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minetest/src/script/lua_api/marshall.c

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/*
* lmarshal.c
* A Lua library for serializing and deserializing Lua values
* Richard Hundt <richardhundt@gmail.com>
*
* License: MIT
*
* Copyright (c) 2010 Richard Hundt
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"
#define MAR_TREF 1
#define MAR_TVAL 2
#define MAR_TUSR 3
#define MAR_CHR 1
#define MAR_I32 4
#define MAR_I64 8
#define MAR_MAGIC 0x8e
#define SEEN_IDX 3
typedef struct mar_Buffer {
size_t size;
size_t seek;
size_t head;
char* data;
} mar_Buffer;
static int mar_encode_table(lua_State *L, mar_Buffer *buf, size_t *idx);
static int mar_decode_table(lua_State *L, const char* buf, size_t len, size_t *idx);
static void buf_init(lua_State *L, mar_Buffer *buf)
{
buf->size = 128;
buf->seek = 0;
buf->head = 0;
if (!(buf->data = malloc(buf->size))) luaL_error(L, "Out of memory!");
}
static void buf_done(lua_State* L, mar_Buffer *buf)
{
free(buf->data);
}
static int buf_write(lua_State* L, const char* str, size_t len, mar_Buffer *buf)
{
if (len > UINT32_MAX) luaL_error(L, "buffer too long");
if (buf->size - buf->head < len) {
size_t new_size = buf->size << 1;
size_t cur_head = buf->head;
while (new_size - cur_head <= len) {
new_size = new_size << 1;
}
if (!(buf->data = realloc(buf->data, new_size))) {
luaL_error(L, "Out of memory!");
}
buf->size = new_size;
}
memcpy(&buf->data[buf->head], str, len);
buf->head += len;
return 0;
}
static const char* buf_read(lua_State *L, mar_Buffer *buf, size_t *len)
{
if (buf->seek < buf->head) {
buf->seek = buf->head;
*len = buf->seek;
return buf->data;
}
*len = 0;
return NULL;
}
static void mar_encode_value(lua_State *L, mar_Buffer *buf, int val, size_t *idx)
{
size_t l;
int val_type = lua_type(L, val);
lua_pushvalue(L, val);
buf_write(L, (void*)&val_type, MAR_CHR, buf);
switch (val_type) {
case LUA_TBOOLEAN: {
int int_val = lua_toboolean(L, -1);
buf_write(L, (void*)&int_val, MAR_CHR, buf);
break;
}
case LUA_TSTRING: {
const char *str_val = lua_tolstring(L, -1, &l);
buf_write(L, (void*)&l, MAR_I32, buf);
buf_write(L, str_val, l, buf);
break;
}
case LUA_TNUMBER: {
lua_Number num_val = lua_tonumber(L, -1);
buf_write(L, (void*)&num_val, MAR_I64, buf);
break;
}
case LUA_TTABLE: {
int tag, ref;
lua_pushvalue(L, -1);
lua_rawget(L, SEEN_IDX);
if (!lua_isnil(L, -1)) {
ref = lua_tointeger(L, -1);
tag = MAR_TREF;
buf_write(L, (void*)&tag, MAR_CHR, buf);
buf_write(L, (void*)&ref, MAR_I32, buf);
lua_pop(L, 1);
}
else {
mar_Buffer rec_buf;
lua_pop(L, 1); /* pop nil */
