alicebob / enum2go Goto Github PK

Export enums from C to Go.

For when you need a bunch of enums from a C header file in Go.

It compiles. Ship it!

Give the header file, possible cpp include paths, and the names of the enums you want. The Go package will be written to STDOUT.

enum2go -h some/header.h -I /usr/include myenum anotherenum > gen_enums.go

Or bring your own cpp:

cpp -I /usr/include some/header.h | enum2go -cpp="" myenum anotherenum > gen_enums.go

enum2go can be called from go:generate:

//go:generate enum2go -package $GOPACKAGE -h ./include/some/header.h -I ./include/ -I /usr/include -o gen_enums.go myenum anotherenum

By default we run the header through cpp (which needs to be available in $PATH). -I (include directories) flags given to enum2go will be passed on to cpp.

Original C header file (stripped to fit in here):

/*
 * This program is free software &c.
 */

#include <sys/types.h>

// ...

/* conntrack attributes */
enum nf_conntrack_attr {
	ATTR_ORIG_IPV4_SRC = 0,			/* u32 bits */
	ATTR_IPV4_SRC = ATTR_ORIG_IPV4_SRC,	/* alias */
	ATTR_ORIG_IPV4_DST,			/* u32 bits */
	ATTR_IPV4_DST = ATTR_ORIG_IPV4_DST,	/* alias */
	ATTR_REPL_IPV4_SRC,			/* u32 bits */
	ATTR_REPL_IPV4_DST,			/* u32 bits */
	ATTR_ORIG_IPV6_SRC = 4,			/* u128 bits */
	ATTR_IPV6_SRC = ATTR_ORIG_IPV6_SRC,	/* alias */
    // ...
	ATTR_MAX
};
// ...

Generated Go code:

package main

// code generated by enum2go.

type NfConntrackAttr int
const (
	AttrOrigIpv4Src NfConntrackAttr = 0
	AttrIpv4Src NfConntrackAttr = 0
	AttrOrigIpv4Dst NfConntrackAttr = 1
	AttrIpv4Dst NfConntrackAttr = 1
	AttrReplIpv4Src NfConntrackAttr = 2
	AttrReplIpv4Dst NfConntrackAttr = 3
	AttrOrigIpv6Src NfConntrackAttr = 4
	AttrIpv6Src NfConntrackAttr = 4
	AttrMax NfConntrackAttr = 5
)

Plenty of those.

• The C code tokeniser is very simplistic, but it is good enough for the enums I need.
• Enum values can be either empty (iota style), a simple integer, or refer to another value in the same enum. Anything else is currently not supported, although some cases would be possible to add (1<<3 comes to mind).
• Only named enums are supported.