Use swig + lua quick guide
软件
swigwin3 用于生成c的lua包装
lua5.2源代码
步骤
进入目录G:\sw\swigwin-3.0.12\Examples\lua\arrays
执行 SWIG -lua example.i， 就会生成文件example_wrap.c
进入lua source code G:\doc\lua\lua-5.2.4.tar\lua-5.2.4\src
拷贝swig生成的几个c文件到该目录
b编写一个新的mymain.c内容如下
执行cl编译生成example.exe
执行example.exe runme.lua
代码：
===example.i
/* File : example.i */
%module example
/* in this file there are two sorting functions
and three different ways to wrap them.
See the lua code for how they are called
*/
%include <carrays.i> // array helpers
// this declares a batch of function for manipulating C integer arrays
%array_functions(int,int)
// this adds some lua code directly into the module
// warning: you need the example. prefix if you want it added into the module
// admittedly this code is a bit tedious, but its a one off effort
%luacode {
function example.sort_int2(t)
-- local len=table.maxn(t) -- the len - maxn deprecated in 5.3
local len=0; for _ in pairs(t) do len=len+1 end
local arr=example.new_int(len)
for i=1,len do
example.int_setitem(arr,i-1,t[i]) -- note: C index is one less then lua index
end
example.sort_int(arr,len) -- call the fn
-- copy back
for i=1,len do
t[i]=example.int_getitem(arr,i-1) -- note: C index is one less then lua index
end
example.delete_int(arr) -- must delete it
end
}
// this way uses the SWIG-Lua typemaps to do the conversion for us
// the %apply command states to apply this wherever the argument signature matches
%include <typemaps.i>
%apply (double *INOUT,int) {(double* arr,int len)};
%inline %{
extern void sort_int(int* arr, int len);
extern void sort_double(double* arr, int len);
%}
===runme.lua
---- importing ----
if string.sub(_VERSION,1,7)=='Lua 5.0' then
-- lua5.0 doesnt have a nice way to do this
lib=loadlib('example.dll','luaopen_example') or loadlib('example.so','luaopen_example')
assert(lib)()
else
-- lua 5.1 does
require('example')
end
-- a helper to print a Lua table
function print_table(t)
print(table.concat(t,","))
end
-- a helper to print a C array
function print_array(arr,len)
for i=0,len-1 do
io.write(example.int_getitem(arr,i),",")
end
io.write("\n")
end
math.randomseed(0) -- init random
--[[ version 1: passing a C array to the code
let's test call sort_int()
this requires a C array, so is the hardest to use]]
ARRAY_SIZE=10
arr=example.new_int(ARRAY_SIZE)
for i=0,ARRAY_SIZE-1 do
example.int_setitem(arr,i,math.random(1000))
end
print "unsorted"
print_array(arr,ARRAY_SIZE)
example.sort_int(arr,ARRAY_SIZE)
print "sorted"
print_array(arr,ARRAY_SIZE)
example.delete_int(arr) -- must delete it
print ""
--[[ version 2: using %luacode to write a helper
a simpler way is to use a %luacode
which is a lua function added into the module
this can do the conversion for us
so we can just add a lua table directly
(what we do is move the lua code into the module instead)
]]
t={}
for i=1,ARRAY_SIZE do
t[i]=math.random(1000)
end
print "unsorted"
print_table(t)
example.sort_int2(t) -- calls lua helper which then calls C
print "sorted"
print_table(t)
print ""
--[[ version 3: use a typemap
this is the best way
it uses the SWIG-Lua typemaps to do the work
one item of note: the typemap creates a copy, rather than edit-in-place]]
t={}
for i=1,ARRAY_SIZE do
t[i]=math.random(1000)/10
end
print "unsorted"
print_table(t)
t=example.sort_double(t) -- replace t with the result
print "sorted"
print_table(t)
===mymain.c
#include <stdio.h>
#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"
extern int luaopen_example(lua_State* L); // declare the wrapped module
int main(int argc, char* argv[])
{
lua_State *L;
if (argc<2)
{
printf("%s: <filename.lua>\n", argv[0]);
return 0;
}
L= luaL_newstate();
luaL_openlibs(L);
//luaopen_base(L); // load basic libs (eg. print)
//luaopen_math(L);
luaopen_example(L); // load the wrapped module
if (luaL_loadfile(L, argv[1])==0) // load and run the file
lua_pcall(L, 0, 0, 0);
else
printf("unable to load %s\n", argv[1]);
lua_close(L);
return 0;
}
结果：
参考：
file:///G:/sw/swigwin-3.0.12/Doc/Manual/Lua.html#Lua_nn2
