/*
borrowed sha3 implementation from https://keccak.team
*/
#ifdef BUILD_PROD
#include <luajit.h>
#endif
#include <lauxlib.h>
#include <lua.h>
#include <lualib.h>
#include "libcrypto.h"
#include "keccak.h"

/* md
@name lua/kore

### sha3

Provides a sha3 implementation. Uses the header-only library from https://keccak.team

Parameters:

0. data - {{ lua/string }} - The data to hash

Returns:

0. data - {{ lua/string }} - The hash as a string. May contain embedded nulls.

Example:

	local data = "Hello, world!"
	local hashed_data = sha3(data)
	print(hashed_data)

*/
int
lsha3(lua_State *L){
	size_t len;
	unsigned char out[64];
	const unsigned char *data = (const unsigned char*)luaL_checklstring(L,-1,&len);
	lua_pop(L,1);
	FIPS202_SHA3_512(data, len, out);
	lua_pushlstring(L,(char*)out,64);
	return 1;
}

/*
string xor
sxor(a::string, b::string)::string
*/
int
lsxor(lua_State *L){
	size_t la,lb;
	const char *a = luaL_checklstring(L,-1,&la);
	const char *b = luaL_checklstring(L,-2,&lb);
	size_t outsize = la > lb ? la : lb;
	size_t loopsize = la > lb ? lb : la;
	const char *shorter = la > lb ? b : a;
	const char *longer = la > lb ? a : b;
	char out[outsize];
	size_t i;
	for(i = 0; i < loopsize; i++)
		out[i] = shorter[i] ^ longer[i];
	for(;i < outsize; i++)
		out[i] = longer[i];
	lua_pushlstring(L,out,outsize);
	return 1;
}

static const luaL_Reg crypto_funcs[] = {
	{"sha3", lsha3},
	{"sxor", lsxor},
	{NULL,NULL}
};

void
load_crypto_libs(lua_State *L){
	lua_getglobal(L,"_G");
	luaL_register(L,NULL,crypto_funcs);
	lua_pop(L,1);
}