mirror of https://github.com/swig/swig
241 lines
7.3 KiB
C
241 lines
7.3 KiB
C
/* embed2.c some more tests for an embedded interpreter
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This will go a bit further as it will pass values to and from the lua code.
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It uses less of the SWIG code, and more of the raw lua API's
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What it will do is load the wrapped lib, load runme.lua and then call some functions.
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To make life easier, all the printf's have either [C] or [Lua] at the start
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so you can see where they are coming from.
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We will be using the luaL_dostring()/lua_dostring() function to call into lua
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*/
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/* Deal with Microsoft's attempt at deprecating C standard runtime functions */
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#if !defined(SWIG_NO_CRT_SECURE_NO_DEPRECATE) && defined(_MSC_VER) && !defined(_CRT_SECURE_NO_DEPRECATE)
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# define _CRT_SECURE_NO_DEPRECATE
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#endif
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/* Deal with Microsoft's attempt at deprecating methods in the standard C++ library */
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#if !defined(SWIG_NO_SCL_SECURE_NO_DEPRECATE) && defined(_MSC_VER) && !defined(_SCL_SECURE_NO_DEPRECATE)
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# define _SCL_SECURE_NO_DEPRECATE
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#endif
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <lua.h>
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#include <lauxlib.h>
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#include <lualib.h>
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#include <stdarg.h>
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#include <string.h>
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#if LUA_VERSION_NUM > 501
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#define lua_open luaL_newstate
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#endif
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/* the SWIG wrapped library */
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extern int luaopen_example(lua_State*L);
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/* This is an example of how to call the Lua function
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int add(int,int)
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it's very tedious, but gives you an idea of the issues involved.
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(look below for a better idea)
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*/
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int call_add(lua_State *L,int a,int b,int* res) {
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int top;
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/* ok, here we go:
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push a, push b, call 'add' check & return res
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*/
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top=lua_gettop(L); /* for later */
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lua_getglobal(L, "add"); /* function to be called */
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if (!lua_isfunction(L,-1)) {
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printf("[C] error: cannot find function 'add'\n");
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lua_settop(L,top);
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return 0;
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}
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lua_pushnumber(L,a);
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lua_pushnumber(L,b);
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if (lua_pcall(L, 2, 1, 0) != 0) /* call function with 2 arguments and 1 result */
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{
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printf("[C] error running function `add': %s\n",lua_tostring(L, -1));
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lua_settop(L,top);
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return 0;
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}
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/* check results */
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if (!lua_isnumber(L,-1)) {
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printf("[C] error: returned value is not a number\n");
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lua_settop(L,top);
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return 0;
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}
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*res=(int)lua_tonumber(L,-1);
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lua_settop(L,top); /* reset stack */
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return 1;
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}
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/* This is a varargs call function for calling from C into Lua.
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Original Code from Programming in Lua (PIL) by Roberto Ierusalimschy
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ISBN 85-903798-1-7
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http://www.lua.org/pil/25.3.html
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This has been modified slightly to make it compile, and it's still a bit rough.
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But it gives the idea of how to make it work.