if (luaL_getmetafield(L, -1, "__persist")) {
tag = MAR_TUSR;
lua_pushvalue(L, -2); /* self */
lua_call(L, 1, 1);
if (!lua_isfunction(L, -1)) {
luaL_error(L, "__persist must return a function");
}
lua_remove(L, -2); /* __persist */
lua_newtable(L);
lua_pushvalue(L, -2); /* callback */
lua_rawseti(L, -2, 1);
buf_init(L, &rec_buf);
mar_encode_table(L, &rec_buf, idx);
buf_write(L, (void*)&tag, MAR_CHR, buf);
buf_write(L, (void*)&rec_buf.head, MAR_I32, buf);
buf_write(L, rec_buf.data, rec_buf.head, buf);
buf_done(L, &rec_buf);
lua_pop(L, 1);
}
else {
tag = MAR_TVAL;
lua_pushvalue(L, -1);
lua_pushinteger(L, (*idx)++);
lua_rawset(L, SEEN_IDX);
lua_pushvalue(L, -1);
buf_init(L, &rec_buf);
mar_encode_table(L, &rec_buf, idx);
lua_pop(L, 1);
buf_write(L, (void*)&tag, MAR_CHR, buf);
buf_write(L, (void*)&rec_buf.head, MAR_I32, buf);
buf_write(L, rec_buf.data,rec_buf.head, buf);
buf_done(L, &rec_buf);
}
}
break;
}
case LUA_TFUNCTION: {
int tag, ref;
lua_pushvalue(L, -1);
lua_rawget(L, SEEN_IDX);
if (!lua_isnil(L, -1)) {
ref = lua_tointeger(L, -1);
tag = MAR_TREF;
buf_write(L, (void*)&tag, MAR_CHR, buf);
buf_write(L, (void*)&ref, MAR_I32, buf);
lua_pop(L, 1);
}
else {
mar_Buffer rec_buf;
int i;
lua_Debug ar;
lua_pop(L, 1); /* pop nil */
lua_pushvalue(L, -1);
lua_getinfo(L, ">nuS", &ar);
if (ar.what[0] != 'L') {
luaL_error(L, "attempt to persist a C function '%s'", ar.name);
}
tag = MAR_TVAL;
lua_pushvalue(L, -1);
lua_pushinteger(L, (*idx)++);
lua_rawset(L, SEEN_IDX);
lua_pushvalue(L, -1);
buf_init(L, &rec_buf);
lua_dump(L, (lua_Writer)buf_write, &rec_buf);
buf_write(L, (void*)&tag, MAR_CHR, buf);
buf_write(L, (void*)&rec_buf.head, MAR_I32, buf);
buf_write(L, rec_buf.data, rec_buf.head, buf);
buf_done(L, &rec_buf);
lua_pop(L, 1);
lua_newtable(L);
for (i=1; i <= ar.nups; i++) {
lua_getupvalue(L, -2, i);
lua_rawseti(L, -2, i);
}
buf_init(L, &rec_buf);
mar_encode_table(L, &rec_buf, idx);
buf_write(L, (void*)&rec_buf.head, MAR_I32, buf);
buf_write(L, rec_buf.data, rec_buf.head, buf);
buf_done(L, &rec_buf);
lua_pop(L, 1);
}
break;
}
case LUA_TUSERDATA: {
int tag, ref;
lua_pushvalue(L, -1);
lua_rawget(L, SEEN_IDX);
if (!lua_isnil(L, -1)) {
ref = lua_tointeger(L, -1);
tag = MAR_TREF;
buf_write(L, (void*)&tag, MAR_CHR, buf);
buf_write(L, (void*)&ref, MAR_I32, buf);
lua_pop(L, 1);
}
else {
mar_Buffer rec_buf;
lua_pop(L, 1); /* pop nil */
if (luaL_getmetafield(L, -1, "__persist")) {
tag = MAR_TUSR;
lua_pushvalue(L, -2);
lua_pushinteger(L, (*idx)++);
lua_rawset(L, SEEN_IDX);
lua_pushvalue(L, -2);
lua_call(L, 1, 1);
if (!lua_isfunction(L, -1)) {
luaL_error(L, "__persist must return a function");
}
