libupdfparser.a if 1, nothing if 0 (default value), can be combined with BUILD_SHARED
BUILD_SHARED build libupdfparser.so if 1 (default value), nothing if 0, can be combined with BUILD_STATIC
Copyright
---------
Grégory Soutadé
License
-------
LGPL v3 or later

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/*
Copyright 2021 Grégory Soutadé
This file is part of uPDFParser.
uPDFParser is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
uPDFParser is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with uPDFParser. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _UPDFOBJECT_HPP_
#define _UPDFOBJECT_HPP_
#include "uPDFTypes.h"
namespace uPDFParser
{
/**
* @brief PDF Object
*/
class Object
{
public:
Object():
_objectId(0), _generationNumber(0),
offset(0), _isNew(false), indirectOffset(0)
{}
/**
* @brief Object constructor
*
* @param objectId Object ID
* @param generationNumber Object generation number
* @param offset Offset of object in current PDF file
* @param isNew false if object has been read from file,
* true if it has been created or updated
* @param indirectOffset Object is indirect
*/
Object(int objectId, int generationNumber, uint64_t offset, bool isNew=false,
off_t indirectOffset=0):
_objectId(objectId), _generationNumber(generationNumber),
offset(offset), _isNew(isNew), indirectOffset(indirectOffset)
{}
~Object()
{
std::vector<DataType*>::iterator it;
for(it=_data.begin(); it!=_data.end(); it++)
delete *it;
}
Object(const Object& other)
{
_objectId = other._objectId;
_generationNumber = other._generationNumber;
offset = other.offset;
indirectOffset = other.indirectOffset;
_isNew = true;
std::vector<DataType*>::const_iterator it;
for(it=other._data.begin(); it!=other._data.end(); it++)
_data.push_back((*it)->clone());
const std::map<std::string, DataType*> _dict = ((Dictionary)other._dictionary).value();
std::map<std::string, DataType*>& _myDict = _dictionary.value();
std::map<std::string, DataType*>::const_iterator it2;
for(it2=_dict.begin(); it2!=_dict.end(); it2++)
_myDict[it2->first] = it2->second->clone();
}
/**
* @brief Clone current object (call copy constructor)
*/
Object* clone() { return new Object(*this); }
/**
* @brief Return internal dictionary
*/
Dictionary& dictionary() {return _dictionary;}
/**
* @brief Return vector of data contained into object
*/
std::vector<DataType*>& data() {return _data;}
/**
* @brief Object string representation
*/
std::string str();
/**
* @brief Set object as indirect if offset != 0 or not indirect if offset == 0
*/
void setIndirectOffset(off_t offset) {indirectOffset = offset;}
/**
* @brief is object indirect (indirectOffset != 0)
*/
bool isIndirect() {return indirectOffset != 0;}
/**
* @brief Get dictionary value
*/
DataType*& operator[](const std::string& key) { return _dictionary.value()[key]; }
/**
* @brief Check for key in object's dictionary
*/
bool hasKey(const std::string& key) { return _dictionary.value().count(key)?true:false; }
/**
* @brief is object new (or not updated) ?
*/
bool isNew() { return _isNew; }
/**
* @brief Mark object as updated
*/
void update(void) { _isNew = true; }
/**
* @brief Return object's id
*/
int objectId() { return _objectId; }
/**
* @brief Return object's generation number
*/
int generationNumber() { return _generationNumber; }
private:
int _objectId;
int _generationNumber;
off_t offset;
bool _isNew;
off_t indirectOffset;
Dictionary _dictionary;
std::vector<DataType*> _data;
};
}
#endif

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/*
Copyright 2021 Grégory Soutadé
This file is part of uPDFParser.
