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/** \file QTarDecode.cpp
\brief To read a tar data block
\author alpha_one_x86
\licence GPL3, see the file COPYING */
#include "QTarDecode.h"
#include <inttypes.h>
#include <regex>
#include <cstring>
#include <iostream>
static const std::regex isaunsignednumber("^[0-9]+$",std::regex::optimize);
static const std::regex isaunoctalnumber("^[0-7]+$",std::regex::optimize);
//static const char* const lut = "0123456789ABCDEF";
QTarDecode::QTarDecode()
{
error="Unknown error";
}
uint64_t QTarDecode::octaltouint64(const std::string &string,bool *ok)
{
if(std::regex_match(string,isaunsignednumber))
{
if(ok!=NULL)
*ok=true;
return std::stoi(string,0,8);
}
else
{
if(ok!=NULL)
*ok=false;
return 0;
}
}
uint64_t QTarDecode::stringtouint64(const std::string &string,bool *ok)
{
if(std::regex_match(string,isaunsignednumber))
{
if(ok!=NULL)
*ok=true;
return std::stoull(string);
}
else
{
if(ok!=NULL)
*ok=false;
return 0;
}
}
std::string QTarDecode::errorString()
{
return error;
}
void QTarDecode::setErrorString(const std::string &error)
{
this->error=error;
fileList.clear();
dataList.clear();
}
bool QTarDecode::stringStartWith(std::string const &fullString, std::string const &starting)
{
if (fullString.length() >= starting.length()) {
return (fullString.substr(0,starting.length())==starting);
} else {
return false;
}
}
bool QTarDecode::decodeData(const std::vector<char> &data)
{
setErrorString("Unknown error");
if(data.size()<1024)
return false;
unsigned int offset=0;
while(offset<data.size())
{
//load the file name from ascii, from 0+offset with size of 100
std::string fileName(data.data()+offset,100);
while(!fileName.empty() && fileName.at(fileName.size()-1)==0x00)
fileName.resize(fileName.size()-1);
//load the file type
std::string fileType(data.data()+156+offset,1);
while(!fileName.empty() && fileType.at(fileType.size()-1)==0x00)
fileType.resize(fileType.size()-1);
//load the ustar string
std::string ustar(data.data()+257+offset,5);
while(!fileName.empty() && ustar.at(ustar.size()-1)==0x00)
ustar.resize(ustar.size()-1);
//load the ustar version
std::string ustarVersion(data.data()+263+offset,2);
while(!fileName.empty() && ustarVersion.at(ustarVersion.size()-1)==0x00)
ustarVersion.resize(ustarVersion.size()-1);
bool ok=false;
//load the file size from ascii, from 124+offset with size of 12
uint64_t finalSize=0;
std::string sizeString(data.data()+124+offset,12);
if(sizeString.at(sizeString.size()-1)==0x00)
{
//the size is in octal base
sizeString.resize(sizeString.size()-1);
finalSize=octaltouint64(sizeString,&ok);
}
else
finalSize=stringtouint64(sizeString,&ok);
//if the size conversion to qulonglong have failed, then qui with error
if(ok==false)
{
//it's the end of the archive, no more verification
break;
}
//if check if the ustar not found
if(ustar!="ustar")
{
setErrorString("\"ustar\" string not found at "+std::to_string(257+offset)+", content: \""+ustar+"\"");
return false;
}
if(ustarVersion!="00")
{
setErrorString("ustar version string is wrong, content:\""+ustarVersion+"\"");
return false;
}
//check if the file have the good size for load the data
if((offset+512+finalSize)>data.size())
{
setErrorString("The tar file seem be too short");
return false;
}
if(fileType=="0") //this code manage only the file, then only the file is returned
{
std::vector<char> newdata;
newdata.resize(finalSize);
memcpy(newdata.data(),data.data()+512+offset,finalSize);
fileList.push_back(fileName);
dataList.push_back(newdata);
}
//calculate the offset for the next header
bool retenu=((finalSize%512)!=0);
//go to the next header
offset+=512+(finalSize/512+retenu)*512;
}
if(fileList.size()>0)
{
std::string baseDirToTest=fileList.at(0);
std::size_t found = baseDirToTest.find_last_of("/");
if(found!=std::string::npos && found>=baseDirToTest.size())
baseDirToTest.resize(baseDirToTest.size()-(baseDirToTest.size()-found));
bool isFoundForAllEntries=true;
for (unsigned int i = 0; i < fileList.size(); ++i)
if(!stringStartWith(fileList.at(i),baseDirToTest))
isFoundForAllEntries=false;
if(isFoundForAllEntries)
for (unsigned int i = 0; i < fileList.size(); ++i)
fileList[i].erase(0,baseDirToTest.size());
}
return true;
}
std::vector<std::string> QTarDecode::getFileList()
{
return fileList;
}
std::vector<std::vector<char> > QTarDecode::getDataList()
{
return dataList;
}
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