Cómo leer datos binarios y convertirlos en caracteres sin signo (C++)

Question

Tengo un archivo de imagen sin formato que se guarda en datos binarios (sin codificación). Quiero leer en el archivo y convertir los valores a un char sin signo. Pero no estoy seguro de cómo empezar a hacer esto. Cada archivo contiene 640x480 bytes. Cada píxel es de 8bits.

He utilizado la página de ayuda de C++ aquí: http://www.cplusplus.com/doc/tutorial/files/, sin embargo, cuando estoy couting los datos, parece mostrar los mismos caracteres binarios/no legibles por humanos. ¿Puede alguien por favor asesorar? Aquí está mi código hasta ahora:

#include <iostream> 
    #include <fstream> 
    using namespace std; 

ifstream::pos_type size; 
char * memblock; 

int main() { 
    ifstream file ("imageData.raw", ios::in|ios::binary|ios::ate); 
    if (file.is_open()) 
    { 
    size = file.tellg(); 
    memblock = new char [size]; 
    file.seekg (0, ios::beg); 
    file.read (memblock, size); 

    cout << "the complete file content is in memory"; 

    for (int l=0; l<size; l++){ 
    cout << " memblock[] is = " << (unsigned char)memblock[l] << " index was l = " << l << endl; 
    } 

    file.close(); 


    delete[] memblock; 
    } 
    else cout << "Unable to open file"; 
    return 0; 
} 

Aquí se muestra una captura de la salida:

memblock[] is = ▀ index was l = 2937 
memblock[] is = E index was l = 2938 
memblock[] is = τ index was l = 2939 
memblock[] is = C index was l = 2940 
memblock[] is = ┘ index was l = 2941 
memblock[] is = B index was l = 2942 
memblock[] is = ╬ index was l = 2943 
memblock[] is = D index was l = 2944 
memblock[] is = ┼ index was l = 2945 
memblock[] is = C index was l = 2946 
memblock[] is = ╝ index was l = 2947 
memblock[] is = B index was l = 2948 
memblock[] is = ┤ index was l = 2949 
memblock[] is = B index was l = 2950 
memblock[] is = ¿ index was l = 2951 
memblock[] is = > index was l = 2952 
memblock[] is = í index was l = 2953 
memblock[] is = ; index was l = 2954 
memblock[] is = £ index was l = 2955 
memblock[] is = 6 index was l = 2956 
memblock[] is = á index was l = 2957 
memblock[] is = 4 index was l = 2958 
memblock[] is = Ñ index was l = 2959 
memblock[] is = 7 index was l = 2960 
memblock[] is = ╡ index was l = 2961 

Answer 1

unsigned char* memblock; // change declaration of memblock 

... 

memblock = new unsigned char[size]; // change to unsigned char 
file.seekg (0, ios::beg); 
file.read ((char*)memblock, size); // cast to a char* to give to file.read 

Para imprimir los valores numéricos en lugar de caracteres, emitidos a un int antes de imprimir.

(int) memblock[l]