uPDFParser is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
uPDFParser is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with uPDFParser. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _UPDFPARSER_HPP_
#define _UPDFPARSER_HPP_
#include <exception>
#include <map>
#include <vector>
#include <string>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <string.h>
#include <unistd.h>
#include "uPDFTypes.h"
#include "uPDFObject.h"
namespace uPDFParser
{
/**
* @brief PDF Parser
*/
class Parser
{
public:
Parser():
fd(0)
{}
~Parser()
{
if (fd) close(fd);
std::vector<Object*>::iterator it;
for(it=_objects.begin(); it!=_objects.end(); it++)
delete *it;
}
/**
* @brief Parse a file
*/
void parse(const std::string& filename);
/**
* @brief Write a PDF file with internal objects
*
* @param filename File path
* @param update Only append new objects if true
* Write a new PDF file if false (not supported for now)
*/
void write(const std::string& filename, bool update=false);
/**
* @brief Get internals (or parsed) objects
*/
std::vector<Object*>& objects() { return _objects; }
/**
* @brief Add an object
*/
void addObject(Object* object) { _objects.push_back(object); }
private:
void parseObject(std::string& token);
void parseXref();
void parseTrailer();
std::string nextToken(bool exceptionOnEOF=true);
DataType* parseType(std::string& token, Object* object, std::map<std::string, DataType*>& dict);
void parseDictionary(Object* object, std::map<std::string, DataType*>& dict);
DataType* parseSignedNumber(std::string& token);
DataType* parseNumber(std::string& token);
DataType* parseNumberOrReference(std::string& token);
Array* parseArray(Object* object);
String* parseString();
HexaString* parseHexaString();
Stream* parseStream();
Name* parseName(std::string& token);
void writeUpdate(const std::string& filename);
std::vector<Object*> _objects;
Object trailer;
off_t xrefOffset;
int fd;
off_t curOffset;
};
}
#endif

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#ifndef _UPDFPARSER_COMMON_HPP_
#define _UPDFPARSER_COMMON_HPP_
#include <sstream>
#include <iomanip>
#include <string.h>
namespace uPDFParser
{
enum PARSING_ERROR {
UNABLE_TO_OPEN_FILE = 1,
TRUNCATED_FILE,
INVALID_HEADER,
INVALID_LINE,
INVALID_FOOTER,
INVALID_DICTIONARY,
INVALID_NAME,
INVALID_BOOLEAN,
INVALID_NUMBER,
INVALID_STREAM,
INVALID_TOKEN,
INVALID_OBJECT,
INVALID_TRAILER,
INVALID_HEXASTRING,
NOT_IMPLEMENTED
};
/**
* @brief Exception class
*/
class Exception : public std::exception
{
public:
Exception(int code, const char* message, const char* file, int line):
code(code), line(line), file(file)
{
std::stringstream msg;
msg << "Exception code : 0x" << std::setbase(16) << code << std::endl;
msg << "Message : " << message << std::endl;
msg << "File : " << file << ":" << std::setbase(10) << line << std::endl;
fullmessage = strdup(msg.str().c_str());
}
Exception(const Exception& other)
{
this->code = other.code;
this->line = line;
this->file = file;
this->fullmessage = strdup(other.fullmessage);
}
~Exception()
{
free(fullmessage);
}
const char * what () const throw () { return fullmessage; }
int getErrorCode() {return code;}
private:
int code, line;
const char* message, *file;
char* fullmessage;
};
#define EXCEPTION(code, message) \
{std::stringstream __msg;__msg << message; throw uPDFParser::Exception(code, __msg.str().c_str(), __FILE__, __LINE__);}
}
#endif

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/*
Copyright 2021 Grégory Soutadé
This file is part of uPDFParser.
uPDFParser is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
uPDFParser is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with uPDFParser. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _UPDFTYPES_HPP_
#define _UPDFTYPES_HPP_
#include <map>
#include <vector>
#include <string>
#include <iostream>
#include <sstream>
namespace uPDFParser
{
/**
* @brief Base class for PDF object type
* From https://resources.infosecinstitute.com/topic/pdf-file-format-basic-structure/
*/
class DataType
{
public:
enum TYPE {BOOLEAN, INTEGER, REAL, NAME, STRING, HEXASTRING, REFERENCE, ARRAY, DICTIONARY, STREAM};
DataType(TYPE _type):
