soc_inet_aton.c

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#include "soc_common.h"
#include <arpa/inet.h>
#include <ctype.h>
#include <stdint.h>

int inet_aton(const char *cp, struct in_addr *inp)
{
    int      base;
    uint32_t val;
    int      c;
    char     bytes[4];
    size_t   num_bytes = 0;

    c = *cp;
    for(;;) {
        if(!isdigit(c)) return 0;

        val = 0;
        base = 10;
        if(c == '0') {
            c = *++cp;
            if(c == 'x' || c == 'X') {
                base = 16;
                c = *++cp;
            }
            else base = 8;
        }

        for(;;) {
            if(isdigit(c)) {
                if(base == 8 && c >= '8') return 0;
                val *= base;
                val += c - '0';
                c    = *++cp;
            }
            else if(base == 16 && isxdigit(c)) {
                val *= base;
                val += c + 10 - (islower(c) ? 'a' : 'A');
                c    = *++cp;
            }
            else break;
        }

        if(c == '.') {
            if(num_bytes > 3) return 0;
            if(val > 0xFF) return 0;
            bytes[num_bytes++] = val;
            c = *++cp;
        }
        else break;
    }

    if(c != 0) return 0;

    switch(num_bytes) {
    case 0:
        return 0;

    case 1:
        break;

    case 2:
        if(val > 0xFFFFFF) return 0;
        val |= bytes[0] << 24;
        break;

    case 3:
        if(val > 0xFFFF) return 0;
        val |= bytes[0] << 24;
        val |= bytes[1] << 16;
        break;

    case 4:
        if(val > 0xFF) return 0;
        val |= bytes[0] << 24;
        val |= bytes[1] << 16;
        val |= bytes[2] << 8;
        break;
    }

    if(inp)
        inp->s_addr = htonl(val);

    return 1;
}