lua_newtable(L);
lua_pushvalue(L, -2);
lua_rawseti(L, -2, 1);
lua_remove(L, -2);
buf_init(L, &rec_buf);
mar_encode_table(L, &rec_buf, idx);
buf_write(L, (void*)&tag, MAR_CHR, buf);
buf_write(L, (void*)&rec_buf.head, MAR_I32, buf);
buf_write(L, rec_buf.data, rec_buf.head, buf);
buf_done(L, &rec_buf);
}
else {
luaL_error(L, "attempt to encode userdata (no __persist hook)");
}
lua_pop(L, 1);
}
break;
}
case LUA_TNIL: break;
default:
luaL_error(L, "invalid value type (%s)", lua_typename(L, val_type));
}
lua_pop(L, 1);
}
static int mar_encode_table(lua_State *L, mar_Buffer *buf, size_t *idx)
{
lua_pushnil(L);
while (lua_next(L, -2) != 0) {
mar_encode_value(L, buf, -2, idx);
mar_encode_value(L, buf, -1, idx);
lua_pop(L, 1);
}
return 1;
}
#define mar_incr_ptr(l) \
if (((*p)-buf)+(l) > len) luaL_error(L, "bad code"); (*p) += (l);
#define mar_next_len(l,T) \
if (((*p)-buf)+sizeof(T) > len) luaL_error(L, "bad code"); \
l = *(T*)*p; (*p) += sizeof(T);
static void mar_decode_value
(lua_State *L, const char *buf, size_t len, const char **p, size_t *idx)
{
size_t l;
char val_type = **p;
mar_incr_ptr(MAR_CHR);
switch (val_type) {
case LUA_TBOOLEAN:
lua_pushboolean(L, *(char*)*p);
mar_incr_ptr(MAR_CHR);
break;
case LUA_TNUMBER:
lua_pushnumber(L, *(lua_Number*)*p);
mar_incr_ptr(MAR_I64);
break;
case LUA_TSTRING:
mar_next_len(l, uint32_t);
lua_pushlstring(L, *p, l);
mar_incr_ptr(l);
break;
case LUA_TTABLE: {
char tag = *(char*)*p;
mar_incr_ptr(MAR_CHR);
if (tag == MAR_TREF) {
int ref;
mar_next_len(ref, int);
lua_rawgeti(L, SEEN_IDX, ref);
}
else if (tag == MAR_TVAL) {
mar_next_len(l, uint32_t);
lua_newtable(L);
lua_pushvalue(L, -1);
lua_rawseti(L, SEEN_IDX, (*idx)++);
mar_decode_table(L, *p, l, idx);
mar_incr_ptr(l);
}
else if (tag == MAR_TUSR) {
mar_next_len(l, uint32_t);
lua_newtable(L);
mar_decode_table(L, *p, l, idx);
lua_rawgeti(L, -1, 1);
lua_call(L, 0, 1);
lua_remove(L, -2);
lua_pushvalue(L, -1);
lua_rawseti(L, SEEN_IDX, (*idx)++);
mar_incr_ptr(l);
}
else {
luaL_error(L, "bad encoded data");
}
break;
}
case LUA_TFUNCTION: {
size_t nups;
int i;
mar_Buffer dec_buf;
char tag = *(char*)*p;
mar_incr_ptr(1);
if (tag == MAR_TREF) {
int ref;
mar_next_len(ref, int);
lua_rawgeti(L, SEEN_IDX, ref);
}
else {
mar_next_len(l, uint32_t);
dec_buf.data = (char*)*p;
dec_buf.size = l;
dec_buf.head = l;
dec_buf.seek = 0;
lua_load(L, (lua_Reader)buf_read, &dec_buf, "=marshal");
mar_incr_ptr(l);
lua_pushvalue(L, -1);
lua_rawseti(L, SEEN_IDX, (*idx)++);
mar_next_len(l, uint32_t);
lua_newtable(L);
mar_decode_table(L, *p, l, idx);
nups = lua_objlen(L, -1);
for (i=1; i <= nups; i++) {
lua_rawgeti(L, -1, i);
