wstationd/src/imei.c

#include <stdlib.h>
#include <inttypes.h>
#include "imei.h"


imei_set* imei_set_new(size_t capacity)
{
	imei_set* set = (imei_set*)malloc(
		sizeof(imei_set) + (capacity * sizeof(uint64_t))
	);
	if(set == NULL) return NULL;

	set->sz = 0;
	set->cp = capacity;

	return set;
}


// This is not efficient at all. It could be made vastly
// more efficient by having imei_set_add() insert in order
// and then implementing a binary search algorithm here
int imei_set_search(imei_set* set, uint64_t imei)
{
	for(size_t i = 0; i < set->sz; i++){
		if(set->imeis[i] == imei) return 1;
	}
	return 0;
}


void imei_set_free(imei_set *set){
	if(set != NULL) free(set);
}


int imei_set_add(imei_set** set, uint64_t imei)
{
	// Don't allow out-of-bounds imeis
	if(imei == UINT64_MAX) return 1;

	// Don't allow duplicate entries
	if(imei_set_search(*set, imei)) return 2;

	// If the set is full, expand it
	if((*set)->sz == (*set)->cp){
		imei_set* nset = realloc(
			*set, sizeof(imei_set) + (((*set)->cp + 1000) * sizeof(uint64_t))
		);
		if(nset == NULL) return 1;
		nset->cp += 1000;
		(*set) = nset;
	}

	(*set)->imeis[(*set)->sz] = imei;
	(*set)->sz++;

	return 0;
}


uint64_t imei_uint64(unsigned char *imei, size_t sz)
{
	// IMEI's are always 15 bytes in length
	if(sz != 15) return UINT64_MAX;

	uint64_t r = 0;
	for(int i = 0; i < 15; i++){
		// If any byte in the IMEI isn't a proper digit,
		// return an error - UINT64_MAX is used because
		// an imei will only use 60 bits, so the
		// max for a 64-bit unsigned int is out of bounds.
		if(imei[i] < '0' || imei[i] > '9') return UINT64_MAX;

		r = (r<<4) + (imei[i] - '0');
	}

	return r;
}