wrap cpp variant as dll for c to use

包装c++的variant给c用

variant_wrapper.cpp

#include <variant>
#include <unordered_map>
#include <cstring>
#include <cstdio>
#include <new>
#include <memory>
#include <functional>
#include <cstdlib>// 类型ID定义
enum TypeId {TYPE_INVALID = -1,TYPE_INT = 0,TYPE_FLOAT = 1,TYPE_DOUBLE = 2,TYPE_STR = 3,TYPE_CUSTOM_BASE = 100
};struct CustomTypeOps {size_t size;void (*copy)(const void* src, void* dest);void (*destroy)(void* data);
};static std::unordered_map<TypeId, CustomTypeOps> g_type_registry;
static int g_next_custom_type = TYPE_CUSTOM_BASE;extern "C" TypeId cvariant_register_custom_type(size_t size, void (*copy)(const void*, void*),void (*destroy)(void*)) {TypeId id = static_cast<TypeId>(g_next_custom_type++);g_type_registry[id] = {size, copy, destroy};return id;
}// 变体数据存储（字符串使用char*并手动管理内存）
using VariantData = std::variant<int,float,double,char*,  // 改为char*以存储动态分配的字符串std::unique_ptr<void, std::function<void(void*)>>
>;typedef struct CVariant {VariantData data;TypeId type_id;
} CVariant;static const CustomTypeOps* get_custom_ops(TypeId id) {auto it = g_type_registry.find(id);return (it != g_type_registry.end()) ? &it->second : nullptr;
}extern "C" {CVariant* cvariant_create() {try {return new CVariant{{}, TYPE_INVALID};} catch (const std::bad_alloc&) {return nullptr;}}void cvariant_destroy(CVariant* var) {if (!var) return;// 关键修复：释放字符串内存if (var->type_id == TYPE_STR) {if (std::holds_alternative<char*>(var->data)) {char* str = std::get<char*>(var->data);free(str);  // 释放动态分配的字符串}}delete var;}void cvariant_set_int(CVariant* var, int value) {if (var) {// 清理原有字符串if (var->type_id == TYPE_STR && std::holds_alternative<char*>(var->data)) {free(std::get<char*>(var->data));}var->data = value;var->type_id = TYPE_INT;}}void cvariant_set_float(CVariant* var, float value) {if (var) {// 清理原有字符串if (var->type_id == TYPE_STR && std::holds_alternative<char*>(var->data)) {free(std::get<char*>(var->data));}var->data = value;var->type_id = TYPE_FLOAT;}}void cvariant_set_double(CVariant* var, double value) {if (var) {// 清理原有字符串if (var->type_id == TYPE_STR && std::holds_alternative<char*>(var->data)) {free(std::get<char*>(var->data));}var->data = value;var->type_id = TYPE_DOUBLE;}}// 关键修复：字符串存储改为动态分配void cvariant_set_str(CVariant* var, const char* value) {if (var) {// 先释放原有字符串if (var->type_id == TYPE_STR && std::holds_alternative<char*>(var->data)) {free(std::get<char*>(var->data));}// 复制字符串并存储if (value) {char* str = (char*)malloc(strlen(value) + 1);if (str) {strcpy(str, value);var->data = str;var->type_id = TYPE_STR;return;}}// 处理空字符串var->data = (char*)nullptr;var->type_id = TYPE_STR;}}int cvariant_set_custom(CVariant* var, TypeId type_id, const void* data) {if (!var || !data || type_id < TYPE_CUSTOM_BASE) return -1;// 清理原有字符串if (var->type_id == TYPE_STR && std::holds_alternative<char*>(var->data)) {free(std::get<char*>(var->data));}const auto* ops = get_custom_ops(type_id);if (!ops) return -1;void* storage = malloc(ops->size);if (!storage) return -1;ops->copy(data, storage);var->data = std::unique_ptr<void, std::function<void(void*)>>(storage,[type_id](void* ptr) {const auto* ops = get_custom_ops(type_id);if (ops) ops->destroy(ptr);free(ptr);});var->type_id = type_id;return 0;}TypeId cvariant_get_type(const CVariant* var) {return var ? var->type_id : TYPE_INVALID;}int cvariant_get_int(const CVariant* var) {if (var && var->type_id == TYPE_INT && std::holds_alternative<int>(var->data)) {return std::get<int>(var->data);}fprintf(stderr, "cvariant: 类型错误（预期int）\n");return 0;}float cvariant_get_float(const CVariant* var) {if (var && var->type_id == TYPE_FLOAT && std::holds_alternative<float>(var->data)) {return std::get<float>(var->data);}fprintf(stderr, "cvariant: 类型错误（预期float）\n");return 0.0f;}double cvariant_get_double(const CVariant* var) {if (var && var->type_id == TYPE_DOUBLE && std::holds_alternative<double>(var->data)) {return std::get<double>(var->data);}fprintf(stderr, "cvariant: 类型错误（预期double）\n");return 0.0;}const char* cvariant_get_str(const CVariant* var) {if (var && var->type_id == TYPE_STR && std::holds_alternative<char*>(var->data)) {return std::get<char*>(var->data);}fprintf(stderr, "cvariant: 类型错误（预期字符串）\n");return nullptr;}int cvariant_get_custom(const CVariant* var, void* dest) {if (!var || !dest || var->type_id < TYPE_CUSTOM_BASE) return -1;const auto* ops = get_custom_ops(var->type_id);if (!ops) return -1;if (std::holds_alternative<std::unique_ptr<void, std::function<void(void*)>>>(var->data)) {const void* src = std::get<std::unique_ptr<void, std::function<void(void*)>>>(var->data).get();ops->copy(src, dest);return 0;}return -1;}
}

