os2_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 "mbed_version.h"
00017 
00018 #if MBED_MAJOR_VERSION == 2
00019 
00020 #include <string.h>
00021 #include <stdlib.h>
00022 #include <stdint.h>
00023 #include "common_functions.h"
00024 #include "ip4string.h"
00025 
00026 /**
00027  * Convert numeric IPv4 address string to a binary.
00028  * \param ip4addr IPv4 address in string format.
00029  * \param len Length of IPv4 string, maximum of 16..
00030  * \param dest buffer for address. MUST be 4 bytes.
00031  * \return boolean set to true if conversion succeded, false if it didn't
00032  */
00033 bool stoip4(const char *ip4addr, size_t len, void *dest)
00034 {
00035     uint8_t *addr = dest;
00036 
00037     if (len > 16) { // Too long, not possible
00038         return false;
00039     }
00040 
00041     uint_fast8_t stringLength = 0, byteCount = 0;
00042 
00043     //Iterate over each component of the IP. The exit condition is in the middle of the loop
00044     while (true) {
00045 
00046         //No valid character (IPv4 addresses don't have implicit 0, that is x.y..z being read as x.y.0.z)
00047         if (stringLength == len || ip4addr[stringLength] < '0' || ip4addr[stringLength] > '9') {
00048             return false;
00049         }
00050 
00051         //For each component, we convert it to the raw value
00052         uint_fast16_t byte = 0;
00053         while (stringLength < len && ip4addr[stringLength] >= '0' && ip4addr[stringLength] <= '9') {
00054             byte *= 10;
00055             byte += ip4addr[stringLength++] - '0';
00056 
00057             //We go over the maximum value for an IPv4 component
00058             if (byte > 0xff) {
00059                 return false;
00060             }
00061         }
00062 
00063         //Append the component
00064         addr[byteCount++] = (uint8_t) byte;
00065 
00066         //If we're at the end, we leave the loop. It's the only way to reach the `true` output
00067         if (byteCount == 4) {
00068             break;
00069         }
00070 
00071         //If the next character is invalid, we return false
00072         if (stringLength == len || ip4addr[stringLength++] != '.') {
00073             return false;
00074         }
00075     }
00076 
00077     return stringLength == len || ip4addr[stringLength] == '\0';
00078 }
00079 #endif