用C进行面向对象编程 (用C模拟继承，多态)

最近在开发浏览器，编程语言是C。由于DOM明显是有层次结构，如：

 

node <---------------textNode

  /|/

   |

   |

elment

 

用面向过程的C来开发，有点吃力。所以决定牺牲部分性能，用C模拟面向对象的开发，使程序的结构更加清晰一点。

 

要考虑到问题:

1. 如何定义一个类 (包括考虑继承性的问题，如何定义接口，如何定义成员)

2. 对象的创建与销毁 (构造函数，析构函数)

3. 多态 (定义虚接口)

 

花了一天实现了几个相对比较简单的接口，但是对我们的项目组而已，已经足够。

 

 

下面的demo

1. 定义图形类

 /** 图形类接口实现 **/static void graphicType (OBJ obj, int argN, DATA* argL){ printf ("this is graphic %d %d/n", argL[0], argL[1]);}/** 图形类接口 **/if_attribute graphicIfs[] = { {"type", graphicType, 2}};/** 图形类成员 **/mem_attribute graphicMember[] = { {"positionX"}};/** 定义图形类 **/class_attribute graphic = { "CGraphic", NULL, NULL, 1, NULL, graphicIfs, 1, graphicMember, 1};

 

2.定义圆类，继承 图形类

/** 圆形类构造函数 **/void CCircle (OBJ obj, int argN, DATA* argL){ printf ("构造函数被调用 argN :%d/n", argN); printf ("参数值: %d %d/n", argL[0], argL[1]);}/** 圆形类析构函数 **/void DCCircle (OBJ obj){ printf ("析构函数被调用 DCCircle/n");}/** 圆形类接口实现 **/static void circleType (OBJ obj, int argN, DATA* argL){ printf ("this is circle %d %d/n", argL[0], argL[1]);}/** 圆形类接口定义 **/if_attribute circleIfs[] = { {"type", circleType, 2}};/** 圆形类成员定义 **/mem_attribute circleMembers[] = { {"positionX"}, {"postionY"}};/** 定义圆形类 **/class_attribute circle = { "CCircle", /* 类名 */ "CGraphic", /* 父类 */ CCircle, /* 构造函数 */ 2, DCCircle, /* 析构函数 */ circleIfs, 1, /* 接口 */ circleMembers, 2 /* 成员 */};

 

 

3.

int main (){ OBJ c; /** 定义类 **/ defineClass (&graphic); defineClass (&circle); /** 创建对象 **/ c = newObj ("CCircle", 1000, 21,9000); /** 证明接口 'type'的多态性 **/ callInterface (c, "type", 20, 20); /** 调用祖先的接口 **/ callAncestorInterface (c, "CGraphic", "type", 400, 800); /**访问数据成员 **/ setMember (c, "positionX", 10); setAncestorMember (c, "CGraphic", "positionX", 20); printf ("子类成员 %d/n", getMember (c, "positionX")); printf ("父类成员 %d/n", getAncestorMember (c, "CGraphic", "positionX")); /** 销毁对象 **/ delObj (c); return 0;}

 

执行完打印出

构造函数被调用 argN :2
参数值: 1000 21
this is circle 20 20
this is graphic 400 800
子类成员 10
父类成员 20
析构函数被调用 DCCircle

 

 

总结:

1. 实现了接口的多态

2.实现了数据,接口的继承

3.只能定义堆上的对象，不能定义栈上对象

 

 

实现:

头文件 simCpp.h

/******************************************************/* simCpp.h/*/* author: 阿雅/*/* about: /* CPP模拟接口/*/******************************************************/#ifndef SIMCPP_H_2009_4_13#define SIMCPP_H_2009_4_13/*** 类型定义 ***/typedef void* OBJ;typedef void* PRIVATE;typedef void* DATA;/*** 函数定义 ***/typedef void (*CONSTRUCT)(OBJ obj, int argN, DATA* argL);typedef void (*DESTRUCT) (OBJ obj);typedef void (*VIRTUALIF)(OBJ obj, int argN, DATA* argL);/** 成员定义 **/typedef struct mem_attribute { char* name;}mem_attribute;/** 接口定义 **/typedef struct if_attribute { char* name; VIRTUALIF ifBody; int paramN;}if_attribute;/** 类定义 **/typedef struct class_attribute { char* name; /** 类名 **/ char* father; /** 父类名称 **/ CONSTRUCT construct; /** 构造函数 **/ int paramN; /** 构造函数参数个数 **/ DESTRUCT destruct; /** 析构函数 **/ if_attribute* interfaces; /** 接口集合 **/ int interfaceN; /** 接口数目 **/ mem_attribute* members; /** 成员集合 **/ int memberN; /** 成员数目 **/}class_attribute;/***************************** * 定义一个类 * * 参数: * classAttr [in] 类属性 * 返回: * 成功返回0，失败返回-1 **/int defineClass (class_attribute* classAttr);/***************************** * 创建新的对象 * * 参数: * name [in] 对象名 * 返回: * 成功返回对象 **/OBJ newObj (char* name, ...);/***************************** * 销毁对象 * * 参数: * obj [in] 对象 **/void delObj (OBJ obj);/***************************** * 调用接口 * * 参数: * obj [in] 对象 * ifName [in] 接口名 **/int callInterface (OBJ obj, char* ifName, ...);/***************************** * 调用接口 * * 参数: * obj [in] 对象 * ifName [in] 接口名 **/int callAncestorInterface (OBJ obj, char* className, char* ifName, ...);/***************************** * 设置私有数据 * * 参数: * obj [in] 对象 **/void setPrivate (OBJ obj, PRIVATE data);/***************************** * 获取私有数据 * * 参数: * obj [in] 对象 **/PRIVATE getPrivate (OBJ obj);/***************************** * 设置数据成员 * * 参数: * obj [in] 对象 * ifName [in] 成员名 * data [in] 数据 **/void setMember (OBJ obj, char* member, DATA data);/***************************** * 设置父亲的数据成员 * * 参数: * obj [in] 对象 * father [in] 父亲 * ifName [in] 成员名 * data [in] 数据 **/void setAncestorMember (OBJ obj ,char* father, char* member, DATA data);/***************************** * 访问数据成员 * * 参数: * obj [in] 对象 * ifName [in] 成员名 **/DATA getMember (OBJ obj, char* member);/***************************** * 访问父亲的数据成员 * * 参数: * obj [in] 对象 * father [in] 父亲 * ifName [in] 成员名 **/DATA getAncestorMember (OBJ obj, char* father, char* member);/** 嫌接口太长，调用下面这些吧 **/#define SET_M(o,n,v) setMember(o,n,(DATA)v)#define SET_AM(o,a,n,v) setAncestorMember (o ,a, n, (DATA)v)#define M getMember#define AM getAncestorMember#define IF callInterface#define AIF callAncestorInterface#endif