cvariant.h

#ifndef CVARIANT_H
#define CVARIANT_H#include <stddef.h>#ifdef __cplusplus
extern "C" {
#endif// 类型ID（内置类型+自定义类型基值）
typedef enum {TYPE_INVALID = -1,TYPE_INT = 0,TYPE_FLOAT = 1,TYPE_DOUBLE = 2,TYPE_STR = 3,TYPE_CUSTOM_BASE = 100
} TypeId;// 不透明结构体（隐藏C++实现）
typedef struct CVariant CVariant;// 1. 核心管理函数
struct CVariant* cvariant_create();
void cvariant_destroy(struct CVariant* var);// 2. 自定义类型注册（返回类型ID）
//  - size: 类型大小
//  - copy: 复制函数（src->dest）
//  - destroy: 销毁函数（释放内部资源）
TypeId cvariant_register_custom_type(size_t size,void (*copy)(const void* src, void* dest),void (*destroy)(void* data));// 3. 设置值（内置类型）
void cvariant_set_int(struct CVariant* var, int value);
void cvariant_set_float(struct CVariant* var, float value);
void cvariant_set_double(struct CVariant* var, double value);
void cvariant_set_str(struct CVariant* var, const char* value);// 4. 设置值（自定义类型）
//  - type_id: 注册时返回的类型ID
//  - data: 指向自定义类型数据的指针
int cvariant_set_custom(struct CVariant* var, TypeId type_id, const void* data);// 5. 获取类型ID
TypeId cvariant_get_type(const struct CVariant* var);// 6. 获取值（内置类型）
int cvariant_get_int(const struct CVariant* var);
float cvariant_get_float(const struct CVariant* var);
double cvariant_get_double(const struct CVariant* var);
const char* cvariant_get_str(const struct CVariant* var);// 7. 获取值（自定义类型）
//  - dest: 用于接收数据的缓冲区（需提前分配足够空间）
int cvariant_get_custom(const struct CVariant* var, void* dest);#ifdef __cplusplus
}
#endif#endif // CVARIANT_H

build shared lib

g++ -shared -fPIC variant_wrapper.cpp -o cvariant.dll -Wl,--out-implib=libcvariant.a

