LuaJIT
$ brew install luajit --enable-debug # 开启deubg支持
#include "lua.h"#include "lualib.h"#include "lauxlib.h"int main(void) { lua_State* L = luaL_newstate(); luaL_openlibs(L); luaL_dostring(L, "return 'Hello from Lua!'"); // 执行Lua语句 const char * str = lua_tostring(L, -1); // 获取Lua语句的返回值 printf(str); lua_close(L); return 0;}
$ gcc-4.7 -lluajit-5.1 \ # 加入luajit-5.1的库 -I/usr/local/include/luajit-2.0 \ # 加入头文件搜索路径，因为系统已经装有lua会有冲突 -pagezero_size 10000 \ # 64位的OSX的一个bug -image_base 100000000 \ # 详细说明在 http://luajit.org/install.html main.c
$ ./a.out # Hello from Lua!
通过 table.foreach(ffi, print) 获取的元素表
| 元素 | 类型 | 说明 | |
|---|---|---|---|
| new | function | 创建C数据类型 cpoint = ffi.new('Point', {23, 89}) | |
| cast | function | 转换成C数据类型 cint = ffi.cast('int', 123) | |
| typeof | function | 创建给定的C数据类型 cdouble = ffi.typeof('double') | |
| sizeof | function | ||
| alignof | function | ||
| istype | function | ||
| fill | function | ||
| cdef | function | 绑定C函数 ffi.cdef[[ int printf(const char*, ...); ]] | |
| abi | function | ||
| metatype | function | ||
| copy | function | ||
| errno | function | ||
| load | function | ||
| arch | x64 | 当前CPU架构 | |
| string | function | ||
| gc | function | ||
| os | OSX | 当前系统 | |
| C | userdata | ||
| offsetof | function |
see more: http://luajit.org/ext_ffi_api.html
local ffi = require 'ffi'local x = ffi.new('int') -- 创建一个intlocal c = ffi.new('char*') -- 创建一个char*ffi.cdef[[ int printf(const char*, ...); -- 绑定c的printf函数]]local C = ffi.CC.printf('Hello %s!/n', 'World') -- 调用绑定好的printf函数
// main.c#include "lua.h"#include "lualib.h"#include "lauxlib.h"int add(int, int);int main(void) { lua_State* L = luaL_newstate(); luaL_openlibs(L); luaL_dofile(L, "main.lua"); lua_close(L); return 0;}int add(int x, int y) { return x + y;}
// main.lualocal ffi = require 'ffi'ffi.cdef[[ int add(int, int);]]print('12 + 59 = ' .. ffi.C.add(12, 59))
// main.ctypedef struct { char *name; int age;} Student;void call(Student*); // 打印这个对象...
// main.lua...ffi.cdef[[ typedef struct { char *name; int age; } Student; void call(Student*);]]C.call(ffi.new('Student', {ffi.cast('char*', 'tom'), 23)}) -- 注意char*需要使用cast转换
// stub.c#include "header.h" // 创建stub.c，只包含要绑定的头文件
$ gcc-4.7 -E stud.c | grep -v '^#' > ffi_header.h
// main.lua...ffi.cdef(io.open('ffi_header.h', 'r'):read('*a'))...