_type(_type)
{}
virtual ~DataType() {}
/**
* @brief Get current data type
*/
TYPE type() { return _type; }
/**
* @brief String representation for serialization
*/
virtual std::string str() = 0;
/**
* @brief Clone current object
*/
virtual DataType* clone() = 0;
protected:
TYPE _type;
};
class Boolean : public DataType
{
public:
Boolean(bool value):
DataType(DataType::TYPE::BOOLEAN), _value(value)
{}
virtual DataType* clone() {return new Boolean(_value);}
bool value() {return _value;}
virtual std::string str() { return (_value)?" true":" false";}
private:
bool _value;
};
class Integer : public DataType
{
public:
Integer(int value, bool _signed=false):
DataType(DataType::TYPE::INTEGER), _value(value), _signed(_signed)
{}
virtual DataType* clone() {return new Integer(_value, _signed);}
int value() {return _value;}
virtual std::string str();
private:
int _value;
bool _signed;
};
class Real : public DataType
{
public:
Real(float value, bool _signed=false):
DataType(DataType::TYPE::REAL), _value(value), _signed(_signed)
{}
virtual DataType* clone() {return new Real(_value, _signed);}
float value() {return _value;}
virtual std::string str();
private:
float _value;
bool _signed;
};
class Name : public DataType
{
public:
Name(const std::string&);
virtual DataType* clone() {return new Name(_value);}
std::string value() {
const char* name = _value.c_str();
return std::string(&name[1]);
}
virtual std::string str() { return _value;}
private:
std::string _value;
};
class String : public DataType
{
public:
String(const std::string&);
virtual DataType* clone() {return new String(_value);}
std::string value() {return _value;}
// Escape '(' and ')' characters
virtual std::string str() {
char prev = '\0';
std::string res("(");
for(unsigned int i=0; i<_value.size(); i++)
{
if ((_value[i] == '(' || _value[i] == ')') &&
prev != '\\')
res += '\\';
res += _value[i];
prev = _value[i];
}
res += ")";
return res;
}
private:
std::string _value;
};
class HexaString : public DataType
{
public:
HexaString(const std::string&);
virtual DataType* clone() {return new HexaString(_value);}
std::string value() {return _value;}
virtual std::string str() { return std::string("<") + _value + std::string(">");}
private:
std::string _value;
};
class Reference : public DataType
{
public:
Reference(int objectId, int generationNumber):
DataType(DataType::TYPE::REFERENCE), objectId(objectId), generationNumber(generationNumber)
{}
virtual DataType* clone() {return new Reference(objectId, generationNumber);}
int value() {return objectId;}
virtual std::string str() {
std::stringstream res;
res << " " << objectId << " " << generationNumber << " R";
return res.str();
}
private:
int objectId, generationNumber;
};
class Array : public DataType
{
public:
Array():
DataType(DataType::TYPE::ARRAY)
{}
void addData(DataType* data) {_value.push_back(data);}
virtual DataType* clone() {
Array* res = new Array();
std::vector<DataType*>::iterator it;
for(it=_value.begin(); it!=_value.end(); it++)
res->addData((*it)->clone());
return res;
}
std::vector<DataType*>& value() {return _value;}
virtual std::string str();
private:
std::vector<DataType*> _value;
};
class Dictionary : public DataType
{
public:
Dictionary():
DataType(DataType::TYPE::DICTIONARY)
{}
void addData(const std::string&, DataType*);
virtual DataType* clone() {
Dictionary* res = new Dictionary();
std::map<std::string, DataType*>::iterator it;
for(it=_value.begin(); it!=_value.end(); it++)
{
res->addData(it->first, it->second->clone());
}
return res;
}
std::map<std::string, DataType*>& value() {return _value;}
virtual std::string str();
private:
std::map<std::string, DataType*> _value;
};
class Stream : public DataType
{
public:
Stream(int startOffset, int endOffset):
DataType(DataType::TYPE::STREAM), startOffset(startOffset),
endOffset(endOffset)
{}
virtual DataType* clone() {return new Stream(startOffset, endOffset);}
virtual std::string str() { return "stream\nendstream\n";}
private:
int startOffset, endOffset;
};
}
#endif

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/*
Copyright 2021 Grégory Soutadé
This file is part of uPDFParser.
