我目前正在學習C.我的生态系統包括Espressif ESP-32微控制器和Eclipse CDT IDE.
我試圖将一個轉換uint8_t[]為人類可讀的IPv4 address string.到目前為止,我想出了以下代碼:
void app_main() {
uint8_t[] ip = {192, 168, 0, 99};
dump_ip(ip);
}
void dump_ip(const uint8_t *in) {
// ip addresses consist of three dots + terminator '\0'
int size = 4;
// count amount of chars needed for specific ip address
for(int i=0; i<4; i++) {
if(in[i]==0) {
size ++;
} else {
size += ((int)log10(in[i]))+1;
}
}
// allocate memory on heap for an ip address of length 'size'
char *ip_str = (char*)malloc(size*sizeof(char));
// copy ip address parts to char array
int pos = 0;
for(int i=0; i<4; i++) {
if(in[i]==0) {
ip_str[pos] = '0';
pos++;
} else {
char b[4];
itoa(in[i], b, 10);
for(int j=0; j<3; j++) {
if(b[j]!='0') {
ip_str[pos] = b[j];
pos++;
}
}
}
// add dot between ip address parts
if(i<3) {
ip_str[pos] = '.';
pos++;
}
}
// add terminator at end of string
ip_str[pos] = '\0';
// print to uart interface
uart_send(ip_str);
// release allocated heap memory
free(ip_str);
}
在使用不同的IP陣列進行測試時,我得到以下結果:
uint8_t[] ip = {192, 168, 0, 99}; => "192.168.0.99" => OK
uint8_t[] ip = {192, 168, 1, 99}; => "192.168.1" => FAILED
uint8_t[] ip = {192, 168, 10, 99}; => "192.168.1" => FAILED
uint8_t[] ip = {10, 10, 10, 10}; => "1" => FAILED
// etc. etc. etc.
我究竟做錯了什麼？有沒有更優雅的方法來實作這一目标？