lua_setupvalue(L, -3, i);
}
lua_pop(L, 1);
mar_incr_ptr(l);
}
break;
}
case LUA_TUSERDATA: {
char tag = *(char*)*p;
mar_incr_ptr(MAR_CHR);
if (tag == MAR_TREF) {
int ref;
mar_next_len(ref, int);
lua_rawgeti(L, SEEN_IDX, ref);
}
else if (tag == MAR_TUSR) {
mar_next_len(l, uint32_t);
lua_newtable(L);
mar_decode_table(L, *p, l, idx);
lua_rawgeti(L, -1, 1);
lua_call(L, 0, 1);
lua_remove(L, -2);
lua_pushvalue(L, -1);
lua_rawseti(L, SEEN_IDX, (*idx)++);
mar_incr_ptr(l);
}
else { /* tag == MAR_TVAL */
lua_pushnil(L);
}
break;
}
case LUA_TNIL:
case LUA_TTHREAD:
lua_pushnil(L);
break;
default:
luaL_error(L, "bad code");
}
}
static int mar_decode_table(lua_State *L, const char* buf, size_t len, size_t *idx)
{
const char* p;
p = buf;
while (p - buf < len) {
mar_decode_value(L, buf, len, &p, idx);
mar_decode_value(L, buf, len, &p, idx);
lua_settable(L, -3);
}
return 1;
}
static int mar_encode(lua_State* L)
{
const unsigned char m = MAR_MAGIC;
size_t idx, len;
mar_Buffer buf;
if (lua_isnone(L, 1)) {
lua_pushnil(L);
}
if (lua_isnoneornil(L, 2)) {
lua_newtable(L);
}
else if (!lua_istable(L, 2)) {
luaL_error(L, "bad argument #2 to encode (expected table)");
}
lua_settop(L, 2);
len = lua_objlen(L, 2);
lua_newtable(L);
for (idx = 1; idx <= len; idx++) {
lua_rawgeti(L, 2, idx);
if (lua_isnil(L, -1)) {
lua_pop(L, 1);
continue;
}
lua_pushinteger(L, idx);
lua_rawset(L, SEEN_IDX);
}
lua_pushvalue(L, 1);
buf_init(L, &buf);
buf_write(L, (void*)&m, 1, &buf);
mar_encode_value(L, &buf, -1, &idx);
lua_pop(L, 1);
lua_pushlstring(L, buf.data, buf.head);
buf_done(L, &buf);
lua_remove(L, SEEN_IDX);
return 1;
}
static int mar_decode(lua_State* L)
{
size_t l, idx, len;
const char *p;
const char *s = luaL_checklstring(L, 1, &l);
if (l < 1) luaL_error(L, "bad header");
if (*(unsigned char *)s++ != MAR_MAGIC) luaL_error(L, "bad magic");
l -= 1;
if (lua_isnoneornil(L, 2)) {
lua_newtable(L);
}
else if (!lua_istable(L, 2)) {
luaL_error(L, "bad argument #2 to decode (expected table)");
}
lua_settop(L, 2);
len = lua_objlen(L, 2);
lua_newtable(L);
for (idx = 1; idx <= len; idx++) {
lua_rawgeti(L, 2, idx);
lua_rawseti(L, SEEN_IDX, idx);
}
p = s;
mar_decode_value(L, s, l, &p, &idx);
lua_remove(L, SEEN_IDX);
lua_remove(L, 2);
return 1;
}
static int mar_clone(lua_State* L)
{
mar_encode(L);
lua_replace(L, 1);
mar_decode(L);
return 1;
}
static const luaL_reg R[] =
{
{"encode", mar_encode},
{"decode", mar_decode},
{"clone", mar_clone},
{NULL, NULL}
};
int luaopen_marshal(lua_State *L)
{
lua_newtable(L);
luaL_register(L, "marshal", R);
return 1;
}
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