redirect.h

string PARSE_REDIRECT(string input)
{
    vector<char> token;
    int pos=0;
    while(input[pos]!='\0')
    {
        if(input[pos]=='<' || input[pos]=='>')
        {
            token.push_back(input[pos]);
            token.push_back(' ');
            pos++;
        }
        else if(input[pos+1]=='<' || input[pos+1]=='>')
        {
            token.push_back(input[pos]);
            token.push_back(' ');
            pos++;
        }
        else
        {
            token.push_back(input[pos]);
            pos++;
        }
    }
    string s(token.begin(),token.end());
    return s;
}

void REDIRECT(string input)
{
    int pd[2];
    pipe(pd);
    if(!fork())
    {
int fd0=0;
int fd1=0;
    char  *command[1000];
    string com;
    int i=0;
    for(int i=0;i<1000;i++)
    {
        command[i]='\0';
    }
    char input_source[1000];
    char output_source[1000];
    vector<string> space_split;
    vector<string>::iterator over_space;
    com=PARSE_REDIRECT(input);
    space_split=PARSE_STRING(com,' ');
    for(over_space=space_split.begin();over_space!=space_split.end();over_space++)
    {
        if((*over_space).compare("<")==0)
        {
            strcpy(input_source,(*(over_space+1)).c_str());
        }
        else if((*over_space).compare(">")==0)
        {
            strcpy(output_source,(*(over_space+1)).c_str());
        }
    }
    for(over_space=space_split.begin();over_space!=space_split.end();over_space++)
    {
        if((*over_space).compare("<")==0 || (*over_space).compare(">")==0)
        {
            over_space=over_space+1;
        }
        else
        {
            command[i]=new char[1000];
            strcpy(command[i],(*over_space).c_str());
            i++;
        }
    }
    
   close(1);
        dup2(pd[1],1);
if(strlen(input_source)!=0)
    {
        fd0 = open(input_source,O_RDONLY);
        dup2(fd0, STDIN_FILENO);
        close(fd0);
    }
    if (strlen(output_source)!=0)
    {
        fd1 = creat(output_source, 0666) ;
        dup2(fd1, STDOUT_FILENO);
        close(fd1);
    }
        
        execvp(command[0],command);
        abort();
    }
    wait(0);
    dup2(pd[0],0);
    close(pd[1]);
    //EXECUTE_COMMAND(command);
}

void REDIRECT_NO_PIPE(string input)
{
    string com;
    char  *command[1000];
    int i=0;
    char input_source[1000];
    char output_source[1000];
    for(int i=0;i<1000;i++)
    {
        command[i]='\0';
    }
    vector<string> space_split;
    vector<string>::iterator over_space;
    com=PARSE_REDIRECT(input);
    space_split=PARSE_STRING(com,' ');
    for(over_space=space_split.begin();over_space!=space_split.end();over_space++)
    {
        if((*over_space).compare("<")==0)
        {
            strcpy(input_source,(*(over_space+1)).c_str());
        }
        else if((*over_space).compare(">")==0)
        {
            strcpy(output_source,(*(over_space+1)).c_str());
        }
    }
    for(over_space=space_split.begin();over_space!=space_split.end();over_space++)
    {
        if((*over_space).compare("<")==0 || (*over_space).compare(">")==0)
        {
            over_space=over_space+1;
        }
        else
        {
            command[i]=new char[1000];
            strcpy(command[i],(*over_space).c_str());
            i++;
        }
    }
    if(strlen(input_source)!=0)
    {
        int fd0 = open(input_source,O_RDONLY);
        dup2(fd0, STDIN_FILENO);
        close(fd0);
    }
    if (strlen(output_source)!=0)
    {
        int fd1 = creat(output_source, 0666) ;
        dup2(fd1, STDOUT_FILENO);
        close(fd1);
    }
    execvp(command[0],command);
    abort();
}