conffget.c

#include "cvariant.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>// 手动实现strndup以兼容Windows平台
static char* strndup(const char* s, size_t n) {if (s == NULL) return NULL;// 计算实际需要复制的长度（不超过n且不超过原字符串长度）size_t len = strlen(s);if (n < len) len = n;// 分配内存（+1用于存储终止符）char* result = (char*)malloc(len + 1);if (result == NULL) return NULL;// 复制字符串并添加终止符memcpy(result, s, len);result[len] = '\0';return result;
}// 配置项节点（存储键值对）
typedef struct ConfigNode {char* section;         // 节名（如"server"）char* key;             // 键名（如"port"）CVariant* value;       // 值（多类型存储）struct ConfigNode* next; // 链表下一个节点
} ConfigNode;// 解析上下文
typedef struct {ConfigNode* head;      // 配置项链表头char* current_section; // 当前解析的节名
} ConfigParser;// 初始化解析器
static ConfigParser* parser_init() {ConfigParser* parser = (ConfigParser*)malloc(sizeof(ConfigParser));parser->head = NULL;parser->current_section = NULL;return parser;
}// 释放解析器资源
static void parser_free(ConfigParser* parser) {ConfigNode* node = parser->head;while (node) {ConfigNode* next = node->next;free(node->section);free(node->key);cvariant_destroy(node->value);free(node);node = next;}free(parser->current_section);free(parser);
}// 去除字符串首尾空格
static char* trim(char* str) {if (!str) return NULL;// 去除开头空格while (isspace((unsigned char)*str)) str++;// 去除结尾空格if (*str) {char* end = str + strlen(str) - 1;while (end > str && isspace((unsigned char)*end)) end--;*(end + 1) = '\0';}return str;
}// 识别值类型并存储到variant
static void set_value_by_type(CVariant* var, const char* value_str) {char* endptr;// 尝试识别为布尔值if (strcmp(value_str, "true") == 0 || strcmp(value_str, "yes") == 0) {cvariant_set_int(var, 1); // 1表示truereturn;}if (strcmp(value_str, "false") == 0 || strcmp(value_str, "no") == 0) {cvariant_set_int(var, 0); // 0表示falsereturn;}// 尝试识别为整数long int_val = strtol(value_str, &endptr, 10);if (*endptr == '\0') {cvariant_set_int(var, (int)int_val);return;}// 尝试识别为浮点数double float_val = strtod(value_str, &endptr);if (*endptr == '\0') {cvariant_set_double(var, float_val);return;}// 尝试识别为带引号的字符串（去除引号）if (value_str[0] == '"' && value_str[strlen(value_str)-1] == '"') {char* str_val = strndup(value_str + 1, strlen(value_str) - 2);cvariant_set_str(var, str_val);free(str_val);return;}// 否则视为普通字符串cvariant_set_str(var, value_str);
}// 添加配置项到链表
static void add_config_node(ConfigParser* parser, const char* key, const char* value) {if (!parser->current_section || !key || !value) return;ConfigNode* node = (ConfigNode*)malloc(sizeof(ConfigNode));node->section = strdup(parser->current_section);node->key = strdup(key);node->value = cvariant_create();set_value_by_type(node->value, value); // 自动识别类型node->next = parser->head;parser->head = node;
}// 解析INI文件
