max80_fw/esp32/max80/IP4.h

#pragma once

#include "common.h"
#include <WiFi.h>
#include <lwip/inet.h>
#include <esp_wifi.h>

//
// There are no less than 3 different types for IP addresses used
// by different APIs. This class attempts to unify them to mask the
// differences.
//
class IP4 {
private:
    union {
	uint8_t b[4];
	uint32_t l;
    };
    // assumes gcc
    static constexpr uint32_t netswap(uint32_t v) {
#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
	return v;
#else
	return __builtin_bswap32(v);
#endif
    }
    static constexpr uint32_t hostmask(unsigned int n) {
	return n >= 32 ? 0 : netswap(((uint32_t)1 << n)-1);
    }
public:
    constexpr IP4() : l{0} { }
    constexpr IP4(nullptr_t) : l{0} { }
    constexpr IP4(int ll) : l{(uint32_t)ll} { }
    constexpr IP4(uint32_t ll) : l{ll} { }
    constexpr IP4(uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3) :
	b{b0,b1,b2,b3} { }
    IP4(const IPAddress & ip) : l{ip} { }
    constexpr IP4(const ip_addr_t & ip) :
	l{ip.type == IPADDR_TYPE_V4 ? ip.u_addr.ip4.addr : 0} { }
    constexpr IP4(const esp_ip_addr_t & ip) :
	l{ip.type == IPADDR_TYPE_V4 ? ip.u_addr.ip4.addr : 0} { }
    constexpr IP4(const IP4 &nip, const IP4 &hip, unsigned int n) :
	l{(nip.l & ~hostmask(n)) | (hip.l & hostmask(n))} { }
    constexpr IP4(const IP4 &nip, const IP4 &hip, const IP4 &mask) :
	l{(nip.l & ~mask.l) | (hip.l & mask.l)} { }
    IP4(const char *str);

    operator uint32_t () const { return l; }
    operator IPAddress () const { return IPAddress(l); }
    constexpr operator ip_addr_t () const {
	return ip_addr_t {
	    .u_addr = {.ip4 = {.addr = l}},
	    .type = IPADDR_TYPE_V4
	};
    }
    constexpr operator esp_ip_addr_t () const {
	return esp_ip_addr_t {
	    .u_addr = {.ip4 = {.addr = l}},
	    .type = IPADDR_TYPE_V4
	};
    }

    //
    // XXX: for C++20, this should implement operator <=>.
    //
    constexpr operator bool () const { return l != 0; }
    constexpr bool operator ! () const { return l == 0; }
    constexpr bool operator == (const IP4 &b) const { return l == b.l; }
    constexpr bool operator != (const IP4 &b) const { return l != b.l; }

    constexpr bool operator < (const IP4 &b) const {
	return netswap(l) < netswap(b.l);
    }
    constexpr bool operator >= (const IP4 &b) const {
	return netswap(l) >= netswap(b.l);
    }
    constexpr bool operator <= (const IP4 &b) const {
	return netswap(l) <= netswap(b.l);
    }
    constexpr bool operator > (const IP4 &b) const {
	return netswap(l) > netswap(b.l);
    }
#ifdef __cpp_impl_three_way_comparison
    constexpr auto operator <=> (const IP4 &b) const {
	return netswap(l) <=> netswap(b.l);
    }
#endif

    constexpr IP4 operator & (const IP4 &b) const { return IP4(l & b.l); }
    constexpr IP4 operator | (const IP4 &b) const { return IP4(l | b.l); }
    constexpr IP4 operator ^ (const IP4 &b) const { return IP4(l ^ b.l); }
    constexpr IP4 operator ~ () const { return IP4(~l); }
    constexpr IP4 operator / (unsigned int n) const {
	return IP4(l & ~hostmask(n));
    }
    constexpr IP4 operator % (unsigned int n) const {
	return IP4(l & hostmask(n));
    }
    constexpr IP4 operator + (uint32_t n) const {
	return IP4(netswap(netswap(l) + n));
    }
    constexpr IP4 operator - (uint32_t n) const {
	return IP4(netswap(netswap(l) - n));
    }
    constexpr int32_t operator - (const IP4 &b) const {
	return netswap(l) - netswap(b.l);
    }
    constexpr uint8_t operator [] (size_t n) const { return b[n]; }
    uint8_t & operator [] (size_t n) { return b[n]; }

    const char *cstr();
};

constexpr IP4 null_ip((uint32_t)0);
constexpr IP4 any_ip(~(uint32_t)0);