ddbencode

ddbencode is a library implements a MIT-licenced "bencode" encoder and decoder. It comes with a comprehensive test suite to ensure correctness.

Requirements

ddbencode requires a C99-compliant compiler. It also depends on CObject, a minimalistic reference-counting library that makes memory management in C a lot easier.

Building ddbencode requires rake (Ruby make), although it should be rather easy to build the library and applications without rake.

Running the unit tests requires uctest which is a simple C unit testing library. The rakefile assumes that uctest is placed inside the "vendor" directory.

The CObject and uctest dependencies can be fetched automagically by issuing the fetch_dependencies rake task.

Usage

See the source documentation for sample usage.

Examples

String creation example:

BEString *string = BEStringCreate(
	"foo", 3
);

List creation example:

BEList *list = BEListCreate(
	4,                   // number of list entries
	BE_STRING,  string,  // entry 0
	BE_INTEGER, 123,     // entry 1
	BE_LIST,    someList // entry 2
);

Dictionary creation example:

BEDictionary *dictionary = BEDictionaryCreate(
	4                                // number of dictionary entries
	"foo",  BE_STRING,     string,   // entry 0
	"bar",  BE_INTEGER,    123,      // entry 1
	"baz",  BE_LIST,       someList, // entry 2
	"quux", BE_DICTIONARY, someDict  // entry 3
);

Encoding example:

BEList *list = BEListCreate(...);

void *data;
size_t dataLength;

BEListEncode(list, &data, &dataLength);

Decoding example:

bool success;

BEType type;

BEString *string = NULL;
int integer = 0;
BEList *list = NULL;
BEDictionary *dictionary = NULL;

size_t usedLength = 0;

success = BEDecode(
	"le", 2,                               // the data and its length
	&type,                                 // the type of the decoded item
	&string, &integer, &list, &dictionary, // the decoded item
	&usedLength                            // the amount of consumed bytes
);

if(success)
{
	puts("successfully decoded");
	if(type == BE_STRING)
		printf("We have a string: %s\n", string);
	else if(type == BE_INTEGER)
		printf("We have an integer: %s\n", integer);
	// etc...
}

Tests

ddbencode comes with a comprehensive test suite to ensure the correctness of its implementation. Issue the test rake task in order to run the test suite. Running the test suite should not cause any failures to be reported; if one or more tests fail, please contact me (see below).

Contact

You can reach me (Denis Defreyne) at denis.defreyne@stoneship.org.

References

• BitTorrent specification at http://wiki.theory.org/BitTorrentSpecification