stoip4.c

00001 /*
00002  * Copyright (c) 2014-2018 ARM Limited. All rights reserved.
00003  * SPDX-License-Identifier: Apache-2.0
00004  * Licensed under the Apache License, Version 2.0 (the License); you may
00005  * not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  * http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an AS IS BASIS, WITHOUT
00012  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 #include <string.h>
00017 #include <stdlib.h>
00018 #include <stdint.h>
00019 #include "common_functions.h"
00020 #include "ip4string.h"
00021 
00022 /**
00023  * Convert numeric IPv4 address string to a binary.
00024  * \param ip4addr IPv4 address in string format.
00025  * \param len Length of IPv4 string, maximum of 16..
00026  * \param dest buffer for address. MUST be 4 bytes.
00027  * \return boolean set to true if conversion succeded, false if it didn't
00028  */
00029 bool stoip4(const char *ip4addr, size_t len, void *dest)
00030 {
00031     uint8_t *addr = dest;
00032 
00033     if (len > 16) { // Too long, not possible
00034         return false;
00035     }
00036 
00037     uint_fast8_t stringLength = 0, byteCount = 0;
00038 
00039     //Iterate over each component of the IP. The exit condition is in the middle of the loop
00040     while (true) {
00041 
00042         //No valid character (IPv4 addresses don't have implicit 0, that is x.y..z being read as x.y.0.z)
00043         if (stringLength == len || ip4addr[stringLength] < '0' || ip4addr[stringLength] > '9') {
00044             return false;
00045         }
00046 
00047         //For each component, we convert it to the raw value
00048         uint_fast16_t byte = 0;
00049         while (stringLength < len && ip4addr[stringLength] >= '0' && ip4addr[stringLength] <= '9') {
00050             byte *= 10;
00051             byte += ip4addr[stringLength++] - '0';
00052 
00053             //We go over the maximum value for an IPv4 component
00054             if (byte > 0xff) {
00055                 return false;
00056             }
00057         }
00058 
00059         //Append the component
00060         addr[byteCount++] = (uint8_t) byte;
00061 
00062         //If we're at the end, we leave the loop. It's the only way to reach the `true` output
00063         if (byteCount == 4) {
00064             break;
00065         }
00066 
00067         //If the next character is invalid, we return false
00068         if (stringLength == len || ip4addr[stringLength++] != '.') {
00069             return false;
00070         }
00071     }
00072 
00073     return stringLength == len || ip4addr[stringLength] == '\0';
00074 }