mbed-os/features/frameworks/nanostack-libservice/source/libip4string/stoip4.c

76 lines
2.5 KiB
C

/*
* Copyright (c) 2014-2018, Pelion and affiliates.
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <string.h>
#include <stdlib.h>
#include <stdint.h>
#include "common_functions.h"
#include "ip4string.h"
/**
* Convert numeric IPv4 address string to a binary.
* \param ip4addr IPv4 address in string format.
* \param len Length of IPv4 string, maximum of 16..
* \param dest buffer for address. MUST be 4 bytes.
* \return boolean set to true if conversion succeded, false if it didn't
*/
bool stoip4(const char *ip4addr, size_t len, void *dest)
{
uint8_t *addr = dest;
if (len > 16) { // Too long, not possible
return false;
}
uint_fast8_t stringLength = 0, byteCount = 0;
//Iterate over each component of the IP. The exit condition is in the middle of the loop
while (true) {
//No valid character (IPv4 addresses don't have implicit 0, that is x.y..z being read as x.y.0.z)
if (stringLength == len || ip4addr[stringLength] < '0' || ip4addr[stringLength] > '9') {
return false;
}
//For each component, we convert it to the raw value
uint_fast16_t byte = 0;
while (stringLength < len && ip4addr[stringLength] >= '0' && ip4addr[stringLength] <= '9') {
byte *= 10;
byte += ip4addr[stringLength++] - '0';
//We go over the maximum value for an IPv4 component
if (byte > 0xff) {
return false;
}
}
//Append the component
addr[byteCount++] = (uint8_t) byte;
//If we're at the end, we leave the loop. It's the only way to reach the `true` output
if (byteCount == 4) {
break;
}
//If the next character is invalid, we return false
if (stringLength == len || ip4addr[stringLength++] != '.') {
return false;
}
}
return stringLength == len || ip4addr[stringLength] == '\0';
}