adler32.cpp File Reference

#include <cstddef>
#include <cstdint>
#include <limits>
#include <cmath>
#include <iostream>

Go to the source code of this file.

Functions
void	cpp_adler32 (const unsigned char *data, int len, int *result)
void	test_cpp_adler32 ()

Variables
constexpr uint32_t	ROOT = 65521

Function Documentation

cpp_adler32()

void cpp_adler32	(	const unsigned char *	data,
		int	len,
		int *	result )

Definition at line 30 of file adler32.cpp.

                                                                              {
    uint32_t a = 1, b = 0;
    for (size_t i = 0; i < len; ++i) {
        a = (a + data[i]) % ROOT;
        b = (b + a) % ROOT;
    }
    // cast the result into an int (32  bits)
    uint32_t r = (b << 16) | a;
    *result =  *reinterpret_cast<int32_t*>(&r);
}

test_cpp_adler32()

void test_cpp_adler32

(

)

Definition at line 44 of file adler32.cpp.

{
    double * data = new double[100];
    double * data2 = new double[100];
 
    for (int i = 0; i < 100; ++i) {
        data[i] = i;
        data2[i] = i;
    }
 
    // find the next representable value of data2[50]
    data2[50] = std::nextafter(data2[50], std::numeric_limits<double>::max());
 
    int result1, result2;
    cpp_adler32(reinterpret_cast<unsigned char*>(data), 100 * sizeof(double), &result1);
    cpp_adler32(reinterpret_cast<unsigned char*>(data2), 100 * sizeof(double), &result2);
    //print the two values
    std::cout << "result1: " << result1 << std::endl;
    std::cout << "result2: " << result2 << std::endl;
 
}

Variable Documentation

ROOT

uint32_t ROOT = 65521

constexpr

Definition at line 28 of file adler32.cpp.