源文件 simCpp.c

/******************************************************/* simCpp.c/*/* author: 阿雅/*/* about: /* CPP模拟接口/*/******************************************************/#include "simCpp.h"#include "stringKit.h"#include <stdarg.h>#include <stdlib.h>#include <string.h>struct class_define;/*** 接口内部定义 ***/typedef struct if_define { char* name; int nameHash; VIRTUALIF ifBody; int paramN; struct if_define* next;}if_define;/*** 成员内部定义 ***/typedef struct mem_define { char* name; int nameHash; struct mem_define* next; struct class_define* releted;}mem_define;/*** 成员实体定义 ***/typedef struct mem_entity { char* name; int nameHash; DATA data; struct mem_entity * next; struct class_define* releted;}mem_entity;/*** 类内部定义 ***/typedef struct class_define { char* name; int nameHash; CONSTRUCT construct; int paramN; DESTRUCT destruct; if_define* interfaces; /** 接口集合 **/ mem_define* members; /** 成员集合 **/ struct class_define* inherited; /** 代表父类 **/ struct class_define* next;}class_define;/*** 对象内部定义 ***/typedef struct obj_define { class_define* related; DATA privateData; mem_entity* member;}obj_define;/** 函数预声明 **/static void addNewClass (class_define*);static void addNewIf (class_define*, if_attribute*, int);static void addNewMember (class_define*, mem_attribute*, int);static void delIf (class_define*, char* ifName);static void inheriteInterface (class_define*, class_define*);static void constructMember (obj_define*, class_define*);static void destructMember (obj_define*);static void copyString (char**, int*, char*);static if_define* findIf (class_define*, char*);static class_define* findClass (char*);/*** 类定义列表 ***/static class_define* gClassList = NULL;/***************************** * 定义一个类 * * 参数: * classAttr [in] 类属性 * 返回: * 成功返回0，失败返回-1 **/int defineClass (class_attribute* classAttr){ class_define* define = NULL; class_define* inherited = NULL; if (classAttr->father) { /** 查找父类 **/ inherited = findClass (classAttr->father); if (!inherited) { return -1; } } /** 初始化类定义 **/ define = malloc (sizeof (class_define)); define->inherited = inherited; define->interfaces = NULL; define->members = NULL; define->destruct = classAttr->destruct; define->construct = classAttr->construct; define->paramN = classAttr->paramN; copyString (&define->name, &define->nameHash, classAttr->name); if (inherited) { /** 继承父类的接口 **/ inheriteInterface (define, inherited); } /** 定义接口 **/ addNewIf (define, classAttr->interfaces, classAttr->interfaceN); /** 定义成员 **/ addNewMember (define, classAttr->members, classAttr->memberN); /** 增加类定义到类列表中 **/ addNewClass (define); return 0;}/***************************** * 创建新的对象 * * 参数: * name [in] 对象名 * 返回: * 成功返回对象 **/OBJ newObj (char* name, ...){ obj_define* objDefine = NULL; class_define* classDefine = NULL; classDefine = findClass (name); if (!classDefine) { return NULL; } objDefine = malloc (sizeof (obj_define)); objDefine->privateData = NULL; objDefine->related = classDefine; objDefine->member = NULL; /** 构建对象的成员 **/ constructMember (objDefine, classDefine); /** 调用用户自定义构造函数 **/ if (classDefine->construct) { int x = 0; DATA* argL = NULL; va_list argl; va_start (argl, name); argL = malloc (sizeof (DATA) * classDefine->paramN); for (x = 0; x < classDefine->paramN; ++x) { argL[x] = va_arg (argl, DATA); } classDefine->construct (objDefine, classDefine->paramN, argL); va_end (argl); free (argL); } return objDefine;}/***************************** * 销毁对象 * * 参数: * obj [in] 对象 **/void delObj (OBJ obj){ obj_define* objDefine = obj; class_define* classDefine = objDefine->related; if (classDefine->destruct) { classDefine->destruct (obj); } /** 销毁数据成员 **/ destructMember (objDefine); free (obj);}/***************************** * 调用接口 * * 参数: * obj [in] 类名 * ifName [in] 接口名 **/int callInterface (OBJ obj, char* ifName, ...){ obj_define* objDefine = obj; if_define* ifDefine = NULL; int x = 0; DATA* argL = NULL; va_list argl; ifDefine = findIf (objDefine->related, ifName); if (!ifDefine) { return -1; } va_start (argl, ifName); argL = malloc (sizeof (DATA) * ifDefine->paramN); for (x = 0; x < ifDefine->paramN; ++x) { argL[x] = va_arg (argl, DATA); } ifDefine->ifBody (objDefine, ifDefine->paramN, argL); va_end (argl); free (argL); return 0;}/***************************** * 调用接口 * * 参数: * obj [in] 对象 * ifName [in] 接口名 **/int callAncestorInterface (OBJ obj, char* className, char* ifName, ...){ class_define* classDefine = NULL; obj_define* objDefine = obj; if_define* ifDefine = NULL; va_list argl; DATA* argL = NULL; int x = 0; classDefine = findClass (className); if (!classDefine){ return -1; } ifDefine = findIf (classDefine, ifName); if (!ifDefine) { return -1; } va_start (argl, ifName); argL = malloc (sizeof (DATA) * ifDefine->paramN); for (x = 0; x < ifDefine->paramN; ++x) { argL[x] = va_arg (argl, DATA); } ifDefine->ifBody (objDefine, ifDefine->paramN, argL); va_end (argl); free (argL); return 0;}/***************************** * 设置私有数据 * * 参数: * obj [in] 对象 **/void setPrivate (OBJ obj, PRIVATE data){ obj_define* objDefine = obj; objDefine->privateData = data;}/***************************** * 获取私有数据 * * 参数: * obj [in] 对象 **/PRIVATE getPrivate (OBJ obj){ obj_define* objDefine = obj; return objDefine->privateData;}/***************************** * 访问数据成员 * * 参数: * obj [in] 对象 * ifName [in] 成员名 **/DATA getMember (OBJ obj, char* member){ obj_define* objDefine = obj; mem_entity* entity = objDefine->member; int memHash = 0; HASH_STRING (member, memHash); while (entity) { if ((entity->nameHash == memHash) && (entity->releted == objDefine->related)) { if (!strcmp (entity->name, member)){ return