uPDFParser is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
uPDFParser is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with uPDFParser. If not, see <http://www.gnu.org/licenses/>.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include "uPDFParser.h"
#include "uPDFParser_common.h"
namespace uPDFParser
{
std::string Object::str()
{
std::stringstream res;
res << _objectId << " " << _generationNumber << " obj\n";
res << _dictionary.str();
std::vector<DataType*>::iterator it;
for(it=_data.begin(); it!=_data.end(); it++)
res << (*it)->str();
res << "endobj\n";
return res.str();
}
/**
* @brief Read data until '\n' or '\r' is found or buffer is full
*/
static inline int readline(int fd, char* buffer, int size, bool exceptionOnEOF=true)
{
int res = 0;
char c;
buffer[0] = 0;
for (;size;size--,res++)
{
if (read(fd, &c, 1) != 1)
{
if (exceptionOnEOF)
EXCEPTION(TRUNCATED_FILE, "Unexpected end of file");
return -1;
}
if (c == '\n' || c == '\r')
break;
buffer[res] = c;
}
if (size)
buffer[res] = 0;
return res;
}
/**
* @brief Read data until EOF, '\n' or '\r' is found
*/
static inline void finishLine(int fd)
{
char c;
while (1)
{
if (read(fd, &c, 1) != 1)
break;
if (c == '\n')
break;
}
}
/**
* @brief Find next token to analyze
*/
std::string Parser::nextToken(bool exceptionOnEOF)
{
char c;
std::string res("");
int i;
static const char delims[] = " \t<>[]()+-/";
static const char start_delims[] = "<>[]()";
bool found = false;
while (!found)
{
if (read(fd, &c, 1) != 1)
{
if (exceptionOnEOF)
EXCEPTION(TRUNCATED_FILE, "Unexpected end of file");
break;
}
// Comment, skip line
if (c == '%')
{
finishLine(fd);
break;
}
// White character while empty result, continue
if ((c == ' ' || c == '\t' || c == '\n' || c == '\r' || c == '\0') && !res.size())
continue;
// Quit on line return without lseek(fd, -1, SEEK_CUR)
if (c == '\n' || c == '\r')
{
if (res.size())
break;
else
continue;
}
if (res.size())
{
// Push character until delimiter is found
for (i=0; i<(int)sizeof(delims); i++)
{
if (c == delims[i])
{
lseek(fd, -1, SEEK_CUR);
found = true;
break;
}
}
if (!found)
res += c;
}
else
{
curOffset = lseek(fd, 0, SEEK_CUR)-1;
// First character, is it a delimiter ?
for (i=0; i<(int)sizeof(start_delims); i++)
{
if (c == start_delims[i])
{
found = true;
break;
}
}
res += c;
}
}
// Double '>' and '<' to compute dictionary
if (res == ">" || res == "<")
{
if (read(fd, &c, 1) == 1)
{
if (c == res[0])
res += c;
else
lseek(fd, -1, SEEK_CUR);
}
}
return res;
}
void Parser::parseTrailer()
{
std::string token;
char buffer[10];
// std::cout << "Parse trailer" << std::endl;
token = nextToken();
if (token != "<<")
EXCEPTION(INVALID_TRAILER, "Invalid trailer at offset " << curOffset);
parseDictionary(&trailer, trailer.dictionary().value());
token = nextToken();
if (token != "startxref")
EXCEPTION(INVALID_TRAILER, "Invalid trailer at offset " << curOffset);
token = nextToken();
readline(fd, buffer, sizeof(buffer), false);
if (strncmp(buffer, "%%EOF", 5))
EXCEPTION(INVALID_TRAILER, "Invalid trailer at offset " << curOffset);
}
void Parser::parseXref()
{
std::string token;
// std::cout << "Parse xref" << std::endl;
xrefOffset = curOffset;
while (1)
{
token = nextToken();
if (token == "trailer")
{
parseTrailer();
break;
}
}
}
static DataType* tokenToNumber(std::string& token, char sign='\0')
{
int i;
float fvalue;
int ivalue;
for(i=0; i<(int)token.size(); i++)
{
if (token[i] == '.')
{
if (i==0) token = std::string("0") + token;
fvalue = std::stof(token);
if (sign == '-')
fvalue = -fvalue;
return new Real(fvalue, (sign!='\0'));
}
}
ivalue = std::stoi(token);
if (sign == '-')
ivalue = -ivalue;
return new Integer(ivalue, (sign!='\0'));
}
DataType* Parser::parseSignedNumber(std::string& token)
{
char sign = token[0];
token = std::string(&((token.c_str())[1]));
return tokenToNumber(token, sign);
}
DataType* Parser::parseNumber(std::string& token)
{
return tokenToNumber(token);
}
DataType* Parser::parseNumberOrReference(std::string& token)
{
DataType* res = tokenToNumber(token);
if (res->type() == DataType::TYPE::REAL)
return res;
off_t offset = lseek(fd, 0, SEEK_CUR);
std::string token2 = nextToken();
std::string token3 = nextToken();
DataType* generationNumber = 0;
try
{
generationNumber = tokenToNumber(token2);
}
catch (std::invalid_argument& e)
{
lseek(fd, offset, SEEK_SET);
return res;
}
if ((generationNumber->type() != DataType::TYPE::INTEGER) ||
token3.size() != 1 || token3[0] != 'R')
{
delete generationNumber;
lseek(fd, offset, SEEK_SET);
return res;
}
DataType* res2 = new Reference(((Integer*)res)->value(),
((Integer*)generationNumber)->value());
delete res;
return res2;
}
DataType* Parser::parseType(std::string& token, Object* object, std::map<std::string, DataType*>& dict)
{
DataType* value = 0;
Dictionary* _value = 0;
if (token == "<<")
{
_value = new Dictionary();
value = _value;
parseDictionary(object, _value->value());
}
else if (token == "[")
value = parseArray(object);
else if (token == "(")
value = parseString();
else if (token == "<")
value = parseHexaString();
else if (token == "stream")
value = parseStream();
else if (token[0] >= '1' && token[0] <= '9')
value = parseNumberOrReference(token);
else if (token[0] == '/')
value = parseName(token);
else if (token[0] == '+' || token[0] == '-')
value = parseSignedNumber(token);
else if (token[0] == '0' || token[0] == '.')