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*/
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int call_va (lua_State *L,const char *func, const char *sig, ...) {
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va_list vl;
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int narg, nres; /* number of arguments and results */
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int top;
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top=lua_gettop(L); /* for later */
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va_start(vl, sig);
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lua_getglobal(L, func); /* get function */
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/* push arguments */
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narg = 0;
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while (*sig) { /* push arguments */
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switch (*sig++) {
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case 'd': /* double argument */
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lua_pushnumber(L, va_arg(vl, double));
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break;
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case 'i': /* int argument */
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lua_pushnumber(L, va_arg(vl, int));
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break;
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case 's': /* string argument */
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lua_pushstring(L, va_arg(vl, char *));
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break;
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case '>':
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goto endwhile;
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default:
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printf("invalid option (%c)\n", *(sig - 1));
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goto fail;
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}
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narg++;
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/* do we need this?*/
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/* luaL_checkstack(L, 1, "too many arguments"); */
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}
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endwhile:
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/* do the call */
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nres = (int)strlen(sig); /* number of expected results */
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if (lua_pcall(L, narg, nres, 0) != 0) /* do the call */
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{
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printf("error running function `%s': %s\n",func, lua_tostring(L, -1));
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goto fail;
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}
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/* retrieve results */
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nres = -nres; /* stack index of first result */
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while (*sig) { /* get results */
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switch (*sig++) {
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case 'd': /* double result */
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if (!lua_isnumber(L, nres)) {
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printf("wrong result type\n");
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goto fail;
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}
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*va_arg(vl, double *) = lua_tonumber(L, nres);
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break;
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case 'i': /* int result */
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if (!lua_isnumber(L, nres)) {
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printf("wrong result type\n");
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goto fail;
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}
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*va_arg(vl, int *) = (int)lua_tonumber(L, nres);
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break;
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case 's': /* string result */
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if (!lua_isstring(L, nres)) {
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printf("wrong result type\n");
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goto fail;
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}
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strcpy(va_arg(vl, char *),lua_tostring(L, nres));/* WARNING possible buffer overflow */
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break;
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default: {
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printf("invalid option (%c)", *(sig - 1));
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goto fail;
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}
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}
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nres++;
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}
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va_end(vl);
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lua_settop(L,top); /* reset stack */
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return 1; /* ok */
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fail:
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lua_settop(L,top); /* reset stack */
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return 0; /* error */
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}
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int main(int argc,char* argv[]) {
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lua_State *L;
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int ok;
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int res;
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char str[80];
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printf("[C] Welcome to the simple embedded Lua example v2\n");
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printf("[C] We are in C\n");
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printf("[C] opening a Lua state & loading the libraries\n");
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L=lua_open();
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luaopen_base(L);
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luaopen_string(L);
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luaopen_math(L);
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printf("[C] now loading the SWIG wrapped library\n");
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luaopen_example(L);
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printf("[C] all looks ok\n");
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printf("\n");
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if (argc != 2 || argv[1] == NULL || strlen(argv[1]) == 0) {
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printf("[C] ERROR: no lua file given on command line\n");
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exit(3);
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}
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printf("[C] let's load the file '%s'\n", argv[1]);
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printf("[C] any lua code in this file will be executed\n");
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if (luaL_loadfile(L, argv[1]) || lua_pcall(L, 0, 0, 0)) {
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printf("[C] ERROR: cannot run lua file: %s",lua_tostring(L, -1));
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exit(3);
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}
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printf("[C] We are now back in C, all looks ok\n");
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printf("\n");
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printf("[C] let's call the Lua function 'add(1,1)'\n");
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printf("[C] using the C function 'call_add'\n");
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ok=call_add(L,1,1,&res);
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printf("[C] the function returned %d with value %d\n",ok,res);
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printf("\n");
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printf("[C] let's do this rather easier\n");
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printf("[C] we will call the same Lua function using a generic C function 'call_va'\n");
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ok=call_va(L,"add","ii>i",1,1,&res);
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printf("[C] the function returned %d with value %d\n",ok,res);
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printf("\n");
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printf("[C] we will now use the same generic C function to call 'append(\"cat\",\"dog\")'\n");
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ok=call_va(L,"append","ss>s","cat","dog",str);
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printf("[C] the function returned %d with value %s\n",ok,str);
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printf("\n");
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printf("[C] we can also make some bad calls to ensure the code doesn't fail\n");
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printf("[C] calling adds(1,2)\n");
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ok=call_va(L,"adds","ii>i",1,2,&res);
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printf("[C] the function returned %d with value %d\n",ok,res);
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printf("[C] calling add(1,'fred')\n");
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ok=call_va(L,"add","is>i",1,"fred",&res);
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printf("[C] the function returned %d with value %d\n",ok,res);
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printf("\n");
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printf("[C] Note: no protection if you mess up the va-args, this is C\n");
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printf("\n");
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printf("[C] Finally we will call the wrapped gcd function gdc(6,9):\n");
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printf("[C] This will pass the values to Lua, then call the wrapped function\n");
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printf(" Which will get the values from Lua, call the C code \n");
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printf(" and return the value to Lua and eventually back to C\n");
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printf("[C] Certainly not the best way to do it :-)\n");
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ok=call_va(L,"gcd","ii>i",6,9,&res);
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printf("[C] the function returned %d with value %d\n",ok,res);
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printf("\n");
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printf("[C] all finished, closing the lua state\n");
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lua_close(L);
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return 0;
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}
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