static int parse_ini_file(ConfigParser* parser, const char* filename) {FILE* f = fopen(filename, "r");if (!f) {fprintf(stderr, "无法打开文件: %s\n", filename);return -1;}char line[1024];int line_num = 0;while (fgets(line, sizeof(line), f)) {line_num++;char* content = trim(line);// 跳过空行和注释if (*content == '\0' || *content == ';' || *content == '#') continue;// 解析节名（如[server]）if (*content == '[' && content[strlen(content)-1] == ']') {free(parser->current_section);parser->current_section = strndup(content + 1, strlen(content) - 2);continue;}// 解析键值对（如port=8080）char* eq_pos = strchr(content, '=');if (eq_pos) {*eq_pos = '\0';char* key = trim(content);char* value = trim(eq_pos + 1);add_config_node(parser, key, value);} else {fprintf(stderr, "警告: 无效行 %d: %s\n", line_num, content);}}fclose(f);return 0;
}// 查询配置项
static int query_config(ConfigParser* parser, const char* query) {// 拆分查询为节名和键名（格式：section.key）char* dot_pos = strchr(query, '.');if (!dot_pos) {fprintf(stderr, "查询格式错误，应为: 节名.键名\n");return -1;}char* section = strndup(query, dot_pos - query);char* key = strdup(dot_pos + 1);// 遍历链表查找配置项ConfigNode* node = parser->head;while (node) {if (strcmp(node->section, section) == 0 && strcmp(node->key, key) == 0) {// 根据类型输出值switch (cvariant_get_type(node->value)) {case TYPE_INT:// 布尔值特殊处理if (strcmp(key, "enable") == 0 || strcmp(key, "active") == 0) {printf("%s\n", cvariant_get_int(node->value) ? "true" : "false");} else {printf("%d\n", cvariant_get_int(node->value));}break;case TYPE_DOUBLE:printf("%g\n", cvariant_get_double(node->value));break;case TYPE_STR:printf("%s\n", cvariant_get_str(node->value));break;default:printf("未知类型\n");}free(section);free(key);return 0;}node = node->next;}fprintf(stderr, "未找到配置项: %s\n", query);free(section);free(key);return -1;
}// 列出所有配置项
static void list_all_configs(ConfigParser* parser) {ConfigNode* node = parser->head;while (node) {printf("[%s] %s = ", node->section, node->key);// 根据类型输出值switch (cvariant_get_type(node->value)) {case TYPE_INT:printf("%d (int)\n", cvariant_get_int(node->value));break;case TYPE_DOUBLE:printf("%g (float)\n", cvariant_get_double(node->value));break;case TYPE_STR:printf("%s (string)\n", cvariant_get_str(node->value));break;}node = node->next;}
}// 显示帮助
static void print_help(const char* progname) {printf("用法: %s [选项] <INI文件> [查询]\n", progname);printf("解析INI配置文件并查询值（兼容Linux风格）\n");printf("选项:\n");printf("  -l        列出文件中所有配置项及类型\n");printf("  -h        显示帮助信息\n");printf("查询格式: 节名.键名（如 'server.port'）\n");printf("示例:\n");printf("  %s config.ini server.port      # 查询[server]节的port值\n", progname);printf("  %s -l app.ini                 # 列出app.ini所有配置项\n", progname);printf("  %s settings.ini log.enable    # 查询[log]节的enable值（布尔型）\n", progname);
}int main(int argc, char* argv[]) {if (argc < 2) {print_help(argv[0]);return 1;}int list_mode = 0;const char* filename = NULL;const char* query = NULL;// 解析命令行参数if (strcmp(argv[1], "-h") == 0) {print_help(argv[0]);return 0;} else if (strcmp(argv[1], "-l") == 0) {if (argc < 3) {print_help(argv[0]);return 1;}list_mode = 1;filename = argv[2];} else {filename = argv[1];query = (argc >= 3) ? argv[2] : NULL;if (!query) {print_help(argv[0]);return 1;}}// 解析配置文件ConfigParser* parser = parser_init();if (parse_ini_file(parser, filename) != 0) {parser_free(parser);return 1;}// 执行操作if (list_mode) {list_all_configs(parser);} else {query_config(parser, query);}// 清理资源parser_free(parser);return 0;
}