value = parseNumber(token);
else if (token == "true")
return new Boolean(true);
else if (token == "false")
return new Boolean(false);
else
EXCEPTION(INVALID_TOKEN, "Invalid token " << token << " at offset " << curOffset);
return value;
}
Array* Parser::parseArray(Object* object)
{
std::string token;
DataType* value;
Array* res = new Array();
while (1)
{
token = nextToken();
if (token == "]")
break;
value = parseType(token, object, object->dictionary().value());
//std::cout << "Add " << value->str() << std::endl;
res->addData(value);
}
return res;
}
String* Parser::parseString()
{
std::string res("");
char c;
bool escaped = false;
while (1)
{
if (read(fd, &c, 1) != 1)
break;
if (c == ')' && !escaped)
break;
escaped = (c == '\\');
res += c;
}
return new String(res);
}
HexaString* Parser::parseHexaString()
{
std::string res("");
char c;
while (1)
{
if (read(fd, &c, 1) != 1)
break;
if (c == '>')
break;
res += c;
}
if ((res.size() % 2))
EXCEPTION(INVALID_HEXASTRING, "Invalid hexa String at offset " << curOffset);
return new HexaString(res);
}
Stream* Parser::parseStream()
{
char buffer[1024];
off_t endOffset;
while (1)
{
endOffset = lseek(fd, 0, SEEK_CUR);
readline(fd, buffer, sizeof(buffer));
if (!strncmp(buffer, "endstream", 9))
break;
}
return new Stream(curOffset, endOffset);
}
Name* Parser::parseName(std::string& name)
{
if (!name.size() || name[0] != '/')
EXCEPTION(INVALID_NAME, "Invalid Name at offset " << curOffset);
//std::cout << "Name " << name << std::endl;
return new Name(name);
}
void Parser::parseDictionary(Object* object, std::map<std::string, DataType*>& dict)
{
std::string token;
Name* key;
DataType* value;
while (1)
{
token = nextToken();
if (token == ">>")
break;
key = parseName(token);
token = nextToken();
if (token == ">>")
{
dict[key->value()] = 0;
break;
}
value = parseType(token, object, dict);
dict[key->value()] = value;
}
}
void Parser::parseObject(std::string& token)
{
off_t offset;
int objectId, generationNumber;
Object* object;
offset = curOffset;
try
{
objectId = std::stoi(token);
token = nextToken();
generationNumber = std::stoi(token);
}
catch(std::invalid_argument& e)
{
EXCEPTION(INVALID_OBJECT, "Invalid object at offset " << curOffset);
}
token = nextToken();
if (token != "obj")
EXCEPTION(INVALID_OBJECT, "Invalid object at offset " << curOffset);
std::cout << "New obj " << objectId << " " << generationNumber << std::endl;
object = new Object(objectId, generationNumber, offset);
_objects.push_back(object);
while (1)
{
token = nextToken();
if (token == "endobj")
break;
if (token == "<<")
parseDictionary(object, object->dictionary().value());
else if (token[0] >= '1' && token[0] <= '9')
{
DataType* _offset = tokenToNumber(token);
if (_offset->type() != DataType::TYPE::INTEGER)
EXCEPTION(INVALID_OBJECT, "Invalid object at offset " << curOffset);
object->setIndirectOffset(((Integer*)_offset)->value());
}
else
parseType(token, object, object->dictionary().value());
}
}
void Parser::parse(const std::string& filename)
{
char buf[16];
std::string token;
if (fd)
close(fd);
fd = open(filename.c_str(), O_RDONLY);
if (fd <= 0)
EXCEPTION(UNABLE_TO_OPEN_FILE, "Unable to open " << filename << " (%m)");
// Check %PDF at startup
readline(fd, buf, 4);
if (strncmp(buf, "%PDF", 4))
EXCEPTION(INVALID_HEADER, "Invalid PDF header");
finishLine(fd);
curOffset = lseek(fd, 0, SEEK_CUR);