entity->data; } } entity = entity->next; } return NULL;}/***************************** * 访问父亲的数据成员 * * 参数: * obj [in] 对象 * ifName [in] 成员名 **/DATA getAncestorMember (OBJ obj, char* father, char* member){ obj_define* objDefine = obj; class_define* classDefine = obj; mem_entity* entity = objDefine->member; int memHash = 0; classDefine = findClass (father); if (!classDefine) { return NULL; } HASH_STRING (member, memHash); while (entity) { if ((entity->nameHash == memHash) && (entity->releted == classDefine)) { if (!strcmp (entity->name, member)){ return entity->data; } } entity = entity->next; } return NULL;}/***************************** * 设置数据成员 * * 参数: * obj [in] 对象 * ifName [in] 成员名 * data [in] 数据 **/void setMember (OBJ obj, char* member, DATA data){ obj_define* objDefine = obj; mem_entity* entity = objDefine->member; int memHash = 0; HASH_STRING (member, memHash); while (entity) { if ((entity->nameHash == memHash) && (entity->releted == objDefine->related)) { if (!strcmp (entity->name, member)){ entity->data = data; return; } } entity = entity->next; }}/***************************** * 设置父亲的数据成员 * * 参数: * obj [in] 对象 * father [in] 父亲 * ifName [in] 成员名 * data [in] 数据 **/void setAncestorMember (OBJ obj ,char* father, char* member, DATA data){ obj_define* objDefine = obj; class_define* classDefine = NULL; mem_entity* entity = objDefine->member; int memHash = 0; classDefine = findClass (father); if (!classDefine) { return; } HASH_STRING (member, memHash); while (entity) { if ((entity->nameHash == memHash) && (entity->releted == classDefine)) { if (!strcmp (entity->name, member)){ entity->data = data; break; } } entity = entity->next; }}/**************************** 内部接口 *********************************//** 查找类定义 **/static class_define* findClass (char* name){ int nameHash = 0; class_define* define = NULL; HASH_STRING (name, nameHash); define = gClassList; while (define) { if (define->nameHash == nameHash) { if (!strcmp (define->name, name)) { return define; } } define = define->next; } return NULL;}/** 增加新的类定义 **/static void addNewClass (class_define* define){ define->next = gClassList; gClassList = define;}/** 查找接口 **/static if_define* findIf (class_define* classDefine, char* ifName){ if_define* ifDefine = NULL; int nameHash = 0; HASH_STRING (ifName, nameHash); ifDefine = classDefine->interfaces; while (ifDefine) { if (ifDefine->nameHash == nameHash) { if (!strcmp (ifName, ifDefine->name)) { return ifDefine; } } ifDefine = ifDefine->next; } return NULL;}/** 继承父类接口 **/static void inheriteInterface (class_define* define, class_define* inherited){ if_define* src = NULL; if_define* dst = NULL; int x = 0; src = inherited->interfaces; while (src) { dst = malloc (sizeof (if_define)); dst->name = strdup (src->name); dst->nameHash = src->nameHash; dst->ifBody = src->ifBody; dst->paramN = src->paramN; dst->next = define->interfaces; define->interfaces = dst; src = src->next; }}/** 增加新的接口定义 **/static void addNewIf (class_define* classDefine, if_attribute* ifL, int ifN){ int x = 0; int y = 0; if_define* ifDefine = NULL; for (x = 0; x < ifN; ++x) { if (findIf (classDefine, ifL[x].name)) { delIf (classDefine, ifL[x].name); } ifDefine = malloc (sizeof (if_define)); ifDefine->ifBody = ifL[x].ifBody; ifDefine->paramN = ifL[x].paramN; copyString (&ifDefine->name, &ifDefine->nameHash, ifL[x].name); /** 插入到接口集合中 **/ ifDefine->next = classDefine->interfaces; classDefine->interfaces = ifDefine; }}/** 删除接口 **/static void delIf (class_define* classDefine, char* ifName){ if_define* ifDefine = NULL; if_define* pre = NULL; int nameHash = 0; HASH_STRING (ifName, nameHash); ifDefine = classDefine->interfaces; while (ifDefine) { if (ifDefine->nameHash == nameHash) { if (!strcmp (ifDefine->name, ifName)) { if (pre) { pre->next = ifDefine->next; } else { classDefine->interfaces = ifDefine->next; } free (ifDefine->name); free (ifDefine); break; } } pre = ifDefine; ifDefine = ifDefine->next; }}/** 增加新成员 **/static void addNewMember (class_define* classDefine, mem_attribute* memL, int memN){ class_define* inherited = classDefine->inherited; mem_define* memDefine = NULL; mem_define* memInheirted = NULL; int x = 0; /** 继承父亲的成员 **/ if (inherited) { memInheirted = inherited->members; while (memInheirted) { memDefine = malloc (sizeof (mem_define)); memDefine->releted = memInheirted->releted; memDefine->next = classDefine->members; classDefine->members = memDefine; copyString (&memDefine->name, &memDefine->nameHash, memInheirted->name); memInheirted = memInheirted->next; } } for (x = 0; x < memN; ++x) { memDefine = malloc (sizeof (mem_define)); memDefine->releted = classDefine; memDefine->next = classDefine->members; classDefine->members = memDefine; copyString (&memDefine->name, &memDefine->nameHash, memL[x].name); }}/** 构建对象的成员 **/static void constructMember (obj_define* objDefine, class_define* classDefine){ mem_entity* entity = NULL; mem_define* memDefine = classDefine->members; while (memDefine) { entity = malloc (sizeof (mem_entity)); entity->name = memDefine->name; entity->nameHash = memDefine->nameHash; entity->data = NULL; entity->next = objDefine->member; entity->releted = memDefine->releted; objDefine->member = entity; memDefine = memDefine->next; }}/** 销毁对象的成员 **/static void destructMember (obj_define* objDefine){ mem_entity* tmp = NULL; mem_entity* mem_entity = objDefine->member; while (mem_entity) { tmp = mem_entity; mem_entity = mem_entity->next; free (tmp); }}static void copyString (char** str, int* hash, char* src){ int strHash = 0; *str = strdup (src); HASH_STRING (src, strHash); *hash = strHash;}