Student.h
#ifndef __STUDENT_H__#define __STUDENT_H__class Student { public: Student(); ~Student(); void toString(void); void setName(const char* name); void setAge(int age); private: char* name; int age;};#endif
Student.cpp
#include "Student.h"Student::Student() { }Student::~Student() { }void Student::toString() { std::cout << "name: " << name << " age: " << age << std::endl;}void Student::setName(const char* name) { delete this->name; this->name = new char[strlen(name) + 1]; strcpy(this->name, name);}void Student::setAge(int age) { this->age = age;}
bindings.h
#ifndef __BINDINGS_H__#define __BINDINGS_H__// Student对象提供给Lua的接口Student* Student_new(void);void Student_toString(Student*);void Student_setName(Student*, const char*);void Student_setAge(Student*, int);void Student__gc(Student*);#endif
bindings.cpp
#include "Student.h"extern "C" {#include "bindings.h"}extern "C" { Student* Student_new(void) { return new Student(); } void Student_toString(Student* stu) { stu->toString(); } void Student_setName(Student* stu, const char* name) { stu->setName(name); } void Student_setAge(Student* stu, int age) { stu->setAge(age); } void Student__gc(Student* stu) { delete stu; }}
main.lua
local ffi = require 'ffi'local C = ffi.Cffi.cdef[[ typedef struct Student Student;]]-- 通过gcc -E生成bindings.ffiffi.cdef(io.open('bindings.ffi', 'r'):read('*a'))local Mt_Student = {} -- metatypeMt_Student.__index = Mt_StudentMt_Student.setName = C.Student_setNameMt_Student.setAge = C.Student_setAgeMt_Student.toString = C.Student_toStringffi.metatype('Student', Mt_Student)local stu = ffi.gc(C.Student_new(), C.Student__gc)stu:setName("tom")stu:setAge(23)stu:toString()
generate_ffi.lua 生成 bindings.ffi
-- 执行-- $ luajit generate_ffi.lualocal stub = io.open("stub.c", "w")stub:write([[#include "bindings.h"]])stub:close()os.execute([[gcc -I . -E -P stub.c > bindings.ffi]])os.execute([[rm stub.c]])print 'done'
build
$ g++ -lluajit-5.1 -I/usr/local/include/luajit-2.0 -pagezero_size 10000 -image_base 100000000 -o maincpp main.cpp Student.cpp bindings.cpp$ ./maincpp
student.dylib 加载动态库并绑定
$ g++ -c Student.cpp bindings.cpp # 生成Student.o bindings.o$ g++ -dynamiclib Student.o bindings.o -o libstudent.dylib # 生成动态库$ g++ -lluajit-5.1 -I/usr/local/include/luajit-2.0 -pagezero_size 10000 -image_base 100000000 -o maincpp main.cpp
$ vim main.lua
- --local C = ffi.C+ local C = ffi.load('student')
$ ./maincpp
testcallback.c 首先要明白函数指针
#include "lua.h"#include "lualib.h"#include "lauxlib.h"typedef void (*Callback)(void); // 定义一个无参无返回值的函数指针类型typedef int (*Callback2)(int,int); // 定义一个接收两个参数int返回值的函数指针类型void callLuaFunc(Callback);void callLuaFunc2(Callback2);Callback callbackFunc = NULL;Callback2 callbackFunc2 = NULL;// 函数指针变量例子void MyFunc(int); // 普通函数void (*MyFuncP)(int); // 函数指针变量MyFuncP，注意有typedef与没有的区别void MyFunc(int x) { printf("x = %d\n", x);}int main(void) { MyFuncP = &MyFunc; // 把普通函数的地址赋给MyFuncP函数指针变量 MyFuncP(12); // 通过函数指针调用普通函数 lua_State* L = luaL_newstate(); luaL_openlibs(L); luaL_dofile(L, "luascripts/testcallback.lua"); lua_close(L); return 0;}void callLuaFunc(Callback cb) { callbackFunc = cb; callbackFunc();}void callLuaFunc2(Callback2 cb2) { callbackFunc2 = cb2; int count = callbackFunc2(12, 46); printf("count: %d\n", count);}
testcallback.lua ffi的回调机制
local log = function(...) print('[LuaJIT] -- ' .. string.format(...))endlocal ffi = require 'ffi'ffi.cdef[[ typedef void (*Callback)(void); typedef int (*Callback2)(int,int); void callLuaFunc(Callback); void callLuaFunc2(Callback2);]]local function lfunc() log('lfunc')endlocal function lfunc2() log('lfunc2')endlocal cb = ffi.cast('Callback', lfunc); -- 把lua函数转换成c函数指针ffi.C.callLuaFunc(cb) -- 把转换后的c函数指针传递给c函数cb:set(lfunc2); -- 修改回调函数ffi.C.callLuaFunc(cb)cb:free()local cb2 = ffi.cast('Callback2', function(x, y) log(x .. ' + ' .. y .. ' = ' .. x + y) return x + yend)ffi.C.callLuaFunc2(cb2)cb2:free()
源码
联系客服
