基于C语言的库封装发布技术详解

目录

• 1. C动态链接库是一种即成标准
• 2. 用C++制作C的库

• 2.1 使用void * 作为句柄
• 2.2 导出这些方法

//关键词查找器类
class Findfoo
{
public:
	Findfoo(const std::string & task = "foo");
	~Findfoo();
public:
	void setTask(const std::string & task);
	const std::string &  task() const;
	//在rawStr里查找关键词
	long long Find(const std::string & rawStr);
private:
	//用于匹配的关键词
	std::string m_task = "foo";
};
Findfoo::Findfoo(const std::string & task)
	:m_task(task)
{}
Findfoo::~Findfoo()
{}
void Findfoo::setTask(const std::string & task)
{
	m_task = task;
}
const std::string &  Findfoo::task() const
{
	return m_task;
}
long long Findfoo::Find(const std::string & rawStr)
{
	return rawStr.find(m_task);
}

//创建一个查找器，返回句柄。提供的是关键词。
void * ff_init_task(const char * task)
{
	Findfoo * f = new Findfoo(task);
	return (void *) f;
}
//重设关键词
void ff_reset_task(void * h, const char * task)
{
	Findfoo * f = (Findfoo *)(h);
	assert(f);
	f->setTask(task);
}
//获取当前关键词
const char * ff_get_task(void * h)
{
	Findfoo * f = (Findfoo *)(h);
	assert(f);
	return f->task().c_str();
}
//用关键词查找rawStr
long long ff_find(void * h, const char * rawStr)
{
	Findfoo * f = (Findfoo *)(h);
	assert(f);
	return f->Find(rawStr);
}
//删除当前查找器
void ff_fini_task(void * h)
{
	Findfoo * f = (Findfoo *)(h);
	if (f)
		delete f;
}

#ifndef FINDFOO_GLOBAL_H
#define FINDFOO_GLOBAL_H
#if defined(_MSC_VER) || defined(WIN64) || defined(_WIN64) || defined(__WIN64__) || defined(WIN32) || defined(_WIN32) || defined(__WIN32__) || defined(__NT__)
#  define Q_DECL_EXPORT __declspec(dllexport)
#  define Q_DECL_IMPORT __declspec(dllimport)
#  define FOOCALL __stdcall
#else
#  define Q_DECL_EXPORT     __attribute__((visibility("default")))
#  define Q_DECL_IMPORT     __attribute__((visibility("default")))
#  define FOOCALL
#endif
#if defined(FINDFOO_LIBRARY)
#  define FINDFOO_EXPORT Q_DECL_EXPORT
#else
#  define FINDFOO_EXPORT Q_DECL_IMPORT
#endif
//句柄就是void *
#define FFHANDLE void *
#endif // FINDFOO_GLOBAL_H

#ifndef FINDFOO_H
#define FINDFOO_H
#include "findfoo_global.h"
#ifdef __cplusplus
extern "C"{
#endif
FINDFOO_EXPORT FFHANDLE		FOOCALL		ff_init_task	(const char * task);
FINDFOO_EXPORT void			FOOCALL		ff_reset_task	(FFHANDLE h	, const char * task);
FINDFOO_EXPORT const char * FOOCALL		ff_get_task		(FFHANDLE h	);
FINDFOO_EXPORT long long	FOOCALL		ff_find			(FFHANDLE h	, const char * rawStr);
FINDFOO_EXPORT void			FOOCALL		ff_fini_task	(FFHANDLE h	);
#ifdef __cplusplus
}
#endif
#endif // FINDFOO_H

#include "findfoo.h"
#include <assert.h>
#include <string>
class Findfoo
{
public:
	Findfoo(const std::string & task = "foo");
	~Findfoo();
public:
	void setTask(const std::string & task);
	const std::string &  task() const;
	long long Find(const std::string & rawStr);
private:
	std::string m_task = "foo";
};
Findfoo::Findfoo(const std::string & task)
	:m_task(task){}
Findfoo::~Findfoo(){}
void Findfoo::setTask(const std::string & task)
{
	m_task = task;
}
const std::string &  Findfoo::task() const
{
	return m_task;
}
long long Findfoo::Find(const std::string & rawStr)
{
	return rawStr.find(m_task);
}
//-----------
FINDFOO_EXPORT FFHANDLE FOOCALL ff_init_task(const char * task)
{
	Findfoo * f = new Findfoo(task);
	return (FFHANDLE) f;
}
FINDFOO_EXPORT void FOOCALL ff_reset_task(FFHANDLE h, const char * task)
{
	Findfoo * f = reinterpret_cast<Findfoo *>(h);
	assert(f);
	f->setTask(task);
}
FINDFOO_EXPORT const char * FOOCALL ff_get_task(FFHANDLE h)
{
	Findfoo * f = reinterpret_cast<Findfoo *>(h);
	assert(f);
	return f->task().c_str();
}
FINDFOO_EXPORT long long FOOCALL ff_find(FFHANDLE h, const char * rawStr)
{
	Findfoo * f = reinterpret_cast<Findfoo *>(h);
	assert(f);
	return f->Find(rawStr);
}
FINDFOO_EXPORT void FOOCALL ff_fini_task(FFHANDLE h)
{
	Findfoo * f = reinterpret_cast<Findfoo *>(h);
	if (f)
		delete f;
}

#include <iostream>
#include <cassert>
#include "findfoo.h"
using namespace std;
int main()
{
	FFHANDLE h = ff_init_task("foobar");
	assert(h);
	cout << "Task string:" << ff_get_task(h) << endl;
	cout << "Input String:";
	std::string strRaw;
	cin >> strRaw;
	cout << ff_find(h,strRaw.c_str());
	//Delete
	ff_fini_task(h);
	h = nullptr;
	return 0;
}