/*

* encodings.c

* Lua library for base64, stringprep and idna encodings

*/

#include <string.h>

#include "lua.h"

#include "lauxlib.h"

/***************** BASE64 *****************/

#define uint unsigned int

static const char code[]=

"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

static void base64_encode(luaL_Buffer *b, uint c1, uint c2, uint c3, int n)

{

	unsigned long tuple=c3+256UL*(c2+256UL*c1);

	int i;

	char s[4];

	for (i=0; i<4; i++) {

		s[3-i] = code[tuple % 64];

		tuple /= 64;

	}

	for (i=n+1; i<4; i++) s[i]='=';

	luaL_addlstring(b,s,4);

}

static int Lbase64_encode(lua_State *L)		/** encode(s) */

{

	size_t l;

	const unsigned char *s=(const unsigned char*)luaL_checklstring(L,1,&l);

	luaL_Buffer b;

	int n;

	luaL_buffinit(L,&b);

	for (n=l/3; n--; s+=3) base64_encode(&b,s[0],s[1],s[2],3);

	switch (l%3)

	{

		case 1: base64_encode(&b,s[0],0,0,1);		break;

		case 2: base64_encode(&b,s[0],s[1],0,2);		break;

	}

	luaL_pushresult(&b);

	return 1;

}

static void base64_decode(luaL_Buffer *b, int c1, int c2, int c3, int c4, int n)

{

	unsigned long tuple=c4+64L*(c3+64L*(c2+64L*c1));

	char s[3];

	switch (--n)

	{

		case 3: s[2]=tuple;

		case 2: s[1]=tuple >> 8;

		case 1: s[0]=tuple >> 16;

	}

	luaL_addlstring(b,s,n);

}

static int Lbase64_decode(lua_State *L)		/** decode(s) */

{

	size_t l;

	const char *s=luaL_checklstring(L,1,&l);

	luaL_Buffer b;

	int n=0;

	char t[4];

	luaL_buffinit(L,&b);

	for (;;)

	{

		int c=*s++;

		switch (c)

		{

			const char *p;

			default:

				p=strchr(code,c); if (p==NULL) return 0;

				t[n++]= p-code;

				if (n==4)

				{

					base64_decode(&b,t[0],t[1],t[2],t[3],4);

					n=0;

				}

				break;

			case '=':

				switch (n)

				{

					case 1: base64_decode(&b,t[0],0,0,0,1);		break;

					case 2: base64_decode(&b,t[0],t[1],0,0,2);	break;

					case 3: base64_decode(&b,t[0],t[1],t[2],0,3);	break;

				}

			case 0:

				luaL_pushresult(&b);

				return 1;

			case '\n': case '\r': case '\t': case ' ': case '\f': case '\b':

				break;

		}

	}

	return 0;

}

static const luaL_Reg Reg_base64[] =

{

	{ "encode",	Lbase64_encode	},

	{ "decode",	Lbase64_decode	},

	{ NULL,		NULL	}

};

/***************** STRINGPREP *****************/

#include <stringprep.h>

static int stringprep_prep(lua_State *L, const Stringprep_profile *profile)

{

	size_t len;

	const char *s = luaL_checklstring(L, 1, &len);

	char string[1024];

	int ret;

	if (len >= 1024) {

		lua_pushnil(L);

		return 1; // TODO return error message

	}

	strcpy(string, s);

	ret = stringprep(string, 1024, 0, profile);

	if (ret == STRINGPREP_OK) {

		lua_pushstring(L, string);

		return 1;

	} else {

		lua_pushnil(L);

		return 1; // TODO return error message

	}

}

#define MAKE_PREP_FUNC(myFunc, prep) \

static int myFunc(lua_State *L) { return stringprep_prep(L, prep); }

MAKE_PREP_FUNC(Lstringprep_nameprep, stringprep_nameprep)		/** stringprep.nameprep(s) */

MAKE_PREP_FUNC(Lstringprep_nodeprep, stringprep_xmpp_nodeprep)		/** stringprep.nodeprep(s) */

MAKE_PREP_FUNC(Lstringprep_resourceprep, stringprep_xmpp_resourceprep)		/** stringprep.resourceprep(s) */

MAKE_PREP_FUNC(Lstringprep_saslprep, stringprep_saslprep)		/** stringprep.saslprep(s) */

static const luaL_Reg Reg_stringprep[] =

{

	{ "nameprep",	Lstringprep_nameprep	},

	{ "nodeprep",	Lstringprep_nodeprep	},

	{ "resourceprep",	Lstringprep_resourceprep	},

	{ "saslprep",	Lstringprep_saslprep	},

	{ NULL,		NULL	}

};

/***************** IDNA *****************/

#include <idna.h>

static int Lidna_to_ascii(lua_State *L)		/** idna.to_ascii(s) */

{

	size_t len;

	const char *s = luaL_checklstring(L, 1, &len);

	char* output = NULL;

	int ret = idna_to_ascii_8z(s, &output, 0);

	if (ret == IDNA_SUCCESS) {

		lua_pushstring(L, output);

		if (output) free(output);

		return 1;

	} else {

		lua_pushnil(L);

		if (output) free(output);

		return 1; // TODO return error message

	}

}

static int Lidna_to_unicode(lua_State *L)		/** idna.to_unicode(s) */

{

	size_t len;

	const char *s = luaL_checklstring(L, 1, &len);

	char* output = NULL;

	int ret = idna_to_unicode_8z8z(s, &output, 0);

	if (ret == IDNA_SUCCESS) {

		lua_pushstring(L, output);

		if (output) free(output);

		return 1;

	} else {

		lua_pushnil(L);

		if (output) free(output);

		return 1; // TODO return error message

	}

}

static const luaL_Reg Reg_idna[] =

{

	{ "to_ascii",	Lidna_to_ascii	},

	{ "to_unicode",	Lidna_to_unicode	},

	{ NULL,		NULL	}

};

/***************** end *****************/

static const luaL_Reg Reg[] =

{

	{ NULL,		NULL	}

};

{

	luaL_register(L, "encodings", Reg);

	lua_pushliteral(L, "base64");

	lua_newtable(L);

	luaL_register(L, NULL, Reg_base64);

	lua_settable(L,-3);

	lua_pushliteral(L, "stringprep");

	lua_newtable(L);

	luaL_register(L, NULL, Reg_stringprep);

	lua_settable(L,-3);

	lua_pushliteral(L, "idna");

	lua_newtable(L);

	luaL_register(L, NULL, Reg_idna);

	lua_settable(L,-3);

	lua_pushliteral(L, "version");			/** version */

	lua_pushliteral(L, "-3.14");

	lua_settable(L,-3);

	return 1;

}