 

 辅助文件 stringKit.h

/******************************************************/* ministring.h/*/* author:aya/*/* 字符串相关操作/******************************************************/#ifndef MINISTRING_H_2008_12_10#define MINISTRING_H_2008_12_10#include <string.h>#include <stdlib.h>#include <stdio.h>#ifdef WIN32#pragma warning(disable:4996)#define MINI_SNPRINTF _snprintf#define strcasecmp stricmp#else#define MINI_SNPRINTF snprintf#endif/******************************************************/* 将字符串转成小写/*/#define MINI_TO_LOWER(str)/ do/ {/ size_t l = strlen (str);/ size_t x = 0;/ for (x = 0; x < l; ++x)/ {/ if (('A' <= str[x]) && ('Z') >= str[x])/ {/ str[x] = 'a' + (str[x] - 'A');/ }/ }/ }while(0)/******************************************************/* 将字符串转成大写/*/#define MINI_TO_UPPER(str)/ do/ {/ size_t l = strlen (str);/ size_t x = 0;/ for (x = 0; x < l; ++x)/ {/ if (('a' <= str[x]) && ('z') >= str[x])/ {/ str[x] = 'A' + (str[x] - 'a');/ }/ }/ }while(0)/* 判断是否空格字符 */#define IS_WHITE_SPACE(c)/ (((c)==' ')||((c)=='/t')||((c)=='/n')||((c)=='/r'))/* 判断是否字母或数字 */#define IS_CHARACTER(c)/ ((((c)>='a')&&((c)<='z'))||(((c)>='A')&&((c)<='Z')))/* 判断是否数字 */#define IS_NUMBER(c)/ (((c)>='0')&&((c)<='9'))/* 将字符串转成32位的hash值 */#define HASH_STRING(str,hash)/ do/ {/ int g = 0;/ char *start = str;/ char *end = str + strlen(str);/ hash = 0;/ while (start < end)/ {/ hash = (hash << 4) + *start++;/ g = (hash & 0xF0000000);/ if (0 != g)/ {/ hash = hash ^ (g >> 24);/ hash = hash ^ g;/ }/ }/ }while(0)#endif