// // Check %%EOF at then end
// lseek(fd, -5, SEEK_END);
// readline(fd, buf, 5);
// if (strncmp(buf, "%%EOF", 5))
// EXCEPTION(INVALID_FOOTER, "Invalid PDF footer");
lseek(fd, curOffset, SEEK_SET);
while (1)
{
token = nextToken(false);
if (!token.size())
break;
if (token == "xref")
parseXref();
else if (token[0] >= '1' && token[0] <= '9')
parseObject(token);
else
EXCEPTION(INVALID_LINE, "Invalid Line at offset " << curOffset);
}
close(fd);
}
void Parser::writeUpdate(const std::string& filename)
{
int newFd = open(filename.c_str(), O_WRONLY|O_APPEND|O_CREAT, S_IRUSR|S_IWUSR);
if (newFd <= 0)
EXCEPTION(UNABLE_TO_OPEN_FILE, "Unable to open " << filename << " (%m)");
::write(newFd, "\r", 1);
std::stringstream xref;
int nbNewObjects = 0;
xref << std::setfill('0');
xref << "xref\n";
std::vector<Object*>::iterator it;
for(it=_objects.begin(); it!=_objects.end(); it++)
{
if (!(*it)->isNew())
continue;
nbNewObjects ++;
std::string objStr = (*it)->str();
curOffset = lseek(newFd, 0, SEEK_CUR);
::write(newFd, objStr.c_str(), objStr.size());
xref << std::setw(0) << (*it)->objectId() << " 1\n";
xref << std::setw(10) << curOffset << " " << std::setw(5) << (*it)->generationNumber() << " n\r\n"; // Here \r seems important
}
if (!nbNewObjects)
{
close(newFd);
return;
}
off_t newXrefOffset = lseek(newFd, 0, SEEK_CUR);
std::string xrefStr = xref.str();
::write(newFd, xrefStr.c_str(), xrefStr.size());
if (trailer.hasKey("Prev"))
delete trailer["Prev"];
trailer["Prev"] = new Integer((int)xrefOffset);
std::string trailerStr = trailer.dictionary().str();
::write(newFd, "trailer\n", 8);
::write(newFd, trailerStr.c_str(), trailerStr.size());
std::stringstream startxref;
startxref << "startxref\n" << newXrefOffset << "\n%%EOF";
std::string startxrefStr = startxref.str();
::write(newFd, startxrefStr.c_str(), startxrefStr.size());
close(newFd);
}
void Parser::write(const std::string& filename, bool update)
{
if (update)
return writeUpdate(filename);
else
EXCEPTION(NOT_IMPLEMENTED, "Full write not implemented");
}
}

105
src/uPDFTypes.cpp Normal file
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/*
Copyright 2021 Grégory Soutadé
This file is part of uPDFParser.
uPDFParser is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
uPDFParser is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with uPDFParser. If not, see <http://www.gnu.org/licenses/>.
*/
#include "uPDFTypes.h"
#include "uPDFParser_common.h"
namespace uPDFParser
{
Name::Name(const std::string& name):
DataType(DataType::TYPE::NAME)
{
_value = name;
}
String::String(const std::string& value):
DataType(DataType::TYPE::STRING)
{
_value = value;
}
HexaString::HexaString(const std::string& value):
DataType(DataType::TYPE::HEXASTRING)
{
_value = value;
}
std::string Integer::str()
{
std::string sign("");
if (_signed)
{
if (_value >= 0)
sign = "+";
else
sign = "-";
}
return " " + sign + std::to_string(_value);
}
std::string Real::str()
{
std::string sign("");
if (_signed)
{
if (_value >= 0)
sign = "+";
else
sign = "-";
}
return " " + sign + std::to_string(_value);
}
std::string Array::str()
{
std::string res("[");
std::vector<DataType*>::iterator it;
for(it = _value.begin(); it!=_value.end(); it++)
{
if (res.size() > 1)
res += " ";
res += (*it)->str();
}
return res + std::string("]");
}
void Dictionary::addData(const std::string& key, DataType* value)
{