net.conv: use a pure v implementation instead of C.hton etc (#18226)

vlib/net/conv/README.md

@@ -0,0 +1,14 @@
+## Description:
+
+`net.conv` provides a convenient way to convert number values *to*,
+and *from* the network byte order format (which is always big endian).
+
+When communicating across a network, it is possible that the machines
+use different byte orders, since the host format of each system can
+vary, depending on the CPU, and on most systems, is usually
+little endian.
+
+To avoid mismatches due to that, the network byte order is used by
+convention to send network data in a manner that will be received
+coherently, regardless of the endianness of the sender system and
+the receiver system.

vlib/net/conv/c_default.c.v

@@ -1,9 +0,0 @@
-module conv
-
-#include <arpa/inet.h>
-
-fn C.htonl(host u32) u32
-fn C.htons(host u16) u16
-
-fn C.ntohl(net u32) u32
-fn C.ntohs(net u16) u16

vlib/net/conv/c_windows.c.v

@@ -1,15 +0,0 @@
-module conv
-
-#include <winsock2.h>
-
-#flag -lws2_32
-
-fn C.htonl(host u32) u32
-fn C.htons(host u16) u16
-
-fn C.ntohl(net u32) u32
-fn C.ntohs(net u16) u16
-
-//** These are not supplied with mingw/gcc **
-// fn C.htonll(host u64) u64
-// fn C.ntohll(net u64) u64

vlib/net/conv/conv.c.v

@@ -1,60 +0,0 @@
-module conv
-
-// host to net 32 (htonl)
-pub fn htn32(host u32) u32 {
-	return C.htonl(host)
-}
-
-// host to net 16 (htons)
-pub fn htn16(host u16) u16 {
-	return C.htons(host)
-}
-
-// net to host 32 (ntohl)
-pub fn nth32(host u32) u32 {
-	return C.ntohl(host)
-}
-
-// net to host 16 (ntohs)
-pub fn nth16(host u16) u16 {
-	return C.ntohs(host)
-}
-
-//******************************
-
-struct Bytes {
-mut:
-	first u32
-	last  u32
-}
-
-union LongLong {
-	Bytes
-	ll u64
-}
-
-// host to net 64 (htonll)
-pub fn htn64(host u64) u64 {
-	mut ll := LongLong{
-		ll: host
-	}
-
-	unsafe {
-		ll.first = htn32(ll.first)
-		ll.last = htn32(ll.last)
-	}
-	return unsafe { ll.ll }
-}
-
-// net to host 64 (ntohll)
-pub fn nth64(net u64) u64 {
-	mut ll := LongLong{
-		ll: net
-	}
-
-	unsafe {
-		ll.first = nth32(ll.first)
-		ll.last = nth32(ll.last)
-	}
-	return unsafe { ll.ll }
-}

vlib/net/conv/conv.v

@@ -0,0 +1,66 @@
+module conv
+
+// htn64 converts a the 64 bit value `host` to the net format (htonll)
+pub fn htn64(host u64) u64 {
+	$if little_endian {
+		// vfmt off
+		return (
+			((host >> 56) & 0x00000000_000000FF) | 
+			((host >> 40) & 0x00000000_0000FF00) | 
+			((host >> 24) & 0x00000000_00FF0000) | 
+			((host >> 8)  & 0x00000000_FF000000) |
+			((host << 8)  & 0x000000FF_00000000) | 
+			((host << 24) & 0x0000FF00_00000000) | 
+			((host << 40) & 0x00FF0000_00000000) | 
+			((host << 56) & 0xFF000000_00000000)
+		)
+		// vfmt on
+	} $else {
+		return host
+	}
+}
+
+// htn32 converts the 32 bit value `host` to the net format (htonl)
+pub fn htn32(host u32) u32 {
+	$if little_endian {
+		// vfmt off
+		return (
+			((host >> 24) & 0x0000_00FF) | 
+			((host >> 8)  & 0x0000_FF00) | 
+			((host << 8)  & 0x00FF_0000) | 
+			((host << 24) & 0xFF00_0000)
+		)
+		// vfmt on
+	} $else {
+		return host
+	}
+}
+
+// htn16 converts the 16 bit value `host` to the net format (htons)
+pub fn htn16(host u16) u16 {
+	$if little_endian {
+		// vfmt off
+		return (
+			((host >> 8) & 0x00FF) | 
+			((host << 8) & 0xFF00)
+		)
+		// vfmt on
+	} $else {
+		return host
+	}
+}
+
+// nth64 converts the 64 bit value `net` to the host format (ntohll)
+pub fn nth64(net u64) u64 {
+	return htn64(net)
+}
+
+// nth32 converts the 32 bit value `net` to the host format (ntohl)
+pub fn nth32(net u32) u32 {
+	return htn32(net)
+}
+
+// nth16 converts the 16 bit value `net` to the host format (ntohs)
+pub fn nth16(net u16) u16 {
+	return htn16(net)
+}