Simple c99 argv parser with zero memory allocation
args is very simple, it allocates no memory and is only a single function call!
First, create the meta info for the args you want.
enum ArgID {
ArgID_HELP,
ArgID_VERSION,
ArgID_FILE,
};
const struct ArgsMeta metas[] = {
{
.key = "help",
.id = ArgID_HELP,
.type = ArgsValueType_NONE,
.single = 'h'
},
{
.key = "version",
.id = ArgID_VERSION,
.type = ArgsValueType_NONE,
.single = 'v'
},
{
.key = "file",
.id = ArgID_FILE,
.type = ArgsValueType_STR,
.single = 'f'
},
};Next, we need to setup our output data.
NOTE: The number of entries in this array MUST be the same size as the ArgsMeta array we created above!
#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
struct Argsdata data[ARRAY_SIZE(metas)] = {0};
// this is how many entires are filled by the parser!
unsigned data_count = {0};Finally, we can call the parse function!
const enum ArgsResult result = args_parse(
1, argc, argv,
metas, ARRAY_SIZE(metas),
data, &data_count
);NOTE: You might notice that we pass a 1 as the first param. That's just the index that we want to start from.
Usually, argv[0] is the path of the program, so we can skip then, hence passing 1, so we start from argv[1]
The return value of the parser is an enum. in general, 0 == OK, any negative number is an error, any positive number is OK but with with a warning.
switch (result) {
case ArgsResult_UNWANTED_VALUE:
case ArgsResult_BAD_VALUE:
case ArgsResult_MISSING_VALUE:
case ArgsResult_ERROR:
printf("Args Error: %d\n", result);
return -1;
case ArgsResult_OK:
case ArgsResult_EXTRA_ARGS:
break;
}The filled out data struct looks like this:
struct Argsdata {
const char* key; // key, not always NULL terminated
unsigned key_len; // actual length of the key
union ArgsValue value; // union of value types
int id; // your ID that you set for the key
};where value is a union of types:
union ArgsValue {
const char* s;
long long i;
double d;
bool b;
};You can loop now through the struct Argsdata array we created earlier, here's an example
for (unsigned i = 0; i < data_count; ++i) {
switch (data[i].id) {
case ArgID_HELP:
printf("key: %.*s\n", data[i].key_len, data[i].key);
break;
case ArgID_VERSION:
printf("key: %.*s\n", data[i].key_len, data[i].key);
break;
case ArgID_FILE:
printf("key: %.*s value: %s\n", data[i].key_len, data[i].key, data[i].value.s);
break;
}
}The full example can be seen here