/*
 * Copyright (C) 2015-2017 Alibaba Group Holding Limited
 */

#include "internal/sal_sockets_internal.h"

/* Here for now until needed in other places in lwIP */
#ifndef isprint
#define in_range(c, lo, up)  ((u8_t)c >= lo && (u8_t)c <= up)
#define isprint(c)           in_range(c, 0x20, 0x7f)
#define isdigit(c)           in_range(c, '0', '9')
#define isxdigit(c)          (isdigit(c) || in_range(c, 'a', 'f') || in_range(c, 'A', 'F'))
#define islower(c)           in_range(c, 'a', 'z')
#define isspace(c)           (c == ' ' || c == '\f' || c == '\n' || c == '\r' || c == '\t' || c == '\v')
#endif

/**
 * Check whether "cp" is a valid ascii representation
 * of an Internet address and convert to a binary address.
 * Returns 1 if the address is valid, 0 if not.
 * This replaces inet_addr, the return value from which
 * cannot distinguish between failure and a local broadcast address.
 *
 * @param cp IP address in ascii representation (e.g. "127.0.0.1")
 * @param addr pointer to which to save the ip address in network order
 * @return 1 if cp could be converted to addr, 0 on failure
 */
int
ip4addr_aton(const char *cp, ip4_addr_t *addr)
{
    u32_t val;
    u8_t base;
    char c;
    u32_t parts[4];
    u32_t *pp = parts;

    c = *cp;
    for (;;) {
        /*
         * Collect number up to ``.''.
         * Values are specified as for C:
         * 0x=hex, 0=octal, 1-9=decimal.
         */
        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)) {
                val = (val * base) + (int)(c - '0');
                c = *++cp;
            } else if (base == 16 && isxdigit(c)) {
                val = (val << 4) | (int)(c + 10 - (islower(c) ? 'a' : 'A'));
                c = *++cp;
            } else {
                break;
            }
        }
        if (c == '.') {
            /*
             * Internet format:
             *  a.b.c.d
             *  a.b.c   (with c treated as 16 bits)
             *  a.b (with b treated as 24 bits)
             */
            if (pp >= parts + 3) {
                return 0;
            }
            *pp++ = val;
            c = *++cp;
        } else {
            break;
        }
    }
    /*
     * Check for trailing characters.
     */
    if (c != '\0' && !isspace(c)) {
        return 0;
    }
    /*
     * Concoct the address according to
     * the number of parts specified.
     */
    switch (pp - parts + 1) {

        case 0:
            return 0;       /* initial nondigit */

        case 1:             /* a -- 32 bits */
            break;

        case 2:             /* a.b -- 8.24 bits */
            if (val > 0xffffffUL) {
                return 0;
            }
            if (parts[0] > 0xff) {
                return 0;
            }
            val |= parts[0] << 24;
            break;

        case 3:             /* a.b.c -- 8.8.16 bits */
            if (val > 0xffff) {
                return 0;
            }
            if ((parts[0] > 0xff) || (parts[1] > 0xff)) {
                return 0;
            }
            val |= (parts[0] << 24) | (parts[1] << 16);
            break;

        case 4:             /* a.b.c.d -- 8.8.8.8 bits */
            if (val > 0xff) {
                return 0;
            }
            if ((parts[0] > 0xff) || (parts[1] > 0xff) || (parts[2] > 0xff)) {
                return 0;
            }
            val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
            break;
        default:
            SAL_ASSERT("unhandled", 0);
            break;
    }
    if (addr) {
        ip4_addr_set_u32(addr, sal_htonl(val));
    }
    return 1;
}

/**
 * Same as ipaddr_ntoa, but reentrant since a user-supplied buffer is used.
 *
 * @param addr ip address in network order to convert
 * @param buf target buffer where the string is stored
 * @param buflen length of buf
 * @return either pointer to buf which now holds the ASCII
 *         representation of addr or NULL if buf was too small
 */
char *
ip4addr_ntoa_r(const ip4_addr_t *addr, char *buf, int buflen)
{
    u32_t s_addr;
    char inv[3];
    char *rp;
    u8_t *ap;
    u8_t rem;
    u8_t n;
    u8_t i;
    int len = 0;

    s_addr = ip4_addr_get_u32(addr);

    rp = buf;
    ap = (u8_t *)&s_addr;
    for (n = 0; n < 4; n++) {
        i = 0;
        do {
            rem = *ap % (u8_t)10;
            *ap /= (u8_t)10;
            inv[i++] = '0' + rem;
        } while (*ap);
        while (i--) {
            if (len++ >= buflen) {
                return NULL;
            }
            *rp++ = inv[i];
        }
        if (len++ >= buflen) {
            return NULL;
        }
        *rp++ = '.';
        ap++;
    }
    *--rp = 0;
    return buf;
}

/**
 * Convert numeric IP address into decimal dotted ASCII representation.
 * returns ptr to static buffer; not reentrant!
 *
 * @param addr ip address in network order to convert
 * @return pointer to a global static (!) buffer that holds the ASCII
 *         representation of addr
 */
char *
ip4addr_ntoa(const ip4_addr_t *addr)
{
    static char str[SAL_SOCKET_IP4_ADDR_LEN];
    return ip4addr_ntoa_r(addr, str, SAL_SOCKET_IP4_ADDR_LEN);
}

/**
 * Ascii internet address interpretation routine.
 * The value returned is in network order.
 *
 * @param cp IP address in ascii representation (e.g. "127.0.0.1")
 * @return ip address in network order
 */
in_addr_t
ipaddr_addr(const char *cp)
{
    ip4_addr_t val;

    if (ip4addr_aton(cp, &val)) {
        return ip4_addr_get_u32(&val);
    }
    return (IPADDR_NONE);
}