build confget.c

gcc -o confget.exe confget.c -L . -lcvariant

config.ini

; 示例配置文件
[server]
port = 8080
host = "localhost"
timeout = 30.5
enable = true[log]
path = "C:\logs"
level = info
max_size = 1024

sample output

# 查询[server]节的port（整数）
confget.exe config.ini server.port
# 输出：8080# 查询[server]节的timeout（浮点数）
confget.exe config.ini server.timeout
# 输出：30.5# 查询[server]节的enable（布尔值）
confget.exe config.ini server.enable
# 输出：true# 查询[log]节的path（字符串）
confget.exe config.ini log.path
# 输出：localhost# 列出所有配置项及类型
confget.exe -l config.ini
# 输出：
# [log] max_size = 1024 (int)
# [log] level = info (string)
# [log] path = C:\logs (string)
# [server] enable = 1 (int)
# [server] timeout = 30.5 (float)
# [server] host = localhost (string)
# [server] port = 8080 (int)

probe1.c

#include "cvariant.h"
#include <stdio.h>
#include <string.h>// 自定义类型定义（见上文）
typedef struct { int x; int y; char name[32]; } Point;
static void point_copy(const void* src, void* dest);
static void point_destroy(void* data);int main() {// 1. 注册自定义类型（获取类型ID）TypeId point_type = cvariant_register_custom_type(sizeof(Point),point_copy,point_destroy);printf("注册自定义类型 Point，ID: %d\n", point_type);// 2. 创建变体对象struct CVariant* var = cvariant_create();if (!var) {printf("创建变体失败\n");return 1;}// 3. 测试内置类型cvariant_set_int(var, 123);printf("类型: %d (预期0), 值: %d\n", cvariant_get_type(var), cvariant_get_int(var));cvariant_set_double(var, 3.1415926535);printf("类型: %d (预期2), 值: %lf\n", cvariant_get_type(var), cvariant_get_double(var));cvariant_set_str(var, "测试字符串");printf("类型: %d (预期3), 值: %s\n", cvariant_get_type(var), cvariant_get_str(var));// 4. 测试自定义类型（Point）Point p = {10, 20, "原点"};cvariant_set_custom(var, point_type, &p);if (cvariant_get_type(var) == point_type) {Point p_out;cvariant_get_custom(var, &p_out);printf("类型: %d (预期自定义ID), 值: (%d, %d, %s)\n",cvariant_get_type(var), p_out.x, p_out.y, p_out.name);}// 5. 清理cvariant_destroy(var);return 0;
}// 实现自定义类型的复制和销毁函数
static void point_copy(const void* src, void* dest) {const Point* s = (const Point*)src;Point* d = (Point*)dest;d->x = s->x;d->y = s->y;strncpy(d->name, s->name, sizeof(d->name)-1);
}static void point_destroy(void* data) {// 示例：无动态内存需要释放
}

probe2.c

#include "cvariant.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>// 1. 定义枚举类型（颜色）
typedef enum {RED,GREEN,BLUE,BLACK,WHITE
} Color;// 2. 定义联合体类型（通用数值）
typedef union {int i;float f;double d;
} Number;// 3. 定义包含枚举和联合体的复杂结构体
typedef struct {Color color;       // 枚举成员Number value;      // 联合体成员char name[64];     // 字符串成员
} ComplexData;// ------------------------------
// 枚举类型（Color）的操作函数
// ------------------------------
static void color_copy(const void* src, void* dest) {// 枚举本质是整数，直接复制内存*(Color*)dest = *(const Color*)src;
}static void color_destroy(void* data) {// 枚举无动态内存，无需额外操作
}// ------------------------------
// 联合体类型（Number）的操作函数
// ------------------------------
static void number_copy(const void* src, void* dest) {// 联合体整体复制memcpy(dest, src, sizeof(Number));
}static void number_destroy(void* data) {// 联合体无动态内存，无需额外操作
}// ------------------------------
// 复杂结构体（ComplexData）的操作函数
// ------------------------------
static void complexdata_copy(const void* src, void* dest) {const ComplexData* s = (const ComplexData*)src;ComplexData* d = (ComplexData*)dest;// 分别复制成员（枚举+联合体+字符串）d->color = s->color;d->value = s->value;  // 联合体直接复制strncpy(d->name, s->name, sizeof(d->name)-1);
}static void complexdata_destroy(void* data) {// 若结构体包含动态内存（如malloc的指针），需在此释放// 本示例无动态内存，仅作演示
}int main() {// 1. 注册自定义类型（获取类型ID）TypeId color_type = cvariant_register_custom_type(sizeof(Color), color_copy, color_destroy);TypeId number_type = cvariant_register_custom_type(sizeof(Number), number_copy, number_destroy);TypeId complex_type = cvariant_register_custom_type(sizeof(ComplexData), complexdata_copy, complexdata_destroy);printf("注册类型ID：\n");printf("  Color: %d\n", color_type);printf("  Number: %d\n", number_type);printf("  ComplexData: %d\n\n", complex_type);// 2. 创建变体对象struct CVariant* var = cvariant_create();if (!var) {fprintf(stderr, "创建变体失败\n");return 1;}// 3. 测试枚举类型（Color）Color my_color = BLUE;cvariant_set_custom(var, color_type, &my_color);if (cvariant_get_type(var) == color_type) {Color get_color;cvariant_get_custom(var, &get_color);printf("枚举类型测试：\n");printf("  存储的颜色: %d (BLUE对应值为2)\n", get_color);}// 4. 测试联合体类型（Number）Number my_num;my_num.f = 3.14159f;  // 存储float值cvariant_set_custom(var, number_type, &my_num);if (cvariant_get_type(var) == number_type) {Number get_num;cvariant_get_custom(var, &get_num);printf("\n联合体类型测试：\n");printf("  存储的float值: %f\n", get_num.f);}// 5. 测试复杂结构体（包含枚举和联合体）ComplexData my_complex = {.color = GREEN,.value = {.d = 99.99},  // 联合体存储double.name = "示例数据"};cvariant_set_custom(var, complex_type, &my_complex);if (cvariant_get_type(var) == complex_type) {ComplexData get_complex;cvariant_get_custom(var, &get_complex);printf("\n复杂结构体测试：\n");printf("  颜色枚举值: %d (GREEN对应值为1)\n", get_complex.color);printf("  联合体double值: %lf\n", get_complex.value.d);printf("  名称: %s\n", get_complex.name);}// 6. 清理资源cvariant_destroy(var);return 0;
}

