This library contains checksum functions and classes.

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CMake is used to build this library, which is exported as a library target called checksum. The header is added as:

#include "checksum/checksum.h"

The library can be also be compiled stand-alone using the CMake idiom of creating a build directory and then, from within that directory issuing:

cmake ..
make

This will build the library, an example executable called checksum_example, and an executable for testing using the Google Test framework, called checksum_test. The example executable source file is located at examples/checksum_example.cc.

This library is within the namespace bfs.

This class implements a Fletcher16 checksum.

Fletcher16() Creates a Fletcher16 object and initializes the checksum states.

bfs::Fletcher16 chk;

uint16_t Compute(uint8_t *data, std::size_t len) Initializes the checksum states and computes the checksum in a single pass, given a pointer to an array of the data and the length of the array. The result is returned as a 16 bit unsigned integer.

uint8_t test[] = {'a','b','c','d','e'};
uint16_t result = chk.Compute(test, sizeof(test));
std::cout << result << std::endl;  // 51440

uint16_t Update(uint8_t *data, std::size_t len) Computes the checksum given a pointer to an array of the data and the length of the array. The result is returned as a 16 bit unsigned integer. Note that this method does not reset the checksum states, enabling it to be used iteratively.

uint8_t test[] = {'a','b','c','d','e'};
for (std::size_t i = 0; i < sizeof(test); i++) {
   result = chk.Update(&test[i], 1);
}
std::cout << result << std::endl;  // 51440

void Reset() This method resets the checksum states. It should be used in conjunction with the Update method to reset states in between different checksum computations.

uint8_t test[] = {'a','b','c','d','e'};
for (std::size_t i = 0; i < sizeof(test); i++) {
   result = chk.Update(&test[i], 1);
}
std::cout << result << std::endl;  // 51440
chk.Reset();
uint8_t test2[] = {'a','b','c','d','e','f','g','h'};
for (std::size_t i = 0; i < sizeof(test2); i++) {
   result = chk.Update(&test2[i], 1);
}
std::cout << result << std::endl;  // 1575