CODEWITHSUNDEEP
c++
aripod
aripod

Reputation: 57

Set size of boost::shared_array after declaration

I have at the beginning of the code boost::shared_array<uint8_t> buffer(new uint8_t[fileSize]);. I want to change that as size will be read from a file. Therefore, how can I just declare boost::shared_array<uint8_t> buffer and allocate the size after I read it?

I am reading the file with:

    size_t fileSize;
    union size{
        uint8_t size_arr[4];
        uint32_t size;
    } size;
    if (myfile.is_open()){
        while ( getline (myfile,line) ){
            if(lineNum==1)
                size.size_arr[0] = strtoul(line.c_str(), 0 , 16);
            if(lineNum==2)
                size.size_arr[1] = strtoul(line.c_str(), 0 , 16);
            if(lineNum==3)
                size.size_arr[2] = strtoul(line.c_str(), 0 , 16);
            if(lineNum==4) {
                size.size_arr[3] = strtoul(line.c_str(), 0 , 16);
                fileSize = size.size;
                //boost::shared_array<uint8_t> buffer(new uint8_t[stringFromFile_size]); //CANNOT be done here
            }
            if(lineNum>=5)
                size.size_arr[lineNum-1] = strtoul(line.c_str(), 0 , 16);
            lineNum++;
        }

        myfile.close();
    }

Of course if I declare it in the if for lineNum==4 I cannot use buffer outside the while loop which is the goal.

Thank you for the help.

Upvotes: 0

Views: 202

Answers (1)

Aykhan Hagverdili
Aykhan Hagverdili

Reputation: 29985

Use std::unique_ptr or std::shared_ptr:

std::unique_ptr<uint8_t[]> buffer; // note []
// std::shared_ptr<uint8_t[]> buffer; 

// get size 
size_t sz = ...;

buffer.reset(new uint8_t[sz]); // allocate memory

Upvotes: 1

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