probe3.c

#include "cvariant.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>// 带动态内存的结构体（需要手动释放）
typedef struct {int id;char* name;  // 动态分配的字符串（需malloc/free）float score;
} DynamicData;// 复制函数：深度复制动态内存
static void dynamicdata_copy(const void* src, void* dest) {const DynamicData* s = (const DynamicData*)src;DynamicData* d = (DynamicData*)dest;// 复制基础类型d->id = s->id;d->score = s->score;// 复制动态字符串（关键：手动分配新内存）if (s->name) {d->name = (char*)malloc(strlen(s->name) + 1);  // 分配内存strcpy(d->name, s->name);  // 复制内容} else {d->name = NULL;}
}// 销毁函数：释放动态内存（关键：防止内存泄漏）
static void dynamicdata_destroy(void* data) {DynamicData* d = (DynamicData*)data;if (d->name) {free(d->name);  // 释放动态字符串d->name = NULL;  // 避免野指针}
}int main() {// 1. 注册自定义类型（带动态内存）TypeId dynamic_type = cvariant_register_custom_type(sizeof(DynamicData),dynamicdata_copy,    // 深度复制动态内存dynamicdata_destroy  // 释放动态内存);printf("注册动态类型 ID: %d\n", dynamic_type);// 2. 创建原始数据（带动态内存）DynamicData original;original.id = 1001;original.name = (char*)malloc(strlen("Alice") + 1);  // 手动分配strcpy(original.name, "Alice");original.score = 95.5f;printf("原始数据: id=%d, name=%s, score=%.1f\n", original.id, original.name, original.score);// 3. 用变体类型存储动态数据struct CVariant* var = cvariant_create();cvariant_set_custom(var, dynamic_type, &original);// 4. 从变体中读取数据（验证复制是否正确）if (cvariant_get_type(var) == dynamic_type) {DynamicData copy;cvariant_get_custom(var, &copy);printf("从变体读取: id=%d, name=%s, score=%.1f\n",copy.id, copy.name, copy.score);}// 5. 清理资源// 注意：原始数据的动态内存需要手动释放（变体内部的由destroy处理）free(original.name);  // 释放原始数据的namecvariant_destroy(var);  // 变体销毁时会自动调用dynamicdata_destroyreturn 0;
}