getline with unsigned char string - c++

Question

So, I did some searching for why my compiler gives an error saying:
49 ~\C++\SHA-1\main.cpp invalid conversion from `unsigned char*' to `char*'
And I found out that you cannot convert between unsigned char to char because they are completely different types. So this lead me to the problem of needing a getline function for and unsigned char string in my code.
#include <iostream>
#include <stdint.h>
using namespace std;
uint32_t rotl( uint32_t value, int shift)
{
if ((shift &= sizeof(value)*8 - 1) == 0) return value;
return (value << shift) | (value >> (sizeof(value)*8 - shift));
}
uint32_t rotr( uint32_t value, int shift)
{
if ((shift &= sizeof(value)*8 - 1) == 0) return value;
return (value >> shift) | (value << (sizeof(value)*8 - shift));
}
int textInput();
int hexInput();
int binInput();
unsigned char message[64];
int SHA_1();
int main()
{
int selection;
cout<<"Select Input type:\n\n\t1. Text String\n\t2. Hex String\n\t3. Binary String\n";
cin>>selection;
cin.ignore();
switch(selection)
{
case 1: textInput(); break;
case 2: hexInput(); break;
case 3: binInput(); break;
}
SHA_1();
cout<<"\ndone";
cin.get();
return 0;
}
int textInput()
{
unsigned char input[63] = {0};
cout<<"Enter a text string to be hashed\n\n";
cin.getline(input, 62, '\n');
cin.ignore();
for(int x = 0; x <= 63; x++)
{
//cout<<x<<"\n";
if (input[x] == 0x00)
{
message[x] = 0x00000080;
message[63] = x; //This might be wrong.
//cout<<std::hex<<message;
break;
}
else message[x] = input[x];
}
return 0;
}
int hexInput()
{
return 0;
}
int binInput()
{
return 0;
}
int SHA_1()
{
uint32_t h0 = 0x67452301;
uint32_t h1 = 0xEFCDAB89;
uint32_t h2 = 0x98BADCFE;
uint32_t h3 = 0x10325476;
uint32_t h4 = 0xC3D2E1F0;
uint32_t a;
uint32_t b;
uint32_t c;
uint32_t d;
uint32_t e;
uint32_t f;
uint32_t k;
uint32_t temp;
uint32_t w[80];
/*for( int m = 0; m <= 63; m++)
{
cout<<"message["<<m<<"]="<<std::hex<<int(message[m])<<std::dec<<"\n";
}*/
for( int i = 0; i <= 15; i++)
{
w[i] = ((message[(i*4)] << 24) | (message[(i*4) + 1] << 16) | (message[(i*4) + 2] << 8) | (message[(i*4) + 3]));
//cout<<"W["<<i<<"]="<<std::hex<<w[i]<<std::dec<<"\n";
}
for( int i = 16; i <= 79; i++)
{
w[i] = rotl((w[i - 3] ^ w[i - 8] ^ w[i - 14] ^ w[i - 16]), 1);
}
a = h0;
b = h1;
c = h2;
d = h3;
e = h4;
for(int iteration = 0; iteration <= 79; iteration++)
{
if((0 <= iteration) && (iteration <= 19))
{
f = ((b & c) | ((~b) & d));
k = 0x5A827999;
}
else if((20 <= iteration) && (iteration <= 39))
{
f = (b ^ c ^ d);
k = 0x6ED9EBA1;
}
else if((40 <= iteration) && (iteration <= 59))
{
f = ((b & c) | (b & d) | (c & d));
k = 0x8F1BBCDC;
}
else if((60 <= iteration) && (iteration <= 79))
{
f = (b ^ c ^ d);
k = 0xCA62C1D6;
}
temp = (rotl( a, 5) + f + e + k + w[iteration]);
e = d;
d = c;
c = rotl( b, 30);
b = a;
a = temp;
}
h0 = h0 + a;
h1 = h1 + b;
h2 = h2 + c;
h3 = h3 + d;
h4 = h4 + e;
cout<<hex<<h0<<" "<<h1<<" "<<h2<<" "<<h3<<" "<<h4;
return 0;
}
If anyone could give me some suggestions that would be helpful.
Thanks

Answer 1

This is related to strict-aliasing constraints: you're not permitted to reference an unsigned char array via a char pointer.
#include <iostream>
using namespace std;
void aliasing_fun(char* arr) {
arr[0] = 42;
}
int main() {
unsigned char arr[10] = {0};
aliasing_fun(arr); // Not allowed
return 0;
}
http://ideone.com/r4OVZi
You might cast your array to char* in order to do that.

Answer 2

Cast your array to (char *) when calling getline:
getline((char *)input, ...);